Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 474 insertions, 0 deletions

diff --git a/dom/worklet/WorkletThread.cpp b/dom/worklet/WorkletThread.cpp
new file mode 100644
index 0000000000..c5ad7070b0
--- /dev/null
+++ b/dom/worklet/WorkletThread.cpp
@@ -0,0 +1,474 @@
+/* -*- 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 "WorkletThread.h"
+#include "prthread.h"
+#include "nsContentUtils.h"
+#include "nsCycleCollector.h"
+#include "nsJSEnvironment.h"
+#include "nsJSPrincipals.h"
+#include "mozilla/dom/AtomList.h"
+#include "mozilla/dom/WorkletGlobalScope.h"
+#include "mozilla/ipc/BackgroundChild.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/CycleCollectedJSRuntime.h"
+#include "mozilla/EventQueue.h"
+#include "mozilla/ThreadEventQueue.h"
+#include "js/ContextOptions.h"
+#include "js/Exception.h"
+#include "js/Initialization.h"
+#include "XPCSelfHostedShmem.h"
+
+namespace mozilla::dom {
+
+namespace {
+
+// The size of the worklet runtime heaps in bytes.
+#define WORKLET_DEFAULT_RUNTIME_HEAPSIZE 32 * 1024 * 1024
+
+// The C stack size. We use the same stack size on all platforms for
+// consistency.
+const uint32_t kWorkletStackSize = 256 * sizeof(size_t) * 1024;
+
+// Half the size of the actual C stack, to be safe.
+#define WORKLET_CONTEXT_NATIVE_STACK_LIMIT 128 * sizeof(size_t) * 1024
+
+// Helper functions
+
+bool PreserveWrapper(JSContext* aCx, JS::Handle<JSObject*> aObj) {
+  MOZ_ASSERT(aCx);
+  MOZ_ASSERT(aObj);
+  MOZ_ASSERT(mozilla::dom::IsDOMObject(aObj));
+  return mozilla::dom::TryPreserveWrapper(aObj);
+}
+
+JSObject* Wrap(JSContext* aCx, JS::Handle<JSObject*> aExisting,
+               JS::Handle<JSObject*> aObj) {
+  if (aExisting) {
+    js::Wrapper::Renew(aExisting, aObj,
+                       &js::OpaqueCrossCompartmentWrapper::singleton);
+  }
+
+  return js::Wrapper::New(aCx, aObj,
+                          &js::OpaqueCrossCompartmentWrapper::singleton);
+}
+
+const JSWrapObjectCallbacks WrapObjectCallbacks = {
+    Wrap,
+    nullptr,
+};
+
+}  // namespace
+
+// This classes control CC in the worklet thread.
+
+class WorkletJSRuntime final : public mozilla::CycleCollectedJSRuntime {
+ public:
+  explicit WorkletJSRuntime(JSContext* aCx) : CycleCollectedJSRuntime(aCx) {}
+
+  ~WorkletJSRuntime() override = default;
+
+  virtual void PrepareForForgetSkippable() override {}
+
+  virtual void BeginCycleCollectionCallback(
+      mozilla::CCReason aReason) override {}
+
+  virtual void EndCycleCollectionCallback(
+      CycleCollectorResults& aResults) override {}
+
+  virtual void DispatchDeferredDeletion(bool aContinuation,
+                                        bool aPurge) override {
+    MOZ_ASSERT(!aContinuation);
+    nsCycleCollector_doDeferredDeletion();
+  }
+
+  virtual void CustomGCCallback(JSGCStatus aStatus) override {
+    // nsCycleCollector_collect() requires a cycle collector but
+    // ~WorkletJSContext calls nsCycleCollector_shutdown() and the base class
+    // destructor will trigger a final GC.  The nsCycleCollector_collect()
+    // call can be skipped in this GC as ~CycleCollectedJSContext removes the
+    // context from |this|.
+    if (aStatus == JSGC_END && GetContext()) {
+      nsCycleCollector_collect(CCReason::GC_FINISHED, nullptr);
+    }
+  }
+};
+
+class WorkletJSContext final : public CycleCollectedJSContext {
+ public:
+  WorkletJSContext() {
+    MOZ_ASSERT(!NS_IsMainThread());
+
+    nsCycleCollector_startup();
+  }
+
+  // MOZ_CAN_RUN_SCRIPT_BOUNDARY because otherwise we have to annotate the
+  // SpiderMonkey JS::JobQueue's destructor as MOZ_CAN_RUN_SCRIPT, which is a
+  // bit of a pain.
+  MOZ_CAN_RUN_SCRIPT_BOUNDARY ~WorkletJSContext() override {
+    MOZ_ASSERT(!NS_IsMainThread());
+
+    JSContext* cx = MaybeContext();
+    if (!cx) {
+      return;  // Initialize() must have failed
+    }
+
+    nsCycleCollector_shutdown();
+  }
+
+  WorkletJSContext* GetAsWorkletJSContext() override { return this; }
+
+  CycleCollectedJSRuntime* CreateRuntime(JSContext* aCx) override {
+    return new WorkletJSRuntime(aCx);
+  }
+
+  nsresult Initialize(JSRuntime* aParentRuntime) {
+    MOZ_ASSERT(!NS_IsMainThread());
+
+    nsresult rv = CycleCollectedJSContext::Initialize(
+        aParentRuntime, WORKLET_DEFAULT_RUNTIME_HEAPSIZE);
+    if (NS_WARN_IF(NS_FAILED(rv))) {
+      return rv;
+    }
+
+    JSContext* cx = Context();
+
+    js::SetPreserveWrapperCallbacks(cx, PreserveWrapper, HasReleasedWrapper);
+    JS_InitDestroyPrincipalsCallback(cx, nsJSPrincipals::Destroy);
+    JS_InitReadPrincipalsCallback(cx, nsJSPrincipals::ReadPrincipals);
+    JS_SetWrapObjectCallbacks(cx, &WrapObjectCallbacks);
+    JS_SetFutexCanWait(cx);
+
+    return NS_OK;
+  }
+
+  void DispatchToMicroTask(
+      already_AddRefed<MicroTaskRunnable> aRunnable) override {
+    RefPtr<MicroTaskRunnable> runnable(aRunnable);
+
+    MOZ_ASSERT(!NS_IsMainThread());
+    MOZ_ASSERT(runnable);
+
+    JSContext* cx = Context();
+    MOZ_ASSERT(cx);
+
+#ifdef DEBUG
+    JS::Rooted<JSObject*> global(cx, JS::CurrentGlobalOrNull(cx));
+    MOZ_ASSERT(global);
+#endif
+
+    JS::JobQueueMayNotBeEmpty(cx);
+    GetMicroTaskQueue().push_back(std::move(runnable));
+  }
+
+  bool IsSystemCaller() const override {
+    // Currently no support for special system worklet privileges.
+    return false;
+  }
+
+  void ReportError(JSErrorReport* aReport,
+                   JS::ConstUTF8CharsZ aToStringResult) override;
+
+  uint64_t GetCurrentWorkletWindowID() {
+    JSObject* global = JS::CurrentGlobalOrNull(Context());
+    if (NS_WARN_IF(!global)) {
+      return 0;
+    }
+    nsIGlobalObject* nativeGlobal = xpc::NativeGlobal(global);
+    nsCOMPtr<WorkletGlobalScope> workletGlobal =
+        do_QueryInterface(nativeGlobal);
+    if (NS_WARN_IF(!workletGlobal)) {
+      return 0;
+    }
+    return workletGlobal->Impl()->LoadInfo().InnerWindowID();
+  }
+};
+
+void WorkletJSContext::ReportError(JSErrorReport* aReport,
+                                   JS::ConstUTF8CharsZ aToStringResult) {
+  RefPtr<xpc::ErrorReport> xpcReport = new xpc::ErrorReport();
+  xpcReport->Init(aReport, aToStringResult.c_str(), IsSystemCaller(),
+                  GetCurrentWorkletWindowID());
+  RefPtr<AsyncErrorReporter> reporter = new AsyncErrorReporter(xpcReport);
+
+  JSContext* cx = Context();
+  if (JS_IsExceptionPending(cx)) {
+    JS::ExceptionStack exnStack(cx);
+    if (JS::StealPendingExceptionStack(cx, &exnStack)) {
+      JS::Rooted<JSObject*> stack(cx);
+      JS::Rooted<JSObject*> stackGlobal(cx);
+      xpc::FindExceptionStackForConsoleReport(nullptr, exnStack.exception(),
+                                              exnStack.stack(), &stack,
+                                              &stackGlobal);
+      if (stack) {
+        reporter->SerializeStack(cx, stack);
+      }
+    }
+  }
+
+  NS_DispatchToMainThread(reporter);
+}
+
+// This is the first runnable to be dispatched. It calls the RunEventLoop() so
+// basically everything happens into this runnable. The reason behind this
+// approach is that, when the Worklet is terminated, it must not have any JS in
+// stack, but, because we have CC, nsIThread creates an AutoNoJSAPI object by
+// default. Using this runnable, CC exists only into it.
+class WorkletThread::PrimaryRunnable final : public Runnable {
+ public:
+  explicit PrimaryRunnable(WorkletThread* aWorkletThread)
+      : Runnable("WorkletThread::PrimaryRunnable"),
+        mWorkletThread(aWorkletThread) {
+    MOZ_ASSERT(aWorkletThread);
+    MOZ_ASSERT(NS_IsMainThread());
+  }
+
+  NS_IMETHOD
+  Run() override {
+    mWorkletThread->RunEventLoop();
+    return NS_OK;
+  }
+
+ private:
+  RefPtr<WorkletThread> mWorkletThread;
+};
+
+// This is the last runnable to be dispatched. It calls the TerminateInternal()
+class WorkletThread::TerminateRunnable final : public Runnable {
+ public:
+  explicit TerminateRunnable(WorkletThread* aWorkletThread)
+      : Runnable("WorkletThread::TerminateRunnable"),
+        mWorkletThread(aWorkletThread) {
+    MOZ_ASSERT(aWorkletThread);
+    MOZ_ASSERT(NS_IsMainThread());
+  }
+
+  NS_IMETHOD
+  Run() override {
+    mWorkletThread->TerminateInternal();
+    return NS_OK;
+  }
+
+ private:
+  RefPtr<WorkletThread> mWorkletThread;
+};
+
+WorkletThread::WorkletThread(WorkletImpl* aWorkletImpl)
+    : nsThread(
+          MakeNotNull<ThreadEventQueue*>(MakeUnique<mozilla::EventQueue>()),
+          nsThread::NOT_MAIN_THREAD, {.stackSize = kWorkletStackSize}),
+      mWorkletImpl(aWorkletImpl),
+      mExitLoop(false),
+      mIsTerminating(false) {
+  MOZ_ASSERT(NS_IsMainThread());
+  nsContentUtils::RegisterShutdownObserver(this);
+}
+
+WorkletThread::~WorkletThread() = default;
+
+// static
+already_AddRefed<WorkletThread> WorkletThread::Create(
+    WorkletImpl* aWorkletImpl) {
+  RefPtr<WorkletThread> thread = new WorkletThread(aWorkletImpl);
+  if (NS_WARN_IF(NS_FAILED(thread->Init("DOM Worklet"_ns)))) {
+    return nullptr;
+  }
+
+  RefPtr<PrimaryRunnable> runnable = new PrimaryRunnable(thread);
+  if (NS_WARN_IF(NS_FAILED(thread->DispatchRunnable(runnable.forget())))) {
+    return nullptr;
+  }
+
+  return thread.forget();
+}
+
+nsresult WorkletThread::DispatchRunnable(
+    already_AddRefed<nsIRunnable> aRunnable) {
+  nsCOMPtr<nsIRunnable> runnable(aRunnable);
+  return nsThread::Dispatch(runnable.forget(), NS_DISPATCH_NORMAL);
+}
+
+NS_IMETHODIMP
+WorkletThread::DispatchFromScript(nsIRunnable* aRunnable, uint32_t aFlags) {
+  nsCOMPtr<nsIRunnable> runnable(aRunnable);
+  return Dispatch(runnable.forget(), aFlags);
+}
+
+NS_IMETHODIMP
+WorkletThread::Dispatch(already_AddRefed<nsIRunnable> aRunnable,
+                        uint32_t aFlags) {
+  nsCOMPtr<nsIRunnable> runnable(aRunnable);
+
+  // Worklet only supports asynchronous dispatch.
+  if (NS_WARN_IF(aFlags != NS_DISPATCH_NORMAL)) {
+    return NS_ERROR_UNEXPECTED;
+  }
+
+  return nsThread::Dispatch(runnable.forget(), NS_DISPATCH_NORMAL);
+}
+
+NS_IMETHODIMP
+WorkletThread::DelayedDispatch(already_AddRefed<nsIRunnable>, uint32_t aFlags) {
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+static bool DispatchToEventLoop(void* aClosure,
+                                JS::Dispatchable* aDispatchable) {
+  // This callback may execute either on the worklet thread or a random
+  // JS-internal helper thread.
+
+  // See comment at JS::InitDispatchToEventLoop() below for how we know the
+  // thread is alive.
+  nsIThread* thread = static_cast<nsIThread*>(aClosure);
+
+  nsresult rv = thread->Dispatch(
+      NS_NewRunnableFunction(
+          "WorkletThread::DispatchToEventLoop",
+          [aDispatchable]() {
+            CycleCollectedJSContext* ccjscx = CycleCollectedJSContext::Get();
+            if (!ccjscx) {
+              return;
+            }
+
+            WorkletJSContext* wjc = ccjscx->GetAsWorkletJSContext();
+            if (!wjc) {
+              return;
+            }
+
+            aDispatchable->run(wjc->Context(),
+                               JS::Dispatchable::NotShuttingDown);
+          }),
+      NS_DISPATCH_NORMAL);
+
+  return NS_SUCCEEDED(rv);
+}
+
+// static
+void WorkletThread::EnsureCycleCollectedJSContext(
+    JSRuntime* aParentRuntime, const JS::ContextOptions& aOptions) {
+  CycleCollectedJSContext* ccjscx = CycleCollectedJSContext::Get();
+  if (ccjscx) {
+    MOZ_ASSERT(ccjscx->GetAsWorkletJSContext());
+    return;
+  }
+
+  WorkletJSContext* context = new WorkletJSContext();
+  nsresult rv = context->Initialize(aParentRuntime);
+  if (NS_WARN_IF(NS_FAILED(rv))) {
+    // TODO: error propagation
+    return;
+  }
+
+  JS::ContextOptionsRef(context->Context()) = aOptions;
+
+  JS_SetGCParameter(context->Context(), JSGC_MAX_BYTES, uint32_t(-1));
+
+  // FIXME: JS_SetDefaultLocale
+  // FIXME: JSSettings
+  // FIXME: JS_SetSecurityCallbacks
+  // FIXME: JS::SetAsyncTaskCallbacks
+  // FIXME: JS::SetCTypesActivityCallback
+  // FIXME: JS_SetGCZeal
+
+  // A thread lives strictly longer than its JSRuntime so we can safely
+  // store a raw pointer as the callback's closure argument on the JSRuntime.
+  JS::InitDispatchToEventLoop(context->Context(), DispatchToEventLoop,
+                              NS_GetCurrentThread());
+
+  JS_SetNativeStackQuota(context->Context(),
+                         WORKLET_CONTEXT_NATIVE_STACK_LIMIT);
+
+  // When available, set the self-hosted shared memory to be read, so that we
+  // can decode the self-hosted content instead of parsing it.
+  auto& shm = xpc::SelfHostedShmem::GetSingleton();
+  JS::SelfHostedCache selfHostedContent = shm.Content();
+
+  if (!JS::InitSelfHostedCode(context->Context(), selfHostedContent)) {
+    // TODO: error propagation
+    return;
+  }
+}
+
+void WorkletThread::RunEventLoop() {
+  MOZ_ASSERT(!NS_IsMainThread());
+
+  PR_SetCurrentThreadName("worklet");
+
+  while (!mExitLoop) {
+    MOZ_ALWAYS_TRUE(NS_ProcessNextEvent(this, /* wait: */ true));
+  }
+
+  DeleteCycleCollectedJSContext();
+}
+
+void WorkletThread::Terminate() {
+  MOZ_ASSERT(NS_IsMainThread());
+
+  if (mIsTerminating) {
+    // nsThread::Dispatch() would leak the runnable if the event queue is no
+    // longer accepting runnables.
+    return;
+  }
+
+  mIsTerminating = true;
+
+  nsContentUtils::UnregisterShutdownObserver(this);
+
+  RefPtr<TerminateRunnable> runnable = new TerminateRunnable(this);
+  DispatchRunnable(runnable.forget());
+}
+
+void WorkletThread::TerminateInternal() {
+  MOZ_ASSERT(!CycleCollectedJSContext::Get() || IsOnWorkletThread());
+
+  mExitLoop = true;
+
+  nsCOMPtr<nsIRunnable> runnable = NewRunnableMethod(
+      "WorkletThread::Shutdown", this, &WorkletThread::Shutdown);
+  NS_DispatchToMainThread(runnable);
+}
+
+/* static */
+void WorkletThread::DeleteCycleCollectedJSContext() {
+  CycleCollectedJSContext* ccjscx = CycleCollectedJSContext::Get();
+  if (!ccjscx) {
+    return;
+  }
+
+  // Release any MessagePort kept alive by its ipc actor.
+  mozilla::ipc::BackgroundChild::CloseForCurrentThread();
+
+  WorkletJSContext* workletjscx = ccjscx->GetAsWorkletJSContext();
+  MOZ_ASSERT(workletjscx);
+  delete workletjscx;
+}
+
+/* static */
+bool WorkletThread::IsOnWorkletThread() {
+  CycleCollectedJSContext* ccjscx = CycleCollectedJSContext::Get();
+  return ccjscx && ccjscx->GetAsWorkletJSContext();
+}
+
+/* static */
+void WorkletThread::AssertIsOnWorkletThread() {
+  MOZ_ASSERT(IsOnWorkletThread());
+}
+
+// nsIObserver
+NS_IMETHODIMP
+WorkletThread::Observe(nsISupports* aSubject, const char* aTopic,
+                       const char16_t*) {
+  MOZ_ASSERT(strcmp(aTopic, NS_XPCOM_SHUTDOWN_OBSERVER_ID) == 0);
+
+  // The WorkletImpl will terminate the worklet thread after sending a message
+  // to release worklet thread objects.
+  mWorkletImpl->NotifyWorkletFinished();
+  return NS_OK;
+}
+
+NS_IMPL_ISUPPORTS_INHERITED(WorkletThread, nsThread, nsIObserver)
+
+}  // namespace mozilla::dom