commit 916c78a0a56a38763077634cd492cfdcb2e37b81 Author: Kathy Brade brade@pearlcrescent.com Date: Mon Mar 28 17:04:07 2016 -0400

fixup! Bug #6253: Add canvas image extraction prompt.

Place Canvas MediaStream behind site permission prompt (#15640). --- dom/html/HTMLCanvasElement.cpp | 46 ++++++++++++++++++++++++++++++++---------- dom/html/HTMLCanvasElement.h | 5 ++++- 2 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/dom/html/HTMLCanvasElement.cpp b/dom/html/HTMLCanvasElement.cpp index 314bf48..dd74d9f 100644 --- a/dom/html/HTMLCanvasElement.cpp +++ b/dom/html/HTMLCanvasElement.cpp @@ -59,8 +59,10 @@ class RequestedFrameRefreshObserver : public nsARefreshObserver

public: RequestedFrameRefreshObserver(HTMLCanvasElement* const aOwningElement, - nsRefreshDriver* aRefreshDriver) + nsRefreshDriver* aRefreshDriver, + bool aReturnPlaceholderData) : mRegistered(false), + mReturnPlaceholderData(aReturnPlaceholderData), mOwningElement(aOwningElement), mRefreshDriver(aRefreshDriver) { @@ -68,7 +70,8 @@ public: }

static already_AddRefed<DataSourceSurface> - CopySurface(const RefPtr<SourceSurface>& aSurface) + CopySurface(const RefPtr<SourceSurface>& aSurface, + bool aReturnPlaceholderData) { RefPtr<DataSourceSurface> data = aSurface->GetDataSurface(); if (!data) { @@ -97,12 +100,23 @@ public: MOZ_ASSERT(data->GetSize() == copy->GetSize()); MOZ_ASSERT(data->GetFormat() == copy->GetFormat());

- memcpy(write.GetData(), read.GetData(), - write.GetStride() * copy->GetSize().height); + 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()); @@ -128,8 +142,8 @@ public: return; }

- RefPtr<DataSourceSurface> copy = CopySurface(snapshot); - + RefPtr<DataSourceSurface> copy = CopySurface(snapshot, + mReturnPlaceholderData); mOwningElement->SetFrameCapture(copy.forget()); mOwningElement->MarkContextCleanForFrameCapture(); } @@ -177,6 +191,7 @@ private: }

bool mRegistered; + bool mReturnPlaceholderData; HTMLCanvasElement* const mOwningElement; RefPtr<nsRefreshDriver> mRefreshDriver; }; @@ -682,8 +697,13 @@ HTMLCanvasElement::CaptureStream(const Optional<double>& aFrameRate, return nullptr; }

+ // 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()); stream->CreateOwnDOMTrack(videoTrackId, MediaSegment::VIDEO); - RegisterFrameCaptureListener(stream->FrameCaptureListener()); + RegisterFrameCaptureListener(stream->FrameCaptureListener(), usePlaceholder); return stream.forget(); }

@@ -693,7 +713,7 @@ HTMLCanvasElement::ExtractData(JSContext* aCx, const nsAString& aOptions, nsIInputStream** aStream) { - // Check site-speciifc permission and display prompt if appropriate. + // Check site-specific permission and display prompt if appropriate. // If no permission, return all-white, opaque image data. bool usePlaceholder = !CanvasUtils::IsImageExtractionAllowed(OwnerDoc(), aCx); return ImageEncoder::ExtractData(aType, @@ -766,7 +786,7 @@ HTMLCanvasElement::ToBlob(JSContext* aCx, nsCOMPtr<nsIGlobalObject> global = OwnerDoc()->GetScopeObject(); MOZ_ASSERT(global);

- // Check site-speciifc permission and display prompt if appropriate. + // Check site-specific permission and display prompt if appropriate. // If no permission, return all-white, opaque image data. bool usePlaceholder = !CanvasUtils::IsImageExtractionAllowed(OwnerDoc(), aCx); CanvasRenderingContextHelper::ToBlob(aCx, global, aCallback, aType, @@ -1131,7 +1151,8 @@ HTMLCanvasElement::IsContextCleanForFrameCapture() }

void -HTMLCanvasElement::RegisterFrameCaptureListener(FrameCaptureListener* aListener) +HTMLCanvasElement::RegisterFrameCaptureListener(FrameCaptureListener* aListener, + bool aReturnPlaceholderData) { WeakPtr<FrameCaptureListener> listener = aListener;

@@ -1158,7 +1179,10 @@ HTMLCanvasElement::RegisterFrameCaptureListener(FrameCaptureListener* aListener) MOZ_RELEASE_ASSERT(driver);

mRequestedFrameRefreshObserver = - new RequestedFrameRefreshObserver(this, driver); + new RequestedFrameRefreshObserver(this, driver, aReturnPlaceholderData); + } else { + mRequestedFrameRefreshObserver->SetReturnPlaceholderData( + aReturnPlaceholderData); }

mRequestedFrameRefreshObserver->Register(); diff --git a/dom/html/HTMLCanvasElement.h b/dom/html/HTMLCanvasElement.h index 542f11b..6ed7bbd 100644 --- a/dom/html/HTMLCanvasElement.h +++ b/dom/html/HTMLCanvasElement.h @@ -263,8 +263,11 @@ public: * The registered FrameCaptureListeners are stored as WeakPtrs, thus it's the * caller's responsibility to keep them alive. Once a registered * FrameCaptureListener is destroyed it will be automatically deregistered. + * If aReturnPlaceholderData is true, white data is captured instead of the + * actual canvas contents. */ - void RegisterFrameCaptureListener(FrameCaptureListener* aListener); + void RegisterFrameCaptureListener(FrameCaptureListener* aListener, + bool aReturnPlaceholderData);

/* * Returns true when there is at least one registered FrameCaptureListener