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<pre><a name="line-1"></a><span class='hs-comment'>{- arch-tag: HVIO main file
<a name="line-2"></a>Copyright (C) 2004-2006 John Goerzen <jgoerzen@complete.org>
<a name="line-3"></a>
<a name="line-4"></a>This program is free software; you can redistribute it and/or modify
<a name="line-5"></a>it under the terms of the GNU General Public License as published by
<a name="line-6"></a>the Free Software Foundation; either version 2 of the License, or
<a name="line-7"></a>(at your option) any later version.
<a name="line-8"></a>
<a name="line-9"></a>This program is distributed in the hope that it will be useful,
<a name="line-10"></a>but WITHOUT ANY WARRANTY; without even the implied warranty of
<a name="line-11"></a>MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
<a name="line-12"></a>GNU General Public License for more details.
<a name="line-13"></a>
<a name="line-14"></a>You should have received a copy of the GNU General Public License
<a name="line-15"></a>along with this program; if not, write to the Free Software
<a name="line-16"></a>Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
<a name="line-17"></a>-}</span>
<a name="line-18"></a>
<a name="line-19"></a><span class='hs-comment'>{- |
<a name="line-20"></a> Module : System.IO.HVIO
<a name="line-21"></a> Copyright : Copyright (C) 2004-2006 John Goerzen
<a name="line-22"></a> License : GNU GPL, version 2 or above
<a name="line-23"></a>
<a name="line-24"></a> Maintainer : John Goerzen <jgoerzen@complete.org>
<a name="line-25"></a> Stability : provisional
<a name="line-26"></a> Portability: portable
<a name="line-27"></a>
<a name="line-28"></a>Haskell Virtual I\/O -- a system to increase the flexibility of input and
<a name="line-29"></a>output in Haskell
<a name="line-30"></a>
<a name="line-31"></a>Copyright (c) 2004-2005 John Goerzen, jgoerzen\@complete.org
<a name="line-32"></a>
<a name="line-33"></a>HVIO provides the following general features:
<a name="line-34"></a>
<a name="line-35"></a> * The ability to use a single set of functions on various different
<a name="line-36"></a> types of objects, including standard Handles, in-memory buffers,
<a name="line-37"></a> compressed files, network data streams, etc.
<a name="line-38"></a>
<a name="line-39"></a> * The ability to transparently add filters to the I\/O process.
<a name="line-40"></a> These filters could include things such as character set conversions,
<a name="line-41"></a> compression or decompression of a data stream, and more.
<a name="line-42"></a>
<a name="line-43"></a> * The ability to define new objects that have the properties
<a name="line-44"></a> of I\/O objects and can be used interchangably with them.
<a name="line-45"></a>
<a name="line-46"></a> * Specification compatibility with, and complete support for,
<a name="line-47"></a> existing I\/O on Handles.
<a name="line-48"></a>
<a name="line-49"></a> * Provide easier unit testing capabilities for I\/O actions
<a name="line-50"></a>
<a name="line-51"></a>HVIO defines several basic type classes that you can use. You will mostly
<a name="line-52"></a>be interested in 'HVIO'.
<a name="line-53"></a>
<a name="line-54"></a>It's trivial to adapt old code to work with HVIO. For instance, consider
<a name="line-55"></a>this example of old and new code:
<a name="line-56"></a>
<a name="line-57"></a>>printMsg :: Handle -> String -> IO ()
<a name="line-58"></a>>printMsg h msg = hPutStr h ("msg: " ++ msg)
<a name="line-59"></a>
<a name="line-60"></a>And now, the new way:
<a name="line-61"></a>
<a name="line-62"></a>>printMsg :: HVIO h => h -> String -> IO ()
<a name="line-63"></a>>printMsg h msg = vPutStr h ("msg: " ++ msg)
<a name="line-64"></a>
<a name="line-65"></a>There are several points to note about this conversion:
<a name="line-66"></a>
<a name="line-67"></a> * The new method can still accept a Handle in exactly the same way as
<a name="line-68"></a> the old method. Changing your functions to use HVIO will require no
<a name="line-69"></a> changes from functions that call them with Handles.
<a name="line-70"></a>
<a name="line-71"></a> * Most \"h\" functions have equivolent \"v\" functions that operate
<a name="line-72"></a> on HVIO classes instead of the more specific Handle. The \"v\" functions
<a name="line-73"></a> behave identically to the \"h\" functions whenever possible.
<a name="line-74"></a>
<a name="line-75"></a> * There is no equivolent of \"openFile\" in any HVIO class. You must
<a name="line-76"></a> create your Handle (or other HVIO object) using normal means.
<a name="line-77"></a> This is because the creation is so different that it cannot be standardized.
<a name="line-78"></a>
<a name="line-79"></a>In addition to Handle, there are several pre-defined classes for your use.
<a name="line-80"></a>'StreamReader' is a particularly interesting one. At creation time, you pass
<a name="line-81"></a>it a String. Its contents are read lazily whenever a read call is made. It
<a name="line-82"></a>can be used, therefore, to implement filters (simply initialize it with the
<a name="line-83"></a>result from, say, a map over hGetContents from another HVIO object), codecs,
<a name="line-84"></a>and simple I\/O testing. Because it is lazy, it need not hold the entire
<a name="line-85"></a>string in memory. You can create a 'StreamReader' with a call to
<a name="line-86"></a>'newStreamReader'.
<a name="line-87"></a>
<a name="line-88"></a>'MemoryBuffer' is a similar class, but with a different purpose. It provides
<a name="line-89"></a>a full interface like Handle (it implements 'HVIOReader', 'HVIOWriter',
<a name="line-90"></a>and 'HVIOSeeker'). However, it maintains an in-memory buffer with the
<a name="line-91"></a>contents of the file, rather than an actual on-disk file. You can access
<a name="line-92"></a>the entire contents of this buffer at any time. This can be quite useful
<a name="line-93"></a>for testing I\/O code, or for cases where existing APIs use I\/O, but you
<a name="line-94"></a>prefer a String representation. You can create a 'MemoryBuffer' with a call
<a name="line-95"></a>to 'newMemoryBuffer'.
<a name="line-96"></a>
<a name="line-97"></a>Finally, there are pipes. These pipes are analogous to the Unix
<a name="line-98"></a>pipes that are available from System.Posix, but don't require Unix and work
<a name="line-99"></a>only in Haskell. When you create a pipe, you actually get two HVIO objects:
<a name="line-100"></a>a 'PipeReader' and a 'PipeWriter'. You must use the 'PipeWriter' in one
<a name="line-101"></a>thread and the 'PipeReader' in another thread. Data that's written to the
<a name="line-102"></a>'PipeWriter' will then be available for reading with the 'PipeReader'. The
<a name="line-103"></a>pipes are implemented completely with existing Haskell threading primitives,
<a name="line-104"></a>and require no special operating system support. Unlike Unix pipes, these
<a name="line-105"></a>pipes cannot be used across a fork(). Also unlike Unix pipes, these pipes
<a name="line-106"></a>are portable and interact well with Haskell threads. A new pipe can be created
<a name="line-107"></a>with a call to 'newHVIOPipe'.
<a name="line-108"></a>
<a name="line-109"></a>Together with "System.IO.HVFS", this module is part of a complete
<a name="line-110"></a>virtual filesystem solution.
<a name="line-111"></a>-}</span>
<a name="line-112"></a>
<a name="line-113"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-conid'>HVIO</span><span class='hs-layout'>(</span><span class='hs-comment'>-- * Implementation Classes</span>
<a name="line-114"></a> <span class='hs-conid'>HVIO</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span>
<a name="line-115"></a> <span class='hs-comment'>-- * Standard HVIO Implementations</span>
<a name="line-116"></a>
<a name="line-117"></a> <span class='hs-comment'>-- ** Handle</span>
<a name="line-118"></a> <span class='hs-comment'>-- | Handle is a member of 'HVIO'.</span>
<a name="line-119"></a>
<a name="line-120"></a> <span class='hs-comment'>-- ** Stream Reader</span>
<a name="line-121"></a> <span class='hs-conid'>StreamReader</span><span class='hs-layout'>,</span> <span class='hs-varid'>newStreamReader</span><span class='hs-layout'>,</span>
<a name="line-122"></a>
<a name="line-123"></a> <span class='hs-comment'>-- ** Memory Buffer</span>
<a name="line-124"></a> <span class='hs-conid'>MemoryBuffer</span><span class='hs-layout'>,</span> <span class='hs-varid'>newMemoryBuffer</span><span class='hs-layout'>,</span>
<a name="line-125"></a> <span class='hs-varid'>mbDefaultCloseFunc</span><span class='hs-layout'>,</span> <span class='hs-varid'>getMemoryBuffer</span><span class='hs-layout'>,</span>
<a name="line-126"></a>
<a name="line-127"></a> <span class='hs-comment'>-- ** Haskell Pipe</span>
<a name="line-128"></a> <span class='hs-conid'>PipeReader</span><span class='hs-layout'>,</span> <span class='hs-conid'>PipeWriter</span><span class='hs-layout'>,</span> <span class='hs-varid'>newHVIOPipe</span>
<a name="line-129"></a> <span class='hs-layout'>)</span>
<a name="line-130"></a><span class='hs-keyword'>where</span>
<a name="line-131"></a>
<a name="line-132"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>IO</span>
<a name="line-133"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>System</span><span class='hs-varop'>.</span><span class='hs-conid'>IO</span><span class='hs-varop'>.</span><span class='hs-conid'>Error</span>
<a name="line-134"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Control</span><span class='hs-varop'>.</span><span class='hs-conid'>Concurrent</span><span class='hs-varop'>.</span><span class='hs-conid'>MVar</span>
<a name="line-135"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>IORef</span>
<a name="line-136"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>Ptr</span>
<a name="line-137"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>C</span>
<a name="line-138"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Foreign</span><span class='hs-varop'>.</span><span class='hs-conid'>Storable</span>
<a name="line-139"></a>
<a name="line-140"></a><a name="HVIO"></a><span class='hs-comment'>{- | This is the generic I\/O support class. All objects that are to be used
<a name="line-141"></a>in the HVIO system must provide an instance of 'HVIO'.
<a name="line-142"></a>
<a name="line-143"></a>Functions in this class provide an interface with the same specification as
<a name="line-144"></a>the similar functions in System.IO. Please refer to that documentation
<a name="line-145"></a>for a more complete specification than is provided here.
<a name="line-146"></a>
<a name="line-147"></a>Instances of 'HVIO' must provide 'vClose', 'vIsEOF', and either
<a name="line-148"></a>'vIsOpen' or 'vIsClosed'.
<a name="line-149"></a>
<a name="line-150"></a>Implementators of readable objects must provide at least 'vGetChar'
<a name="line-151"></a>and 'vIsReadable'.
<a name="line-152"></a>An implementation of 'vGetContents' is also highly suggested, since
<a name="line-153"></a>the default cannot implement proper partial closing semantics.
<a name="line-154"></a>
<a name="line-155"></a>Implementators of writable objects must provide at least 'vPutChar' and
<a name="line-156"></a>'vIsWritable'.
<a name="line-157"></a>
<a name="line-158"></a>Implementators of seekable objects must provide at least
<a name="line-159"></a>'vIsSeekable', 'vTell', and 'vSeek'.
<a name="line-160"></a>-}</span>
<a name="line-161"></a><a name="HVIO"></a><span class='hs-keyword'>class</span> <span class='hs-layout'>(</span><span class='hs-conid'>Show</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>HVIO</span> <span class='hs-varid'>a</span> <span class='hs-keyword'>where</span>
<a name="line-162"></a> <span class='hs-comment'>-- | Close a file</span>
<a name="line-163"></a> <span class='hs-varid'>vClose</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-164"></a> <span class='hs-comment'>-- | Test if a file is open</span>
<a name="line-165"></a> <span class='hs-varid'>vIsOpen</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>Bool</span>
<a name="line-166"></a> <span class='hs-comment'>-- | Test if a file is closed</span>
<a name="line-167"></a> <span class='hs-varid'>vIsClosed</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>Bool</span>
<a name="line-168"></a> <span class='hs-comment'>-- | Raise an error if the file is not open.</span>
<a name="line-169"></a> <span class='hs-comment'>-- This is a new HVIO function and is implemented in terms of</span>
<a name="line-170"></a> <span class='hs-comment'>-- 'vIsOpen'.</span>
<a name="line-171"></a> <span class='hs-varid'>vTestOpen</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-172"></a> <span class='hs-comment'>-- | Whether or not we're at EOF. This may raise on exception</span>
<a name="line-173"></a> <span class='hs-comment'>-- on some items, most notably write-only Handles such as stdout.</span>
<a name="line-174"></a> <span class='hs-comment'>-- In general, this is most reliable on items opened for reading.</span>
<a name="line-175"></a> <span class='hs-comment'>-- vIsEOF implementations must implicitly call vTestOpen.</span>
<a name="line-176"></a> <span class='hs-varid'>vIsEOF</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>Bool</span>
<a name="line-177"></a> <span class='hs-comment'>-- | Detailed show output.</span>
<a name="line-178"></a> <span class='hs-varid'>vShow</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>String</span>
<a name="line-179"></a> <span class='hs-comment'>-- | Make an IOError.</span>
<a name="line-180"></a> <span class='hs-varid'>vMkIOError</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IOErrorType</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-conid'>FilePath</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IOError</span>
<a name="line-181"></a> <span class='hs-comment'>-- | Throw an IOError.</span>
<a name="line-182"></a> <span class='hs-varid'>vThrow</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IOErrorType</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-varid'>b</span>
<a name="line-183"></a> <span class='hs-comment'>-- | Get the filename\/object\/whatever that this corresponds to.</span>
<a name="line-184"></a> <span class='hs-comment'>-- May be Nothing.</span>
<a name="line-185"></a> <span class='hs-varid'>vGetFP</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-layout'>(</span><span class='hs-conid'>Maybe</span> <span class='hs-conid'>FilePath</span><span class='hs-layout'>)</span>
<a name="line-186"></a> <span class='hs-comment'>-- | Throw an isEOFError if we're at EOF; returns nothing otherwise.</span>
<a name="line-187"></a> <span class='hs-comment'>-- If an implementation overrides the default, make sure that it</span>
<a name="line-188"></a> <span class='hs-comment'>-- calls vTestOpen at some point. The default implementation is</span>
<a name="line-189"></a> <span class='hs-comment'>-- a wrapper around a call to 'vIsEOF'.</span>
<a name="line-190"></a> <span class='hs-varid'>vTestEOF</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-191"></a>
<a name="line-192"></a> <span class='hs-comment'>-- | Read one character</span>
<a name="line-193"></a> <span class='hs-varid'>vGetChar</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>Char</span>
<a name="line-194"></a> <span class='hs-comment'>-- | Read one line</span>
<a name="line-195"></a> <span class='hs-varid'>vGetLine</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>String</span>
<a name="line-196"></a> <span class='hs-comment'>{- | Get the remaining contents. Please note that as a user of this
<a name="line-197"></a> function, the same partial-closing semantics as are used in the
<a name="line-198"></a> standard 'hGetContents' are /encouraged/ from implementators,
<a name="line-199"></a> but are not /required/. That means that, for instance,
<a name="line-200"></a> a 'vGetChar' after a 'vGetContents' may return some undefined
<a name="line-201"></a> result instead of the error you would normally get. You should
<a name="line-202"></a> use caution to make sure your code doesn't fall into that trap,
<a name="line-203"></a> or make sure to test your code with Handle or one of the
<a name="line-204"></a> default instances defined in this module. Also, some implementations
<a name="line-205"></a> may essentially provide a complete close after a call to 'vGetContents'.
<a name="line-206"></a> The bottom line: after a call to 'vGetContents', you should do nothing
<a name="line-207"></a> else with the object save closing it with 'vClose'.
<a name="line-208"></a>
<a name="line-209"></a> For implementators, you are highly encouraged to provide a correct
<a name="line-210"></a> implementation. -}</span>
<a name="line-211"></a> <span class='hs-varid'>vGetContents</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>String</span>
<a name="line-212"></a> <span class='hs-comment'>-- | Indicate whether at least one item is ready for reading.</span>
<a name="line-213"></a> <span class='hs-comment'>-- This will always be True for a great many implementations.</span>
<a name="line-214"></a> <span class='hs-varid'>vReady</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>Bool</span>
<a name="line-215"></a> <span class='hs-comment'>-- | Indicate whether a particular item is available for reading.</span>
<a name="line-216"></a> <span class='hs-varid'>vIsReadable</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>Bool</span>
<a name="line-217"></a>
<a name="line-218"></a> <span class='hs-comment'>-- | Write one character</span>
<a name="line-219"></a> <span class='hs-varid'>vPutChar</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Char</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-220"></a> <span class='hs-comment'>-- | Write a string</span>
<a name="line-221"></a> <span class='hs-varid'>vPutStr</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-222"></a> <span class='hs-comment'>-- | Write a string with newline character after it</span>
<a name="line-223"></a> <span class='hs-varid'>vPutStrLn</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-224"></a> <span class='hs-comment'>-- | Write a string representation of the argument, plus a newline.</span>
<a name="line-225"></a> <span class='hs-varid'>vPrint</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Show</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>=></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-226"></a> <span class='hs-comment'>-- | Flush any output buffers.</span>
<a name="line-227"></a> <span class='hs-comment'>-- Note: implementations should assure that a vFlush is automatically</span>
<a name="line-228"></a> <span class='hs-comment'>-- performed</span>
<a name="line-229"></a> <span class='hs-comment'>-- on file close, if necessary to ensure all data sent is written.</span>
<a name="line-230"></a> <span class='hs-varid'>vFlush</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-231"></a> <span class='hs-comment'>-- | Indicate whether or not this particular object supports writing.</span>
<a name="line-232"></a> <span class='hs-varid'>vIsWritable</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>Bool</span>
<a name="line-233"></a>
<a name="line-234"></a> <span class='hs-comment'>-- | Seek to a specific location.</span>
<a name="line-235"></a> <span class='hs-varid'>vSeek</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>SeekMode</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Integer</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-236"></a>
<a name="line-237"></a> <span class='hs-comment'>-- | Get the current position.</span>
<a name="line-238"></a> <span class='hs-varid'>vTell</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>Integer</span>
<a name="line-239"></a>
<a name="line-240"></a> <span class='hs-comment'>-- | Convenience function to reset the file pointer to the beginning</span>
<a name="line-241"></a> <span class='hs-comment'>-- of the file. A call to @vRewind h@ is the</span>
<a name="line-242"></a> <span class='hs-comment'>-- same as @'vSeek' h AbsoluteSeek 0@.</span>
<a name="line-243"></a> <span class='hs-varid'>vRewind</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-244"></a>
<a name="line-245"></a> <span class='hs-comment'>-- | Indicate whether this instance supports seeking.</span>
<a name="line-246"></a> <span class='hs-varid'>vIsSeekable</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>Bool</span>
<a name="line-247"></a>
<a name="line-248"></a> <span class='hs-comment'>-- | Set buffering; the default action is a no-op.</span>
<a name="line-249"></a> <span class='hs-varid'>vSetBuffering</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>BufferMode</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-250"></a>
<a name="line-251"></a> <span class='hs-comment'>-- | Get buffering; the default action always returns NoBuffering.</span>
<a name="line-252"></a> <span class='hs-varid'>vGetBuffering</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>BufferMode</span>
<a name="line-253"></a>
<a name="line-254"></a> <span class='hs-comment'>-- | Binary output: write the specified number of octets from the specified</span>
<a name="line-255"></a> <span class='hs-comment'>-- buffer location.</span>
<a name="line-256"></a> <span class='hs-varid'>vPutBuf</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Ptr</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-257"></a>
<a name="line-258"></a> <span class='hs-comment'>-- | Binary input: read the specified number of octets from the</span>
<a name="line-259"></a> <span class='hs-comment'>-- specified buffer location, continuing to read</span>
<a name="line-260"></a> <span class='hs-comment'>-- until it either consumes that much data or EOF is encountered.</span>
<a name="line-261"></a> <span class='hs-comment'>-- Returns the number of octets actually read. EOF errors are never</span>
<a name="line-262"></a> <span class='hs-comment'>-- raised; fewer bytes than requested are returned on EOF.</span>
<a name="line-263"></a> <span class='hs-varid'>vGetBuf</span> <span class='hs-keyglyph'>::</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Ptr</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>Int</span>
<a name="line-264"></a>
<a name="line-265"></a> <span class='hs-varid'>vSetBuffering</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-266"></a> <span class='hs-varid'>vGetBuffering</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>NoBuffering</span>
<a name="line-267"></a>
<a name="line-268"></a> <span class='hs-varid'>vShow</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>show</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span>
<a name="line-269"></a>
<a name="line-270"></a> <span class='hs-varid'>vMkIOError</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>et</span> <span class='hs-varid'>desc</span> <span class='hs-varid'>mfp</span> <span class='hs-keyglyph'>=</span>
<a name="line-271"></a> <span class='hs-varid'>mkIOError</span> <span class='hs-varid'>et</span> <span class='hs-varid'>desc</span> <span class='hs-conid'>Nothing</span> <span class='hs-varid'>mfp</span>
<a name="line-272"></a>
<a name="line-273"></a> <span class='hs-varid'>vGetFP</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>Nothing</span>
<a name="line-274"></a>
<a name="line-275"></a> <span class='hs-varid'>vThrow</span> <span class='hs-varid'>h</span> <span class='hs-varid'>et</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-276"></a> <span class='hs-varid'>fp</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vGetFP</span> <span class='hs-varid'>h</span>
<a name="line-277"></a> <span class='hs-varid'>ioError</span> <span class='hs-layout'>(</span><span class='hs-varid'>vMkIOError</span> <span class='hs-varid'>h</span> <span class='hs-varid'>et</span> <span class='hs-str'>""</span> <span class='hs-varid'>fp</span><span class='hs-layout'>)</span>
<a name="line-278"></a>
<a name="line-279"></a> <span class='hs-varid'>vTestEOF</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>e</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vIsEOF</span> <span class='hs-varid'>h</span>
<a name="line-280"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>e</span> <span class='hs-keyword'>then</span> <span class='hs-varid'>vThrow</span> <span class='hs-varid'>h</span> <span class='hs-varid'>eofErrorType</span>
<a name="line-281"></a> <span class='hs-keyword'>else</span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-282"></a>
<a name="line-283"></a> <span class='hs-varid'>vIsOpen</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vIsClosed</span> <span class='hs-varid'>h</span> <span class='hs-varop'>>>=</span> <span class='hs-varid'>return</span> <span class='hs-varop'>.</span> <span class='hs-varid'>not</span>
<a name="line-284"></a> <span class='hs-varid'>vIsClosed</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vIsOpen</span> <span class='hs-varid'>h</span> <span class='hs-varop'>>>=</span> <span class='hs-varid'>return</span> <span class='hs-varop'>.</span> <span class='hs-varid'>not</span>
<a name="line-285"></a> <span class='hs-varid'>vTestOpen</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>e</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vIsClosed</span> <span class='hs-varid'>h</span>
<a name="line-286"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>e</span> <span class='hs-keyword'>then</span> <span class='hs-varid'>vThrow</span> <span class='hs-varid'>h</span> <span class='hs-varid'>illegalOperationErrorType</span>
<a name="line-287"></a> <span class='hs-keyword'>else</span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-288"></a>
<a name="line-289"></a>
<a name="line-290"></a> <span class='hs-varid'>vIsReadable</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>False</span>
<a name="line-291"></a>
<a name="line-292"></a> <span class='hs-varid'>vGetLine</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span>
<a name="line-293"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>loop</span> <span class='hs-varid'>accum</span> <span class='hs-keyglyph'>=</span>
<a name="line-294"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>func</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vGetChar</span> <span class='hs-varid'>h</span>
<a name="line-295"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>c</span> <span class='hs-keyword'>of</span>
<a name="line-296"></a> <span class='hs-chr'>'\n'</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-varid'>accum</span>
<a name="line-297"></a> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>accum</span> <span class='hs-varop'>`seq`</span> <span class='hs-varid'>loop</span> <span class='hs-layout'>(</span><span class='hs-varid'>accum</span> <span class='hs-varop'>++</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>x</span><span class='hs-keyglyph'>]</span><span class='hs-layout'>)</span>
<a name="line-298"></a> <span class='hs-varid'>handler</span> <span class='hs-varid'>e</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>if</span> <span class='hs-varid'>isEOFError</span> <span class='hs-varid'>e</span> <span class='hs-keyword'>then</span> <span class='hs-varid'>return</span> <span class='hs-varid'>accum</span>
<a name="line-299"></a> <span class='hs-keyword'>else</span> <span class='hs-varid'>ioError</span> <span class='hs-varid'>e</span>
<a name="line-300"></a> <span class='hs-keyword'>in</span> <span class='hs-varid'>catch</span> <span class='hs-varid'>func</span> <span class='hs-varid'>handler</span>
<a name="line-301"></a> <span class='hs-keyword'>in</span>
<a name="line-302"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>firstchar</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vGetChar</span> <span class='hs-varid'>h</span>
<a name="line-303"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>firstchar</span> <span class='hs-keyword'>of</span>
<a name="line-304"></a> <span class='hs-chr'>'\n'</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-conid'>[]</span>
<a name="line-305"></a> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>loop</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>x</span><span class='hs-keyglyph'>]</span>
<a name="line-306"></a>
<a name="line-307"></a> <span class='hs-varid'>vGetContents</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span>
<a name="line-308"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>loop</span> <span class='hs-keyglyph'>=</span>
<a name="line-309"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>func</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vGetChar</span> <span class='hs-varid'>h</span>
<a name="line-310"></a> <span class='hs-varid'>next</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>loop</span>
<a name="line-311"></a> <span class='hs-varid'>c</span> <span class='hs-varop'>`seq`</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>c</span> <span class='hs-conop'>:</span> <span class='hs-varid'>next</span><span class='hs-layout'>)</span>
<a name="line-312"></a> <span class='hs-varid'>handler</span> <span class='hs-varid'>e</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>if</span> <span class='hs-varid'>isEOFError</span> <span class='hs-varid'>e</span> <span class='hs-keyword'>then</span> <span class='hs-varid'>return</span> <span class='hs-conid'>[]</span>
<a name="line-313"></a> <span class='hs-keyword'>else</span> <span class='hs-varid'>ioError</span> <span class='hs-varid'>e</span>
<a name="line-314"></a> <span class='hs-keyword'>in</span> <span class='hs-varid'>catch</span> <span class='hs-varid'>func</span> <span class='hs-varid'>handler</span>
<a name="line-315"></a> <span class='hs-keyword'>in</span>
<a name="line-316"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>loop</span>
<a name="line-317"></a>
<a name="line-318"></a> <span class='hs-varid'>vReady</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>vTestEOF</span> <span class='hs-varid'>h</span>
<a name="line-319"></a> <span class='hs-varid'>return</span> <span class='hs-conid'>True</span>
<a name="line-320"></a>
<a name="line-321"></a>
<a name="line-322"></a> <span class='hs-varid'>vIsWritable</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>False</span>
<a name="line-323"></a>
<a name="line-324"></a> <span class='hs-varid'>vPutStr</span> <span class='hs-keyword'>_</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-325"></a> <span class='hs-varid'>vPutStr</span> <span class='hs-varid'>h</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-conop'>:</span><span class='hs-varid'>xs</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>vPutChar</span> <span class='hs-varid'>h</span> <span class='hs-varid'>x</span>
<a name="line-326"></a> <span class='hs-varid'>vPutStr</span> <span class='hs-varid'>h</span> <span class='hs-varid'>xs</span>
<a name="line-327"></a>
<a name="line-328"></a> <span class='hs-varid'>vPutStrLn</span> <span class='hs-varid'>h</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vPutStr</span> <span class='hs-varid'>h</span> <span class='hs-layout'>(</span><span class='hs-varid'>s</span> <span class='hs-varop'>++</span> <span class='hs-str'>"\n"</span><span class='hs-layout'>)</span>
<a name="line-329"></a>
<a name="line-330"></a> <span class='hs-varid'>vPrint</span> <span class='hs-varid'>h</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vPutStrLn</span> <span class='hs-varid'>h</span> <span class='hs-layout'>(</span><span class='hs-varid'>show</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-331"></a>
<a name="line-332"></a> <span class='hs-varid'>vFlush</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vTestOpen</span>
<a name="line-333"></a>
<a name="line-334"></a>
<a name="line-335"></a> <span class='hs-varid'>vIsSeekable</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>False</span>
<a name="line-336"></a>
<a name="line-337"></a> <span class='hs-varid'>vRewind</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vSeek</span> <span class='hs-varid'>h</span> <span class='hs-conid'>AbsoluteSeek</span> <span class='hs-num'>0</span>
<a name="line-338"></a>
<a name="line-339"></a> <span class='hs-varid'>vPutChar</span> <span class='hs-varid'>h</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vThrow</span> <span class='hs-varid'>h</span> <span class='hs-varid'>illegalOperationErrorType</span>
<a name="line-340"></a> <span class='hs-varid'>vSeek</span> <span class='hs-varid'>h</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vThrow</span> <span class='hs-varid'>h</span> <span class='hs-varid'>illegalOperationErrorType</span>
<a name="line-341"></a> <span class='hs-varid'>vTell</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vThrow</span> <span class='hs-varid'>h</span> <span class='hs-varid'>illegalOperationErrorType</span>
<a name="line-342"></a> <span class='hs-varid'>vGetChar</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vThrow</span> <span class='hs-varid'>h</span> <span class='hs-varid'>illegalOperationErrorType</span>
<a name="line-343"></a>
<a name="line-344"></a>
<a name="line-345"></a> <span class='hs-varid'>vPutBuf</span> <span class='hs-varid'>h</span> <span class='hs-varid'>buf</span> <span class='hs-varid'>len</span> <span class='hs-keyglyph'>=</span>
<a name="line-346"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>str</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>peekCStringLen</span> <span class='hs-layout'>(</span><span class='hs-varid'>castPtr</span> <span class='hs-varid'>buf</span><span class='hs-layout'>,</span> <span class='hs-varid'>len</span><span class='hs-layout'>)</span>
<a name="line-347"></a> <span class='hs-varid'>vPutStr</span> <span class='hs-varid'>h</span> <span class='hs-varid'>str</span>
<a name="line-348"></a>
<a name="line-349"></a> <span class='hs-varid'>vGetBuf</span> <span class='hs-varid'>h</span> <span class='hs-varid'>b</span> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span>
<a name="line-350"></a> <span class='hs-varid'>worker</span> <span class='hs-varid'>b</span> <span class='hs-varid'>l</span> <span class='hs-num'>0</span>
<a name="line-351"></a> <span class='hs-keyword'>where</span> <span class='hs-varid'>worker</span> <span class='hs-keyword'>_</span> <span class='hs-num'>0</span> <span class='hs-varid'>accum</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-varid'>accum</span>
<a name="line-352"></a> <span class='hs-varid'>worker</span> <span class='hs-varid'>buf</span> <span class='hs-varid'>len</span> <span class='hs-varid'>accum</span> <span class='hs-keyglyph'>=</span>
<a name="line-353"></a> <span class='hs-keyword'>do</span> <span class='hs-varid'>iseof</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vIsEOF</span> <span class='hs-varid'>h</span>
<a name="line-354"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>iseof</span>
<a name="line-355"></a> <span class='hs-keyword'>then</span> <span class='hs-varid'>return</span> <span class='hs-varid'>accum</span>
<a name="line-356"></a> <span class='hs-keyword'>else</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vGetChar</span> <span class='hs-varid'>h</span>
<a name="line-357"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>cc</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>castCharToCChar</span> <span class='hs-varid'>c</span>
<a name="line-358"></a> <span class='hs-varid'>poke</span> <span class='hs-layout'>(</span><span class='hs-varid'>castPtr</span> <span class='hs-varid'>buf</span><span class='hs-layout'>)</span> <span class='hs-varid'>cc</span>
<a name="line-359"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>newptr</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>plusPtr</span> <span class='hs-varid'>buf</span> <span class='hs-num'>1</span>
<a name="line-360"></a> <span class='hs-varid'>worker</span> <span class='hs-varid'>newptr</span> <span class='hs-layout'>(</span><span class='hs-varid'>len</span> <span class='hs-comment'>-</span> <span class='hs-num'>1</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>accum</span> <span class='hs-varop'>+</span> <span class='hs-num'>1</span><span class='hs-layout'>)</span>
<a name="line-361"></a>
<a name="line-362"></a><span class='hs-comment'>----------------------------------------------------------------------</span>
<a name="line-363"></a><span class='hs-comment'>-- Handle instances</span>
<a name="line-364"></a><span class='hs-comment'>----------------------------------------------------------------------</span>
<a name="line-365"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>HVIO</span> <span class='hs-conid'>Handle</span> <span class='hs-keyword'>where</span>
<a name="line-366"></a> <span class='hs-varid'>vClose</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hClose</span>
<a name="line-367"></a> <span class='hs-varid'>vIsEOF</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hIsEOF</span>
<a name="line-368"></a><span class='hs-cpp'>#ifdef __GLASGOW_HASKELL__</span>
<a name="line-369"></a> <span class='hs-varid'>vShow</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hShow</span>
<a name="line-370"></a><span class='hs-cpp'>#endif</span>
<a name="line-371"></a> <span class='hs-varid'>vMkIOError</span> <span class='hs-varid'>h</span> <span class='hs-varid'>et</span> <span class='hs-varid'>desc</span> <span class='hs-varid'>mfp</span> <span class='hs-keyglyph'>=</span>
<a name="line-372"></a> <span class='hs-varid'>mkIOError</span> <span class='hs-varid'>et</span> <span class='hs-varid'>desc</span> <span class='hs-layout'>(</span><span class='hs-conid'>Just</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span> <span class='hs-varid'>mfp</span>
<a name="line-373"></a> <span class='hs-varid'>vGetChar</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hGetChar</span>
<a name="line-374"></a> <span class='hs-varid'>vGetLine</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hGetLine</span>
<a name="line-375"></a> <span class='hs-varid'>vGetContents</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hGetContents</span>
<a name="line-376"></a> <span class='hs-varid'>vReady</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hReady</span>
<a name="line-377"></a> <span class='hs-varid'>vIsReadable</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hIsReadable</span>
<a name="line-378"></a> <span class='hs-varid'>vPutChar</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hPutChar</span>
<a name="line-379"></a> <span class='hs-varid'>vPutStr</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hPutStr</span>
<a name="line-380"></a> <span class='hs-varid'>vPutStrLn</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hPutStrLn</span>
<a name="line-381"></a> <span class='hs-varid'>vPrint</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hPrint</span>
<a name="line-382"></a> <span class='hs-varid'>vFlush</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hFlush</span>
<a name="line-383"></a> <span class='hs-varid'>vIsWritable</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hIsWritable</span>
<a name="line-384"></a> <span class='hs-varid'>vSeek</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hSeek</span>
<a name="line-385"></a> <span class='hs-varid'>vTell</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hTell</span>
<a name="line-386"></a> <span class='hs-varid'>vIsSeekable</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hIsSeekable</span>
<a name="line-387"></a> <span class='hs-varid'>vSetBuffering</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hSetBuffering</span>
<a name="line-388"></a> <span class='hs-varid'>vGetBuffering</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hGetBuffering</span>
<a name="line-389"></a> <span class='hs-varid'>vGetBuf</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hGetBuf</span>
<a name="line-390"></a> <span class='hs-varid'>vPutBuf</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hPutBuf</span>
<a name="line-391"></a> <span class='hs-varid'>vIsOpen</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hIsOpen</span>
<a name="line-392"></a> <span class='hs-varid'>vIsClosed</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>hIsClosed</span>
<a name="line-393"></a>
<a name="line-394"></a><a name="VIOCloseSupport"></a><span class='hs-comment'>----------------------------------------------------------------------</span>
<a name="line-395"></a><a name="VIOCloseSupport"></a><span class='hs-comment'>-- VIO Support</span>
<a name="line-396"></a><a name="VIOCloseSupport"></a><span class='hs-comment'>----------------------------------------------------------------------</span>
<a name="line-397"></a><a name="VIOCloseSupport"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>VIOCloseSupport</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>IORef</span> <span class='hs-layout'>(</span><span class='hs-conid'>Bool</span><span class='hs-layout'>,</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-398"></a>
<a name="line-399"></a><a name="vioc_isopen"></a><span class='hs-definition'>vioc_isopen</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>VIOCloseSupport</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>Bool</span>
<a name="line-400"></a><span class='hs-definition'>vioc_isopen</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>readIORef</span> <span class='hs-varid'>x</span> <span class='hs-varop'>>>=</span> <span class='hs-varid'>return</span> <span class='hs-varop'>.</span> <span class='hs-varid'>fst</span>
<a name="line-401"></a>
<a name="line-402"></a><a name="vioc_get"></a><span class='hs-definition'>vioc_get</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>VIOCloseSupport</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-varid'>a</span>
<a name="line-403"></a><span class='hs-definition'>vioc_get</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>readIORef</span> <span class='hs-varid'>x</span> <span class='hs-varop'>>>=</span> <span class='hs-varid'>return</span> <span class='hs-varop'>.</span> <span class='hs-varid'>snd</span>
<a name="line-404"></a>
<a name="line-405"></a><a name="vioc_close"></a><span class='hs-definition'>vioc_close</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>VIOCloseSupport</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-406"></a><span class='hs-definition'>vioc_close</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>modifyIORef</span> <span class='hs-varid'>x</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span> <span class='hs-layout'>(</span><span class='hs-keyword'>_</span><span class='hs-layout'>,</span> <span class='hs-varid'>dat</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>False</span><span class='hs-layout'>,</span> <span class='hs-varid'>dat</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-407"></a>
<a name="line-408"></a><a name="vioc_set"></a><span class='hs-definition'>vioc_set</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>VIOCloseSupport</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-409"></a><span class='hs-definition'>vioc_set</span> <span class='hs-varid'>x</span> <span class='hs-varid'>newdat</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>modifyIORef</span> <span class='hs-varid'>x</span> <span class='hs-layout'>(</span><span class='hs-keyglyph'>\</span> <span class='hs-layout'>(</span><span class='hs-varid'>stat</span><span class='hs-layout'>,</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>stat</span><span class='hs-layout'>,</span> <span class='hs-varid'>newdat</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-410"></a>
<a name="line-411"></a><a name="StreamReader"></a><span class='hs-comment'>----------------------------------------------------------------------</span>
<a name="line-412"></a><a name="StreamReader"></a><span class='hs-comment'>-- Stream Readers</span>
<a name="line-413"></a><a name="StreamReader"></a><span class='hs-comment'>----------------------------------------------------------------------</span>
<a name="line-414"></a><a name="StreamReader"></a><span class='hs-comment'>{- | Simulate I\/O based on a string buffer.
<a name="line-415"></a>
<a name="line-416"></a>When a 'StreamReader' is created, it is initialized based on the contents of
<a name="line-417"></a>a 'String'. Its contents are read lazily whenever a request is made to read
<a name="line-418"></a>something from the 'StreamReader'. It
<a name="line-419"></a>can be used, therefore, to implement filters (simply initialize it with the
<a name="line-420"></a>result from, say, a map over hGetContents from another HVIO object), codecs,
<a name="line-421"></a>and simple I\/O testing. Because it is lazy, it need not hold the entire
<a name="line-422"></a>string in memory. You can create a 'StreamReader' with a call to
<a name="line-423"></a>'newStreamReader'.
<a name="line-424"></a> -}</span>
<a name="line-425"></a><a name="StreamReader"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>StreamReader</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>StreamReader</span> <span class='hs-layout'>(</span><span class='hs-conid'>VIOCloseSupport</span> <span class='hs-conid'>String</span><span class='hs-layout'>)</span>
<a name="line-426"></a>
<a name="line-427"></a><a name="newStreamReader"></a><span class='hs-comment'>{- | Create a new 'StreamReader' object. -}</span>
<a name="line-428"></a><span class='hs-definition'>newStreamReader</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>String</span> <span class='hs-comment'>-- ^ Initial contents of the 'StreamReader'</span>
<a name="line-429"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>StreamReader</span>
<a name="line-430"></a><span class='hs-definition'>newStreamReader</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>ref</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>newIORef</span> <span class='hs-layout'>(</span><span class='hs-conid'>True</span><span class='hs-layout'>,</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span>
<a name="line-431"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>StreamReader</span> <span class='hs-varid'>ref</span><span class='hs-layout'>)</span>
<a name="line-432"></a>
<a name="line-433"></a><a name="srv"></a><span class='hs-definition'>srv</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>StreamReader</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>VIOCloseSupport</span> <span class='hs-conid'>String</span>
<a name="line-434"></a><span class='hs-definition'>srv</span> <span class='hs-layout'>(</span><span class='hs-conid'>StreamReader</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>x</span>
<a name="line-435"></a>
<a name="line-436"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Show</span> <span class='hs-conid'>StreamReader</span> <span class='hs-keyword'>where</span>
<a name="line-437"></a> <span class='hs-varid'>show</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-str'>"<StreamReader>"</span>
<a name="line-438"></a>
<a name="line-439"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>HVIO</span> <span class='hs-conid'>StreamReader</span> <span class='hs-keyword'>where</span>
<a name="line-440"></a> <span class='hs-varid'>vClose</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vioc_close</span> <span class='hs-varop'>.</span> <span class='hs-varid'>srv</span>
<a name="line-441"></a> <span class='hs-varid'>vIsEOF</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>vTestOpen</span> <span class='hs-varid'>h</span>
<a name="line-442"></a> <span class='hs-varid'>d</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vioc_get</span> <span class='hs-layout'>(</span><span class='hs-varid'>srv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span>
<a name="line-443"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>d</span> <span class='hs-keyword'>of</span>
<a name="line-444"></a> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>True</span>
<a name="line-445"></a> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>False</span>
<a name="line-446"></a> <span class='hs-varid'>vIsOpen</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vioc_isopen</span> <span class='hs-varop'>.</span> <span class='hs-varid'>srv</span>
<a name="line-447"></a> <span class='hs-varid'>vGetChar</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>vTestEOF</span> <span class='hs-varid'>h</span>
<a name="line-448"></a> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vioc_get</span> <span class='hs-layout'>(</span><span class='hs-varid'>srv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span>
<a name="line-449"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>retval</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>head</span> <span class='hs-varid'>c</span>
<a name="line-450"></a> <span class='hs-varid'>vioc_set</span> <span class='hs-layout'>(</span><span class='hs-varid'>srv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>tail</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span>
<a name="line-451"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>retval</span>
<a name="line-452"></a>
<a name="line-453"></a> <span class='hs-varid'>vGetContents</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>vTestEOF</span> <span class='hs-varid'>h</span>
<a name="line-454"></a> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vioc_get</span> <span class='hs-layout'>(</span><span class='hs-varid'>srv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span>
<a name="line-455"></a> <span class='hs-varid'>vClose</span> <span class='hs-varid'>h</span>
<a name="line-456"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>c</span>
<a name="line-457"></a> <span class='hs-varid'>vIsReadable</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>True</span>
<a name="line-458"></a>
<a name="line-459"></a><a name="MemoryBuffer"></a><span class='hs-comment'>----------------------------------------------------------------------</span>
<a name="line-460"></a><a name="MemoryBuffer"></a><span class='hs-comment'>-- Buffers</span>
<a name="line-461"></a><a name="MemoryBuffer"></a><span class='hs-comment'>----------------------------------------------------------------------</span>
<a name="line-462"></a><a name="MemoryBuffer"></a><span class='hs-comment'>{- | A 'MemoryBuffer' simulates true I\/O, but uses an in-memory buffer instead
<a name="line-463"></a>of on-disk storage.
<a name="line-464"></a>
<a name="line-465"></a>It provides
<a name="line-466"></a>a full interface like Handle (it implements 'HVIOReader', 'HVIOWriter',
<a name="line-467"></a>and 'HVIOSeeker'). However, it maintains an in-memory buffer with the
<a name="line-468"></a>contents of the file, rather than an actual on-disk file. You can access
<a name="line-469"></a>the entire contents of this buffer at any time. This can be quite useful
<a name="line-470"></a>for testing I\/O code, or for cases where existing APIs use I\/O, but you
<a name="line-471"></a>prefer a String representation. You can create a 'MemoryBuffer' with a call
<a name="line-472"></a>to 'newMemoryBuffer'.
<a name="line-473"></a>
<a name="line-474"></a>The present 'MemoryBuffer' implementation is rather inefficient, particularly
<a name="line-475"></a>when reading towards the end of large files. It's best used for smallish
<a name="line-476"></a>data storage. This problem will be fixed eventually.
<a name="line-477"></a>-}</span>
<a name="line-478"></a><a name="MemoryBuffer"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>MemoryBuffer</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>MemoryBuffer</span> <span class='hs-layout'>(</span><span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-conid'>VIOCloseSupport</span> <span class='hs-layout'>(</span><span class='hs-conid'>Int</span><span class='hs-layout'>,</span> <span class='hs-conid'>String</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-479"></a>
<a name="line-480"></a><a name="newMemoryBuffer"></a><span class='hs-comment'>{- | Create a new 'MemoryBuffer' instance. The buffer is initialized
<a name="line-481"></a>to the value passed, and the pointer is placed at the beginning of the file.
<a name="line-482"></a>
<a name="line-483"></a>You can put things in it by using the normal 'vPutStr' calls, and reset to
<a name="line-484"></a>the beginning by using the normal 'vRewind' call.
<a name="line-485"></a>
<a name="line-486"></a>The function is called when 'vClose' is called, and is passed the contents of
<a name="line-487"></a>the buffer at close time. You can use 'mbDefaultCloseFunc' if you don't want to
<a name="line-488"></a>do anything.
<a name="line-489"></a>
<a name="line-490"></a>To create an empty buffer, pass the initial value @\"\"@. -}</span>
<a name="line-491"></a><span class='hs-definition'>newMemoryBuffer</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>String</span> <span class='hs-comment'>-- ^ Initial Contents</span>
<a name="line-492"></a> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span><span class='hs-layout'>)</span> <span class='hs-comment'>-- ^ close func</span>
<a name="line-493"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>MemoryBuffer</span>
<a name="line-494"></a><span class='hs-definition'>newMemoryBuffer</span> <span class='hs-varid'>initval</span> <span class='hs-varid'>closefunc</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>ref</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>newIORef</span> <span class='hs-layout'>(</span><span class='hs-conid'>True</span><span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-num'>0</span><span class='hs-layout'>,</span> <span class='hs-varid'>initval</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-495"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-conid'>MemoryBuffer</span> <span class='hs-varid'>closefunc</span> <span class='hs-varid'>ref</span><span class='hs-layout'>)</span>
<a name="line-496"></a>
<a name="line-497"></a><a name="mbDefaultCloseFunc"></a><span class='hs-comment'>{- | Default (no-op) memory buf close function. -}</span>
<a name="line-498"></a><span class='hs-definition'>mbDefaultCloseFunc</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>()</span>
<a name="line-499"></a><span class='hs-definition'>mbDefaultCloseFunc</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-500"></a>
<a name="line-501"></a><a name="vrv"></a><span class='hs-definition'>vrv</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MemoryBuffer</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>VIOCloseSupport</span> <span class='hs-layout'>(</span><span class='hs-conid'>Int</span><span class='hs-layout'>,</span> <span class='hs-conid'>String</span><span class='hs-layout'>)</span>
<a name="line-502"></a><span class='hs-definition'>vrv</span> <span class='hs-layout'>(</span><span class='hs-conid'>MemoryBuffer</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>x</span>
<a name="line-503"></a>
<a name="line-504"></a><a name="getMemoryBuffer"></a><span class='hs-comment'>{- | Grab the entire contents of the buffer as a string.
<a name="line-505"></a>Unlike 'vGetContents', this has no effect on the open status of the
<a name="line-506"></a>item, the EOF status, or the current position of the file pointer. -}</span>
<a name="line-507"></a><span class='hs-definition'>getMemoryBuffer</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>MemoryBuffer</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>String</span>
<a name="line-508"></a><span class='hs-definition'>getMemoryBuffer</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vioc_get</span> <span class='hs-layout'>(</span><span class='hs-varid'>vrv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span>
<a name="line-509"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>snd</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span>
<a name="line-510"></a>
<a name="line-511"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Show</span> <span class='hs-conid'>MemoryBuffer</span> <span class='hs-keyword'>where</span>
<a name="line-512"></a> <span class='hs-varid'>show</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-str'>"<MemoryBuffer>"</span>
<a name="line-513"></a>
<a name="line-514"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>HVIO</span> <span class='hs-conid'>MemoryBuffer</span> <span class='hs-keyword'>where</span>
<a name="line-515"></a> <span class='hs-varid'>vClose</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>wasopen</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vIsOpen</span> <span class='hs-varid'>x</span>
<a name="line-516"></a> <span class='hs-varid'>vioc_close</span> <span class='hs-layout'>(</span><span class='hs-varid'>vrv</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span>
<a name="line-517"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>wasopen</span>
<a name="line-518"></a> <span class='hs-keyword'>then</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>getMemoryBuffer</span> <span class='hs-varid'>x</span>
<a name="line-519"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>x</span> <span class='hs-keyword'>of</span>
<a name="line-520"></a> <span class='hs-conid'>MemoryBuffer</span> <span class='hs-varid'>cf</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>cf</span> <span class='hs-varid'>c</span>
<a name="line-521"></a> <span class='hs-keyword'>else</span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-522"></a> <span class='hs-varid'>vIsEOF</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>vTestOpen</span> <span class='hs-varid'>h</span>
<a name="line-523"></a> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vioc_get</span> <span class='hs-layout'>(</span><span class='hs-varid'>vrv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span>
<a name="line-524"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>length</span> <span class='hs-layout'>(</span><span class='hs-varid'>snd</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-varop'>==</span> <span class='hs-layout'>(</span><span class='hs-varid'>fst</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-525"></a> <span class='hs-varid'>vIsOpen</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vioc_isopen</span> <span class='hs-varop'>.</span> <span class='hs-varid'>vrv</span>
<a name="line-526"></a> <span class='hs-varid'>vGetChar</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>vTestEOF</span> <span class='hs-varid'>h</span>
<a name="line-527"></a> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vioc_get</span> <span class='hs-layout'>(</span><span class='hs-varid'>vrv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span>
<a name="line-528"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>retval</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>snd</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span> <span class='hs-varop'>!!</span> <span class='hs-layout'>(</span><span class='hs-varid'>fst</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span>
<a name="line-529"></a> <span class='hs-varid'>vioc_set</span> <span class='hs-layout'>(</span><span class='hs-varid'>vrv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>succ</span> <span class='hs-layout'>(</span><span class='hs-varid'>fst</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>snd</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span>
<a name="line-530"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>retval</span>
<a name="line-531"></a> <span class='hs-varid'>vGetContents</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>vTestEOF</span> <span class='hs-varid'>h</span>
<a name="line-532"></a> <span class='hs-varid'>v</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vioc_get</span> <span class='hs-layout'>(</span><span class='hs-varid'>vrv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span>
<a name="line-533"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>retval</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>drop</span> <span class='hs-layout'>(</span><span class='hs-varid'>fst</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>snd</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span>
<a name="line-534"></a> <span class='hs-varid'>vioc_set</span> <span class='hs-layout'>(</span><span class='hs-varid'>vrv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-comment'>-</span><span class='hs-num'>1</span><span class='hs-layout'>,</span> <span class='hs-str'>""</span><span class='hs-layout'>)</span>
<a name="line-535"></a> <span class='hs-varid'>vClose</span> <span class='hs-varid'>h</span>
<a name="line-536"></a> <span class='hs-varid'>return</span> <span class='hs-varid'>retval</span>
<a name="line-537"></a> <span class='hs-varid'>vIsReadable</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>True</span>
<a name="line-538"></a>
<a name="line-539"></a> <span class='hs-varid'>vPutStr</span> <span class='hs-varid'>h</span> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-layout'>(</span><span class='hs-varid'>pos</span><span class='hs-layout'>,</span> <span class='hs-varid'>buf</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vioc_get</span> <span class='hs-layout'>(</span><span class='hs-varid'>vrv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span>
<a name="line-540"></a> <span class='hs-keyword'>let</span> <span class='hs-layout'>(</span><span class='hs-varid'>pre</span><span class='hs-layout'>,</span> <span class='hs-varid'>post</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>splitAt</span> <span class='hs-varid'>pos</span> <span class='hs-varid'>buf</span>
<a name="line-541"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>newbuf</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>pre</span> <span class='hs-varop'>++</span> <span class='hs-varid'>s</span> <span class='hs-varop'>++</span> <span class='hs-layout'>(</span><span class='hs-varid'>drop</span> <span class='hs-layout'>(</span><span class='hs-varid'>length</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span> <span class='hs-varid'>post</span><span class='hs-layout'>)</span>
<a name="line-542"></a> <span class='hs-varid'>vioc_set</span> <span class='hs-layout'>(</span><span class='hs-varid'>vrv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>pos</span> <span class='hs-varop'>+</span> <span class='hs-layout'>(</span><span class='hs-varid'>length</span> <span class='hs-varid'>s</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>newbuf</span><span class='hs-layout'>)</span>
<a name="line-543"></a> <span class='hs-varid'>vPutChar</span> <span class='hs-varid'>h</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vPutStr</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>c</span><span class='hs-keyglyph'>]</span>
<a name="line-544"></a> <span class='hs-varid'>vIsWritable</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>True</span>
<a name="line-545"></a> <span class='hs-varid'>vTell</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>v</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vioc_get</span> <span class='hs-layout'>(</span><span class='hs-varid'>vrv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span>
<a name="line-546"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>.</span> <span class='hs-varid'>fromIntegral</span> <span class='hs-varop'>$</span> <span class='hs-layout'>(</span><span class='hs-varid'>fst</span> <span class='hs-varid'>v</span><span class='hs-layout'>)</span>
<a name="line-547"></a> <span class='hs-varid'>vSeek</span> <span class='hs-varid'>h</span> <span class='hs-varid'>seekmode</span> <span class='hs-varid'>seekposp</span> <span class='hs-keyglyph'>=</span>
<a name="line-548"></a> <span class='hs-keyword'>do</span> <span class='hs-layout'>(</span><span class='hs-varid'>pos</span><span class='hs-layout'>,</span> <span class='hs-varid'>buf</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vioc_get</span> <span class='hs-layout'>(</span><span class='hs-varid'>vrv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span>
<a name="line-549"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>seekpos</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fromInteger</span> <span class='hs-varid'>seekposp</span>
<a name="line-550"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>newpos</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>case</span> <span class='hs-varid'>seekmode</span> <span class='hs-keyword'>of</span>
<a name="line-551"></a> <span class='hs-conid'>AbsoluteSeek</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>seekpos</span>
<a name="line-552"></a> <span class='hs-conid'>RelativeSeek</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>pos</span> <span class='hs-varop'>+</span> <span class='hs-varid'>seekpos</span>
<a name="line-553"></a> <span class='hs-conid'>SeekFromEnd</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>length</span> <span class='hs-varid'>buf</span><span class='hs-layout'>)</span> <span class='hs-varop'>+</span> <span class='hs-varid'>seekpos</span>
<a name="line-554"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>buf2</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>buf</span> <span class='hs-varop'>++</span> <span class='hs-keyword'>if</span> <span class='hs-varid'>newpos</span> <span class='hs-varop'>></span> <span class='hs-layout'>(</span><span class='hs-varid'>length</span> <span class='hs-varid'>buf</span><span class='hs-layout'>)</span>
<a name="line-555"></a> <span class='hs-keyword'>then</span> <span class='hs-varid'>replicate</span> <span class='hs-layout'>(</span><span class='hs-varid'>newpos</span> <span class='hs-comment'>-</span> <span class='hs-layout'>(</span><span class='hs-varid'>length</span> <span class='hs-varid'>buf</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-chr'>'\0'</span>
<a name="line-556"></a> <span class='hs-keyword'>else</span> <span class='hs-conid'>[]</span>
<a name="line-557"></a> <span class='hs-varid'>vioc_set</span> <span class='hs-layout'>(</span><span class='hs-varid'>vrv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>newpos</span><span class='hs-layout'>,</span> <span class='hs-varid'>buf2</span><span class='hs-layout'>)</span>
<a name="line-558"></a> <span class='hs-varid'>vIsSeekable</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>True</span>
<a name="line-559"></a>
<a name="line-560"></a><a name="newHVIOPipe"></a><span class='hs-comment'>----------------------------------------------------------------------</span>
<a name="line-561"></a><span class='hs-comment'>-- Pipes</span>
<a name="line-562"></a><span class='hs-comment'>----------------------------------------------------------------------</span>
<a name="line-563"></a><span class='hs-comment'>{- | Create a Haskell pipe.
<a name="line-564"></a>
<a name="line-565"></a>These pipes are analogous to the Unix
<a name="line-566"></a>pipes that are available from System.Posix, but don't require Unix and work
<a name="line-567"></a>only in Haskell. When you create a pipe, you actually get two HVIO objects:
<a name="line-568"></a>a 'PipeReader' and a 'PipeWriter'. You must use the 'PipeWriter' in one
<a name="line-569"></a>thread and the 'PipeReader' in another thread. Data that's written to the
<a name="line-570"></a>'PipeWriter' will then be available for reading with the 'PipeReader'. The
<a name="line-571"></a>pipes are implemented completely with existing Haskell threading primitives,
<a name="line-572"></a>and require no special operating system support. Unlike Unix pipes, these
<a name="line-573"></a>pipes cannot be used across a fork(). Also unlike Unix pipes, these pipes
<a name="line-574"></a>are portable and interact well with Haskell threads. -}</span>
<a name="line-575"></a><span class='hs-definition'>newHVIOPipe</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>IO</span> <span class='hs-layout'>(</span><span class='hs-conid'>PipeReader</span><span class='hs-layout'>,</span> <span class='hs-conid'>PipeWriter</span><span class='hs-layout'>)</span>
<a name="line-576"></a><span class='hs-definition'>newHVIOPipe</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>mv</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>newEmptyMVar</span>
<a name="line-577"></a> <span class='hs-varid'>readerref</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>newIORef</span> <span class='hs-layout'>(</span><span class='hs-conid'>True</span><span class='hs-layout'>,</span> <span class='hs-varid'>mv</span><span class='hs-layout'>)</span>
<a name="line-578"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>reader</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>PipeReader</span> <span class='hs-varid'>readerref</span>
<a name="line-579"></a> <span class='hs-varid'>writerref</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>newIORef</span> <span class='hs-layout'>(</span><span class='hs-conid'>True</span><span class='hs-layout'>,</span> <span class='hs-varid'>reader</span><span class='hs-layout'>)</span>
<a name="line-580"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>reader</span><span class='hs-layout'>,</span> <span class='hs-conid'>PipeWriter</span> <span class='hs-varid'>writerref</span><span class='hs-layout'>)</span>
<a name="line-581"></a>
<a name="line-582"></a><a name="PipeBit"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>PipeBit</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>PipeBit</span> <span class='hs-conid'>Char</span>
<a name="line-583"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>PipeEOF</span>
<a name="line-584"></a> <span class='hs-keyword'>deriving</span> <span class='hs-layout'>(</span><span class='hs-conid'>Eq</span><span class='hs-layout'>,</span> <span class='hs-conid'>Show</span><span class='hs-layout'>)</span>
<a name="line-585"></a>
<a name="line-586"></a><a name="PipeReader"></a><span class='hs-comment'>{- | The reading side of a Haskell pipe. Please see 'newHVIOPipe' for more
<a name="line-587"></a>details. -}</span>
<a name="line-588"></a><a name="PipeReader"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>PipeReader</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>PipeReader</span> <span class='hs-layout'>(</span><span class='hs-conid'>VIOCloseSupport</span> <span class='hs-layout'>(</span><span class='hs-conid'>MVar</span> <span class='hs-conid'>PipeBit</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-589"></a>
<a name="line-590"></a><a name="PipeWriter"></a><span class='hs-comment'>{- | The writing side of a Haskell pipe. Please see 'newHVIOPipe' for more
<a name="line-591"></a>details. -}</span>
<a name="line-592"></a><a name="PipeWriter"></a><span class='hs-keyword'>newtype</span> <span class='hs-conid'>PipeWriter</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>PipeWriter</span> <span class='hs-layout'>(</span><span class='hs-conid'>VIOCloseSupport</span> <span class='hs-conid'>PipeReader</span><span class='hs-layout'>)</span>
<a name="line-593"></a>
<a name="line-594"></a><a name="prv"></a><span class='hs-comment'>------------------------------</span>
<a name="line-595"></a><span class='hs-comment'>-- Pipe Reader</span>
<a name="line-596"></a><span class='hs-comment'>------------------------------</span>
<a name="line-597"></a><span class='hs-definition'>prv</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>PipeReader</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>VIOCloseSupport</span> <span class='hs-layout'>(</span><span class='hs-conid'>MVar</span> <span class='hs-conid'>PipeBit</span><span class='hs-layout'>)</span>
<a name="line-598"></a><span class='hs-definition'>prv</span> <span class='hs-layout'>(</span><span class='hs-conid'>PipeReader</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>x</span>
<a name="line-599"></a>
<a name="line-600"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Show</span> <span class='hs-conid'>PipeReader</span> <span class='hs-keyword'>where</span>
<a name="line-601"></a> <span class='hs-varid'>show</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-str'>"<PipeReader>"</span>
<a name="line-602"></a>
<a name="line-603"></a><a name="pr_getc"></a><span class='hs-definition'>pr_getc</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>PipeReader</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-conid'>PipeBit</span>
<a name="line-604"></a><span class='hs-definition'>pr_getc</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>mv</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vioc_get</span> <span class='hs-layout'>(</span><span class='hs-varid'>prv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span>
<a name="line-605"></a> <span class='hs-varid'>takeMVar</span> <span class='hs-varid'>mv</span>
<a name="line-606"></a>
<a name="line-607"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>HVIO</span> <span class='hs-conid'>PipeReader</span> <span class='hs-keyword'>where</span>
<a name="line-608"></a> <span class='hs-varid'>vClose</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vioc_close</span> <span class='hs-varop'>.</span> <span class='hs-varid'>prv</span>
<a name="line-609"></a> <span class='hs-varid'>vIsOpen</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vioc_isopen</span> <span class='hs-varop'>.</span> <span class='hs-varid'>prv</span>
<a name="line-610"></a> <span class='hs-varid'>vIsEOF</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>vTestOpen</span> <span class='hs-varid'>h</span>
<a name="line-611"></a> <span class='hs-varid'>mv</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vioc_get</span> <span class='hs-layout'>(</span><span class='hs-varid'>prv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span>
<a name="line-612"></a> <span class='hs-varid'>dat</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>readMVar</span> <span class='hs-varid'>mv</span>
<a name="line-613"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>dat</span> <span class='hs-varop'>==</span> <span class='hs-conid'>PipeEOF</span><span class='hs-layout'>)</span>
<a name="line-614"></a>
<a name="line-615"></a> <span class='hs-varid'>vGetChar</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>vTestEOF</span> <span class='hs-varid'>h</span>
<a name="line-616"></a> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>pr_getc</span> <span class='hs-varid'>h</span>
<a name="line-617"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>c</span> <span class='hs-keyword'>of</span>
<a name="line-618"></a> <span class='hs-conid'>PipeBit</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-varid'>x</span>
<a name="line-619"></a> <span class='hs-comment'>-- vTestEOF should eliminate this case</span>
<a name="line-620"></a> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>fail</span> <span class='hs-str'>"Internal error in HVIOReader vGetChar"</span>
<a name="line-621"></a> <span class='hs-varid'>vGetContents</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span>
<a name="line-622"></a> <span class='hs-keyword'>let</span> <span class='hs-varid'>loop</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>pr_getc</span> <span class='hs-varid'>h</span>
<a name="line-623"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>c</span> <span class='hs-keyword'>of</span>
<a name="line-624"></a> <span class='hs-conid'>PipeEOF</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-conid'>[]</span>
<a name="line-625"></a> <span class='hs-conid'>PipeBit</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span> <span class='hs-varid'>next</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>loop</span>
<a name="line-626"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span> <span class='hs-conop'>:</span> <span class='hs-varid'>next</span><span class='hs-layout'>)</span>
<a name="line-627"></a> <span class='hs-keyword'>in</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>vTestEOF</span> <span class='hs-varid'>h</span>
<a name="line-628"></a> <span class='hs-varid'>loop</span>
<a name="line-629"></a> <span class='hs-varid'>vIsReadable</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>True</span>
<a name="line-630"></a>
<a name="line-631"></a><a name="pwv"></a><span class='hs-comment'>------------------------------</span>
<a name="line-632"></a><span class='hs-comment'>-- Pipe Writer</span>
<a name="line-633"></a><span class='hs-comment'>------------------------------</span>
<a name="line-634"></a><span class='hs-definition'>pwv</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>PipeWriter</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>VIOCloseSupport</span> <span class='hs-conid'>PipeReader</span>
<a name="line-635"></a><span class='hs-definition'>pwv</span> <span class='hs-layout'>(</span><span class='hs-conid'>PipeWriter</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>x</span>
<a name="line-636"></a>
<a name="line-637"></a><a name="pwmv"></a><span class='hs-definition'>pwmv</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>PipeWriter</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-layout'>(</span><span class='hs-conid'>MVar</span> <span class='hs-conid'>PipeBit</span><span class='hs-layout'>)</span>
<a name="line-638"></a><span class='hs-definition'>pwmv</span> <span class='hs-layout'>(</span><span class='hs-conid'>PipeWriter</span> <span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>mv1</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vioc_get</span> <span class='hs-varid'>x</span>
<a name="line-639"></a> <span class='hs-varid'>vioc_get</span> <span class='hs-layout'>(</span><span class='hs-varid'>prv</span> <span class='hs-varid'>mv1</span><span class='hs-layout'>)</span>
<a name="line-640"></a>
<a name="line-641"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>Show</span> <span class='hs-conid'>PipeWriter</span> <span class='hs-keyword'>where</span>
<a name="line-642"></a> <span class='hs-varid'>show</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-str'>"<PipeWriter>"</span>
<a name="line-643"></a>
<a name="line-644"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>HVIO</span> <span class='hs-conid'>PipeWriter</span> <span class='hs-keyword'>where</span>
<a name="line-645"></a> <span class='hs-varid'>vClose</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>o</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vIsOpen</span> <span class='hs-varid'>h</span>
<a name="line-646"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>o</span> <span class='hs-keyword'>then</span> <span class='hs-keyword'>do</span>
<a name="line-647"></a> <span class='hs-varid'>mv</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>pwmv</span> <span class='hs-varid'>h</span>
<a name="line-648"></a> <span class='hs-varid'>putMVar</span> <span class='hs-varid'>mv</span> <span class='hs-conid'>PipeEOF</span>
<a name="line-649"></a> <span class='hs-varid'>vioc_close</span> <span class='hs-layout'>(</span><span class='hs-varid'>pwv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span>
<a name="line-650"></a> <span class='hs-keyword'>else</span> <span class='hs-varid'>return</span> <span class='hs-conid'>()</span>
<a name="line-651"></a> <span class='hs-varid'>vIsOpen</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>vioc_isopen</span> <span class='hs-varop'>.</span> <span class='hs-varid'>pwv</span>
<a name="line-652"></a> <span class='hs-varid'>vIsEOF</span> <span class='hs-varid'>h</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>vTestOpen</span> <span class='hs-varid'>h</span>
<a name="line-653"></a> <span class='hs-varid'>return</span> <span class='hs-conid'>False</span>
<a name="line-654"></a>
<a name="line-655"></a> <span class='hs-comment'>-- FIXME: race condition below (could be closed after testing)</span>
<a name="line-656"></a> <span class='hs-varid'>vPutChar</span> <span class='hs-varid'>h</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>vTestOpen</span> <span class='hs-varid'>h</span>
<a name="line-657"></a> <span class='hs-varid'>child</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vioc_get</span> <span class='hs-layout'>(</span><span class='hs-varid'>pwv</span> <span class='hs-varid'>h</span><span class='hs-layout'>)</span>
<a name="line-658"></a> <span class='hs-varid'>copen</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>vIsOpen</span> <span class='hs-varid'>child</span>
<a name="line-659"></a> <span class='hs-keyword'>if</span> <span class='hs-varid'>copen</span>
<a name="line-660"></a> <span class='hs-keyword'>then</span> <span class='hs-keyword'>do</span> <span class='hs-varid'>mv</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>pwmv</span> <span class='hs-varid'>h</span>
<a name="line-661"></a> <span class='hs-varid'>putMVar</span> <span class='hs-varid'>mv</span> <span class='hs-layout'>(</span><span class='hs-conid'>PipeBit</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span>
<a name="line-662"></a> <span class='hs-keyword'>else</span> <span class='hs-varid'>fail</span> <span class='hs-str'>"PipeWriter: Couldn't write to pipe because child end is closed"</span>
<a name="line-663"></a> <span class='hs-varid'>vIsWritable</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-conid'>True</span>
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