Refactor ImageDecoder factories

third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h

Index: third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h
diff --git a/third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h b/third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h
index a44d261b49b45e02fd25415aa1f76c59c2551f42..bedc7d3d1dc3340b946e47a87de11feb6b94a65c 100644
--- a/third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h
+++ b/third_party/WebKit/Source/platform/image-decoders/ImageDecoder.h
@@ -94,38 +94,29 @@ public:
         GammaAndColorProfileIgnored
     };
 
-    enum class SniffResult {
-        JPEG,
-        PNG,
-        GIF,
-        WEBP,
-        ICO,
-        BMP,
-        InsufficientData,
-        Invalid
-    };
-
-    static SniffResult determineImageType(const char* data, size_t length);
-    static SniffResult determineImageType(const SharedBuffer&);
-    static SniffResult determineImageType(const SegmentReader&);
-
-    ImageDecoder(AlphaOption alphaOption, GammaAndColorProfileOption colorOptions, size_t maxDecodedBytes)
-        : m_premultiplyAlpha(alphaOption == AlphaPremultiplied)
-        , m_ignoreGammaAndColorProfile(colorOptions == GammaAndColorProfileIgnored)
-        , m_maxDecodedBytes(maxDecodedBytes) { }
-
     virtual ~ImageDecoder() { }
 
-    // Returns a caller-owned decoder of the appropriate type.  Returns 0 if
+    // Returns a caller-owned decoder of the appropriate type.  Returns nullptr if
     // we can't sniff a supported type from the provided data (possibly
     // because there isn't enough data yet).
     // Sets m_maxDecodedBytes to Platform::maxImageDecodedBytes().
-    static std::unique_ptr<ImageDecoder> create(SniffResult, AlphaOption, GammaAndColorProfileOption);
+    static std::unique_ptr<ImageDecoder> create(PassRefPtr<SegmentReader> data, bool dataComplete,
+        AlphaOption, GammaAndColorProfileOption);
+    static std::unique_ptr<ImageDecoder> create(PassRefPtr<SharedBuffer> data, bool dataComplete,
+        AlphaOption alphaoption, GammaAndColorProfileOption colorOptions)
+    {
+        return create(SegmentReader::createFromSharedBuffer(data), dataComplete, alphaoption, colorOptions);
+    }
+
 
     virtual String filenameExtension() const = 0;
 
     bool isAllDataReceived() const { return m_isAllDataReceived; }
 
+    // Returns true if the buffer holds enough data to instantiate a decoder. This is useful for
+    // callers to determine whether a decoder instantiation failure is due to insufficient or bad data.

[Peter Kasting, 2016/08/19 23:04:58]

Nit: Seems like most of this file prefers to wrap comments at 80 cols.

[f(malita), 2016/08/22 01:51:16]

Done.

+    static bool isSufficientData(const SharedBuffer&);

[Peter Kasting, 2016/08/19 23:04:58]

Nit: I'm not a big fan of this function name.  Something like
hasSufficientDataToSniffImageType() or canSniffImageType() might be better. 
(The latter reads more clearly but I'm worried it implies we should return false
if the sniffed type is invalid.)

[f(malita), 2016/08/22 01:51:16]

Changed to hasSufficientDataToSniffImageType().

+
     void setData(PassRefPtr<SegmentReader> data, bool allDataReceived)
     {
         if (m_failed)
@@ -282,6 +273,11 @@ public:
     virtual void setImagePlanes(std::unique_ptr<ImagePlanes>) { }
 
 protected:
+    ImageDecoder(AlphaOption alphaOption, GammaAndColorProfileOption colorOptions, size_t maxDecodedBytes)
+        : m_premultiplyAlpha(alphaOption == AlphaPremultiplied)
+        , m_ignoreGammaAndColorProfile(colorOptions == GammaAndColorProfileIgnored)
+        , m_maxDecodedBytes(maxDecodedBytes) { }
+
     // Calculates the most recent frame whose image data may be needed in
     // order to decode frame |frameIndex|, based on frame disposal methods
     // and |frameRectIsOpaque|, where |frameRectIsOpaque| signifies whether
@@ -334,6 +330,18 @@ protected:
     const size_t m_maxDecodedBytes;
 
 private:
+    enum class SniffResult {
+        JPEG,
+        PNG,
+        GIF,
+        WEBP,
+        ICO,
+        BMP,
+        Invalid
+    };
+
+    static SniffResult determineImageType(const char* data, size_t length);
+
     // Some code paths compute the size of the image as "width * height * 4"
     // and return it as a (signed) int.  Avoid overflow.
     static bool sizeCalculationMayOverflow(unsigned width, unsigned height)