1 files changed, 371 insertions, 0 deletions
diff --git a/dom/canvas/OffscreenCanvas.cpp b/dom/canvas/OffscreenCanvas.cpp
new file mode 100644
index 0000000000..0d188c24e3
--- /dev/null
+++ b/dom/canvas/OffscreenCanvas.cpp
@@ -0,0 +1,371 @@
+/* -*- 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/dom/OffscreenCanvasBinding.h"
+#include "mozilla/dom/WorkerPrivate.h"
+#include "mozilla/dom/WorkerScope.h"
+#include "mozilla/layers/AsyncCanvasRenderer.h"
+#include "mozilla/layers/CanvasClient.h"
+#include "mozilla/layers/ImageBridgeChild.h"
+#include "mozilla/Telemetry.h"
+#include "CanvasRenderingContext2D.h"
+#include "CanvasUtils.h"
+#include "GLScreenBuffer.h"
+#include "WebGL1Context.h"
+#include "WebGL2Context.h"
+
+namespace mozilla {
+namespace dom {
+
+OffscreenCanvasCloneData::OffscreenCanvasCloneData(layers::AsyncCanvasRenderer* aRenderer,
+                                                   uint32_t aWidth, uint32_t aHeight,
+                                                   layers::LayersBackend aCompositorBackend,
+                                                   bool aNeutered, bool aIsWriteOnly)
+  : mRenderer(aRenderer)
+  , mWidth(aWidth)
+  , mHeight(aHeight)
+  , mCompositorBackendType(aCompositorBackend)
+  , mNeutered(aNeutered)
+  , mIsWriteOnly(aIsWriteOnly)
+{
+}
+
+OffscreenCanvasCloneData::~OffscreenCanvasCloneData()
+{
+}
+
+OffscreenCanvas::OffscreenCanvas(nsIGlobalObject* aGlobal,
+                                 uint32_t aWidth,
+                                 uint32_t aHeight,
+                                 layers::LayersBackend aCompositorBackend,
+                                 layers::AsyncCanvasRenderer* aRenderer)
+  : DOMEventTargetHelper(aGlobal)
+  , mAttrDirty(false)
+  , mNeutered(false)
+  , mIsWriteOnly(false)
+  , mWidth(aWidth)
+  , mHeight(aHeight)
+  , mCompositorBackendType(aCompositorBackend)
+  , mCanvasRenderer(aRenderer)
+{}
+
+OffscreenCanvas::~OffscreenCanvas()
+{
+  ClearResources();
+}
+
+JSObject*
+OffscreenCanvas::WrapObject(JSContext* aCx,
+                            JS::Handle<JSObject*> aGivenProto)
+{
+  return OffscreenCanvasBinding::Wrap(aCx, this, aGivenProto);
+}
+
+/* static */ already_AddRefed<OffscreenCanvas>
+OffscreenCanvas::Constructor(const GlobalObject& aGlobal,
+                             uint32_t aWidth,
+                             uint32_t aHeight,
+                             ErrorResult& aRv)
+{
+  nsCOMPtr<nsIGlobalObject> global = do_QueryInterface(aGlobal.GetAsSupports());
+  RefPtr<OffscreenCanvas> offscreenCanvas =
+    new OffscreenCanvas(global, aWidth, aHeight,
+                        layers::LayersBackend::LAYERS_NONE, nullptr);
+  return offscreenCanvas.forget();
+}
+
+void
+OffscreenCanvas::ClearResources()
+{
+  if (mCanvasClient) {
+    mCanvasClient->Clear();
+
+    if (mCanvasRenderer) {
+      nsCOMPtr<nsIThread> activeThread = mCanvasRenderer->GetActiveThread();
+      MOZ_RELEASE_ASSERT(activeThread, "GFX: failed to get active thread.");
+      bool current;
+      activeThread->IsOnCurrentThread(&current);
+      MOZ_RELEASE_ASSERT(current, "GFX: active thread is not current thread.");
+      mCanvasRenderer->SetCanvasClient(nullptr);
+      mCanvasRenderer->mContext = nullptr;
+      mCanvasRenderer->mGLContext = nullptr;
+      mCanvasRenderer->ResetActiveThread();
+    }
+
+    mCanvasClient = nullptr;
+  }
+}
+
+already_AddRefed<nsISupports>
+OffscreenCanvas::GetContext(JSContext* aCx,
+                            const nsAString& aContextId,
+                            JS::Handle<JS::Value> aContextOptions,
+                            ErrorResult& aRv)
+{
+  if (mNeutered) {
+    aRv.Throw(NS_ERROR_FAILURE);
+    return nullptr;
+  }
+
+  // We only support WebGL in workers for now
+  CanvasContextType contextType;
+  if (!CanvasUtils::GetCanvasContextType(aContextId, &contextType)) {
+    aRv.Throw(NS_ERROR_NOT_IMPLEMENTED);
+    return nullptr;
+  }
+
+  if (!(contextType == CanvasContextType::WebGL1 ||
+        contextType == CanvasContextType::WebGL2 ||
+        contextType == CanvasContextType::ImageBitmap))
+  {
+    aRv.Throw(NS_ERROR_NOT_IMPLEMENTED);
+    return nullptr;
+  }
+
+  already_AddRefed<nsISupports> result =
+    CanvasRenderingContextHelper::GetContext(aCx,
+                                             aContextId,
+                                             aContextOptions,
+                                             aRv);
+
+  if (!mCurrentContext) {
+    return nullptr;
+  }
+
+  if (mCanvasRenderer) {
+    if (contextType == CanvasContextType::WebGL1 ||
+        contextType == CanvasContextType::WebGL2) {
+      WebGLContext* webGL = static_cast<WebGLContext*>(mCurrentContext.get());
+      gl::GLContext* gl = webGL->GL();
+      mCanvasRenderer->mContext = mCurrentContext;
+      mCanvasRenderer->SetActiveThread();
+      mCanvasRenderer->mGLContext = gl;
+      mCanvasRenderer->SetIsAlphaPremultiplied(webGL->IsPremultAlpha() || !gl->Caps().alpha);
+
+      if (RefPtr<ImageBridgeChild> imageBridge = ImageBridgeChild::GetSingleton()) {
+        TextureFlags flags = TextureFlags::ORIGIN_BOTTOM_LEFT;
+        mCanvasClient = imageBridge->CreateCanvasClient(CanvasClient::CanvasClientTypeShSurf, flags);
+        mCanvasRenderer->SetCanvasClient(mCanvasClient);
+
+        gl::GLScreenBuffer* screen = gl->Screen();
+        gl::SurfaceCaps caps = screen->mCaps;
+        auto forwarder = mCanvasClient->GetForwarder();
+
+        UniquePtr<gl::SurfaceFactory> factory =
+          gl::GLScreenBuffer::CreateFactory(gl, caps, forwarder, flags);
+
+        if (factory)
+          screen->Morph(Move(factory));
+      }
+    }
+  }
+
+  return result;
+}
+
+already_AddRefed<nsICanvasRenderingContextInternal>
+OffscreenCanvas::CreateContext(CanvasContextType aContextType)
+{
+  RefPtr<nsICanvasRenderingContextInternal> ret =
+    CanvasRenderingContextHelper::CreateContext(aContextType);
+
+  ret->SetOffscreenCanvas(this);
+  return ret.forget();
+}
+
+void
+OffscreenCanvas::CommitFrameToCompositor()
+{
+  if (!mCanvasRenderer) {
+    // This offscreen canvas doesn't associate to any HTML canvas element.
+    // So, just bail out.
+    return;
+  }
+
+  // The attributes has changed, we have to notify main
+  // thread to change canvas size.
+  if (mAttrDirty) {
+    if (mCanvasRenderer) {
+      mCanvasRenderer->SetWidth(mWidth);
+      mCanvasRenderer->SetHeight(mHeight);
+      mCanvasRenderer->NotifyElementAboutAttributesChanged();
+    }
+    mAttrDirty = false;
+  }
+
+  if (mCurrentContext) {
+    static_cast<WebGLContext*>(mCurrentContext.get())->PresentScreenBuffer();
+  }
+
+  if (mCanvasRenderer && mCanvasRenderer->mGLContext) {
+    mCanvasRenderer->NotifyElementAboutInvalidation();
+    ImageBridgeChild::GetSingleton()->
+      UpdateAsyncCanvasRenderer(mCanvasRenderer);
+  }
+}
+
+OffscreenCanvasCloneData*
+OffscreenCanvas::ToCloneData()
+{
+  return new OffscreenCanvasCloneData(mCanvasRenderer, mWidth, mHeight,
+                                      mCompositorBackendType, mNeutered, mIsWriteOnly);
+}
+
+already_AddRefed<ImageBitmap>
+OffscreenCanvas::TransferToImageBitmap()
+{
+  ErrorResult rv;
+  nsCOMPtr<nsIGlobalObject> globalObject = GetGlobalObject();
+  RefPtr<ImageBitmap> result = ImageBitmap::CreateFromOffscreenCanvas(globalObject, *this, rv);
+
+  // Clear the content.
+  if ((mCurrentContextType == CanvasContextType::WebGL1 ||
+       mCurrentContextType == CanvasContextType::WebGL2))
+  {
+    WebGLContext* webGL = static_cast<WebGLContext*>(mCurrentContext.get());
+    webGL->ClearScreen();
+  }
+
+  return result.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.Throw(NS_ERROR_DOM_SECURITY_ERR);
+    return nullptr;
+  }
+
+  nsCOMPtr<nsIGlobalObject> global = GetGlobalObject();
+
+  RefPtr<Promise> promise = Promise::Create(global, aRv);
+  if (aRv.Failed()) {
+    return nullptr;
+  }
+
+  // Encoder callback when encoding is complete.
+  class EncodeCallback : public EncodeCompleteCallback
+  {
+  public:
+    EncodeCallback(nsIGlobalObject* aGlobal, Promise* aPromise)
+      : mGlobal(aGlobal)
+      , mPromise(aPromise) {}
+
+    // This is called on main thread.
+    nsresult ReceiveBlob(already_AddRefed<Blob> aBlob)
+    {
+      RefPtr<Blob> blob = aBlob;
+
+      ErrorResult rv;
+      uint64_t size = blob->GetSize(rv);
+      if (rv.Failed()) {
+        rv.SuppressException();
+      } else {
+        AutoJSAPI jsapi;
+        if (jsapi.Init(mGlobal)) {
+          JS_updateMallocCounter(jsapi.cx(), size);
+        }
+      }
+
+      if (mPromise) {
+        RefPtr<Blob> newBlob = Blob::Create(mGlobal, blob->Impl());
+        mPromise->MaybeResolve(newBlob);
+      }
+
+      mGlobal = nullptr;
+      mPromise = nullptr;
+
+      return rv.StealNSResult();
+    }
+
+    nsCOMPtr<nsIGlobalObject> mGlobal;
+    RefPtr<Promise> mPromise;
+  };
+
+  RefPtr<EncodeCompleteCallback> callback =
+    new EncodeCallback(global, promise);
+
+  CanvasRenderingContextHelper::ToBlob(aCx, global,
+                                       callback, aType, aParams, aRv);
+
+  return promise.forget();
+}
+
+already_AddRefed<gfx::SourceSurface>
+OffscreenCanvas::GetSurfaceSnapshot(bool* aPremultAlpha)
+{
+  if (!mCurrentContext) {
+    return nullptr;
+  }
+
+  return mCurrentContext->GetSurfaceSnapshot(aPremultAlpha);
+}
+
+nsCOMPtr<nsIGlobalObject>
+OffscreenCanvas::GetGlobalObject()
+{
+  if (NS_IsMainThread()) {
+    return GetParentObject();
+  }
+
+  dom::workers::WorkerPrivate* workerPrivate =
+    dom::workers::GetCurrentThreadWorkerPrivate();
+  return workerPrivate->GlobalScope();
+}
+
+/* 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->mRenderer);
+  if (aData->mNeutered) {
+    wc->SetNeutered();
+  }
+  return wc.forget();
+}
+
+/* static */ bool
+OffscreenCanvas::PrefEnabled(JSContext* aCx, JSObject* aObj)
+{
+  if (NS_IsMainThread()) {
+    return Preferences::GetBool("gfx.offscreencanvas.enabled");
+  } else {
+    WorkerPrivate* workerPrivate = GetWorkerPrivateFromContext(aCx);
+    MOZ_ASSERT(workerPrivate);
+    return workerPrivate->OffscreenCanvasEnabled();
+  }
+}
+
+/* static */ bool
+OffscreenCanvas::PrefEnabledOnWorkerThread(JSContext* aCx, JSObject* aObj)
+{
+  if (NS_IsMainThread()) {
+    return true;
+  }
+
+  return PrefEnabled(aCx, aObj);
+}
+
+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_INHERITED(OffscreenCanvas)
+  NS_INTERFACE_MAP_ENTRY(nsISupports)
+NS_INTERFACE_MAP_END_INHERITING(DOMEventTargetHelper)
+
+} // namespace dom
+} // namespace mozilla