image/decoders/nsIconDecoder.cpp

   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   // FIXME(aosmond): On OSX we get the icon in device space and already
  58   // premultiplied, so we can't support the surface flags with icons right now.
  59   SurfacePipeFlags pipeFlags = SurfacePipeFlags();
  60   if (transform) {
  61     if (mCMSMode == CMSMode::All) {
  62       mTransform = GetCMSsRGBTransform(format);
  63     }
  64
  65     if (!(GetSurfaceFlags() & SurfaceFlags::NO_PREMULTIPLY_ALPHA)) {
  66       pipeFlags |= SurfacePipeFlags::PREMULTIPLY_ALPHA;
  67     }
  68   }
  69
  70   // The input is 32bpp, so we expect 4 bytes of data per pixel.
  71   mBytesPerRow = width * 4;
  72
  73   // Post our size to the superclass.
  74   PostSize(width, height);
  75
  76   // Icons have alpha.
  77   PostHasTransparency();
  78
  79   // If we're doing a metadata decode, we're done.
  80   if (IsMetadataDecode()) {
  81     return Transition::TerminateSuccess();
  82   }
  83
  84   MOZ_ASSERT(!mImageData, "Already have a buffer allocated?");
  85   Maybe<SurfacePipe> pipe = SurfacePipeFactory::CreateSurfacePipe(
  86       this, Size(), OutputSize(), FullFrame(), format, SurfaceFormat::OS_RGBA,
  87       /* aAnimParams */ Nothing(), mTransform, pipeFlags);
  88   if (!pipe) {
  89     return Transition::TerminateFailure();
  90   }
  91
  92   mPipe = std::move(*pipe);
  93
  94   MOZ_ASSERT(mImageData, "Should have a buffer now");
  95
  96   return Transition::To(State::ROW_OF_PIXELS, mBytesPerRow);
  97 }
  98
  99 LexerTransition<nsIconDecoder::State> nsIconDecoder::ReadRowOfPixels(
 100     const char* aData, size_t aLength) {
 101   MOZ_ASSERT(aLength % 4 == 0, "Rows should contain a multiple of four bytes");
 102
 103   auto result = mPipe.WriteBuffer(reinterpret_cast<const uint32_t*>(aData));
 104   MOZ_ASSERT(result != WriteState::FAILURE);
 105
 106   Maybe<SurfaceInvalidRect> invalidRect = mPipe.TakeInvalidRect();
 107   if (invalidRect) {
 108     PostInvalidation(invalidRect->mInputSpaceRect,
 109                      Some(invalidRect->mOutputSpaceRect));
 110   }
 111
 112   return result == WriteState::FINISHED
 113              ? Transition::To(State::FINISH, 0)
 114              : Transition::To(State::ROW_OF_PIXELS, mBytesPerRow);
 115 }
 116
 117 LexerTransition<nsIconDecoder::State> nsIconDecoder::Finish() {
 118   PostFrameStop();
 119   PostDecodeDone();
 120
 121   return Transition::TerminateSuccess();
 122 }
 123
 124 }  // namespace image
 125 }  // namespace mozilla