Checking if frame is complete and access duration doesn't need a decode

Source/core/platform/image-decoders/gif/GIFImageDecoder.cpp

 /*
  * Copyright (C) 2006 Apple Computer, Inc.  All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 109 matching lines @@
 
     ImageFrame& frame = m_frameBufferCache[index];
     if (frame.status() != ImageFrame::FrameComplete) {
         PlatformInstrumentation::willDecodeImage("GIF");
         decode(index + 1, GIFFullQuery);
         PlatformInstrumentation::didDecodeImage();
     }
     return &frame;
 }
 
+bool GIFImageDecoder::frameIsCompleteAtIndex(size_t index) const
+{
+    return m_reader && (index < m_reader->imagesCount()) && m_reader->frameContext(index)->isComplete();
+}
+
+float GIFImageDecoder::frameDurationAtIndex(size_t index) const
+{
+    return (m_reader && (index < m_reader->imagesCount()) &&
+        m_reader->frameContext(index)->isHeaderDefined()) ?
+        m_reader->frameContext(index)->delayTime : 0;
+}
+
 bool GIFImageDecoder::setFailed()
 {
     m_reader.clear();
     return ImageDecoder::setFailed();
 }
 
 void GIFImageDecoder::clearFrameBufferCache(size_t clearBeforeFrame)
 {
     // In some cases, like if the decoder was destroyed while animating, we
     // can be asked to clear more frames than we currently have.
@@ skipping 38 matching lines @@
     // Now |i| holds the last frame we need to preserve; clear prior frames.
     for (Vector<ImageFrame>::iterator j(m_frameBufferCache.begin()); j != i; ++j) {
         ASSERT(j->status() != ImageFrame::FramePartial);
         if (j->status() != ImageFrame::FrameEmpty)
             j->clearPixelData();
     }
 }
 
 bool GIFImageDecoder::haveDecodedRow(unsigned frameIndex, const Vector<unsigned char>& rowBuffer, size_t width, size_t rowNumber, unsigned repeatCount, bool writeTransparentPixels)
 {
-    const GIFFrameContext* frameContext = m_reader->frameContext();
+    const GIFFrameContext* frameContext = m_reader->frameContext(frameIndex);
     // The pixel data and coordinates supplied to us are relative to the frame's
     // origin within the entire image size, i.e.
     // (frameContext->xOffset, frameContext->yOffset). There is no guarantee
     // that width == (size().width() - frameContext->xOffset), so
     // we must ensure we don't run off the end of either the source data or the
     // row's X-coordinates.
     int xBegin = upperBoundScaledX(frameContext->xOffset);
     int yBegin = upperBoundScaledY(frameContext->yOffset + rowNumber);
     int xEnd = lowerBoundScaledX(std::min(static_cast<int>(frameContext->xOffset + width), size().width()) - 1, xBegin + 1) + 1;
     int yEnd = lowerBoundScaledY(std::min(static_cast<int>(frameContext->yOffset + rowNumber + repeatCount), size().height()) - 1, yBegin + 1) + 1;
@@ skipping 91 matching lines @@
     }
 
     return true;
 }
 
 void GIFImageDecoder::gifComplete()
 {
     // Cache the repetition count, which is now as authoritative as it's ever
     // going to be.
     repetitionCount();
-
-    m_reader.clear();
 }
 
 void GIFImageDecoder::decode(unsigned haltAtFrame, GIFQuery query)
 {
     if (failed())
         return;
 
     if (!m_reader) {
         m_reader = adoptPtr(new GIFImageReader(this));
         m_reader->setData(m_data);
@@ skipping 16 matching lines @@
         m_frameBufferCache[i].setPremultiplyAlpha(m_premultiplyAlpha);
 
     if (query == GIFFrameCountQuery)
         return;
 
     if (!m_reader->decode(GIFFullQuery, haltAtFrame)) {
         setFailed();
         return;
     }
 
-    // It is also a fatal error if all data is received but we failed to decode
-    // all frames completely.
-    if (isAllDataReceived() && haltAtFrame >= m_frameBufferCache.size() && m_reader)
+    // It is also a fatal error if all data is received and we have decoded all
+    // frames available but the file is truncated.
+    if (haltAtFrame >= m_frameBufferCache.size() && isAllDataReceived() && m_reader && !m_reader->parseCompleted())
         setFailed();
 }
 
 bool GIFImageDecoder::initFrameBuffer(unsigned frameIndex)
 {
     // Initialize the frame rect in our buffer.
-    const GIFFrameContext* frameContext = m_reader->frameContext();
+    const GIFFrameContext* frameContext = m_reader->frameContext(frameIndex);
     IntRect frameRect(frameContext->xOffset, frameContext->yOffset, frameContext->width, frameContext->height);
 
     // Make sure the frameRect doesn't extend outside the buffer.
     if (frameRect.maxX() > size().width())
         frameRect.setWidth(size().width() - frameContext->xOffset);
     if (frameRect.maxY() > size().height())
         frameRect.setHeight(size().height() - frameContext->yOffset);
 
     ImageFrame* const buffer = &m_frameBufferCache[frameIndex];
     int left = upperBoundScaledX(frameRect.x());
@@ skipping 53 matching lines @@
 
     // Update our status to be partially complete.
     buffer->setStatus(ImageFrame::FramePartial);
 
     // Reset the alpha pixel tracker for this frame.
     m_currentBufferSawAlpha = false;
     return true;
 }
 
 } // namespace WebCore