Accept inbound connections on unix domain socket

mojo/shell/external_application_listener.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 MOJO_SHELL_EXTERNAL_APPLICATION_LISTENER_H_
+#define MOJO_SHELL_EXTERNAL_APPLICATION_LISTENER_H_
+
+#include "base/callback.h"
+#include "base/files/file_path.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/sequenced_task_runner.h"
+#include "mojo/public/cpp/system/message_pipe.h"
+#include "net/socket/socket_descriptor.h"
+#include "url/gurl.h"
+
+namespace mojo {
+namespace shell {
+
+// In order to support Mojo apps whose lifetime is managed by
+// something other than mojo_shell, mojo_shell needs to support a
+// mechanism by which such an application can discover a running shell
+// instance, connect to it, and ask to be "registered" at a given
+// URL. Registration implies that the app can be connected to at that
+// URL from then on out, and that the app has received a usable ShellPtr.
+//
+// External applications can connect to the shell using the
+// ExternalApplicationRegistrarConnection class.
+class ExternalApplicationListener {
+ public:
+  // When run, a RegisterCallback should note that an app has asked to be
+  // registered at app_url and Bind the provided pipe handle to a ShellImpl.
+  typedef base::Callback<void(const GURL& app_url,
+                              ScopedMessagePipeHandle shell)> RegisterCallback;
+  typedef base::Callback<void(int rv)> ErrorCallback;
+
+  virtual ~ExternalApplicationListener() {}
+
+  // Implementations of this class may use two threads, an IO thread for
+  // listening and accepting incoming sockets, and a "main" thread
+  // where all Mojo traffic is processed and provided callbacks are run.
+  static scoped_ptr<ExternalApplicationListener> Create(
+      const scoped_refptr<base::SequencedTaskRunner>& shell_runner,
+      const scoped_refptr<base::SequencedTaskRunner>& io_runner);
+
+  static base::FilePath ConstructDefaultSocketPath();
+
+  // Begin listening (on io_runner) to a socket at listen_socket_path.
+  // Incoming registration requests will be forwarded to register_callback.
+  // Errors are ignored.
+  virtual void ListenInBackground(
+      const base::FilePath& listen_socket_path,
+      const RegisterCallback& register_callback) = 0;
+
+  // Begin listening (on io_runner) to a socket at listen_socket_path.
+  // Incoming registration requests will be forwarded to register_callback.
+  // Errors are reported via error_callback.
+  virtual void ListenInBackgroundWithErrorCallback(
+      const base::FilePath& listen_socket_path,
+      const RegisterCallback& register_callback,
+      const ErrorCallback& error_callback) = 0;
+
+  // Block the current thread until listening has started on io_runner.
+  // If listening has already started, returns immediately.
+  virtual void WaitForListening() = 0;
+};
+
+}  // namespace shell
+}  // namespace mojo
+
+#endif  // MOJO_SHELL_EXTERNAL_APPLICATION_LISTENER_H_