Backed out changeset cd49a95d80fd (bug 1851938) for causing leackcheck failures

js/xpconnect/loader/ChromeScriptLoader.cpp

@@ -24,9 +24,7 @@
 #include "mozilla/AlreadyAddRefed.h"  // already_AddRefed
 #include "mozilla/Assertions.h"       // MOZ_ASSERT
 #include "mozilla/Attributes.h"
-#include "mozilla/ClearOnShutdown.h"  // RunOnShutdown
-#include "mozilla/EventQueue.h"       // EventQueuePriority
-#include "mozilla/Mutex.h"
+#include "mozilla/EventQueue.h"  // EventQueuePriority
 #include "mozilla/SchedulerGroup.h"
 #include "mozilla/StaticPrefs_javascript.h"
 #include "mozilla/dom/ChromeUtils.h"
@@ -35,9 +33,7 @@
 #include "mozilla/HoldDropJSObjects.h"
 #include "mozilla/RefPtr.h"          // RefPtr
 #include "mozilla/TaskController.h"  // TaskController, Task
-#include "mozilla/ThreadSafety.h"    // MOZ_GUARDED_BY
-#include "mozilla/Utf8.h"            // Utf8Unit
-#include "mozilla/Vector.h"
+#include "mozilla//Utf8.h"           // Utf8Unit
 #include "nsCCUncollectableMarker.h"
 #include "nsCycleCollectionParticipant.h"
 
@@ -46,59 +42,19 @@ using namespace mozilla;
 using namespace mozilla::dom;
 
 class AsyncScriptCompileTask final : public Task {
-  static mozilla::Mutex sOngoingTasksMutex;
-  static Vector<AsyncScriptCompileTask*> sOngoingTasks
-      MOZ_GUARDED_BY(sOngoingTasksMutex);
-  static bool sIsShutdownRegistered;
-
-  // Compilation tasks should be cancelled before calling JS_ShutDown, in order
-  // to avoid keeping JS::Stencil and SharedImmutableString pointers alive
-  // beyond it.
-  //
-  // Cancel all ongoing tasks at ShutdownPhase::XPCOMShutdownFinal, which
-  // happens before calling JS_ShutDown.
-  static bool RegisterTask(AsyncScriptCompileTask* aTask) {
-    MOZ_ASSERT(NS_IsMainThread());
-
-    if (!sIsShutdownRegistered) {
-      sIsShutdownRegistered = true;
-
-      RunOnShutdown([] {
-        MutexAutoLock lock(sOngoingTasksMutex);
-        for (auto* task : sOngoingTasks) {
-          task->Cancel();
-        }
-      });
-    }
-
-    MutexAutoLock lock(sOngoingTasksMutex);
-    return sOngoingTasks.append(aTask);
-  }
-
-  static void UnregisterTask(const AsyncScriptCompileTask* aTask) {
-    MutexAutoLock lock(sOngoingTasksMutex);
-    sOngoingTasks.eraseIfEqual(aTask);
-  }
-
  public:
   explicit AsyncScriptCompileTask(JS::SourceText<Utf8Unit>&& aSrcBuf)
       : Task(Kind::OffMainThreadOnly, EventQueuePriority::Normal),
         mOptions(JS::OwningCompileOptions::ForFrontendContext()),
-        mSrcBuf(std::move(aSrcBuf)),
-        mMutex("AsyncScriptCompileTask") {}
+        mSrcBuf(std::move(aSrcBuf)) {}
 
   ~AsyncScriptCompileTask() {
     if (mFrontendContext) {
       JS::DestroyFrontendContext(mFrontendContext);
     }
-    UnregisterTask(this);
   }
 
   bool Init(const JS::OwningCompileOptions& aOptions) {
-    if (!RegisterTask(this)) {
-      return false;
-    }
-
     mFrontendContext = JS::NewFrontendContext();
     if (!mFrontendContext) {
       return false;
@@ -129,26 +85,8 @@ class AsyncScriptCompileTask final : public Task {
                                                 mSrcBuf, compileStorage);
   }
 
-  // Cancel the task.
-  // If the task is already running, this waits for the task to finish.
-  void Cancel() {
-    MOZ_ASSERT(NS_IsMainThread());
-
-    MutexAutoLock lock(mMutex);
-
-    mIsCancelled = true;
-
-    mStencil = nullptr;
-  }
-
  public:
   bool Run() override {
-    MutexAutoLock lock(mMutex);
-
-    if (mIsCancelled) {
-      return true;
-    }
-
     Compile();
     return true;
   }
@@ -195,19 +133,8 @@ class AsyncScriptCompileTask final : public Task {
   RefPtr<JS::Stencil> mStencil;
 
   JS::SourceText<Utf8Unit> mSrcBuf;
-
-  // This mutex is locked during running the task or cancelling task.
-  mozilla::Mutex mMutex;
-
-  bool mIsCancelled MOZ_GUARDED_BY(mMutex) = false;
 };
 
-/* static */ mozilla::Mutex AsyncScriptCompileTask::sOngoingTasksMutex(
-    "ongoing AsyncScriptCompileTasks");
-/* static */ Vector<AsyncScriptCompileTask*>
-    AsyncScriptCompileTask::sOngoingTasks;
-/* static */ bool AsyncScriptCompileTask::sIsShutdownRegistered = false;
-
 class AsyncScriptCompiler;
 
 class AsyncScriptCompilationCompleteTask : public Task {