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-rw-r--r--image/decoders/nsIconDecoder.cpp128
1 files changed, 128 insertions, 0 deletions
diff --git a/image/decoders/nsIconDecoder.cpp b/image/decoders/nsIconDecoder.cpp
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+++ b/image/decoders/nsIconDecoder.cpp
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+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsIconDecoder.h"
+#include "RasterImage.h"
+#include "SurfacePipeFactory.h"
+
+using namespace mozilla::gfx;
+
+namespace mozilla {
+namespace image {
+
+static const uint32_t ICON_HEADER_SIZE = 2;
+
+nsIconDecoder::nsIconDecoder(RasterImage* aImage)
+ : Decoder(aImage)
+ , mLexer(Transition::To(State::HEADER, ICON_HEADER_SIZE),
+ Transition::TerminateSuccess())
+ , mBytesPerRow() // set by ReadHeader()
+{
+ // Nothing to do
+}
+
+nsIconDecoder::~nsIconDecoder()
+{ }
+
+LexerResult
+nsIconDecoder::DoDecode(SourceBufferIterator& aIterator, IResumable* aOnResume)
+{
+ MOZ_ASSERT(!HasError(), "Shouldn't call DoDecode after error!");
+
+ return mLexer.Lex(aIterator, aOnResume,
+ [=](State aState, const char* aData, size_t aLength) {
+ switch (aState) {
+ case State::HEADER:
+ return ReadHeader(aData);
+ case State::ROW_OF_PIXELS:
+ return ReadRowOfPixels(aData, aLength);
+ case State::FINISH:
+ return Finish();
+ default:
+ MOZ_CRASH("Unknown State");
+ }
+ });
+}
+
+LexerTransition<nsIconDecoder::State>
+nsIconDecoder::ReadHeader(const char* aData)
+{
+ // Grab the width and height.
+ uint8_t width = uint8_t(aData[0]);
+ uint8_t height = uint8_t(aData[1]);
+
+ // The input is 32bpp, so we expect 4 bytes of data per pixel.
+ mBytesPerRow = width * 4;
+
+ // Post our size to the superclass.
+ PostSize(width, height);
+
+ // Icons have alpha.
+ PostHasTransparency();
+
+ // If we're doing a metadata decode, we're done.
+ if (IsMetadataDecode()) {
+ return Transition::TerminateSuccess();
+ }
+
+ MOZ_ASSERT(!mImageData, "Already have a buffer allocated?");
+ Maybe<SurfacePipe> pipe =
+ SurfacePipeFactory::CreateSurfacePipe(this, 0, Size(), OutputSize(),
+ FullFrame(), SurfaceFormat::B8G8R8A8,
+ SurfacePipeFlags());
+ if (!pipe) {
+ return Transition::TerminateFailure();
+ }
+
+ mPipe = Move(*pipe);
+
+ MOZ_ASSERT(mImageData, "Should have a buffer now");
+
+ return Transition::To(State::ROW_OF_PIXELS, mBytesPerRow);
+}
+
+LexerTransition<nsIconDecoder::State>
+nsIconDecoder::ReadRowOfPixels(const char* aData, size_t aLength)
+{
+ MOZ_ASSERT(aLength % 4 == 0, "Rows should contain a multiple of four bytes");
+
+ auto result = mPipe.WritePixels<uint32_t>([&]() -> NextPixel<uint32_t> {
+ if (aLength == 0) {
+ return AsVariant(WriteState::NEED_MORE_DATA); // Done with this row.
+ }
+
+ uint32_t pixel;
+ memcpy(&pixel, aData, 4);
+ aData += 4;
+ aLength -= 4;
+
+ return AsVariant(pixel);
+ });
+
+ MOZ_ASSERT(result != WriteState::FAILURE);
+
+ Maybe<SurfaceInvalidRect> invalidRect = mPipe.TakeInvalidRect();
+ if (invalidRect) {
+ PostInvalidation(invalidRect->mInputSpaceRect,
+ Some(invalidRect->mOutputSpaceRect));
+ }
+
+ return result == WriteState::FINISHED
+ ? Transition::To(State::FINISH, 0)
+ : Transition::To(State::ROW_OF_PIXELS, mBytesPerRow);
+}
+
+LexerTransition<nsIconDecoder::State>
+nsIconDecoder::Finish()
+{
+ PostFrameStop();
+ PostDecodeDone();
+
+ return Transition::TerminateSuccess();
+}
+
+} // namespace image
+} // namespace mozilla