gecko-dev/dom/media/CanvasCaptureMediaStream.cpp

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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 http://mozilla.org/MPL/2.0/. */
#include "CanvasCaptureMediaStream.h"
#include "DOMMediaStream.h"
#include "gfxPlatform.h"
#include "ImageContainer.h"
#include "MediaStreamGraph.h"
#include "mozilla/dom/CanvasCaptureMediaStreamBinding.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/Atomics.h"
#include "nsContentUtils.h"
using namespace mozilla::layers;
using namespace mozilla::gfx;
namespace mozilla {
namespace dom {
class OutputStreamDriver::StreamListener : public MediaStreamListener
{
public:
explicit StreamListener(OutputStreamDriver* aDriver,
TrackID aTrackId,
SourceMediaStream* aSourceStream)
: mEnded(false)
, mSourceStream(aSourceStream)
, mTrackId(aTrackId)
, mMutex("CanvasCaptureMediaStream OutputStreamDriver::StreamListener")
, mImage(nullptr)
{
MOZ_ASSERT(mSourceStream);
}
void EndStream() {
mEnded = true;
}
void SetImage(const RefPtr<layers::Image>& aImage)
{
MutexAutoLock lock(mMutex);
mImage = aImage;
}
virtual void NotifyPull(MediaStreamGraph* aGraph, StreamTime aDesiredTime) override
{
// Called on the MediaStreamGraph thread.
StreamTime delta = aDesiredTime - mSourceStream->GetEndOfAppendedData(mTrackId);
if (delta > 0) {
MutexAutoLock lock(mMutex);
MOZ_ASSERT(mSourceStream);
RefPtr<Image> image = mImage;
IntSize size = image ? image->GetSize() : IntSize(0, 0);
VideoSegment segment;
segment.AppendFrame(image.forget(), delta, size);
mSourceStream->AppendToTrack(mTrackId, &segment);
}
if (mEnded) {
mSourceStream->EndAllTrackAndFinish();
}
}
protected:
~StreamListener() { }
private:
Atomic<bool> mEnded;
const RefPtr<SourceMediaStream> mSourceStream;
const TrackID mTrackId;
Mutex mMutex;
// The below members are protected by mMutex.
RefPtr<layers::Image> mImage;
};
OutputStreamDriver::OutputStreamDriver(SourceMediaStream* aSourceStream,
const TrackID& aTrackId)
: FrameCaptureListener()
, mSourceStream(aSourceStream)
, mStreamListener(new StreamListener(this, aTrackId, aSourceStream))
{
MOZ_ASSERT(NS_IsMainThread());
MOZ_ASSERT(mSourceStream);
mSourceStream->AddListener(mStreamListener);
mSourceStream->AddTrack(aTrackId, 0, new VideoSegment());
mSourceStream->AdvanceKnownTracksTime(STREAM_TIME_MAX);
mSourceStream->SetPullEnabled(true);
// All CanvasCaptureMediaStreams shall at least get one frame.
mFrameCaptureRequested = true;
}
OutputStreamDriver::~OutputStreamDriver()
{
MOZ_ASSERT(NS_IsMainThread());
if (mStreamListener) {
// MediaStreamGraph will keep the listener alive until it can finish the
// stream on the next NotifyPull().
mStreamListener->EndStream();
}
}
void
OutputStreamDriver::SetImage(const RefPtr<layers::Image>& aImage)
{
if (mStreamListener) {
mStreamListener->SetImage(aImage);
}
}
// ----------------------------------------------------------------------
class TimerDriver : public OutputStreamDriver
{
public:
explicit TimerDriver(SourceMediaStream* aSourceStream,
const double& aFPS,
const TrackID& aTrackId)
: OutputStreamDriver(aSourceStream, aTrackId)
, mFPS(aFPS)
, mTimer(nullptr)
{
if (mFPS == 0.0) {
return;
}
mTimer = do_CreateInstance(NS_TIMER_CONTRACTID);
if (!mTimer) {
return;
}
mTimer->InitWithFuncCallback(&TimerTick, this, int(1000 / mFPS), nsITimer::TYPE_REPEATING_SLACK);
}
static void TimerTick(nsITimer* aTimer, void* aClosure)
{
MOZ_ASSERT(aClosure);
TimerDriver* driver = static_cast<TimerDriver*>(aClosure);
driver->RequestFrameCapture();
}
void NewFrame(already_AddRefed<Image> aImage) override
{
RefPtr<Image> image = aImage;
if (!mFrameCaptureRequested) {
return;
}
mFrameCaptureRequested = false;
SetImage(image.forget());
}
void Forget() override
{
if (mTimer) {
mTimer->Cancel();
mTimer = nullptr;
}
}
protected:
virtual ~TimerDriver() {}
private:
const double mFPS;
nsCOMPtr<nsITimer> mTimer;
};
// ----------------------------------------------------------------------
class AutoDriver : public OutputStreamDriver
{
public:
explicit AutoDriver(SourceMediaStream* aSourceStream,
const TrackID& aTrackId)
: OutputStreamDriver(aSourceStream, aTrackId) {}
void NewFrame(already_AddRefed<Image> aImage) override
{
// Don't reset `mFrameCaptureRequested` since AutoDriver shall always have
// `mFrameCaptureRequested` set to true.
// This also means we should accept every frame as NewFrame is called only
// after something changed.
RefPtr<Image> image = aImage;
SetImage(image.forget());
}
protected:
virtual ~AutoDriver() {}
};
// ----------------------------------------------------------------------
NS_IMPL_CYCLE_COLLECTION_INHERITED(CanvasCaptureMediaStream, DOMMediaStream,
mCanvas)
NS_IMPL_ADDREF_INHERITED(CanvasCaptureMediaStream, DOMMediaStream)
NS_IMPL_RELEASE_INHERITED(CanvasCaptureMediaStream, DOMMediaStream)
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(CanvasCaptureMediaStream)
NS_INTERFACE_MAP_END_INHERITING(DOMMediaStream)
CanvasCaptureMediaStream::CanvasCaptureMediaStream(HTMLCanvasElement* aCanvas)
: mCanvas(aCanvas)
, mOutputStreamDriver(nullptr)
{
}
CanvasCaptureMediaStream::~CanvasCaptureMediaStream()
{
if (mOutputStreamDriver) {
mOutputStreamDriver->Forget();
}
}
JSObject*
CanvasCaptureMediaStream::WrapObject(JSContext* aCx, JS::Handle<JSObject*> aGivenProto)
{
return dom::CanvasCaptureMediaStreamBinding::Wrap(aCx, this, aGivenProto);
}
void
CanvasCaptureMediaStream::RequestFrame()
{
MOZ_ASSERT(mOutputStreamDriver);
if (mOutputStreamDriver) {
mOutputStreamDriver->RequestFrameCapture();
}
}
nsresult
CanvasCaptureMediaStream::Init(const dom::Optional<double>& aFPS,
const TrackID& aTrackId)
{
if (!aFPS.WasPassed()) {
mOutputStreamDriver =
new AutoDriver(GetInputStream()->AsSourceStream(), aTrackId);
} else if (aFPS.Value() < 0) {
return NS_ERROR_ILLEGAL_VALUE;
} else {
// Cap frame rate to 60 FPS for sanity
double fps = std::min(60.0, aFPS.Value());
mOutputStreamDriver =
new TimerDriver(GetInputStream()->AsSourceStream(), fps, aTrackId);
}
return NS_OK;
}
already_AddRefed<CanvasCaptureMediaStream>
CanvasCaptureMediaStream::CreateSourceStream(nsIDOMWindow* aWindow,
HTMLCanvasElement* aCanvas)
{
RefPtr<CanvasCaptureMediaStream> stream = new CanvasCaptureMediaStream(aCanvas);
MediaStreamGraph* graph =
MediaStreamGraph::GetInstance(MediaStreamGraph::SYSTEM_THREAD_DRIVER,
AudioChannel::Normal);
stream->InitSourceStream(aWindow, graph);
return stream.forget();
}
FrameCaptureListener*
CanvasCaptureMediaStream::FrameCaptureListener()
{
return mOutputStreamDriver;
}
} // namespace dom
} // namespace mozilla