dbus/exported_object.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef DBUS_EXPORTED_OBJECT_H_
   6 #define DBUS_EXPORTED_OBJECT_H_
   7
   8 #include <dbus/dbus.h>
   9
  10 #include <map>
  11 #include <string>
  12 #include <utility>
  13
  14 #include "base/callback.h"
  15 #include "base/memory/ref_counted.h"
  16 #include "base/synchronization/waitable_event.h"
  17 #include "base/threading/platform_thread.h"
  18 #include "base/time.h"
  19 #include "dbus/dbus_export.h"
  20 #include "dbus/object_path.h"
  21
  22 namespace dbus {
  23
  24 class Bus;
  25 class MethodCall;
  26 class Response;
  27 class Signal;
  28
  29 // ExportedObject is used to export objects and methods to other D-Bus
  30 // clients.
  31 //
  32 // ExportedObject is a ref counted object, to ensure that |this| of the
  33 // object is alive when callbacks referencing |this| are called.
  34 class CHROME_DBUS_EXPORT ExportedObject
  35     : public base::RefCountedThreadSafe<ExportedObject> {
  36  public:
  37   // Client code should use Bus::GetExportedObject() instead of this
  38   // constructor.
  39   ExportedObject(Bus* bus, const ObjectPath& object_path);
  40
  41   // Called to send a response from an exported method. |response| is the
  42   // response message. Callers should pass NULL in the event of an error that
  43   // prevents the sending of a response.
  44   typedef base::Callback<void (scoped_ptr<Response> response)> ResponseSender;
  45
  46   // Called when an exported method is called. |method_call| is the request
  47   // message. |sender| is the callback that's used to send a response.
  48   //
  49   // |method_call| is owned by ExportedObject, hence client code should not
  50   // delete |method_call|.
  51   typedef base::Callback<void (MethodCall* method_call, ResponseSender sender)>
  52       MethodCallCallback;
  53
  54   // Called when method exporting is done.
  55   // |success| indicates whether exporting was successful or not.
  56   typedef base::Callback<void (const std::string& interface_name,
  57                                const std::string& method_name,
  58                                bool success)>
  59       OnExportedCallback;
  60
  61   // Exports the method specified by |interface_name| and |method_name|,
  62   // and blocks until exporting is done. Returns true on success.
  63   //
  64   // |method_call_callback| will be called in the origin thread, when the
  65   // exported method is called. As it's called in the origin thread,
  66   // |method_callback| can safely reference objects in the origin thread
  67   // (i.e. UI thread in most cases).
  68   //
  69   // BLOCKING CALL.
  70   virtual bool ExportMethodAndBlock(const std::string& interface_name,
  71                                     const std::string& method_name,
  72                                     MethodCallCallback method_call_callback);
  73
  74   // Requests to export the method specified by |interface_name| and
  75   // |method_name|. See Also ExportMethodAndBlock().
  76   //
  77   // |on_exported_callback| is called when the method is exported or
  78   // failed to be exported, in the origin thread.
  79   //
  80   // Must be called in the origin thread.
  81   virtual void ExportMethod(const std::string& interface_name,
  82                             const std::string& method_name,
  83                             MethodCallCallback method_call_callback,
  84                             OnExportedCallback on_exported_callback);
  85
  86   // Requests to send the signal from this object. The signal will be sent
  87   // asynchronously from the message loop in the D-Bus thread.
  88   virtual void SendSignal(Signal* signal);
  89
  90   // Unregisters the object from the bus. The Bus object will take care of
  91   // unregistering so you don't have to do this manually.
  92   //
  93   // BLOCKING CALL.
  94   virtual void Unregister();
  95
  96  protected:
  97   // This is protected, so we can define sub classes.
  98   virtual ~ExportedObject();
  99
 100  private:
 101   friend class base::RefCountedThreadSafe<ExportedObject>;
 102
 103   // Helper function for ExportMethod().
 104   void ExportMethodInternal(const std::string& interface_name,
 105                             const std::string& method_name,
 106                             MethodCallCallback method_call_callback,
 107                             OnExportedCallback exported_callback);
 108
 109   // Called when the object is exported.
 110   void OnExported(OnExportedCallback on_exported_callback,
 111                   const std::string& interface_name,
 112                   const std::string& method_name,
 113                   bool success);
 114
 115   // Helper function for SendSignal().
 116   void SendSignalInternal(base::TimeTicks start_time,
 117                           DBusMessage* signal_message);
 118
 119   // Registers this object to the bus.
 120   // Returns true on success, or the object is already registered.
 121   //
 122   // BLOCKING CALL.
 123   bool Register();
 124
 125   // Handles the incoming request messages and dispatches to the exported
 126   // methods.
 127   DBusHandlerResult HandleMessage(DBusConnection* connection,
 128                                   DBusMessage* raw_message);
 129
 130   // Runs the method. Helper function for HandleMessage().
 131   void RunMethod(MethodCallCallback method_call_callback,
 132                  scoped_ptr<MethodCall> method_call,
 133                  base::TimeTicks start_time);
 134
 135   // Callback invoked by service provider to send a response to a method call.
 136   // Can be called immediately from a MethodCallCallback to implement a
 137   // synchronous service or called later to implement an asynchronous service.
 138   void SendResponse(base::TimeTicks start_time,
 139                     scoped_ptr<MethodCall> method_call,
 140                     scoped_ptr<Response> response);
 141
 142   // Called on completion of the method run from SendResponse().
 143   // Takes ownership of |method_call| and |response|.
 144   void OnMethodCompleted(scoped_ptr<MethodCall> method_call,
 145                          scoped_ptr<Response> response,
 146                          base::TimeTicks start_time);
 147
 148   // Called when the object is unregistered.
 149   void OnUnregistered(DBusConnection* connection);
 150
 151   // Redirects the function call to HandleMessage().
 152   static DBusHandlerResult HandleMessageThunk(DBusConnection* connection,
 153                                               DBusMessage* raw_message,
 154                                               void* user_data);
 155
 156   // Redirects the function call to OnUnregistered().
 157   static void OnUnregisteredThunk(DBusConnection* connection,
 158                                   void* user_data);
 159
 160   scoped_refptr<Bus> bus_;
 161   ObjectPath object_path_;
 162   bool object_is_registered_;
 163
 164   // The method table where keys are absolute method names (i.e. interface
 165   // name + method name), and values are the corresponding callbacks.
 166   typedef std::map<std::string, MethodCallCallback> MethodTable;
 167   MethodTable method_table_;
 168 };
 169
 170 }  // namespace dbus
 171
 172 #endif  // DBUS_EXPORTED_OBJECT_H_