Add m-esr52 at 52.6.0

1 files changed, 673 insertions, 0 deletions

diff --git a/image/decoders/nsICODecoder.cpp b/image/decoders/nsICODecoder.cpp
new file mode 100644
index 000000000..633bb1255
--- /dev/null
+++ b/image/decoders/nsICODecoder.cpp
@@ -0,0 +1,673 @@
+/* vim:set tw=80 expandtab softtabstop=2 ts=2 sw=2: */
+/* 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/. */
+
+/* This is a Cross-Platform ICO Decoder, which should work everywhere, including
+ * Big-Endian machines like the PowerPC. */
+
+#include "nsICODecoder.h"
+
+#include <stdlib.h>
+
+#include "mozilla/EndianUtils.h"
+#include "mozilla/Move.h"
+
+#include "RasterImage.h"
+
+using namespace mozilla::gfx;
+
+namespace mozilla {
+namespace image {
+
+// Constants.
+static const uint32_t ICOHEADERSIZE = 6;
+static const uint32_t BITMAPINFOSIZE = bmp::InfoHeaderLength::WIN_ICO;
+
+// ----------------------------------------
+// Actual Data Processing
+// ----------------------------------------
+
+// Obtains the number of colors from the bits per pixel
+uint16_t
+nsICODecoder::GetNumColors()
+{
+  uint16_t numColors = 0;
+  if (mBPP <= 8) {
+    switch (mBPP) {
+    case 1:
+      numColors = 2;
+      break;
+    case 4:
+      numColors = 16;
+      break;
+    case 8:
+      numColors = 256;
+      break;
+    default:
+      numColors = (uint16_t)-1;
+    }
+  }
+  return numColors;
+}
+
+nsICODecoder::nsICODecoder(RasterImage* aImage)
+  : Decoder(aImage)
+  , mLexer(Transition::To(ICOState::HEADER, ICOHEADERSIZE),
+           Transition::TerminateSuccess())
+  , mBiggestResourceColorDepth(0)
+  , mBestResourceDelta(INT_MIN)
+  , mBestResourceColorDepth(0)
+  , mNumIcons(0)
+  , mCurrIcon(0)
+  , mBPP(0)
+  , mMaskRowSize(0)
+  , mCurrMaskLine(0)
+  , mIsCursor(false)
+  , mHasMaskAlpha(false)
+{ }
+
+nsresult
+nsICODecoder::FinishInternal()
+{
+  // We shouldn't be called in error cases
+  MOZ_ASSERT(!HasError(), "Shouldn't call FinishInternal after error!");
+
+  return GetFinalStateFromContainedDecoder();
+}
+
+nsresult
+nsICODecoder::FinishWithErrorInternal()
+{
+  return GetFinalStateFromContainedDecoder();
+}
+
+nsresult
+nsICODecoder::GetFinalStateFromContainedDecoder()
+{
+  if (!mContainedDecoder) {
+    return NS_OK;
+  }
+
+  MOZ_ASSERT(mContainedSourceBuffer,
+             "Should have a SourceBuffer if we have a decoder");
+
+  // Let the contained decoder finish up if necessary.
+  if (!mContainedSourceBuffer->IsComplete()) {
+    mContainedSourceBuffer->Complete(NS_OK);
+    mContainedDecoder->Decode();
+  }
+
+  // Make our state the same as the state of the contained decoder.
+  mDecodeDone = mContainedDecoder->GetDecodeDone();
+  mProgress |= mContainedDecoder->TakeProgress();
+  mInvalidRect.UnionRect(mInvalidRect, mContainedDecoder->TakeInvalidRect());
+  mCurrentFrame = mContainedDecoder->GetCurrentFrameRef();
+
+  // Propagate errors.
+  nsresult rv = HasError() || mContainedDecoder->HasError()
+              ? NS_ERROR_FAILURE
+              : NS_OK;
+
+  MOZ_ASSERT(NS_FAILED(rv) || !mCurrentFrame || mCurrentFrame->IsFinished());
+  return rv;
+}
+
+bool
+nsICODecoder::CheckAndFixBitmapSize(int8_t* aBIH)
+{
+  // Get the width from the BMP file information header. This is
+  // (unintuitively) a signed integer; see the documentation at:
+  //
+  //   https://msdn.microsoft.com/en-us/library/windows/desktop/dd183376(v=vs.85).aspx
+  //
+  // However, we reject negative widths since they aren't meaningful.
+  const int32_t width = LittleEndian::readInt32(aBIH + 4);
+  if (width <= 0 || width > 256) {
+    return false;
+  }
+
+  // Verify that the BMP width matches the width we got from the ICO directory
+  // entry. If not, decoding fails, because if we were to allow it to continue
+  // the intrinsic size of the image wouldn't match the size of the decoded
+  // surface.
+  if (width != int32_t(GetRealWidth())) {
+    return false;
+  }
+
+  // Get the height from the BMP file information header. This is also signed,
+  // but in this case negative values are meaningful; see below.
+  int32_t height = LittleEndian::readInt32(aBIH + 8);
+  if (height == 0) {
+    return false;
+  }
+
+  // BMPs can be stored inverted by having a negative height.
+  // XXX(seth): Should we really be writing the absolute value into the BIH
+  // below? Seems like this could be problematic for inverted BMPs.
+  height = abs(height);
+
+  // The height field is double the actual height of the image to account for
+  // the AND mask. This is true even if the AND mask is not present.
+  height /= 2;
+  if (height > 256) {
+    return false;
+  }
+
+  // Verify that the BMP height matches the height we got from the ICO directory
+  // entry. If not, again, decoding fails.
+  if (height != int32_t(GetRealHeight())) {
+    return false;
+  }
+
+  // Fix the BMP height in the BIH so that the BMP decoder, which does not know
+  // about the AND mask that may follow the actual bitmap, can work properly.
+  LittleEndian::writeInt32(aBIH + 8, GetRealHeight());
+
+  return true;
+}
+
+LexerTransition<ICOState>
+nsICODecoder::ReadHeader(const char* aData)
+{
+  // If the third byte is 1, this is an icon. If 2, a cursor.
+  if ((aData[2] != 1) && (aData[2] != 2)) {
+    return Transition::TerminateFailure();
+  }
+  mIsCursor = (aData[2] == 2);
+
+  // The fifth and sixth bytes specify the number of resources in the file.
+  mNumIcons = LittleEndian::readUint16(aData + 4);
+  if (mNumIcons == 0) {
+    return Transition::TerminateSuccess(); // Nothing to do.
+  }
+
+  // Downscale-during-decode can end up decoding different resources in the ICO
+  // file depending on the target size. Since the resources are not necessarily
+  // scaled versions of the same image, some may be transparent and some may not
+  // be. We could be precise about transparency if we decoded the metadata of
+  // every resource, but for now we don't and it's safest to assume that
+  // transparency could be present.
+  PostHasTransparency();
+
+  return Transition::To(ICOState::DIR_ENTRY, ICODIRENTRYSIZE);
+}
+
+size_t
+nsICODecoder::FirstResourceOffset() const
+{
+  MOZ_ASSERT(mNumIcons > 0,
+             "Calling FirstResourceOffset before processing header");
+
+  // The first resource starts right after the directory, which starts right
+  // after the ICO header.
+  return ICOHEADERSIZE + mNumIcons * ICODIRENTRYSIZE;
+}
+
+LexerTransition<ICOState>
+nsICODecoder::ReadDirEntry(const char* aData)
+{
+  mCurrIcon++;
+
+  // Read the directory entry.
+  IconDirEntry e;
+  e.mWidth       = aData[0];
+  e.mHeight      = aData[1];
+  e.mColorCount  = aData[2];
+  e.mReserved    = aData[3];
+  e.mPlanes      = LittleEndian::readUint16(aData + 4);
+  e.mBitCount    = LittleEndian::readUint16(aData + 6);
+  e.mBytesInRes  = LittleEndian::readUint32(aData + 8);
+  e.mImageOffset = LittleEndian::readUint32(aData + 12);
+
+  // If an explicit output size was specified, we'll try to select the resource
+  // that matches it best below.
+  const Maybe<IntSize> desiredSize = ExplicitOutputSize();
+
+  // Determine if this is the biggest resource we've seen so far. We always use
+  // the biggest resource for the intrinsic size, and if we don't have a
+  // specific desired size, we select it as the best resource as well.
+  IntSize entrySize(GetRealWidth(e), GetRealHeight(e));
+  if (e.mBitCount >= mBiggestResourceColorDepth &&
+      entrySize.width * entrySize.height >=
+        mBiggestResourceSize.width * mBiggestResourceSize.height) {
+    mBiggestResourceSize = entrySize;
+    mBiggestResourceColorDepth = e.mBitCount;
+    mBiggestResourceHotSpot = IntSize(e.mXHotspot, e.mYHotspot);
+
+    if (!desiredSize) {
+      mDirEntry = e;
+    }
+  }
+
+  if (desiredSize) {
+    // Calculate the delta between this resource's size and the desired size, so
+    // we can see if it is better than our current-best option.  In the case of
+    // several equally-good resources, we use the last one. "Better" in this
+    // case is determined by |delta|, a measure of the difference in size
+    // between the entry we've found and the desired size. We will choose the
+    // smallest resource that is greater than or equal to the desired size (i.e.
+    // we assume it's better to downscale a larger icon than to upscale a
+    // smaller one).
+    int32_t delta = std::min(entrySize.width - desiredSize->width,
+                             entrySize.height - desiredSize->height);
+    if (e.mBitCount >= mBestResourceColorDepth &&
+        ((mBestResourceDelta < 0 && delta >= mBestResourceDelta) ||
+         (delta >= 0 && delta <= mBestResourceDelta))) {
+      mBestResourceDelta = delta;
+      mBestResourceColorDepth = e.mBitCount;
+      mDirEntry = e;
+    }
+  }
+
+  if (mCurrIcon == mNumIcons) {
+    // Ensure the resource we selected has an offset past the ICO headers.
+    if (mDirEntry.mImageOffset < FirstResourceOffset()) {
+      return Transition::TerminateFailure();
+    }
+
+    // If this is a cursor, set the hotspot. We use the hotspot from the biggest
+    // resource since we also use that resource for the intrinsic size.
+    if (mIsCursor) {
+      mImageMetadata.SetHotspot(mBiggestResourceHotSpot.width,
+                                mBiggestResourceHotSpot.height);
+    }
+
+    // We always report the biggest resource's size as the intrinsic size; this
+    // is necessary for downscale-during-decode to work since we won't even
+    // attempt to *upscale* while decoding.
+    PostSize(mBiggestResourceSize.width, mBiggestResourceSize.height);
+    if (IsMetadataDecode()) {
+      return Transition::TerminateSuccess();
+    }
+
+    // If the resource we selected matches the output size perfectly, we don't
+    // need to do any downscaling.
+    if (GetRealSize() == OutputSize()) {
+      MOZ_ASSERT_IF(desiredSize, GetRealSize() == *desiredSize);
+      MOZ_ASSERT_IF(!desiredSize, GetRealSize() == Size());
+      mDownscaler.reset();
+    }
+
+    size_t offsetToResource = mDirEntry.mImageOffset - FirstResourceOffset();
+    return Transition::ToUnbuffered(ICOState::FOUND_RESOURCE,
+                                    ICOState::SKIP_TO_RESOURCE,
+                                    offsetToResource);
+  }
+
+  return Transition::To(ICOState::DIR_ENTRY, ICODIRENTRYSIZE);
+}
+
+LexerTransition<ICOState>
+nsICODecoder::SniffResource(const char* aData)
+{
+  // We use the first PNGSIGNATURESIZE bytes to determine whether this resource
+  // is a PNG or a BMP.
+  bool isPNG = !memcmp(aData, nsPNGDecoder::pngSignatureBytes,
+                       PNGSIGNATURESIZE);
+  if (isPNG) {
+    // Create a PNG decoder which will do the rest of the work for us.
+    mContainedSourceBuffer = new SourceBuffer();
+    mContainedSourceBuffer->ExpectLength(mDirEntry.mBytesInRes);
+    mContainedDecoder =
+      DecoderFactory::CreateDecoderForICOResource(DecoderType::PNG,
+                                                  WrapNotNull(mContainedSourceBuffer),
+                                                  WrapNotNull(this));
+
+    if (!WriteToContainedDecoder(aData, PNGSIGNATURESIZE)) {
+      return Transition::TerminateFailure();
+    }
+
+    if (mDirEntry.mBytesInRes <= PNGSIGNATURESIZE) {
+      return Transition::TerminateFailure();
+    }
+
+    // Read in the rest of the PNG unbuffered.
+    size_t toRead = mDirEntry.mBytesInRes - PNGSIGNATURESIZE;
+    return Transition::ToUnbuffered(ICOState::FINISHED_RESOURCE,
+                                    ICOState::READ_PNG,
+                                    toRead);
+  } else {
+    // Make sure we have a sane size for the bitmap information header.
+    int32_t bihSize = LittleEndian::readUint32(aData);
+    if (bihSize != static_cast<int32_t>(BITMAPINFOSIZE)) {
+      return Transition::TerminateFailure();
+    }
+
+    // Buffer the first part of the bitmap information header.
+    memcpy(mBIHraw, aData, PNGSIGNATURESIZE);
+
+    // Read in the rest of the bitmap information header.
+    return Transition::To(ICOState::READ_BIH,
+                          BITMAPINFOSIZE - PNGSIGNATURESIZE);
+  }
+}
+
+LexerTransition<ICOState>
+nsICODecoder::ReadPNG(const char* aData, uint32_t aLen)
+{
+  if (!WriteToContainedDecoder(aData, aLen)) {
+    return Transition::TerminateFailure();
+  }
+
+  // Raymond Chen says that 32bpp only are valid PNG ICOs
+  // http://blogs.msdn.com/b/oldnewthing/archive/2010/10/22/10079192.aspx
+  if (!static_cast<nsPNGDecoder*>(mContainedDecoder.get())->IsValidICO()) {
+    return Transition::TerminateFailure();
+  }
+
+  return Transition::ContinueUnbuffered(ICOState::READ_PNG);
+}
+
+LexerTransition<ICOState>
+nsICODecoder::ReadBIH(const char* aData)
+{
+  // Buffer the rest of the bitmap information header.
+  memcpy(mBIHraw + PNGSIGNATURESIZE, aData, BITMAPINFOSIZE - PNGSIGNATURESIZE);
+
+  // Extract the BPP from the BIH header; it should be trusted over the one
+  // we have from the ICO header which is usually set to 0.
+  mBPP = LittleEndian::readUint16(mBIHraw + 14);
+
+  // The ICO format when containing a BMP does not include the 14 byte
+  // bitmap file header. So we create the BMP decoder via the constructor that
+  // tells it to skip this, and pass in the required data (dataOffset) that
+  // would have been present in the header.
+  uint32_t dataOffset = bmp::FILE_HEADER_LENGTH + BITMAPINFOSIZE;
+  if (mDirEntry.mBitCount <= 8) {
+    // The color table is present only if BPP is <= 8.
+    uint16_t numColors = GetNumColors();
+    if (numColors == (uint16_t)-1) {
+      return Transition::TerminateFailure();
+    }
+    dataOffset += 4 * numColors;
+  }
+
+  // Create a BMP decoder which will do most of the work for us; the exception
+  // is the AND mask, which isn't present in standalone BMPs.
+  mContainedSourceBuffer = new SourceBuffer();
+  mContainedSourceBuffer->ExpectLength(mDirEntry.mBytesInRes);
+  mContainedDecoder =
+    DecoderFactory::CreateDecoderForICOResource(DecoderType::BMP,
+                                                WrapNotNull(mContainedSourceBuffer),
+                                                WrapNotNull(this),
+                                                Some(dataOffset));
+  RefPtr<nsBMPDecoder> bmpDecoder =
+    static_cast<nsBMPDecoder*>(mContainedDecoder.get());
+
+  // Verify that the BIH width and height values match the ICO directory entry,
+  // and fix the BIH height value to compensate for the fact that the underlying
+  // BMP decoder doesn't know about AND masks.
+  if (!CheckAndFixBitmapSize(reinterpret_cast<int8_t*>(mBIHraw))) {
+    return Transition::TerminateFailure();
+  }
+
+  // Write out the BMP's bitmap info header.
+  if (!WriteToContainedDecoder(mBIHraw, sizeof(mBIHraw))) {
+    return Transition::TerminateFailure();
+  }
+
+  // Check to make sure we have valid color settings.
+  uint16_t numColors = GetNumColors();
+  if (numColors == uint16_t(-1)) {
+    return Transition::TerminateFailure();
+  }
+
+  // Do we have an AND mask on this BMP? If so, we need to read it after we read
+  // the BMP data itself.
+  uint32_t bmpDataLength = bmpDecoder->GetCompressedImageSize() + 4 * numColors;
+  bool hasANDMask = (BITMAPINFOSIZE + bmpDataLength) < mDirEntry.mBytesInRes;
+  ICOState afterBMPState = hasANDMask ? ICOState::PREPARE_FOR_MASK
+                                      : ICOState::FINISHED_RESOURCE;
+
+  // Read in the rest of the BMP unbuffered.
+  return Transition::ToUnbuffered(afterBMPState,
+                                  ICOState::READ_BMP,
+                                  bmpDataLength);
+}
+
+LexerTransition<ICOState>
+nsICODecoder::ReadBMP(const char* aData, uint32_t aLen)
+{
+  if (!WriteToContainedDecoder(aData, aLen)) {
+    return Transition::TerminateFailure();
+  }
+
+  return Transition::ContinueUnbuffered(ICOState::READ_BMP);
+}
+
+LexerTransition<ICOState>
+nsICODecoder::PrepareForMask()
+{
+  RefPtr<nsBMPDecoder> bmpDecoder =
+    static_cast<nsBMPDecoder*>(mContainedDecoder.get());
+
+  uint16_t numColors = GetNumColors();
+  MOZ_ASSERT(numColors != uint16_t(-1));
+
+  // Determine the length of the AND mask.
+  uint32_t bmpLengthWithHeader =
+    BITMAPINFOSIZE + bmpDecoder->GetCompressedImageSize() + 4 * numColors;
+  MOZ_ASSERT(bmpLengthWithHeader < mDirEntry.mBytesInRes);
+  uint32_t maskLength = mDirEntry.mBytesInRes - bmpLengthWithHeader;
+
+  // If the BMP provides its own transparency, we ignore the AND mask. We can
+  // also obviously ignore it if the image has zero width or zero height.
+  if (bmpDecoder->HasTransparency() ||
+      GetRealWidth() == 0 || GetRealHeight() == 0) {
+    return Transition::ToUnbuffered(ICOState::FINISHED_RESOURCE,
+                                    ICOState::SKIP_MASK,
+                                    maskLength);
+  }
+
+  // Compute the row size for the mask.
+  mMaskRowSize = ((GetRealWidth() + 31) / 32) * 4; // + 31 to round up
+
+  // If the expected size of the AND mask is larger than its actual size, then
+  // we must have a truncated (and therefore corrupt) AND mask.
+  uint32_t expectedLength = mMaskRowSize * GetRealHeight();
+  if (maskLength < expectedLength) {
+    return Transition::TerminateFailure();
+  }
+
+  // If we're downscaling, the mask is the wrong size for the surface we've
+  // produced, so we need to downscale the mask into a temporary buffer and then
+  // combine the mask's alpha values with the color values from the image.
+  if (mDownscaler) {
+    MOZ_ASSERT(bmpDecoder->GetImageDataLength() ==
+                 mDownscaler->TargetSize().width *
+                 mDownscaler->TargetSize().height *
+                 sizeof(uint32_t));
+    mMaskBuffer = MakeUnique<uint8_t[]>(bmpDecoder->GetImageDataLength());
+    nsresult rv = mDownscaler->BeginFrame(GetRealSize(), Nothing(),
+                                          mMaskBuffer.get(),
+                                          /* aHasAlpha = */ true,
+                                          /* aFlipVertically = */ true);
+    if (NS_FAILED(rv)) {
+      return Transition::TerminateFailure();
+    }
+  }
+
+  mCurrMaskLine = GetRealHeight();
+  return Transition::To(ICOState::READ_MASK_ROW, mMaskRowSize);
+}
+
+
+LexerTransition<ICOState>
+nsICODecoder::ReadMaskRow(const char* aData)
+{
+  mCurrMaskLine--;
+
+  uint8_t sawTransparency = 0;
+
+  // Get the mask row we're reading.
+  const uint8_t* mask = reinterpret_cast<const uint8_t*>(aData);
+  const uint8_t* maskRowEnd = mask + mMaskRowSize;
+
+  // Get the corresponding row of the mask buffer (if we're downscaling) or the
+  // decoded image data (if we're not).
+  uint32_t* decoded = nullptr;
+  if (mDownscaler) {
+    // Initialize the row to all white and fully opaque.
+    memset(mDownscaler->RowBuffer(), 0xFF, GetRealWidth() * sizeof(uint32_t));
+
+    decoded = reinterpret_cast<uint32_t*>(mDownscaler->RowBuffer());
+  } else {
+    RefPtr<nsBMPDecoder> bmpDecoder =
+      static_cast<nsBMPDecoder*>(mContainedDecoder.get());
+    uint32_t* imageData = bmpDecoder->GetImageData();
+    if (!imageData) {
+      return Transition::TerminateFailure();
+    }
+
+    decoded = imageData + mCurrMaskLine * GetRealWidth();
+  }
+
+  MOZ_ASSERT(decoded);
+  uint32_t* decodedRowEnd = decoded + GetRealWidth();
+
+  // Iterate simultaneously through the AND mask and the image data.
+  while (mask < maskRowEnd) {
+    uint8_t idx = *mask++;
+    sawTransparency |= idx;
+    for (uint8_t bit = 0x80; bit && decoded < decodedRowEnd; bit >>= 1) {
+      // Clear pixel completely for transparency.
+      if (idx & bit) {
+        *decoded = 0;
+      }
+      decoded++;
+    }
+  }
+
+  if (mDownscaler) {
+    mDownscaler->CommitRow();
+  }
+
+  // If any bits are set in sawTransparency, then we know at least one pixel was
+  // transparent.
+  if (sawTransparency) {
+    mHasMaskAlpha = true;
+  }
+
+  if (mCurrMaskLine == 0) {
+    return Transition::To(ICOState::FINISH_MASK, 0);
+  }
+
+  return Transition::To(ICOState::READ_MASK_ROW, mMaskRowSize);
+}
+
+LexerTransition<ICOState>
+nsICODecoder::FinishMask()
+{
+  // If we're downscaling, we now have the appropriate alpha values in
+  // mMaskBuffer. We just need to transfer them to the image.
+  if (mDownscaler) {
+    // Retrieve the image data.
+    RefPtr<nsBMPDecoder> bmpDecoder =
+      static_cast<nsBMPDecoder*>(mContainedDecoder.get());
+    uint8_t* imageData = reinterpret_cast<uint8_t*>(bmpDecoder->GetImageData());
+    if (!imageData) {
+      return Transition::TerminateFailure();
+    }
+
+    // Iterate through the alpha values, copying from mask to image.
+    MOZ_ASSERT(mMaskBuffer);
+    MOZ_ASSERT(bmpDecoder->GetImageDataLength() > 0);
+    for (size_t i = 3 ; i < bmpDecoder->GetImageDataLength() ; i += 4) {
+      imageData[i] = mMaskBuffer[i];
+    }
+  }
+
+  return Transition::To(ICOState::FINISHED_RESOURCE, 0);
+}
+
+LexerTransition<ICOState>
+nsICODecoder::FinishResource()
+{
+  // Make sure the actual size of the resource matches the size in the directory
+  // entry. If not, we consider the image corrupt.
+  if (mContainedDecoder->HasSize() &&
+      mContainedDecoder->Size() != GetRealSize()) {
+    return Transition::TerminateFailure();
+  }
+
+  return Transition::TerminateSuccess();
+}
+
+LexerResult
+nsICODecoder::DoDecode(SourceBufferIterator& aIterator, IResumable* aOnResume)
+{
+  MOZ_ASSERT(!HasError(), "Shouldn't call DoDecode after error!");
+
+  return mLexer.Lex(aIterator, aOnResume,
+                    [=](ICOState aState, const char* aData, size_t aLength) {
+    switch (aState) {
+      case ICOState::HEADER:
+        return ReadHeader(aData);
+      case ICOState::DIR_ENTRY:
+        return ReadDirEntry(aData);
+      case ICOState::SKIP_TO_RESOURCE:
+        return Transition::ContinueUnbuffered(ICOState::SKIP_TO_RESOURCE);
+      case ICOState::FOUND_RESOURCE:
+        return Transition::To(ICOState::SNIFF_RESOURCE, PNGSIGNATURESIZE);
+      case ICOState::SNIFF_RESOURCE:
+        return SniffResource(aData);
+      case ICOState::READ_PNG:
+        return ReadPNG(aData, aLength);
+      case ICOState::READ_BIH:
+        return ReadBIH(aData);
+      case ICOState::READ_BMP:
+        return ReadBMP(aData, aLength);
+      case ICOState::PREPARE_FOR_MASK:
+        return PrepareForMask();
+      case ICOState::READ_MASK_ROW:
+        return ReadMaskRow(aData);
+      case ICOState::FINISH_MASK:
+        return FinishMask();
+      case ICOState::SKIP_MASK:
+        return Transition::ContinueUnbuffered(ICOState::SKIP_MASK);
+      case ICOState::FINISHED_RESOURCE:
+        return FinishResource();
+      default:
+        MOZ_CRASH("Unknown ICOState");
+    }
+  });
+}
+
+bool
+nsICODecoder::WriteToContainedDecoder(const char* aBuffer, uint32_t aCount)
+{
+  MOZ_ASSERT(mContainedDecoder);
+  MOZ_ASSERT(mContainedSourceBuffer);
+
+  // Append the provided data to the SourceBuffer that the contained decoder is
+  // reading from.
+  mContainedSourceBuffer->Append(aBuffer, aCount);
+
+  bool succeeded = true;
+
+  // Write to the contained decoder. If we run out of data, the ICO decoder will
+  // get resumed when there's more data available, as usual, so we don't need
+  // the contained decoder to get resumed too. To avoid that, we provide an
+  // IResumable which just does nothing.
+  LexerResult result = mContainedDecoder->Decode();
+  if (result == LexerResult(TerminalState::FAILURE)) {
+    succeeded = false;
+  }
+
+  MOZ_ASSERT(result != LexerResult(Yield::OUTPUT_AVAILABLE),
+             "Unexpected yield");
+
+  // Make our state the same as the state of the contained decoder, and
+  // propagate errors.
+  mProgress |= mContainedDecoder->TakeProgress();
+  mInvalidRect.UnionRect(mInvalidRect, mContainedDecoder->TakeInvalidRect());
+  if (mContainedDecoder->HasError()) {
+    succeeded = false;
+  }
+
+  return succeeded;
+}
+
+} // namespace image
+} // namespace mozilla