Add abstract interfaces for the transport layer.

remoting/protocol/transport.h

+// Copyright (c) 2012 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.
+//
+// This file defines the interface for peer-to-peer transport. There
+// are two types of transport: StreamTransport and DatagramTransport.
+// They must both be created using TransportFactory instances and they
+// provide the same interface, except that one should be used for
+// reliable stream connection and the other one for unreliable
+// datagram connection. The Transport interface itself doesn't provide
+// methods to send/receive data. Instead it creates an instance of
+// net::Socket or net::SocketStream which provides access to the data
+// channel. After a new transport is Initialize()'ed the Connect()
+// method must be called. Connect() starts asynchronous creation and
+// initialization of the connection socket that can be used later to
+// send and receive data. The socket is passed to the callback
+// specified in the Connect() call. The Transport object must exist
+// during the whole lifetime of the connection socket. Later deletion
+// of the connection socket causes teardown of the corresponding
+// Transport object.
+
+#ifndef REMOTING_PROTOCOL_TRANSPORT_H_
+#define REMOTING_PROTOCOL_TRANSPORT_H_
+
+#include <string>
+
+#include "base/basictypes.h"
+#include "base/callback_forward.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/threading/non_thread_safe.h"
+
+namespace cricket {
+class Candidate;
+}  // namespace cricket
+
+namespace net {
+class Socket;
+class StreamSocket;
+}  // namespace net
+
+namespace remoting {
+namespace protocol {
+
+class ChannelAuthenticator;
+struct TransportConfig;
+
+class Transport : public base::NonThreadSafe {
+ public:
+  class EventHandler {
+   public:
+    EventHandler() {};
+    virtual ~EventHandler() {};
+
+    // Called when the transport generates a new candidate that needs
+    // to be passed to the AddRemoteCandidate() method on the remote
+    // end of the connection.
+    virtual void OnTransportCandidate(Transport* transport,
+                                      const cricket::Candidate& candidate) = 0;
+
+    // Called when the transport is about to be deleted.
+    virtual void OnTransportDeleted(Transport* transport) = 0;
+  };
+
+  Transport() {}
+  virtual ~Transport() {}
+
+  // Intialize the transport with the specified parameters.
+  // |authenticator| is used to secure and authenticate the connection.
+  virtual void Initialize(const std::string& name,
+                          const TransportConfig& config,
+                          Transport::EventHandler* event_handler,
+                          scoped_ptr<ChannelAuthenticator> authenticator) = 0;
+
+  // Adds |candidate| received from the peer.
+  virtual void AddRemoteCandidate(const cricket::Candidate& candidate) = 0;
+
+  // Name of the channel. It is used to identify the channel and
+  // disambiguate candidates it generates from candidates generated by
+  // parallel connections.
+  virtual const std::string& name() const = 0;
+
+  // Returns true if the channel is already connected.
+  virtual bool is_connected() const = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(Transport);
+};
+
+class StreamTransport : public Transport {
+ public:
+  typedef base::Callback<void(scoped_ptr<net::StreamSocket>)> ConnectedCallback;
+
+  StreamTransport() { }
+  virtual ~StreamTransport() { }
+
+  virtual void Connect(const ConnectedCallback& callback) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(StreamTransport);
+};
+
+class DatagramTransport : public Transport {
+ public:
+  typedef base::Callback<void(scoped_ptr<net::Socket>)> ConnectedCallback;
+
+  DatagramTransport() { }
+  virtual ~DatagramTransport() { }
+
+  virtual void Connect(const ConnectedCallback& callback) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(DatagramTransport);
+};
+
+class TransportFactory {
+ public:
+  TransportFactory() { }
+  virtual ~TransportFactory() { }
+
+  virtual scoped_ptr<StreamTransport> CreateStreamTransport() = 0;
+  virtual scoped_ptr<DatagramTransport> CreateDatagramTransport() = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TransportFactory);
+};
+
+}  // namespace protocol
+}  // namespace remoting
+
+#endif  // REMOTING_PROTOCOL_TRANSPORT_H_