1 files changed, 128 insertions, 0 deletions
diff --git a/image/decoders/nsIconDecoder.cpp b/image/decoders/nsIconDecoder.cpp
new file mode 100644
index 000000000..9ca63f5ad
--- /dev/null
+++ b/image/decoders/nsIconDecoder.cpp
@@ -0,0 +1,128 @@
+/* -*- 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