Remote Assistance on Chrome OS Part II - Native Messaging renaming

extensions/browser/api/messaging/native_messaging_channel.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 EXTENSIONS_BROWSER_API_MESSAGING_NATIVE_MESSAGING_CHANNEL_H_
+#define EXTENSIONS_BROWSER_API_MESSAGING_NATIVE_MESSAGING_CHANNEL_H_
+
+#include "base/callback.h"
+
+namespace base {
+class Value;
+}  // namespace base
+
+namespace extensions {
+
+// Defines an interface to read messages and send responses between a native

[Sergey Ulanov, 2014/09/17 02:32:22]

It's not clear which side of the channel is supposed to implement this
interface. Will it be used on both ends (then you need a connector) or is going
to be implemented by the chrome's side and passed to the host object?

[kelvinp, 2014/09/17 23:06:16]

The native_messaging_channel is simply an object that supports sending and
receiving messages.  Both chrome and native messaging side shares the same
interface.  We can distinguish the side of the communication via variable
naming.  For instance, on the Chrome side, we can name the object as
native_channel, so that we know native_channel->Send will send message to the
native component.

+// component and chrome.
+class NativeMessagingChannel {
+ public:
+  // Callback interface for the channel. |EventHandler| must be valid as long as

[Sergey Ulanov, 2014/09/17 02:32:22]

Normally |pipes| are not used for type names, only for variables.

[kelvinp, 2014/09/17 23:06:16]

Done.

+  // |NativeMessagingChannel| is valid.
+  class EventHandler {
+   public:
+    // Invoked when a message is received from the other endpoint.
+    virtual void OnMessage(scoped_ptr<base::Value> message) = 0;
+
+    // Invoked when there is an error in sending or receiving a message.
+    // The event handler should shut down the channel on this event.
+    virtual void OnDisconnect() = 0;
+
+    virtual ~EventHandler() {}
+  };
+
+  virtual ~NativeMessagingChannel() {}
+
+  // Starts reading and processing messages.
+  virtual void Start(EventHandler* event_handler) = 0;
+
+  // Sends a message to the other endpoint.
+  virtual void SendMessage(scoped_ptr<base::Value> message) = 0;
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_API_MESSAGING_NATIVE_MESSAGING_CHANNEL_H_