Add getYUV8Planes() API to SkCodec

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1549473003

Review URL: https://codereview.chromium.org/1549473003

4 files changed, 262 insertions, 2 deletions

diff --git a/src/codec/SkCodecImageGenerator.cpp b/src/codec/SkCodecImageGenerator.cpp
index 2fef381ec1..e6e164ef61 100644
--- a/src/codec/SkCodecImageGenerator.cpp
+++ b/src/codec/SkCodecImageGenerator.cpp
@@ -16,10 +16,21 @@ SkImageGenerator* SkCodecImageGenerator::NewFromEncodedCodec(SkData* data) {
     return new SkCodecImageGenerator(codec, data);
 }
 
+static SkImageInfo make_premul(const SkImageInfo& info) {
+    if (kUnpremul_SkAlphaType == info.alphaType()) {
+        return info.makeAlphaType(kPremul_SkAlphaType);
+    }
+
+    return info;
+}
+
 SkCodecImageGenerator::SkCodecImageGenerator(SkCodec* codec, SkData* data)
-    : INHERITED(codec->getInfo())
+    : INHERITED(make_premul(codec->getInfo()))
     , fCodec(codec)
     , fData(SkRef(data))
+    , fYWidth(0)
+    , fUWidth(0)
+    , fVWidth(0)
 {}
 
 SkData* SkCodecImageGenerator::onRefEncodedData(SK_REFENCODEDDATA_CTXPARAM) {
@@ -42,5 +53,51 @@ bool SkCodecImageGenerator::onGetPixels(const SkImageInfo& info, void* pixels, s
 
 bool SkCodecImageGenerator::onGetYUV8Planes(SkISize sizes[3], void* planes[3], size_t rowBytes[3],
         SkYUVColorSpace* colorSpace) {
-    return false;
+    // TODO (msarett): Change the YUV API in ImageGenerator to match SkCodec.
+    //                 This function is currently a hack to match the implementation
+    //                 in SkCodec with the old API.
+    SkCodec::YUVSizeInfo sizeInfo;
+
+    // If planes is NULL, we just need to return the size.
+    if (nullptr == planes) {
+        bool result = fCodec->queryYUV8(&sizeInfo, colorSpace);
+        if (result) {
+            // Save the true widths
+            fYWidth = sizeInfo.fYSize.width();
+            fUWidth = sizeInfo.fUSize.width();
+            fVWidth = sizeInfo.fVSize.width();
+
+            // Set the sizes so that the client allocates enough memory
+            sizes[0].fWidth = (int) sizeInfo.fYWidthBytes;
+            sizes[0].fHeight = sizeInfo.fYSize.height();
+            sizes[1].fWidth = (int) sizeInfo.fUWidthBytes;
+            sizes[1].fHeight = sizeInfo.fUSize.height();
+            sizes[2].fWidth = (int) sizeInfo.fVWidthBytes;
+            sizes[2].fHeight = sizeInfo.fVSize.height();
+        }
+        return result;
+    }
+
+    // Set the sizeInfo with the true widths and heights
+    SkASSERT(fYWidth != 0 && fUWidth != 0 && fVWidth != 0);
+    sizeInfo.fYSize.set(fYWidth, sizes[0].height());
+    sizeInfo.fUSize.set(fUWidth, sizes[1].height());
+    sizeInfo.fVSize.set(fVWidth, sizes[2].height());
+
+    // Set the sizeInfo with the allocated widths
+    sizeInfo.fYWidthBytes = sizes[0].width();
+    sizeInfo.fUWidthBytes = sizes[1].width();
+    sizeInfo.fVWidthBytes = sizes[2].width();
+    SkCodec::Result result = fCodec->getYUV8Planes(sizeInfo, planes);
+    if ((result == SkCodec::kSuccess || result == SkCodec::kIncompleteInput) && colorSpace) {
+        *colorSpace = kJPEG_SkYUVColorSpace;
+    }
+
+    switch (result) {
+        case SkCodec::kSuccess:
+        case SkCodec::kIncompleteInput:
+            return true;
+        default:
+            return false;
+    }
 }
diff --git a/src/codec/SkCodecImageGenerator.h b/src/codec/SkCodecImageGenerator.h
index 80eacb19c8..d2c74ab482 100644
--- a/src/codec/SkCodecImageGenerator.h
+++ b/src/codec/SkCodecImageGenerator.h
@@ -39,5 +39,11 @@ private:
     SkAutoTDelete<SkCodec> fCodec;
     SkAutoTUnref<SkData> fData;
 
+    // FIXME: These fields are necessary only until we change the API of SkImageGenerator
+    //        to match SkCodec.  Once the API is changed, they should be removed.
+    int fYWidth;
+    int fUWidth;
+    int fVWidth;
+
     typedef SkImageGenerator INHERITED;
 };
diff --git a/src/codec/SkJpegCodec.cpp b/src/codec/SkJpegCodec.cpp
index 89925fb464..50db897a8e 100644
--- a/src/codec/SkJpegCodec.cpp
+++ b/src/codec/SkJpegCodec.cpp
@@ -451,3 +451,196 @@ bool SkJpegCodec::onSkipScanlines(int count) {
 
     return (uint32_t) count == jpeg_skip_scanlines(fDecoderMgr->dinfo(), count);
 }
+
+static bool is_yuv_supported(jpeg_decompress_struct* dinfo) {
+    // Scaling is not supported in raw data mode.
+    SkASSERT(dinfo->scale_num == dinfo->scale_denom);
+
+    // I can't imagine that this would ever change, but we do depend on it.
+    static_assert(8 == DCTSIZE, "DCTSIZE (defined in jpeg library) should always be 8.");
+
+    if (JCS_YCbCr != dinfo->jpeg_color_space) {
+        return false;
+    }
+
+    SkASSERT(3 == dinfo->num_components);
+    SkASSERT(dinfo->comp_info);
+
+    // It is possible to perform a YUV decode for any combination of
+    // horizontal and vertical sampling that is supported by
+    // libjpeg/libjpeg-turbo.  However, we will start by supporting only the
+    // common cases (where U and V have samp_factors of one).
+    //
+    // The definition of samp_factor is kind of the opposite of what SkCodec
+    // thinks of as a sampling factor.  samp_factor is essentially a
+    // multiplier, and the larger the samp_factor is, the more samples that
+    // there will be.  Ex:
+    //     U_plane_width = image_width * (U_h_samp_factor / max_h_samp_factor)
+    //
+    // Supporting cases where the samp_factors for U or V were larger than
+    // that of Y would be an extremely difficult change, given that clients
+    // allocate memory as if the size of the Y plane is always the size of the
+    // image.  However, this case is very, very rare.
+    if (!(1 == dinfo->comp_info[1].h_samp_factor) &&
+         (1 == dinfo->comp_info[1].v_samp_factor) &&
+         (1 == dinfo->comp_info[2].h_samp_factor) &&
+         (1 == dinfo->comp_info[2].v_samp_factor)) {
+        return false;
+    }
+
+    // Support all common cases of Y samp_factors.
+    // TODO (msarett): As mentioned above, it would be possible to support
+    //                 more combinations of samp_factors.  The issues are:
+    //                 (1) Are there actually any images that are not covered
+    //                     by these cases?
+    //                 (2) How much complexity would be added to the
+    //                     implementation in order to support these rare
+    //                     cases?
+    int hSampY = dinfo->comp_info[0].h_samp_factor;
+    int vSampY = dinfo->comp_info[0].v_samp_factor;
+    return (1 == hSampY && 1 == vSampY) ||
+           (2 == hSampY && 1 == vSampY) ||
+           (2 == hSampY && 2 == vSampY) ||
+           (1 == hSampY && 2 == vSampY) ||
+           (4 == hSampY && 1 == vSampY) ||
+           (4 == hSampY && 2 == vSampY);
+}
+
+bool SkJpegCodec::onQueryYUV8(YUVSizeInfo* sizeInfo, SkYUVColorSpace* colorSpace) const {
+    jpeg_decompress_struct* dinfo = fDecoderMgr->dinfo();
+    if (!is_yuv_supported(dinfo)) {
+        return false;
+    }
+
+    sizeInfo->fYSize.set(dinfo->comp_info[0].downsampled_width,
+                         dinfo->comp_info[0].downsampled_height);
+    sizeInfo->fUSize.set(dinfo->comp_info[1].downsampled_width,
+                         dinfo->comp_info[1].downsampled_height);
+    sizeInfo->fVSize.set(dinfo->comp_info[2].downsampled_width,
+                         dinfo->comp_info[2].downsampled_height);
+    sizeInfo->fYWidthBytes = dinfo->comp_info[0].width_in_blocks * DCTSIZE;
+    sizeInfo->fUWidthBytes = dinfo->comp_info[1].width_in_blocks * DCTSIZE;
+    sizeInfo->fVWidthBytes = dinfo->comp_info[2].width_in_blocks * DCTSIZE;
+
+    if (colorSpace) {
+        *colorSpace = kJPEG_SkYUVColorSpace;
+    }
+
+    return true;
+}
+
+SkCodec::Result SkJpegCodec::onGetYUV8Planes(const YUVSizeInfo& sizeInfo, void* pixels[3]) {
+    YUVSizeInfo defaultInfo;
+
+    // This will check is_yuv_supported(), so we don't need to here.
+    bool supportsYUV = this->onQueryYUV8(&defaultInfo, nullptr);
+    if (!supportsYUV || sizeInfo.fYSize != defaultInfo.fYSize ||
+            sizeInfo.fUSize != defaultInfo.fUSize ||
+            sizeInfo.fVSize != defaultInfo.fVSize ||
+            sizeInfo.fYWidthBytes < defaultInfo.fYWidthBytes ||
+            sizeInfo.fUWidthBytes < defaultInfo.fUWidthBytes ||
+            sizeInfo.fVWidthBytes < defaultInfo.fVWidthBytes) {
+        return fDecoderMgr->returnFailure("onGetYUV8Planes", kInvalidInput);
+    }
+
+    // Set the jump location for libjpeg errors
+    if (setjmp(fDecoderMgr->getJmpBuf())) {
+        return fDecoderMgr->returnFailure("setjmp", kInvalidInput);
+    }
+
+    // Get a pointer to the decompress info since we will use it quite frequently
+    jpeg_decompress_struct* dinfo = fDecoderMgr->dinfo();
+
+    dinfo->raw_data_out = TRUE;
+    if (!jpeg_start_decompress(dinfo)) {
+        return fDecoderMgr->returnFailure("startDecompress", kInvalidInput);
+    }
+
+    // A previous implementation claims that the return value of is_yuv_supported()
+    // may change after calling jpeg_start_decompress().  It looks to me like this
+    // was caused by a bug in the old code, but we'll be safe and check here.
+    SkASSERT(is_yuv_supported(dinfo));
+
+    // Currently, we require that the Y plane dimensions match the image dimensions
+    // and that the U and V planes are the same dimensions.
+    SkASSERT(sizeInfo.fUSize == sizeInfo.fVSize);
+    SkASSERT((uint32_t) sizeInfo.fYSize.width() == dinfo->output_width &&
+            (uint32_t) sizeInfo.fYSize.height() == dinfo->output_height);
+
+    // Build a JSAMPIMAGE to handle output from libjpeg-turbo.  A JSAMPIMAGE has
+    // a 2-D array of pixels for each of the components (Y, U, V) in the image.
+    // Cheat Sheet:
+    //     JSAMPIMAGE == JSAMPLEARRAY* == JSAMPROW** == JSAMPLE***
+    JSAMPARRAY yuv[3];
+
+    // Set aside enough space for pointers to rows of Y, U, and V.
+    JSAMPROW rowptrs[2 * DCTSIZE + DCTSIZE + DCTSIZE];
+    yuv[0] = &rowptrs[0];           // Y rows (DCTSIZE or 2 * DCTSIZE)
+    yuv[1] = &rowptrs[2 * DCTSIZE]; // U rows (DCTSIZE)
+    yuv[2] = &rowptrs[3 * DCTSIZE]; // V rows (DCTSIZE)
+
+    // Initialize rowptrs.
+    int numYRowsPerBlock = DCTSIZE * dinfo->comp_info[0].v_samp_factor;
+    for (int i = 0; i < numYRowsPerBlock; i++) {
+        rowptrs[i] = SkTAddOffset<JSAMPLE>(pixels[0], i * sizeInfo.fYWidthBytes);
+    }
+    for (int i = 0; i < DCTSIZE; i++) {
+        rowptrs[i + 2 * DCTSIZE] = SkTAddOffset<JSAMPLE>(pixels[1], i * sizeInfo.fUWidthBytes);
+        rowptrs[i + 3 * DCTSIZE] = SkTAddOffset<JSAMPLE>(pixels[2], i * sizeInfo.fVWidthBytes);
+    }
+
+    // After each loop iteration, we will increment pointers to Y, U, and V.
+    size_t blockIncrementY = numYRowsPerBlock * sizeInfo.fYWidthBytes;
+    size_t blockIncrementU = DCTSIZE * sizeInfo.fUWidthBytes;
+    size_t blockIncrementV = DCTSIZE * sizeInfo.fVWidthBytes;
+
+    uint32_t numRowsPerBlock = numYRowsPerBlock;
+
+    // We intentionally round down here, as this first loop will only handle
+    // full block rows.  As a special case at the end, we will handle any
+    // remaining rows that do not make up a full block.
+    const int numIters = dinfo->output_height / numRowsPerBlock;
+    for (int i = 0; i < numIters; i++) {
+        JDIMENSION linesRead = jpeg_read_raw_data(dinfo, yuv, numRowsPerBlock);
+        if (linesRead < numRowsPerBlock) {
+            // FIXME: Handle incomplete YUV decodes without signalling an error.
+            return kInvalidInput;
+        }
+
+        // Update rowptrs.
+        for (int i = 0; i < numYRowsPerBlock; i++) {
+            rowptrs[i] += blockIncrementY;
+        }
+        for (int i = 0; i < DCTSIZE; i++) {
+            rowptrs[i + 2 * DCTSIZE] += blockIncrementU;
+            rowptrs[i + 3 * DCTSIZE] += blockIncrementV;
+        }
+    }
+
+    uint32_t remainingRows = dinfo->output_height - dinfo->output_scanline;
+    SkASSERT(remainingRows == dinfo->output_height % numRowsPerBlock);
+    SkASSERT(dinfo->output_scanline == numIters * numRowsPerBlock);
+    if (remainingRows > 0) {
+        // libjpeg-turbo needs memory to be padded by the block sizes.  We will fulfill
+        // this requirement using a dummy row buffer.
+        // FIXME: Should SkCodec have an extra memory buffer that can be shared among
+        //        all of the implementations that use temporary/garbage memory?
+        SkAutoTMalloc<JSAMPLE> dummyRow(sizeInfo.fYWidthBytes);
+        for (int i = remainingRows; i < numYRowsPerBlock; i++) {
+            rowptrs[i] = dummyRow.get();
+        }
+        int remainingUVRows = dinfo->comp_info[1].downsampled_height - DCTSIZE * numIters;
+        for (int i = remainingUVRows; i < DCTSIZE; i++) {
+            rowptrs[i + 2 * DCTSIZE] = dummyRow.get();
+            rowptrs[i + 3 * DCTSIZE] = dummyRow.get();
+        }
+
+        JDIMENSION linesRead = jpeg_read_raw_data(dinfo, yuv, numRowsPerBlock);
+        if (linesRead < remainingRows) {
+            // FIXME: Handle incomplete YUV decodes without signalling an error.
+            return kInvalidInput;
+        }
+    }
+
+    return kSuccess;
+}
diff --git a/src/codec/SkJpegCodec.h b/src/codec/SkJpegCodec.h
index 8e2db81b73..283dd8fe37 100644
--- a/src/codec/SkJpegCodec.h
+++ b/src/codec/SkJpegCodec.h
@@ -48,6 +48,10 @@ protected:
     Result onGetPixels(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes, const Options&,
             SkPMColor*, int*, int*) override;
 
+    bool onQueryYUV8(YUVSizeInfo* sizeInfo, SkYUVColorSpace* colorSpace) const override;
+
+    Result onGetYUV8Planes(const YUVSizeInfo& sizeInfo, void* pixels[3]) override;
+
     SkEncodedFormat onGetEncodedFormat() const override {
         return kJPEG_SkEncodedFormat;
     }