Make MessageReader class not ref-counted.

remoting/protocol/message_reader.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 REMOTING_PROTOCOL_MESSAGE_READER_H_
 #define REMOTING_PROTOCOL_MESSAGE_READER_H_
 
 #include "base/bind.h"
 #include "base/callback.h"
-#include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
-#include "base/message_loop_proxy.h"
+#include "base/memory/weak_ptr.h"
+#include "base/threading/non_thread_safe.h"
 #include "net/base/completion_callback.h"
 #include "remoting/base/compound_buffer.h"
 #include "remoting/protocol/message_decoder.h"
 
-class MessageLoop;
-
 namespace net {
 class IOBuffer;
 class Socket;
 }  // namespace net
 
 namespace remoting {
 namespace protocol {
 
 // MessageReader reads data from the socket asynchronously and calls
 // callback for each message it receives. It stops calling the
 // callback as soon as the socket is closed, so the socket should
 // always be closed before the callback handler is destroyed.
 //
 // In order to throttle the stream, MessageReader doesn't try to read
 // new data from the socket until all previously received messages are
 // processed by the receiver (|done_task| is called for each message).
 // It is still possible that the MessageReceivedCallback is called
 // twice (so that there is more than one outstanding message),
 // e.g. when we the sender sends multiple messages in one TCP packet.
-class MessageReader : public base::RefCountedThreadSafe<MessageReader> {
+class MessageReader : public base::NonThreadSafe {
  public:
   typedef base::Callback<void(scoped_ptr<CompoundBuffer>, const base::Closure&)>
       MessageReceivedCallback;
 
   MessageReader();
+  virtual ~MessageReader();
 
   // Initialize the MessageReader with a socket. If a message is received
   // |callback| is called.
   void Init(net::Socket* socket, const MessageReceivedCallback& callback);
 
  private:
-  friend class base::RefCountedThreadSafe<MessageReader>;
-  virtual ~MessageReader();
-
   void DoRead();
   void OnRead(int result);
   void HandleReadResult(int result);
   void OnDataReceived(net::IOBuffer* data, int data_size);
-  void OnMessageDone(scoped_refptr<base::SingleThreadTaskRunner> task_runner);
-  void ProcessDoneEvent();
+  void OnMessageDone();
 
   net::Socket* socket_;
 
   // Set to true, when we have a socket read pending, and expecting
   // OnRead() to be called when new data is received.
   bool read_pending_;
 
   // Number of messages that we received, but haven't finished
   // processing yet, i.e. |done_task| hasn't been called for these
   // messages.
   int pending_messages_;
 
   bool closed_;
   scoped_refptr<net::IOBuffer> read_buffer_;
 
   MessageDecoder message_decoder_;
 
   // Callback is called when a message is received.
   MessageReceivedCallback message_received_callback_;
+
+  base::WeakPtrFactory<MessageReader> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(MessageReader);
 };
 
 // Version of MessageReader for protocol buffer messages, that parses
 // each incoming message.
 template <class T>
 class ProtobufMessageReader {
  public:
-  typedef typename base::Callback<void(scoped_ptr<T>, const base::Closure&)>
+  // The callback that is called when a new message is received. |done_task|
+  // must be called by the callback when it's done processing the |message|.
+  typedef typename base::Callback<void(scoped_ptr<T> message,
+                                       const base::Closure& done_task)>
       MessageReceivedCallback;
 
   ProtobufMessageReader() { };
   ~ProtobufMessageReader() { };
 
   void Init(net::Socket* socket, const MessageReceivedCallback& callback) {
     DCHECK(!callback.is_null());
     message_received_callback_ = callback;
-    message_reader_ = new MessageReader();
+    message_reader_.reset(new MessageReader());
     message_reader_->Init(
         socket, base::Bind(&ProtobufMessageReader<T>::OnNewData,
                            base::Unretained(this)));
   }
 
  private:
   void OnNewData(scoped_ptr<CompoundBuffer> buffer,
                  const base::Closure& done_task) {
     scoped_ptr<T> message(new T());
     CompoundBufferInputStream stream(buffer.get());
     bool ret = message->ParseFromZeroCopyStream(&stream);
     if (!ret) {
       LOG(WARNING) << "Received message that is not a valid protocol buffer.";
     } else {
       DCHECK_EQ(stream.position(), buffer->total_bytes());
       message_received_callback_.Run(message.Pass(), done_task);
     }
   }
 
-  scoped_refptr<MessageReader> message_reader_;
+  scoped_ptr<MessageReader> message_reader_;
   MessageReceivedCallback message_received_callback_;
 };
 
 }  // namespace protocol
 }  // namespace remoting
 
 #endif  // REMOTING_PROTOCOL_MESSAGE_READER_H_