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-rw-r--r--dom/canvas/OffscreenCanvas.cpp562
1 files changed, 562 insertions, 0 deletions
diff --git a/dom/canvas/OffscreenCanvas.cpp b/dom/canvas/OffscreenCanvas.cpp
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--- /dev/null
+++ b/dom/canvas/OffscreenCanvas.cpp
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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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 "OffscreenCanvas.h"
+
+#include "mozilla/Atomics.h"
+#include "mozilla/CheckedInt.h"
+#include "mozilla/dom/BlobImpl.h"
+#include "mozilla/dom/OffscreenCanvasBinding.h"
+#include "mozilla/dom/OffscreenCanvasDisplayHelper.h"
+#include "mozilla/dom/OffscreenCanvasRenderingContext2D.h"
+#include "mozilla/dom/Promise.h"
+#include "mozilla/dom/WorkerPrivate.h"
+#include "mozilla/dom/WorkerRef.h"
+#include "mozilla/dom/WorkerScope.h"
+#include "mozilla/layers/ImageBridgeChild.h"
+#include "mozilla/Telemetry.h"
+#include "mozilla/webgpu/CanvasContext.h"
+#include "CanvasRenderingContext2D.h"
+#include "CanvasUtils.h"
+#include "ClientWebGLContext.h"
+#include "GLContext.h"
+#include "GLScreenBuffer.h"
+#include "ImageBitmap.h"
+#include "ImageBitmapRenderingContext.h"
+#include "nsContentUtils.h"
+#include "nsProxyRelease.h"
+#include "WebGLChild.h"
+
+namespace mozilla::dom {
+
+OffscreenCanvasCloneData::OffscreenCanvasCloneData(
+ OffscreenCanvasDisplayHelper* aDisplay, uint32_t aWidth, uint32_t aHeight,
+ layers::LayersBackend aCompositorBackend, layers::TextureType aTextureType,
+ bool aNeutered, bool aIsWriteOnly, nsIPrincipal* aExpandedReader)
+ : mDisplay(aDisplay),
+ mWidth(aWidth),
+ mHeight(aHeight),
+ mCompositorBackendType(aCompositorBackend),
+ mTextureType(aTextureType),
+ mNeutered(aNeutered),
+ mIsWriteOnly(aIsWriteOnly),
+ mExpandedReader(aExpandedReader) {}
+
+OffscreenCanvasCloneData::~OffscreenCanvasCloneData() {
+ NS_ReleaseOnMainThread("OffscreenCanvasCloneData::mExpandedReader",
+ mExpandedReader.forget());
+}
+
+OffscreenCanvas::OffscreenCanvas(nsIGlobalObject* aGlobal, uint32_t aWidth,
+ uint32_t aHeight)
+ : DOMEventTargetHelper(aGlobal), mWidth(aWidth), mHeight(aHeight) {}
+
+OffscreenCanvas::OffscreenCanvas(
+ nsIGlobalObject* aGlobal, uint32_t aWidth, uint32_t aHeight,
+ layers::LayersBackend aCompositorBackend, layers::TextureType aTextureType,
+ already_AddRefed<OffscreenCanvasDisplayHelper> aDisplay)
+ : DOMEventTargetHelper(aGlobal),
+ mWidth(aWidth),
+ mHeight(aHeight),
+ mCompositorBackendType(aCompositorBackend),
+ mTextureType(aTextureType),
+ mDisplay(aDisplay) {}
+
+OffscreenCanvas::~OffscreenCanvas() {
+ if (mDisplay) {
+ mDisplay->DestroyCanvas();
+ }
+ NS_ReleaseOnMainThread("OffscreenCanvas::mExpandedReader",
+ mExpandedReader.forget());
+}
+
+JSObject* OffscreenCanvas::WrapObject(JSContext* aCx,
+ JS::Handle<JSObject*> aGivenProto) {
+ return OffscreenCanvas_Binding::Wrap(aCx, this, aGivenProto);
+}
+
+/* static */
+already_AddRefed<OffscreenCanvas> OffscreenCanvas::Constructor(
+ const GlobalObject& aGlobal, uint32_t aWidth, uint32_t aHeight,
+ ErrorResult& aRv) {
+ // CanvasRenderingContextHelper::GetWidthHeight wants us to return
+ // an nsIntSize, so make sure that that will work.
+ if (!CheckedInt<int32_t>(aWidth).isValid()) {
+ aRv.ThrowRangeError(
+ nsPrintfCString("OffscreenCanvas width %u is out of range: must be no "
+ "greater than 2147483647.",
+ aWidth));
+ return nullptr;
+ }
+ if (!CheckedInt<int32_t>(aHeight).isValid()) {
+ aRv.ThrowRangeError(
+ nsPrintfCString("OffscreenCanvas height %u is out of range: must be no "
+ "greater than 2147483647.",
+ aHeight));
+ return nullptr;
+ }
+
+ nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(aGlobal.GetAsSupports());
+ RefPtr<OffscreenCanvas> offscreenCanvas =
+ new OffscreenCanvas(global, aWidth, aHeight);
+ return offscreenCanvas.forget();
+}
+
+void OffscreenCanvas::SetWidth(uint32_t aWidth, ErrorResult& aRv) {
+ if (mNeutered) {
+ aRv.ThrowInvalidStateError(
+ "Cannot set width of placeholder canvas transferred to worker.");
+ return;
+ }
+
+ // CanvasRenderingContextHelper::GetWidthHeight wants us to return
+ // an nsIntSize, so make sure that that will work.
+ if (!CheckedInt<int32_t>(aWidth).isValid()) {
+ aRv.ThrowRangeError(
+ nsPrintfCString("OffscreenCanvas width %u is out of range: must be no "
+ "greater than 2147483647.",
+ aWidth));
+ return;
+ }
+
+ mWidth = aWidth;
+ CanvasAttrChanged();
+}
+
+void OffscreenCanvas::SetHeight(uint32_t aHeight, ErrorResult& aRv) {
+ if (mNeutered) {
+ aRv.ThrowInvalidStateError(
+ "Cannot set height of placeholder canvas transferred to worker.");
+ return;
+ }
+
+ // CanvasRenderingContextHelper::GetWidthHeight wants us to return
+ // an nsIntSize, so make sure that that will work.
+ if (!CheckedInt<int32_t>(aHeight).isValid()) {
+ aRv.ThrowRangeError(
+ nsPrintfCString("OffscreenCanvas height %u is out of range: must be no "
+ "greater than 2147483647.",
+ aHeight));
+ return;
+ }
+
+ mHeight = aHeight;
+ CanvasAttrChanged();
+}
+
+void OffscreenCanvas::GetContext(
+ JSContext* aCx, const OffscreenRenderingContextId& aContextId,
+ JS::Handle<JS::Value> aContextOptions,
+ Nullable<OwningOffscreenRenderingContext>& aResult, ErrorResult& aRv) {
+ if (mNeutered) {
+ aResult.SetNull();
+ aRv.ThrowInvalidStateError(
+ "Cannot create context for placeholder canvas transferred to worker.");
+ return;
+ }
+
+ CanvasContextType contextType;
+ switch (aContextId) {
+ case OffscreenRenderingContextId::_2d:
+ contextType = CanvasContextType::OffscreenCanvas2D;
+ break;
+ case OffscreenRenderingContextId::Bitmaprenderer:
+ contextType = CanvasContextType::ImageBitmap;
+ break;
+ case OffscreenRenderingContextId::Webgl:
+ contextType = CanvasContextType::WebGL1;
+ break;
+ case OffscreenRenderingContextId::Webgl2:
+ contextType = CanvasContextType::WebGL2;
+ break;
+ case OffscreenRenderingContextId::Webgpu:
+ contextType = CanvasContextType::WebGPU;
+ break;
+ default:
+ MOZ_ASSERT_UNREACHABLE("Unhandled canvas type!");
+ aResult.SetNull();
+ aRv.Throw(NS_ERROR_NOT_IMPLEMENTED);
+ return;
+ }
+
+ // If we are on a worker, we need to give our OffscreenCanvasDisplayHelper
+ // object access to a worker ref so we can dispatch properly during painting
+ // if we need to flush our contents to its ImageContainer for display.
+ RefPtr<ThreadSafeWorkerRef> workerRef;
+ if (mDisplay) {
+ if (WorkerPrivate* workerPrivate = GetCurrentThreadWorkerPrivate()) {
+ RefPtr<StrongWorkerRef> strongRef = StrongWorkerRef::Create(
+ workerPrivate, "OffscreenCanvas::GetContext",
+ [display = mDisplay]() { display->DestroyCanvas(); });
+ if (NS_WARN_IF(!strongRef)) {
+ aResult.SetNull();
+ aRv.ThrowUnknownError("Worker shutting down");
+ return;
+ }
+
+ workerRef = new ThreadSafeWorkerRef(strongRef);
+ } else {
+ MOZ_ASSERT(NS_IsMainThread());
+ }
+ }
+
+ RefPtr<nsISupports> result = CanvasRenderingContextHelper::GetOrCreateContext(
+ aCx, contextType, aContextOptions, aRv);
+ if (!result) {
+ aResult.SetNull();
+ return;
+ }
+
+ Maybe<int32_t> childId;
+
+ MOZ_ASSERT(mCurrentContext);
+ switch (mCurrentContextType) {
+ case CanvasContextType::OffscreenCanvas2D:
+ aResult.SetValue().SetAsOffscreenCanvasRenderingContext2D() =
+ *static_cast<OffscreenCanvasRenderingContext2D*>(
+ mCurrentContext.get());
+ break;
+ case CanvasContextType::ImageBitmap:
+ aResult.SetValue().SetAsImageBitmapRenderingContext() =
+ *static_cast<ImageBitmapRenderingContext*>(mCurrentContext.get());
+ break;
+ case CanvasContextType::WebGL1:
+ case CanvasContextType::WebGL2: {
+ auto* webgl = static_cast<ClientWebGLContext*>(mCurrentContext.get());
+ WebGLChild* webglChild = webgl->GetChild();
+ if (webglChild) {
+ childId.emplace(webglChild->Id());
+ }
+ aResult.SetValue().SetAsWebGLRenderingContext() = *webgl;
+ break;
+ }
+ case CanvasContextType::WebGPU:
+ aResult.SetValue().SetAsGPUCanvasContext() =
+ *static_cast<webgpu::CanvasContext*>(mCurrentContext.get());
+ break;
+ default:
+ MOZ_ASSERT_UNREACHABLE("Unhandled canvas type!");
+ aResult.SetNull();
+ break;
+ }
+
+ if (mDisplay) {
+ mDisplay->UpdateContext(this, std::move(workerRef), mCurrentContextType,
+ childId);
+ }
+}
+
+already_AddRefed<nsICanvasRenderingContextInternal>
+OffscreenCanvas::CreateContext(CanvasContextType aContextType) {
+ RefPtr<nsICanvasRenderingContextInternal> ret =
+ CanvasRenderingContextHelper::CreateContext(aContextType);
+
+ ret->SetOffscreenCanvas(this);
+ return ret.forget();
+}
+
+void OffscreenCanvas::UpdateDisplayData(
+ const OffscreenCanvasDisplayData& aData) {
+ if (!mDisplay) {
+ return;
+ }
+
+ mPendingUpdate = Some(aData);
+ QueueCommitToCompositor();
+}
+
+void OffscreenCanvas::QueueCommitToCompositor() {
+ if (!mDisplay || !mCurrentContext || mPendingCommit) {
+ // If we already have a commit pending, or we have no bound display/context,
+ // just bail out.
+ return;
+ }
+
+ mPendingCommit = NS_NewCancelableRunnableFunction(
+ "OffscreenCanvas::QueueCommitToCompositor",
+ [self = RefPtr{this}] { self->DequeueCommitToCompositor(); });
+ NS_DispatchToCurrentThread(mPendingCommit);
+}
+
+void OffscreenCanvas::DequeueCommitToCompositor() {
+ MOZ_ASSERT(mPendingCommit);
+ mPendingCommit = nullptr;
+ Maybe<OffscreenCanvasDisplayData> update = std::move(mPendingUpdate);
+ mDisplay->CommitFrameToCompositor(mCurrentContext, mTextureType, update);
+}
+
+void OffscreenCanvas::CommitFrameToCompositor() {
+ if (!mDisplay || !mCurrentContext) {
+ // This offscreen canvas doesn't associate to any HTML canvas element.
+ // So, just bail out.
+ return;
+ }
+
+ if (mPendingCommit) {
+ // We got an explicit commit while waiting for an implicit.
+ mPendingCommit->Cancel();
+ mPendingCommit = nullptr;
+ }
+
+ Maybe<OffscreenCanvasDisplayData> update = std::move(mPendingUpdate);
+ mDisplay->CommitFrameToCompositor(mCurrentContext, mTextureType, update);
+}
+
+OffscreenCanvasCloneData* OffscreenCanvas::ToCloneData() {
+ return new OffscreenCanvasCloneData(mDisplay, mWidth, mHeight,
+ mCompositorBackendType, mTextureType,
+ mNeutered, mIsWriteOnly, mExpandedReader);
+}
+
+already_AddRefed<ImageBitmap> OffscreenCanvas::TransferToImageBitmap(
+ ErrorResult& aRv) {
+ if (mNeutered) {
+ aRv.ThrowInvalidStateError(
+ "Cannot get bitmap from placeholder canvas transferred to worker.");
+ return nullptr;
+ }
+
+ if (!mCurrentContext) {
+ aRv.ThrowInvalidStateError(
+ "Cannot get bitmap from canvas without a context.");
+ return nullptr;
+ }
+
+ RefPtr<ImageBitmap> result =
+ ImageBitmap::CreateFromOffscreenCanvas(GetOwnerGlobal(), *this, aRv);
+ if (!result) {
+ return nullptr;
+ }
+
+ if (mCurrentContext) {
+ mCurrentContext->ResetBitmap();
+ }
+ return result.forget();
+}
+
+already_AddRefed<EncodeCompleteCallback>
+OffscreenCanvas::CreateEncodeCompleteCallback(Promise* aPromise) {
+ // Encoder callback when encoding is complete.
+ class EncodeCallback : public EncodeCompleteCallback {
+ public:
+ explicit EncodeCallback(Promise* aPromise)
+ : mPromise(aPromise), mCanceled(false) {}
+
+ void MaybeInitWorkerRef() {
+ WorkerPrivate* wp = GetCurrentThreadWorkerPrivate();
+ if (wp) {
+ mWorkerRef = WeakWorkerRef::Create(
+ wp, [self = RefPtr{this}]() { self->Cancel(); });
+ if (!mWorkerRef) {
+ Cancel();
+ }
+ }
+ }
+
+ nsresult ReceiveBlobImpl(already_AddRefed<BlobImpl> aBlobImpl) override {
+ RefPtr<BlobImpl> blobImpl = aBlobImpl;
+ mWorkerRef = nullptr;
+
+ if (mPromise) {
+ RefPtr<nsIGlobalObject> global = mPromise->GetGlobalObject();
+ if (NS_WARN_IF(!global) || NS_WARN_IF(!blobImpl)) {
+ mPromise->MaybeReject(NS_ERROR_FAILURE);
+ } else {
+ RefPtr<Blob> blob = Blob::Create(global, blobImpl);
+ if (NS_WARN_IF(!blob)) {
+ mPromise->MaybeReject(NS_ERROR_FAILURE);
+ } else {
+ mPromise->MaybeResolve(blob);
+ }
+ }
+ }
+
+ mPromise = nullptr;
+
+ return NS_OK;
+ }
+
+ bool CanBeDeletedOnAnyThread() override { return mCanceled; }
+
+ void Cancel() {
+ mPromise = nullptr;
+ mWorkerRef = nullptr;
+ mCanceled = true;
+ }
+
+ RefPtr<Promise> mPromise;
+ RefPtr<WeakWorkerRef> mWorkerRef;
+ Atomic<bool> mCanceled;
+ };
+
+ RefPtr<EncodeCallback> p = MakeAndAddRef<EncodeCallback>(aPromise);
+ p->MaybeInitWorkerRef();
+ return p.forget();
+}
+
+already_AddRefed<Promise> OffscreenCanvas::ConvertToBlob(
+ const ImageEncodeOptions& aOptions, ErrorResult& aRv) {
+ // do a trust check if this is a write-only canvas
+ if (mIsWriteOnly) {
+ aRv.ThrowSecurityError("Cannot get blob from write-only canvas.");
+ return nullptr;
+ }
+
+ if (mNeutered) {
+ aRv.ThrowInvalidStateError(
+ "Cannot get blob from placeholder canvas transferred to worker.");
+ return nullptr;
+ }
+
+ if (mWidth == 0 || mHeight == 0) {
+ aRv.ThrowIndexSizeError("Cannot get blob from empty canvas.");
+ return nullptr;
+ }
+
+ nsCOMPtr<nsIGlobalObject> global = GetOwnerGlobal();
+
+ RefPtr<Promise> promise = Promise::Create(global, aRv);
+ if (aRv.Failed()) {
+ return nullptr;
+ }
+
+ nsAutoString type;
+ nsContentUtils::ASCIIToLower(aOptions.mType, type);
+
+ nsAutoString encodeOptions;
+
+ // Only image/jpeg and image/webp support the quality parameter.
+ if (aOptions.mQuality.WasPassed() &&
+ (type.EqualsLiteral("image/jpeg") || type.EqualsLiteral("image/webp"))) {
+ encodeOptions.AppendLiteral("quality=");
+ encodeOptions.AppendInt(NS_lround(aOptions.mQuality.Value() * 100.0));
+ }
+
+ RefPtr<EncodeCompleteCallback> callback =
+ CreateEncodeCompleteCallback(promise);
+ bool usePlaceholder =
+ ShouldResistFingerprinting(RFPTarget::CanvasImageExtractionPrompt);
+ CanvasRenderingContextHelper::ToBlob(callback, type, encodeOptions,
+ /* aUsingCustomOptions */ false,
+ usePlaceholder, aRv);
+ if (aRv.Failed()) {
+ promise->MaybeReject(std::move(aRv));
+ }
+
+ return promise.forget();
+}
+
+already_AddRefed<Promise> OffscreenCanvas::ToBlob(JSContext* aCx,
+ const nsAString& aType,
+ JS::Handle<JS::Value> aParams,
+ ErrorResult& aRv) {
+ // do a trust check if this is a write-only canvas
+ if (mIsWriteOnly) {
+ aRv.ThrowSecurityError("Cannot get blob from write-only canvas.");
+ return nullptr;
+ }
+
+ if (mNeutered) {
+ aRv.ThrowInvalidStateError(
+ "Cannot get blob from placeholder canvas transferred to worker.");
+ return nullptr;
+ }
+
+ if (mWidth == 0 || mHeight == 0) {
+ aRv.ThrowIndexSizeError("Cannot get blob from empty canvas.");
+ return nullptr;
+ }
+
+ nsCOMPtr<nsIGlobalObject> global = GetOwnerGlobal();
+
+ RefPtr<Promise> promise = Promise::Create(global, aRv);
+ if (aRv.Failed()) {
+ return nullptr;
+ }
+
+ RefPtr<EncodeCompleteCallback> callback =
+ CreateEncodeCompleteCallback(promise);
+ bool usePlaceholder =
+ ShouldResistFingerprinting(RFPTarget::CanvasImageExtractionPrompt);
+ CanvasRenderingContextHelper::ToBlob(aCx, callback, aType, aParams,
+ usePlaceholder, aRv);
+
+ return promise.forget();
+}
+
+already_AddRefed<gfx::SourceSurface> OffscreenCanvas::GetSurfaceSnapshot(
+ gfxAlphaType* const aOutAlphaType) {
+ if (!mCurrentContext) {
+ return nullptr;
+ }
+
+ return mCurrentContext->GetSurfaceSnapshot(aOutAlphaType);
+}
+
+void OffscreenCanvas::SetWriteOnly(RefPtr<nsIPrincipal>&& aExpandedReader) {
+ NS_ReleaseOnMainThread("OffscreenCanvas::mExpandedReader",
+ mExpandedReader.forget());
+ mExpandedReader = std::move(aExpandedReader);
+ mIsWriteOnly = true;
+}
+
+bool OffscreenCanvas::CallerCanRead(nsIPrincipal* aPrincipal) const {
+ if (!mIsWriteOnly) {
+ 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);
+}
+
+bool OffscreenCanvas::ShouldResistFingerprinting(RFPTarget aTarget) const {
+ return nsContentUtils::ShouldResistFingerprinting(GetOwnerGlobal(), aTarget);
+}
+
+/* static */
+already_AddRefed<OffscreenCanvas> OffscreenCanvas::CreateFromCloneData(
+ nsIGlobalObject* aGlobal, OffscreenCanvasCloneData* aData) {
+ MOZ_ASSERT(aData);
+ RefPtr<OffscreenCanvas> wc = new OffscreenCanvas(
+ aGlobal, aData->mWidth, aData->mHeight, aData->mCompositorBackendType,
+ aData->mTextureType, aData->mDisplay.forget());
+ if (aData->mNeutered) {
+ wc->SetNeutered();
+ }
+ if (aData->mIsWriteOnly) {
+ wc->SetWriteOnly(std::move(aData->mExpandedReader));
+ }
+ return wc.forget();
+}
+
+/* static */
+bool OffscreenCanvas::PrefEnabledOnWorkerThread(JSContext* aCx,
+ JSObject* aObj) {
+ return NS_IsMainThread() || StaticPrefs::gfx_offscreencanvas_enabled();
+}
+
+NS_IMPL_CYCLE_COLLECTION_INHERITED(OffscreenCanvas, DOMEventTargetHelper,
+ mCurrentContext)
+
+NS_IMPL_ADDREF_INHERITED(OffscreenCanvas, DOMEventTargetHelper)
+NS_IMPL_RELEASE_INHERITED(OffscreenCanvas, DOMEventTargetHelper)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(OffscreenCanvas)
+ NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, EventTarget)
+NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)
+
+} // namespace mozilla::dom
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