dbus/exported_object.cc

   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 #include "dbus/exported_object.h"
   6
   7 #include "base/bind.h"
   8 #include "base/logging.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/message_loop.h"
  11 #include "base/metrics/histogram.h"
  12 #include "base/threading/thread_restrictions.h"
  13 #include "base/time.h"
  14 #include "dbus/bus.h"
  15 #include "dbus/message.h"
  16 #include "dbus/object_path.h"
  17 #include "dbus/scoped_dbus_error.h"
  18
  19 namespace dbus {
  20
  21 namespace {
  22
  23 // Used for success ratio histograms. 1 for success, 0 for failure.
  24 const int kSuccessRatioHistogramMaxValue = 2;
  25
  26 // Gets the absolute method name by concatenating the interface name and
  27 // the method name. Used for building keys for method_table_ in
  28 // ExportedObject.
  29 std::string GetAbsoluteMethodName(
  30     const std::string& interface_name,
  31     const std::string& method_name) {
  32   return interface_name + "." + method_name;
  33 }
  34
  35 }  // namespace
  36
  37 ExportedObject::ExportedObject(Bus* bus,
  38                                const ObjectPath& object_path)
  39     : bus_(bus),
  40       object_path_(object_path),
  41       object_is_registered_(false) {
  42 }
  43
  44 ExportedObject::~ExportedObject() {
  45   DCHECK(!object_is_registered_);
  46 }
  47
  48 bool ExportedObject::ExportMethodAndBlock(
  49     const std::string& interface_name,
  50     const std::string& method_name,
  51     MethodCallCallback method_call_callback) {
  52   bus_->AssertOnDBusThread();
  53
  54   // Check if the method is already exported.
  55   const std::string absolute_method_name =
  56       GetAbsoluteMethodName(interface_name, method_name);
  57   if (method_table_.find(absolute_method_name) != method_table_.end()) {
  58     LOG(ERROR) << absolute_method_name << " is already exported";
  59     return false;
  60   }
  61
  62   if (!bus_->Connect())
  63     return false;
  64   if (!bus_->SetUpAsyncOperations())
  65     return false;
  66   if (!Register())
  67     return false;
  68
  69   // Add the method callback to the method table.
  70   method_table_[absolute_method_name] = method_call_callback;
  71
  72   return true;
  73 }
  74
  75 void ExportedObject::ExportMethod(const std::string& interface_name,
  76                                   const std::string& method_name,
  77                                   MethodCallCallback method_call_callback,
  78                                   OnExportedCallback on_exported_calback) {
  79   bus_->AssertOnOriginThread();
  80
  81   base::Closure task = base::Bind(&ExportedObject::ExportMethodInternal,
  82                                   this,
  83                                   interface_name,
  84                                   method_name,
  85                                   method_call_callback,
  86                                   on_exported_calback);
  87   bus_->PostTaskToDBusThread(FROM_HERE, task);
  88 }
  89
  90 void ExportedObject::SendSignal(Signal* signal) {
  91   // For signals, the object path should be set to the path to the sender
  92   // object, which is this exported object here.
  93   CHECK(signal->SetPath(object_path_));
  94
  95   // Increment the reference count so we can safely reference the
  96   // underlying signal message until the signal sending is complete. This
  97   // will be unref'ed in SendSignalInternal().
  98   DBusMessage* signal_message = signal->raw_message();
  99   dbus_message_ref(signal_message);
 100
 101   const base::TimeTicks start_time = base::TimeTicks::Now();
 102   bus_->PostTaskToDBusThread(FROM_HERE,
 103                              base::Bind(&ExportedObject::SendSignalInternal,
 104                                         this,
 105                                         start_time,
 106                                         signal_message));
 107 }
 108
 109 void ExportedObject::Unregister() {
 110   bus_->AssertOnDBusThread();
 111
 112   if (!object_is_registered_)
 113     return;
 114
 115   bus_->UnregisterObjectPath(object_path_);
 116   object_is_registered_ = false;
 117 }
 118
 119 void ExportedObject::ExportMethodInternal(
 120     const std::string& interface_name,
 121     const std::string& method_name,
 122     MethodCallCallback method_call_callback,
 123     OnExportedCallback on_exported_calback) {
 124   bus_->AssertOnDBusThread();
 125
 126   const bool success = ExportMethodAndBlock(interface_name,
 127                                             method_name,
 128                                             method_call_callback);
 129   bus_->PostTaskToOriginThread(FROM_HERE,
 130                                base::Bind(&ExportedObject::OnExported,
 131                                           this,
 132                                           on_exported_calback,
 133                                           interface_name,
 134                                           method_name,
 135                                           success));
 136 }
 137
 138 void ExportedObject::OnExported(OnExportedCallback on_exported_callback,
 139                                 const std::string& interface_name,
 140                                 const std::string& method_name,
 141                                 bool success) {
 142   bus_->AssertOnOriginThread();
 143
 144   on_exported_callback.Run(interface_name, method_name, success);
 145 }
 146
 147 void ExportedObject::SendSignalInternal(base::TimeTicks start_time,
 148                                         DBusMessage* signal_message) {
 149   uint32 serial = 0;
 150   bus_->Send(signal_message, &serial);
 151   dbus_message_unref(signal_message);
 152   // Record time spent to send the the signal. This is not accurate as the
 153   // signal will actually be sent from the next run of the message loop,
 154   // but we can at least tell the number of signals sent.
 155   UMA_HISTOGRAM_TIMES("DBus.SignalSendTime",
 156                       base::TimeTicks::Now() - start_time);
 157 }
 158
 159 bool ExportedObject::Register() {
 160   bus_->AssertOnDBusThread();
 161
 162   if (object_is_registered_)
 163     return true;
 164
 165   ScopedDBusError error;
 166
 167   DBusObjectPathVTable vtable = {};
 168   vtable.message_function = &ExportedObject::HandleMessageThunk;
 169   vtable.unregister_function = &ExportedObject::OnUnregisteredThunk;
 170   const bool success = bus_->TryRegisterObjectPath(object_path_,
 171                                                    &vtable,
 172                                                    this,
 173                                                    error.get());
 174   if (!success) {
 175     LOG(ERROR) << "Failed to register the object: " << object_path_.value()
 176                << ": " << (error.is_set() ? error.message() : "");
 177     return false;
 178   }
 179
 180   object_is_registered_ = true;
 181   return true;
 182 }
 183
 184 DBusHandlerResult ExportedObject::HandleMessage(
 185     DBusConnection* connection,
 186     DBusMessage* raw_message) {
 187   bus_->AssertOnDBusThread();
 188   DCHECK_EQ(DBUS_MESSAGE_TYPE_METHOD_CALL, dbus_message_get_type(raw_message));
 189
 190   // raw_message will be unrefed on exit of the function. Increment the
 191   // reference so we can use it in MethodCall.
 192   dbus_message_ref(raw_message);
 193   scoped_ptr<MethodCall> method_call(
 194       MethodCall::FromRawMessage(raw_message));
 195   const std::string interface = method_call->GetInterface();
 196   const std::string member = method_call->GetMember();
 197
 198   if (interface.empty()) {
 199     // We don't support method calls without interface.
 200     LOG(WARNING) << "Interface is missing: " << method_call->ToString();
 201     return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 202   }
 203
 204   // Check if we know about the method.
 205   const std::string absolute_method_name = GetAbsoluteMethodName(
 206       interface, member);
 207   MethodTable::const_iterator iter = method_table_.find(absolute_method_name);
 208   if (iter == method_table_.end()) {
 209     // Don't know about the method.
 210     LOG(WARNING) << "Unknown method: " << method_call->ToString();
 211     return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
 212   }
 213
 214   const base::TimeTicks start_time = base::TimeTicks::Now();
 215   if (bus_->HasDBusThread()) {
 216     // Post a task to run the method in the origin thread.
 217     bus_->PostTaskToOriginThread(FROM_HERE,
 218                                  base::Bind(&ExportedObject::RunMethod,
 219                                             this,
 220                                             iter->second,
 221                                             method_call.release(),
 222                                             start_time));
 223   } else {
 224     // If the D-Bus thread is not used, just call the method directly.
 225     MethodCall* released_method_call = method_call.release();
 226     iter->second.Run(released_method_call,
 227                      base::Bind(&ExportedObject::SendResponse,
 228                                 this,
 229                                 start_time,
 230                                 released_method_call));
 231   }
 232
 233   // It's valid to say HANDLED here, and send a method response at a later
 234   // time from OnMethodCompleted() asynchronously.
 235   return DBUS_HANDLER_RESULT_HANDLED;
 236 }
 237
 238 void ExportedObject::RunMethod(MethodCallCallback method_call_callback,
 239                                MethodCall* method_call,
 240                                base::TimeTicks start_time) {
 241   bus_->AssertOnOriginThread();
 242   method_call_callback.Run(method_call,
 243                            base::Bind(&ExportedObject::SendResponse,
 244                                       this,
 245                                       start_time,
 246                                       method_call));
 247 }
 248
 249 void ExportedObject::SendResponse(base::TimeTicks start_time,
 250                                   MethodCall* method_call,
 251                                   Response* response) {
 252   DCHECK(method_call);
 253   if (bus_->HasDBusThread()) {
 254     bus_->PostTaskToDBusThread(FROM_HERE,
 255                                base::Bind(&ExportedObject::OnMethodCompleted,
 256                                           this,
 257                                           method_call,
 258                                           response,
 259                                           start_time));
 260   } else {
 261     OnMethodCompleted(method_call, response, start_time);
 262   }
 263 }
 264
 265 void ExportedObject::OnMethodCompleted(MethodCall* method_call,
 266                                        Response* response,
 267                                        base::TimeTicks start_time) {
 268   bus_->AssertOnDBusThread();
 269   scoped_ptr<MethodCall> method_call_deleter(method_call);
 270   scoped_ptr<Response> response_deleter(response);
 271
 272   // Record if the method call is successful, or not. 1 if successful.
 273   UMA_HISTOGRAM_ENUMERATION("DBus.ExportedMethodHandleSuccess",
 274                             response ? 1 : 0,
 275                             kSuccessRatioHistogramMaxValue);
 276
 277   // Check if the bus is still connected. If the method takes long to
 278   // complete, the bus may be shut down meanwhile.
 279   if (!bus_->is_connected())
 280     return;
 281
 282   if (!response) {
 283     // Something bad happened in the method call.
 284     scoped_ptr<dbus::ErrorResponse> error_response(
 285         ErrorResponse::FromMethodCall(
 286             method_call,
 287             DBUS_ERROR_FAILED,
 288             "error occurred in " + method_call->GetMember()));
 289     bus_->Send(error_response->raw_message(), NULL);
 290     return;
 291   }
 292
 293   // The method call was successful.
 294   bus_->Send(response->raw_message(), NULL);
 295
 296   // Record time spent to handle the the method call. Don't include failures.
 297   UMA_HISTOGRAM_TIMES("DBus.ExportedMethodHandleTime",
 298                       base::TimeTicks::Now() - start_time);
 299 }
 300
 301 void ExportedObject::OnUnregistered(DBusConnection* connection) {
 302 }
 303
 304 DBusHandlerResult ExportedObject::HandleMessageThunk(
 305     DBusConnection* connection,
 306     DBusMessage* raw_message,
 307     void* user_data) {
 308   ExportedObject* self = reinterpret_cast<ExportedObject*>(user_data);
 309   return self->HandleMessage(connection, raw_message);
 310 }
 311
 312 void ExportedObject::OnUnregisteredThunk(DBusConnection *connection,
 313                                          void* user_data) {
 314   ExportedObject* self = reinterpret_cast<ExportedObject*>(user_data);
 315   return self->OnUnregistered(connection);
 316 }
 317
 318 }  // namespace dbus