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<dt>Revision</dt> <dd><a href="http://trac.webkit.org/projects/webkit/changeset/208881">208881</a></dd>
<dt>Author</dt> <dd>carlosgc@webkit.org</dd>
<dt>Date</dt> <dd>2016-11-17 23:25:42 -0800 (Thu, 17 Nov 2016)</dd>
</dl>
<h3>Log Message</h3>
<pre>REGRESSION(<a href="http://trac.webkit.org/projects/webkit/changeset/208511">r208511</a>): ImageDecoders: Crash decoding GIF images since <a href="http://trac.webkit.org/projects/webkit/changeset/208511">r208511</a>
https://bugs.webkit.org/show_bug.cgi?id=164864
Reviewed by Simon Fraser.
This happens sometimes since <a href="http://trac.webkit.org/projects/webkit/changeset/208511">r208511</a> because the same decoder is used by more than one thread at the same
time and the decoders are not thread-safe. Several methods in ImageDecoder need to decode partially the image,
so it's possible that one method calls frameBufferAtIndex at the same times as createFrameImageAtIndex that now
can be called from the image decoder thread. Use a Lock in ImageDecoder to protect calls to frameBufferAtIndex.
* platform/image-decoders/ImageDecoder.cpp:
(WebCore::ImageDecoder::frameIsCompleteAtIndex):
(WebCore::ImageDecoder::frameDurationAtIndex):
(WebCore::ImageDecoder::createFrameImageAtIndex):
* platform/image-decoders/ImageDecoder.h:</pre>
<h3>Modified Paths</h3>
<ul>
<li><a href="#trunkSourceWebCoreChangeLog">trunk/Source/WebCore/ChangeLog</a></li>
<li><a href="#trunkSourceWebCoreplatformimagedecodersImageDecodercpp">trunk/Source/WebCore/platform/image-decoders/ImageDecoder.cpp</a></li>
<li><a href="#trunkSourceWebCoreplatformimagedecodersImageDecoderh">trunk/Source/WebCore/platform/image-decoders/ImageDecoder.h</a></li>
</ul>
</div>
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<h3>Diff</h3>
<a id="trunkSourceWebCoreChangeLog"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/ChangeLog (208880 => 208881)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/ChangeLog 2016-11-18 07:21:37 UTC (rev 208880)
+++ trunk/Source/WebCore/ChangeLog 2016-11-18 07:25:42 UTC (rev 208881)
</span><span class="lines">@@ -1,3 +1,21 @@
</span><ins>+2016-11-17 Carlos Garcia Campos <cgarcia@igalia.com>
+
+ REGRESSION(r208511): ImageDecoders: Crash decoding GIF images since r208511
+ https://bugs.webkit.org/show_bug.cgi?id=164864
+
+ Reviewed by Simon Fraser.
+
+ This happens sometimes since r208511 because the same decoder is used by more than one thread at the same
+ time and the decoders are not thread-safe. Several methods in ImageDecoder need to decode partially the image,
+ so it's possible that one method calls frameBufferAtIndex at the same times as createFrameImageAtIndex that now
+ can be called from the image decoder thread. Use a Lock in ImageDecoder to protect calls to frameBufferAtIndex.
+
+ * platform/image-decoders/ImageDecoder.cpp:
+ (WebCore::ImageDecoder::frameIsCompleteAtIndex):
+ (WebCore::ImageDecoder::frameDurationAtIndex):
+ (WebCore::ImageDecoder::createFrameImageAtIndex):
+ * platform/image-decoders/ImageDecoder.h:
+
</ins><span class="cx"> 2016-11-17 Ryosuke Niwa <rniwa@webkit.org>
</span><span class="cx">
</span><span class="cx"> Add an experimental API to find elements across shadow boundaries
</span></span></pre></div>
<a id="trunkSourceWebCoreplatformimagedecodersImageDecodercpp"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/platform/image-decoders/ImageDecoder.cpp (208880 => 208881)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/platform/image-decoders/ImageDecoder.cpp 2016-11-18 07:21:37 UTC (rev 208880)
+++ trunk/Source/WebCore/platform/image-decoders/ImageDecoder.cpp 2016-11-18 07:25:42 UTC (rev 208881)
</span><span class="lines">@@ -170,6 +170,7 @@
</span><span class="cx">
</span><span class="cx"> bool ImageDecoder::frameIsCompleteAtIndex(size_t index)
</span><span class="cx"> {
</span><ins>+ LockHolder locker(m_lock);
</ins><span class="cx"> ImageFrame* buffer = frameBufferAtIndex(index);
</span><span class="cx"> return buffer && buffer->isComplete();
</span><span class="cx"> }
</span><span class="lines">@@ -193,6 +194,7 @@
</span><span class="cx">
</span><span class="cx"> float ImageDecoder::frameDurationAtIndex(size_t index)
</span><span class="cx"> {
</span><ins>+ LockHolder locker(m_lock);
</ins><span class="cx"> ImageFrame* buffer = frameBufferAtIndex(index);
</span><span class="cx"> if (!buffer || buffer->isEmpty())
</span><span class="cx"> return 0;
</span><span class="lines">@@ -213,6 +215,7 @@
</span><span class="cx"> if (size().isEmpty())
</span><span class="cx"> return nullptr;
</span><span class="cx">
</span><ins>+ LockHolder locker(m_lock);
</ins><span class="cx"> ImageFrame* buffer = frameBufferAtIndex(index);
</span><span class="cx"> if (!buffer || buffer->isEmpty() || !buffer->hasBackingStore())
</span><span class="cx"> return nullptr;
</span></span></pre></div>
<a id="trunkSourceWebCoreplatformimagedecodersImageDecoderh"></a>
<div class="modfile"><h4>Modified: trunk/Source/WebCore/platform/image-decoders/ImageDecoder.h (208880 => 208881)</h4>
<pre class="diff"><span>
<span class="info">--- trunk/Source/WebCore/platform/image-decoders/ImageDecoder.h 2016-11-18 07:21:37 UTC (rev 208880)
+++ trunk/Source/WebCore/platform/image-decoders/ImageDecoder.h 2016-11-18 07:25:42 UTC (rev 208881)
</span><span class="lines">@@ -34,6 +34,7 @@
</span><span class="cx"> #include "PlatformScreen.h"
</span><span class="cx"> #include "SharedBuffer.h"
</span><span class="cx"> #include <wtf/Assertions.h>
</span><ins>+#include <wtf/Lock.h>
</ins><span class="cx"> #include <wtf/Optional.h>
</span><span class="cx"> #include <wtf/RefPtr.h>
</span><span class="cx"> #include <wtf/Vector.h>
</span><span class="lines">@@ -214,6 +215,7 @@
</span><span class="cx"> #endif
</span><span class="cx"> bool m_isAllDataReceived { false };
</span><span class="cx"> bool m_failed { false };
</span><ins>+ Lock m_lock;
</ins><span class="cx"> };
</span><span class="cx">
</span><span class="cx"> } // namespace WebCore
</span></span></pre>
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