Me2me Native Messaging host on Windows: restructure NativeMessagingHost and NativeMessagingChannel.…

remoting/host/native_messaging/native_messaging_channel.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 REMOTING_HOST_NATIVE_MESSAGING_NATIVE_MESSAGING_CHANNEL_H_
 #define REMOTING_HOST_NATIVE_MESSAGING_NATIVE_MESSAGING_CHANNEL_H_
 
 #include "base/callback.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/platform_file.h"
 #include "base/threading/non_thread_safe.h"
 #include "remoting/host/native_messaging/native_messaging_reader.h"
 #include "remoting/host/native_messaging/native_messaging_writer.h"
 
 namespace base {
 class DictionaryValue;
 class Value;
 }  // namespace base
 
 namespace remoting {
 
 // Implements reading messages and sending responses across the native messaging
-// host pipe. Delegates processing of received messages to Delegate.
-//
-// TODO(alexeypa): Add ability to switch between different |delegate_| pointers
-// on the fly. This is useful for implementing UAC-style elevation on Windows -
-// an unprivileged delegate could be replaced with another delegate that
-// forwards messages to the elevated instance of the native messaging host.
+// host pipe.
 class NativeMessagingChannel : public base::NonThreadSafe {
  public:
   // Used to send a message to the client app.
   typedef base::Callback<void(scoped_ptr<base::DictionaryValue> message)>
       SendMessageCallback;
 
-  class Delegate {
-   public:
-    virtual ~Delegate() {}
-
-    // Sets the callback the delegate can use to send a message to the client.
-    virtual void SetSendMessageCallback(
-        const SendMessageCallback& send_message) = 0;
-
-    // Processes a message received from the client app.
-    virtual void ProcessMessage(scoped_ptr<base::DictionaryValue> message) = 0;
-  };
-
   // Constructs an object taking the ownership of |input| and |output|. Closes
   // |input| and |output| to prevent the caller from using them.
-  NativeMessagingChannel(
-      scoped_ptr<Delegate> delegate,
-      base::PlatformFile input,
-      base::PlatformFile output);
+  NativeMessagingChannel(base::PlatformFile input, base::PlatformFile output);
   ~NativeMessagingChannel();
 
   // Starts reading and processing messages.
-  void Start(const base::Closure& quit_closure);
+  void Start(const SendMessageCallback& received_message,
+             const base::Closure& quit_closure);
+
+  // Sends a message to the client app.
+  void SendMessage(scoped_ptr<base::DictionaryValue> message);
 
  private:
   // Processes a message received from the client app.
   void ProcessMessage(scoped_ptr<base::Value> message);
 
-  // Sends a message to the client app.
-  void SendMessage(scoped_ptr<base::DictionaryValue> message);
-
   // Initiates shutdown and runs |quit_closure| if there are no pending requests
   // left.
   void Shutdown();
 
   base::Closure quit_closure_;
 
   NativeMessagingReader native_messaging_reader_;
   scoped_ptr<NativeMessagingWriter> native_messaging_writer_;
 
-  // |delegate_| may post tasks to this object during destruction (but not
-  // afterwards), so it needs to be destroyed before other members of this class
-  // (except for |weak_factory_|).
-  scoped_ptr<Delegate> delegate_;
+  // The callback to invoke when a message is received.
+  SendMessageCallback received_message_;
 
   base::WeakPtr<NativeMessagingChannel> weak_ptr_;
   base::WeakPtrFactory<NativeMessagingChannel> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeMessagingChannel);
 };
 
 }  // namespace remoting
 
 #endif  // REMOTING_HOST_NATIVE_MESSAGING_NATIVE_MESSAGING_CHANNEL_H_