HTMLCanvasElement.cpp
/* -*- 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 "mozilla/dom/HTMLCanvasElement.h"
#include "ImageEncoder.h"
#include "jsapi.h"
#include "jsfriendapi.h"
#include "MediaTrackGraph.h"
#include "mozilla/Assertions.h"
#include "mozilla/Base64.h"
#include "mozilla/BasePrincipal.h"
#include "mozilla/CheckedInt.h"
#include "mozilla/PresShell.h"
#include "mozilla/dom/CanvasCaptureMediaStream.h"
#include "mozilla/dom/CanvasRenderingContext2D.h"
#include "mozilla/dom/Document.h"
#include "mozilla/dom/GeneratePlaceholderCanvasData.h"
#include "mozilla/dom/Event.h"
#include "mozilla/dom/File.h"
#include "mozilla/dom/HTMLCanvasElementBinding.h"
#include "mozilla/dom/VideoStreamTrack.h"
#include "mozilla/dom/MouseEvent.h"
#include "mozilla/dom/OffscreenCanvas.h"
#include "mozilla/dom/OffscreenCanvasDisplayHelper.h"
#include "mozilla/EventDispatcher.h"
#include "mozilla/gfx/Rect.h"
#include "mozilla/layers/CanvasRenderer.h"
#include "mozilla/layers/WebRenderCanvasRenderer.h"
#include "mozilla/layers/WebRenderUserData.h"
#include "mozilla/MouseEvents.h"
#include "mozilla/Preferences.h"
#include "mozilla/ProfilerLabels.h"
#include "mozilla/StaticPrefs_privacy.h"
#include "mozilla/Telemetry.h"
#include "mozilla/webgpu/CanvasContext.h"
#include "nsAttrValueInlines.h"
#include "nsContentUtils.h"
#include "nsDisplayList.h"
#include "nsDOMJSUtils.h"
#include "nsITimer.h"
#include "nsJSUtils.h"
#include "nsLayoutUtils.h"
#include "nsMathUtils.h"
#include "nsNetUtil.h"
#include "nsRefreshDriver.h"
#include "nsStreamUtils.h"
#include "ActiveLayerTracker.h"
#include "CanvasUtils.h"
#include "VRManagerChild.h"
#include "ClientWebGLContext.h"
#include "WindowRenderer.h"
using namespace mozilla::layers;
using namespace mozilla::gfx;
NS_IMPL_NS_NEW_HTML_ELEMENT(Canvas)
namespace mozilla::dom {
class RequestedFrameRefreshObserver : public nsARefreshObserver {
NS_INLINE_DECL_THREADSAFE_REFCOUNTING(RequestedFrameRefreshObserver, override)
public:
RequestedFrameRefreshObserver(HTMLCanvasElement* const aOwningElement,
nsRefreshDriver* aRefreshDriver,
bool aReturnPlaceholderData)
: mRegistered(false),
mReturnPlaceholderData(aReturnPlaceholderData),
mOwningElement(aOwningElement),
mRefreshDriver(aRefreshDriver),
mWatchManager(this, AbstractThread::MainThread()),
mPendingThrottledCapture(false) {
MOZ_ASSERT(mOwningElement);
}
static already_AddRefed<DataSourceSurface> CopySurface(
const RefPtr<SourceSurface>& aSurface, bool aReturnPlaceholderData) {
RefPtr<DataSourceSurface> data = aSurface->GetDataSurface();
if (!data) {
return nullptr;
}
DataSourceSurface::ScopedMap read(data, DataSourceSurface::READ);
if (!read.IsMapped()) {
return nullptr;
}
RefPtr<DataSourceSurface> copy = Factory::CreateDataSourceSurfaceWithStride(
data->GetSize(), data->GetFormat(), read.GetStride());
if (!copy) {
return nullptr;
}
DataSourceSurface::ScopedMap write(copy, DataSourceSurface::WRITE);
if (!write.IsMapped()) {
return nullptr;
}
MOZ_ASSERT(read.GetStride() == write.GetStride());
MOZ_ASSERT(data->GetSize() == copy->GetSize());
MOZ_ASSERT(data->GetFormat() == copy->GetFormat());
if (aReturnPlaceholderData) {
auto size = write.GetStride() * copy->GetSize().height;
auto* data = write.GetData();
GeneratePlaceholderCanvasData(size, data);
} else {
memcpy(write.GetData(), read.GetData(),
write.GetStride() * copy->GetSize().height);
}
return copy.forget();
}
void SetReturnPlaceholderData(bool aReturnPlaceholderData) {
mReturnPlaceholderData = aReturnPlaceholderData;
}
void NotifyCaptureStateChange() {
if (mPendingThrottledCapture) {
return;
}
if (!mOwningElement) {
return;
}
Watchable<FrameCaptureState>* captureState =
mOwningElement->GetFrameCaptureState();
if (!captureState) {
PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
"Abort: No capture state"_ns);
return;
}
if (captureState->Ref() == FrameCaptureState::CLEAN) {
PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
"Abort: CLEAN"_ns);
return;
}
if (!mRefreshDriver) {
PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
"Abort: no refresh driver"_ns);
return;
}
if (!mRefreshDriver->IsThrottled()) {
PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
"Abort: not throttled"_ns);
return;
}
TimeStamp now = TimeStamp::Now();
TimeStamp next =
mLastCaptureTime.IsNull()
? now
: mLastCaptureTime + TimeDuration::FromMilliseconds(
nsRefreshDriver::DefaultInterval());
if (mLastCaptureTime.IsNull() || next <= now) {
AUTO_PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
"CaptureFrame direct while throttled"_ns);
CaptureFrame(now);
return;
}
nsCString str;
if (profiler_thread_is_being_profiled_for_markers()) {
str.AppendPrintf("Delaying CaptureFrame by %.2fms",
(next - now).ToMilliseconds());
}
AUTO_PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {}, str);
mPendingThrottledCapture = true;
AbstractThread::MainThread()->DelayedDispatch(
NS_NewRunnableFunction(
__func__,
[this, self = RefPtr<RequestedFrameRefreshObserver>(this), next] {
mPendingThrottledCapture = false;
AUTO_PROFILER_MARKER_TEXT(
"Canvas CaptureStream", MEDIA_RT, {},
"CaptureFrame after delay while throttled"_ns);
CaptureFrame(next);
}),
// next >= now, so this is a guard for (next - now) flooring to 0.
std::max<uint32_t>(
1, static_cast<uint32_t>((next - now).ToMilliseconds())));
}
void WillRefresh(TimeStamp aTime) override {
AUTO_PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
"CaptureFrame by refresh driver"_ns);
CaptureFrame(aTime);
}
void CaptureFrame(TimeStamp aTime) {
MOZ_ASSERT(NS_IsMainThread());
if (!mOwningElement) {
PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
"Abort: no owning element"_ns);
return;
}
if (mOwningElement->IsWriteOnly()) {
PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
"Abort: write only"_ns);
return;
}
if (auto* captureStateWatchable = mOwningElement->GetFrameCaptureState();
captureStateWatchable &&
*captureStateWatchable == FrameCaptureState::CLEAN) {
PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
"Abort: CLEAN"_ns);
return;
}
// Mark the context already now, since if the frame capture state is DIRTY
// and we catch an early return below (not marking it CLEAN), the next draw
// will not trigger a capture state change from the
// Watchable<FrameCaptureState>.
mOwningElement->MarkContextCleanForFrameCapture();
mOwningElement->ProcessDestroyedFrameListeners();
if (!mOwningElement->IsFrameCaptureRequested(aTime)) {
PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
"Abort: no capture requested"_ns);
return;
}
RefPtr<SourceSurface> snapshot;
{
AUTO_PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
"GetSnapshot"_ns);
snapshot = mOwningElement->GetSurfaceSnapshot(nullptr);
if (!snapshot) {
PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
"Abort: snapshot failed"_ns);
return;
}
}
RefPtr<DataSourceSurface> copy;
{
AUTO_PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
"CopySurface"_ns);
copy = CopySurface(snapshot, mReturnPlaceholderData);
if (!copy) {
PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {},
"Abort: copy failed"_ns);
return;
}
}
nsCString str;
if (profiler_thread_is_being_profiled_for_markers()) {
TimeDuration sinceLast =
aTime - (mLastCaptureTime.IsNull() ? aTime : mLastCaptureTime);
str.AppendPrintf("Forwarding captured frame %.2fms after last",
sinceLast.ToMilliseconds());
}
AUTO_PROFILER_MARKER_TEXT("Canvas CaptureStream", MEDIA_RT, {}, str);
if (!mLastCaptureTime.IsNull() && aTime <= mLastCaptureTime) {
aTime = mLastCaptureTime + TimeDuration::FromMilliseconds(1);
}
mLastCaptureTime = aTime;
mOwningElement->SetFrameCapture(copy.forget(), aTime);
}
void DetachFromRefreshDriver() {
MOZ_ASSERT(mOwningElement);
MOZ_ASSERT(mRefreshDriver);
Unregister();
mRefreshDriver = nullptr;
mWatchManager.Shutdown();
}
void Register() {
if (mRegistered) {
return;
}
MOZ_ASSERT(mRefreshDriver);
if (mRefreshDriver) {
mRefreshDriver->AddRefreshObserver(this, FlushType::Display,
"Canvas frame capture listeners");
mRegistered = true;
}
if (!mOwningElement) {
return;
}
if (Watchable<FrameCaptureState>* captureState =
mOwningElement->GetFrameCaptureState()) {
mWatchManager.Watch(
*captureState,
&RequestedFrameRefreshObserver::NotifyCaptureStateChange);
}
}
void Unregister() {
if (!mRegistered) {
return;
}
MOZ_ASSERT(mRefreshDriver);
if (mRefreshDriver) {
mRefreshDriver->RemoveRefreshObserver(this, FlushType::Display);
mRegistered = false;
}
if (!mOwningElement) {
return;
}
if (Watchable<FrameCaptureState>* captureState =
mOwningElement->GetFrameCaptureState()) {
mWatchManager.Unwatch(
*captureState,
&RequestedFrameRefreshObserver::NotifyCaptureStateChange);
}
}
private:
virtual ~RequestedFrameRefreshObserver() {
MOZ_ASSERT(!mRefreshDriver);
MOZ_ASSERT(!mRegistered);
}
bool mRegistered;
bool mReturnPlaceholderData;
const WeakPtr<HTMLCanvasElement> mOwningElement;
RefPtr<nsRefreshDriver> mRefreshDriver;
WatchManager<RequestedFrameRefreshObserver> mWatchManager;
TimeStamp mLastCaptureTime;
bool mPendingThrottledCapture;
};
// ---------------------------------------------------------------------------
NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(HTMLCanvasPrintState, mCanvas, mContext,
mCallback)
HTMLCanvasPrintState::HTMLCanvasPrintState(
HTMLCanvasElement* aCanvas, nsICanvasRenderingContextInternal* aContext,
nsITimerCallback* aCallback)
: mIsDone(false),
mPendingNotify(false),
mCanvas(aCanvas),
mContext(aContext),
mCallback(aCallback) {}
HTMLCanvasPrintState::~HTMLCanvasPrintState() = default;
/* virtual */
JSObject* HTMLCanvasPrintState::WrapObject(JSContext* aCx,
JS::Handle<JSObject*> aGivenProto) {
return MozCanvasPrintState_Binding::Wrap(aCx, this, aGivenProto);
}
nsISupports* HTMLCanvasPrintState::Context() const { return mContext; }
void HTMLCanvasPrintState::Done() {
if (!mPendingNotify && !mIsDone) {
// The canvas needs to be invalidated for printing reftests on linux to
// work.
if (mCanvas) {
mCanvas->InvalidateCanvas();
}
RefPtr<nsRunnableMethod<HTMLCanvasPrintState>> doneEvent =
NewRunnableMethod("dom::HTMLCanvasPrintState::NotifyDone", this,
&HTMLCanvasPrintState::NotifyDone);
if (NS_SUCCEEDED(NS_DispatchToCurrentThread(doneEvent))) {
mPendingNotify = true;
}
}
}
void HTMLCanvasPrintState::NotifyDone() {
mIsDone = true;
mPendingNotify = false;
if (mCallback) {
mCallback->Notify(nullptr);
}
}
// ---------------------------------------------------------------------------
HTMLCanvasElementObserver::HTMLCanvasElementObserver(
HTMLCanvasElement* aElement)
: mElement(aElement) {
RegisterObserverEvents();
}
HTMLCanvasElementObserver::~HTMLCanvasElementObserver() { Destroy(); }
void HTMLCanvasElementObserver::Destroy() {
UnregisterObserverEvents();
mElement = nullptr;
}
void HTMLCanvasElementObserver::RegisterObserverEvents() {
if (!mElement) {
return;
}
nsCOMPtr<nsIObserverService> observerService =
mozilla::services::GetObserverService();
MOZ_ASSERT(observerService);
if (observerService) {
observerService->AddObserver(this, "memory-pressure", false);
observerService->AddObserver(this, "canvas-device-reset", false);
}
}
void HTMLCanvasElementObserver::UnregisterObserverEvents() {
if (!mElement) {
return;
}
nsCOMPtr<nsIObserverService> observerService =
mozilla::services::GetObserverService();
// Do not assert on observerService here. This might be triggered by
// the cycle collector at a late enough time, that XPCOM services are
// no longer available. See bug 1029504.
if (observerService) {
observerService->RemoveObserver(this, "memory-pressure");
observerService->RemoveObserver(this, "canvas-device-reset");
}
}
NS_IMETHODIMP
HTMLCanvasElementObserver::Observe(nsISupports*, const char* aTopic,
const char16_t*) {
if (!mElement) {
return NS_OK;
}
if (strcmp(aTopic, "memory-pressure") == 0) {
mElement->OnMemoryPressure();
} else if (strcmp(aTopic, "canvas-device-reset") == 0) {
mElement->OnDeviceReset();
}
return NS_OK;
}
NS_IMPL_ISUPPORTS(HTMLCanvasElementObserver, nsIObserver)
// ---------------------------------------------------------------------------
HTMLCanvasElement::HTMLCanvasElement(
already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo)
: nsGenericHTMLElement(std::move(aNodeInfo)),
mResetLayer(true),
mMaybeModified(false),
mWriteOnly(false) {}
HTMLCanvasElement::~HTMLCanvasElement() { Destroy(); }
void HTMLCanvasElement::Destroy() {
if (mOffscreenDisplay) {
mOffscreenDisplay->DestroyElement();
mOffscreenDisplay = nullptr;
mImageContainer = nullptr;
}
if (mContextObserver) {
mContextObserver->Destroy();
mContextObserver = nullptr;
}
ResetPrintCallback();
if (mRequestedFrameRefreshObserver) {
mRequestedFrameRefreshObserver->DetachFromRefreshDriver();
mRequestedFrameRefreshObserver = nullptr;
}
}
NS_IMPL_CYCLE_COLLECTION_CLASS(HTMLCanvasElement)
NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN_INHERITED(HTMLCanvasElement,
nsGenericHTMLElement)
tmp->Destroy();
NS_IMPL_CYCLE_COLLECTION_UNLINK(mCurrentContext, mPrintCallback, mPrintState,
mOriginalCanvas, mOffscreenCanvas)
NS_IMPL_CYCLE_COLLECTION_UNLINK_END
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(HTMLCanvasElement,
nsGenericHTMLElement)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mCurrentContext, mPrintCallback,
mPrintState, mOriginalCanvas,
mOffscreenCanvas)
NS_IMPL_CYCLE_COLLECTION_TRAVERSE_END
NS_IMPL_ISUPPORTS_CYCLE_COLLECTION_INHERITED_0(HTMLCanvasElement,
nsGenericHTMLElement)
NS_IMPL_ELEMENT_CLONE(HTMLCanvasElement)
/* virtual */
JSObject* HTMLCanvasElement::WrapNode(JSContext* aCx,
JS::Handle<JSObject*> aGivenProto) {
return HTMLCanvasElement_Binding::Wrap(aCx, this, aGivenProto);
}
already_AddRefed<nsICanvasRenderingContextInternal>
HTMLCanvasElement::CreateContext(CanvasContextType aContextType) {
// Note that the compositor backend will be LAYERS_NONE if there is no widget.
RefPtr<nsICanvasRenderingContextInternal> ret =
CreateContextHelper(aContextType, GetCompositorBackendType());
// Add Observer for webgl canvas.
if (aContextType == CanvasContextType::WebGL1 ||
aContextType == CanvasContextType::WebGL2 ||
aContextType == CanvasContextType::Canvas2D) {
if (!mContextObserver) {
mContextObserver = new HTMLCanvasElementObserver(this);
}
}
ret->SetCanvasElement(this);
return ret.forget();
}
nsIntSize HTMLCanvasElement::GetWidthHeight() {
nsIntSize size(DEFAULT_CANVAS_WIDTH, DEFAULT_CANVAS_HEIGHT);
const nsAttrValue* value;
if ((value = GetParsedAttr(nsGkAtoms::width)) &&
value->Type() == nsAttrValue::eInteger) {
size.width = value->GetIntegerValue();
}
if ((value = GetParsedAttr(nsGkAtoms::height)) &&
value->Type() == nsAttrValue::eInteger) {
size.height = value->GetIntegerValue();
}
MOZ_ASSERT(size.width >= 0 && size.height >= 0,
"we should've required <canvas> width/height attrs to be "
"unsigned (non-negative) values");
return size;
}
void HTMLCanvasElement::AfterSetAttr(int32_t aNamespaceID, nsAtom* aName,
const nsAttrValue* aValue,
const nsAttrValue* aOldValue,
nsIPrincipal* aSubjectPrincipal,
bool aNotify) {
AfterMaybeChangeAttr(aNamespaceID, aName, aNotify);
return nsGenericHTMLElement::AfterSetAttr(
aNamespaceID, aName, aValue, aOldValue, aSubjectPrincipal, aNotify);
}
void HTMLCanvasElement::OnAttrSetButNotChanged(
int32_t aNamespaceID, nsAtom* aName, const nsAttrValueOrString& aValue,
bool aNotify) {
AfterMaybeChangeAttr(aNamespaceID, aName, aNotify);
return nsGenericHTMLElement::OnAttrSetButNotChanged(aNamespaceID, aName,
aValue, aNotify);
}
void HTMLCanvasElement::AfterMaybeChangeAttr(int32_t aNamespaceID,
nsAtom* aName, bool aNotify) {
if (mCurrentContext && aNamespaceID == kNameSpaceID_None &&
(aName == nsGkAtoms::width || aName == nsGkAtoms::height ||
aName == nsGkAtoms::moz_opaque)) {
ErrorResult dummy;
UpdateContext(nullptr, JS::NullHandleValue, dummy);
}
}
void HTMLCanvasElement::HandlePrintCallback(nsPresContext* aPresContext) {
// Only call the print callback here if 1) we're in a print testing mode or
// print preview mode, 2) the canvas has a print callback and 3) the callback
// hasn't already been called. For real printing the callback is handled in
// nsPageSequenceFrame::PrePrintNextSheet.
if ((aPresContext->Type() == nsPresContext::eContext_PageLayout ||
aPresContext->Type() == nsPresContext::eContext_PrintPreview) &&
!mPrintState && GetMozPrintCallback()) {
DispatchPrintCallback(nullptr);
}
}
nsresult HTMLCanvasElement::DispatchPrintCallback(nsITimerCallback* aCallback) {
// For print reftests the context may not be initialized yet, so get a context
// so mCurrentContext is set.
if (!mCurrentContext) {
nsresult rv;
nsCOMPtr<nsISupports> context;
rv = GetContext(u"2d"_ns, getter_AddRefs(context));
NS_ENSURE_SUCCESS(rv, rv);
}
mPrintState = new HTMLCanvasPrintState(this, mCurrentContext, aCallback);
RefPtr<nsRunnableMethod<HTMLCanvasElement>> renderEvent =
NewRunnableMethod("dom::HTMLCanvasElement::CallPrintCallback", this,
&HTMLCanvasElement::CallPrintCallback);
return OwnerDoc()->Dispatch(TaskCategory::Other, renderEvent.forget());
}
void HTMLCanvasElement::CallPrintCallback() {
if (!mPrintState) {
// `mPrintState` might have been destroyed by cancelling the previous
// printing (especially the canvas frame destruction) during processing
// event loops in the printing.
return;
}
RefPtr<PrintCallback> callback = GetMozPrintCallback();
RefPtr<HTMLCanvasPrintState> state = mPrintState;
callback->Call(*state);
}
void HTMLCanvasElement::ResetPrintCallback() {
if (mPrintState) {
mPrintState = nullptr;
}
}
bool HTMLCanvasElement::IsPrintCallbackDone() {
if (mPrintState == nullptr) {
return true;
}
return mPrintState->mIsDone;
}
HTMLCanvasElement* HTMLCanvasElement::GetOriginalCanvas() {
return mOriginalCanvas ? mOriginalCanvas.get() : this;
}
nsresult HTMLCanvasElement::CopyInnerTo(HTMLCanvasElement* aDest) {
nsresult rv = nsGenericHTMLElement::CopyInnerTo(aDest);
NS_ENSURE_SUCCESS(rv, rv);
Document* destDoc = aDest->OwnerDoc();
if (destDoc->IsStaticDocument()) {
// The Firefox print preview code can create a static clone from an
// existing static clone, so we may not be the original 'canvas' element.
aDest->mOriginalCanvas = GetOriginalCanvas();
if (GetMozPrintCallback()) {
destDoc->SetHasPrintCallbacks();
}
// We make sure that the canvas is not zero sized since that would cause
// the DrawImage call below to return an error, which would cause printing
// to fail.
nsIntSize size = GetWidthHeight();
if (size.height > 0 && size.width > 0) {
nsCOMPtr<nsISupports> cxt;
aDest->GetContext(u"2d"_ns, getter_AddRefs(cxt));
RefPtr<CanvasRenderingContext2D> context2d =
static_cast<CanvasRenderingContext2D*>(cxt.get());
if (context2d && !mPrintCallback) {
CanvasImageSource source;
source.SetAsHTMLCanvasElement() = this;
ErrorResult err;
context2d->DrawImage(source, 0.0, 0.0, err);
rv = err.StealNSResult();
}
}
}
return rv;
}
nsChangeHint HTMLCanvasElement::GetAttributeChangeHint(const nsAtom* aAttribute,
int32_t aModType) const {
nsChangeHint retval =
nsGenericHTMLElement::GetAttributeChangeHint(aAttribute, aModType);
if (aAttribute == nsGkAtoms::width || aAttribute == nsGkAtoms::height) {
retval |= NS_STYLE_HINT_REFLOW;
} else if (aAttribute == nsGkAtoms::moz_opaque) {
retval |= NS_STYLE_HINT_VISUAL;
}
return retval;
}
void HTMLCanvasElement::MapAttributesIntoRule(
const nsMappedAttributes* aAttributes, MappedDeclarations& aDecls) {
MapAspectRatioInto(aAttributes, aDecls);
MapCommonAttributesInto(aAttributes, aDecls);
}
nsMapRuleToAttributesFunc HTMLCanvasElement::GetAttributeMappingFunction()
const {
return &MapAttributesIntoRule;
}
NS_IMETHODIMP_(bool)
HTMLCanvasElement::IsAttributeMapped(const nsAtom* aAttribute) const {
static const MappedAttributeEntry attributes[] = {
{nsGkAtoms::width}, {nsGkAtoms::height}, {nullptr}};
static const MappedAttributeEntry* const map[] = {attributes,
sCommonAttributeMap};
return FindAttributeDependence(aAttribute, map);
}
bool HTMLCanvasElement::ParseAttribute(int32_t aNamespaceID, nsAtom* aAttribute,
const nsAString& aValue,
nsIPrincipal* aMaybeScriptedPrincipal,
nsAttrValue& aResult) {
if (aNamespaceID == kNameSpaceID_None &&
(aAttribute == nsGkAtoms::width || aAttribute == nsGkAtoms::height)) {
return aResult.ParseNonNegativeIntValue(aValue);
}
return nsGenericHTMLElement::ParseAttribute(aNamespaceID, aAttribute, aValue,
aMaybeScriptedPrincipal, aResult);
}
void HTMLCanvasElement::ToDataURL(JSContext* aCx, const nsAString& aType,
JS::Handle<JS::Value> aParams,
nsAString& aDataURL,
nsIPrincipal& aSubjectPrincipal,
ErrorResult& aRv) {
// mWriteOnly check is redundant, but optimizes for the common case.
if (mWriteOnly && !CallerCanRead(&aSubjectPrincipal)) {
aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
return;
}
nsresult rv = ToDataURLImpl(aCx, aSubjectPrincipal, aType, aParams, aDataURL);
if (NS_FAILED(rv)) {
aDataURL.AssignLiteral("data:,");
}
}
void HTMLCanvasElement::SetMozPrintCallback(PrintCallback* aCallback) {
mPrintCallback = aCallback;
}
PrintCallback* HTMLCanvasElement::GetMozPrintCallback() const {
if (mOriginalCanvas) {
return mOriginalCanvas->GetMozPrintCallback();
}
return mPrintCallback;
}
static uint32_t sCaptureSourceId = 0;
class CanvasCaptureTrackSource : public MediaStreamTrackSource {
public:
NS_DECL_ISUPPORTS_INHERITED
NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(CanvasCaptureTrackSource,
MediaStreamTrackSource)
CanvasCaptureTrackSource(nsIPrincipal* aPrincipal,
CanvasCaptureMediaStream* aCaptureStream)
: MediaStreamTrackSource(
aPrincipal, nsString(),
TrackingId(TrackingId::Source::Canvas, sCaptureSourceId++,
TrackingId::TrackAcrossProcesses::Yes)),
mCaptureStream(aCaptureStream) {}
MediaSourceEnum GetMediaSource() const override {
return MediaSourceEnum::Other;
}
bool HasAlpha() const override {
if (!mCaptureStream || !mCaptureStream->Canvas()) {
// In cycle-collection
return false;
}
return !mCaptureStream->Canvas()->GetIsOpaque();
}
void Stop() override {
if (!mCaptureStream) {
NS_ERROR("No stream");
return;
}
mCaptureStream->StopCapture();
}
void Disable() override {}
void Enable() override {}
private:
virtual ~CanvasCaptureTrackSource() = default;
RefPtr<CanvasCaptureMediaStream> mCaptureStream;
};
NS_IMPL_ADDREF_INHERITED(CanvasCaptureTrackSource, MediaStreamTrackSource)
NS_IMPL_RELEASE_INHERITED(CanvasCaptureTrackSource, MediaStreamTrackSource)
NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(CanvasCaptureTrackSource)
NS_INTERFACE_MAP_END_INHERITING(MediaStreamTrackSource)
NS_IMPL_CYCLE_COLLECTION_INHERITED(CanvasCaptureTrackSource,
MediaStreamTrackSource, mCaptureStream)
already_AddRefed<CanvasCaptureMediaStream> HTMLCanvasElement::CaptureStream(
const Optional<double>& aFrameRate, nsIPrincipal& aSubjectPrincipal,
ErrorResult& aRv) {
if (IsWriteOnly()) {
aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
return nullptr;
}
nsPIDOMWindowInner* window = OwnerDoc()->GetInnerWindow();
if (!window) {
aRv.Throw(NS_ERROR_FAILURE);
return nullptr;
}
auto stream = MakeRefPtr<CanvasCaptureMediaStream>(window, this);
nsCOMPtr<nsIPrincipal> principal = NodePrincipal();
nsresult rv = stream->Init(aFrameRate, principal);
if (NS_FAILED(rv)) {
aRv.Throw(rv);
return nullptr;
}
RefPtr<MediaStreamTrack> track =
new VideoStreamTrack(window, stream->GetSourceStream(),
new CanvasCaptureTrackSource(principal, stream));
stream->AddTrackInternal(track);
// Check site-specific permission and display prompt if appropriate.
// If no permission, arrange for the frame capture listener to return
// all-white, opaque image data.
bool usePlaceholder = !CanvasUtils::IsImageExtractionAllowed(
OwnerDoc(), nsContentUtils::GetCurrentJSContext(),
Some(&aSubjectPrincipal));
rv = RegisterFrameCaptureListener(stream->FrameCaptureListener(),
usePlaceholder);
if (NS_FAILED(rv)) {
aRv.Throw(rv);
return nullptr;
}
return stream.forget();
}
nsresult HTMLCanvasElement::ExtractData(JSContext* aCx,
nsIPrincipal& aSubjectPrincipal,
nsAString& aType,
const nsAString& aOptions,
nsIInputStream** aStream) {
// Check site-specific permission and display prompt if appropriate.
// If no permission, return all-white, opaque image data.
bool usePlaceholder = !CanvasUtils::IsImageExtractionAllowed(
OwnerDoc(), aCx, Some(&aSubjectPrincipal));
return ImageEncoder::ExtractData(aType, aOptions, GetSize(), usePlaceholder,
mCurrentContext, mCanvasRenderer, aStream);
}
nsresult HTMLCanvasElement::ToDataURLImpl(JSContext* aCx,
nsIPrincipal& aSubjectPrincipal,
const nsAString& aMimeType,
const JS::Value& aEncoderOptions,
nsAString& aDataURL) {
nsIntSize size = GetWidthHeight();
if (size.height == 0 || size.width == 0) {
aDataURL = u"data:,"_ns;
return NS_OK;
}
nsAutoString type;
nsContentUtils::ASCIIToLower(aMimeType, type);
nsAutoString params;
bool usingCustomParseOptions;
nsresult rv =
ParseParams(aCx, type, aEncoderOptions, params, &usingCustomParseOptions);
if (NS_FAILED(rv)) {
return rv;
}
nsCOMPtr<nsIInputStream> stream;
rv =
ExtractData(aCx, aSubjectPrincipal, type, params, getter_AddRefs(stream));
// If there are unrecognized custom parse options, we should fall back to
// the default values for the encoder without any options at all.
if (rv == NS_ERROR_INVALID_ARG && usingCustomParseOptions) {
rv = ExtractData(aCx, aSubjectPrincipal, type, u""_ns,
getter_AddRefs(stream));
}
NS_ENSURE_SUCCESS(rv, rv);
// build data URL string
aDataURL = u"data:"_ns + type + u";base64,"_ns;
uint64_t count;
rv = stream->Available(&count);
NS_ENSURE_SUCCESS(rv, rv);
NS_ENSURE_TRUE(count <= UINT32_MAX, NS_ERROR_FILE_TOO_BIG);
return Base64EncodeInputStream(stream, aDataURL, (uint32_t)count,
aDataURL.Length());
}
void HTMLCanvasElement::ToBlob(JSContext* aCx, BlobCallback& aCallback,
const nsAString& aType,
JS::Handle<JS::Value> aParams,
nsIPrincipal& aSubjectPrincipal,
ErrorResult& aRv) {
// mWriteOnly check is redundant, but optimizes for the common case.
if (mWriteOnly && !CallerCanRead(&aSubjectPrincipal)) {
aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
return;
}
nsCOMPtr<nsIGlobalObject> global = OwnerDoc()->GetScopeObject();
MOZ_ASSERT(global);
nsIntSize elemSize = GetWidthHeight();
if (elemSize.width == 0 || elemSize.height == 0) {
// According to spec, blob should return null if either its horizontal
// dimension or its vertical dimension is zero. See link below.
// https://html.spec.whatwg.org/multipage/scripting.html#dom-canvas-toblob
OwnerDoc()->Dispatch(
TaskCategory::Other,
NewRunnableMethod<Blob*, const char*>(
"dom::HTMLCanvasElement::ToBlob", &aCallback,
static_cast<void (BlobCallback::*)(Blob*, const char*)>(
&BlobCallback::Call),
nullptr, nullptr));
return;
}
// Check site-specific permission and display prompt if appropriate.
// If no permission, return all-white, opaque image data.
bool usePlaceholder = !CanvasUtils::IsImageExtractionAllowed(
OwnerDoc(), aCx, Some(&aSubjectPrincipal));
CanvasRenderingContextHelper::ToBlob(aCx, global, aCallback, aType, aParams,
usePlaceholder, aRv);
}
OffscreenCanvas* HTMLCanvasElement::TransferControlToOffscreen(
ErrorResult& aRv) {
if (mCurrentContext || mOffscreenCanvas) {
aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
return nullptr;
}
MOZ_ASSERT(!mOffscreenDisplay);
nsPIDOMWindowInner* win = OwnerDoc()->GetInnerWindow();
if (!win) {
aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
return nullptr;
}
LayersBackend backend = LayersBackend::LAYERS_NONE;
TextureType textureType = TextureType::Unknown;
nsIWidget* docWidget = nsContentUtils::WidgetForDocument(OwnerDoc());
if (docWidget) {
WindowRenderer* renderer = docWidget->GetWindowRenderer();
if (renderer) {
backend = renderer->GetCompositorBackendType();
textureType = TexTypeForWebgl(renderer->AsKnowsCompositor());
}
}
nsIntSize sz = GetWidthHeight();
mOffscreenDisplay =
MakeRefPtr<OffscreenCanvasDisplayHelper>(this, sz.width, sz.height);
mOffscreenCanvas =
new OffscreenCanvas(win->AsGlobal(), sz.width, sz.height, backend,
textureType, do_AddRef(mOffscreenDisplay));
if (mWriteOnly) {
mOffscreenCanvas->SetWriteOnly(mExpandedReader);
}
if (!mContextObserver) {
mContextObserver = new HTMLCanvasElementObserver(this);
}
return mOffscreenCanvas;
}
nsresult HTMLCanvasElement::GetContext(const nsAString& aContextId,
nsISupports** aContext) {
ErrorResult rv;
mMaybeModified = true; // For FirstContentfulPaint
*aContext = GetContext(nullptr, aContextId, JS::NullHandleValue, rv).take();
return rv.StealNSResult();
}
already_AddRefed<nsISupports> HTMLCanvasElement::GetContext(
JSContext* aCx, const nsAString& aContextId,
JS::Handle<JS::Value> aContextOptions, ErrorResult& aRv) {
if (mOffscreenCanvas) {
aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
return nullptr;
}
mMaybeModified = true; // For FirstContentfulPaint
return CanvasRenderingContextHelper::GetOrCreateContext(
aCx, aContextId,
aContextOptions.isObject() ? aContextOptions : JS::NullHandleValue, aRv);
}
nsIntSize HTMLCanvasElement::GetSize() { return GetWidthHeight(); }
bool HTMLCanvasElement::IsWriteOnly() const { return mWriteOnly; }
void HTMLCanvasElement::SetWriteOnly(
nsIPrincipal* aExpandedReader /* = nullptr */) {
mExpandedReader = aExpandedReader;
mWriteOnly = true;
if (mOffscreenCanvas) {
mOffscreenCanvas->SetWriteOnly(aExpandedReader);
}
}
bool HTMLCanvasElement::CallerCanRead(nsIPrincipal* aPrincipal) const {
if (!mWriteOnly) {
return true;
}
if (!aPrincipal) {
return false;
}
// If mExpandedReader is set, this canvas was tainted only by
// mExpandedReader's resources. So allow reading if the subject
// principal subsumes mExpandedReader.
if (mExpandedReader && aPrincipal->Subsumes(mExpandedReader)) {
return true;
}
return nsContentUtils::PrincipalHasPermission(*aPrincipal,
nsGkAtoms::all_urlsPermission);
}
void HTMLCanvasElement::SetWidth(uint32_t aWidth, ErrorResult& aRv) {
if (mOffscreenCanvas) {
aRv.ThrowInvalidStateError(
"Cannot set width of placeholder canvas transferred to "
"OffscreenCanvas.");
return;
}
SetUnsignedIntAttr(nsGkAtoms::width, aWidth, DEFAULT_CANVAS_WIDTH, aRv);
}
void HTMLCanvasElement::SetHeight(uint32_t aHeight, ErrorResult& aRv) {
if (mOffscreenCanvas) {
aRv.ThrowInvalidStateError(
"Cannot set height of placeholder canvas transferred to "
"OffscreenCanvas.");
return;
}
SetUnsignedIntAttr(nsGkAtoms::height, aHeight, DEFAULT_CANVAS_HEIGHT, aRv);
}
void HTMLCanvasElement::FlushOffscreenCanvas() {
if (mOffscreenDisplay) {
mOffscreenDisplay->FlushForDisplay();
}
}
void HTMLCanvasElement::InvalidateCanvasPlaceholder(uint32_t aWidth,
uint32_t aHeight) {
ErrorResult rv;
SetUnsignedIntAttr(nsGkAtoms::width, aWidth, DEFAULT_CANVAS_WIDTH, rv);
MOZ_ASSERT(!rv.Failed());
SetUnsignedIntAttr(nsGkAtoms::height, aHeight, DEFAULT_CANVAS_HEIGHT, rv);
MOZ_ASSERT(!rv.Failed());
}
void HTMLCanvasElement::InvalidateCanvasContent(const gfx::Rect* damageRect) {
// Cache the current ImageContainer to avoid contention on the mutex.
if (mOffscreenDisplay) {
mImageContainer = mOffscreenDisplay->GetImageContainer();
}
// We don't need to flush anything here; if there's no frame or if
// we plan to reframe we don't need to invalidate it anyway.
nsIFrame* frame = GetPrimaryFrame();
if (!frame) return;
// When using layers-free WebRender, we cannot invalidate the layer (because
// there isn't one). Instead, we mark the CanvasRenderer dirty and scheduling
// an empty transaction which is effectively equivalent.
CanvasRenderer* renderer = nullptr;
const auto key = static_cast<uint32_t>(DisplayItemType::TYPE_CANVAS);
RefPtr<WebRenderCanvasData> data =
GetWebRenderUserData<WebRenderCanvasData>(frame, key);
if (data) {
renderer = data->GetCanvasRenderer();
}
if (renderer) {
renderer->SetDirty();
frame->SchedulePaint(nsIFrame::PAINT_COMPOSITE_ONLY);
} else {
if (damageRect) {
nsIntSize size = GetWidthHeight();
if (size.width != 0 && size.height != 0) {
gfx::IntRect invalRect = gfx::IntRect::Truncate(*damageRect);
frame->InvalidateLayer(DisplayItemType::TYPE_CANVAS, &invalRect);
}
} else {
frame->InvalidateLayer(DisplayItemType::TYPE_CANVAS);
}
// This path is taken in two situations:
// 1) WebRender is enabled and has not yet processed a display list.
// 2) WebRender is disabled and layer invalidation failed.
// In both cases, schedule a full paint to properly update canvas.
frame->SchedulePaint(nsIFrame::PAINT_DEFAULT, false);
}
/*
* Treat canvas invalidations as animation activity for JS. Frequently
* invalidating a canvas will feed into heuristics and cause JIT code to be
* kept around longer, for smoother animations.
*/
nsPIDOMWindowInner* win = OwnerDoc()->GetInnerWindow();
if (win) {
if (JSObject* obj = win->AsGlobal()->GetGlobalJSObject()) {
js::NotifyAnimationActivity(obj);
}
}
}
void HTMLCanvasElement::InvalidateCanvas() {
// We don't need to flush anything here; if there's no frame or if
// we plan to reframe we don't need to invalidate it anyway.
nsIFrame* frame = GetPrimaryFrame();
if (!frame) return;
frame->InvalidateFrame();
}
bool HTMLCanvasElement::GetIsOpaque() {
if (mCurrentContext) {
return mCurrentContext->GetIsOpaque();
}
return GetOpaqueAttr();
}
bool HTMLCanvasElement::GetOpaqueAttr() {
return HasAttr(kNameSpaceID_None, nsGkAtoms::moz_opaque);
}
CanvasContextType HTMLCanvasElement::GetCurrentContextType() {
if (mCurrentContextType == CanvasContextType::NoContext &&
mOffscreenDisplay) {
mCurrentContextType = mOffscreenDisplay->GetContextType();
}
return mCurrentContextType;
}
already_AddRefed<Image> HTMLCanvasElement::GetAsImage() {
if (mOffscreenDisplay) {
return mOffscreenDisplay->GetAsImage();
}
if (mCurrentContext) {
return mCurrentContext->GetAsImage();
}
return nullptr;
}
bool HTMLCanvasElement::UpdateWebRenderCanvasData(
nsDisplayListBuilder* aBuilder, WebRenderCanvasData* aCanvasData) {
MOZ_ASSERT(!mOffscreenDisplay);
if (mCurrentContext) {
return mCurrentContext->UpdateWebRenderCanvasData(aBuilder, aCanvasData);
}
// Clear CanvasRenderer of WebRenderCanvasData
aCanvasData->ClearCanvasRenderer();
return false;
}
bool HTMLCanvasElement::InitializeCanvasRenderer(nsDisplayListBuilder* aBuilder,
CanvasRenderer* aRenderer) {
MOZ_ASSERT(!mOffscreenDisplay);
if (mCurrentContext) {
return mCurrentContext->InitializeCanvasRenderer(aBuilder, aRenderer);
}
return false;
}
void HTMLCanvasElement::MarkContextClean() {
if (!mCurrentContext) return;
mCurrentContext->MarkContextClean();
}
void HTMLCanvasElement::MarkContextCleanForFrameCapture() {
if (!mCurrentContext) return;
mCurrentContext->MarkContextCleanForFrameCapture();
}
Watchable<FrameCaptureState>* HTMLCanvasElement::GetFrameCaptureState() {
if (!mCurrentContext) {
return nullptr;
}
return mCurrentContext->GetFrameCaptureState();
}
nsresult HTMLCanvasElement::RegisterFrameCaptureListener(
FrameCaptureListener* aListener, bool aReturnPlaceholderData) {
WeakPtr<FrameCaptureListener> listener = aListener;
if (mRequestedFrameListeners.Contains(listener)) {
return NS_OK;
}
if (!mRequestedFrameRefreshObserver) {
Document* doc = OwnerDoc();
if (!doc) {
return NS_ERROR_FAILURE;
}
PresShell* shell = nsContentUtils::FindPresShellForDocument(doc);
if (!shell) {
return NS_ERROR_FAILURE;
}
nsPresContext* context = shell->GetPresContext();
if (!context) {
return NS_ERROR_FAILURE;
}
context = context->GetRootPresContext();
if (!context) {
return NS_ERROR_FAILURE;
}
nsRefreshDriver* driver = context->RefreshDriver();
if (!driver) {
return NS_ERROR_FAILURE;
}
mRequestedFrameRefreshObserver =
new RequestedFrameRefreshObserver(this, driver, aReturnPlaceholderData);
} else {
mRequestedFrameRefreshObserver->SetReturnPlaceholderData(
aReturnPlaceholderData);
}
mRequestedFrameListeners.AppendElement(listener);
mRequestedFrameRefreshObserver->Register();
return NS_OK;
}
bool HTMLCanvasElement::IsFrameCaptureRequested(const TimeStamp& aTime) const {
for (WeakPtr<FrameCaptureListener> listener : mRequestedFrameListeners) {
if (!listener) {
continue;
}
if (listener->FrameCaptureRequested(aTime)) {
return true;
}
}
return false;
}
void HTMLCanvasElement::ProcessDestroyedFrameListeners() {
// Remove destroyed listeners from the list.
mRequestedFrameListeners.RemoveElementsBy(
[](const auto& weakListener) { return !weakListener; });
if (mRequestedFrameListeners.IsEmpty()) {
mRequestedFrameRefreshObserver->Unregister();
}
}
void HTMLCanvasElement::SetFrameCapture(
already_AddRefed<SourceSurface> aSurface, const TimeStamp& aTime) {
RefPtr<SourceSurface> surface = aSurface;
RefPtr<SourceSurfaceImage> image =
new SourceSurfaceImage(surface->GetSize(), surface);
for (WeakPtr<FrameCaptureListener> listener : mRequestedFrameListeners) {
if (!listener) {
continue;
}
RefPtr<Image> imageRefCopy = image.get();
listener->NewFrame(imageRefCopy.forget(), aTime);
}
}
already_AddRefed<SourceSurface> HTMLCanvasElement::GetSurfaceSnapshot(
gfxAlphaType* const aOutAlphaType, DrawTarget* aTarget) {
if (mCurrentContext) {
return mCurrentContext->GetOptimizedSnapshot(aTarget, aOutAlphaType);
} else if (mOffscreenDisplay) {
return mOffscreenDisplay->GetSurfaceSnapshot();
}
return nullptr;
}
layers::LayersBackend HTMLCanvasElement::GetCompositorBackendType() const {
nsIWidget* docWidget = nsContentUtils::WidgetForDocument(OwnerDoc());
if (docWidget) {
WindowRenderer* renderer = docWidget->GetWindowRenderer();
if (renderer) {
return renderer->GetCompositorBackendType();
}
}
return LayersBackend::LAYERS_NONE;
}
void HTMLCanvasElement::OnMemoryPressure() {
// FIXME(aosmond): We need to implement memory pressure handling for
// OffscreenCanvas when it is on worker threads. See bug 1746260.
if (mCurrentContext) {
mCurrentContext->OnMemoryPressure();
}
}
void HTMLCanvasElement::OnDeviceReset() {
if (!mOffscreenCanvas && mCurrentContext) {
mCurrentContext->ResetBitmap();
}
}
ClientWebGLContext* HTMLCanvasElement::GetWebGLContext() {
if (GetCurrentContextType() != CanvasContextType::WebGL1 &&
GetCurrentContextType() != CanvasContextType::WebGL2) {
return nullptr;
}
return static_cast<ClientWebGLContext*>(GetCurrentContext());
}
webgpu::CanvasContext* HTMLCanvasElement::GetWebGPUContext() {
if (GetCurrentContextType() != CanvasContextType::WebGPU) {
return nullptr;
}
return static_cast<webgpu::CanvasContext*>(GetCurrentContext());
}
} // namespace mozilla::dom
