gecko-dev/image/IDecodingTask.h
Andrew Osmond 414919edbf Bug 1503935 - Fix some WebP decoder implementation bugs. r=tnikkel
First we did not handle the SourceBufferIterator::WAITING state which
can happen when we get woken up but there is no data to read from the
SourceBufferIterator. StreamingLexer handled this properly by yielding
with NEED_MORE_DATA, and properly scheduling the decoder to resume. This
patch does the same in the WebP decoder.

Second nsWebPDecoder::GetType was not implemented. This meant it would
return DecoderType::UNKNOWN, and would fail to recreate the decoder if
we are discarding frames and need to restart from the beginning. In
addition to implementing that method, this patch also corrects an assert
in DecoderFactory::CloneAnimationDecoder which failed to check for WebP
as a supported animated decoder.

This patch also modestly improves the logging output and library method
checks.

Differential Revision: https://phabricator.services.mozilla.com/D10624
2018-11-01 19:26:14 -04:00

133 lines
3.5 KiB
C++

/* -*- 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 http://mozilla.org/MPL/2.0/. */
/**
* An interface for tasks which can execute on the ImageLib DecodePool, and
* various implementations.
*/
#ifndef mozilla_image_IDecodingTask_h
#define mozilla_image_IDecodingTask_h
#include "imgFrame.h"
#include "mozilla/NotNull.h"
#include "mozilla/RefPtr.h"
#include "nsIEventTarget.h"
#include "SourceBuffer.h"
namespace mozilla {
namespace image {
class Decoder;
class RasterImage;
/// A priority hint that DecodePool can use when scheduling an IDecodingTask.
enum class TaskPriority : uint8_t
{
eLow,
eHigh
};
/**
* An interface for tasks which can execute on the ImageLib DecodePool.
*/
class IDecodingTask : public IResumable
{
public:
/// Run the task.
virtual void Run() = 0;
/// @return true if, given the option, this task prefers to run synchronously.
virtual bool ShouldPreferSyncRun() const = 0;
/// @return a priority hint that DecodePool can use when scheduling this task.
virtual TaskPriority Priority() const = 0;
/// A default implementation of IResumable which resubmits the task to the
/// DecodePool. Subclasses can override this if they need different behavior.
void Resume() override;
protected:
virtual ~IDecodingTask() { }
/// Notify @aImage of @aDecoder's progress.
void NotifyProgress(NotNull<RasterImage*> aImage,
NotNull<Decoder*> aDecoder);
/// Notify @aImage that @aDecoder has finished.
void NotifyDecodeComplete(NotNull<RasterImage*> aImage,
NotNull<Decoder*> aDecoder);
private:
void EnsureHasEventTarget(NotNull<RasterImage*> aImage);
bool IsOnEventTarget() const;
nsCOMPtr<nsIEventTarget> mEventTarget;
};
/**
* An IDecodingTask implementation for metadata decodes of images.
*/
class MetadataDecodingTask final : public IDecodingTask
{
public:
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(MetadataDecodingTask, override)
explicit MetadataDecodingTask(NotNull<Decoder*> aDecoder);
void Run() override;
// Metadata decodes are very fast (since they only need to examine an image's
// header) so there's no reason to refuse to run them synchronously if the
// caller will allow us to.
bool ShouldPreferSyncRun() const override { return true; }
// Metadata decodes run at the highest priority because they block layout and
// page load.
TaskPriority Priority() const override { return TaskPriority::eHigh; }
private:
virtual ~MetadataDecodingTask() { }
/// Mutex protecting access to mDecoder.
Mutex mMutex;
NotNull<RefPtr<Decoder>> mDecoder;
};
/**
* An IDecodingTask implementation for anonymous decoders - that is, decoders
* with no associated Image object.
*/
class AnonymousDecodingTask final : public IDecodingTask
{
public:
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(AnonymousDecodingTask, override)
explicit AnonymousDecodingTask(NotNull<Decoder*> aDecoder,
bool aResumable);
void Run() override;
bool ShouldPreferSyncRun() const override { return true; }
TaskPriority Priority() const override { return TaskPriority::eLow; }
void Resume() override;
private:
virtual ~AnonymousDecodingTask() { }
NotNull<RefPtr<Decoder>> mDecoder;
bool mResumable;
};
} // namespace image
} // namespace mozilla
#endif // mozilla_image_IDecodingTask_h