<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <meta name="generator" content="rustdoc"> <meta name="description" content="Source to the Rust file `libstd/io/buffered.rs`."> <meta name="keywords" content="rust, rustlang, rust-lang"> <title>buffered.rs.html -- source</title> <link rel="stylesheet" type="text/css" href="../../../normalize.css"> <link rel="stylesheet" type="text/css" href="../../../rustdoc.css" id="mainThemeStyle"> <link rel="stylesheet" type="text/css" href="../../../dark.css"> <link rel="stylesheet" type="text/css" href="../../../main.css" id="themeStyle"> <script src="../../../storage.js"></script> <link rel="shortcut icon" href="https://doc.rust-lang.org/favicon.ico"> </head> <body class="rustdoc source"> <!--[if lte IE 8]> <div class="warning"> This old browser is unsupported and will most likely display funky things. </div> <![endif]--> <nav class="sidebar"> <div class="sidebar-menu">☰</div> <a href='../../../std/index.html'><img src='https://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png' alt='logo' width='100'></a> </nav> <div class="theme-picker"> <button id="theme-picker" aria-label="Pick another theme!"> <img src="../../../brush.svg" width="18" alt="Pick another theme!"> </button> <div id="theme-choices"></div> </div> <script src="../../../theme.js"></script> <nav class="sub"> <form class="search-form js-only"> <div class="search-container"> <input class="search-input" name="search" autocomplete="off" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"> </div> </form> </nav> <section id='main' class="content"><pre class="line-numbers"><span id="1"> 1</span> <span id="2"> 2</span> <span id="3"> 3</span> <span id="4"> 4</span> <span id="5"> 5</span> <span id="6"> 6</span> <span id="7"> 7</span> <span id="8"> 8</span> <span id="9"> 9</span> <span id="10"> 10</span> <span id="11"> 11</span> <span id="12"> 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id="796"> 796</span> <span id="797"> 797</span> <span id="798"> 798</span> <span id="799"> 799</span> <span id="800"> 800</span> <span id="801"> 801</span> <span id="802"> 802</span> <span id="803"> 803</span> <span id="804"> 804</span> <span id="805"> 805</span> <span id="806"> 806</span> <span id="807"> 807</span> <span id="808"> 808</span> <span id="809"> 809</span> <span id="810"> 810</span> <span id="811"> 811</span> <span id="812"> 812</span> <span id="813"> 813</span> <span id="814"> 814</span> <span id="815"> 815</span> <span id="816"> 816</span> <span id="817"> 817</span> <span id="818"> 818</span> <span id="819"> 819</span> <span id="820"> 820</span> <span id="821"> 821</span> <span id="822"> 822</span> <span id="823"> 823</span> <span id="824"> 824</span> <span id="825"> 825</span> <span id="826"> 826</span> <span id="827"> 827</span> <span id="828"> 828</span> <span id="829"> 829</span> <span id="830"> 830</span> <span id="831"> 831</span> <span id="832"> 832</span> <span id="833"> 833</span> <span id="834"> 834</span> <span id="835"> 835</span> <span id="836"> 836</span> <span id="837"> 837</span> <span id="838"> 838</span> <span id="839"> 839</span> <span id="840"> 840</span> <span id="841"> 841</span> <span id="842"> 842</span> <span id="843"> 843</span> <span id="844"> 844</span> <span id="845"> 845</span> <span id="846"> 846</span> <span id="847"> 847</span> <span id="848"> 848</span> <span id="849"> 849</span> <span id="850"> 850</span> <span id="851"> 851</span> <span id="852"> 852</span> <span id="853"> 853</span> <span id="854"> 854</span> <span id="855"> 855</span> <span id="856"> 856</span> <span id="857"> 857</span> <span id="858"> 858</span> <span id="859"> 859</span> <span id="860"> 860</span> <span id="861"> 861</span> <span id="862"> 862</span> <span id="863"> 863</span> <span id="864"> 864</span> <span id="865"> 865</span> <span id="866"> 866</span> <span id="867"> 867</span> <span id="868"> 868</span> <span id="869"> 869</span> <span id="870"> 870</span> <span id="871"> 871</span> <span id="872"> 872</span> <span id="873"> 873</span> <span id="874"> 874</span> <span id="875"> 875</span> <span id="876"> 876</span> <span id="877"> 877</span> <span id="878"> 878</span> <span id="879"> 879</span> <span id="880"> 880</span> <span id="881"> 881</span> <span id="882"> 882</span> <span id="883"> 883</span> <span id="884"> 884</span> <span id="885"> 885</span> <span id="886"> 886</span> <span id="887"> 887</span> <span id="888"> 888</span> <span id="889"> 889</span> <span id="890"> 890</span> <span id="891"> 891</span> <span id="892"> 892</span> <span id="893"> 893</span> <span id="894"> 894</span> <span id="895"> 895</span> <span id="896"> 896</span> <span id="897"> 897</span> <span id="898"> 898</span> <span id="899"> 899</span> <span id="900"> 900</span> <span id="901"> 901</span> <span id="902"> 902</span> <span id="903"> 903</span> <span id="904"> 904</span> <span id="905"> 905</span> <span id="906"> 906</span> <span id="907"> 907</span> <span id="908"> 908</span> <span id="909"> 909</span> <span id="910"> 910</span> <span id="911"> 911</span> <span id="912"> 912</span> <span id="913"> 913</span> <span id="914"> 914</span> <span id="915"> 915</span> <span id="916"> 916</span> <span id="917"> 917</span> <span id="918"> 918</span> <span id="919"> 919</span> <span id="920"> 920</span> <span id="921"> 921</span> <span id="922"> 922</span> <span id="923"> 923</span> <span id="924"> 924</span> <span id="925"> 925</span> <span id="926"> 926</span> <span id="927"> 927</span> <span id="928"> 928</span> <span id="929"> 929</span> <span id="930"> 930</span> <span id="931"> 931</span> <span id="932"> 932</span> <span id="933"> 933</span> <span id="934"> 934</span> <span id="935"> 935</span> <span id="936"> 936</span> <span id="937"> 937</span> <span id="938"> 938</span> <span id="939"> 939</span> <span id="940"> 940</span> <span id="941"> 941</span> <span id="942"> 942</span> <span id="943"> 943</span> <span id="944"> 944</span> <span id="945"> 945</span> <span id="946"> 946</span> <span id="947"> 947</span> <span id="948"> 948</span> <span id="949"> 949</span> <span id="950"> 950</span> <span id="951"> 951</span> <span id="952"> 952</span> <span id="953"> 953</span> <span id="954"> 954</span> <span id="955"> 955</span> <span id="956"> 956</span> <span id="957"> 957</span> <span id="958"> 958</span> <span id="959"> 959</span> <span id="960"> 960</span> <span id="961"> 961</span> <span id="962"> 962</span> <span id="963"> 963</span> <span id="964"> 964</span> <span id="965"> 965</span> <span id="966"> 966</span> <span id="967"> 967</span> <span id="968"> 968</span> <span id="969"> 969</span> <span id="970"> 970</span> <span id="971"> 971</span> <span id="972"> 972</span> <span id="973"> 973</span> <span id="974"> 974</span> <span id="975"> 975</span> <span id="976"> 976</span> <span id="977"> 977</span> <span id="978"> 978</span> <span id="979"> 979</span> <span id="980"> 980</span> <span id="981"> 981</span> <span id="982"> 982</span> <span id="983"> 983</span> <span id="984"> 984</span> <span id="985"> 985</span> <span id="986"> 986</span> <span id="987"> 987</span> <span id="988"> 988</span> <span id="989"> 989</span> <span id="990"> 990</span> <span id="991"> 991</span> <span id="992"> 992</span> <span id="993"> 993</span> <span id="994"> 994</span> <span id="995"> 995</span> <span id="996"> 996</span> <span id="997"> 997</span> <span id="998"> 998</span> <span id="999"> 999</span> <span id="1000">1000</span> <span id="1001">1001</span> <span id="1002">1002</span> <span id="1003">1003</span> <span id="1004">1004</span> <span id="1005">1005</span> <span id="1006">1006</span> <span id="1007">1007</span> <span id="1008">1008</span> <span id="1009">1009</span> <span id="1010">1010</span> <span id="1011">1011</span> <span id="1012">1012</span> <span id="1013">1013</span> <span id="1014">1014</span> <span id="1015">1015</span> <span id="1016">1016</span> <span id="1017">1017</span> <span id="1018">1018</span> <span id="1019">1019</span> <span id="1020">1020</span> <span id="1021">1021</span> <span id="1022">1022</span> <span id="1023">1023</span> <span id="1024">1024</span> <span id="1025">1025</span> <span id="1026">1026</span> <span id="1027">1027</span> <span id="1028">1028</span> <span id="1029">1029</span> <span id="1030">1030</span> <span id="1031">1031</span> <span id="1032">1032</span> <span id="1033">1033</span> <span id="1034">1034</span> <span id="1035">1035</span> <span id="1036">1036</span> <span id="1037">1037</span> <span id="1038">1038</span> <span id="1039">1039</span> <span id="1040">1040</span> <span id="1041">1041</span> <span id="1042">1042</span> <span id="1043">1043</span> <span id="1044">1044</span> <span id="1045">1045</span> <span id="1046">1046</span> <span id="1047">1047</span> <span id="1048">1048</span> <span id="1049">1049</span> <span id="1050">1050</span> <span id="1051">1051</span> <span id="1052">1052</span> <span id="1053">1053</span> <span id="1054">1054</span> <span id="1055">1055</span> <span id="1056">1056</span> <span id="1057">1057</span> <span id="1058">1058</span> <span id="1059">1059</span> <span id="1060">1060</span> <span id="1061">1061</span> <span id="1062">1062</span> <span id="1063">1063</span> <span id="1064">1064</span> <span id="1065">1065</span> <span id="1066">1066</span> <span id="1067">1067</span> <span id="1068">1068</span> <span id="1069">1069</span> <span id="1070">1070</span> <span id="1071">1071</span> <span id="1072">1072</span> <span id="1073">1073</span> <span id="1074">1074</span> <span id="1075">1075</span> <span id="1076">1076</span> <span id="1077">1077</span> <span id="1078">1078</span> <span id="1079">1079</span> <span id="1080">1080</span> <span id="1081">1081</span> <span id="1082">1082</span> <span id="1083">1083</span> <span id="1084">1084</span> <span id="1085">1085</span> <span id="1086">1086</span> <span id="1087">1087</span> <span id="1088">1088</span> <span id="1089">1089</span> <span id="1090">1090</span> <span id="1091">1091</span> <span id="1092">1092</span> <span id="1093">1093</span> <span id="1094">1094</span> <span id="1095">1095</span> <span id="1096">1096</span> <span id="1097">1097</span> <span id="1098">1098</span> <span id="1099">1099</span> <span id="1100">1100</span> <span id="1101">1101</span> <span id="1102">1102</span> <span id="1103">1103</span> <span id="1104">1104</span> <span id="1105">1105</span> <span id="1106">1106</span> <span id="1107">1107</span> <span id="1108">1108</span> <span id="1109">1109</span> <span id="1110">1110</span> <span id="1111">1111</span> <span id="1112">1112</span> <span id="1113">1113</span> <span id="1114">1114</span> <span id="1115">1115</span> <span id="1116">1116</span> <span id="1117">1117</span> <span id="1118">1118</span> <span id="1119">1119</span> <span id="1120">1120</span> <span id="1121">1121</span> <span id="1122">1122</span> <span id="1123">1123</span> <span id="1124">1124</span> <span id="1125">1125</span> <span id="1126">1126</span> <span id="1127">1127</span> <span id="1128">1128</span> <span id="1129">1129</span> <span id="1130">1130</span> <span id="1131">1131</span> <span id="1132">1132</span> <span id="1133">1133</span> <span id="1134">1134</span> <span id="1135">1135</span> <span id="1136">1136</span> <span id="1137">1137</span> <span id="1138">1138</span> <span id="1139">1139</span> <span id="1140">1140</span> <span id="1141">1141</span> <span id="1142">1142</span> <span id="1143">1143</span> <span id="1144">1144</span> <span id="1145">1145</span> <span id="1146">1146</span> <span id="1147">1147</span> <span id="1148">1148</span> <span id="1149">1149</span> <span id="1150">1150</span> <span id="1151">1151</span> <span id="1152">1152</span> <span id="1153">1153</span> <span id="1154">1154</span> <span id="1155">1155</span> <span id="1156">1156</span> <span id="1157">1157</span> <span id="1158">1158</span> <span id="1159">1159</span> <span id="1160">1160</span> <span id="1161">1161</span> <span id="1162">1162</span> <span id="1163">1163</span> <span id="1164">1164</span> <span id="1165">1165</span> <span id="1166">1166</span> <span id="1167">1167</span> <span id="1168">1168</span> <span id="1169">1169</span> <span id="1170">1170</span> <span id="1171">1171</span> <span id="1172">1172</span> <span id="1173">1173</span> <span id="1174">1174</span> <span id="1175">1175</span> <span id="1176">1176</span> <span id="1177">1177</span> <span id="1178">1178</span> <span id="1179">1179</span> <span id="1180">1180</span> <span id="1181">1181</span> <span id="1182">1182</span> <span id="1183">1183</span> <span id="1184">1184</span> <span id="1185">1185</span> <span id="1186">1186</span> <span id="1187">1187</span> <span id="1188">1188</span> <span id="1189">1189</span> <span id="1190">1190</span> <span id="1191">1191</span> <span id="1192">1192</span> <span id="1193">1193</span> <span id="1194">1194</span> <span id="1195">1195</span> <span id="1196">1196</span> <span id="1197">1197</span> <span id="1198">1198</span> <span id="1199">1199</span> <span id="1200">1200</span> <span id="1201">1201</span> <span id="1202">1202</span> <span id="1203">1203</span> <span id="1204">1204</span> <span id="1205">1205</span> <span id="1206">1206</span> <span id="1207">1207</span> <span id="1208">1208</span> <span id="1209">1209</span> <span id="1210">1210</span> <span id="1211">1211</span> <span id="1212">1212</span> <span id="1213">1213</span> <span id="1214">1214</span> <span id="1215">1215</span> <span id="1216">1216</span> <span id="1217">1217</span> <span id="1218">1218</span> <span id="1219">1219</span> <span id="1220">1220</span> <span id="1221">1221</span> <span id="1222">1222</span> <span id="1223">1223</span> <span id="1224">1224</span> <span id="1225">1225</span> <span id="1226">1226</span> <span id="1227">1227</span> <span id="1228">1228</span> <span id="1229">1229</span> <span id="1230">1230</span> <span id="1231">1231</span> <span id="1232">1232</span> <span id="1233">1233</span> <span id="1234">1234</span> <span id="1235">1235</span> <span id="1236">1236</span> <span id="1237">1237</span> <span id="1238">1238</span> <span id="1239">1239</span> <span id="1240">1240</span> <span id="1241">1241</span> <span id="1242">1242</span> <span id="1243">1243</span> <span id="1244">1244</span> <span id="1245">1245</span> <span id="1246">1246</span> <span id="1247">1247</span> <span id="1248">1248</span> <span id="1249">1249</span> <span id="1250">1250</span> <span id="1251">1251</span> <span id="1252">1252</span> <span id="1253">1253</span> <span id="1254">1254</span> <span id="1255">1255</span> <span id="1256">1256</span> <span id="1257">1257</span> <span id="1258">1258</span> <span id="1259">1259</span> <span id="1260">1260</span> <span id="1261">1261</span> <span id="1262">1262</span> <span id="1263">1263</span> <span id="1264">1264</span> <span id="1265">1265</span> <span id="1266">1266</span> <span id="1267">1267</span> <span id="1268">1268</span> <span id="1269">1269</span> <span id="1270">1270</span> <span id="1271">1271</span> <span id="1272">1272</span> <span id="1273">1273</span> <span id="1274">1274</span> <span id="1275">1275</span> <span id="1276">1276</span> <span id="1277">1277</span> <span id="1278">1278</span> <span id="1279">1279</span> <span id="1280">1280</span> <span id="1281">1281</span> <span id="1282">1282</span> <span id="1283">1283</span> <span id="1284">1284</span> <span id="1285">1285</span> <span id="1286">1286</span> <span id="1287">1287</span> <span id="1288">1288</span> <span id="1289">1289</span> <span id="1290">1290</span> <span id="1291">1291</span> <span id="1292">1292</span> <span id="1293">1293</span> <span id="1294">1294</span> <span id="1295">1295</span> <span id="1296">1296</span> <span id="1297">1297</span> <span id="1298">1298</span> <span id="1299">1299</span> <span id="1300">1300</span> <span id="1301">1301</span> <span id="1302">1302</span> <span id="1303">1303</span> <span id="1304">1304</span> <span id="1305">1305</span> <span id="1306">1306</span> <span id="1307">1307</span> <span id="1308">1308</span> <span id="1309">1309</span> <span id="1310">1310</span> <span id="1311">1311</span> <span id="1312">1312</span> <span id="1313">1313</span> <span id="1314">1314</span> <span id="1315">1315</span> <span id="1316">1316</span> <span id="1317">1317</span> <span id="1318">1318</span> <span id="1319">1319</span> <span id="1320">1320</span> <span id="1321">1321</span> <span id="1322">1322</span> <span id="1323">1323</span> <span id="1324">1324</span> <span id="1325">1325</span> <span id="1326">1326</span> </pre><pre class="rust "> <span class="comment">// Copyright 2013 The Rust Project Developers. See the COPYRIGHT</span> <span class="comment">// file at the top-level directory of this distribution and at</span> <span class="comment">// http://rust-lang.org/COPYRIGHT.</span> <span class="comment">//</span> <span class="comment">// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or</span> <span class="comment">// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license</span> <span class="comment">// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your</span> <span class="comment">// option. This file may not be copied, modified, or distributed</span> <span class="comment">// except according to those terms.</span> <span class="doccomment">//! Buffering wrappers for I/O traits</span> <span class="kw">use</span> <span class="ident">io</span>::<span class="ident">prelude</span>::<span class="kw-2">*</span>; <span class="kw">use</span> <span class="ident">cmp</span>; <span class="kw">use</span> <span class="ident">error</span>; <span class="kw">use</span> <span class="ident">fmt</span>; <span class="kw">use</span> <span class="ident">io</span>::{<span class="self">self</span>, <span class="ident">Initializer</span>, <span class="ident">DEFAULT_BUF_SIZE</span>, <span class="ident">Error</span>, <span class="ident">ErrorKind</span>, <span class="ident">SeekFrom</span>}; <span class="kw">use</span> <span class="ident">memchr</span>; <span class="doccomment">/// The `BufReader` struct adds buffering to any reader.</span> <span class="doccomment">///</span> <span class="doccomment">/// It can be excessively inefficient to work directly with a [`Read`] instance.</span> <span class="doccomment">/// For example, every call to [`read`][`TcpStream::read`] on [`TcpStream`]</span> <span class="doccomment">/// results in a system call. A `BufReader` performs large, infrequent reads on</span> <span class="doccomment">/// the underlying [`Read`] and maintains an in-memory buffer of the results.</span> <span class="doccomment">///</span> <span class="doccomment">/// [`Read`]: ../../std/io/trait.Read.html</span> <span class="doccomment">/// [`TcpStream::read`]: ../../std/net/struct.TcpStream.html#method.read</span> <span class="doccomment">/// [`TcpStream`]: ../../std/net/struct.TcpStream.html</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// use std::io::prelude::*;</span> <span class="doccomment">/// use std::io::BufReader;</span> <span class="doccomment">/// use std::fs::File;</span> <span class="doccomment">///</span> <span class="doccomment">/// # fn foo() -> std::io::Result<()> {</span> <span class="doccomment">/// let f = File::open("log.txt")?;</span> <span class="doccomment">/// let mut reader = BufReader::new(f);</span> <span class="doccomment">///</span> <span class="doccomment">/// let mut line = String::new();</span> <span class="doccomment">/// let len = reader.read_line(&mut line)?;</span> <span class="doccomment">/// println!("First line is {} bytes long", len);</span> <span class="doccomment">/// # Ok(())</span> <span class="doccomment">/// # }</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">BufReader</span><span class="op"><</span><span class="ident">R</span><span class="op">></span> { <span class="ident">inner</span>: <span class="ident">R</span>, <span class="ident">buf</span>: <span class="ident">Box</span><span class="op"><</span>[<span class="ident">u8</span>]<span class="op">></span>, <span class="ident">pos</span>: <span class="ident">usize</span>, <span class="ident">cap</span>: <span class="ident">usize</span>, } <span class="kw">impl</span><span class="op"><</span><span class="ident">R</span>: <span class="ident">Read</span><span class="op">></span> <span class="ident">BufReader</span><span class="op"><</span><span class="ident">R</span><span class="op">></span> { <span class="doccomment">/// Creates a new `BufReader` with a default buffer capacity.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// use std::io::BufReader;</span> <span class="doccomment">/// use std::fs::File;</span> <span class="doccomment">///</span> <span class="doccomment">/// # fn foo() -> std::io::Result<()> {</span> <span class="doccomment">/// let f = File::open("log.txt")?;</span> <span class="doccomment">/// let reader = BufReader::new(f);</span> <span class="doccomment">/// # Ok(())</span> <span class="doccomment">/// # }</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">inner</span>: <span class="ident">R</span>) <span class="op">-></span> <span class="ident">BufReader</span><span class="op"><</span><span class="ident">R</span><span class="op">></span> { <span class="ident">BufReader</span>::<span class="ident">with_capacity</span>(<span class="ident">DEFAULT_BUF_SIZE</span>, <span class="ident">inner</span>) } <span class="doccomment">/// Creates a new `BufReader` with the specified buffer capacity.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// Creating a buffer with ten bytes of capacity:</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// use std::io::BufReader;</span> <span class="doccomment">/// use std::fs::File;</span> <span class="doccomment">///</span> <span class="doccomment">/// # fn foo() -> std::io::Result<()> {</span> <span class="doccomment">/// let f = File::open("log.txt")?;</span> <span class="doccomment">/// let reader = BufReader::with_capacity(10, f);</span> <span class="doccomment">/// # Ok(())</span> <span class="doccomment">/// # }</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">with_capacity</span>(<span class="ident">cap</span>: <span class="ident">usize</span>, <span class="ident">inner</span>: <span class="ident">R</span>) <span class="op">-></span> <span class="ident">BufReader</span><span class="op"><</span><span class="ident">R</span><span class="op">></span> { <span class="kw">unsafe</span> { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buffer</span> <span class="op">=</span> <span class="ident">Vec</span>::<span class="ident">with_capacity</span>(<span class="ident">cap</span>); <span class="ident">buffer</span>.<span class="ident">set_len</span>(<span class="ident">cap</span>); <span class="ident">inner</span>.<span class="ident">initializer</span>().<span class="ident">initialize</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buffer</span>); <span class="ident">BufReader</span> { <span class="ident">inner</span>, <span class="ident">buf</span>: <span class="ident">buffer</span>.<span class="ident">into_boxed_slice</span>(), <span class="ident">pos</span>: <span class="number">0</span>, <span class="ident">cap</span>: <span class="number">0</span>, } } } <span class="doccomment">/// Gets a reference to the underlying reader.</span> <span class="doccomment">///</span> <span class="doccomment">/// It is inadvisable to directly read from the underlying reader.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// use std::io::BufReader;</span> <span class="doccomment">/// use std::fs::File;</span> <span class="doccomment">///</span> <span class="doccomment">/// # fn foo() -> std::io::Result<()> {</span> <span class="doccomment">/// let f1 = File::open("log.txt")?;</span> <span class="doccomment">/// let reader = BufReader::new(f1);</span> <span class="doccomment">///</span> <span class="doccomment">/// let f2 = reader.get_ref();</span> <span class="doccomment">/// # Ok(())</span> <span class="doccomment">/// # }</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">get_ref</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="ident">R</span> { <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">inner</span> } <span class="doccomment">/// Gets a mutable reference to the underlying reader.</span> <span class="doccomment">///</span> <span class="doccomment">/// It is inadvisable to directly read from the underlying reader.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// use std::io::BufReader;</span> <span class="doccomment">/// use std::fs::File;</span> <span class="doccomment">///</span> <span class="doccomment">/// # fn foo() -> std::io::Result<()> {</span> <span class="doccomment">/// let f1 = File::open("log.txt")?;</span> <span class="doccomment">/// let mut reader = BufReader::new(f1);</span> <span class="doccomment">///</span> <span class="doccomment">/// let f2 = reader.get_mut();</span> <span class="doccomment">/// # Ok(())</span> <span class="doccomment">/// # }</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">get_mut</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">R</span> { <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>.<span class="ident">inner</span> } <span class="doccomment">/// Returns `true` if there are no bytes in the internal buffer.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// # #![feature(bufreader_is_empty)]</span> <span class="doccomment">/// use std::io::BufReader;</span> <span class="doccomment">/// use std::io::BufRead;</span> <span class="doccomment">/// use std::fs::File;</span> <span class="doccomment">///</span> <span class="doccomment">/// # fn foo() -> std::io::Result<()> {</span> <span class="doccomment">/// let f1 = File::open("log.txt")?;</span> <span class="doccomment">/// let mut reader = BufReader::new(f1);</span> <span class="doccomment">/// assert!(reader.is_empty());</span> <span class="doccomment">///</span> <span class="doccomment">/// if reader.fill_buf()?.len() > 0 {</span> <span class="doccomment">/// assert!(!reader.is_empty());</span> <span class="doccomment">/// }</span> <span class="doccomment">/// # Ok(())</span> <span class="doccomment">/// # }</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">unstable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"bufreader_is_empty"</span>, <span class="ident">issue</span> <span class="op">=</span> <span class="string">"45323"</span>, <span class="ident">reason</span> <span class="op">=</span> <span class="string">"recently added"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_empty</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">bool</span> { <span class="self">self</span>.<span class="ident">pos</span> <span class="op">==</span> <span class="self">self</span>.<span class="ident">cap</span> } <span class="doccomment">/// Unwraps this `BufReader`, returning the underlying reader.</span> <span class="doccomment">///</span> <span class="doccomment">/// Note that any leftover data in the internal buffer is lost.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// use std::io::BufReader;</span> <span class="doccomment">/// use std::fs::File;</span> <span class="doccomment">///</span> <span class="doccomment">/// # fn foo() -> std::io::Result<()> {</span> <span class="doccomment">/// let f1 = File::open("log.txt")?;</span> <span class="doccomment">/// let reader = BufReader::new(f1);</span> <span class="doccomment">///</span> <span class="doccomment">/// let f2 = reader.into_inner();</span> <span class="doccomment">/// # Ok(())</span> <span class="doccomment">/// # }</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">into_inner</span>(<span class="self">self</span>) <span class="op">-></span> <span class="ident">R</span> { <span class="self">self</span>.<span class="ident">inner</span> } } <span class="kw">impl</span><span class="op"><</span><span class="ident">R</span>: <span class="ident">Seek</span><span class="op">></span> <span class="ident">BufReader</span><span class="op"><</span><span class="ident">R</span><span class="op">></span> { <span class="doccomment">/// Seeks relative to the current position. If the new position lies within the buffer,</span> <span class="doccomment">/// the buffer will not be flushed, allowing for more efficient seeks.</span> <span class="doccomment">/// This method does not return the location of the underlying reader, so the caller</span> <span class="doccomment">/// must track this information themselves if it is required.</span> <span class="attribute">#[<span class="ident">unstable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"bufreader_seek_relative"</span>, <span class="ident">issue</span> <span class="op">=</span> <span class="string">"31100"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">seek_relative</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">offset</span>: <span class="ident">i64</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> { <span class="kw">let</span> <span class="ident">pos</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">pos</span> <span class="kw">as</span> <span class="ident">u64</span>; <span class="kw">if</span> <span class="ident">offset</span> <span class="op"><</span> <span class="number">0</span> { <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">new_pos</span>) <span class="op">=</span> <span class="ident">pos</span>.<span class="ident">checked_sub</span>((<span class="op">-</span><span class="ident">offset</span>) <span class="kw">as</span> <span class="ident">u64</span>) { <span class="self">self</span>.<span class="ident">pos</span> <span class="op">=</span> <span class="ident">new_pos</span> <span class="kw">as</span> <span class="ident">usize</span>; <span class="kw">return</span> <span class="prelude-val">Ok</span>(()) } } <span class="kw">else</span> { <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">new_pos</span>) <span class="op">=</span> <span class="ident">pos</span>.<span class="ident">checked_add</span>(<span class="ident">offset</span> <span class="kw">as</span> <span class="ident">u64</span>) { <span class="kw">if</span> <span class="ident">new_pos</span> <span class="op"><=</span> <span class="self">self</span>.<span class="ident">cap</span> <span class="kw">as</span> <span class="ident">u64</span> { <span class="self">self</span>.<span class="ident">pos</span> <span class="op">=</span> <span class="ident">new_pos</span> <span class="kw">as</span> <span class="ident">usize</span>; <span class="kw">return</span> <span class="prelude-val">Ok</span>(()) } } } <span class="self">self</span>.<span class="ident">seek</span>(<span class="ident">SeekFrom</span>::<span class="ident">Current</span>(<span class="ident">offset</span>)).<span class="ident">map</span>(<span class="op">|</span>_<span class="op">|</span>()) } } <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">R</span>: <span class="ident">Read</span><span class="op">></span> <span class="ident">Read</span> <span class="kw">for</span> <span class="ident">BufReader</span><span class="op"><</span><span class="ident">R</span><span class="op">></span> { <span class="kw">fn</span> <span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">buf</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> [<span class="ident">u8</span>]) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> { <span class="comment">// If we don't have any buffered data and we're doing a massive read</span> <span class="comment">// (larger than our internal buffer), bypass our internal buffer</span> <span class="comment">// entirely.</span> <span class="kw">if</span> <span class="self">self</span>.<span class="ident">pos</span> <span class="op">==</span> <span class="self">self</span>.<span class="ident">cap</span> <span class="op">&&</span> <span class="ident">buf</span>.<span class="ident">len</span>() <span class="op">>=</span> <span class="self">self</span>.<span class="ident">buf</span>.<span class="ident">len</span>() { <span class="kw">return</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">read</span>(<span class="ident">buf</span>); } <span class="kw">let</span> <span class="ident">nread</span> <span class="op">=</span> { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">rem</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">fill_buf</span>()<span class="question-mark">?</span>; <span class="ident">rem</span>.<span class="ident">read</span>(<span class="ident">buf</span>)<span class="question-mark">?</span> }; <span class="self">self</span>.<span class="ident">consume</span>(<span class="ident">nread</span>); <span class="prelude-val">Ok</span>(<span class="ident">nread</span>) } <span class="comment">// we can't skip unconditionally because of the large buffer case in read.</span> <span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">initializer</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">Initializer</span> { <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">initializer</span>() } } <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">R</span>: <span class="ident">Read</span><span class="op">></span> <span class="ident">BufRead</span> <span class="kw">for</span> <span class="ident">BufReader</span><span class="op"><</span><span class="ident">R</span><span class="op">></span> { <span class="kw">fn</span> <span class="ident">fill_buf</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="kw-2">&</span>[<span class="ident">u8</span>]<span class="op">></span> { <span class="comment">// If we've reached the end of our internal buffer then we need to fetch</span> <span class="comment">// some more data from the underlying reader.</span> <span class="comment">// Branch using `>=` instead of the more correct `==`</span> <span class="comment">// to tell the compiler that the pos..cap slice is always valid.</span> <span class="kw">if</span> <span class="self">self</span>.<span class="ident">pos</span> <span class="op">>=</span> <span class="self">self</span>.<span class="ident">cap</span> { <span class="macro">debug_assert</span><span class="macro">!</span>(<span class="self">self</span>.<span class="ident">pos</span> <span class="op">==</span> <span class="self">self</span>.<span class="ident">cap</span>); <span class="self">self</span>.<span class="ident">cap</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>.<span class="ident">buf</span>)<span class="question-mark">?</span>; <span class="self">self</span>.<span class="ident">pos</span> <span class="op">=</span> <span class="number">0</span>; } <span class="prelude-val">Ok</span>(<span class="kw-2">&</span><span class="self">self</span>.<span class="ident">buf</span>[<span class="self">self</span>.<span class="ident">pos</span>..<span class="self">self</span>.<span class="ident">cap</span>]) } <span class="kw">fn</span> <span class="ident">consume</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">amt</span>: <span class="ident">usize</span>) { <span class="self">self</span>.<span class="ident">pos</span> <span class="op">=</span> <span class="ident">cmp</span>::<span class="ident">min</span>(<span class="self">self</span>.<span class="ident">pos</span> <span class="op">+</span> <span class="ident">amt</span>, <span class="self">self</span>.<span class="ident">cap</span>); } } <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">R</span><span class="op">></span> <span class="ident">fmt</span>::<span class="ident">Debug</span> <span class="kw">for</span> <span class="ident">BufReader</span><span class="op"><</span><span class="ident">R</span><span class="op">></span> <span class="kw">where</span> <span class="ident">R</span>: <span class="ident">fmt</span>::<span class="ident">Debug</span> { <span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">fmt</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt</span>::<span class="ident">Formatter</span>) <span class="op">-></span> <span class="ident">fmt</span>::<span class="prelude-ty">Result</span> { <span class="ident">fmt</span>.<span class="ident">debug_struct</span>(<span class="string">"BufReader"</span>) .<span class="ident">field</span>(<span class="string">"reader"</span>, <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">inner</span>) .<span class="ident">field</span>(<span class="string">"buffer"</span>, <span class="kw-2">&</span><span class="macro">format_args</span><span class="macro">!</span>(<span class="string">"{}/{}"</span>, <span class="self">self</span>.<span class="ident">cap</span> <span class="op">-</span> <span class="self">self</span>.<span class="ident">pos</span>, <span class="self">self</span>.<span class="ident">buf</span>.<span class="ident">len</span>())) .<span class="ident">finish</span>() } } <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">R</span>: <span class="ident">Seek</span><span class="op">></span> <span class="ident">Seek</span> <span class="kw">for</span> <span class="ident">BufReader</span><span class="op"><</span><span class="ident">R</span><span class="op">></span> { <span class="doccomment">/// Seek to an offset, in bytes, in the underlying reader.</span> <span class="doccomment">///</span> <span class="doccomment">/// The position used for seeking with `SeekFrom::Current(_)` is the</span> <span class="doccomment">/// position the underlying reader would be at if the `BufReader` had no</span> <span class="doccomment">/// internal buffer.</span> <span class="doccomment">///</span> <span class="doccomment">/// Seeking always discards the internal buffer, even if the seek position</span> <span class="doccomment">/// would otherwise fall within it. This guarantees that calling</span> <span class="doccomment">/// `.into_inner()` immediately after a seek yields the underlying reader</span> <span class="doccomment">/// at the same position.</span> <span class="doccomment">///</span> <span class="doccomment">/// To seek without discarding the internal buffer, use [`seek_relative`].</span> <span class="doccomment">///</span> <span class="doccomment">/// See `std::io::Seek` for more details.</span> <span class="doccomment">///</span> <span class="doccomment">/// Note: In the edge case where you're seeking with `SeekFrom::Current(n)`</span> <span class="doccomment">/// where `n` minus the internal buffer length overflows an `i64`, two</span> <span class="doccomment">/// seeks will be performed instead of one. If the second seek returns</span> <span class="doccomment">/// `Err`, the underlying reader will be left at the same position it would</span> <span class="doccomment">/// have if you seeked to `SeekFrom::Current(0)`.</span> <span class="doccomment">///</span> <span class="doccomment">/// [`seek_relative`]: #method.seek_relative</span> <span class="kw">fn</span> <span class="ident">seek</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">pos</span>: <span class="ident">SeekFrom</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">u64</span><span class="op">></span> { <span class="kw">let</span> <span class="ident">result</span>: <span class="ident">u64</span>; <span class="kw">if</span> <span class="kw">let</span> <span class="ident">SeekFrom</span>::<span class="ident">Current</span>(<span class="ident">n</span>) <span class="op">=</span> <span class="ident">pos</span> { <span class="kw">let</span> <span class="ident">remainder</span> <span class="op">=</span> (<span class="self">self</span>.<span class="ident">cap</span> <span class="op">-</span> <span class="self">self</span>.<span class="ident">pos</span>) <span class="kw">as</span> <span class="ident">i64</span>; <span class="comment">// it should be safe to assume that remainder fits within an i64 as the alternative</span> <span class="comment">// means we managed to allocate 8 exbibytes and that's absurd.</span> <span class="comment">// But it's not out of the realm of possibility for some weird underlying reader to</span> <span class="comment">// support seeking by i64::min_value() so we need to handle underflow when subtracting</span> <span class="comment">// remainder.</span> <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Some</span>(<span class="ident">offset</span>) <span class="op">=</span> <span class="ident">n</span>.<span class="ident">checked_sub</span>(<span class="ident">remainder</span>) { <span class="ident">result</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">seek</span>(<span class="ident">SeekFrom</span>::<span class="ident">Current</span>(<span class="ident">offset</span>))<span class="question-mark">?</span>; } <span class="kw">else</span> { <span class="comment">// seek backwards by our remainder, and then by the offset</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">seek</span>(<span class="ident">SeekFrom</span>::<span class="ident">Current</span>(<span class="op">-</span><span class="ident">remainder</span>))<span class="question-mark">?</span>; <span class="self">self</span>.<span class="ident">pos</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">cap</span>; <span class="comment">// empty the buffer</span> <span class="ident">result</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">seek</span>(<span class="ident">SeekFrom</span>::<span class="ident">Current</span>(<span class="ident">n</span>))<span class="question-mark">?</span>; } } <span class="kw">else</span> { <span class="comment">// Seeking with Start/End doesn't care about our buffer length.</span> <span class="ident">result</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">seek</span>(<span class="ident">pos</span>)<span class="question-mark">?</span>; } <span class="self">self</span>.<span class="ident">pos</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">cap</span>; <span class="comment">// empty the buffer</span> <span class="prelude-val">Ok</span>(<span class="ident">result</span>) } } <span class="doccomment">/// Wraps a writer and buffers its output.</span> <span class="doccomment">///</span> <span class="doccomment">/// It can be excessively inefficient to work directly with something that</span> <span class="doccomment">/// implements [`Write`]. For example, every call to</span> <span class="doccomment">/// [`write`][`Tcpstream::write`] on [`TcpStream`] results in a system call. A</span> <span class="doccomment">/// `BufWriter` keeps an in-memory buffer of data and writes it to an underlying</span> <span class="doccomment">/// writer in large, infrequent batches.</span> <span class="doccomment">///</span> <span class="doccomment">/// When the `BufWriter` is dropped, the contents of its buffer will be written</span> <span class="doccomment">/// out. However, any errors that happen in the process of flushing the buffer</span> <span class="doccomment">/// when the writer is dropped will be ignored. Code that wishes to handle such</span> <span class="doccomment">/// errors must manually call [`flush`] before the writer is dropped.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// Let's write the numbers one through ten to a [`TcpStream`]:</span> <span class="doccomment">///</span> <span class="doccomment">/// ```no_run</span> <span class="doccomment">/// use std::io::prelude::*;</span> <span class="doccomment">/// use std::net::TcpStream;</span> <span class="doccomment">///</span> <span class="doccomment">/// let mut stream = TcpStream::connect("127.0.0.1:34254").unwrap();</span> <span class="doccomment">///</span> <span class="doccomment">/// for i in 0..10 {</span> <span class="doccomment">/// stream.write(&[i+1]).unwrap();</span> <span class="doccomment">/// }</span> <span class="doccomment">/// ```</span> <span class="doccomment">///</span> <span class="doccomment">/// Because we're not buffering, we write each one in turn, incurring the</span> <span class="doccomment">/// overhead of a system call per byte written. We can fix this with a</span> <span class="doccomment">/// `BufWriter`:</span> <span class="doccomment">///</span> <span class="doccomment">/// ```no_run</span> <span class="doccomment">/// use std::io::prelude::*;</span> <span class="doccomment">/// use std::io::BufWriter;</span> <span class="doccomment">/// use std::net::TcpStream;</span> <span class="doccomment">///</span> <span class="doccomment">/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());</span> <span class="doccomment">///</span> <span class="doccomment">/// for i in 0..10 {</span> <span class="doccomment">/// stream.write(&[i+1]).unwrap();</span> <span class="doccomment">/// }</span> <span class="doccomment">/// ```</span> <span class="doccomment">///</span> <span class="doccomment">/// By wrapping the stream with a `BufWriter`, these ten writes are all grouped</span> <span class="doccomment">/// together by the buffer, and will all be written out in one system call when</span> <span class="doccomment">/// the `stream` is dropped.</span> <span class="doccomment">///</span> <span class="doccomment">/// [`Write`]: ../../std/io/trait.Write.html</span> <span class="doccomment">/// [`Tcpstream::write`]: ../../std/net/struct.TcpStream.html#method.write</span> <span class="doccomment">/// [`TcpStream`]: ../../std/net/struct.TcpStream.html</span> <span class="doccomment">/// [`flush`]: #method.flush</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">BufWriter</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> { <span class="ident">inner</span>: <span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">W</span><span class="op">></span>, <span class="ident">buf</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">u8</span><span class="op">></span>, <span class="comment">// #30888: If the inner writer panics in a call to write, we don't want to</span> <span class="comment">// write the buffered data a second time in BufWriter's destructor. This</span> <span class="comment">// flag tells the Drop impl if it should skip the flush.</span> <span class="ident">panicked</span>: <span class="ident">bool</span>, } <span class="doccomment">/// An error returned by `into_inner` which combines an error that</span> <span class="doccomment">/// happened while writing out the buffer, and the buffered writer object</span> <span class="doccomment">/// which may be used to recover from the condition.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```no_run</span> <span class="doccomment">/// use std::io::BufWriter;</span> <span class="doccomment">/// use std::net::TcpStream;</span> <span class="doccomment">///</span> <span class="doccomment">/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());</span> <span class="doccomment">///</span> <span class="doccomment">/// // do stuff with the stream</span> <span class="doccomment">///</span> <span class="doccomment">/// // we want to get our `TcpStream` back, so let's try:</span> <span class="doccomment">///</span> <span class="doccomment">/// let stream = match stream.into_inner() {</span> <span class="doccomment">/// Ok(s) => s,</span> <span class="doccomment">/// Err(e) => {</span> <span class="doccomment">/// // Here, e is an IntoInnerError</span> <span class="doccomment">/// panic!("An error occurred");</span> <span class="doccomment">/// }</span> <span class="doccomment">/// };</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Debug</span>)]</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">IntoInnerError</span><span class="op"><</span><span class="ident">W</span><span class="op">></span>(<span class="ident">W</span>, <span class="ident">Error</span>); <span class="kw">impl</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> <span class="ident">BufWriter</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> { <span class="doccomment">/// Creates a new `BufWriter` with a default buffer capacity.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```no_run</span> <span class="doccomment">/// use std::io::BufWriter;</span> <span class="doccomment">/// use std::net::TcpStream;</span> <span class="doccomment">///</span> <span class="doccomment">/// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">inner</span>: <span class="ident">W</span>) <span class="op">-></span> <span class="ident">BufWriter</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> { <span class="ident">BufWriter</span>::<span class="ident">with_capacity</span>(<span class="ident">DEFAULT_BUF_SIZE</span>, <span class="ident">inner</span>) } <span class="doccomment">/// Creates a new `BufWriter` with the specified buffer capacity.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// Creating a buffer with a buffer of a hundred bytes.</span> <span class="doccomment">///</span> <span class="doccomment">/// ```no_run</span> <span class="doccomment">/// use std::io::BufWriter;</span> <span class="doccomment">/// use std::net::TcpStream;</span> <span class="doccomment">///</span> <span class="doccomment">/// let stream = TcpStream::connect("127.0.0.1:34254").unwrap();</span> <span class="doccomment">/// let mut buffer = BufWriter::with_capacity(100, stream);</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">with_capacity</span>(<span class="ident">cap</span>: <span class="ident">usize</span>, <span class="ident">inner</span>: <span class="ident">W</span>) <span class="op">-></span> <span class="ident">BufWriter</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> { <span class="ident">BufWriter</span> { <span class="ident">inner</span>: <span class="prelude-val">Some</span>(<span class="ident">inner</span>), <span class="ident">buf</span>: <span class="ident">Vec</span>::<span class="ident">with_capacity</span>(<span class="ident">cap</span>), <span class="ident">panicked</span>: <span class="bool-val">false</span>, } } <span class="kw">fn</span> <span class="ident">flush_buf</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">written</span> <span class="op">=</span> <span class="number">0</span>; <span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">buf</span>.<span class="ident">len</span>(); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">ret</span> <span class="op">=</span> <span class="prelude-val">Ok</span>(()); <span class="kw">while</span> <span class="ident">written</span> <span class="op"><</span> <span class="ident">len</span> { <span class="self">self</span>.<span class="ident">panicked</span> <span class="op">=</span> <span class="bool-val">true</span>; <span class="kw">let</span> <span class="ident">r</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">as_mut</span>().<span class="ident">unwrap</span>().<span class="ident">write</span>(<span class="kw-2">&</span><span class="self">self</span>.<span class="ident">buf</span>[<span class="ident">written</span>..]); <span class="self">self</span>.<span class="ident">panicked</span> <span class="op">=</span> <span class="bool-val">false</span>; <span class="kw">match</span> <span class="ident">r</span> { <span class="prelude-val">Ok</span>(<span class="number">0</span>) <span class="op">=></span> { <span class="ident">ret</span> <span class="op">=</span> <span class="prelude-val">Err</span>(<span class="ident">Error</span>::<span class="ident">new</span>(<span class="ident">ErrorKind</span>::<span class="ident">WriteZero</span>, <span class="string">"failed to write the buffered data"</span>)); <span class="kw">break</span>; } <span class="prelude-val">Ok</span>(<span class="ident">n</span>) <span class="op">=></span> <span class="ident">written</span> <span class="op">+=</span> <span class="ident">n</span>, <span class="prelude-val">Err</span>(<span class="kw-2">ref</span> <span class="ident">e</span>) <span class="kw">if</span> <span class="ident">e</span>.<span class="ident">kind</span>() <span class="op">==</span> <span class="ident">io</span>::<span class="ident">ErrorKind</span>::<span class="ident">Interrupted</span> <span class="op">=></span> {} <span class="prelude-val">Err</span>(<span class="ident">e</span>) <span class="op">=></span> { <span class="ident">ret</span> <span class="op">=</span> <span class="prelude-val">Err</span>(<span class="ident">e</span>); <span class="kw">break</span> } } } <span class="kw">if</span> <span class="ident">written</span> <span class="op">></span> <span class="number">0</span> { <span class="self">self</span>.<span class="ident">buf</span>.<span class="ident">drain</span>(..<span class="ident">written</span>); } <span class="ident">ret</span> } <span class="doccomment">/// Gets a reference to the underlying writer.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```no_run</span> <span class="doccomment">/// use std::io::BufWriter;</span> <span class="doccomment">/// use std::net::TcpStream;</span> <span class="doccomment">///</span> <span class="doccomment">/// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());</span> <span class="doccomment">///</span> <span class="doccomment">/// // we can use reference just like buffer</span> <span class="doccomment">/// let reference = buffer.get_ref();</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">get_ref</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="ident">W</span> { <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">as_ref</span>().<span class="ident">unwrap</span>() } <span class="doccomment">/// Gets a mutable reference to the underlying writer.</span> <span class="doccomment">///</span> <span class="doccomment">/// It is inadvisable to directly write to the underlying writer.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```no_run</span> <span class="doccomment">/// use std::io::BufWriter;</span> <span class="doccomment">/// use std::net::TcpStream;</span> <span class="doccomment">///</span> <span class="doccomment">/// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());</span> <span class="doccomment">///</span> <span class="doccomment">/// // we can use reference just like buffer</span> <span class="doccomment">/// let reference = buffer.get_mut();</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">get_mut</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">W</span> { <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">as_mut</span>().<span class="ident">unwrap</span>() } <span class="doccomment">/// Unwraps this `BufWriter`, returning the underlying writer.</span> <span class="doccomment">///</span> <span class="doccomment">/// The buffer is written out before returning the writer.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Errors</span> <span class="doccomment">///</span> <span class="doccomment">/// An `Err` will be returned if an error occurs while flushing the buffer.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```no_run</span> <span class="doccomment">/// use std::io::BufWriter;</span> <span class="doccomment">/// use std::net::TcpStream;</span> <span class="doccomment">///</span> <span class="doccomment">/// let mut buffer = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());</span> <span class="doccomment">///</span> <span class="doccomment">/// // unwrap the TcpStream and flush the buffer</span> <span class="doccomment">/// let stream = buffer.into_inner().unwrap();</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">into_inner</span>(<span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">W</span>, <span class="ident">IntoInnerError</span><span class="op"><</span><span class="ident">BufWriter</span><span class="op"><</span><span class="ident">W</span><span class="op">>></span><span class="op">></span> { <span class="kw">match</span> <span class="self">self</span>.<span class="ident">flush_buf</span>() { <span class="prelude-val">Err</span>(<span class="ident">e</span>) <span class="op">=></span> <span class="prelude-val">Err</span>(<span class="ident">IntoInnerError</span>(<span class="self">self</span>, <span class="ident">e</span>)), <span class="prelude-val">Ok</span>(()) <span class="op">=></span> <span class="prelude-val">Ok</span>(<span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">take</span>().<span class="ident">unwrap</span>()) } } } <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> <span class="ident">Write</span> <span class="kw">for</span> <span class="ident">BufWriter</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> { <span class="kw">fn</span> <span class="ident">write</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">buf</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>]) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> { <span class="kw">if</span> <span class="self">self</span>.<span class="ident">buf</span>.<span class="ident">len</span>() <span class="op">+</span> <span class="ident">buf</span>.<span class="ident">len</span>() <span class="op">></span> <span class="self">self</span>.<span class="ident">buf</span>.<span class="ident">capacity</span>() { <span class="self">self</span>.<span class="ident">flush_buf</span>()<span class="question-mark">?</span>; } <span class="kw">if</span> <span class="ident">buf</span>.<span class="ident">len</span>() <span class="op">>=</span> <span class="self">self</span>.<span class="ident">buf</span>.<span class="ident">capacity</span>() { <span class="self">self</span>.<span class="ident">panicked</span> <span class="op">=</span> <span class="bool-val">true</span>; <span class="kw">let</span> <span class="ident">r</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">as_mut</span>().<span class="ident">unwrap</span>().<span class="ident">write</span>(<span class="ident">buf</span>); <span class="self">self</span>.<span class="ident">panicked</span> <span class="op">=</span> <span class="bool-val">false</span>; <span class="ident">r</span> } <span class="kw">else</span> { <span class="ident">Write</span>::<span class="ident">write</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>.<span class="ident">buf</span>, <span class="ident">buf</span>) } } <span class="kw">fn</span> <span class="ident">flush</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> { <span class="self">self</span>.<span class="ident">flush_buf</span>().<span class="ident">and_then</span>(<span class="op">|</span>()<span class="op">|</span> <span class="self">self</span>.<span class="ident">get_mut</span>().<span class="ident">flush</span>()) } } <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> <span class="ident">fmt</span>::<span class="ident">Debug</span> <span class="kw">for</span> <span class="ident">BufWriter</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> <span class="kw">where</span> <span class="ident">W</span>: <span class="ident">fmt</span>::<span class="ident">Debug</span> { <span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">fmt</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt</span>::<span class="ident">Formatter</span>) <span class="op">-></span> <span class="ident">fmt</span>::<span class="prelude-ty">Result</span> { <span class="ident">fmt</span>.<span class="ident">debug_struct</span>(<span class="string">"BufWriter"</span>) .<span class="ident">field</span>(<span class="string">"writer"</span>, <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">as_ref</span>().<span class="ident">unwrap</span>()) .<span class="ident">field</span>(<span class="string">"buffer"</span>, <span class="kw-2">&</span><span class="macro">format_args</span><span class="macro">!</span>(<span class="string">"{}/{}"</span>, <span class="self">self</span>.<span class="ident">buf</span>.<span class="ident">len</span>(), <span class="self">self</span>.<span class="ident">buf</span>.<span class="ident">capacity</span>())) .<span class="ident">finish</span>() } } <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span> <span class="op">+</span> <span class="ident">Seek</span><span class="op">></span> <span class="ident">Seek</span> <span class="kw">for</span> <span class="ident">BufWriter</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> { <span class="doccomment">/// Seek to the offset, in bytes, in the underlying writer.</span> <span class="doccomment">///</span> <span class="doccomment">/// Seeking always writes out the internal buffer before seeking.</span> <span class="kw">fn</span> <span class="ident">seek</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">pos</span>: <span class="ident">SeekFrom</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">u64</span><span class="op">></span> { <span class="self">self</span>.<span class="ident">flush_buf</span>().<span class="ident">and_then</span>(<span class="op">|</span>_<span class="op">|</span> <span class="self">self</span>.<span class="ident">get_mut</span>().<span class="ident">seek</span>(<span class="ident">pos</span>)) } } <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> <span class="ident">Drop</span> <span class="kw">for</span> <span class="ident">BufWriter</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> { <span class="kw">fn</span> <span class="ident">drop</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) { <span class="kw">if</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">is_some</span>() <span class="op">&&</span> <span class="op">!</span><span class="self">self</span>.<span class="ident">panicked</span> { <span class="comment">// dtors should not panic, so we ignore a failed flush</span> <span class="kw">let</span> <span class="ident">_r</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">flush_buf</span>(); } } } <span class="kw">impl</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> <span class="ident">IntoInnerError</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> { <span class="doccomment">/// Returns the error which caused the call to `into_inner()` to fail.</span> <span class="doccomment">///</span> <span class="doccomment">/// This error was returned when attempting to write the internal buffer.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```no_run</span> <span class="doccomment">/// use std::io::BufWriter;</span> <span class="doccomment">/// use std::net::TcpStream;</span> <span class="doccomment">///</span> <span class="doccomment">/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());</span> <span class="doccomment">///</span> <span class="doccomment">/// // do stuff with the stream</span> <span class="doccomment">///</span> <span class="doccomment">/// // we want to get our `TcpStream` back, so let's try:</span> <span class="doccomment">///</span> <span class="doccomment">/// let stream = match stream.into_inner() {</span> <span class="doccomment">/// Ok(s) => s,</span> <span class="doccomment">/// Err(e) => {</span> <span class="doccomment">/// // Here, e is an IntoInnerError, let's log the inner error.</span> <span class="doccomment">/// //</span> <span class="doccomment">/// // We'll just 'log' to stdout for this example.</span> <span class="doccomment">/// println!("{}", e.error());</span> <span class="doccomment">///</span> <span class="doccomment">/// panic!("An unexpected error occurred.");</span> <span class="doccomment">/// }</span> <span class="doccomment">/// };</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">error</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="ident">Error</span> { <span class="kw-2">&</span><span class="self">self</span>.<span class="number">1</span> } <span class="doccomment">/// Returns the buffered writer instance which generated the error.</span> <span class="doccomment">///</span> <span class="doccomment">/// The returned object can be used for error recovery, such as</span> <span class="doccomment">/// re-inspecting the buffer.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```no_run</span> <span class="doccomment">/// use std::io::BufWriter;</span> <span class="doccomment">/// use std::net::TcpStream;</span> <span class="doccomment">///</span> <span class="doccomment">/// let mut stream = BufWriter::new(TcpStream::connect("127.0.0.1:34254").unwrap());</span> <span class="doccomment">///</span> <span class="doccomment">/// // do stuff with the stream</span> <span class="doccomment">///</span> <span class="doccomment">/// // we want to get our `TcpStream` back, so let's try:</span> <span class="doccomment">///</span> <span class="doccomment">/// let stream = match stream.into_inner() {</span> <span class="doccomment">/// Ok(s) => s,</span> <span class="doccomment">/// Err(e) => {</span> <span class="doccomment">/// // Here, e is an IntoInnerError, let's re-examine the buffer:</span> <span class="doccomment">/// let buffer = e.into_inner();</span> <span class="doccomment">///</span> <span class="doccomment">/// // do stuff to try to recover</span> <span class="doccomment">///</span> <span class="doccomment">/// // afterwards, let's just return the stream</span> <span class="doccomment">/// buffer.into_inner().unwrap()</span> <span class="doccomment">/// }</span> <span class="doccomment">/// };</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">into_inner</span>(<span class="self">self</span>) <span class="op">-></span> <span class="ident">W</span> { <span class="self">self</span>.<span class="number">0</span> } } <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> <span class="ident">From</span><span class="op"><</span><span class="ident">IntoInnerError</span><span class="op"><</span><span class="ident">W</span><span class="op">>></span> <span class="kw">for</span> <span class="ident">Error</span> { <span class="kw">fn</span> <span class="ident">from</span>(<span class="ident">iie</span>: <span class="ident">IntoInnerError</span><span class="op"><</span><span class="ident">W</span><span class="op">></span>) <span class="op">-></span> <span class="ident">Error</span> { <span class="ident">iie</span>.<span class="number">1</span> } } <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Send</span> <span class="op">+</span> <span class="ident">fmt</span>::<span class="ident">Debug</span><span class="op">></span> <span class="ident">error</span>::<span class="ident">Error</span> <span class="kw">for</span> <span class="ident">IntoInnerError</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> { <span class="kw">fn</span> <span class="ident">description</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="ident">str</span> { <span class="ident">error</span>::<span class="ident">Error</span>::<span class="ident">description</span>(<span class="self">self</span>.<span class="ident">error</span>()) } } <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> <span class="ident">fmt</span>::<span class="ident">Display</span> <span class="kw">for</span> <span class="ident">IntoInnerError</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> { <span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt</span>::<span class="ident">Formatter</span>) <span class="op">-></span> <span class="ident">fmt</span>::<span class="prelude-ty">Result</span> { <span class="self">self</span>.<span class="ident">error</span>().<span class="ident">fmt</span>(<span class="ident">f</span>) } } <span class="doccomment">/// Wraps a writer and buffers output to it, flushing whenever a newline</span> <span class="doccomment">/// (`0x0a`, `'\n'`) is detected.</span> <span class="doccomment">///</span> <span class="doccomment">/// The [`BufWriter`][bufwriter] struct wraps a writer and buffers its output.</span> <span class="doccomment">/// But it only does this batched write when it goes out of scope, or when the</span> <span class="doccomment">/// internal buffer is full. Sometimes, you'd prefer to write each line as it's</span> <span class="doccomment">/// completed, rather than the entire buffer at once. Enter `LineWriter`. It</span> <span class="doccomment">/// does exactly that.</span> <span class="doccomment">///</span> <span class="doccomment">/// Like [`BufWriter`], a `LineWriter`’s buffer will also be flushed when the</span> <span class="doccomment">/// `LineWriter` goes out of scope or when its internal buffer is full.</span> <span class="doccomment">///</span> <span class="doccomment">/// [bufwriter]: struct.BufWriter.html</span> <span class="doccomment">///</span> <span class="doccomment">/// If there's still a partial line in the buffer when the `LineWriter` is</span> <span class="doccomment">/// dropped, it will flush those contents.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// We can use `LineWriter` to write one line at a time, significantly</span> <span class="doccomment">/// reducing the number of actual writes to the file.</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// use std::fs::File;</span> <span class="doccomment">/// use std::io::prelude::*;</span> <span class="doccomment">/// use std::io::LineWriter;</span> <span class="doccomment">///</span> <span class="doccomment">/// # fn foo() -> std::io::Result<()> {</span> <span class="doccomment">/// let road_not_taken = b"I shall be telling this with a sigh</span> <span class="doccomment">/// Somewhere ages and ages hence:</span> <span class="doccomment">/// Two roads diverged in a wood, and I -</span> <span class="doccomment">/// I took the one less traveled by,</span> <span class="doccomment">/// And that has made all the difference.";</span> <span class="doccomment">///</span> <span class="doccomment">/// let file = File::create("poem.txt")?;</span> <span class="doccomment">/// let mut file = LineWriter::new(file);</span> <span class="doccomment">///</span> <span class="doccomment">/// for &byte in road_not_taken.iter() {</span> <span class="doccomment">/// file.write(&[byte]).unwrap();</span> <span class="doccomment">/// }</span> <span class="doccomment">///</span> <span class="doccomment">/// // let's check we did the right thing.</span> <span class="doccomment">/// let mut file = File::open("poem.txt")?;</span> <span class="doccomment">/// let mut contents = String::new();</span> <span class="doccomment">///</span> <span class="doccomment">/// file.read_to_string(&mut contents)?;</span> <span class="doccomment">///</span> <span class="doccomment">/// assert_eq!(contents.as_bytes(), &road_not_taken[..]);</span> <span class="doccomment">/// # Ok(())</span> <span class="doccomment">/// # }</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">LineWriter</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> { <span class="ident">inner</span>: <span class="ident">BufWriter</span><span class="op"><</span><span class="ident">W</span><span class="op">></span>, <span class="ident">need_flush</span>: <span class="ident">bool</span>, } <span class="kw">impl</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> <span class="ident">LineWriter</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> { <span class="doccomment">/// Creates a new `LineWriter`.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// use std::fs::File;</span> <span class="doccomment">/// use std::io::LineWriter;</span> <span class="doccomment">///</span> <span class="doccomment">/// # fn foo() -> std::io::Result<()> {</span> <span class="doccomment">/// let file = File::create("poem.txt")?;</span> <span class="doccomment">/// let file = LineWriter::new(file);</span> <span class="doccomment">/// # Ok(())</span> <span class="doccomment">/// # }</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">inner</span>: <span class="ident">W</span>) <span class="op">-></span> <span class="ident">LineWriter</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> { <span class="comment">// Lines typically aren't that long, don't use a giant buffer</span> <span class="ident">LineWriter</span>::<span class="ident">with_capacity</span>(<span class="number">1024</span>, <span class="ident">inner</span>) } <span class="doccomment">/// Creates a new `LineWriter` with a specified capacity for the internal</span> <span class="doccomment">/// buffer.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// use std::fs::File;</span> <span class="doccomment">/// use std::io::LineWriter;</span> <span class="doccomment">///</span> <span class="doccomment">/// # fn foo() -> std::io::Result<()> {</span> <span class="doccomment">/// let file = File::create("poem.txt")?;</span> <span class="doccomment">/// let file = LineWriter::with_capacity(100, file);</span> <span class="doccomment">/// # Ok(())</span> <span class="doccomment">/// # }</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">with_capacity</span>(<span class="ident">cap</span>: <span class="ident">usize</span>, <span class="ident">inner</span>: <span class="ident">W</span>) <span class="op">-></span> <span class="ident">LineWriter</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> { <span class="ident">LineWriter</span> { <span class="ident">inner</span>: <span class="ident">BufWriter</span>::<span class="ident">with_capacity</span>(<span class="ident">cap</span>, <span class="ident">inner</span>), <span class="ident">need_flush</span>: <span class="bool-val">false</span>, } } <span class="doccomment">/// Gets a reference to the underlying writer.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// use std::fs::File;</span> <span class="doccomment">/// use std::io::LineWriter;</span> <span class="doccomment">///</span> <span class="doccomment">/// # fn foo() -> std::io::Result<()> {</span> <span class="doccomment">/// let file = File::create("poem.txt")?;</span> <span class="doccomment">/// let file = LineWriter::new(file);</span> <span class="doccomment">///</span> <span class="doccomment">/// let reference = file.get_ref();</span> <span class="doccomment">/// # Ok(())</span> <span class="doccomment">/// # }</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">get_ref</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="ident">W</span> { <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">get_ref</span>() } <span class="doccomment">/// Gets a mutable reference to the underlying writer.</span> <span class="doccomment">///</span> <span class="doccomment">/// Caution must be taken when calling methods on the mutable reference</span> <span class="doccomment">/// returned as extra writes could corrupt the output stream.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// use std::fs::File;</span> <span class="doccomment">/// use std::io::LineWriter;</span> <span class="doccomment">///</span> <span class="doccomment">/// # fn foo() -> std::io::Result<()> {</span> <span class="doccomment">/// let file = File::create("poem.txt")?;</span> <span class="doccomment">/// let mut file = LineWriter::new(file);</span> <span class="doccomment">///</span> <span class="doccomment">/// // we can use reference just like file</span> <span class="doccomment">/// let reference = file.get_mut();</span> <span class="doccomment">/// # Ok(())</span> <span class="doccomment">/// # }</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">get_mut</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">W</span> { <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">get_mut</span>() } <span class="doccomment">/// Unwraps this `LineWriter`, returning the underlying writer.</span> <span class="doccomment">///</span> <span class="doccomment">/// The internal buffer is written out before returning the writer.</span> <span class="doccomment">///</span> <span class="comment">// # Errors</span> <span class="doccomment">///</span> <span class="doccomment">/// An `Err` will be returned if an error occurs while flushing the buffer.</span> <span class="doccomment">///</span> <span class="doccomment">/// # Examples</span> <span class="doccomment">///</span> <span class="doccomment">/// ```</span> <span class="doccomment">/// use std::fs::File;</span> <span class="doccomment">/// use std::io::LineWriter;</span> <span class="doccomment">///</span> <span class="doccomment">/// # fn foo() -> std::io::Result<()> {</span> <span class="doccomment">/// let file = File::create("poem.txt")?;</span> <span class="doccomment">///</span> <span class="doccomment">/// let writer: LineWriter<File> = LineWriter::new(file);</span> <span class="doccomment">///</span> <span class="doccomment">/// let file: File = writer.into_inner()?;</span> <span class="doccomment">/// # Ok(())</span> <span class="doccomment">/// # }</span> <span class="doccomment">/// ```</span> <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">into_inner</span>(<span class="self">self</span>) <span class="op">-></span> <span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">W</span>, <span class="ident">IntoInnerError</span><span class="op"><</span><span class="ident">LineWriter</span><span class="op"><</span><span class="ident">W</span><span class="op">>></span><span class="op">></span> { <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">into_inner</span>().<span class="ident">map_err</span>(<span class="op">|</span><span class="ident">IntoInnerError</span>(<span class="ident">buf</span>, <span class="ident">e</span>)<span class="op">|</span> { <span class="ident">IntoInnerError</span>(<span class="ident">LineWriter</span> { <span class="ident">inner</span>: <span class="ident">buf</span>, <span class="ident">need_flush</span>: <span class="bool-val">false</span>, }, <span class="ident">e</span>) }) } } <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> <span class="ident">Write</span> <span class="kw">for</span> <span class="ident">LineWriter</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> { <span class="kw">fn</span> <span class="ident">write</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">buf</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>]) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> { <span class="kw">if</span> <span class="self">self</span>.<span class="ident">need_flush</span> { <span class="self">self</span>.<span class="ident">flush</span>()<span class="question-mark">?</span>; } <span class="comment">// Find the last newline character in the buffer provided. If found then</span> <span class="comment">// we're going to write all the data up to that point and then flush,</span> <span class="comment">// otherewise we just write the whole block to the underlying writer.</span> <span class="kw">let</span> <span class="ident">i</span> <span class="op">=</span> <span class="kw">match</span> <span class="ident">memchr</span>::<span class="ident">memrchr</span>(<span class="string">b'\n'</span>, <span class="ident">buf</span>) { <span class="prelude-val">Some</span>(<span class="ident">i</span>) <span class="op">=></span> <span class="ident">i</span>, <span class="prelude-val">None</span> <span class="op">=></span> <span class="kw">return</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">write</span>(<span class="ident">buf</span>), }; <span class="comment">// Ok, we're going to write a partial amount of the data given first</span> <span class="comment">// followed by flushing the newline. After we've successfully written</span> <span class="comment">// some data then we *must* report that we wrote that data, so future</span> <span class="comment">// errors are ignored. We set our internal `need_flush` flag, though, in</span> <span class="comment">// case flushing fails and we need to try it first next time.</span> <span class="kw">let</span> <span class="ident">n</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">write</span>(<span class="kw-2">&</span><span class="ident">buf</span>[..<span class="ident">i</span> <span class="op">+</span> <span class="number">1</span>])<span class="question-mark">?</span>; <span class="self">self</span>.<span class="ident">need_flush</span> <span class="op">=</span> <span class="bool-val">true</span>; <span class="kw">if</span> <span class="self">self</span>.<span class="ident">flush</span>().<span class="ident">is_err</span>() <span class="op">||</span> <span class="ident">n</span> <span class="op">!=</span> <span class="ident">i</span> <span class="op">+</span> <span class="number">1</span> { <span class="kw">return</span> <span class="prelude-val">Ok</span>(<span class="ident">n</span>) } <span class="comment">// At this point we successfully wrote `i + 1` bytes and flushed it out,</span> <span class="comment">// meaning that the entire line is now flushed out on the screen. While</span> <span class="comment">// we can attempt to finish writing the rest of the data provided.</span> <span class="comment">// Remember though that we ignore errors here as we've successfully</span> <span class="comment">// written data, so we need to report that.</span> <span class="kw">match</span> <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">write</span>(<span class="kw-2">&</span><span class="ident">buf</span>[<span class="ident">i</span> <span class="op">+</span> <span class="number">1</span>..]) { <span class="prelude-val">Ok</span>(<span class="ident">i</span>) <span class="op">=></span> <span class="prelude-val">Ok</span>(<span class="ident">n</span> <span class="op">+</span> <span class="ident">i</span>), <span class="prelude-val">Err</span>(_) <span class="op">=></span> <span class="prelude-val">Ok</span>(<span class="ident">n</span>), } } <span class="kw">fn</span> <span class="ident">flush</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> { <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">flush</span>()<span class="question-mark">?</span>; <span class="self">self</span>.<span class="ident">need_flush</span> <span class="op">=</span> <span class="bool-val">false</span>; <span class="prelude-val">Ok</span>(()) } } <span class="attribute">#[<span class="ident">stable</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"rust1"</span>, <span class="ident">since</span> <span class="op">=</span> <span class="string">"1.0.0"</span>)]</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">W</span>: <span class="ident">Write</span><span class="op">></span> <span class="ident">fmt</span>::<span class="ident">Debug</span> <span class="kw">for</span> <span class="ident">LineWriter</span><span class="op"><</span><span class="ident">W</span><span class="op">></span> <span class="kw">where</span> <span class="ident">W</span>: <span class="ident">fmt</span>::<span class="ident">Debug</span> { <span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">fmt</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt</span>::<span class="ident">Formatter</span>) <span class="op">-></span> <span class="ident">fmt</span>::<span class="prelude-ty">Result</span> { <span class="ident">fmt</span>.<span class="ident">debug_struct</span>(<span class="string">"LineWriter"</span>) .<span class="ident">field</span>(<span class="string">"writer"</span>, <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">inner</span>) .<span class="ident">field</span>(<span class="string">"buffer"</span>, <span class="kw-2">&</span><span class="macro">format_args</span><span class="macro">!</span>(<span class="string">"{}/{}"</span>, <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">buf</span>.<span class="ident">len</span>(), <span class="self">self</span>.<span class="ident">inner</span>.<span class="ident">buf</span>.<span class="ident">capacity</span>())) .<span class="ident">finish</span>() } } <span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">test</span>)]</span> <span class="kw">mod</span> <span class="ident">tests</span> { <span class="kw">use</span> <span class="ident">io</span>::<span class="ident">prelude</span>::<span class="kw-2">*</span>; <span class="kw">use</span> <span class="ident">io</span>::{<span class="self">self</span>, <span class="ident">BufReader</span>, <span class="ident">BufWriter</span>, <span class="ident">LineWriter</span>, <span class="ident">SeekFrom</span>}; <span class="kw">use</span> <span class="ident">sync</span>::<span class="ident">atomic</span>::{<span class="ident">AtomicUsize</span>, <span class="ident">Ordering</span>}; <span class="kw">use</span> <span class="ident">thread</span>; <span class="kw">use</span> <span class="ident">test</span>; <span class="doccomment">/// A dummy reader intended at testing short-reads propagation.</span> <span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">ShortReader</span> { <span class="ident">lengths</span>: <span class="ident">Vec</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span>, } <span class="kw">impl</span> <span class="ident">Read</span> <span class="kw">for</span> <span class="ident">ShortReader</span> { <span class="kw">fn</span> <span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, _: <span class="kw-2">&</span><span class="kw-2">mut</span> [<span class="ident">u8</span>]) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> { <span class="kw">if</span> <span class="self">self</span>.<span class="ident">lengths</span>.<span class="ident">is_empty</span>() { <span class="prelude-val">Ok</span>(<span class="number">0</span>) } <span class="kw">else</span> { <span class="prelude-val">Ok</span>(<span class="self">self</span>.<span class="ident">lengths</span>.<span class="ident">remove</span>(<span class="number">0</span>)) } } } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">test_buffered_reader</span>() { <span class="kw">let</span> <span class="ident">inner</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>] <span class="op">=</span> <span class="kw-2">&</span>[<span class="number">5</span>, <span class="number">6</span>, <span class="number">7</span>, <span class="number">0</span>, <span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>]; <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">reader</span> <span class="op">=</span> <span class="ident">BufReader</span>::<span class="ident">with_capacity</span>(<span class="number">2</span>, <span class="ident">inner</span>); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buf</span> <span class="op">=</span> [<span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>]; <span class="kw">let</span> <span class="ident">nread</span> <span class="op">=</span> <span class="ident">reader</span>.<span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buf</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">nread</span>.<span class="ident">unwrap</span>(), <span class="number">3</span>); <span class="kw">let</span> <span class="ident">b</span>: <span class="kw-2">&</span>[_] <span class="op">=</span> <span class="kw-2">&</span>[<span class="number">5</span>, <span class="number">6</span>, <span class="number">7</span>]; <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">buf</span>, <span class="ident">b</span>); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buf</span> <span class="op">=</span> [<span class="number">0</span>, <span class="number">0</span>]; <span class="kw">let</span> <span class="ident">nread</span> <span class="op">=</span> <span class="ident">reader</span>.<span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buf</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">nread</span>.<span class="ident">unwrap</span>(), <span class="number">2</span>); <span class="kw">let</span> <span class="ident">b</span>: <span class="kw-2">&</span>[_] <span class="op">=</span> <span class="kw-2">&</span>[<span class="number">0</span>, <span class="number">1</span>]; <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">buf</span>, <span class="ident">b</span>); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buf</span> <span class="op">=</span> [<span class="number">0</span>]; <span class="kw">let</span> <span class="ident">nread</span> <span class="op">=</span> <span class="ident">reader</span>.<span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buf</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">nread</span>.<span class="ident">unwrap</span>(), <span class="number">1</span>); <span class="kw">let</span> <span class="ident">b</span>: <span class="kw-2">&</span>[_] <span class="op">=</span> <span class="kw-2">&</span>[<span class="number">2</span>]; <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">buf</span>, <span class="ident">b</span>); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buf</span> <span class="op">=</span> [<span class="number">0</span>, <span class="number">0</span>, <span class="number">0</span>]; <span class="kw">let</span> <span class="ident">nread</span> <span class="op">=</span> <span class="ident">reader</span>.<span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buf</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">nread</span>.<span class="ident">unwrap</span>(), <span class="number">1</span>); <span class="kw">let</span> <span class="ident">b</span>: <span class="kw-2">&</span>[_] <span class="op">=</span> <span class="kw-2">&</span>[<span class="number">3</span>, <span class="number">0</span>, <span class="number">0</span>]; <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">buf</span>, <span class="ident">b</span>); <span class="kw">let</span> <span class="ident">nread</span> <span class="op">=</span> <span class="ident">reader</span>.<span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buf</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">nread</span>.<span class="ident">unwrap</span>(), <span class="number">1</span>); <span class="kw">let</span> <span class="ident">b</span>: <span class="kw-2">&</span>[_] <span class="op">=</span> <span class="kw-2">&</span>[<span class="number">4</span>, <span class="number">0</span>, <span class="number">0</span>]; <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">buf</span>, <span class="ident">b</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buf</span>).<span class="ident">unwrap</span>(), <span class="number">0</span>); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">test_buffered_reader_seek</span>() { <span class="kw">let</span> <span class="ident">inner</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>] <span class="op">=</span> <span class="kw-2">&</span>[<span class="number">5</span>, <span class="number">6</span>, <span class="number">7</span>, <span class="number">0</span>, <span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>]; <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">reader</span> <span class="op">=</span> <span class="ident">BufReader</span>::<span class="ident">with_capacity</span>(<span class="number">2</span>, <span class="ident">io</span>::<span class="ident">Cursor</span>::<span class="ident">new</span>(<span class="ident">inner</span>)); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">seek</span>(<span class="ident">SeekFrom</span>::<span class="ident">Start</span>(<span class="number">3</span>)).<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="number">3</span>)); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">fill_buf</span>().<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="kw-2">&</span>[<span class="number">0</span>, <span class="number">1</span>][..])); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">seek</span>(<span class="ident">SeekFrom</span>::<span class="ident">Current</span>(<span class="number">0</span>)).<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="number">3</span>)); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">fill_buf</span>().<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="kw-2">&</span>[<span class="number">0</span>, <span class="number">1</span>][..])); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">seek</span>(<span class="ident">SeekFrom</span>::<span class="ident">Current</span>(<span class="number">1</span>)).<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="number">4</span>)); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">fill_buf</span>().<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="kw-2">&</span>[<span class="number">1</span>, <span class="number">2</span>][..])); <span class="ident">reader</span>.<span class="ident">consume</span>(<span class="number">1</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">seek</span>(<span class="ident">SeekFrom</span>::<span class="ident">Current</span>(<span class="op">-</span><span class="number">2</span>)).<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="number">3</span>)); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">test_buffered_reader_seek_relative</span>() { <span class="kw">let</span> <span class="ident">inner</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>] <span class="op">=</span> <span class="kw-2">&</span>[<span class="number">5</span>, <span class="number">6</span>, <span class="number">7</span>, <span class="number">0</span>, <span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>]; <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">reader</span> <span class="op">=</span> <span class="ident">BufReader</span>::<span class="ident">with_capacity</span>(<span class="number">2</span>, <span class="ident">io</span>::<span class="ident">Cursor</span>::<span class="ident">new</span>(<span class="ident">inner</span>)); <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">seek_relative</span>(<span class="number">3</span>).<span class="ident">is_ok</span>()); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">fill_buf</span>().<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="kw-2">&</span>[<span class="number">0</span>, <span class="number">1</span>][..])); <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">seek_relative</span>(<span class="number">0</span>).<span class="ident">is_ok</span>()); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">fill_buf</span>().<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="kw-2">&</span>[<span class="number">0</span>, <span class="number">1</span>][..])); <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">seek_relative</span>(<span class="number">1</span>).<span class="ident">is_ok</span>()); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">fill_buf</span>().<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="kw-2">&</span>[<span class="number">1</span>][..])); <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">seek_relative</span>(<span class="op">-</span><span class="number">1</span>).<span class="ident">is_ok</span>()); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">fill_buf</span>().<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="kw-2">&</span>[<span class="number">0</span>, <span class="number">1</span>][..])); <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">seek_relative</span>(<span class="number">2</span>).<span class="ident">is_ok</span>()); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">fill_buf</span>().<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="kw-2">&</span>[<span class="number">2</span>, <span class="number">3</span>][..])); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">test_buffered_reader_seek_underflow</span>() { <span class="comment">// gimmick reader that yields its position modulo 256 for each byte</span> <span class="kw">struct</span> <span class="ident">PositionReader</span> { <span class="ident">pos</span>: <span class="ident">u64</span> } <span class="kw">impl</span> <span class="ident">Read</span> <span class="kw">for</span> <span class="ident">PositionReader</span> { <span class="kw">fn</span> <span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">buf</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> [<span class="ident">u8</span>]) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> { <span class="kw">let</span> <span class="ident">len</span> <span class="op">=</span> <span class="ident">buf</span>.<span class="ident">len</span>(); <span class="kw">for</span> <span class="ident">x</span> <span class="kw">in</span> <span class="ident">buf</span> { <span class="kw-2">*</span><span class="ident">x</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">pos</span> <span class="kw">as</span> <span class="ident">u8</span>; <span class="self">self</span>.<span class="ident">pos</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">pos</span>.<span class="ident">wrapping_add</span>(<span class="number">1</span>); } <span class="prelude-val">Ok</span>(<span class="ident">len</span>) } } <span class="kw">impl</span> <span class="ident">Seek</span> <span class="kw">for</span> <span class="ident">PositionReader</span> { <span class="kw">fn</span> <span class="ident">seek</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">pos</span>: <span class="ident">SeekFrom</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">u64</span><span class="op">></span> { <span class="kw">match</span> <span class="ident">pos</span> { <span class="ident">SeekFrom</span>::<span class="ident">Start</span>(<span class="ident">n</span>) <span class="op">=></span> { <span class="self">self</span>.<span class="ident">pos</span> <span class="op">=</span> <span class="ident">n</span>; } <span class="ident">SeekFrom</span>::<span class="ident">Current</span>(<span class="ident">n</span>) <span class="op">=></span> { <span class="self">self</span>.<span class="ident">pos</span> <span class="op">=</span> <span class="self">self</span>.<span class="ident">pos</span>.<span class="ident">wrapping_add</span>(<span class="ident">n</span> <span class="kw">as</span> <span class="ident">u64</span>); } <span class="ident">SeekFrom</span>::<span class="ident">End</span>(<span class="ident">n</span>) <span class="op">=></span> { <span class="self">self</span>.<span class="ident">pos</span> <span class="op">=</span> <span class="ident">u64</span>::<span class="ident">max_value</span>().<span class="ident">wrapping_add</span>(<span class="ident">n</span> <span class="kw">as</span> <span class="ident">u64</span>); } } <span class="prelude-val">Ok</span>(<span class="self">self</span>.<span class="ident">pos</span>) } } <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">reader</span> <span class="op">=</span> <span class="ident">BufReader</span>::<span class="ident">with_capacity</span>(<span class="number">5</span>, <span class="ident">PositionReader</span> { <span class="ident">pos</span>: <span class="number">0</span> }); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">fill_buf</span>().<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="kw-2">&</span>[<span class="number">0</span>, <span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>][..])); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">seek</span>(<span class="ident">SeekFrom</span>::<span class="ident">End</span>(<span class="op">-</span><span class="number">5</span>)).<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="ident">u64</span>::<span class="ident">max_value</span>()<span class="op">-</span><span class="number">5</span>)); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">fill_buf</span>().<span class="ident">ok</span>().<span class="ident">map</span>(<span class="op">|</span><span class="ident">s</span><span class="op">|</span> <span class="ident">s</span>.<span class="ident">len</span>()), <span class="prelude-val">Some</span>(<span class="number">5</span>)); <span class="comment">// the following seek will require two underlying seeks</span> <span class="kw">let</span> <span class="ident">expected</span> <span class="op">=</span> <span class="number">9223372036854775802</span>; <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">seek</span>(<span class="ident">SeekFrom</span>::<span class="ident">Current</span>(<span class="ident">i64</span>::<span class="ident">min_value</span>())).<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="ident">expected</span>)); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">fill_buf</span>().<span class="ident">ok</span>().<span class="ident">map</span>(<span class="op">|</span><span class="ident">s</span><span class="op">|</span> <span class="ident">s</span>.<span class="ident">len</span>()), <span class="prelude-val">Some</span>(<span class="number">5</span>)); <span class="comment">// seeking to 0 should empty the buffer.</span> <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">seek</span>(<span class="ident">SeekFrom</span>::<span class="ident">Current</span>(<span class="number">0</span>)).<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="ident">expected</span>)); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">get_ref</span>().<span class="ident">pos</span>, <span class="ident">expected</span>); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">test_buffered_writer</span>() { <span class="kw">let</span> <span class="ident">inner</span> <span class="op">=</span> <span class="ident">Vec</span>::<span class="ident">new</span>(); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">writer</span> <span class="op">=</span> <span class="ident">BufWriter</span>::<span class="ident">with_capacity</span>(<span class="number">2</span>, <span class="ident">inner</span>); <span class="ident">writer</span>.<span class="ident">write</span>(<span class="kw-2">&</span>[<span class="number">0</span>, <span class="number">1</span>]).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">*</span><span class="ident">writer</span>.<span class="ident">get_ref</span>(), [<span class="number">0</span>, <span class="number">1</span>]); <span class="ident">writer</span>.<span class="ident">write</span>(<span class="kw-2">&</span>[<span class="number">2</span>]).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">*</span><span class="ident">writer</span>.<span class="ident">get_ref</span>(), [<span class="number">0</span>, <span class="number">1</span>]); <span class="ident">writer</span>.<span class="ident">write</span>(<span class="kw-2">&</span>[<span class="number">3</span>]).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">*</span><span class="ident">writer</span>.<span class="ident">get_ref</span>(), [<span class="number">0</span>, <span class="number">1</span>]); <span class="ident">writer</span>.<span class="ident">flush</span>().<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">*</span><span class="ident">writer</span>.<span class="ident">get_ref</span>(), [<span class="number">0</span>, <span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>]); <span class="ident">writer</span>.<span class="ident">write</span>(<span class="kw-2">&</span>[<span class="number">4</span>]).<span class="ident">unwrap</span>(); <span class="ident">writer</span>.<span class="ident">write</span>(<span class="kw-2">&</span>[<span class="number">5</span>]).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">*</span><span class="ident">writer</span>.<span class="ident">get_ref</span>(), [<span class="number">0</span>, <span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>]); <span class="ident">writer</span>.<span class="ident">write</span>(<span class="kw-2">&</span>[<span class="number">6</span>]).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">*</span><span class="ident">writer</span>.<span class="ident">get_ref</span>(), [<span class="number">0</span>, <span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>]); <span class="ident">writer</span>.<span class="ident">write</span>(<span class="kw-2">&</span>[<span class="number">7</span>, <span class="number">8</span>]).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">*</span><span class="ident">writer</span>.<span class="ident">get_ref</span>(), [<span class="number">0</span>, <span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>, <span class="number">6</span>, <span class="number">7</span>, <span class="number">8</span>]); <span class="ident">writer</span>.<span class="ident">write</span>(<span class="kw-2">&</span>[<span class="number">9</span>, <span class="number">10</span>, <span class="number">11</span>]).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">*</span><span class="ident">writer</span>.<span class="ident">get_ref</span>(), [<span class="number">0</span>, <span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>, <span class="number">6</span>, <span class="number">7</span>, <span class="number">8</span>, <span class="number">9</span>, <span class="number">10</span>, <span class="number">11</span>]); <span class="ident">writer</span>.<span class="ident">flush</span>().<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">*</span><span class="ident">writer</span>.<span class="ident">get_ref</span>(), [<span class="number">0</span>, <span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>, <span class="number">6</span>, <span class="number">7</span>, <span class="number">8</span>, <span class="number">9</span>, <span class="number">10</span>, <span class="number">11</span>]); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">test_buffered_writer_inner_flushes</span>() { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">w</span> <span class="op">=</span> <span class="ident">BufWriter</span>::<span class="ident">with_capacity</span>(<span class="number">3</span>, <span class="ident">Vec</span>::<span class="ident">new</span>()); <span class="ident">w</span>.<span class="ident">write</span>(<span class="kw-2">&</span>[<span class="number">0</span>, <span class="number">1</span>]).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">*</span><span class="ident">w</span>.<span class="ident">get_ref</span>(), []); <span class="kw">let</span> <span class="ident">w</span> <span class="op">=</span> <span class="ident">w</span>.<span class="ident">into_inner</span>().<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">w</span>, [<span class="number">0</span>, <span class="number">1</span>]); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">test_buffered_writer_seek</span>() { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">w</span> <span class="op">=</span> <span class="ident">BufWriter</span>::<span class="ident">with_capacity</span>(<span class="number">3</span>, <span class="ident">io</span>::<span class="ident">Cursor</span>::<span class="ident">new</span>(<span class="ident">Vec</span>::<span class="ident">new</span>())); <span class="ident">w</span>.<span class="ident">write_all</span>(<span class="kw-2">&</span>[<span class="number">0</span>, <span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>]).<span class="ident">unwrap</span>(); <span class="ident">w</span>.<span class="ident">write_all</span>(<span class="kw-2">&</span>[<span class="number">6</span>, <span class="number">7</span>]).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">w</span>.<span class="ident">seek</span>(<span class="ident">SeekFrom</span>::<span class="ident">Current</span>(<span class="number">0</span>)).<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="number">8</span>)); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">&</span><span class="ident">w</span>.<span class="ident">get_ref</span>().<span class="ident">get_ref</span>()[..], <span class="kw-2">&</span>[<span class="number">0</span>, <span class="number">1</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="number">4</span>, <span class="number">5</span>, <span class="number">6</span>, <span class="number">7</span>][..]); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">w</span>.<span class="ident">seek</span>(<span class="ident">SeekFrom</span>::<span class="ident">Start</span>(<span class="number">2</span>)).<span class="ident">ok</span>(), <span class="prelude-val">Some</span>(<span class="number">2</span>)); <span class="ident">w</span>.<span class="ident">write_all</span>(<span class="kw-2">&</span>[<span class="number">8</span>, <span class="number">9</span>]).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">&</span><span class="ident">w</span>.<span class="ident">into_inner</span>().<span class="ident">unwrap</span>().<span class="ident">into_inner</span>()[..], <span class="kw-2">&</span>[<span class="number">0</span>, <span class="number">1</span>, <span class="number">8</span>, <span class="number">9</span>, <span class="number">4</span>, <span class="number">5</span>, <span class="number">6</span>, <span class="number">7</span>]); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">test_read_until</span>() { <span class="kw">let</span> <span class="ident">inner</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>] <span class="op">=</span> <span class="kw-2">&</span>[<span class="number">0</span>, <span class="number">1</span>, <span class="number">2</span>, <span class="number">1</span>, <span class="number">0</span>]; <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">reader</span> <span class="op">=</span> <span class="ident">BufReader</span>::<span class="ident">with_capacity</span>(<span class="number">2</span>, <span class="ident">inner</span>); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">v</span> <span class="op">=</span> <span class="ident">Vec</span>::<span class="ident">new</span>(); <span class="ident">reader</span>.<span class="ident">read_until</span>(<span class="number">0</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">v</span>).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">v</span>, [<span class="number">0</span>]); <span class="ident">v</span>.<span class="ident">truncate</span>(<span class="number">0</span>); <span class="ident">reader</span>.<span class="ident">read_until</span>(<span class="number">2</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">v</span>).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">v</span>, [<span class="number">1</span>, <span class="number">2</span>]); <span class="ident">v</span>.<span class="ident">truncate</span>(<span class="number">0</span>); <span class="ident">reader</span>.<span class="ident">read_until</span>(<span class="number">1</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">v</span>).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">v</span>, [<span class="number">1</span>]); <span class="ident">v</span>.<span class="ident">truncate</span>(<span class="number">0</span>); <span class="ident">reader</span>.<span class="ident">read_until</span>(<span class="number">8</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">v</span>).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">v</span>, [<span class="number">0</span>]); <span class="ident">v</span>.<span class="ident">truncate</span>(<span class="number">0</span>); <span class="ident">reader</span>.<span class="ident">read_until</span>(<span class="number">9</span>, <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">v</span>).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">v</span>, []); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">test_line_buffer_fail_flush</span>() { <span class="comment">// Issue #32085</span> <span class="kw">struct</span> <span class="ident">FailFlushWriter</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span>(<span class="kw-2">&</span><span class="lifetime">'a</span> <span class="kw-2">mut</span> <span class="ident">Vec</span><span class="op"><</span><span class="ident">u8</span><span class="op">></span>); <span class="kw">impl</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> <span class="ident">Write</span> <span class="kw">for</span> <span class="ident">FailFlushWriter</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> { <span class="kw">fn</span> <span class="ident">write</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">buf</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>]) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> { <span class="self">self</span>.<span class="number">0</span>.<span class="ident">extend_from_slice</span>(<span class="ident">buf</span>); <span class="prelude-val">Ok</span>(<span class="ident">buf</span>.<span class="ident">len</span>()) } <span class="kw">fn</span> <span class="ident">flush</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> { <span class="prelude-val">Err</span>(<span class="ident">io</span>::<span class="ident">Error</span>::<span class="ident">new</span>(<span class="ident">io</span>::<span class="ident">ErrorKind</span>::<span class="ident">Other</span>, <span class="string">"flush failed"</span>)) } } <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buf</span> <span class="op">=</span> <span class="ident">Vec</span>::<span class="ident">new</span>(); { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">writer</span> <span class="op">=</span> <span class="ident">LineWriter</span>::<span class="ident">new</span>(<span class="ident">FailFlushWriter</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buf</span>)); <span class="kw">let</span> <span class="ident">to_write</span> <span class="op">=</span> <span class="string">b"abc\ndef"</span>; <span class="kw">if</span> <span class="kw">let</span> <span class="prelude-val">Ok</span>(<span class="ident">written</span>) <span class="op">=</span> <span class="ident">writer</span>.<span class="ident">write</span>(<span class="ident">to_write</span>) { <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">written</span> <span class="op"><</span> <span class="ident">to_write</span>.<span class="ident">len</span>(), <span class="string">"didn't flush on new line"</span>); <span class="comment">// PASS</span> <span class="kw">return</span>; } } <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">buf</span>.<span class="ident">is_empty</span>(), <span class="string">"write returned an error but wrote data"</span>); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">test_line_buffer</span>() { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">writer</span> <span class="op">=</span> <span class="ident">LineWriter</span>::<span class="ident">new</span>(<span class="ident">Vec</span>::<span class="ident">new</span>()); <span class="ident">writer</span>.<span class="ident">write</span>(<span class="kw-2">&</span>[<span class="number">0</span>]).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">*</span><span class="ident">writer</span>.<span class="ident">get_ref</span>(), []); <span class="ident">writer</span>.<span class="ident">write</span>(<span class="kw-2">&</span>[<span class="number">1</span>]).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">*</span><span class="ident">writer</span>.<span class="ident">get_ref</span>(), []); <span class="ident">writer</span>.<span class="ident">flush</span>().<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">*</span><span class="ident">writer</span>.<span class="ident">get_ref</span>(), [<span class="number">0</span>, <span class="number">1</span>]); <span class="ident">writer</span>.<span class="ident">write</span>(<span class="kw-2">&</span>[<span class="number">0</span>, <span class="string">b'\n'</span>, <span class="number">1</span>, <span class="string">b'\n'</span>, <span class="number">2</span>]).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">*</span><span class="ident">writer</span>.<span class="ident">get_ref</span>(), [<span class="number">0</span>, <span class="number">1</span>, <span class="number">0</span>, <span class="string">b'\n'</span>, <span class="number">1</span>, <span class="string">b'\n'</span>]); <span class="ident">writer</span>.<span class="ident">flush</span>().<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">*</span><span class="ident">writer</span>.<span class="ident">get_ref</span>(), [<span class="number">0</span>, <span class="number">1</span>, <span class="number">0</span>, <span class="string">b'\n'</span>, <span class="number">1</span>, <span class="string">b'\n'</span>, <span class="number">2</span>]); <span class="ident">writer</span>.<span class="ident">write</span>(<span class="kw-2">&</span>[<span class="number">3</span>, <span class="string">b'\n'</span>]).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="kw-2">*</span><span class="ident">writer</span>.<span class="ident">get_ref</span>(), [<span class="number">0</span>, <span class="number">1</span>, <span class="number">0</span>, <span class="string">b'\n'</span>, <span class="number">1</span>, <span class="string">b'\n'</span>, <span class="number">2</span>, <span class="number">3</span>, <span class="string">b'\n'</span>]); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">test_read_line</span>() { <span class="kw">let</span> <span class="ident">in_buf</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>] <span class="op">=</span> <span class="string">b"a\nb\nc"</span>; <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">reader</span> <span class="op">=</span> <span class="ident">BufReader</span>::<span class="ident">with_capacity</span>(<span class="number">2</span>, <span class="ident">in_buf</span>); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">s</span> <span class="op">=</span> <span class="ident">String</span>::<span class="ident">new</span>(); <span class="ident">reader</span>.<span class="ident">read_line</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">s</span>).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">s</span>, <span class="string">"a\n"</span>); <span class="ident">s</span>.<span class="ident">truncate</span>(<span class="number">0</span>); <span class="ident">reader</span>.<span class="ident">read_line</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">s</span>).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">s</span>, <span class="string">"b\n"</span>); <span class="ident">s</span>.<span class="ident">truncate</span>(<span class="number">0</span>); <span class="ident">reader</span>.<span class="ident">read_line</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">s</span>).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">s</span>, <span class="string">"c"</span>); <span class="ident">s</span>.<span class="ident">truncate</span>(<span class="number">0</span>); <span class="ident">reader</span>.<span class="ident">read_line</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">s</span>).<span class="ident">unwrap</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">s</span>, <span class="string">""</span>); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">test_lines</span>() { <span class="kw">let</span> <span class="ident">in_buf</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>] <span class="op">=</span> <span class="string">b"a\nb\nc"</span>; <span class="kw">let</span> <span class="ident">reader</span> <span class="op">=</span> <span class="ident">BufReader</span>::<span class="ident">with_capacity</span>(<span class="number">2</span>, <span class="ident">in_buf</span>); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">it</span> <span class="op">=</span> <span class="ident">reader</span>.<span class="ident">lines</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">it</span>.<span class="ident">next</span>().<span class="ident">unwrap</span>().<span class="ident">unwrap</span>(), <span class="string">"a"</span>.<span class="ident">to_string</span>()); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">it</span>.<span class="ident">next</span>().<span class="ident">unwrap</span>().<span class="ident">unwrap</span>(), <span class="string">"b"</span>.<span class="ident">to_string</span>()); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">it</span>.<span class="ident">next</span>().<span class="ident">unwrap</span>().<span class="ident">unwrap</span>(), <span class="string">"c"</span>.<span class="ident">to_string</span>()); <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">it</span>.<span class="ident">next</span>().<span class="ident">is_none</span>()); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">test_short_reads</span>() { <span class="kw">let</span> <span class="ident">inner</span> <span class="op">=</span> <span class="ident">ShortReader</span>{<span class="ident">lengths</span>: <span class="macro">vec</span><span class="macro">!</span>[<span class="number">0</span>, <span class="number">1</span>, <span class="number">2</span>, <span class="number">0</span>, <span class="number">1</span>, <span class="number">0</span>]}; <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">reader</span> <span class="op">=</span> <span class="ident">BufReader</span>::<span class="ident">new</span>(<span class="ident">inner</span>); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">buf</span> <span class="op">=</span> [<span class="number">0</span>, <span class="number">0</span>]; <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buf</span>).<span class="ident">unwrap</span>(), <span class="number">0</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buf</span>).<span class="ident">unwrap</span>(), <span class="number">1</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buf</span>).<span class="ident">unwrap</span>(), <span class="number">2</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buf</span>).<span class="ident">unwrap</span>(), <span class="number">0</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buf</span>).<span class="ident">unwrap</span>(), <span class="number">1</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buf</span>).<span class="ident">unwrap</span>(), <span class="number">0</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">read</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">buf</span>).<span class="ident">unwrap</span>(), <span class="number">0</span>); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">read_char_buffered</span>() { <span class="kw">let</span> <span class="ident">buf</span> <span class="op">=</span> [<span class="number">195</span>, <span class="number">159</span>]; <span class="kw">let</span> <span class="ident">reader</span> <span class="op">=</span> <span class="ident">BufReader</span>::<span class="ident">with_capacity</span>(<span class="number">1</span>, <span class="kw-2">&</span><span class="ident">buf</span>[..]); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">reader</span>.<span class="ident">chars</span>().<span class="ident">next</span>().<span class="ident">unwrap</span>().<span class="ident">unwrap</span>(), <span class="string">'ß'</span>); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">test_chars</span>() { <span class="kw">let</span> <span class="ident">buf</span> <span class="op">=</span> [<span class="number">195</span>, <span class="number">159</span>, <span class="string">b'a'</span>]; <span class="kw">let</span> <span class="ident">reader</span> <span class="op">=</span> <span class="ident">BufReader</span>::<span class="ident">with_capacity</span>(<span class="number">1</span>, <span class="kw-2">&</span><span class="ident">buf</span>[..]); <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">it</span> <span class="op">=</span> <span class="ident">reader</span>.<span class="ident">chars</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">it</span>.<span class="ident">next</span>().<span class="ident">unwrap</span>().<span class="ident">unwrap</span>(), <span class="string">'ß'</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">it</span>.<span class="ident">next</span>().<span class="ident">unwrap</span>().<span class="ident">unwrap</span>(), <span class="string">'a'</span>); <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">it</span>.<span class="ident">next</span>().<span class="ident">is_none</span>()); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="attribute">#[<span class="ident">should_panic</span>]</span> <span class="kw">fn</span> <span class="ident">dont_panic_in_drop_on_panicked_flush</span>() { <span class="kw">struct</span> <span class="ident">FailFlushWriter</span>; <span class="kw">impl</span> <span class="ident">Write</span> <span class="kw">for</span> <span class="ident">FailFlushWriter</span> { <span class="kw">fn</span> <span class="ident">write</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">buf</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>]) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> { <span class="prelude-val">Ok</span>(<span class="ident">buf</span>.<span class="ident">len</span>()) } <span class="kw">fn</span> <span class="ident">flush</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> { <span class="prelude-val">Err</span>(<span class="ident">io</span>::<span class="ident">Error</span>::<span class="ident">last_os_error</span>()) } } <span class="kw">let</span> <span class="ident">writer</span> <span class="op">=</span> <span class="ident">FailFlushWriter</span>; <span class="kw">let</span> <span class="ident">_writer</span> <span class="op">=</span> <span class="ident">BufWriter</span>::<span class="ident">new</span>(<span class="ident">writer</span>); <span class="comment">// If writer panics *again* due to the flush error then the process will</span> <span class="comment">// abort.</span> <span class="macro">panic</span><span class="macro">!</span>(); } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="attribute">#[<span class="ident">cfg_attr</span>(<span class="ident">target_os</span> <span class="op">=</span> <span class="string">"emscripten"</span>, <span class="ident">ignore</span>)]</span> <span class="kw">fn</span> <span class="ident">panic_in_write_doesnt_flush_in_drop</span>() { <span class="kw">static</span> <span class="ident">WRITES</span>: <span class="ident">AtomicUsize</span> <span class="op">=</span> <span class="ident">AtomicUsize</span>::<span class="ident">new</span>(<span class="number">0</span>); <span class="kw">struct</span> <span class="ident">PanicWriter</span>; <span class="kw">impl</span> <span class="ident">Write</span> <span class="kw">for</span> <span class="ident">PanicWriter</span> { <span class="kw">fn</span> <span class="ident">write</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, _: <span class="kw-2">&</span>[<span class="ident">u8</span>]) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> { <span class="ident">WRITES</span>.<span class="ident">fetch_add</span>(<span class="number">1</span>, <span class="ident">Ordering</span>::<span class="ident">SeqCst</span>); <span class="macro">panic</span><span class="macro">!</span>(); } <span class="kw">fn</span> <span class="ident">flush</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> { <span class="prelude-val">Ok</span>(()) } } <span class="ident">thread</span>::<span class="ident">spawn</span>(<span class="op">||</span> { <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">writer</span> <span class="op">=</span> <span class="ident">BufWriter</span>::<span class="ident">new</span>(<span class="ident">PanicWriter</span>); <span class="kw">let</span> _ <span class="op">=</span> <span class="ident">writer</span>.<span class="ident">write</span>(<span class="string">b"hello world"</span>); <span class="kw">let</span> _ <span class="op">=</span> <span class="ident">writer</span>.<span class="ident">flush</span>(); }).<span class="ident">join</span>().<span class="ident">unwrap_err</span>(); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">WRITES</span>.<span class="ident">load</span>(<span class="ident">Ordering</span>::<span class="ident">SeqCst</span>), <span class="number">1</span>); } <span class="attribute">#[<span class="ident">bench</span>]</span> <span class="kw">fn</span> <span class="ident">bench_buffered_reader</span>(<span class="ident">b</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">test</span>::<span class="ident">Bencher</span>) { <span class="ident">b</span>.<span class="ident">iter</span>(<span class="op">||</span> { <span class="ident">BufReader</span>::<span class="ident">new</span>(<span class="ident">io</span>::<span class="ident">empty</span>()) }); } <span class="attribute">#[<span class="ident">bench</span>]</span> <span class="kw">fn</span> <span class="ident">bench_buffered_writer</span>(<span class="ident">b</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">test</span>::<span class="ident">Bencher</span>) { <span class="ident">b</span>.<span class="ident">iter</span>(<span class="op">||</span> { <span class="ident">BufWriter</span>::<span class="ident">new</span>(<span class="ident">io</span>::<span class="ident">sink</span>()) }); } <span class="kw">struct</span> <span class="ident">AcceptOneThenFail</span> { <span class="ident">written</span>: <span class="ident">bool</span>, <span class="ident">flushed</span>: <span class="ident">bool</span>, } <span class="kw">impl</span> <span class="ident">Write</span> <span class="kw">for</span> <span class="ident">AcceptOneThenFail</span> { <span class="kw">fn</span> <span class="ident">write</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">data</span>: <span class="kw-2">&</span>[<span class="ident">u8</span>]) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span><span class="ident">usize</span><span class="op">></span> { <span class="kw">if</span> <span class="op">!</span><span class="self">self</span>.<span class="ident">written</span> { <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">data</span>, <span class="string">b"a\nb\n"</span>); <span class="self">self</span>.<span class="ident">written</span> <span class="op">=</span> <span class="bool-val">true</span>; <span class="prelude-val">Ok</span>(<span class="ident">data</span>.<span class="ident">len</span>()) } <span class="kw">else</span> { <span class="prelude-val">Err</span>(<span class="ident">io</span>::<span class="ident">Error</span>::<span class="ident">new</span>(<span class="ident">io</span>::<span class="ident">ErrorKind</span>::<span class="ident">NotFound</span>, <span class="string">"test"</span>)) } } <span class="kw">fn</span> <span class="ident">flush</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="ident">io</span>::<span class="prelude-ty">Result</span><span class="op"><</span>()<span class="op">></span> { <span class="macro">assert</span><span class="macro">!</span>(<span class="self">self</span>.<span class="ident">written</span>); <span class="macro">assert</span><span class="macro">!</span>(<span class="op">!</span><span class="self">self</span>.<span class="ident">flushed</span>); <span class="self">self</span>.<span class="ident">flushed</span> <span class="op">=</span> <span class="bool-val">true</span>; <span class="prelude-val">Err</span>(<span class="ident">io</span>::<span class="ident">Error</span>::<span class="ident">new</span>(<span class="ident">io</span>::<span class="ident">ErrorKind</span>::<span class="ident">Other</span>, <span class="string">"test"</span>)) } } <span class="attribute">#[<span class="ident">test</span>]</span> <span class="kw">fn</span> <span class="ident">erroneous_flush_retried</span>() { <span class="kw">let</span> <span class="ident">a</span> <span class="op">=</span> <span class="ident">AcceptOneThenFail</span> { <span class="ident">written</span>: <span class="bool-val">false</span>, <span class="ident">flushed</span>: <span class="bool-val">false</span>, }; <span class="kw">let</span> <span class="kw-2">mut</span> <span class="ident">l</span> <span class="op">=</span> <span class="ident">LineWriter</span>::<span class="ident">new</span>(<span class="ident">a</span>); <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">l</span>.<span class="ident">write</span>(<span class="string">b"a\nb\na"</span>).<span class="ident">unwrap</span>(), <span class="number">4</span>); <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">l</span>.<span class="ident">get_ref</span>().<span class="ident">written</span>); <span class="macro">assert</span><span class="macro">!</span>(<span class="ident">l</span>.<span class="ident">get_ref</span>().<span class="ident">flushed</span>); <span class="ident">l</span>.<span class="ident">get_mut</span>().<span class="ident">flushed</span> <span class="op">=</span> <span class="bool-val">false</span>; <span class="macro">assert_eq</span><span class="macro">!</span>(<span class="ident">l</span>.<span class="ident">write</span>(<span class="string">b"a"</span>).<span class="ident">unwrap_err</span>().<span class="ident">kind</span>(), <span class="ident">io</span>::<span class="ident">ErrorKind</span>::<span class="ident">Other</span>) } } </pre> </section> <section id='search' class="content hidden"></section> <section class="footer"></section> <aside id="help" class="hidden"> <div> <h1 class="hidden">Help</h1> <div class="shortcuts"> <h2>Keyboard Shortcuts</h2> <dl> <dt><kbd>?</kbd></dt> <dd>Show this help dialog</dd> <dt><kbd>S</kbd></dt> <dd>Focus the search field</dd> <dt><kbd>↑</kbd></dt> <dd>Move up in search results</dd> <dt><kbd>↓</kbd></dt> <dd>Move down in search results</dd> <dt><kbd>↹</kbd></dt> <dd>Switch tab</dd> <dt><kbd>⏎</kbd></dt> <dd>Go to active search result</dd> <dt><kbd>+</kbd></dt> <dd>Expand all sections</dd> <dt><kbd>-</kbd></dt> <dd>Collapse all sections</dd> </dl> </div> <div class="infos"> <h2>Search Tricks</h2> <p> Prefix searches with a type followed by a colon (e.g. <code>fn:</code>) to restrict the search to a given type. </p> <p> Accepted types are: <code>fn</code>, <code>mod</code>, <code>struct</code>, <code>enum</code>, <code>trait</code>, <code>type</code>, <code>macro</code>, and <code>const</code>. </p> <p> Search functions by type signature (e.g. <code>vec -> usize</code> or <code>* -> vec</code>) </p> </div> </div> </aside> <script> window.rootPath = "../../../"; 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