1 files changed, 117 insertions, 0 deletions
diff --git a/dom/canvas/OffscreenCanvasRenderingContext2D.cpp b/dom/canvas/OffscreenCanvasRenderingContext2D.cpp
new file mode 100644
index 0000000000..7481d745ee
--- /dev/null
+++ b/dom/canvas/OffscreenCanvasRenderingContext2D.cpp
@@ -0,0 +1,117 @@
+/* -*- 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 "OffscreenCanvasRenderingContext2D.h"
+#include "mozilla/CycleCollectedJSRuntime.h"
+#include "mozilla/dom/OffscreenCanvasRenderingContext2DBinding.h"
+#include "mozilla/dom/OffscreenCanvas.h"
+
+using namespace mozilla;
+
+namespace mozilla::dom {
+
+NS_IMPL_CYCLE_COLLECTION_INHERITED(OffscreenCanvasRenderingContext2D,
+                                   CanvasRenderingContext2D)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(OffscreenCanvasRenderingContext2D)
+  NS_WRAPPERCACHE_INTERFACE_MAP_ENTRY
+NS_INTERFACE_MAP_END_INHERITING(CanvasRenderingContext2D)
+
+// Need to use NS_DECL_CYCLE_COLLECTION_SKIPPABLE_SCRIPT_HOLDER_CLASS_INHERITED
+// and dummy trace since we're missing some _SKIPPABLE_ macros without
+// SCRIPT_HOLDER.
+NS_IMPL_CYCLE_COLLECTION_TRACE_BEGIN_INHERITED(
+    OffscreenCanvasRenderingContext2D, CanvasRenderingContext2D)
+NS_IMPL_CYCLE_COLLECTION_TRACE_END
+
+NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_BEGIN(OffscreenCanvasRenderingContext2D)
+  return tmp->HasKnownLiveWrapper();
+NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_END
+
+NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_IN_CC_BEGIN(OffscreenCanvasRenderingContext2D)
+  return tmp->HasKnownLiveWrapper();
+NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_IN_CC_END
+
+NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_THIS_BEGIN(OffscreenCanvasRenderingContext2D)
+  return tmp->HasKnownLiveWrapper();
+NS_IMPL_CYCLE_COLLECTION_CAN_SKIP_THIS_END
+
+NS_IMPL_ADDREF_INHERITED(OffscreenCanvasRenderingContext2D,
+                         CanvasRenderingContext2D)
+NS_IMPL_RELEASE_INHERITED(OffscreenCanvasRenderingContext2D,
+                          CanvasRenderingContext2D)
+
+OffscreenCanvasRenderingContext2D::OffscreenCanvasRenderingContext2D(
+    layers::LayersBackend aCompositorBackend)
+    : CanvasRenderingContext2D(aCompositorBackend) {}
+
+OffscreenCanvasRenderingContext2D::~OffscreenCanvasRenderingContext2D() =
+    default;
+
+JSObject* OffscreenCanvasRenderingContext2D::WrapObject(
+    JSContext* aCx, JS::Handle<JSObject*> aGivenProto) {
+  return OffscreenCanvasRenderingContext2D_Binding::Wrap(aCx, this,
+                                                         aGivenProto);
+}
+
+nsIGlobalObject* OffscreenCanvasRenderingContext2D::GetParentObject() const {
+  return mOffscreenCanvas->GetOwnerGlobal();
+}
+
+NS_IMETHODIMP OffscreenCanvasRenderingContext2D::InitializeWithDrawTarget(
+    nsIDocShell* aShell, NotNull<gfx::DrawTarget*> aTarget) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+void OffscreenCanvasRenderingContext2D::Commit(ErrorResult& aRv) {
+  if (!mOffscreenCanvas->IsTransferredFromElement()) {
+    return;
+  }
+
+  mOffscreenCanvas->CommitFrameToCompositor();
+}
+
+void OffscreenCanvasRenderingContext2D::AddZoneWaitingForGC() {
+  JSObject* wrapper = GetWrapperPreserveColor();
+  if (wrapper) {
+    CycleCollectedJSRuntime::Get()->AddZoneWaitingForGC(
+        JS::GetObjectZone(wrapper));
+  }
+}
+
+void OffscreenCanvasRenderingContext2D::AddAssociatedMemory() {
+  JSObject* wrapper = GetWrapperMaybeDead();
+  if (wrapper) {
+    JS::AddAssociatedMemory(wrapper, BindingJSObjectMallocBytes(this),
+                            JS::MemoryUse::DOMBinding);
+  }
+}
+
+void OffscreenCanvasRenderingContext2D::RemoveAssociatedMemory() {
+  JSObject* wrapper = GetWrapperMaybeDead();
+  if (wrapper) {
+    JS::RemoveAssociatedMemory(wrapper, BindingJSObjectMallocBytes(this),
+                               JS::MemoryUse::DOMBinding);
+  }
+}
+
+size_t BindingJSObjectMallocBytes(OffscreenCanvasRenderingContext2D* aContext) {
+  gfx::IntSize size = aContext->GetSize();
+
+  // TODO: Bug 1552137: No memory will be allocated if either dimension is
+  // greater than gfxPrefs::gfx_canvas_max_size(). We should check this here
+  // too.
+
+  CheckedInt<uint32_t> bytes =
+      CheckedInt<uint32_t>(size.width) * size.height * 4;
+  if (!bytes.isValid()) {
+    return 0;
+  }
+
+  return bytes.value();
+}
+
+}  // namespace mozilla::dom