1 files changed, 120 insertions, 0 deletions
diff --git a/gfx/ipc/CanvasRenderThread.cpp b/gfx/ipc/CanvasRenderThread.cpp
new file mode 100644
index 0000000000..5af627d8eb
--- /dev/null
+++ b/gfx/ipc/CanvasRenderThread.cpp
@@ -0,0 +1,120 @@
+/* -*- 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 "CanvasRenderThread.h"
+
+#include "mozilla/BackgroundHangMonitor.h"
+#include "transport/runnable_utils.h"
+
+namespace mozilla::gfx {
+
+static StaticRefPtr<CanvasRenderThread> sCanvasRenderThread;
+static mozilla::BackgroundHangMonitor* sBackgroundHangMonitor;
+#ifdef DEBUG
+static bool sCanvasRenderThreadEverStarted = false;
+#endif
+
+CanvasRenderThread::CanvasRenderThread(RefPtr<nsIThread> aThread)
+    : mThread(std::move(aThread)) {}
+
+CanvasRenderThread::~CanvasRenderThread() {}
+
+// static
+CanvasRenderThread* CanvasRenderThread::Get() { return sCanvasRenderThread; }
+
+// static
+void CanvasRenderThread::Start() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(!sCanvasRenderThread);
+
+#ifdef DEBUG
+  // Check to ensure nobody will try to ever start us more than once during
+  // the process' lifetime (in particular after Stop).
+  MOZ_ASSERT(!sCanvasRenderThreadEverStarted);
+  sCanvasRenderThreadEverStarted = true;
+#endif
+
+  // This is 4M, which is higher than the default 256K.
+  // Increased with bug 1753349 to accommodate the `chromium/5359` branch of
+  // ANGLE, which has large peak stack usage for some pathological shader
+  // compilations.
+  //
+  // Previously increased to 512K to accommodate Mesa in bug 1753340.
+  //
+  // Previously increased to 320K to avoid a stack overflow in the
+  // Intel Vulkan driver initialization in bug 1716120.
+  //
+  // Note: we only override it if it's limited already.
+  const uint32_t stackSize =
+      nsIThreadManager::DEFAULT_STACK_SIZE ? 4096 << 10 : 0;
+
+  RefPtr<nsIThread> thread;
+  nsresult rv = NS_NewNamedThread(
+      "CanvasRenderer", getter_AddRefs(thread),
+      NS_NewRunnableFunction(
+          "CanvasRender::BackgroundHangSetup",
+          []() {
+            sBackgroundHangMonitor = new mozilla::BackgroundHangMonitor(
+                "CanvasRendererBHM",
+                /* Timeout values are powers-of-two to enable us get better
+                   data. 128ms is chosen for transient hangs because 8Hz should
+                   be the minimally acceptable goal for Compositor
+                   responsiveness (normal goal is 60Hz). */
+                128,
+                /* 2048ms is chosen for permanent hangs because it's longer than
+                 * most Compositor hangs seen in the wild, but is short enough
+                 * to not miss getting native hang stacks. */
+                2048);
+            nsCOMPtr<nsIThread> thread = NS_GetCurrentThread();
+            nsThread* nsthread = static_cast<nsThread*>(thread.get());
+            nsthread->SetUseHangMonitor(true);
+            nsthread->SetPriority(nsISupportsPriority::PRIORITY_HIGH);
+          }),
+      {.stackSize = stackSize});
+
+  if (NS_FAILED(rv)) {
+    return;
+  }
+
+  sCanvasRenderThread = new CanvasRenderThread(thread);
+}
+
+// static
+void CanvasRenderThread::ShutDown() {
+  MOZ_ASSERT(NS_IsMainThread());
+  MOZ_ASSERT(sCanvasRenderThread);
+
+  // Null out sCanvasRenderThread before we enter synchronous Shutdown,
+  // from here on we are to be considered shut down for our consumers.
+  nsCOMPtr<nsIThread> oldThread = sCanvasRenderThread->GetCanvasRenderThread();
+  sCanvasRenderThread = nullptr;
+
+  // We do a synchronous shutdown here while spinning the MT event loop.
+  MOZ_ASSERT(oldThread);
+  oldThread->Shutdown();
+}
+
+// static
+bool CanvasRenderThread::IsInCanvasRenderThread() {
+  return sCanvasRenderThread &&
+         sCanvasRenderThread->mThread == NS_GetCurrentThread();
+}
+
+// static
+already_AddRefed<nsIThread> CanvasRenderThread::GetCanvasRenderThread() {
+  nsCOMPtr<nsIThread> thread;
+  if (sCanvasRenderThread) {
+    thread = sCanvasRenderThread->mThread;
+  }
+  return thread.forget();
+}
+
+void CanvasRenderThread::PostRunnable(already_AddRefed<nsIRunnable> aRunnable) {
+  nsCOMPtr<nsIRunnable> runnable = aRunnable;
+  mThread->Dispatch(runnable.forget());
+}
+
+}  // namespace mozilla::gfx