Remote Assistance on Chrome OS Part III - NativeMessageHost

remoting/host/native_messaging/native_messaging_pipe.h

+// Copyright 2014 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_PIPE_H_
+#define REMOTING_HOST_NATIVE_MESSAGING_NATIVE_MESSAGING_PIPE_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "extensions/browser/api/messaging/native_message_host.h"
+#include "extensions/browser/api/messaging/native_messaging_channel.h"
+
+namespace base {
+class Value;
+}
+
+namespace remoting {
+
+// Connects a extensions::NativeMessageHost to a PipeMessagingChannel.
+class NativeMessagingPipe
+    : public extensions::NativeMessagingChannel::EventHandler,
+      public extensions::NativeMessageHost::Client,
+      public base::SupportsWeakPtr<NativeMessagingPipe> {
+ public:
+  NativeMessagingPipe();
+  virtual ~NativeMessagingPipe();
+
+  void Init(scoped_ptr<extensions::NativeMessageHost> host,
+            scoped_ptr<extensions::NativeMessagingChannel> channel);
+
+  // Starts processing messages from the pipe.
+  void Start(const base::Closure& quit_closure);

[Sergey Ulanov, 2014/09/27 00:24:10]

Do we need separate Init() and Start()? Merge them to a single method?

[kelvinp, 2014/09/29 22:59:40]

I think it is better to keep the construction of the object (init) and starting
the object (which has the side effect of start receiving messages) separate. 
This will make the code more flexible if we decided to assemble the object in
and different place than starting it in the future.

[Sergey Ulanov, 2014/09/30 20:33:39]

I still think they shouldn't be separate unless you have a usecase for that.
E.g. how do you know that you want to pass NativeMessagingChannel to Init()
instead of Start(), if at some point you actually need them to be separate? Why
|quit_closure| is passed to Start() and not Init()?
This adds code complexity for no benefits. If at point we find that we need
these methods to be separate it would be trivial to separate them.

+
+  // extensions::NativeMessageHost::Client implementation.
+  virtual void PostMessageFromNativeHost(const std::string& message) OVERRIDE;
+  virtual void CloseChannel(const std::string& error_message) OVERRIDE;
+
+  // extensions::NativeMessagingChannel::EventHandler implementation.
+  virtual void OnMessage(scoped_ptr<base::Value> message) OVERRIDE;
+  virtual void OnDisconnect() OVERRIDE;
+
+ private:
+  base::Closure quit_closure_;
+  scoped_ptr<extensions::NativeMessagingChannel> channel_;
+  scoped_ptr<extensions::NativeMessageHost> host_;
+
+  DISALLOW_COPY_AND_ASSIGN(NativeMessagingPipe);
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_NATIVE_MESSAGING_NATIVE_MESSAGING_PIPE_H_