Blink image-decoders: (lazy) deferred image decoding support for ICO

third_party/WebKit/Source/platform/image-decoders/ico/ICOImageDecoder.cpp

 /*
  * Copyright (c) 2008, 2009, Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 67 matching lines @@
     return (index && (index < m_dirEntries.size())) ? m_dirEntries[index].m_size : size();
 }
 
 bool ICOImageDecoder::setSize(unsigned width, unsigned height)
 {
     // The size calculated inside the BMPImageReader had better match the one in
     // the icon directory.
     return m_frameSize.isEmpty() ? ImageDecoder::setSize(width, height) : ((IntSize(width, height) == m_frameSize) || setFailed());
 }
 
+bool ICOImageDecoder::frameIsCompleteAtIndex(size_t index) const
+{
+    if (index >= m_dirEntries.size())
+        return false;
+    const IconDirectoryEntry& dirEntry = m_dirEntries[index];
+    return (dirEntry.m_imageOffset + dirEntry.m_byteSize) <= m_data->size();
+}
+
 bool ICOImageDecoder::setFailed()
 {
     m_bmpReaders.clear();
     m_pngDecoders.clear();
     return ImageDecoder::setFailed();
 }
 
 bool ICOImageDecoder::hotSpot(IntPoint& hotSpot) const
 {
     // When unspecified, the default frame is always frame 0. This is consistent with
@@ skipping 17 matching lines @@
 {
     // Larger icons are better.  After that, higher bit-depth icons are better.
     const int aEntryArea = a.m_size.width() * a.m_size.height();
     const int bEntryArea = b.m_size.width() * b.m_size.height();
     return (aEntryArea == bEntryArea) ? (a.m_bitCount > b.m_bitCount) : (aEntryArea > bEntryArea);
 }
 
 size_t ICOImageDecoder::decodeFrameCount()
 {
     decodeSize();
+
+    // Length of sequence of completely received frames.
+    for (size_t i = 0; i < m_dirEntries.size(); ++i) {
+        const IconDirectoryEntry& dirEntry = m_dirEntries[i];
+        if ((dirEntry.m_imageOffset + dirEntry.m_byteSize) > m_data->size())
+            return i;
+    }
     return m_dirEntries.size();
 }
 
 void ICOImageDecoder::setDataForPNGDecoderAtIndex(size_t index)
 {
     if (!m_pngDecoders[index])
         return;
 
     m_pngDecoders[index]->setData(m_data.get(), isAllDataReceived());
 }
@@ skipping 33 matching lines @@
 bool ICOImageDecoder::decodeAtIndex(size_t index)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(index < m_dirEntries.size());
     const IconDirectoryEntry& dirEntry = m_dirEntries[index];
     const ImageType imageType = imageTypeAtIndex(index);
     if (imageType == Unknown)
         return false; // Not enough data to determine image type yet.
 
     if (imageType == BMP) {
         if (!m_bmpReaders[index]) {
-            // We need to have already sized m_frameBufferCache before this, and
-            // we must not resize it again later (see caution in frameCount()).
-            ASSERT(m_frameBufferCache.size() == m_dirEntries.size());
             m_bmpReaders[index] = adoptPtr(new BMPImageReader(this, dirEntry.m_imageOffset, 0, true));
             m_bmpReaders[index]->setData(m_data.get());
-            m_bmpReaders[index]->setBuffer(&m_frameBufferCache[index]);
         }
+        // Update the pointer to the buffer as it could change after
+        // m_frameBufferCache.resize().
+        m_bmpReaders[index]->setBuffer(&m_frameBufferCache[index]);
         m_frameSize = dirEntry.m_size;
         bool result = m_bmpReaders[index]->decodeBMP(false);
         m_frameSize = IntSize();
         return result;
     }
 
     if (!m_pngDecoders[index]) {
         AlphaOption alphaOption = m_premultiplyAlpha ? AlphaPremultiplied : AlphaNotPremultiplied;
         GammaAndColorProfileOption colorOptions = m_ignoreGammaAndColorProfile ? GammaAndColorProfileIgnored : GammaAndColorProfileApplied;
         m_pngDecoders[index] = adoptPtr(new PNGImageDecoder(alphaOption, colorOptions, m_maxDecodedBytes, dirEntry.m_imageOffset));
@@ skipping 78 matching lines @@
         height = 256;
     IconDirectoryEntry entry;
     entry.m_size = IntSize(width, height);
     if (m_fileType == CURSOR) {
         entry.m_bitCount = 0;
         entry.m_hotSpot = IntPoint(readUint16(4), readUint16(6));
     } else {
         entry.m_bitCount = readUint16(6);
         entry.m_hotSpot = IntPoint();
     }
+    entry.m_byteSize = readUint32(8);
     entry.m_imageOffset = readUint32(12);
 
     // Some icons don't have a bit depth, only a color count.  Convert the
     // color count to the minimum necessary bit depth.  It doesn't matter if
     // this isn't quite what the bitmap info header says later, as we only use
     // this value to determine which icon entry is best.
     if (!entry.m_bitCount) {
         int colorCount = readUint8(2);
         if (!colorCount)
             colorCount = 256;  // Vague in the spec, needed by real-world icons.
@@ skipping 12 matching lines @@
     ASSERT_WITH_SECURITY_IMPLICATION(index < m_dirEntries.size());
     const uint32_t imageOffset = m_dirEntries[index].m_imageOffset;
     if ((imageOffset > m_data->size()) || ((m_data->size() - imageOffset) < 4))
         return Unknown;
     char buffer[4];
     const char* data = m_fastReader.getConsecutiveData(imageOffset, 4, buffer);
     return strncmp(data, "\x89PNG", 4) ? BMP : PNG;
 }
 
 } // namespace blink