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