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<title>Blaze/ByteString/Builder/Internal/Buffer.hs</title>
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<pre><a name="line-1"></a><span class='hs-comment'>{-# LANGUAGE CPP, BangPatterns, Rank2Types, MonoPatBinds #-}</span>
<a name="line-2"></a><span class='hs-comment'>-- |</span>
<a name="line-3"></a><span class='hs-comment'>-- Module : Blaze.ByteString.Builder.Internal.Buffer</span>
<a name="line-4"></a><span class='hs-comment'>-- Copyright : (c) 2010 Simon Meier</span>
<a name="line-5"></a><span class='hs-comment'>-- License : BSD3-style (see LICENSE)</span>
<a name="line-6"></a><span class='hs-comment'>-- </span>
<a name="line-7"></a><span class='hs-comment'>-- Maintainer : Simon Meier <iridcode@gmail.com></span>
<a name="line-8"></a><span class='hs-comment'>-- Stability : experimental</span>
<a name="line-9"></a><span class='hs-comment'>-- Portability : tested on GHC only</span>
<a name="line-10"></a><span class='hs-comment'>--</span>
<a name="line-11"></a><span class='hs-comment'>-- Execution of the 'Put' monad and hence also 'Builder's with respect to</span>
<a name="line-12"></a><span class='hs-comment'>-- buffers.</span>
<a name="line-13"></a><span class='hs-comment'>--</span>
<a name="line-14"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Blaze</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span><span class='hs-varop'>.</span><span class='hs-conid'>Builder</span><span class='hs-varop'>.</span><span class='hs-conid'>Internal</span><span class='hs-varop'>.</span><span class='hs-conid'>Buffer</span> <span class='hs-layout'>(</span>
<a name="line-15"></a> <span class='hs-comment'>-- * Buffers</span>
<a name="line-16"></a> <span class='hs-conid'>Buffer</span>
<a name="line-17"></a>
<a name="line-18"></a> <span class='hs-comment'>-- ** Status information</span>
<a name="line-19"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>freeSize</span>
<a name="line-20"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>sliceSize</span>
<a name="line-21"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>bufferSize</span>
<a name="line-22"></a>
<a name="line-23"></a> <span class='hs-comment'>-- ** Creation and modification</span>
<a name="line-24"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>allocBuffer</span>
<a name="line-25"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>reuseBuffer</span>
<a name="line-26"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>nextSlice</span>
<a name="line-27"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>updateEndOfSlice</span>
<a name="line-28"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>execBuildStep</span>
<a name="line-29"></a>
<a name="line-30"></a> <span class='hs-comment'>-- ** Conversion to bytestings</span>
<a name="line-31"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>unsafeFreezeBuffer</span>
<a name="line-32"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>unsafeFreezeNonEmptyBuffer</span>
<a name="line-33"></a>
<a name="line-34"></a> <span class='hs-comment'>-- * Buffer allocation strategies</span>
<a name="line-35"></a> <span class='hs-layout'>,</span> <span class='hs-conid'>BufferAllocStrategy</span>
<a name="line-36"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>allNewBuffersStrategy</span>
<a name="line-37"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>reuseBufferStrategy</span>
<a name="line-38"></a>
<a name="line-39"></a> <span class='hs-comment'>-- * Executing puts respect to some monad</span>
<a name="line-40"></a> <span class='hs-layout'>,</span> <span class='hs-varid'>runPut</span>
<a name="line-41"></a> <span class='hs-layout'>)</span> <span class='hs-keyword'>where</span>
<a name="line-42"></a>
<a name="line-43"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Prelude</span>
<a name="line-44"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Foreign</span>
<a name="line-45"></a>
<a name="line-46"></a><span class='hs-keyword'>import</span> <span class='hs-keyword'>qualified</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>S</span>
<a name="line-47"></a>
<a name="line-48"></a><span class='hs-cpp'>#ifdef BYTESTRING_IN_BASE</span>
<a name="line-49"></a><span class='hs-keyword'>import</span> <span class='hs-keyword'>qualified</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span><span class='hs-varop'>.</span><span class='hs-conid'>Base</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>S</span>
<a name="line-50"></a><span class='hs-cpp'>#else</span>
<a name="line-51"></a><span class='hs-keyword'>import</span> <span class='hs-keyword'>qualified</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span><span class='hs-varop'>.</span><span class='hs-conid'>Internal</span> <span class='hs-keyword'>as</span> <span class='hs-conid'>S</span>
<a name="line-52"></a><span class='hs-cpp'>#endif</span>
<a name="line-53"></a>
<a name="line-54"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Blaze</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span><span class='hs-varop'>.</span><span class='hs-conid'>Builder</span><span class='hs-varop'>.</span><span class='hs-conid'>Internal</span><span class='hs-varop'>.</span><span class='hs-conid'>Types</span>
<a name="line-55"></a><span class='hs-comment'>------------------------------------------------------------------------------</span>
<a name="line-56"></a><span class='hs-comment'>-- Buffers</span>
<a name="line-57"></a><span class='hs-comment'>------------------------------------------------------------------------------</span>
<a name="line-58"></a>
<a name="line-59"></a><a name="Buffer"></a><span class='hs-comment'>-- | A buffer @Buffer fpbuf p0 op ope@ describes a buffer with the underlying</span>
<a name="line-60"></a><a name="Buffer"></a><span class='hs-comment'>-- byte array @fpbuf..ope@, the currently written slice @p0..op@ and the free</span>
<a name="line-61"></a><a name="Buffer"></a><span class='hs-comment'>-- space @op..ope@.</span>
<a name="line-62"></a><a name="Buffer"></a><span class='hs-keyword'>data</span> <span class='hs-conid'>Buffer</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Buffer</span> <span class='hs-comment'>{-# UNPACK #-}</span> <span class='hs-varop'>!</span><span class='hs-layout'>(</span><span class='hs-conid'>ForeignPtr</span> <span class='hs-conid'>Word8</span><span class='hs-layout'>)</span> <span class='hs-comment'>-- underlying pinned array</span>
<a name="line-63"></a> <span class='hs-comment'>{-# UNPACK #-}</span> <span class='hs-varop'>!</span><span class='hs-layout'>(</span><span class='hs-conid'>Ptr</span> <span class='hs-conid'>Word8</span><span class='hs-layout'>)</span> <span class='hs-comment'>-- beginning of slice</span>
<a name="line-64"></a> <span class='hs-comment'>{-# UNPACK #-}</span> <span class='hs-varop'>!</span><span class='hs-layout'>(</span><span class='hs-conid'>Ptr</span> <span class='hs-conid'>Word8</span><span class='hs-layout'>)</span> <span class='hs-comment'>-- next free byte</span>
<a name="line-65"></a> <span class='hs-comment'>{-# UNPACK #-}</span> <span class='hs-varop'>!</span><span class='hs-layout'>(</span><span class='hs-conid'>Ptr</span> <span class='hs-conid'>Word8</span><span class='hs-layout'>)</span> <span class='hs-comment'>-- first byte after buffer</span>
<a name="line-66"></a>
<a name="line-67"></a><a name="freeSize"></a><span class='hs-comment'>-- | The size of the free space of the buffer.</span>
<a name="line-68"></a><span class='hs-definition'>freeSize</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Buffer</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Int</span>
<a name="line-69"></a><span class='hs-definition'>freeSize</span> <span class='hs-layout'>(</span><span class='hs-conid'>Buffer</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>op</span> <span class='hs-varid'>ope</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>ope</span> <span class='hs-varop'>`minusPtr`</span> <span class='hs-varid'>op</span>
<a name="line-70"></a>
<a name="line-71"></a><a name="sliceSize"></a><span class='hs-comment'>-- | The size of the written slice in the buffer.</span>
<a name="line-72"></a><span class='hs-definition'>sliceSize</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Buffer</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Int</span>
<a name="line-73"></a><span class='hs-definition'>sliceSize</span> <span class='hs-layout'>(</span><span class='hs-conid'>Buffer</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>op</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>op</span> <span class='hs-varop'>`minusPtr`</span> <span class='hs-varid'>p0</span>
<a name="line-74"></a>
<a name="line-75"></a><a name="bufferSize"></a><span class='hs-comment'>-- | The size of the whole byte array underlying the buffer.</span>
<a name="line-76"></a><span class='hs-definition'>bufferSize</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Buffer</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Int</span>
<a name="line-77"></a><span class='hs-definition'>bufferSize</span> <span class='hs-layout'>(</span><span class='hs-conid'>Buffer</span> <span class='hs-varid'>fpbuf</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>ope</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-78"></a> <span class='hs-varid'>ope</span> <span class='hs-varop'>`minusPtr`</span> <span class='hs-varid'>unsafeForeignPtrToPtr</span> <span class='hs-varid'>fpbuf</span>
<a name="line-79"></a>
<a name="line-80"></a><a name="allocBuffer"></a><span class='hs-comment'>-- | @allocBuffer size@ allocates a new buffer of size @size@.</span>
<a name="line-81"></a><span class='hs-comment'>{-# INLINE allocBuffer #-}</span>
<a name="line-82"></a><span class='hs-definition'>allocBuffer</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'>Buffer</span>
<a name="line-83"></a><span class='hs-definition'>allocBuffer</span> <span class='hs-varid'>size</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-84"></a> <span class='hs-varid'>fpbuf</span> <span class='hs-keyglyph'><-</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>mallocByteString</span> <span class='hs-varid'>size</span>
<a name="line-85"></a> <span class='hs-keyword'>let</span> <span class='hs-varop'>!</span><span class='hs-varid'>pbuf</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unsafeForeignPtrToPtr</span> <span class='hs-varid'>fpbuf</span>
<a name="line-86"></a> <span class='hs-varid'>return</span> <span class='hs-varop'>$!</span> <span class='hs-conid'>Buffer</span> <span class='hs-varid'>fpbuf</span> <span class='hs-varid'>pbuf</span> <span class='hs-varid'>pbuf</span> <span class='hs-layout'>(</span><span class='hs-varid'>pbuf</span> <span class='hs-varop'>`plusPtr`</span> <span class='hs-varid'>size</span><span class='hs-layout'>)</span>
<a name="line-87"></a>
<a name="line-88"></a><a name="reuseBuffer"></a><span class='hs-comment'>-- | Resets the beginning of the next slice and the next free byte such that</span>
<a name="line-89"></a><span class='hs-comment'>-- the whole buffer can be filled again.</span>
<a name="line-90"></a><span class='hs-comment'>{-# INLINE reuseBuffer #-}</span>
<a name="line-91"></a><span class='hs-definition'>reuseBuffer</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Buffer</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Buffer</span>
<a name="line-92"></a><span class='hs-definition'>reuseBuffer</span> <span class='hs-layout'>(</span><span class='hs-conid'>Buffer</span> <span class='hs-varid'>fpbuf</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>ope</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Buffer</span> <span class='hs-varid'>fpbuf</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>ope</span>
<a name="line-93"></a> <span class='hs-keyword'>where</span>
<a name="line-94"></a> <span class='hs-varid'>p0</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>unsafeForeignPtrToPtr</span> <span class='hs-varid'>fpbuf</span>
<a name="line-95"></a>
<a name="line-96"></a><a name="unsafeFreezeBuffer"></a><span class='hs-comment'>-- | Convert the buffer to a bytestring. This operation is unsafe in the sense</span>
<a name="line-97"></a><span class='hs-comment'>-- that created bytestring shares the underlying byte array with the buffer.</span>
<a name="line-98"></a><span class='hs-comment'>-- Hence, depending on the later use of this buffer (e.g., if it gets reset and</span>
<a name="line-99"></a><span class='hs-comment'>-- filled again) referential transparency may be lost.</span>
<a name="line-100"></a><span class='hs-comment'>{-# INLINE unsafeFreezeBuffer #-}</span>
<a name="line-101"></a><span class='hs-definition'>unsafeFreezeBuffer</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Buffer</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span>
<a name="line-102"></a><span class='hs-definition'>unsafeFreezeBuffer</span> <span class='hs-layout'>(</span><span class='hs-conid'>Buffer</span> <span class='hs-varid'>fpbuf</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>op</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-103"></a> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>PS</span> <span class='hs-varid'>fpbuf</span> <span class='hs-layout'>(</span><span class='hs-varid'>p0</span> <span class='hs-varop'>`minusPtr`</span> <span class='hs-varid'>unsafeForeignPtrToPtr</span> <span class='hs-varid'>fpbuf</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>op</span> <span class='hs-varop'>`minusPtr`</span> <span class='hs-varid'>p0</span><span class='hs-layout'>)</span>
<a name="line-104"></a>
<a name="line-105"></a><a name="unsafeFreezeNonEmptyBuffer"></a><span class='hs-comment'>-- | Convert a buffer to a non-empty bytestring. See 'unsafeFreezeBuffer' for</span>
<a name="line-106"></a><span class='hs-comment'>-- the explanation of why this operation may be unsafe.</span>
<a name="line-107"></a><span class='hs-comment'>{-# INLINE unsafeFreezeNonEmptyBuffer #-}</span>
<a name="line-108"></a><span class='hs-definition'>unsafeFreezeNonEmptyBuffer</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Buffer</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span>
<a name="line-109"></a><span class='hs-definition'>unsafeFreezeNonEmptyBuffer</span> <span class='hs-varid'>buf</span>
<a name="line-110"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>sliceSize</span> <span class='hs-varid'>buf</span> <span class='hs-varop'><=</span> <span class='hs-num'>0</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-111"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-varop'>$</span> <span class='hs-varid'>unsafeFreezeBuffer</span> <span class='hs-varid'>buf</span>
<a name="line-112"></a>
<a name="line-113"></a><a name="updateEndOfSlice"></a><span class='hs-comment'>-- | Update the end of slice pointer.</span>
<a name="line-114"></a><span class='hs-comment'>{-# INLINE updateEndOfSlice #-}</span>
<a name="line-115"></a><span class='hs-definition'>updateEndOfSlice</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Buffer</span> <span class='hs-comment'>-- Old buffer</span>
<a name="line-116"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Ptr</span> <span class='hs-conid'>Word8</span> <span class='hs-comment'>-- New end of slice </span>
<a name="line-117"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Buffer</span> <span class='hs-comment'>-- Updated buffer</span>
<a name="line-118"></a><span class='hs-definition'>updateEndOfSlice</span> <span class='hs-layout'>(</span><span class='hs-conid'>Buffer</span> <span class='hs-varid'>fpbuf</span> <span class='hs-varid'>p0</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>ope</span><span class='hs-layout'>)</span> <span class='hs-varid'>op'</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Buffer</span> <span class='hs-varid'>fpbuf</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>op'</span> <span class='hs-varid'>ope</span>
<a name="line-119"></a>
<a name="line-120"></a><a name="execBuildStep"></a><span class='hs-comment'>-- | Execute a build step on the given buffer.</span>
<a name="line-121"></a><span class='hs-comment'>{-# INLINE execBuildStep #-}</span>
<a name="line-122"></a><span class='hs-definition'>execBuildStep</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>BuildStep</span> <span class='hs-varid'>a</span>
<a name="line-123"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Buffer</span>
<a name="line-124"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-layout'>(</span><span class='hs-conid'>BuildSignal</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-125"></a><span class='hs-definition'>execBuildStep</span> <span class='hs-varid'>step</span> <span class='hs-layout'>(</span><span class='hs-conid'>Buffer</span> <span class='hs-keyword'>_</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>op</span> <span class='hs-varid'>ope</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>runBuildStep</span> <span class='hs-varid'>step</span> <span class='hs-layout'>(</span><span class='hs-conid'>BufRange</span> <span class='hs-varid'>op</span> <span class='hs-varid'>ope</span><span class='hs-layout'>)</span>
<a name="line-126"></a>
<a name="line-127"></a><a name="nextSlice"></a><span class='hs-comment'>-- | Move the beginning of the slice to the next free byte such that the</span>
<a name="line-128"></a><span class='hs-comment'>-- remaining free space of the buffer can be filled further. This operation</span>
<a name="line-129"></a><span class='hs-comment'>-- is safe and can be used to fill the remaining part of the buffer after a</span>
<a name="line-130"></a><span class='hs-comment'>-- direct insertion of a bytestring or a flush.</span>
<a name="line-131"></a><span class='hs-comment'>{-# INLINE nextSlice #-}</span>
<a name="line-132"></a><span class='hs-definition'>nextSlice</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Buffer</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Maybe</span> <span class='hs-conid'>Buffer</span>
<a name="line-133"></a><span class='hs-definition'>nextSlice</span> <span class='hs-varid'>minSize</span> <span class='hs-layout'>(</span><span class='hs-conid'>Buffer</span> <span class='hs-varid'>fpbuf</span> <span class='hs-keyword'>_</span> <span class='hs-varid'>op</span> <span class='hs-varid'>ope</span><span class='hs-layout'>)</span>
<a name="line-134"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>ope</span> <span class='hs-varop'>`minusPtr`</span> <span class='hs-varid'>op</span> <span class='hs-varop'><=</span> <span class='hs-varid'>minSize</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Nothing</span>
<a name="line-135"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Just</span> <span class='hs-layout'>(</span><span class='hs-conid'>Buffer</span> <span class='hs-varid'>fpbuf</span> <span class='hs-varid'>op</span> <span class='hs-varid'>op</span> <span class='hs-varid'>ope</span><span class='hs-layout'>)</span>
<a name="line-136"></a>
<a name="line-137"></a><span class='hs-comment'>------------------------------------------------------------------------------</span>
<a name="line-138"></a><span class='hs-comment'>-- Buffer allocation strategies</span>
<a name="line-139"></a><span class='hs-comment'>------------------------------------------------------------------------------</span>
<a name="line-140"></a>
<a name="line-141"></a><a name="BufferAllocStrategy"></a><span class='hs-comment'>-- | A buffer allocation strategy @(buf0, nextBuf)@ specifies the initial</span>
<a name="line-142"></a><a name="BufferAllocStrategy"></a><span class='hs-comment'>-- buffer to use and how to compute a new buffer @nextBuf minSize buf@ with at</span>
<a name="line-143"></a><a name="BufferAllocStrategy"></a><span class='hs-comment'>-- least size @minSize@ from a filled buffer @buf@. The double nesting of the</span>
<a name="line-144"></a><a name="BufferAllocStrategy"></a><span class='hs-comment'>-- @IO@ monad helps to ensure that the reference to the filled buffer @buf@ is</span>
<a name="line-145"></a><a name="BufferAllocStrategy"></a><span class='hs-comment'>-- lost as soon as possible, but the new buffer doesn't have to be allocated </span>
<a name="line-146"></a><a name="BufferAllocStrategy"></a><span class='hs-comment'>-- too early.</span>
<a name="line-147"></a><a name="BufferAllocStrategy"></a><span class='hs-keyword'>type</span> <span class='hs-conid'>BufferAllocStrategy</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-conid'>IO</span> <span class='hs-conid'>Buffer</span><span class='hs-layout'>,</span> <span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Buffer</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>IO</span> <span class='hs-layout'>(</span><span class='hs-conid'>IO</span> <span class='hs-conid'>Buffer</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-148"></a>
<a name="line-149"></a><a name="allNewBuffersStrategy"></a><span class='hs-comment'>-- | The simplest buffer allocation strategy: whenever a buffer is requested,</span>
<a name="line-150"></a><span class='hs-comment'>-- allocate a new one that is big enough for the next build step to execute.</span>
<a name="line-151"></a><span class='hs-comment'>--</span>
<a name="line-152"></a><span class='hs-comment'>-- NOTE that this allocation strategy may spill quite some memory upon direct</span>
<a name="line-153"></a><span class='hs-comment'>-- insertion of a bytestring by the builder. Thats no problem for garbage</span>
<a name="line-154"></a><span class='hs-comment'>-- collection, but it may lead to unreasonably high memory consumption in</span>
<a name="line-155"></a><span class='hs-comment'>-- special circumstances.</span>
<a name="line-156"></a><span class='hs-definition'>allNewBuffersStrategy</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Int</span> <span class='hs-comment'>-- Minimal buffer size.</span>
<a name="line-157"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>BufferAllocStrategy</span>
<a name="line-158"></a><span class='hs-definition'>allNewBuffersStrategy</span> <span class='hs-varid'>bufSize</span> <span class='hs-keyglyph'>=</span>
<a name="line-159"></a> <span class='hs-layout'>(</span> <span class='hs-varid'>allocBuffer</span> <span class='hs-varid'>bufSize</span>
<a name="line-160"></a> <span class='hs-layout'>,</span> <span class='hs-keyglyph'>\</span><span class='hs-varid'>reqSize</span> <span class='hs-keyword'>_</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>allocBuffer</span> <span class='hs-layout'>(</span><span class='hs-varid'>max</span> <span class='hs-varid'>reqSize</span> <span class='hs-varid'>bufSize</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-layout'>)</span>
<a name="line-161"></a>
<a name="line-162"></a><a name="reuseBufferStrategy"></a><span class='hs-comment'>-- | An unsafe, but possibly more efficient buffer allocation strategy:</span>
<a name="line-163"></a><span class='hs-comment'>-- reuse the buffer, if it is big enough for the next build step to execute.</span>
<a name="line-164"></a><span class='hs-definition'>reuseBufferStrategy</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>IO</span> <span class='hs-conid'>Buffer</span>
<a name="line-165"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>BufferAllocStrategy</span>
<a name="line-166"></a><span class='hs-definition'>reuseBufferStrategy</span> <span class='hs-varid'>buf0</span> <span class='hs-keyglyph'>=</span>
<a name="line-167"></a> <span class='hs-layout'>(</span><span class='hs-varid'>buf0</span><span class='hs-layout'>,</span> <span class='hs-varid'>tryReuseBuffer</span><span class='hs-layout'>)</span>
<a name="line-168"></a> <span class='hs-keyword'>where</span>
<a name="line-169"></a> <span class='hs-varid'>tryReuseBuffer</span> <span class='hs-varid'>reqSize</span> <span class='hs-varid'>buf</span>
<a name="line-170"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>bufferSize</span> <span class='hs-varid'>buf</span> <span class='hs-varop'>>=</span> <span class='hs-varid'>reqSize</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>reuseBuffer</span> <span class='hs-varid'>buf</span><span class='hs-layout'>)</span>
<a name="line-171"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-varid'>allocBuffer</span> <span class='hs-varid'>reqSize</span>
<a name="line-172"></a>
<a name="line-173"></a><span class='hs-comment'>------------------------------------------------------------------------------</span>
<a name="line-174"></a><span class='hs-comment'>-- Executing puts on a buffer</span>
<a name="line-175"></a><span class='hs-comment'>------------------------------------------------------------------------------</span>
<a name="line-176"></a>
<a name="line-177"></a>
<a name="line-178"></a><a name="runPut"></a><span class='hs-comment'>-- | Execute a put on a buffer.</span>
<a name="line-179"></a><span class='hs-comment'>--</span>
<a name="line-180"></a><span class='hs-comment'>-- TODO: Generalize over buffer allocation strategy.</span>
<a name="line-181"></a><span class='hs-comment'>{-# INLINE runPut #-}</span>
<a name="line-182"></a><span class='hs-definition'>runPut</span> <span class='hs-keyglyph'>::</span> <span class='hs-conid'>Monad</span> <span class='hs-varid'>m</span>
<a name="line-183"></a> <span class='hs-keyglyph'>=></span> <span class='hs-layout'>(</span><span class='hs-conid'>IO</span> <span class='hs-layout'>(</span><span class='hs-conid'>BuildSignal</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-conid'>BuildSignal</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-comment'>-- lifting of buildsteps</span>
<a name="line-184"></a> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>Int</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Buffer</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-conid'>Buffer</span><span class='hs-layout'>)</span> <span class='hs-comment'>-- output function for a guaranteedly non-empty buffer, the returned buffer will be filled next</span>
<a name="line-185"></a> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-conid'>ByteString</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-conid'>()</span><span class='hs-layout'>)</span> <span class='hs-comment'>-- output function for guaranteedly non-empty bytestrings, that are inserted directly into the stream</span>
<a name="line-186"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Put</span> <span class='hs-varid'>a</span> <span class='hs-comment'>-- put to execute</span>
<a name="line-187"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Buffer</span> <span class='hs-comment'>-- initial buffer to be used</span>
<a name="line-188"></a> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>m</span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Buffer</span><span class='hs-layout'>)</span> <span class='hs-comment'>-- result of put and remaining buffer</span>
<a name="line-189"></a><span class='hs-definition'>runPut</span> <span class='hs-varid'>liftIO</span> <span class='hs-varid'>outputBuf</span> <span class='hs-varid'>outputBS</span> <span class='hs-layout'>(</span><span class='hs-conid'>Put</span> <span class='hs-varid'>put</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-190"></a> <span class='hs-varid'>runStep</span> <span class='hs-layout'>(</span><span class='hs-varid'>put</span> <span class='hs-layout'>(</span><span class='hs-varid'>finalStep</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-191"></a> <span class='hs-keyword'>where</span>
<a name="line-192"></a> <span class='hs-varid'>finalStep</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>buildStep</span> <span class='hs-varop'>$</span> <span class='hs-keyglyph'>\</span><span class='hs-layout'>(</span><span class='hs-conid'>BufRange</span> <span class='hs-varid'>op</span> <span class='hs-keyword'>_</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>return</span> <span class='hs-varop'>$</span> <span class='hs-conid'>Done</span> <span class='hs-varid'>op</span> <span class='hs-varid'>x</span>
<a name="line-193"></a>
<a name="line-194"></a> <span class='hs-varid'>runStep</span> <span class='hs-varid'>step</span> <span class='hs-varid'>buf</span><span class='hs-keyglyph'>@</span><span class='hs-layout'>(</span><span class='hs-conid'>Buffer</span> <span class='hs-varid'>fpbuf</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>op</span> <span class='hs-varid'>ope</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-keyword'>do</span>
<a name="line-195"></a> <span class='hs-keyword'>let</span> <span class='hs-varop'>!</span><span class='hs-varid'>br</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>BufRange</span> <span class='hs-varid'>op</span> <span class='hs-varid'>ope</span>
<a name="line-196"></a> <span class='hs-varid'>signal</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>liftIO</span> <span class='hs-varop'>$</span> <span class='hs-varid'>runBuildStep</span> <span class='hs-varid'>step</span> <span class='hs-varid'>br</span>
<a name="line-197"></a> <span class='hs-keyword'>case</span> <span class='hs-varid'>signal</span> <span class='hs-keyword'>of</span>
<a name="line-198"></a> <span class='hs-conid'>Done</span> <span class='hs-varid'>op'</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>-></span> <span class='hs-comment'>-- put completed, buffer partially runSteped</span>
<a name="line-199"></a> <span class='hs-varid'>return</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-layout'>,</span> <span class='hs-conid'>Buffer</span> <span class='hs-varid'>fpbuf</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>op'</span> <span class='hs-varid'>ope</span><span class='hs-layout'>)</span>
<a name="line-200"></a>
<a name="line-201"></a> <span class='hs-conid'>BufferFull</span> <span class='hs-varid'>minSize</span> <span class='hs-varid'>op'</span> <span class='hs-varid'>nextStep</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span>
<a name="line-202"></a> <span class='hs-varid'>buf'</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>outputBuf</span> <span class='hs-varid'>minSize</span> <span class='hs-layout'>(</span><span class='hs-conid'>Buffer</span> <span class='hs-varid'>fpbuf</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>op'</span> <span class='hs-varid'>ope</span><span class='hs-layout'>)</span>
<a name="line-203"></a> <span class='hs-varid'>runStep</span> <span class='hs-varid'>nextStep</span> <span class='hs-varid'>buf'</span>
<a name="line-204"></a>
<a name="line-205"></a> <span class='hs-conid'>InsertByteString</span> <span class='hs-varid'>op'</span> <span class='hs-varid'>bs</span> <span class='hs-varid'>nextStep</span>
<a name="line-206"></a> <span class='hs-keyglyph'>|</span> <span class='hs-conid'>S</span><span class='hs-varop'>.</span><span class='hs-varid'>null</span> <span class='hs-varid'>bs</span> <span class='hs-keyglyph'>-></span> <span class='hs-comment'>-- flushing of buffer required</span>
<a name="line-207"></a> <span class='hs-varid'>outputBuf</span> <span class='hs-num'>1</span> <span class='hs-layout'>(</span><span class='hs-conid'>Buffer</span> <span class='hs-varid'>fpbuf</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>op'</span> <span class='hs-varid'>ope</span><span class='hs-layout'>)</span> <span class='hs-varop'>>>=</span> <span class='hs-varid'>runStep</span> <span class='hs-varid'>nextStep</span>
<a name="line-208"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>p0</span> <span class='hs-varop'>==</span> <span class='hs-varid'>op'</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span> <span class='hs-comment'>-- no bytes written: just insert bytestring</span>
<a name="line-209"></a> <span class='hs-varid'>outputBS</span> <span class='hs-varid'>bs</span>
<a name="line-210"></a> <span class='hs-varid'>runStep</span> <span class='hs-varid'>nextStep</span> <span class='hs-varid'>buf</span>
<a name="line-211"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>-></span> <span class='hs-keyword'>do</span> <span class='hs-comment'>-- bytes written, insert buffer and bytestring</span>
<a name="line-212"></a> <span class='hs-varid'>buf'</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>outputBuf</span> <span class='hs-num'>1</span> <span class='hs-layout'>(</span><span class='hs-conid'>Buffer</span> <span class='hs-varid'>fpbuf</span> <span class='hs-varid'>p0</span> <span class='hs-varid'>op'</span> <span class='hs-varid'>ope</span><span class='hs-layout'>)</span>
<a name="line-213"></a> <span class='hs-varid'>outputBS</span> <span class='hs-varid'>bs</span>
<a name="line-214"></a> <span class='hs-varid'>runStep</span> <span class='hs-varid'>nextStep</span> <span class='hs-varid'>buf'</span>
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