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
new file mode 100644
index 0000000000000000000000000000000000000000..0eba2a35cec8d2b7bcf74bff4d59fabaeba5af15
--- /dev/null
+++ b/ipc/ipc_channel_factory.h
@@ -0,0 +1,55 @@
+// 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"
+
+namespace IPC {
+
+// A ChannelFactory listens on a UNIX domain socket and passes the FDs that get
+// created when a client connects to its delegate. It is the delegate's

[palmer, 2013/03/06 00:59:21]

"FDs that get created" — by whom?

Passes the FDs to where? "to its delegate" could also apply to "when a client
connects". :)

[jeremya, 2013/03/06 05:03:18]

Updated the comment :)

+// responsibility to create an IPC::Channel from the given FD.
+class 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 CreatePipe();

[Mark Mentovai, 2013/03/05 20:08:03]

This “pipe” business is a little bit misleading. I think of “pipe” as a “named
pipe,” where you’re dealing with “UNIX-domain sockets” which are similar but
different. Is there a better name that you could use for CreatePipe(),
listen_pipe_, and some of the comments and local variables in the .cc file?

[jeremya, 2013/03/06 05:03:18]

Done. s/pipe/fd/g, s/CreatePipe/CreateSocket

+  virtual void OnFileCanReadWithoutBlocking(int fd) OVERRIDE;
+  virtual void OnFileCanWriteWithoutBlocking(int fd) OVERRIDE {}

[Mark Mentovai, 2013/03/05 20:08:03]

Inlining this (empty) function here seems like more trouble than it’s worth.

You can move it to the .cc file and you can also stick a NOTREACHED() in it.

[jeremya, 2013/03/06 05:03:18]

Done.

+
+  MessageLoopForIO::FileDescriptorWatcher server_listen_connection_watcher_;
+  base::FilePath path_;
+  Delegate* delegate_;
+  int listen_pipe_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChannelFactory);
+};
+
+}

[Mark Mentovai, 2013/03/05 20:08:03]

}  // namespace IPC

[jeremya, 2013/03/06 05:03:18]

Done.

+
+#endif  // IPC_IPC_CHANNEL_FACTORY_H_