Make HostController/DeviceListener deletion fully synchronous.

tools/android/forwarder2/host_controller.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef TOOLS_ANDROID_FORWARDER2_HOST_CONTROLLER_H_
 #define TOOLS_ANDROID_FORWARDER2_HOST_CONTROLLER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
 #include "base/threading/thread.h"
+#include "tools/android/forwarder2/forwarders_manager.h"
 #include "tools/android/forwarder2/pipe_notifier.h"
 #include "tools/android/forwarder2/self_deleter_helper.h"
 #include "tools/android/forwarder2/socket.h"
 
 namespace forwarder2 {
 
 // This class partners with DeviceController and has the same lifetime and
 // threading characteristics as DeviceListener. In a nutshell, this class
 // operates on its own thread and is destroyed on the thread it was constructed
 // on. The class' deletion can happen in two different ways:
@@ skipping 33 matching lines @@
                  int exit_notifier_fd,
                  const ErrorCallback& error_callback,
                  scoped_ptr<Socket> adb_control_socket,
                  scoped_ptr<PipeNotifier> delete_controller_notifier);
 
   void ReadNextCommandSoon();
   void ReadCommandOnInternalThread();
 
   void StartForwarder(scoped_ptr<Socket> host_server_data_socket);
 
-  // Helper method that creates a socket and adds the appropriate event file
-  // descriptors.
-  scoped_ptr<Socket> CreateSocket();
-
   // Note that this gets also called when ~HostController() is invoked.
   void OnInternalThreadError();
 
   void UnmapPortOnDevice();
 
   SelfDeleterHelper<HostController> self_deleter_helper_;
   const int device_port_;
   const int host_port_;
   const int adb_port_;
   // Used to notify the controller when the process is killed.
   const int global_exit_notifier_fd_;
   scoped_ptr<Socket> adb_control_socket_;
-  scoped_ptr<PipeNotifier> delete_controller_notifier_;
   // Used to cancel the pending blocking IO operations when the host controller
   // instance is deleted.
-  // Task runner used for deletion set at construction time (i.e. the object is
+  scoped_ptr<PipeNotifier> delete_controller_notifier_;
+  // Task runner used for deletion set at deletion time (i.e. the object is
   // deleted on the same thread it is created on).
   const scoped_refptr<base::SingleThreadTaskRunner> deletion_task_runner_;
+  // Note that this thread must outlive |forwarders_manager_| below. The
+  // ForwardersManager's internal delegate (outliving ForwardersManager) may
+  // post a task to this thread when it gets deleted. Also note that
+  // base::Thread joins on destruction which means that ~Thread() will only
+  // return after it executed all the tasks enqueued in its message loop. This
+  // also means that it is guaranteed that all the Forwarder instances owned by
+  // the ForwardersManager's internal delegate are destructed before
+  // ~HostController() returns.
   base::Thread thread_;
+  ForwardersManager forwarders_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(HostController);
 };
 
 }  // namespace forwarder2
 
 #endif  // TOOLS_ANDROID_FORWARDER2_HOST_CONTROLLER_H_