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gecko-dev/dom/html/HTMLCanvasElement.cpp

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/* -*- 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 "Layers.h"
#include "MediaStreamGraph.h"
#include "mozilla/Assertions.h"
#include "mozilla/Base64.h"
#include "mozilla/CheckedInt.h"
#include "mozilla/dom/CanvasCaptureMediaStream.h"
#include "mozilla/dom/CanvasRenderingContext2D.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/EventDispatcher.h"
#include "mozilla/gfx/Rect.h"
#include "mozilla/layers/AsyncCanvasRenderer.h"
#include "mozilla/layers/WebRenderCanvasRenderer.h"
#include "mozilla/layers/WebRenderUserData.h"
#include "mozilla/MouseEvents.h"
#include "mozilla/Preferences.h"
#include "mozilla/Telemetry.h"
#include "nsAttrValueInlines.h"
#include "nsContentUtils.h"
#include "nsDisplayList.h"
#include "nsDOMJSUtils.h"
#include "nsIScriptSecurityManager.h"
#include "nsITimer.h"
#include "nsIWritablePropertyBag2.h"
#include "nsIXPConnect.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 "WebGL1Context.h"
#include "WebGL2Context.h"
using namespace mozilla::layers;
using namespace mozilla::gfx;
NS_IMPL_NS_NEW_HTML_ELEMENT(Canvas)
namespace mozilla {
namespace 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) {
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) {
// If returning placeholder data, fill the frame copy with white pixels.
memset(write.GetData(), 0xFF, write.GetStride() * copy->GetSize().height);
} else {
memcpy(write.GetData(), read.GetData(),
write.GetStride() * copy->GetSize().height);
}
return copy.forget();
}
void SetReturnPlaceholderData(bool aReturnPlaceholderData) {
mReturnPlaceholderData = aReturnPlaceholderData;
}
void WillRefresh(TimeStamp aTime) override {
MOZ_ASSERT(NS_IsMainThread());
AUTO_PROFILER_LABEL("RequestedFrameRefreshObserver::WillRefresh", OTHER);
if (!mOwningElement) {
return;
}
if (mOwningElement->IsWriteOnly()) {
return;
}
if (mOwningElement->IsContextCleanForFrameCapture()) {
return;
}
mOwningElement->ProcessDestroyedFrameListeners();
if (!mOwningElement->IsFrameCaptureRequested()) {
return;
}
RefPtr<SourceSurface> snapshot;
{
AUTO_PROFILER_LABEL(
"RequestedFrameRefreshObserver::WillRefresh:GetSnapshot", OTHER);
snapshot = mOwningElement->GetSurfaceSnapshot(nullptr);
if (!snapshot) {
return;
}
}
RefPtr<DataSourceSurface> copy;
{
AUTO_PROFILER_LABEL(
"RequestedFrameRefreshObserver::WillRefresh:CopySurface", OTHER);
copy = CopySurface(snapshot, mReturnPlaceholderData);
if (!copy) {
return;
}
}
{
AUTO_PROFILER_LABEL("RequestedFrameRefreshObserver::WillRefresh:SetFrame",
OTHER);
mOwningElement->SetFrameCapture(copy.forget(), aTime);
mOwningElement->MarkContextCleanForFrameCapture();
}
}
void DetachFromRefreshDriver() {
MOZ_ASSERT(mOwningElement);
MOZ_ASSERT(mRefreshDriver);
Unregister();
mRefreshDriver = nullptr;
}
void Register() {
if (mRegistered) {
return;
}
MOZ_ASSERT(mRefreshDriver);
if (mRefreshDriver) {
mRefreshDriver->AddRefreshObserver(this, FlushType::Display);
mRegistered = true;
}
}
void Unregister() {
if (!mRegistered) {
return;
}
MOZ_ASSERT(mRefreshDriver);
if (mRefreshDriver) {
mRefreshDriver->RemoveRefreshObserver(this, FlushType::Display);
mRegistered = false;
}
}
private:
virtual ~RequestedFrameRefreshObserver() {
MOZ_ASSERT(!mRefreshDriver);
MOZ_ASSERT(!mRegistered);
}
bool mRegistered;
bool mReturnPlaceholderData;
HTMLCanvasElement* const mOwningElement;
RefPtr<nsRefreshDriver> mRefreshDriver;
};
// ---------------------------------------------------------------------------
NS_IMPL_CYCLE_COLLECTION_WRAPPERCACHE(HTMLCanvasPrintState, mCanvas, mContext,
mCallback)
NS_IMPL_CYCLE_COLLECTION_ROOT_NATIVE(HTMLCanvasPrintState, AddRef)
NS_IMPL_CYCLE_COLLECTION_UNROOT_NATIVE(HTMLCanvasPrintState, Release)
HTMLCanvasPrintState::HTMLCanvasPrintState(
HTMLCanvasElement* aCanvas, nsICanvasRenderingContextInternal* aContext,
nsITimerCallback* aCallback)
: mIsDone(false),
mPendingNotify(false),
mCanvas(aCanvas),
mContext(aContext),
mCallback(aCallback) {}
HTMLCanvasPrintState::~HTMLCanvasPrintState() {}
/* 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) {
RegisterVisibilityChangeEvent();
RegisterMemoryPressureEvent();
}
HTMLCanvasElementObserver::~HTMLCanvasElementObserver() { Destroy(); }
void HTMLCanvasElementObserver::Destroy() {
UnregisterMemoryPressureEvent();
UnregisterVisibilityChangeEvent();
mElement = nullptr;
}
void HTMLCanvasElementObserver::RegisterVisibilityChangeEvent() {
if (!mElement) {
return;
}
Document* document = mElement->OwnerDoc();
document->AddSystemEventListener(NS_LITERAL_STRING("visibilitychange"), this,
true, false);
}
void HTMLCanvasElementObserver::UnregisterVisibilityChangeEvent() {
if (!mElement) {
return;
}
Document* document = mElement->OwnerDoc();
document->RemoveSystemEventListener(NS_LITERAL_STRING("visibilitychange"),
this, true);
}
void HTMLCanvasElementObserver::RegisterMemoryPressureEvent() {
if (!mElement) {
return;
}
nsCOMPtr<nsIObserverService> observerService =
mozilla::services::GetObserverService();
MOZ_ASSERT(observerService);
if (observerService)
observerService->AddObserver(this, "memory-pressure", false);
}
void HTMLCanvasElementObserver::UnregisterMemoryPressureEvent() {
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");
}
NS_IMETHODIMP
HTMLCanvasElementObserver::Observe(nsISupports*, const char* aTopic,
const char16_t*) {
if (!mElement || strcmp(aTopic, "memory-pressure")) {
return NS_OK;
}
mElement->OnMemoryPressure();
return NS_OK;
}
NS_IMETHODIMP
HTMLCanvasElementObserver::HandleEvent(Event* aEvent) {
nsAutoString type;
aEvent->GetType(type);
if (!mElement || !type.EqualsLiteral("visibilitychange")) {
return NS_OK;
}
mElement->OnVisibilityChange();
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() {
if (mContextObserver) {
mContextObserver->Destroy();
mContextObserver = nullptr;
}
ResetPrintCallback();
if (mRequestedFrameRefreshObserver) {
mRequestedFrameRefreshObserver->DetachFromRefreshDriver();
}
if (mAsyncCanvasRenderer) {
mAsyncCanvasRenderer->mHTMLCanvasElement = nullptr;
}
}
NS_IMPL_CYCLE_COLLECTION_INHERITED(HTMLCanvasElement, nsGenericHTMLElement,
mCurrentContext, mPrintCallback, mPrintState,
mOriginalCanvas, mOffscreenCanvas)
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) {
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;
}
nsresult 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);
}
nsresult 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::nsPresContextType aType) {
// 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
// nsSimplePageSequenceFrame::PrePrintNextPage.
if ((aType == nsPresContext::eContext_PageLayout ||
aType == 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(NS_LITERAL_STRING("2d"), 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());
}
MOZ_CAN_RUN_SCRIPT
void HTMLCanvasElement::CallPrintCallback() {
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);
if (aDest->OwnerDoc()->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();
// 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(NS_LITERAL_STRING("2d"), 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;
}
void HTMLCanvasElement::GetEventTargetParent(EventChainPreVisitor& aVisitor) {
if (aVisitor.mEvent->mClass == eMouseEventClass) {
WidgetMouseEventBase* evt = (WidgetMouseEventBase*)aVisitor.mEvent;
if (mCurrentContext) {
nsIFrame* frame = GetPrimaryFrame();
if (!frame) {
return;
}
nsPoint ptInRoot =
nsLayoutUtils::GetEventCoordinatesRelativeTo(evt, frame);
nsRect paddingRect = frame->GetContentRectRelativeToSelf();
Point hitpoint;
hitpoint.x = (ptInRoot.x - paddingRect.x) / AppUnitsPerCSSPixel();
hitpoint.y = (ptInRoot.y - paddingRect.y) / AppUnitsPerCSSPixel();
evt->mRegion = mCurrentContext->GetHitRegion(hitpoint);
aVisitor.mCanHandle = true;
}
}
nsGenericHTMLElement::GetEventTargetParent(aVisitor);
}
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;
}
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(aCx)) {
aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
return;
}
aRv = ToDataURLImpl(aCx, aSubjectPrincipal, aType, aParams, aDataURL);
}
void HTMLCanvasElement::SetMozPrintCallback(PrintCallback* aCallback) {
mPrintCallback = aCallback;
}
PrintCallback* HTMLCanvasElement::GetMozPrintCallback() const {
if (mOriginalCanvas) {
return mOriginalCanvas->GetMozPrintCallback();
}
return mPrintCallback;
}
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()),
mCaptureStream(aCaptureStream) {}
MediaSourceEnum GetMediaSource() const override {
return MediaSourceEnum::Other;
}
void Stop() override {
if (!mCaptureStream) {
NS_ERROR("No stream");
return;
}
mCaptureStream->StopCapture();
}
void Disable() override {}
void Enable() override {}
private:
virtual ~CanvasCaptureTrackSource() {}
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;
}
if (!mCurrentContext) {
aRv.Throw(NS_ERROR_NOT_INITIALIZED);
return nullptr;
}
auto stream = MakeRefPtr<CanvasCaptureMediaStream>(window, this);
const TrackID videoTrackId = 1;
nsCOMPtr<nsIPrincipal> principal = NodePrincipal();
nsresult rv = stream->Init(aFrameRate, videoTrackId, principal);
if (NS_FAILED(rv)) {
aRv.Throw(rv);
return nullptr;
}
RefPtr<MediaStreamTrack> track =
new VideoStreamTrack(window, stream->GetSourceStream(), videoTrackId,
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(), 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, aSubjectPrincipal);
return ImageEncoder::ExtractData(aType, aOptions, GetSize(), usePlaceholder,
mCurrentContext, mAsyncCanvasRenderer,
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 = NS_LITERAL_STRING("data:,");
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, EmptyString(),
getter_AddRefs(stream));
}
NS_ENSURE_SUCCESS(rv, rv);
// build data URL string
aDataURL = NS_LITERAL_STRING("data:") + type + NS_LITERAL_STRING(";base64,");
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(aCx)) {
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, aSubjectPrincipal);
CanvasRenderingContextHelper::ToBlob(aCx, global, aCallback, aType, aParams,
usePlaceholder, aRv);
}
OffscreenCanvas* HTMLCanvasElement::TransferControlToOffscreen(
ErrorResult& aRv) {
if (mCurrentContext) {
aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
return nullptr;
}
if (!mOffscreenCanvas) {
nsIntSize sz = GetWidthHeight();
RefPtr<AsyncCanvasRenderer> renderer = GetAsyncCanvasRenderer();
renderer->SetWidth(sz.width);
renderer->SetHeight(sz.height);
nsPIDOMWindowInner* win = OwnerDoc()->GetInnerWindow();
if (!win) {
aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
return nullptr;
}
mOffscreenCanvas =
new OffscreenCanvas(win->AsGlobal(), sz.width, sz.height,
GetCompositorBackendType(), renderer);
if (mWriteOnly) {
mOffscreenCanvas->SetWriteOnly();
}
if (!mContextObserver) {
mContextObserver = new HTMLCanvasElementObserver(this);
}
} else {
aRv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
}
return mOffscreenCanvas;
}
already_AddRefed<File> HTMLCanvasElement::MozGetAsFile(
const nsAString& aName, const nsAString& aType,
nsIPrincipal& aSubjectPrincipal, ErrorResult& aRv) {
OwnerDoc()->WarnOnceAbout(Document::eMozGetAsFile);
// do a trust check if this is a write-only canvas
if (mWriteOnly && !nsContentUtils::IsSystemPrincipal(&aSubjectPrincipal)) {
aRv.Throw(NS_ERROR_DOM_SECURITY_ERR);
return nullptr;
}
RefPtr<File> file;
aRv = MozGetAsFileImpl(aName, aType, aSubjectPrincipal, getter_AddRefs(file));
if (NS_WARN_IF(aRv.Failed())) {
return nullptr;
}
return file.forget();
}
nsresult HTMLCanvasElement::MozGetAsFileImpl(const nsAString& aName,
const nsAString& aType,
nsIPrincipal& aSubjectPrincipal,
File** aResult) {
nsCOMPtr<nsIInputStream> stream;
nsAutoString type(aType);
nsresult rv =
ExtractData(nsContentUtils::GetCurrentJSContext(), aSubjectPrincipal,
type, EmptyString(), getter_AddRefs(stream));
NS_ENSURE_SUCCESS(rv, rv);
uint64_t imgSize;
void* imgData = nullptr;
rv = NS_ReadInputStreamToBuffer(stream, &imgData, -1, &imgSize);
NS_ENSURE_SUCCESS(rv, rv);
nsCOMPtr<nsPIDOMWindowInner> win =
do_QueryInterface(OwnerDoc()->GetScopeObject());
// The File takes ownership of the buffer
RefPtr<File> file =
File::CreateMemoryFile(win, imgData, imgSize, aName, type, PR_Now());
file.forget(aResult);
return NS_OK;
}
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) {
return nullptr;
}
mMaybeModified = true; // For FirstContentfulPaint
return CanvasRenderingContextHelper::GetContext(
aCx, aContextId,
aContextOptions.isObject() ? aContextOptions : JS::NullHandleValue, aRv);
}
already_AddRefed<nsISupports> HTMLCanvasElement::MozGetIPCContext(
const nsAString& aContextId, ErrorResult& aRv) {
// Note that we're a [ChromeOnly] method, so from JS we can only be called by
// system code.
// We only support 2d shmem contexts for now.
if (!aContextId.EqualsLiteral("2d")) {
aRv.Throw(NS_ERROR_INVALID_ARG);
return nullptr;
}
CanvasContextType contextType = CanvasContextType::Canvas2D;
if (!mCurrentContext) {
// This canvas doesn't have a context yet.
RefPtr<nsICanvasRenderingContextInternal> context;
context = CreateContext(contextType);
if (!context) {
return nullptr;
}
mCurrentContext = context;
mCurrentContext->SetIsIPC(true);
mCurrentContextType = contextType;
ErrorResult dummy;
nsresult rv = UpdateContext(nullptr, JS::NullHandleValue, dummy);
if (NS_WARN_IF(NS_FAILED(rv))) {
aRv.Throw(rv);
return nullptr;
}
} else {
// We already have a context of some type.
if (contextType != mCurrentContextType) {
aRv.Throw(NS_ERROR_INVALID_ARG);
return nullptr;
}
}
nsCOMPtr<nsISupports> context(mCurrentContext);
return context.forget();
}
nsIntSize HTMLCanvasElement::GetSize() { return GetWidthHeight(); }
bool HTMLCanvasElement::IsWriteOnly() const { return mWriteOnly; }
void HTMLCanvasElement::SetWriteOnly() {
mExpandedReader = nullptr;
mWriteOnly = true;
}
void HTMLCanvasElement::SetWriteOnly(nsIPrincipal* aExpandedReader) {
mExpandedReader = aExpandedReader;
mWriteOnly = true;
}
bool HTMLCanvasElement::CallerCanRead(JSContext* aCx) {
if (!mWriteOnly) {
return true;
}
nsIPrincipal* prin = nsContentUtils::SubjectPrincipal(aCx);
// If mExpandedReader is set, this canvas was tainted only by
// mExpandedReader's resources. So allow reading if the subject
// principal subsumes mExpandedReader.
if (mExpandedReader && prin->Subsumes(mExpandedReader)) {
return true;
}
return nsContentUtils::PrincipalHasPermission(prin,
nsGkAtoms::all_urlsPermission);
}
void HTMLCanvasElement::InvalidateCanvasContent(const gfx::Rect* damageRect) {
// 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;
ActiveLayerTracker::NotifyContentChange(frame);
// 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;
RefPtr<WebRenderCanvasData> data = GetWebRenderUserData<WebRenderCanvasData>(
frame, static_cast<uint32_t>(DisplayItemType::TYPE_CANVAS));
if (data) {
renderer = data->GetCanvasRenderer();
}
if (renderer) {
renderer->SetDirty();
frame->SchedulePaint(nsIFrame::PAINT_COMPOSITE_ONLY);
} else {
Layer* layer = nullptr;
if (damageRect) {
nsIntSize size = GetWidthHeight();
if (size.width != 0 && size.height != 0) {
gfx::IntRect invalRect = gfx::IntRect::Truncate(*damageRect);
layer =
frame->InvalidateLayer(DisplayItemType::TYPE_CANVAS, &invalRect);
}
} else {
layer = frame->InvalidateLayer(DisplayItemType::TYPE_CANVAS);
}
if (layer) {
static_cast<CanvasLayer*>(layer)->Updated();
}
}
/*
* 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();
}
int32_t HTMLCanvasElement::CountContexts() {
if (mCurrentContext) return 1;
return 0;
}
nsICanvasRenderingContextInternal* HTMLCanvasElement::GetContextAtIndex(
int32_t index) {
if (mCurrentContext && index == 0) return mCurrentContext;
return nullptr;
}
bool HTMLCanvasElement::GetIsOpaque() {
if (mCurrentContext) {
return mCurrentContext->GetIsOpaque();
}
return GetOpaqueAttr();
}
bool HTMLCanvasElement::GetOpaqueAttr() {
return HasAttr(kNameSpaceID_None, nsGkAtoms::moz_opaque);
}
already_AddRefed<Layer> HTMLCanvasElement::GetCanvasLayer(
nsDisplayListBuilder* aBuilder, Layer* aOldLayer, LayerManager* aManager) {
// The address of sOffscreenCanvasLayerUserDataDummy is used as the user
// data key for retained LayerManagers managed by FrameLayerBuilder.
// We don't much care about what value in it, so just assign a dummy
// value for it.
static uint8_t sOffscreenCanvasLayerUserDataDummy = 0;
if (mCurrentContext) {
return mCurrentContext->GetCanvasLayer(aBuilder, aOldLayer, aManager);
}
if (mOffscreenCanvas) {
if (!mResetLayer && aOldLayer &&
aOldLayer->HasUserData(&sOffscreenCanvasLayerUserDataDummy)) {
RefPtr<Layer> ret = aOldLayer;
return ret.forget();
}
RefPtr<CanvasLayer> layer = aManager->CreateCanvasLayer();
if (!layer) {
NS_WARNING("CreateCanvasLayer failed!");
return nullptr;
}
LayerUserData* userData = nullptr;
layer->SetUserData(&sOffscreenCanvasLayerUserDataDummy, userData);
CanvasRenderer* canvasRenderer = layer->CreateOrGetCanvasRenderer();
if (!InitializeCanvasRenderer(aBuilder, canvasRenderer)) {
return nullptr;
}
layer->Updated();
return layer.forget();
}
return nullptr;
}
bool HTMLCanvasElement::UpdateWebRenderCanvasData(
nsDisplayListBuilder* aBuilder, WebRenderCanvasData* aCanvasData) {
if (mCurrentContext) {
return mCurrentContext->UpdateWebRenderCanvasData(aBuilder, aCanvasData);
}
if (mOffscreenCanvas) {
CanvasRenderer* renderer = aCanvasData->GetCanvasRenderer();
if (!mResetLayer && renderer) {
return true;
}
renderer = aCanvasData->CreateCanvasRenderer();
if (!InitializeCanvasRenderer(aBuilder, renderer)) {
// Clear CanvasRenderer of WebRenderCanvasData
aCanvasData->ClearCanvasRenderer();
return false;
}
MOZ_ASSERT(renderer);
mResetLayer = false;
return true;
}
// Clear CanvasRenderer of WebRenderCanvasData
aCanvasData->ClearCanvasRenderer();
return false;
}
bool HTMLCanvasElement::InitializeCanvasRenderer(nsDisplayListBuilder* aBuilder,
CanvasRenderer* aRenderer) {
if (mCurrentContext) {
return mCurrentContext->InitializeCanvasRenderer(aBuilder, aRenderer);
}
if (mOffscreenCanvas) {
CanvasInitializeData data;
data.mRenderer = GetAsyncCanvasRenderer();
data.mSize = GetWidthHeight();
aRenderer->Initialize(data);
return true;
}
return false;
}
bool HTMLCanvasElement::ShouldForceInactiveLayer(LayerManager* aManager) {
if (mCurrentContext) {
return mCurrentContext->ShouldForceInactiveLayer(aManager);
}
if (mOffscreenCanvas) {
// TODO: We should handle offscreen canvas case.
return false;
}
return true;
}
void HTMLCanvasElement::MarkContextClean() {
if (!mCurrentContext) return;
mCurrentContext->MarkContextClean();
}
void HTMLCanvasElement::MarkContextCleanForFrameCapture() {
if (!mCurrentContext) return;
mCurrentContext->MarkContextCleanForFrameCapture();
}
bool HTMLCanvasElement::IsContextCleanForFrameCapture() {
return mCurrentContext && mCurrentContext->IsContextCleanForFrameCapture();
}
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;
}
while (doc->GetInProcessParentDocument()) {
doc = doc->GetInProcessParentDocument();
}
nsPresContext* context = doc->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 {
for (WeakPtr<FrameCaptureListener> listener : mRequestedFrameListeners) {
if (!listener) {
continue;
}
if (listener->FrameCaptureRequested()) {
return true;
}
}
return false;
}
void HTMLCanvasElement::ProcessDestroyedFrameListeners() {
// Loop backwards to allow removing elements in the loop.
for (int i = mRequestedFrameListeners.Length() - 1; i >= 0; --i) {
WeakPtr<FrameCaptureListener> listener = mRequestedFrameListeners[i];
if (!listener) {
// listener was destroyed. Remove it from the list.
mRequestedFrameListeners.RemoveElementAt(i);
continue;
}
}
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) {
if (!mCurrentContext) return nullptr;
return mCurrentContext->GetSurfaceSnapshot(aOutAlphaType);
}
AsyncCanvasRenderer* HTMLCanvasElement::GetAsyncCanvasRenderer() {
if (!mAsyncCanvasRenderer) {
mAsyncCanvasRenderer = new AsyncCanvasRenderer();
mAsyncCanvasRenderer->mHTMLCanvasElement = this;
}
return mAsyncCanvasRenderer;
}
layers::LayersBackend HTMLCanvasElement::GetCompositorBackendType() const {
nsIWidget* docWidget = nsContentUtils::WidgetForDocument(OwnerDoc());
if (docWidget) {
layers::LayerManager* layerManager = docWidget->GetLayerManager();
if (layerManager) {
return layerManager->GetCompositorBackendType();
}
}
return LayersBackend::LAYERS_NONE;
}
void HTMLCanvasElement::OnVisibilityChange() {
if (OwnerDoc()->Hidden()) {
return;
}
if (mOffscreenCanvas) {
class Runnable final : public CancelableRunnable {
public:
explicit Runnable(AsyncCanvasRenderer* aRenderer)
: mozilla::CancelableRunnable("Runnable"), mRenderer(aRenderer) {}
NS_IMETHOD Run() override {
if (mRenderer && mRenderer->mContext) {
mRenderer->mContext->OnVisibilityChange();
}
return NS_OK;
}
private:
RefPtr<AsyncCanvasRenderer> mRenderer;
};
RefPtr<nsIRunnable> runnable = new Runnable(mAsyncCanvasRenderer);
nsCOMPtr<nsIEventTarget> activeTarget =
mAsyncCanvasRenderer->GetActiveEventTarget();
if (activeTarget) {
activeTarget->Dispatch(runnable, nsIThread::DISPATCH_NORMAL);
}
return;
}
if (mCurrentContext) {
mCurrentContext->OnVisibilityChange();
}
}
void HTMLCanvasElement::OnMemoryPressure() {
if (mOffscreenCanvas) {
class Runnable final : public CancelableRunnable {
public:
explicit Runnable(AsyncCanvasRenderer* aRenderer)
: mozilla::CancelableRunnable("Runnable"), mRenderer(aRenderer) {}
NS_IMETHOD Run() override {
if (mRenderer && mRenderer->mContext) {
mRenderer->mContext->OnMemoryPressure();
}
return NS_OK;
}
private:
RefPtr<AsyncCanvasRenderer> mRenderer;
};
RefPtr<nsIRunnable> runnable = new Runnable(mAsyncCanvasRenderer);
nsCOMPtr<nsIEventTarget> activeTarget =
mAsyncCanvasRenderer->GetActiveEventTarget();
if (activeTarget) {
activeTarget->Dispatch(runnable, nsIThread::DISPATCH_NORMAL);
}
return;
}
if (mCurrentContext) {
mCurrentContext->OnMemoryPressure();
}
}
/* static */
void HTMLCanvasElement::SetAttrFromAsyncCanvasRenderer(
AsyncCanvasRenderer* aRenderer) {
HTMLCanvasElement* element = aRenderer->mHTMLCanvasElement;
if (!element) {
return;
}
if (element->GetWidthHeight() == aRenderer->GetSize()) {
return;
}
gfx::IntSize asyncCanvasSize = aRenderer->GetSize();
ErrorResult rv;
element->SetUnsignedIntAttr(nsGkAtoms::width, asyncCanvasSize.width,
DEFAULT_CANVAS_WIDTH, rv);
if (rv.Failed()) {
NS_WARNING(
"Failed to set width attribute to a canvas element asynchronously.");
}
element->SetUnsignedIntAttr(nsGkAtoms::height, asyncCanvasSize.height,
DEFAULT_CANVAS_HEIGHT, rv);
if (rv.Failed()) {
NS_WARNING(
"Failed to set height attribute to a canvas element asynchronously.");
}
element->mResetLayer = true;
}
/* static */
void HTMLCanvasElement::InvalidateFromAsyncCanvasRenderer(
AsyncCanvasRenderer* aRenderer) {
HTMLCanvasElement* element = aRenderer->mHTMLCanvasElement;
if (!element) {
return;
}
element->InvalidateCanvasContent(nullptr);
}
already_AddRefed<layers::SharedSurfaceTextureClient>
HTMLCanvasElement::GetVRFrame() {
if (GetCurrentContextType() != CanvasContextType::WebGL1 &&
GetCurrentContextType() != CanvasContextType::WebGL2) {
return nullptr;
}
WebGLContext* webgl = static_cast<WebGLContext*>(GetContextAtIndex(0));
if (!webgl) {
return nullptr;
}
return webgl->GetVRFrame();
}
} // namespace dom
} // namespace mozilla
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