Prototype of RAW decoding in Skia.

src/codec/SkRawCodec.cpp

+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkCodec.h"
+#include "SkRawCodec.h"
+#include "SkCodecPriv.h"
+#include "SkColorPriv.h"
+#include "SkJpegCodec.h"
+#include "SkStream.h"
+#include "SkStreamPriv.h"
+#include "SkSwizzler.h"
+#include "SkTemplates.h"
+#include "SkTypes.h"
+
+#include "dng_color_space.h"
+#include "dng_exceptions.h"
+#include "dng_host.h"
+#include "dng_info.h"
+#include "dng_render.h"
+#include "dng_stream.h"
+
+#include "src/piex.h"
+
+#include <cmath>
+#include <cstring>
+#include <memory>
+#include <vector>
+
+namespace {
+
+/* 
+ * For the dng sdk stream implementation we need to provide the full
+ * length of the image file. However, that is not too bad because we
+ * would need it anyway for the dng rendering pipeline.
+ */
+class SkDngStream : public dng_stream {
+public:
+    SkDngStream(const void* data, size_t size)
+        : fData(data)
+        , fDataSize(size) {}
+
+    ~SkDngStream() override {}
+
+protected:
+    uint64 DoGetLength() override { return fDataSize; }
+    void DoRead(void* data, uint32 count, uint64 offset) override {
+        if (fDataSize < offset + count) {
+            ThrowReadFile();
+        }
+        memcpy(data, reinterpret_cast<const uint8*>(fData) + offset, count);
+    }
+
+private:
+    // The memory is owned by the codec, here is only a pointer.
+    const void* fData;
+    const size_t fDataSize;
+};
+
+class SkPiexStream : public ::piex::StreamInterface {
+   public:
+    SkPiexStream(const void* data, size_t size)
+        : fData(data)
+        , fDataSize(size) {}
+
+    ::piex::Error GetData(const size_t offset, const size_t length,
+                          uint8* data) override {
+        if (offset >= fDataSize || fDataSize - offset < length) {
+          return ::piex::Error::kFail;
+        }
+        memcpy(data, reinterpret_cast<const uint8*>(fData) + offset, length);
+        return ::piex::Error::kOk;
+    }
+
+   private:
+    // The memory is owned by the codec, here is only a pointer.
+    const void* fData;
+    const size_t fDataSize;
+};
+
+dng_negative* ReadDng(dng_stream* stream, dng_host* host, dng_info* info) {
+    const uint32 kPreferredSize = 0;
+    const uint32 kMinimumSize = 0;
+    const uint32 kMaximumSize = 0;
+    SkAutoTDelete<dng_negative> negative;
+    try {
+        host->SetPreferredSize(kPreferredSize);
+        host->SetMinimumSize(kMinimumSize);
+        host->SetMaximumSize(kMaximumSize);
+
+        host->ValidateSizes();
+
+        // Read stage 1 image into the negative.
+        {
+            info->Parse(*host, *stream);
+            info->PostParse(*host);
+
+            if (!info->IsValidDNG()) {
+                return nullptr;
+            }
+
+            negative.reset(host->Make_dng_negative());
+            negative->Parse(*host, *stream, *info);
+            negative->PostParse(*host, *stream, *info);
+        }
+
+        negative->SynchronizeMetadata();
+    } catch (...) {
+        return nullptr;
+    }
+
+    return negative.release();
+}
+
+bool PrepareStage3(dng_stream* stream, dng_host* host, dng_info* info,
+                   dng_negative* negative) {
+    if (negative->Stage3Image() == nullptr) {
+        negative->ReadStage1Image(*host, *stream, *info);
+
+        if (info->fMaskIndex != -1) {
+            negative->ReadTransparencyMask(*host, *stream, *info);
+        }
+
+        negative->ValidateRawImageDigest(*host);
+        if (negative->IsDamaged()) {
+            return false;
+        }
+
+        const int32 kMosaicPlane = -1;
+        negative->BuildStage2Image(*host);
+        negative->BuildStage3Image(*host, kMosaicPlane);
+    }
+
+    return true;
+}
+
+}  // namespace
+
+SkCodec* SkRawCodec::NewFromStream(SkStream* stream) {
+    SkAutoMalloc data;
+    const size_t dataSize = SkCopyStreamToStorage(&data, stream);
+
+    SkPiexStream piexStream(data.get(), dataSize);
+    ::piex::PreviewImageData imageData;
+    if (::piex::IsRaw(&piexStream) &&
+        ::piex::GetPreviewImageData(&piexStream, &imageData) == ::piex::Error::kOk)
+    {
+        return SkJpegCodec::NewFromStream(new SkMemoryStream(
+                reinterpret_cast<const uint8*>(data.get()) + imageData.jpeg_offset,
+                imageData.jpeg_length, true));
+    }
+
+    SkDngStream dngStream(data.get(), dataSize);
+    dng_host host;
+    dng_info info;
+    SkAutoTDelete<dng_negative> negative(ReadDng(&dngStream, &host, &info));
+    if (!negative) {
+        return nullptr;
+    }
+
+    const SkImageInfo& imageInfo = SkImageInfo::Make(
+        negative->DefaultCropSizeH().As_real64(),
+        negative->DefaultCropSizeV().As_real64(),
+        kN32_SkColorType, kOpaque_SkAlphaType);
+    return new SkRawCodec(imageInfo, dataSize, data.detach());
+}
+
+SkCodec::Result SkRawCodec::onGetPixels(const SkImageInfo& requestedInfo, void* dst,
+                                        size_t dstRowBytes, const Options& options,
+                                        SkPMColor ctable[], int* ctableCount,
+                                        int* rowsDecoded) {
+    const int width = requestedInfo.width();
+    const int height = requestedInfo.height();
+    SkAutoTDelete<dng_image> finalDngImage;
+    try {
+        SkDngStream dngStream(fDngStorage, fDngLength);

[scroggo, 2016/01/07 13:53:20]

Oh, I see the problem - this is a tab, but it should be indented using spaces.

(I've recently switched to the new UI for the code review too, which does not
distinguish between tabs and spaces. Looking in the old UI, I can see that it is
marked with a red ">>" signifying a tab. So it probably looks correct in your
editor, but does not line up properly in the new UI.)

[yujieqin, 2016/01/07 15:52:01]

Got it and fixed.

+
+        dng_host host;
+        dng_info info;
+        SkAutoTDelete<dng_negative> negative(ReadDng(&dngStream, &host, &info));
+        if (!negative ||
+            !PrepareStage3(&dngStream, &host, &info, negative.get()))

[scroggo, 2016/01/07 13:53:20]

I think this can fit on one line now? Then you can leave the brace on the same
line as well:

if (!negative || !PrepareStage3(...)) {

[yujieqin, 2016/01/07 15:52:01]

Done.

+        {
+            return kInvalidInput;
+        }
+
+        dng_render render(host, *negative);
+        render.SetFinalSpace(dng_space_sRGB::Get());
+        render.SetFinalPixelType(ttByte);
+
+        finalDngImage.reset(render.Render());
+    } catch (...) {
+        return kInvalidInput;
+    }
+
+    void* dstRow = dst;
+    uint8 srcRow[width * 3];
+    SkAutoTDelete<SkSwizzler> swizzler(SkSwizzler::CreateSwizzler(
+            SkSwizzler::kRGB, nullptr, requestedInfo, options));
+    SkASSERT(swizzler);
+    for (int i = 0; i < height; ++i) {
+        dng_pixel_buffer buffer;
+        buffer.fData = &srcRow[0];
+        buffer.fArea = dng_rect(i, 0, i + 1, width);
+        buffer.fPlane = 0;
+        buffer.fPlanes = 3;
+        buffer.fColStep = buffer.fPlanes;
+        buffer.fPlaneStep = 1;
+        buffer.fPixelType = ttByte;
+        buffer.fPixelSize = sizeof(uint8);
+        buffer.fRowStep = sizeof(srcRow);
+
+        try {
+            finalDngImage->Get(buffer, dng_image::edge_zero);
+        } catch (...) {

[scroggo, 2016/01/07 13:53:20]

Again, this uses a TAB, but it should be spaces.

[yujieqin, 2016/01/07 15:52:01]

Done.

+            return kInvalidInput;
+        }
+
+        swizzler->swizzle(dstRow, &srcRow[0]);
+        dstRow = SkTAddOffset<void>(dstRow, dstRowBytes);
+    }
+    return kSuccess;
+}
+
+SkRawCodec::~SkRawCodec() {
+    sk_free(fDngStorage);
+}
+
+SkRawCodec::SkRawCodec(const SkImageInfo& srcInfo, size_t length, void* storage)
+    : INHERITED(srcInfo, nullptr), fDngLength(length), fDngStorage(storage) {}