Merge 125869 - Source/WebCore: libwebp-0.2.0: handle alpha channel if present

Source/WebCore/platform/image-decoders/webp/WEBPImageDecoder.cpp

 /*
  * Copyright (C) 2010 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:
  *
  * 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
@@ skipping 19 matching lines @@
 #include "WEBPImageDecoder.h"
 
 #if USE(WEBP)
 
 #include "webp/decode.h"
 
 #if PLATFORM(CHROMIUM)
 #include "TraceEvent.h"
 #endif
 
+// backward emulation for earlier versions than 0.1.99
+#if (WEBP_DECODER_ABI_VERSION < 0x0163)
+#define MODE_rgbA MODE_RGBA
+#define MODE_bgrA MODE_BGRA
+#endif
+
 #if CPU(BIG_ENDIAN) || CPU(MIDDLE_ENDIAN)
-inline WEBP_CSP_MODE outputMode() { return MODE_RGBA; }
+inline WEBP_CSP_MODE outputMode(bool hasAlpha) { return hasAlpha ? MODE_rgbA : MODE_RGBA; }
 #elif USE(SKIA) && SK_B32_SHIFT
-inline WEBP_CSP_MODE outputMode() { return MODE_RGBA; }
+inline WEBP_CSP_MODE outputMode(bool hasAlpha) { return hasAlpha ? MODE_rgbA : MODE_RGBA; }
 #else // LITTLE_ENDIAN, output BGRA pixels.
-inline WEBP_CSP_MODE outputMode() { return MODE_BGRA; }
+inline WEBP_CSP_MODE outputMode(bool hasAlpha) { return hasAlpha ? MODE_bgrA : MODE_BGRA; }
 #endif
 
 namespace WebCore {
 
 WEBPImageDecoder::WEBPImageDecoder(ImageSource::AlphaOption alphaOption,
                                    ImageSource::GammaAndColorProfileOption gammaAndColorProfileOption)
     : ImageDecoder(alphaOption, gammaAndColorProfileOption)
     , m_decoder(0)
+    , m_hasAlpha(false)
 {
 }
 
 WEBPImageDecoder::~WEBPImageDecoder()
 {
     if (m_decoder)
         WebPIDelete(m_decoder);
     m_decoder = 0;
 }
 
@@ skipping 30 matching lines @@
         return false;
 
     const uint8_t* dataBytes = reinterpret_cast<const uint8_t*>(m_data->data());
     const size_t dataSize = m_data->size();
 
     if (!ImageDecoder::isSizeAvailable()) {
         static const size_t imageHeaderSize = 30;
         if (dataSize < imageHeaderSize)
             return false;
         int width, height;
+#if (WEBP_DECODER_ABI_VERSION >= 0x0163)
+        WebPBitstreamFeatures features;
+        if (WebPGetFeatures(dataBytes, dataSize, &features) != VP8_STATUS_OK)
+            return setFailed();
+        width = features.width;
+        height = features.height;
+        m_hasAlpha = features.has_alpha;
+#else
+        // Earlier version won't be able to display WebP files with alpha.
         if (!WebPGetInfo(dataBytes, dataSize, &width, &height))
             return setFailed();
+        m_hasAlpha = false;
+#endif
         if (!setSize(width, height))
             return setFailed();
     }
 
     ASSERT(ImageDecoder::isSizeAvailable());
     if (onlySize)
         return true;
 
     ASSERT(!m_frameBufferCache.isEmpty());
     ImageFrame& buffer = m_frameBufferCache[0];
     ASSERT(buffer.status() != ImageFrame::FrameComplete);
 
     if (buffer.status() == ImageFrame::FrameEmpty) {
         if (!buffer.setSize(size().width(), size().height()))
             return setFailed();
         buffer.setStatus(ImageFrame::FramePartial);
-        buffer.setHasAlpha(false); // FIXME: webp does not support alpha yet.
+        buffer.setHasAlpha(m_hasAlpha);
         buffer.setOriginalFrameRect(IntRect(IntPoint(), size()));
     }
 
     if (!m_decoder) {
         int rowStride = size().width() * sizeof(ImageFrame::PixelData);
         uint8_t* output = reinterpret_cast<uint8_t*>(buffer.getAddr(0, 0));
         int outputSize = size().height() * rowStride;
-        m_decoder = WebPINewRGB(outputMode(), output, outputSize, rowStride);
+        m_decoder = WebPINewRGB(outputMode(m_hasAlpha), output, outputSize, rowStride);
         if (!m_decoder)
             return setFailed();
     }
 
     switch (WebPIUpdate(m_decoder, dataBytes, dataSize)) {
     case VP8_STATUS_OK:
         buffer.setStatus(ImageFrame::FrameComplete);
         WebPIDelete(m_decoder);
         m_decoder = 0;
         return true;
     case VP8_STATUS_SUSPENDED:
         return false;
     default:
         WebPIDelete(m_decoder);
         m_decoder = 0;
         return setFailed();
     }
 }
 
 } // namespace WebCore
 
 #endif