Implement Bus and ObjectProxy classes for our D-Bus library.

dbus/object_proxy.h

+// Copyright (c) 2011 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.
+//
+// D-Bus library for Chrome.
+
+#ifndef DBUS_OBJECT_PROXY_H_
+#define DBUS_OBJECT_PROXY_H_
+#pragma once
+
+#include <string>
+#include <vector>
+#include <dbus/dbus.h>
+
+#include "base/callback.h"
+#include "base/memory/ref_counted.h"
+#include "base/threading/platform_thread.h"
+
+class MessageLoop;
+
+namespace dbus {
+
+class Bus;
+class MethodCall;
+class Response;
+
+// ObjectProxy is used to communicate with remote objects, such as calling
+// methods and sending signals.
+//
+// TODO(satorux): Add support for sending signals.
+class ObjectProxy  {
+ public:
+  virtual ~ObjectProxy();
+
+  // The constants correspond to DBUS_TIMEOUT_USE_DEFAULT and
+  // DBUS_TIMEOUT_INFINITE. Here we use literal numbers instead of these
+  // macros as these aren't defined with D-Bus earlier than 1.4.12.
+  // http://dbus.freedesktop.org/doc/api/html/group__DBusPendingCall.html
+  enum {
+    // Note: the default timeout is set to 25 secs per
+    // dbus-1.2.16/dbus/dbus-connection-internal.h
+    // #define _DBUS_DEFAULT_TIMEOUT_VALUE (25 * 1000)
+    TIMEOUT_USE_DEFAULT = -1,
+    TIMEOUT_INFINITE = 0x7fffffff,
+  };
+
+  // Used for CallMethodAsync().
+  typedef base::Callback<void(Response*)> ResponseCallback;
+
+  // Calls the method of the remote object and waits until the response is
+  // returned. This is a blocking call hence shouldn't be called from the
+  // UI thread.
+  virtual bool CallMethodAndWait(MethodCall* method_call,
+                                 Response* response,
+                                 int timeout_ms);
+
+  // Calls the method of the remote object. |callback| will be called in
+  // the message loop of the thread that calls this function. If the
+  // method call is successful, a valid Response object will be passed to
+  // the callback, and the callback needs to delete the response object.
+  // If the method call is unsuccessful, NULL will be passed to the
+  // callback.
+  //
+  // This is not a blocking call (this function just posts a task to the
+  // message loop in another thread maintained by Bus object), hence it's
+  // safe to be called from the UI thread.
+  //
+  // TODO(satorux): Implement timeout. timeout_ms is currently unused.
+  virtual void CallMethod(MethodCall* method_call,
+                          ResponseCallback callback,
+                          int timeout_ms);
+
+  const std::string& service_name() const { return service_name_; }
+  const std::string& object_path() const { return object_path_; }
+
+ private:
+  // Struct of data we'll be passing from StartAsyncMethodCall() to
+  // OnPendingCallIsCompleteStub().
+  struct OnPendingCallIsCompleteData {
+    OnPendingCallIsCompleteData(ObjectProxy* in_object_proxy,
+                                MessageLoop* in_origin_loop,
+                                ResponseCallback in_response_callback);
+    ObjectProxy* object_proxy;
+    MessageLoop* origin_loop;
+    ResponseCallback response_callback;
+  };
+
+  // Starts the async method call.
+  void StartAsyncMethodCall(int timeout_ms,
+                            void* request_message,
+                            MessageLoop* origin_loop,
+                            ResponseCallback response_callback);
+
+  // Called when the pending call is complete.
+  void OnPendingCallIsComplete(DBusPendingCall* pending_call,
+                               ResponseCallback response_callback,
+                               MessageLoop* origin_loop);
+
+  // Runs the response callback with the given response object.
+  void RunResponseCallback(ResponseCallback response_callback,
+                           Response* response);
+
+  // Checks whether the current thread is on the same thread that created
+  // the object proxy. If not, DCHECK() will fail.
+  void AssertOnOriginThread();
+
+  // Checks whether the current thread is on the IO thread, if the
+  // underlying bus is configured to use it. If not, DCHECK() will fail.
+  //
+  // The function does the same with AssertOnOriginThread() if the bus is
+  // NOT configured to use the IO thread.
+  void AssertOnIoThreadIfConfigured();
+
+  // Redirects the function call to OnPendingCallIsComplete().
+  static void OnPendingCallIsCompleteStub(DBusPendingCall* pending_call,
+                                          void* user_data);
+
+  friend class Bus;
+
+  // The object proxy can only be created by Bus.
+  ObjectProxy(Bus* bus,
+              const std::string& service_name,
+              const std::string& object_path);
+
+  Bus* bus_;
+  std::string service_name_;
+  std::string object_path_;
+  const base::PlatformThreadId origin_thread_id_;
+
+  DISALLOW_COPY_AND_ASSIGN(ObjectProxy);
+};
+
+}  // namespace dbus
+
+#endif  // DBUS_OBJECT_PROXY_H_