Making AsyncInvoker destructor thread-safe.

webrtc/base/asyncinvoker-inl.h

 /*
  *  Copyright 2014 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #ifndef WEBRTC_BASE_ASYNCINVOKER_INL_H_
 #define WEBRTC_BASE_ASYNCINVOKER_INL_H_
 
+#include "webrtc/base/atomicops.h"
 #include "webrtc/base/bind.h"
 #include "webrtc/base/callback.h"
 #include "webrtc/base/criticalsection.h"
 #include "webrtc/base/messagehandler.h"
 #include "webrtc/base/refcount.h"
 #include "webrtc/base/scoped_ref_ptr.h"
 #include "webrtc/base/sigslot.h"
 #include "webrtc/base/thread.h"
 
 namespace rtc {
 
 class AsyncInvoker;
 
 // Helper class for AsyncInvoker. Runs a task and triggers a callback
 // on the calling thread if necessary. Instances are ref-counted so their
 // lifetime can be independent of AsyncInvoker.
 class AsyncClosure : public RefCountInterface {
  public:
+  explicit AsyncClosure(AsyncInvoker* invoker) : invoker_(invoker) {}
   // Runs the asynchronous task, and triggers a callback to the calling
   // thread if needed. Should be called from the target thread.
   virtual void Execute() = 0;
  protected:
-  ~AsyncClosure() override {}
+  ~AsyncClosure() override;
+
+  AsyncInvoker* invoker_;
 };
 
 // Simple closure that doesn't trigger a callback for the calling thread.
 template <class FunctorT>
 class FireAndForgetAsyncClosure : public AsyncClosure {
  public:
-  explicit FireAndForgetAsyncClosure(const FunctorT& functor)
-      : functor_(functor) {}
+  explicit FireAndForgetAsyncClosure(AsyncInvoker* invoker,
+                                     const FunctorT& functor)
+      : AsyncClosure(invoker), functor_(functor) {}
   virtual void Execute() {
     functor_();
   }
  private:
   FunctorT functor_;
 };
 
 // Base class for closures that may trigger a callback for the calling thread.
 // Listens for the "destroyed" signals from the calling thread and the invoker,
 // and cancels the callback to the calling thread if either is destroyed.
 class NotifyingAsyncClosureBase : public AsyncClosure,
                                   public sigslot::has_slots<> {
  public:
   ~NotifyingAsyncClosureBase() override;
 
  protected:
   NotifyingAsyncClosureBase(AsyncInvoker* invoker,
                             const Location& callback_posted_from,
                             Thread* calling_thread);
   void TriggerCallback();
   void SetCallback(const Callback0<void>& callback) {
     CritScope cs(&crit_);
     callback_ = callback;
   }
   bool CallbackCanceled() const { return calling_thread_ == NULL; }
 
  private:
-  AsyncInvoker* invoker_;
   Location callback_posted_from_;
   Callback0<void> callback_;
   CriticalSection crit_;
   Thread* calling_thread_;
 
   void CancelCallback();
 };
 
 // Closures that have a non-void return value and require a callback.
 template <class ReturnT, class FunctorT, class HostT>
@@ skipping 47 matching lines @@
     TriggerCallback();
   }
 
  private:
   FunctorT functor_;
 };
 
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_ASYNCINVOKER_INL_H_