tor-browser

The Tor Browser
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nsIconDecoder.cpp (4409B)

      1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
      3 /* This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #include "nsIconDecoder.h"
      8 #include "RasterImage.h"
      9 #include "SurfacePipeFactory.h"
     10 #include "gfxPlatform.h"
     11 
     12 using namespace mozilla::gfx;
     13 
     14 namespace mozilla {
     15 namespace image {
     16 
     17 static const uint32_t ICON_HEADER_SIZE = 4;
     18 
     19 nsIconDecoder::nsIconDecoder(RasterImage* aImage)
     20    : Decoder(aImage),
     21      mLexer(Transition::To(State::HEADER, ICON_HEADER_SIZE),
     22             Transition::TerminateSuccess()),
     23      mBytesPerRow()  // set by ReadHeader()
     24 {
     25  // Nothing to do
     26 }
     27 
     28 nsIconDecoder::~nsIconDecoder() {}
     29 
     30 LexerResult nsIconDecoder::DoDecode(SourceBufferIterator& aIterator,
     31                                    IResumable* aOnResume) {
     32  MOZ_ASSERT(!HasError(), "Shouldn't call DoDecode after error!");
     33 
     34  return mLexer.Lex(aIterator, aOnResume,
     35                    [=](State aState, const char* aData, size_t aLength) {
     36                      switch (aState) {
     37                        case State::HEADER:
     38                          return ReadHeader(aData);
     39                        case State::ROW_OF_PIXELS:
     40                          return ReadRowOfPixels(aData, aLength);
     41                        case State::FINISH:
     42                          return Finish();
     43                        default:
     44                          MOZ_CRASH("Unknown State");
     45                      }
     46                    });
     47 }
     48 
     49 LexerTransition<nsIconDecoder::State> nsIconDecoder::ReadHeader(
     50    const char* aData) {
     51  // Grab the width and height.
     52  uint8_t width = uint8_t(aData[0]);
     53  uint8_t height = uint8_t(aData[1]);
     54  SurfaceFormat format = SurfaceFormat(aData[2]);
     55  bool transform = bool(aData[3]);
     56 
     57  if (format != SurfaceFormat::B8G8R8A8 && format != SurfaceFormat::B8G8R8X8 &&
     58      format != SurfaceFormat::R8G8B8A8 && format != SurfaceFormat::R8G8B8X8 &&
     59      format != SurfaceFormat::A8R8G8B8 && format != SurfaceFormat::X8R8G8B8) {
     60    return Transition::TerminateFailure();
     61  }
     62 
     63  // FIXME(aosmond): On OSX we get the icon in device space and already
     64  // premultiplied, so we can't support the surface flags with icons right now.
     65  SurfacePipeFlags pipeFlags = SurfacePipeFlags();
     66  if (transform) {
     67    if (mCMSMode == CMSMode::All) {
     68      mTransform = GetCMSsRGBTransform(format);
     69    }
     70 
     71    if (!(GetSurfaceFlags() & SurfaceFlags::NO_PREMULTIPLY_ALPHA)) {
     72      pipeFlags |= SurfacePipeFlags::PREMULTIPLY_ALPHA;
     73    }
     74  }
     75 
     76  // The input is 32bpp, so we expect 4 bytes of data per pixel.
     77  mBytesPerRow = width * 4;
     78 
     79  // Post our size to the superclass.
     80  PostSize(width, height);
     81 
     82  if (WantsFrameCount()) {
     83    PostFrameCount(/* aFrameCount */ 1);
     84  }
     85 
     86  // Icons have alpha.
     87  PostHasTransparency();
     88 
     89  // If we're doing a metadata decode, we're done.
     90  if (IsMetadataDecode()) {
     91    return Transition::TerminateSuccess();
     92  }
     93 
     94  MOZ_ASSERT(!mImageData, "Already have a buffer allocated?");
     95  Maybe<SurfacePipe> pipe = SurfacePipeFactory::CreateSurfacePipe(
     96      this, Size(), OutputSize(), FullFrame(), format, SurfaceFormat::OS_RGBA,
     97      /* aAnimParams */ Nothing(), mTransform, pipeFlags);
     98  if (!pipe) {
     99    return Transition::TerminateFailure();
    100  }
    101 
    102  mPipe = std::move(*pipe);
    103 
    104  MOZ_ASSERT(mImageData, "Should have a buffer now");
    105 
    106  return Transition::To(State::ROW_OF_PIXELS, mBytesPerRow);
    107 }
    108 
    109 LexerTransition<nsIconDecoder::State> nsIconDecoder::ReadRowOfPixels(
    110    const char* aData, size_t aLength) {
    111  MOZ_ASSERT(aLength % 4 == 0, "Rows should contain a multiple of four bytes");
    112 
    113  auto result = mPipe.WriteBuffer(reinterpret_cast<const uint32_t*>(aData));
    114  MOZ_ASSERT(result != WriteState::FAILURE);
    115 
    116  Maybe<SurfaceInvalidRect> invalidRect = mPipe.TakeInvalidRect();
    117  if (invalidRect) {
    118    PostInvalidation(invalidRect->mInputSpaceRect,
    119                     Some(invalidRect->mOutputSpaceRect));
    120  }
    121 
    122  return result == WriteState::FINISHED
    123             ? Transition::To(State::FINISH, 0)
    124             : Transition::To(State::ROW_OF_PIXELS, mBytesPerRow);
    125 }
    126 
    127 LexerTransition<nsIconDecoder::State> nsIconDecoder::Finish() {
    128  PostFrameStop();
    129  PostDecodeDone();
    130 
    131  return Transition::TerminateSuccess();
    132 }
    133 
    134 }  // namespace image
    135 }  // namespace mozilla