Making AsyncInvoker destructor thread-safe.

webrtc/base/asyncinvoker.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_H_
 #define WEBRTC_BASE_ASYNCINVOKER_H_
 
 #include "webrtc/base/asyncinvoker-inl.h"
 #include "webrtc/base/bind.h"
 #include "webrtc/base/constructormagic.h"
+#include "webrtc/base/event.h"
 #include "webrtc/base/sigslot.h"
-#include "webrtc/base/scopedptrcollection.h"
 #include "webrtc/base/thread.h"
 
 namespace rtc {
 
 // Invokes function objects (aka functors) asynchronously on a Thread, and
 // owns the lifetime of calls (ie, when this object is destroyed, calls in
 // flight are cancelled). AsyncInvoker can optionally execute a user-specified
 // function when the asynchronous call is complete, or operates in
 // fire-and-forget mode otherwise.
 //
@@ skipping 44 matching lines @@
   ~AsyncInvoker() override;
 
   // Call |functor| asynchronously on |thread|, with no callback upon
   // completion. Returns immediately.
   template <class ReturnT, class FunctorT>
   void AsyncInvoke(const Location& posted_from,
                    Thread* thread,
                    const FunctorT& functor,
                    uint32_t id = 0) {
     scoped_refptr<AsyncClosure> closure(
-        new RefCountedObject<FireAndForgetAsyncClosure<FunctorT> >(functor));
+        new RefCountedObject<FireAndForgetAsyncClosure<FunctorT> >(this,
+                                                                   functor));
     DoInvoke(posted_from, thread, closure, id);
   }
 
   // Call |functor| asynchronously on |thread| with |delay_ms|, with no callback
   // upon completion. Returns immediately.
   template <class ReturnT, class FunctorT>
   void AsyncInvokeDelayed(const Location& posted_from,
                           Thread* thread,
                           const FunctorT& functor,
                           uint32_t delay_ms,
                           uint32_t id = 0) {
     scoped_refptr<AsyncClosure> closure(
-        new RefCountedObject<FireAndForgetAsyncClosure<FunctorT> >(functor));
+        new RefCountedObject<FireAndForgetAsyncClosure<FunctorT> >(this,
+                                                                   functor));
     DoInvokeDelayed(posted_from, thread, closure, delay_ms, id);
   }
 
   // Call |functor| asynchronously on |thread|, calling |callback| when done.
   // Uses a separate Location for |callback_posted_from| so that the functor
   // invoke and the callback invoke can be differentiated.
   template <class ReturnT, class FunctorT, class HostT>
   void AsyncInvoke(const Location& posted_from,
                    const Location& callback_posted_from,
                    Thread* thread,
@@ skipping 41 matching lines @@
   void OnMessage(Message* msg) override;
   void DoInvoke(const Location& posted_from,
                 Thread* thread,
                 const scoped_refptr<AsyncClosure>& closure,
                 uint32_t id);
   void DoInvokeDelayed(const Location& posted_from,
                        Thread* thread,
                        const scoped_refptr<AsyncClosure>& closure,
                        uint32_t delay_ms,
                        uint32_t id);
-  bool destroying_;
+  volatile int pending_invocations_ = 0;
+  Event invocation_complete_;
+  bool destroying_ = false;
+  friend class AsyncClosure;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(AsyncInvoker);
 };
 
 // Similar to AsyncInvoker, but guards against the Thread being destroyed while
 // there are outstanding dangling pointers to it. It will connect to the current
 // thread in the constructor, and will get notified when that thread is
 // destroyed. After GuardedAsyncInvoker is constructed, it can be used from
 // other threads to post functors to the thread it was constructed on. If that
 // thread dies, any further calls to AsyncInvoke() will be safely ignored.
@@ skipping 77 matching lines @@
   void ThreadDestroyed();
 
   CriticalSection crit_;
   Thread* thread_ GUARDED_BY(crit_);
   AsyncInvoker invoker_ GUARDED_BY(crit_);
 };
 
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_ASYNCINVOKER_H_