Host extensions

remoting/host/host_extension.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_HOST_EXTENSION_H_
+#define REMOTING_HOST_HOST_EXTENSION_H_
+
+#include <string>
+
+#include "base/memory/scoped_ptr.h"
+
+namespace remoting {
+
+class ClientSession;
+class HostExtensionSession;
+
+// Extends |ChromotingHost| with new functionality, and can use extension
+// messages to communicate with the client.
+class HostExtension {
+ public:
+  virtual ~HostExtension() {}
+
+  // Returns a space-separated list of capabilities provided by this extension.
+  // Capabilities may be used to inform the client of the availability of an
+  // extension. They are merged into the capabilities the host reports to the
+  // client.
+  virtual std::string GetCapabilities() = 0;
+
+  // Creates an extension session, which can handle extension messages for a
+  // client session.
+  // NULL may be returned if |client_session| cannot support this
+  // extension.
+  // |client_session| must outlive the resulting |HostExtensionSession|.
+  virtual scoped_ptr<HostExtensionSession> CreateExtensionSession(
+      ClientSession* client_session) = 0;
+};
+
+}  // namespace remoting
+
+#endif  // REMOTING_HOST_HOST_EXTENSION_H_