Revert of Delete SkImageDecoder

src/ports/SkImageDecoder_WIC.cpp

Index: src/ports/SkImageDecoder_WIC.cpp
diff --git a/src/ports/SkImageDecoder_WIC.cpp b/src/ports/SkImageDecoder_WIC.cpp
index ef6de00dc93335bbbb967711eb53cc0f02fb729d..c7222e635a993f97f5e07ee0bc140f64b1864f5b 100644
--- a/src/ports/SkImageDecoder_WIC.cpp
+++ b/src/ports/SkImageDecoder_WIC.cpp
@@ -31,6 +31,7 @@
 
 #include <wincodec.h>
 #include "SkAutoCoInitialize.h"
+#include "SkImageDecoder.h"
 #include "SkImageEncoder.h"
 #include "SkIStream.h"
 #include "SkMovie.h"
@@ -47,6 +48,222 @@
 #undef CLSID_WICImagingFactory
 #endif
 
+class SkImageDecoder_WIC : public SkImageDecoder {
+public:
+    // Decoding modes corresponding to SkImageDecoder::Mode, plus an extra mode for decoding
+    // only the format.
+    enum WICModes {
+        kDecodeFormat_WICMode,
+        kDecodeBounds_WICMode,
+        kDecodePixels_WICMode,
+    };
+
+    /**
+     *  Helper function to decode an SkStream.
+     *  @param stream SkStream to decode. Must be at the beginning.
+     *  @param bm   SkBitmap to decode into. Only used if wicMode is kDecodeBounds_WICMode or
+     *      kDecodePixels_WICMode, in which case it must not be nullptr.
+     *  @param format Out parameter for the SkImageDecoder::Format of the SkStream. Only used if
+     *      wicMode is kDecodeFormat_WICMode.
+     */
+    bool decodeStream(SkStream* stream, SkBitmap* bm, WICModes wicMode, Format* format) const;
+
+protected:
+    Result onDecode(SkStream* stream, SkBitmap* bm, Mode mode) override;
+};
+
+struct FormatConversion {
+    GUID                    fGuidFormat;
+    SkImageDecoder::Format  fFormat;
+};
+
+static const FormatConversion gFormatConversions[] = {
+    { GUID_ContainerFormatBmp, SkImageDecoder::kBMP_Format },
+    { GUID_ContainerFormatGif, SkImageDecoder::kGIF_Format },
+    { GUID_ContainerFormatIco, SkImageDecoder::kICO_Format },
+    { GUID_ContainerFormatJpeg, SkImageDecoder::kJPEG_Format },
+    { GUID_ContainerFormatPng, SkImageDecoder::kPNG_Format },
+};
+
+static SkImageDecoder::Format GuidContainerFormat_to_Format(REFGUID guid) {
+    for (size_t i = 0; i < SK_ARRAY_COUNT(gFormatConversions); i++) {
+        if (IsEqualGUID(guid, gFormatConversions[i].fGuidFormat)) {
+            return gFormatConversions[i].fFormat;
+        }
+    }
+    return SkImageDecoder::kUnknown_Format;
+}
+
+SkImageDecoder::Result SkImageDecoder_WIC::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) {
+    WICModes wicMode;
+    switch (mode) {
+        case SkImageDecoder::kDecodeBounds_Mode:
+            wicMode = kDecodeBounds_WICMode;
+            break;
+        case SkImageDecoder::kDecodePixels_Mode:
+            wicMode = kDecodePixels_WICMode;
+            break;
+    }
+    return this->decodeStream(stream, bm, wicMode, nullptr) ? kSuccess : kFailure;
+}
+
+bool SkImageDecoder_WIC::decodeStream(SkStream* stream, SkBitmap* bm, WICModes wicMode,
+                                      Format* format) const {
+    //Initialize COM.
+    SkAutoCoInitialize scopedCo;
+    if (!scopedCo.succeeded()) {
+        return false;
+    }
+
+    HRESULT hr = S_OK;
+
+    //Create Windows Imaging Component ImagingFactory.
+    SkTScopedComPtr<IWICImagingFactory> piImagingFactory;
+    if (SUCCEEDED(hr)) {
+        hr = CoCreateInstance(
+            CLSID_WICImagingFactory
+            , nullptr
+            , CLSCTX_INPROC_SERVER
+            , IID_PPV_ARGS(&piImagingFactory)
+        );
+    }
+
+    //Convert SkStream to IStream.
+    SkTScopedComPtr<IStream> piStream;
+    if (SUCCEEDED(hr)) {
+        hr = SkIStream::CreateFromSkStream(stream, false, &piStream);
+    }
+
+    //Make sure we're at the beginning of the stream.
+    if (SUCCEEDED(hr)) {
+        LARGE_INTEGER liBeginning = { 0 };
+        hr = piStream->Seek(liBeginning, STREAM_SEEK_SET, nullptr);
+    }
+
+    //Create the decoder from the stream content.
+    SkTScopedComPtr<IWICBitmapDecoder> piBitmapDecoder;
+    if (SUCCEEDED(hr)) {
+        hr = piImagingFactory->CreateDecoderFromStream(
+            piStream.get()                    //Image to be decoded
+            , nullptr                            //No particular vendor
+            , WICDecodeMetadataCacheOnDemand  //Cache metadata when needed
+            , &piBitmapDecoder                //Pointer to the decoder
+        );
+    }
+
+    if (kDecodeFormat_WICMode == wicMode) {
+        SkASSERT(format != nullptr);
+        //Get the format
+        if (SUCCEEDED(hr)) {
+            GUID guidFormat;
+            hr = piBitmapDecoder->GetContainerFormat(&guidFormat);
+            if (SUCCEEDED(hr)) {
+                *format = GuidContainerFormat_to_Format(guidFormat);
+                return true;
+            }
+        }
+        return false;
+    }
+
+    //Get the first frame from the decoder.
+    SkTScopedComPtr<IWICBitmapFrameDecode> piBitmapFrameDecode;
+    if (SUCCEEDED(hr)) {
+        hr = piBitmapDecoder->GetFrame(0, &piBitmapFrameDecode);
+    }
+
+    //Get the BitmapSource interface of the frame.
+    SkTScopedComPtr<IWICBitmapSource> piBitmapSourceOriginal;
+    if (SUCCEEDED(hr)) {
+        hr = piBitmapFrameDecode->QueryInterface(
+            IID_PPV_ARGS(&piBitmapSourceOriginal)
+        );
+    }
+
+    //Get the size of the bitmap.
+    UINT width;
+    UINT height;
+    if (SUCCEEDED(hr)) {
+        hr = piBitmapSourceOriginal->GetSize(&width, &height);
+    }
+
+    //Exit early if we're only looking for the bitmap bounds.
+    if (SUCCEEDED(hr)) {
+        bm->setInfo(SkImageInfo::MakeN32Premul(width, height));
+        if (kDecodeBounds_WICMode == wicMode) {
+            return true;
+        }
+        if (!this->allocPixelRef(bm, nullptr)) {
+            return false;
+        }
+    }
+
+    //Create a format converter.
+    SkTScopedComPtr<IWICFormatConverter> piFormatConverter;
+    if (SUCCEEDED(hr)) {
+        hr = piImagingFactory->CreateFormatConverter(&piFormatConverter);
+    }
+
+    GUID destinationPixelFormat;
+    if (this->getRequireUnpremultipliedColors()) {
+        destinationPixelFormat = GUID_WICPixelFormat32bppBGRA;
+    } else {
+        destinationPixelFormat = GUID_WICPixelFormat32bppPBGRA;
+    }
+
+    if (SUCCEEDED(hr)) {
+        hr = piFormatConverter->Initialize(
+            piBitmapSourceOriginal.get()      //Input bitmap to convert
+            , destinationPixelFormat          //Destination pixel format
+            , WICBitmapDitherTypeNone         //Specified dither patterm
+            , nullptr                            //Specify a particular palette
+            , 0.f                             //Alpha threshold
+            , WICBitmapPaletteTypeCustom      //Palette translation type
+        );
+    }
+
+    //Get the BitmapSource interface of the format converter.
+    SkTScopedComPtr<IWICBitmapSource> piBitmapSourceConverted;
+    if (SUCCEEDED(hr)) {
+        hr = piFormatConverter->QueryInterface(
+            IID_PPV_ARGS(&piBitmapSourceConverted)
+        );
+    }
+
+    //Copy the pixels into the bitmap.
+    if (SUCCEEDED(hr)) {
+        SkAutoLockPixels alp(*bm);
+        bm->eraseColor(SK_ColorTRANSPARENT);
+        const UINT stride = (UINT) bm->rowBytes();
+        hr = piBitmapSourceConverted->CopyPixels(
+            nullptr,                             //Get all the pixels
+            stride,
+            stride * height,
+            reinterpret_cast<BYTE *>(bm->getPixels())
+        );
+
+        // Note: we don't need to premultiply here since we specified PBGRA
+        if (SkBitmap::ComputeIsOpaque(*bm)) {
+            bm->setAlphaType(kOpaque_SkAlphaType);
+        }
+    }
+
+    return SUCCEEDED(hr);
+}
+
+/////////////////////////////////////////////////////////////////////////
+
+extern SkImageDecoder* image_decoder_from_stream(SkStreamRewindable*);
+
+SkImageDecoder* SkImageDecoder::Factory(SkStreamRewindable* stream) {
+    SkImageDecoder* decoder = image_decoder_from_stream(stream);
+    if (nullptr == decoder) {
+        // If no image decoder specific to the stream exists, use SkImageDecoder_WIC.
+        return new SkImageDecoder_WIC;
+    } else {
+        return decoder;
+    }
+}
+
 /////////////////////////////////////////////////////////////////////////
 
 SkMovie* SkMovie::DecodeStream(SkStreamRewindable* stream) {
@@ -58,10 +275,6 @@
 class SkImageEncoder_WIC : public SkImageEncoder {
 public:
     SkImageEncoder_WIC(Type t) : fType(t) {}
-    
-    // DO NOT USE this constructor.  This exists only so SkForceLinking can
-    // link the WIC image encoder.
-    SkImageEncoder_WIC() {}
 
 protected:
     virtual bool onEncode(SkWStream* stream, const SkBitmap& bm, int quality);
@@ -238,6 +451,15 @@
 
 static SkImageEncoder_EncodeReg gEReg(sk_imageencoder_wic_factory);
 
-DEFINE_ENCODER_CREATOR(ImageEncoder_WIC);
+static SkImageDecoder::Format get_format_wic(SkStreamRewindable* stream) {
+    SkImageDecoder::Format format;
+    SkImageDecoder_WIC codec;
+    if (!codec.decodeStream(stream, nullptr, SkImageDecoder_WIC::kDecodeFormat_WICMode, &format)) {
+        format = SkImageDecoder::kUnknown_Format;
+    }
+    return format;
+}
+
+static SkImageDecoder_FormatReg gFormatReg(get_format_wic);
 
 #endif // defined(SK_BUILD_FOR_WIN32)