Refactor CastSocket code for the following:

chrome/browser/extensions/api/cast_channel/cast_socket.h

 // Copyright 2013 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 CHROME_BROWSER_EXTENSIONS_API_CAST_CHANNEL_CAST_SOCKET_H_
 #define CHROME_BROWSER_EXTENSIONS_API_CAST_CHANNEL_CAST_SOCKET_H_
 
 #include <queue>
 #include <string>
 
@@ skipping 97 matching lines @@
 
  protected:
   // Creates an instance of TCPClientSocket.
   virtual scoped_ptr<net::TCPClientSocket> CreateTcpSocket();
   // Creates an instance of SSLClientSocket.
   virtual scoped_ptr<net::SSLClientSocket> CreateSslSocket();
   // Extracts peer certificate from SSLClientSocket instance when the socket
   // is in cert error state.
   // Returns whether certificate is successfully extracted.
   virtual bool ExtractPeerCert(std::string* cert);
-  // Sends a challenge request to the receiver.
-  virtual int SendAuthChallenge();
-  // Reads auth challenge reply from the receiver.
-  virtual int ReadAuthChallengeReply();
   // Verifies whether the challenge reply received from the peer is valid:
   // 1. Signature in the reply is valid.
   // 2. Certificate is rooted to a trusted CA.
   virtual bool VerifyChallengeReply();
 
   // Returns whether we are executing in a valid thread.
   virtual bool CalledOnValidThread() const;
 
  private:
   friend class ApiResourceManager<CastSocket>;
   friend class CastSocketTest;
 
   static const char* service_name() {
     return "CastSocketManager";
   }
 
   // Internal connection states.
   enum ConnectionState {
     CONN_STATE_NONE,
     CONN_STATE_TCP_CONNECT,
     CONN_STATE_TCP_CONNECT_COMPLETE,
     CONN_STATE_SSL_CONNECT,
     CONN_STATE_SSL_CONNECT_COMPLETE,
     CONN_STATE_AUTH_CHALLENGE_SEND,
     CONN_STATE_AUTH_CHALLENGE_SEND_COMPLETE,
     CONN_STATE_AUTH_CHALLENGE_REPLY_COMPLETE,
   };
 
+  // Internal write states.
+  enum WriteState {
+    WRITE_STATE_NONE,
+    WRITE_STATE_WRITE,
+    WRITE_STATE_WRITE_COMPLETE,
+    WRITE_STATE_ERROR,
+  };
+
+  // Internal read states.
+  enum ReadState {
+    READ_STATE_NONE,
+    READ_STATE_READ,
+    READ_STATE_READ_COMPLETE,
+    READ_STATE_ERROR,
+  };
+
   /////////////////////////////////////////////////////////////////////////////
   // Following methods work together to implement the following flow:
   // 1. Create a new TCP socket and connect to it
   // 2. Create a new SSL socket and try connecting to it
   // 3. If connection fails due to invalid cert authority, then extract the
   //    peer certificate from the error.
   // 4. Whitelist the peer certificate and try #1 and #2 again.
   // 5. If SSL socket is connected successfully, and if protocol is casts://
   //    then issue an auth challenge request.
   // 6. Validate the auth challenge response.
-
+  //
   // Main method that performs connection state transitions.
-  int DoConnectLoop(int result);
+  void DoConnectLoop(int result);
   // Each of the below Do* method is executed in the corresponding
   // connection state. For e.g. when connection state is TCP_CONNECT
   // DoTcpConnect is called, and so on.
   int DoTcpConnect();
   int DoTcpConnectComplete(int result);
   int DoSslConnect();
   int DoSslConnectComplete(int result);
   int DoAuthChallengeSend();
   int DoAuthChallengeSendComplete(int result);
   int DoAuthChallengeReplyComplete(int result);
   /////////////////////////////////////////////////////////////////////////////
 
-  // Callback method for callbacks from underlying sockets.
-  void OnConnectComplete(int result);
-
-  // Callback method when a challenge request is sent or a reply is received.
-  void OnChallengeEvent(int result);
-
+  // Internal implementation of the Connect method.
+  void ConnectInternal();

[Wez, 2013/11/26 02:45:56]

So is this not part of DoConnectLoop, then?

[Munjal (Google), 2013/11/26 20:06:14]

No. But now I removed it anyway.

   // Runs the external connection callback and resets it.
   void DoConnectCallback(int result);
-
   // Verifies that the URL is a valid cast:// or casts:// URL and sets url_ to
   // the result.
   bool ParseChannelUrl(const GURL& url);

[Wez, 2013/11/26 02:45:56]

nit: Why is this mixed-in in between the Connect and write impl methods?

[Munjal (Google), 2013/11/26 20:06:14]

This is a helper used by connection methods.

[Wez, 2013/11/27 04:15:19]

OK; I think it would help to clarify that, e.g. "Called by <connect method> to
verify |url| and, if valid, assign it to |url_|. Returns true if |url| is a
valid cast[s]:// URL."

 
-  // Sends the given |message| and invokes the given callback when done.
-  int SendMessageInternal(const CastMessage& message,
-                          const net::CompletionCallback& callback);
+  /////////////////////////////////////////////////////////////////////////////
+  // Following methods work together to implement write flow.
+  //
+  // Main method that performs write flow state transitions.
+  void DoWriteLoop(int result);
+  // Each of the below Do* method is executed in the corresponding
+  // write state. For e.g. when write state is WRITE_STATE_WRITE_COMPLETE
+  // DowriteComplete is called, and so on.
+  int DoWrite();
+  int DoWriteComplete(int result);
+  int DoWriteError(int result);
+  /////////////////////////////////////////////////////////////////////////////
 
-  // Writes data to the socket from the WriteRequest at the head of the queue.
-  // Calls OnWriteData() on completion.
-  int WriteData();
-  void OnWriteData(int result);
+  // Posts a task to send the given message.

[Wez, 2013/11/26 02:45:56]

Why are these methods mixed-in between the write & read impls?

[Munjal (Google), 2013/11/26 20:06:14]

These are all helper methods using during write flow.

[Wez, 2013/11/27 04:15:19]

OK; as above, I think it'd help to have a block comment introducing them as
such. (But that's a nit ;)

+  void PostTaskToSendCastMessage(const CastMessage& message,
+                                 const net::CompletionCallback& callback);
+  // Adds |message| to the write queue and starts the write loop if needed.
+  void SendCastMessageInternal(const CastMessage& message,
+                               const net::CompletionCallback& callback);
+  // Removes all messages from the write queue.
+  void ClearWriteQueue();
 
-  // Reads data from the socket into one of the read buffers. Calls
-  // OnReadData() on completion.
-  int ReadData();
-  void OnReadData(int result);
+  /////////////////////////////////////////////////////////////////////////////
+  // Following methods work together to implement read flow.
+  //
+  // Main method that performs write flow state transitions.
+  void DoReadLoop(int result);
+  // Each of the below Do* method is executed in the corresponding
+  // write state. For e.g. when write state is READ_STATE_READ_COMPLETE
+  // DoReadComplete is called, and so on.
+  int DoRead();
+  int DoReadComplete(int result);
+  int DoReadError(int result);
+  /////////////////////////////////////////////////////////////////////////////
 
+  // Posts a task to start the read loop.
+  void PostTaskToStartReadLoop();
+  // Stars the read loop if not already started.
+  void StartReadLoop();
   // Processes the contents of header_read_buffer_ and returns true on success.
   bool ProcessHeader();
   // Processes the contents of body_read_buffer_ and returns true on success.
   bool ProcessBody();
   // Parses the message held in body_read_buffer_ and notifies |delegate_| if a
   // message was extracted from the buffer.  Returns true on success.
   bool ParseMessageFromBody();
 
   // Serializes the content of message_proto (with a header) to |message_data|.
   static bool Serialize(const CastMessage& message_proto,
                         std::string* message_data);
 
   // Closes the socket and sets |error_state_|. Also signals |error| via
   // |delegate_|.
   void CloseWithError(ChannelError error);
 
   base::ThreadChecker thread_checker_;
 
   // The id of the channel.
   int channel_id_;
 
   // The URL of the peer (cast:// or casts://).
   GURL url_;
   // Delegate to inform of incoming messages and errors.
   Delegate* delegate_;
   // True if we should perform receiver authentication.
   bool auth_required_;
   // The IP endpoint of the peer.
   net::IPEndPoint ip_endpoint_;
-  // The last error encountered by the channel.
-  ChannelError error_state_;
-  // The current status of the channel.
-  ReadyState ready_state_;
-
-  // True when there is a write callback pending.
-  bool write_callback_pending_;
-  // True when there is a read callback pending.
-  bool read_callback_pending_;
 
   // IOBuffer for reading the message header.
   scoped_refptr<net::GrowableIOBuffer> header_read_buffer_;
   // IOBuffer for reading the message body.
   scoped_refptr<net::GrowableIOBuffer> body_read_buffer_;
   // IOBuffer we are currently reading into.
   scoped_refptr<net::GrowableIOBuffer> current_read_buffer_;
   // The number of bytes in the current message body.
   uint32 current_message_size_;
 
   // The NetLog for this service.
   net::NetLog* net_log_;
   // The NetLog source for this service.
   net::NetLog::Source net_log_source_;
 
-  // Next connection state to transition to.
-  ConnectionState next_state_;
   // Owned ptr to the underlying TCP socket.
   scoped_ptr<net::TCPClientSocket> tcp_socket_;
   // Owned ptr to the underlying SSL socket.
   scoped_ptr<net::SSLClientSocket> socket_;
   // Certificate of the peer. This field may be empty if the peer
   // certificate is not yet fetched.
   std::string peer_cert_;
   scoped_ptr<net::CertVerifier> cert_verifier_;
   scoped_ptr<net::TransportSecurityState> transport_security_state_;
   // Reply received from the receiver to a challenge request.
   scoped_ptr<CastMessage> challenge_reply_;
 
   // Callback invoked when the socket is connected.
   net::CompletionCallback connect_callback_;
 
+  // Connection flow state machine state.
+  ConnectionState connect_state_;
+  // Write flow state machine state.
+  WriteState write_state_;
+  // Read flow state machine state.
+  ReadState read_state_;
+  // The last error encountered by the channel.
+  ChannelError error_state_;
+  // The current status of the channel.
+  ReadyState ready_state_;
+
   // Message header struct. If fields are added, be sure to update
   // kMessageHeaderSize in the .cc.
   struct MessageHeader {
     MessageHeader();
     // Sets the message size.
     void SetMessageSize(size_t message_size);
     // Prepends this header to |str|.
     void PrependToString(std::string* str);
     // Reads |header| from the beginning of |buffer|.
     static void ReadFromIOBuffer(net::GrowableIOBuffer* buffer,
@@ skipping 12 matching lines @@
     // and prepending the header.  Must only be called once.
     bool SetContent(const CastMessage& message_proto);
 
     net::CompletionCallback callback;
     scoped_refptr<net::DrainableIOBuffer> io_buffer;
   };
   // Queue of pending writes. The message at the front of the queue is the one
   // being written.
   std::queue<WriteRequest> write_queue_;
 
-  // Used to protect against DoConnectLoop() re-entrancy.
-  bool in_connect_loop_;
-
   FRIEND_TEST_ALL_PREFIXES(CastSocketTest, TestCastURLs);
   FRIEND_TEST_ALL_PREFIXES(CastSocketTest, TestRead);
   FRIEND_TEST_ALL_PREFIXES(CastSocketTest, TestReadMany);
   DISALLOW_COPY_AND_ASSIGN(CastSocket);
 };
 
 }  // namespace cast_channel
 }  // namespace api
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_CAST_CHANNEL_CAST_SOCKET_H_