1 files changed, 229 insertions, 0 deletions
diff --git a/gfx/ipc/CanvasManagerChild.cpp b/gfx/ipc/CanvasManagerChild.cpp
new file mode 100644
index 0000000000..29f496ab24
--- /dev/null
+++ b/gfx/ipc/CanvasManagerChild.cpp
@@ -0,0 +1,229 @@
+/* -*- 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 "CanvasManagerChild.h"
+#include "mozilla/dom/WorkerPrivate.h"
+#include "mozilla/dom/WorkerRef.h"
+#include "mozilla/gfx/2D.h"
+#include "mozilla/gfx/Swizzle.h"
+#include "mozilla/ipc/Endpoint.h"
+#include "mozilla/layers/CompositorManagerChild.h"
+#include "mozilla/webgpu/WebGPUChild.h"
+
+using namespace mozilla::dom;
+using namespace mozilla::layers;
+
+namespace mozilla::gfx {
+
+// The IPDL actor holds a strong reference to CanvasManagerChild which we use
+// to keep it alive. The owning thread will tell us to close when it is
+// shutdown, either via CanvasManagerChild::Shutdown for the main thread, or
+// via a shutdown callback from IPCWorkerRef for worker threads.
+MOZ_THREAD_LOCAL(CanvasManagerChild*) CanvasManagerChild::sLocalManager;
+
+Atomic<uint32_t> CanvasManagerChild::sNextId(1);
+
+CanvasManagerChild::CanvasManagerChild(uint32_t aId) : mId(aId) {}
+CanvasManagerChild::~CanvasManagerChild() = default;
+
+void CanvasManagerChild::ActorDestroy(ActorDestroyReason aReason) {
+  if (sLocalManager.get() == this) {
+    sLocalManager.set(nullptr);
+  }
+}
+
+void CanvasManagerChild::Destroy() {
+  // The caller has a strong reference. ActorDestroy will clear sLocalManager.
+  Close();
+  mWorkerRef = nullptr;
+}
+
+/* static */ void CanvasManagerChild::Shutdown() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  // The worker threads should destroy their own CanvasManagerChild instances
+  // during their shutdown sequence. We just need to take care of the main
+  // thread. We need to init here because we may have never created a
+  // CanvasManagerChild for the main thread in the first place.
+  if (sLocalManager.init()) {
+    RefPtr<CanvasManagerChild> manager = sLocalManager.get();
+    if (manager) {
+      manager->Destroy();
+    }
+  }
+}
+
+/* static */ bool CanvasManagerChild::CreateParent(
+    ipc::Endpoint<PCanvasManagerParent>&& aEndpoint) {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  CompositorManagerChild* manager = CompositorManagerChild::GetInstance();
+  if (!manager || !manager->CanSend()) {
+    return false;
+  }
+
+  return manager->SendInitCanvasManager(std::move(aEndpoint));
+}
+
+/* static */ CanvasManagerChild* CanvasManagerChild::Get() {
+  if (NS_WARN_IF(!sLocalManager.init())) {
+    return nullptr;
+  }
+
+  CanvasManagerChild* managerWeak = sLocalManager.get();
+  if (managerWeak) {
+    return managerWeak;
+  }
+
+  // We are only used on the main thread, or on worker threads.
+  WorkerPrivate* worker = GetCurrentThreadWorkerPrivate();
+  MOZ_ASSERT_IF(!worker, NS_IsMainThread());
+
+  ipc::Endpoint<PCanvasManagerParent> parentEndpoint;
+  ipc::Endpoint<PCanvasManagerChild> childEndpoint;
+
+  auto compositorPid = CompositorManagerChild::GetOtherPid();
+  if (NS_WARN_IF(!compositorPid)) {
+    return nullptr;
+  }
+
+  nsresult rv = PCanvasManager::CreateEndpoints(
+      compositorPid, base::GetCurrentProcId(), &parentEndpoint, &childEndpoint);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    return nullptr;
+  }
+
+  auto manager = MakeRefPtr<CanvasManagerChild>(sNextId++);
+
+  if (worker) {
+    // The IPCWorkerRef will let us know when the worker is shutting down. This
+    // will let us clear our threadlocal reference and close the actor. We rely
+    // upon an explicit shutdown for the main thread.
+    manager->mWorkerRef = IPCWorkerRef::Create(
+        worker, "CanvasManager", [manager]() { manager->Destroy(); });
+    if (NS_WARN_IF(!manager->mWorkerRef)) {
+      return nullptr;
+    }
+  }
+
+  if (NS_WARN_IF(!childEndpoint.Bind(manager))) {
+    return nullptr;
+  }
+
+  // We can't talk to the compositor process directly from worker threads, but
+  // the main thread can via CompositorManagerChild.
+  if (worker) {
+    worker->DispatchToMainThread(NS_NewRunnableFunction(
+        "CanvasManagerChild::CreateParent",
+        [parentEndpoint = std::move(parentEndpoint)]() {
+          CreateParent(
+              std::move(const_cast<ipc::Endpoint<PCanvasManagerParent>&&>(
+                  parentEndpoint)));
+        }));
+  } else if (NS_WARN_IF(!CreateParent(std::move(parentEndpoint)))) {
+    return nullptr;
+  }
+
+  manager->SendInitialize(manager->Id());
+  sLocalManager.set(manager);
+  return manager;
+}
+
+RefPtr<webgpu::WebGPUChild> CanvasManagerChild::GetWebGPUChild() {
+  if (!mWebGPUChild) {
+    mWebGPUChild = MakeAndAddRef<webgpu::WebGPUChild>();
+    if (!SendPWebGPUConstructor(mWebGPUChild)) {
+      mWebGPUChild = nullptr;
+    }
+  }
+
+  return mWebGPUChild;
+}
+
+already_AddRefed<DataSourceSurface> CanvasManagerChild::GetSnapshot(
+    uint32_t aManagerId, int32_t aProtocolId,
+    const Maybe<RemoteTextureOwnerId>& aOwnerId, SurfaceFormat aFormat,
+    bool aPremultiply, bool aYFlip) {
+  if (!CanSend()) {
+    return nullptr;
+  }
+
+  webgl::FrontBufferSnapshotIpc res;
+  if (!SendGetSnapshot(aManagerId, aProtocolId, aOwnerId, &res)) {
+    return nullptr;
+  }
+
+  if (!res.shmem || !res.shmem->IsReadable()) {
+    return nullptr;
+  }
+
+  auto guard = MakeScopeExit([&] { DeallocShmem(res.shmem.ref()); });
+
+  if (!res.surfSize.x || !res.surfSize.y || res.surfSize.x > INT32_MAX ||
+      res.surfSize.y > INT32_MAX) {
+    return nullptr;
+  }
+
+  IntSize size(res.surfSize.x, res.surfSize.y);
+  CheckedInt32 stride = CheckedInt32(size.width) * sizeof(uint32_t);
+  if (!stride.isValid()) {
+    return nullptr;
+  }
+
+  CheckedInt32 length = stride * size.height;
+  if (!length.isValid() ||
+      size_t(length.value()) != res.shmem->Size<uint8_t>()) {
+    return nullptr;
+  }
+
+  SurfaceFormat format =
+      IsOpaque(aFormat) ? SurfaceFormat::B8G8R8X8 : SurfaceFormat::B8G8R8A8;
+  RefPtr<DataSourceSurface> surface =
+      Factory::CreateDataSourceSurfaceWithStride(size, format, stride.value(),
+                                                 /* aZero */ false);
+  if (!surface) {
+    return nullptr;
+  }
+
+  gfx::DataSourceSurface::ScopedMap map(surface,
+                                        gfx::DataSourceSurface::READ_WRITE);
+  if (!map.IsMapped()) {
+    return nullptr;
+  }
+
+  // The buffer we may readback from the canvas could be R8G8B8A8, not
+  // premultiplied, and/or has its rows iverted. For the general case, we want
+  // surfaces represented as premultiplied B8G8R8A8, with its rows ordered top
+  // to bottom. Given this path is used for screenshots/SurfaceFromElement,
+  // that's the representation we need.
+  if (aYFlip) {
+    if (aPremultiply) {
+      if (!PremultiplyYFlipData(res.shmem->get<uint8_t>(), stride.value(),
+                                aFormat, map.GetData(), map.GetStride(), format,
+                                size)) {
+        return nullptr;
+      }
+    } else {
+      if (!SwizzleYFlipData(res.shmem->get<uint8_t>(), stride.value(), aFormat,
+                            map.GetData(), map.GetStride(), format, size)) {
+        return nullptr;
+      }
+    }
+  } else if (aPremultiply) {
+    if (!PremultiplyData(res.shmem->get<uint8_t>(), stride.value(), aFormat,
+                         map.GetData(), map.GetStride(), format, size)) {
+      return nullptr;
+    }
+  } else {
+    if (!SwizzleData(res.shmem->get<uint8_t>(), stride.value(), aFormat,
+                     map.GetData(), map.GetStride(), format, size)) {
+      return nullptr;
+    }
+  }
+  return surface.forget();
+}
+
+}  // namespace mozilla::gfx