Revert of Delete SkImageDecoder

src/ports/SkImageDecoder_CG.cpp

Index: src/ports/SkImageDecoder_CG.cpp
diff --git a/src/ports/SkImageDecoder_CG.cpp b/src/ports/SkImageDecoder_CG.cpp
index 6673c240efcd0f03b811e789c5ffb31dbbb09ec7..c4446ae16d67ef5671c817af569f188a73fe177d 100644
--- a/src/ports/SkImageDecoder_CG.cpp
+++ b/src/ports/SkImageDecoder_CG.cpp
@@ -11,6 +11,7 @@
 #include "SkCGUtils.h"
 #include "SkColorPriv.h"
 #include "SkData.h"
+#include "SkImageDecoder.h"
 #include "SkImageEncoder.h"
 #include "SkMovie.h"
 #include "SkStream.h"
@@ -27,6 +28,210 @@
 #include <ImageIO/ImageIO.h>
 #include <MobileCoreServices/MobileCoreServices.h>
 #endif
+
+static void data_unref_proc(void* skdata, const void*, size_t) {
+    SkASSERT(skdata);
+    static_cast<SkData*>(skdata)->unref();
+}
+
+static CGDataProviderRef SkStreamToDataProvider(SkStream* stream) {
+    // TODO: use callbacks, so we don't have to load all the data into RAM
+    SkData* skdata = SkCopyStreamToData(stream).release();
+    if (!skdata) {
+        return nullptr;
+    }
+
+    return CGDataProviderCreateWithData(skdata, skdata->data(), skdata->size(), data_unref_proc);
+}
+
+static CGImageSourceRef SkStreamToCGImageSource(SkStream* stream) {
+    CGDataProviderRef data = SkStreamToDataProvider(stream);
+    if (!data) {
+        return nullptr;
+    }
+    CGImageSourceRef imageSrc = CGImageSourceCreateWithDataProvider(data, 0);
+    CGDataProviderRelease(data);
+    return imageSrc;
+}
+
+class SkImageDecoder_CG : public SkImageDecoder {
+protected:
+    virtual Result onDecode(SkStream* stream, SkBitmap* bm, Mode);
+};
+
+static void argb_4444_force_opaque(void* row, int count) {
+    uint16_t* row16 = (uint16_t*)row;
+    for (int i = 0; i < count; ++i) {
+        row16[i] |= 0xF000;
+    }
+}
+
+static void argb_8888_force_opaque(void* row, int count) {
+    // can use RGBA or BGRA, they have the same shift for alpha
+    const uint32_t alphaMask = 0xFF << SK_RGBA_A32_SHIFT;
+    uint32_t* row32 = (uint32_t*)row;
+    for (int i = 0; i < count; ++i) {
+        row32[i] |= alphaMask;
+    }
+}
+
+static void alpha_8_force_opaque(void* row, int count) {
+    memset(row, 0xFF, count);
+}
+
+static void force_opaque(SkBitmap* bm) {
+    SkAutoLockPixels alp(*bm);
+    if (!bm->getPixels()) {
+        return;
+    }
+
+    void (*proc)(void*, int);
+    switch (bm->colorType()) {
+        case kARGB_4444_SkColorType:
+            proc = argb_4444_force_opaque;
+            break;
+        case kRGBA_8888_SkColorType:
+        case kBGRA_8888_SkColorType:
+            proc = argb_8888_force_opaque;
+            break;
+        case kAlpha_8_SkColorType:
+            proc = alpha_8_force_opaque;
+            break;
+        default:
+            return;
+    }
+
+    char* row = (char*)bm->getPixels();
+    for (int y = 0; y < bm->height(); ++y) {
+        proc(row, bm->width());
+        row += bm->rowBytes();
+    }
+    bm->setAlphaType(kOpaque_SkAlphaType);
+}
+
+#define BITMAP_INFO (kCGBitmapByteOrder32Big | kCGImageAlphaPremultipliedLast)
+
+class AutoCFDataRelease {
+    CFDataRef fDR;
+public:
+    AutoCFDataRelease(CFDataRef dr) : fDR(dr) {}
+    ~AutoCFDataRelease() { if (fDR) { CFRelease(fDR); } }
+
+    operator CFDataRef () { return fDR; }
+};
+
+static bool colorspace_is_sRGB(CGColorSpaceRef cs) {
+#ifdef SK_BUILD_FOR_IOS
+    return true;    // iOS seems to define itself to always return sRGB <reed>
+#else
+    AutoCFDataRelease data(CGColorSpaceCopyICCProfile(cs));
+    if (data) {
+        // found by inspection -- need a cleaner way to sniff a profile
+        const CFIndex ICC_PROFILE_OFFSET_TO_SRGB_TAG = 52;
+
+        if (CFDataGetLength(data) >= ICC_PROFILE_OFFSET_TO_SRGB_TAG + 4) {
+            return !memcmp(CFDataGetBytePtr(data) + ICC_PROFILE_OFFSET_TO_SRGB_TAG, "sRGB", 4);
+        }
+    }
+    return false;
+#endif
+}
+
+SkImageDecoder::Result SkImageDecoder_CG::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) {
+    CGImageSourceRef imageSrc = SkStreamToCGImageSource(stream);
+
+    if (nullptr == imageSrc) {
+        return kFailure;
+    }
+    SkAutoTCallVProc<const void, CFRelease> arsrc(imageSrc);
+
+    CGImageRef image = CGImageSourceCreateImageAtIndex(imageSrc, 0, nullptr);
+    if (nullptr == image) {
+        return kFailure;
+    }
+    SkAutoTCallVProc<CGImage, CGImageRelease> arimage(image);
+
+    const int width = SkToInt(CGImageGetWidth(image));
+    const int height = SkToInt(CGImageGetHeight(image));
+    SkColorProfileType cpType = kLinear_SkColorProfileType;
+
+    CGColorSpaceRef cs = CGImageGetColorSpace(image);
+    if (cs) {
+        CGColorSpaceModel m = CGColorSpaceGetModel(cs);
+        if (kCGColorSpaceModelRGB == m && colorspace_is_sRGB(cs)) {
+            cpType = kSRGB_SkColorProfileType;
+        }
+    }
+
+    SkAlphaType at = kPremul_SkAlphaType;
+    switch (CGImageGetAlphaInfo(image)) {
+        case kCGImageAlphaNone:
+        case kCGImageAlphaNoneSkipLast:
+        case kCGImageAlphaNoneSkipFirst:
+            at = kOpaque_SkAlphaType;
+            break;
+        default:
+            break;
+    }
+
+    bm->setInfo(SkImageInfo::Make(width, height, kN32_SkColorType, at, cpType));
+    if (SkImageDecoder::kDecodeBounds_Mode == mode) {
+        return kSuccess;
+    }
+
+    if (!this->allocPixelRef(bm, nullptr)) {
+        return kFailure;
+    }
+
+    SkAutoLockPixels alp(*bm);
+
+    if (!SkCopyPixelsFromCGImage(bm->info(), bm->rowBytes(), bm->getPixels(), image)) {
+        return kFailure;
+    }
+
+    CGImageAlphaInfo info = CGImageGetAlphaInfo(image);
+    switch (info) {
+        case kCGImageAlphaNone:
+        case kCGImageAlphaNoneSkipLast:
+        case kCGImageAlphaNoneSkipFirst:
+            // We're opaque, but we can't rely on the data always having 0xFF
+            // in the alpha slot (which Skia wants), so we have to ram it in
+            // ourselves.
+            force_opaque(bm);
+            break;
+        default:
+            // we don't know if we're opaque or not, so compute it.
+            if (SkBitmap::ComputeIsOpaque(*bm)) {
+                bm->setAlphaType(kOpaque_SkAlphaType);
+            }
+    }
+    if (!bm->isOpaque() && this->getRequireUnpremultipliedColors()) {
+        // CGBitmapContext does not support unpremultiplied, so the image has been premultiplied.
+        // Convert to unpremultiplied.
+        for (int i = 0; i < width; ++i) {
+            for (int j = 0; j < height; ++j) {
+                uint32_t* addr = bm->getAddr32(i, j);
+                *addr = SkUnPreMultiply::UnPreMultiplyPreservingByteOrder(*addr);
+            }
+        }
+        bm->setAlphaType(kUnpremul_SkAlphaType);
+    }
+    return kSuccess;
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+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_CG.
+        return new SkImageDecoder_CG;
+    } else {
+        return decoder;
+    }
+}
 
 /////////////////////////////////////////////////////////////////////////
 
@@ -161,4 +366,46 @@
 DEFINE_ENCODER_CREATOR(PNGImageEncoder_IOS);
 #endif
 
+struct FormatConversion {
+    CFStringRef             fUTType;
+    SkImageDecoder::Format  fFormat;
+};
+
+// Array of the types supported by the decoder.
+static const FormatConversion gFormatConversions[] = {
+    { kUTTypeBMP, SkImageDecoder::kBMP_Format },
+    { kUTTypeGIF, SkImageDecoder::kGIF_Format },
+    { kUTTypeICO, SkImageDecoder::kICO_Format },
+    { kUTTypeJPEG, SkImageDecoder::kJPEG_Format },
+    // Also include JPEG2000
+    { kUTTypeJPEG2000, SkImageDecoder::kJPEG_Format },
+    { kUTTypePNG, SkImageDecoder::kPNG_Format },
+};
+
+static SkImageDecoder::Format UTType_to_Format(const CFStringRef uttype) {
+    for (size_t i = 0; i < SK_ARRAY_COUNT(gFormatConversions); i++) {
+        if (CFStringCompare(uttype, gFormatConversions[i].fUTType, 0) == kCFCompareEqualTo) {
+            return gFormatConversions[i].fFormat;
+        }
+    }
+    return SkImageDecoder::kUnknown_Format;
+}
+
+static SkImageDecoder::Format get_format_cg(SkStreamRewindable* stream) {
+    CGImageSourceRef imageSrc = SkStreamToCGImageSource(stream);
+
+    if (nullptr == imageSrc) {
+        return SkImageDecoder::kUnknown_Format;
+    }
+
+    SkAutoTCallVProc<const void, CFRelease> arsrc(imageSrc);
+    const CFStringRef name = CGImageSourceGetType(imageSrc);
+    if (nullptr == name) {
+        return SkImageDecoder::kUnknown_Format;
+    }
+    return UTType_to_Format(name);
+}
+
+static SkImageDecoder_FormatReg gFormatReg(get_format_cg);
+
 #endif//defined(SK_BUILD_FOR_MAC) || defined(SK_BUILD_FOR_IOS)