Implement IPC::ChannelFactory, a class that accept()s on a UNIX socket.

ipc/ipc_channel_factory.h

Index: ipc/ipc_channel_factory.h
diff --git a/ipc/ipc_channel_factory.h b/ipc/ipc_channel_factory.h
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+++ b/ipc/ipc_channel_factory.h
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+// 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 IPC_IPC_CHANNEL_FACTORY_H_
+#define IPC_IPC_CHANNEL_FACTORY_H_
+
+#include "base/files/file_path.h"
+#include "base/message_loop.h"
+#include "ipc/ipc_channel_handle.h"
+#include "ipc/ipc_export.h"
+
+namespace IPC {
+
+// A ChannelFactory listens on a UNIX domain socket. When a client connects to
+// the socket, it accept()s the connection and passes the new FD to the
+// delegate. The delegate is then responsible for creating a new IPC::Channel
+// for the FD.
+class IPC_EXPORT ChannelFactory : public MessageLoopForIO::Watcher {
+ public:
+  class Delegate {
+   public:
+    // Called when a client connects to the factory. It is the delegate's
+    // responsibility to create an IPC::Channel for the handle, or else close
+    // the file descriptor contained therein.
+    virtual void OnClientConnected(const ChannelHandle& handle) = 0;
+
+    // Called when an error occurs and the channel is closed.
+    virtual void OnListenError() = 0;
+  };
+
+  ChannelFactory(const base::FilePath& path, Delegate* delegate);
+
+  virtual ~ChannelFactory();
+
+  // Call this to start listening on the socket.
+  bool Listen();
+
+  // Close and unlink the socket, and stop accepting connections.
+  void Close();
+
+ private:
+  bool CreateSocket();
+  virtual void OnFileCanReadWithoutBlocking(int fd) OVERRIDE;
+  virtual void OnFileCanWriteWithoutBlocking(int fd) OVERRIDE;
+
+  MessageLoopForIO::FileDescriptorWatcher server_listen_connection_watcher_;
+  base::FilePath path_;
+  Delegate* delegate_;
+  int listen_fd_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChannelFactory);
+};
+
+}  // namespace IPC
+
+#endif  // IPC_IPC_CHANNEL_FACTORY_H_