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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 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 */
#ifndef mozilla_image_Decoder_h
#define mozilla_image_Decoder_h
#include "FrameAnimator.h"
#include "RasterImage.h"
#include "mozilla/Maybe.h"
#include "mozilla/NotNull.h"
#include "mozilla/RefPtr.h"
#include "AnimationParams.h"
#include "DecoderFlags.h"
#include "ImageMetadata.h"
#include "Orientation.h"
#include "Resolution.h"
#include "SourceBuffer.h"
#include "StreamingLexer.h"
#include "SurfaceFlags.h"
#include "qcms.h"
enum class CMSMode : int32_t;
namespace mozilla {
namespace Telemetry {
enum HistogramID : uint32_t;
} // namespace Telemetry
namespace image {
class imgFrame;
struct DecoderFinalStatus final {
DecoderFinalStatus(bool aWasMetadataDecode, bool aFinished, bool aHadError,
bool aShouldReportError)
: mWasMetadataDecode(aWasMetadataDecode),
mShouldReportError(aShouldReportError) {}
/// True if this was a metadata decode.
const bool mWasMetadataDecode : 1;
/// True if this decoder finished, whether successfully or due to failure.
const bool mFinished : 1;
/// True if this decoder encountered an error.
const bool mHadError : 1;
/// True if this decoder encountered the kind of error that should be reported
/// to the console.
const bool mShouldReportError : 1;
struct DecoderTelemetry final {
DecoderTelemetry(const Maybe<Telemetry::HistogramID>& aSpeedHistogram,
size_t aBytesDecoded, uint32_t aChunkCount,
TimeDuration aDecodeTime)
: mSpeedHistogram(aSpeedHistogram),
mDecodeTime(aDecodeTime) {}
/// @return our decoder's speed, in KBps.
int32_t Speed() const {
return mBytesDecoded / (1024 * mDecodeTime.ToSeconds());
/// @return our decoder's decode time, in microseconds.
int32_t DecodeTimeMicros() { return mDecodeTime.ToMicroseconds(); }
/// The per-image-format telemetry ID for recording our decoder's speed, or
/// Nothing() if we don't record speed telemetry for this kind of decoder.
const Maybe<Telemetry::HistogramID> mSpeedHistogram;
/// The number of bytes of input our decoder processed.
const size_t mBytesDecoded;
/// The number of chunks our decoder's input was divided into.
const uint32_t mChunkCount;
/// The amount of time our decoder spent inside DoDecode().
const TimeDuration mDecodeTime;
* Interface which owners of an animated Decoder object must implement in order
* to use recycling. It allows the decoder to get a handle to the recycled
* frames.
class IDecoderFrameRecycler {
* Request the next available recycled imgFrame from the recycler.
* @param aRecycleRect If a frame is returned, this must be set to the
* accumulated dirty rect between the frame being
* recycled, and the frame being generated.
* @returns The recycled frame, if any is available.
virtual RawAccessFrameRef RecycleFrame(gfx::IntRect& aRecycleRect) = 0;
class Decoder {
explicit Decoder(RasterImage* aImage);
* Initialize an image decoder. Decoders may not be re-initialized.
* @return NS_OK if the decoder could be initialized successfully.
nsresult Init();
* Decodes, reading all data currently available in the SourceBuffer.
* If more data is needed and @aOnResume is non-null, Decode() will schedule
* @aOnResume to be called when more data is available.
* @return a LexerResult which may indicate:
* - the image has been successfully decoded (TerminalState::SUCCESS), or
* - the image has failed to decode (TerminalState::FAILURE), or
* - the decoder is yielding until it gets more data
* (Yield::NEED_MORE_DATA), or
* - the decoder is yielding to allow the caller to access intermediate
* output (Yield::OUTPUT_AVAILABLE).
LexerResult Decode(IResumable* aOnResume = nullptr);
* Terminate this decoder in a failure state, just as if the decoder
* implementation had returned TerminalState::FAILURE from DoDecode().
* XXX(seth): This method should be removed ASAP; it exists only because
* RasterImage::FinalizeDecoder() requires an actual Decoder object as an
* argument, so we can't simply tell RasterImage a decode failed except via an
* intervening decoder. We'll fix this in bug 1291071.
LexerResult TerminateFailure();
* Given a maximum number of bytes we're willing to decode, @aByteLimit,
* returns true if we should attempt to run this decoder synchronously.
bool ShouldSyncDecode(size_t aByteLimit);
* Gets the invalidation region accumulated by the decoder so far, and clears
* the decoder's invalidation region. This means that each call to
* TakeInvalidRect() returns only the invalidation region accumulated since
* the last call to TakeInvalidRect().
OrientedIntRect TakeInvalidRect() {
OrientedIntRect invalidRect = mInvalidRect;
return invalidRect;
* Gets the progress changes accumulated by the decoder so far, and clears
* them. This means that each call to TakeProgress() returns only the changes
* accumulated since the last call to TakeProgress().
Progress TakeProgress() {
Progress progress = mProgress;
mProgress = NoProgress;
return progress;
* Returns true if there's any progress to report.
bool HasProgress() const {
return mProgress != NoProgress || !mInvalidRect.IsEmpty() ||
* State.
* If we're doing a metadata decode, we only decode the image's headers, which
* is enough to determine the image's intrinsic size. A metadata decode is
* enabled by calling SetMetadataDecode() *before* calling Init().
void SetMetadataDecode(bool aMetadataDecode) {
MOZ_ASSERT(!mInitialized, "Shouldn't be initialized yet");
mMetadataDecode = aMetadataDecode;
bool IsMetadataDecode() const { return mMetadataDecode; }
* Sets the output size of this decoder. If this is smaller than the intrinsic
* size of the image, we'll downscale it while decoding. For memory usage
* reasons, upscaling is forbidden and will trigger assertions in debug
* builds.
* Not calling SetOutputSize() means that we should just decode at the
* intrinsic size, whatever it is.
* If SetOutputSize() was called, ExplicitOutputSize() can be used to
* determine the value that was passed to it.
* This must be called before Init() is called.
void SetOutputSize(const OrientedIntSize& aSize);
* @return the output size of this decoder. If this is smaller than the
* intrinsic size, then the image will be downscaled during the decoding
* process.
* Illegal to call if HasSize() returns false.
OrientedIntSize OutputSize() const {
return *mOutputSize;
* @return either the size passed to SetOutputSize() or Nothing(), indicating
* that SetOutputSize() was not explicitly called.
Maybe<OrientedIntSize> ExplicitOutputSize() const;
* Sets the expected image size of this decoder. Decoding will fail if this
* does not match.
void SetExpectedSize(const OrientedIntSize& aSize) {
* Is the image size what was expected, if specified?
bool IsExpectedSize() const {
return mExpectedSize.isNothing() || *mExpectedSize == Size();
* Set an iterator to the SourceBuffer which will feed data to this decoder.
* This must always be called before calling Init(). (And only before Init().)
* XXX(seth): We should eliminate this method and pass a SourceBufferIterator
* to the various decoder constructors instead.
void SetIterator(SourceBufferIterator&& aIterator) {
MOZ_ASSERT(!mInitialized, "Shouldn't be initialized yet");
SourceBuffer* GetSourceBuffer() const { return mIterator->Owner(); }
* Should this decoder send partial invalidations?
bool ShouldSendPartialInvalidations() const {
return !(mDecoderFlags & DecoderFlags::IS_REDECODE);
* Should we stop decoding after the first frame?
bool IsFirstFrameDecode() const {
return bool(mDecoderFlags & DecoderFlags::FIRST_FRAME_ONLY);
* @return the number of complete animation frames which have been decoded so
* far, if it has changed since the last call to TakeCompleteFrameCount();
* otherwise, returns Nothing().
Maybe<uint32_t> TakeCompleteFrameCount();
// The number of frames we have, including anything in-progress. Thus, this
// is only 0 if we haven't begun any frames.
uint32_t GetFrameCount() { return mFrameCount; }
// Did we discover that the image we're decoding is animated?
bool HasAnimation() const { return mImageMetadata.HasAnimation(); }
// Error tracking
bool HasError() const { return mError; }
bool ShouldReportError() const { return mShouldReportError; }
// Finalize frames
void SetFinalizeFrames(bool aFinalize) { mFinalizeFrames = aFinalize; }
bool GetFinalizeFrames() const { return mFinalizeFrames; }
/// Did we finish decoding enough that calling Decode() again would be
/// useless?
bool GetDecodeDone() const {
return mReachedTerminalState || mDecodeDone ||
(mMetadataDecode && HasSize()) || HasError();
/// Are we in the middle of a frame right now? Used for assertions only.
bool InFrame() const { return mInFrame; }
/// Is the image valid if embedded inside an ICO.
virtual bool IsValidICOResource() const { return false; }
/// Type of decoder.
virtual DecoderType GetType() const { return DecoderType::UNKNOWN; }
enum DecodeStyle {
PROGRESSIVE, // produce intermediate frames representing the partial
// state of the image
SEQUENTIAL // decode to final image immediately
* Get or set the DecoderFlags that influence the behavior of this decoder.
void SetDecoderFlags(DecoderFlags aDecoderFlags) {
mDecoderFlags = aDecoderFlags;
DecoderFlags GetDecoderFlags() const { return mDecoderFlags; }
* Get or set the SurfaceFlags that select the kind of output this decoder
* will produce.
void SetSurfaceFlags(SurfaceFlags aSurfaceFlags);
SurfaceFlags GetSurfaceFlags() const { return mSurfaceFlags; }
/// @return true if we know the intrinsic size of the image we're decoding.
bool HasSize() const { return mImageMetadata.HasSize(); }
* @return the intrinsic size of the image we're decoding.
* Illegal to call if HasSize() returns false.
OrientedIntSize Size() const {
return mImageMetadata.GetSize();
* @return an IntRect which covers the entire area of this image at its
* intrinsic size, appropriate for use as a frame rect when the image itself
* does not specify one.
* Illegal to call if HasSize() returns false.
OrientedIntRect FullFrame() const {
return OrientedIntRect(OrientedIntPoint(), Size());
* @return an IntRect which covers the entire area of this image at its size
* after scaling - that is, at its output size.
* XXX(seth): This is only used for decoders which are using the old
* Downscaler code instead of SurfacePipe, since the old AllocateFrame() and
* Downscaler APIs required that the frame rect be specified in output space.
* We should remove this once all decoders use SurfacePipe.
* Illegal to call if HasSize() returns false.
OrientedIntRect FullOutputFrame() const {
return OrientedIntRect(OrientedIntPoint(), OutputSize());
* @return the orientation of the image.
* Illegal to call if HasSize() returns false.
Orientation GetOrientation() const {
return mImageMetadata.GetOrientation();
/// @return final status information about this decoder. Should be called
/// after we decide we're not going to run the decoder anymore.
DecoderFinalStatus FinalStatus() const;
/// @return the metadata we collected about this image while decoding.
const ImageMetadata& GetImageMetadata() { return mImageMetadata; }
/// @return performance telemetry we collected while decoding.
DecoderTelemetry Telemetry() const;
* @return a weak pointer to the image associated with this decoder. Illegal
* to call if this decoder is not associated with an image.
NotNull<RasterImage*> GetImage() const { return WrapNotNull(mImage.get()); }
* @return a possibly-null weak pointer to the image associated with this
* decoder. May be called even if this decoder is not associated with an
* image.
RasterImage* GetImageMaybeNull() const { return mImage.get(); }
RawAccessFrameRef GetCurrentFrameRef() {
return mCurrentFrame ? mCurrentFrame->RawAccessRef() : RawAccessFrameRef();
* For use during decoding only. Allows the BlendAnimationFilter to get the
* current frame we are producing for its animation parameters.
imgFrame* GetCurrentFrame() { return mCurrentFrame.get(); }
* For use during decoding only. Allows the BlendAnimationFilter to get the
* frame it should be pulling the previous frame data from.
const RawAccessFrameRef& GetRestoreFrameRef() const { return mRestoreFrame; }
const gfx::IntRect& GetRestoreDirtyRect() const { return mRestoreDirtyRect; }
const gfx::IntRect& GetRecycleRect() const { return mRecycleRect; }
const gfx::IntRect& GetFirstFrameRefreshArea() const {
return mFirstFrameRefreshArea;
bool HasFrameToTake() const { return mHasFrameToTake; }
void ClearHasFrameToTake() {
mHasFrameToTake = false;
IDecoderFrameRecycler* GetFrameRecycler() const { return mFrameRecycler; }
void SetFrameRecycler(IDecoderFrameRecycler* aFrameRecycler) {
mFrameRecycler = aFrameRecycler;
friend class AutoRecordDecoderTelemetry;
friend class DecoderTestHelper;
friend class nsBMPDecoder;
friend class nsICODecoder;
friend class ReorientSurfaceSink;
friend class SurfaceSink;
virtual ~Decoder();
* Internal hooks. Decoder implementations may override these and
* only these methods.
* BeforeFinishInternal() can be used to detect if decoding is in an
* incomplete state, e.g. due to file truncation, in which case it should
* return a failing nsresult.
virtual nsresult InitInternal();
virtual LexerResult DoDecode(SourceBufferIterator& aIterator,
IResumable* aOnResume) = 0;
virtual nsresult BeforeFinishInternal();
virtual nsresult FinishInternal();
virtual nsresult FinishWithErrorInternal();
qcms_profile* GetCMSOutputProfile() const;
qcms_transform* GetCMSsRGBTransform(gfx::SurfaceFormat aFormat) const;
* @return the per-image-format telemetry ID for recording this decoder's
* speed, or Nothing() if we don't record speed telemetry for this kind of
* decoder.
virtual Maybe<Telemetry::HistogramID> SpeedHistogram() const {
return Nothing();
* Progress notifications.
// Called by decoders when they determine the size of the image. Informs
// the image of its size and sends notifications.
void PostSize(int32_t aWidth, int32_t aHeight, Orientation = Orientation(),
Resolution = Resolution());
// Called by decoders if they determine that the image has transparency.
// This should be fired as early as possible to allow observers to do things
// that affect content, so it's necessarily pessimistic - if there's a
// possibility that the image has transparency, for example because its header
// specifies that it has an alpha channel, we fire PostHasTransparency
// immediately. PostFrameStop's aFrameOpacity argument, on the other hand, is
// only used internally to ImageLib. Because PostFrameStop isn't delivered
// until the entire frame has been decoded, decoders may take into account the
// actual contents of the frame and give a more accurate result.
void PostHasTransparency();
// Called by decoders if they determine that the image is animated.
// @param aTimeout The time for which the first frame should be shown before
// we advance to the next frame.
void PostIsAnimated(FrameTimeout aFirstFrameTimeout);
// Called by decoders when they end a frame. Informs the image, sends
// notifications, and does internal book-keeping.
// Specify whether this frame is opaque as an optimization.
// For animated images, specify the disposal, blend method and timeout for
// this frame.
void PostFrameStop(Opacity aFrameOpacity = Opacity::SOME_TRANSPARENCY);
* Called by the decoders when they have a region to invalidate. We may not
* actually pass these invalidations on right away.
* @param aRect The invalidation rect in the coordinate system of the unscaled
* image (that is, the image at its intrinsic size).
* @param aRectAtOutputSize If not Nothing(), the invalidation rect in the
* coordinate system of the scaled image (that is,
* the image at our output size). This must
* be supplied if we're downscaling during decode.
void PostInvalidation(
const OrientedIntRect& aRect,
const Maybe<OrientedIntRect>& aRectAtOutputSize = Nothing());
// Called by the decoders when they have successfully decoded the image. This
// may occur as the result of the decoder getting to the appropriate point in
// the stream, or by us calling FinishInternal().
// May not be called mid-frame.
// For animated images, specify the loop count. -1 means loop forever, 0
// means a single iteration, stopping on the last frame.
void PostDecodeDone(int32_t aLoopCount = 0);
* Allocates a new frame, making it our current frame if successful.
nsresult AllocateFrame(const gfx::IntSize& aOutputSize,
gfx::SurfaceFormat aFormat,
const Maybe<AnimationParams>& aAnimParams = Nothing());
/// Report that an error was encountered while decoding.
void PostError();
* CompleteDecode() finishes up the decoding process after Decode() determines
* that we're finished. It records final progress and does all the cleanup
* that's possible off-main-thread.
void CompleteDecode();
/// @return the number of complete frames we have. Does not include the
/// current frame if it's unfinished.
uint32_t GetCompleteFrameCount() {
if (mFrameCount == 0) {
return 0;
return mInFrame ? mFrameCount - 1 : mFrameCount;
RawAccessFrameRef AllocateFrameInternal(
const gfx::IntSize& aOutputSize, gfx::SurfaceFormat aFormat,
const Maybe<AnimationParams>& aAnimParams,
RawAccessFrameRef&& aPreviousFrame);
/// Color management profile from the ICCP chunk in the image.
qcms_profile* mInProfile;
/// Color management transform to apply to image data.
qcms_transform* mTransform;
uint8_t* mImageData; // Pointer to image data in BGRA/X
uint32_t mImageDataLength;
CMSMode mCMSMode;
RefPtr<RasterImage> mImage;
Maybe<SourceBufferIterator> mIterator;
IDecoderFrameRecycler* mFrameRecycler;
// The current frame the decoder is producing.
RawAccessFrameRef mCurrentFrame;
// The complete frame to combine with the current partial frame to produce
// a complete current frame.
RawAccessFrameRef mRestoreFrame;
ImageMetadata mImageMetadata;
mInvalidRect; // Tracks new rows as the current frame is decoded.
gfx::IntRect mRestoreDirtyRect; // Tracks an invalidation region between the
// restore frame and the previous frame.
gfx::IntRect mRecycleRect; // Tracks an invalidation region between the
// recycled frame and the current frame.
Maybe<OrientedIntSize> mOutputSize; // The size of our output surface.
Maybe<OrientedIntSize> mExpectedSize; // The expected size of the image.
Progress mProgress;
uint32_t mFrameCount; // Number of frames, including anything in-progress
FrameTimeout mLoopLength; // Length of a single loop of this image.
mFirstFrameRefreshArea; // The area of the image that needs to
// be invalidated when the animation loops.
// Telemetry data for this decoder.
TimeDuration mDecodeTime;
DecoderFlags mDecoderFlags;
SurfaceFlags mSurfaceFlags;
bool mInitialized : 1;
bool mMetadataDecode : 1;
bool mHaveExplicitOutputSize : 1;
bool mInFrame : 1;
bool mFinishedNewFrame : 1; // True if PostFrameStop() has been called since
// the last call to TakeCompleteFrameCount().
// Has a new frame that AnimationSurfaceProvider can take. Unfortunately this
// has to be separate from mFinishedNewFrame because the png decoder yields a
// new frame before calling PostFrameStop().
bool mHasFrameToTake : 1;
bool mReachedTerminalState : 1;
bool mDecodeDone : 1;
bool mError : 1;
bool mShouldReportError : 1;
bool mFinalizeFrames : 1;
} // namespace image
} // namespace mozilla
#endif // mozilla_image_Decoder_h