/* -*- 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, Size(), OutputSize(),

                                          FullFrame(), SurfaceFormat::B8G8R8A8,

                                          /* aAnimParams */ Nothing(),

                                          SurfacePipeFlags());

  if (!pipe) {

    return Transition::TerminateFailure();

  }

  mPipe = std::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