Files
tubestation/gfx/ipc/CanvasManagerParent.cpp
Lee Salzman 1d18f4b2f5 Bug 1938053 - Accelerate canvas drawImage of a WebGL context. r=aosmond
Accelerated Canvas2D and WebGL both live within the GPU process and run within
the same thread. We want to avoid any kind of readbacks from the GPU process
to the content process when doing a drawImage of a WebGL context to an AC2D
canvas.

To achieve this, we pause the AC2D recording translation with an AwaitTranslationSync
event identified by a sync-id. Then we send a request over IPDL to snapshot the
WebGL context while this pause is ongoing via a SnapshotExternalCanvas IPDL message,
which uses the sync-id to identify the snapshot safely in a table of such external
snapshots and force translation to resume. Finally, we send a ResolveExternalSnapshot
event within the recording stream to lookup the snapshot based on the sync-id and
assign it an alias that can be used within the recording stream playback for drawImage.

The sync-id mechanism acts as a sequenced fence so that multiple SnapshotExternalCanvas
requests can be encountered simultaneously from IPDL without confusing the recording
playback.

Differential Revision: https://phabricator.services.mozilla.com/D243399
2025-04-15 16:44:20 +00:00

274 lines
8.5 KiB
C++

/* -*- 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 "CanvasManagerParent.h"
#include "gfxPlatform.h"
#include "mozilla/dom/WebGLParent.h"
#include "mozilla/gfx/CanvasRenderThread.h"
#include "mozilla/gfx/gfxVars.h"
#include "mozilla/gfx/GPUParent.h"
#include "mozilla/ipc/Endpoint.h"
#include "mozilla/layers/CanvasTranslator.h"
#include "mozilla/layers/CompositorThread.h"
#include "mozilla/layers/ISurfaceAllocator.h"
#include "mozilla/layers/SharedSurfacesParent.h"
#include "mozilla/StaticPrefs_gfx.h"
#include "mozilla/StaticPrefs_webgl.h"
#include "mozilla/webgpu/WebGPUParent.h"
#include "nsIThread.h"
#include "nsThreadUtils.h"
namespace mozilla::gfx {
MOZ_RUNINIT CanvasManagerParent::ManagerSet CanvasManagerParent::sManagers;
/* static */ void CanvasManagerParent::Init(
Endpoint<PCanvasManagerParent>&& aEndpoint,
layers::SharedSurfacesHolder* aSharedSurfacesHolder,
const dom::ContentParentId& aContentId) {
MOZ_ASSERT(layers::CompositorThreadHolder::IsInCompositorThread());
auto manager =
MakeRefPtr<CanvasManagerParent>(aSharedSurfacesHolder, aContentId);
nsCOMPtr<nsIThread> owningThread =
gfx::CanvasRenderThread::GetCanvasRenderThread();
MOZ_ASSERT(owningThread);
owningThread->Dispatch(NewRunnableMethod<Endpoint<PCanvasManagerParent>&&>(
"CanvasManagerParent::Bind", manager, &CanvasManagerParent::Bind,
std::move(aEndpoint)));
}
/* static */ void CanvasManagerParent::Shutdown() {
MOZ_ASSERT(NS_IsMainThread());
nsCOMPtr<nsIThread> owningThread =
gfx::CanvasRenderThread::GetCanvasRenderThread();
MOZ_ASSERT(owningThread);
NS_DispatchAndSpinEventLoopUntilComplete(
"CanvasManagerParent::Shutdown"_ns, owningThread,
NS_NewRunnableFunction("CanvasManagerParent::Shutdown", []() -> void {
CanvasManagerParent::ShutdownInternal();
}));
}
/* static */ void CanvasManagerParent::ShutdownInternal() {
nsTArray<RefPtr<CanvasManagerParent>> actors(sManagers.Count());
// Do a copy since Close will remove the entry from the set.
for (const auto& actor : sManagers) {
actors.AppendElement(actor);
}
for (auto const& actor : actors) {
actor->Close();
}
}
/* static */ void CanvasManagerParent::DisableRemoteCanvas() {
NS_DispatchToMainThread(
NS_NewRunnableFunction("CanvasManagerParent::DisableRemoteCanvas", [] {
if (XRE_IsGPUProcess()) {
GPUParent::GetSingleton()->NotifyDisableRemoteCanvas();
} else {
gfxPlatform::DisableRemoteCanvas();
}
}));
if (CanvasRenderThread::IsInCanvasRenderThread()) {
DisableRemoteCanvasInternal();
return;
}
CanvasRenderThread::Dispatch(NS_NewRunnableFunction(
"CanvasManagerParent::DisableRemoteCanvas",
[] { CanvasManagerParent::DisableRemoteCanvasInternal(); }));
}
/* static */ void CanvasManagerParent::DisableRemoteCanvasInternal() {
MOZ_ASSERT(CanvasRenderThread::IsInCanvasRenderThread());
AutoTArray<RefPtr<layers::CanvasTranslator>, 16> actors;
for (const auto& manager : sManagers) {
for (const auto& canvas : manager->ManagedPCanvasParent()) {
actors.AppendElement(static_cast<layers::CanvasTranslator*>(canvas));
}
}
for (const auto& actor : actors) {
Unused << NS_WARN_IF(!actor->SendDeactivate());
}
}
CanvasManagerParent::CanvasManagerParent(
layers::SharedSurfacesHolder* aSharedSurfacesHolder,
const dom::ContentParentId& aContentId)
: mSharedSurfacesHolder(aSharedSurfacesHolder), mContentId(aContentId) {}
CanvasManagerParent::~CanvasManagerParent() = default;
void CanvasManagerParent::Bind(Endpoint<PCanvasManagerParent>&& aEndpoint) {
if (!aEndpoint.Bind(this)) {
NS_WARNING("Failed to bind CanvasManagerParent!");
return;
}
#ifdef DEBUG
for (CanvasManagerParent* i : sManagers) {
MOZ_ASSERT_IF(i->mContentId == mContentId,
i->OtherPidMaybeInvalid() == OtherPidMaybeInvalid());
}
#endif
sManagers.Insert(this);
}
void CanvasManagerParent::ActorDestroy(ActorDestroyReason aWhy) {
sManagers.Remove(this);
}
already_AddRefed<dom::PWebGLParent> CanvasManagerParent::AllocPWebGLParent() {
if (NS_WARN_IF(!gfxVars::AllowWebglOop() &&
!StaticPrefs::webgl_out_of_process_force())) {
MOZ_ASSERT_UNREACHABLE("AllocPWebGLParent without remote WebGL");
return nullptr;
}
return MakeAndAddRef<dom::WebGLParent>(mSharedSurfacesHolder, mContentId);
}
already_AddRefed<webgpu::PWebGPUParent>
CanvasManagerParent::AllocPWebGPUParent() {
if (NS_WARN_IF(!gfxVars::AllowWebGPU())) {
MOZ_ASSERT_UNREACHABLE("AllocPWebGPUParent without WebGPU");
return nullptr;
}
return MakeAndAddRef<webgpu::WebGPUParent>();
}
mozilla::ipc::IPCResult CanvasManagerParent::RecvInitialize(
const uint32_t& aId) {
if (!aId) {
return IPC_FAIL(this, "invalid id");
}
if (mId) {
return IPC_FAIL(this, "already initialized");
}
mId = aId;
return IPC_OK();
}
already_AddRefed<layers::PCanvasParent>
CanvasManagerParent::AllocPCanvasParent() {
if (NS_WARN_IF(!gfx::gfxVars::RemoteCanvasEnabled() &&
!gfx::gfxVars::UseAcceleratedCanvas2D())) {
MOZ_ASSERT_UNREACHABLE("AllocPCanvasParent without remote canvas");
return nullptr;
}
if (NS_WARN_IF(!mId)) {
MOZ_ASSERT_UNREACHABLE("AllocPCanvasParent without ID");
return nullptr;
}
return MakeAndAddRef<layers::CanvasTranslator>(mSharedSurfacesHolder,
mContentId, mId);
}
mozilla::ipc::IPCResult CanvasManagerParent::RecvGetSnapshot(
const uint32_t& aManagerId, const int32_t& aProtocolId,
const Maybe<RemoteTextureOwnerId>& aOwnerId,
const Maybe<RawId>& aCommandEncoderId,
webgl::FrontBufferSnapshotIpc* aResult) {
if (!aManagerId) {
return IPC_FAIL(this, "invalid id");
}
IProtocol* actor = nullptr;
for (CanvasManagerParent* i : sManagers) {
if (i->mContentId == mContentId && i->mId == aManagerId) {
actor = i->Lookup(aProtocolId);
break;
}
}
if (!actor) {
return IPC_FAIL(this, "invalid actor");
}
if (actor->GetSide() != mozilla::ipc::Side::ParentSide) {
return IPC_FAIL(this, "unsupported actor");
}
webgl::FrontBufferSnapshotIpc buffer;
switch (actor->GetProtocolId()) {
case ProtocolId::PWebGLMsgStart: {
RefPtr<dom::WebGLParent> webgl = static_cast<dom::WebGLParent*>(actor);
mozilla::ipc::IPCResult rv = webgl->GetFrontBufferSnapshot(&buffer, this);
if (!rv) {
return rv;
}
} break;
case ProtocolId::PWebGPUMsgStart: {
RefPtr<webgpu::WebGPUParent> webgpu =
static_cast<webgpu::WebGPUParent*>(actor);
IntSize size;
if (aOwnerId.isNothing()) {
return IPC_FAIL(this, "invalid OwnerId");
}
if (aCommandEncoderId.isNothing()) {
return IPC_FAIL(this, "invalid CommandEncoderId");
}
uint32_t stride = 0;
mozilla::ipc::IPCResult rv = webgpu->GetFrontBufferSnapshot(
this, *aOwnerId, *aCommandEncoderId, buffer.shmem, size, stride);
if (!rv) {
return rv;
}
buffer.surfSize.x = static_cast<uint32_t>(size.width);
buffer.surfSize.y = static_cast<uint32_t>(size.height);
buffer.byteStride = stride;
} break;
default:
return IPC_FAIL(this, "unsupported protocol");
}
*aResult = std::move(buffer);
return IPC_OK();
}
/* static */ mozilla::ipc::IProtocol* CanvasManagerParent::GetCanvasActor(
dom::ContentParentId aContentId, uint32_t aManagerId, int32_t aCanvasId) {
IProtocol* actor = nullptr;
for (CanvasManagerParent* i : sManagers) {
if (i->mContentId == aContentId && i->mId == aManagerId) {
actor = i->Lookup(aCanvasId);
break;
}
}
return actor;
}
/* static */ already_AddRefed<DataSourceSurface>
CanvasManagerParent::GetCanvasSurface(dom::ContentParentId aContentId,
uint32_t aManagerId, int32_t aCanvasId,
uintptr_t aSurfaceId) {
IProtocol* actor = GetCanvasActor(aContentId, aManagerId, aCanvasId);
if (!actor) {
return nullptr;
}
switch (actor->GetProtocolId()) {
case ProtocolId::PCanvasMsgStart:
return static_cast<layers::CanvasTranslator*>(actor)->WaitForSurface(
aSurfaceId);
default:
MOZ_ASSERT_UNREACHABLE("Unsupported protocol");
break;
}
return nullptr;
}
} // namespace mozilla::gfx