dbus/exported_object.cc - chromium/src - Git at Google

 // Copyright (c) 2012 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.

 #include "dbus/exported_object.h"

 #include <stdint.h>
 #include <utility>

 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted.h"
 #include "base/message_loop/message_loop.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time/time.h"
 #include "dbus/bus.h"
 #include "dbus/message.h"
 #include "dbus/object_path.h"
 #include "dbus/scoped_dbus_error.h"
 #include "dbus/util.h"

 namespace dbus {

 namespace {

 // Used for success ratio histograms. 1 for success, 0 for failure.
 const int kSuccessRatioHistogramMaxValue = 2;

 }  // namespace

 ExportedObject::ExportedObject(Bus* bus,
                                const ObjectPath& object_path)
     : bus_(bus),
       object_path_(object_path),
       object_is_registered_(false) {
 }

 ExportedObject::~ExportedObject() {
   DCHECK(!object_is_registered_);
 }

 bool ExportedObject::ExportMethodAndBlock(
     const std::string& interface_name,
     const std::string& method_name,
     MethodCallCallback method_call_callback) {
   bus_->AssertOnDBusThread();

   // Check if the method is already exported.
   const std::string absolute_method_name =
       GetAbsoluteMemberName(interface_name, method_name);
   if (method_table_.find(absolute_method_name) != method_table_.end()) {
     LOG(ERROR) << absolute_method_name << " is already exported";
     return false;
   }

   if (!bus_->Connect())
     return false;
   if (!bus_->SetUpAsyncOperations())
     return false;
   if (!Register())
     return false;

   // Add the method callback to the method table.
   method_table_[absolute_method_name] = method_call_callback;

   return true;
 }

 void ExportedObject::ExportMethod(const std::string& interface_name,
                                   const std::string& method_name,
                                   MethodCallCallback method_call_callback,
                                   OnExportedCallback on_exported_calback) {
   bus_->AssertOnOriginThread();

   base::Closure task = base::Bind(&ExportedObject::ExportMethodInternal,
                                   this,
                                   interface_name,
                                   method_name,
                                   method_call_callback,
                                   on_exported_calback);
   bus_->GetDBusTaskRunner()->PostTask(FROM_HERE, task);
 }

 void ExportedObject::SendSignal(Signal* signal) {
   // For signals, the object path should be set to the path to the sender
   // object, which is this exported object here.
   CHECK(signal->SetPath(object_path_));

   // Increment the reference count so we can safely reference the
   // underlying signal message until the signal sending is complete. This
   // will be unref'ed in SendSignalInternal().
   DBusMessage* signal_message = signal->raw_message();
   dbus_message_ref(signal_message);

   const base::TimeTicks start_time = base::TimeTicks::Now();
   if (bus_->GetDBusTaskRunner()->RunsTasksInCurrentSequence()) {
     // The Chrome OS power manager doesn't use a dedicated TaskRunner for
     // sending DBus messages.  Sending signals asynchronously can cause an
     // inversion in the message order if the power manager calls
     // ObjectProxy::CallMethodAndBlock() before going back to the top level of
     // the MessageLoop: crbug.com/472361.
     SendSignalInternal(start_time, signal_message);
   } else {
     bus_->GetDBusTaskRunner()->PostTask(
         FROM_HERE,
         base::Bind(&ExportedObject::SendSignalInternal,
                    this,
                    start_time,
                    signal_message));
   }
 }

 void ExportedObject::Unregister() {
   bus_->AssertOnDBusThread();

   if (!object_is_registered_)
     return;

   bus_->UnregisterObjectPath(object_path_);
   object_is_registered_ = false;
 }

 void ExportedObject::ExportMethodInternal(
     const std::string& interface_name,
     const std::string& method_name,
     MethodCallCallback method_call_callback,
     OnExportedCallback on_exported_calback) {
   bus_->AssertOnDBusThread();

   const bool success = ExportMethodAndBlock(interface_name,
                                             method_name,
                                             method_call_callback);
   bus_->GetOriginTaskRunner()->PostTask(FROM_HERE,
                                         base::Bind(&ExportedObject::OnExported,
                                                    this,
                                                    on_exported_calback,
                                                    interface_name,
                                                    method_name,
                                                    success));
 }

 void ExportedObject::OnExported(OnExportedCallback on_exported_callback,
                                 const std::string& interface_name,
                                 const std::string& method_name,
                                 bool success) {
   bus_->AssertOnOriginThread();

   on_exported_callback.Run(interface_name, method_name, success);
 }

 void ExportedObject::SendSignalInternal(base::TimeTicks start_time,
                                         DBusMessage* signal_message) {
   uint32_t serial = 0;
   bus_->Send(signal_message, &serial);
   dbus_message_unref(signal_message);
   // Record time spent to send the the signal. This is not accurate as the
   // signal will actually be sent from the next run of the message loop,
   // but we can at least tell the number of signals sent.
   UMA_HISTOGRAM_TIMES("DBus.SignalSendTime",
                       base::TimeTicks::Now() - start_time);
 }

 bool ExportedObject::Register() {
   bus_->AssertOnDBusThread();

   if (object_is_registered_)
     return true;

   ScopedDBusError error;

   DBusObjectPathVTable vtable = {};
   vtable.message_function = &ExportedObject::HandleMessageThunk;
   vtable.unregister_function = &ExportedObject::OnUnregisteredThunk;
   const bool success = bus_->TryRegisterObjectPath(object_path_,
                                                    &vtable,
                                                    this,
                                                    error.get());
   if (!success) {
     LOG(ERROR) << "Failed to register the object: " << object_path_.value()
                << ": " << (error.is_set() ? error.message() : "");
     return false;
   }

   object_is_registered_ = true;
   return true;
 }

 DBusHandlerResult ExportedObject::HandleMessage(
     DBusConnection* connection,
     DBusMessage* raw_message) {
   bus_->AssertOnDBusThread();
   DCHECK_EQ(DBUS_MESSAGE_TYPE_METHOD_CALL, dbus_message_get_type(raw_message));

   // raw_message will be unrefed on exit of the function. Increment the
   // reference so we can use it in MethodCall.
   dbus_message_ref(raw_message);
   std::unique_ptr<MethodCall> method_call(
       MethodCall::FromRawMessage(raw_message));
   const std::string interface = method_call->GetInterface();
   const std::string member = method_call->GetMember();

   if (interface.empty()) {
     // We don't support method calls without interface.
     LOG(WARNING) << "Interface is missing: " << method_call->ToString();
     return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
   }

   // Check if we know about the method.
   const std::string absolute_method_name = GetAbsoluteMemberName(
       interface, member);
   MethodTable::const_iterator iter = method_table_.find(absolute_method_name);
   if (iter == method_table_.end()) {
     // Don't know about the method.
     LOG(WARNING) << "Unknown method: " << method_call->ToString();
     return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
   }

   const base::TimeTicks start_time = base::TimeTicks::Now();
   if (bus_->HasDBusThread()) {
     // Post a task to run the method in the origin thread.
     bus_->GetOriginTaskRunner()->PostTask(FROM_HERE,
                                           base::Bind(&ExportedObject::RunMethod,
                                                      this,
                                                      iter->second,
                                                      base::Passed(&method_call),
                                                      start_time));
   } else {
     // If the D-Bus thread is not used, just call the method directly.
     MethodCall* method = method_call.get();
     iter->second.Run(method,
                      base::Bind(&ExportedObject::SendResponse,
                                 this,
                                 start_time,
                                 base::Passed(&method_call)));
   }

   // It's valid to say HANDLED here, and send a method response at a later
   // time from OnMethodCompleted() asynchronously.
   return DBUS_HANDLER_RESULT_HANDLED;
 }

 void ExportedObject::RunMethod(MethodCallCallback method_call_callback,
                                std::unique_ptr<MethodCall> method_call,
                                base::TimeTicks start_time) {
   bus_->AssertOnOriginThread();
   MethodCall* method = method_call.get();
   method_call_callback.Run(method,
                            base::Bind(&ExportedObject::SendResponse,
                                       this,
                                       start_time,
                                       base::Passed(&method_call)));
 }

 void ExportedObject::SendResponse(base::TimeTicks start_time,
                                   std::unique_ptr<MethodCall> method_call,
                                   std::unique_ptr<Response> response) {
   DCHECK(method_call);
   if (bus_->HasDBusThread()) {
     bus_->GetDBusTaskRunner()->PostTask(
         FROM_HERE,
         base::Bind(&ExportedObject::OnMethodCompleted,
                    this,
                    base::Passed(&method_call),
                    base::Passed(&response),
                    start_time));
   } else {
     OnMethodCompleted(std::move(method_call), std::move(response), start_time);
   }
 }

 void ExportedObject::OnMethodCompleted(std::unique_ptr<MethodCall> method_call,
                                        std::unique_ptr<Response> response,
                                        base::TimeTicks start_time) {
   bus_->AssertOnDBusThread();

   // Record if the method call is successful, or not. 1 if successful.
   UMA_HISTOGRAM_ENUMERATION("DBus.ExportedMethodHandleSuccess",
                             response ? 1 : 0,
                             kSuccessRatioHistogramMaxValue);

   // Check if the bus is still connected. If the method takes long to
   // complete, the bus may be shut down meanwhile.
   if (!bus_->is_connected())
     return;

   if (!response) {
     // Something bad happened in the method call.
     std::unique_ptr<ErrorResponse> error_response(ErrorResponse::FromMethodCall(
         method_call.get(), DBUS_ERROR_FAILED,
         "error occurred in " + method_call->GetMember()));
     bus_->Send(error_response->raw_message(), NULL);
     return;
   }

   // The method call was successful.
   bus_->Send(response->raw_message(), NULL);

   // Record time spent to handle the the method call. Don't include failures.
   UMA_HISTOGRAM_TIMES("DBus.ExportedMethodHandleTime",
                       base::TimeTicks::Now() - start_time);
 }

 void ExportedObject::OnUnregistered(DBusConnection* connection) {
 }

 DBusHandlerResult ExportedObject::HandleMessageThunk(
     DBusConnection* connection,
     DBusMessage* raw_message,
     void* user_data) {
   ExportedObject* self = reinterpret_cast<ExportedObject*>(user_data);
   return self->HandleMessage(connection, raw_message);
 }

 void ExportedObject::OnUnregisteredThunk(DBusConnection *connection,
                                          void* user_data) {
   ExportedObject* self = reinterpret_cast<ExportedObject*>(user_data);
   return self->OnUnregistered(connection);
 }

 }  // namespace dbus
	// Copyright (c) 2012 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.

	#include "dbus/exported_object.h"

	#include <stdint.h>
	#include <utility>

	#include "base/bind.h"
	#include "base/logging.h"
	#include "base/memory/ref_counted.h"
	#include "base/message_loop/message_loop.h"
	#include "base/metrics/histogram_macros.h"
	#include "base/threading/thread_restrictions.h"
	#include "base/time/time.h"
	#include "dbus/bus.h"
	#include "dbus/message.h"
	#include "dbus/object_path.h"
	#include "dbus/scoped_dbus_error.h"
	#include "dbus/util.h"

	namespace dbus {

	namespace {

	// Used for success ratio histograms. 1 for success, 0 for failure.
	const int kSuccessRatioHistogramMaxValue = 2;

	} // namespace

	ExportedObject::ExportedObject(Bus* bus,
	const ObjectPath& object_path)
	: bus_(bus),
	object_path_(object_path),
	object_is_registered_(false) {
	}

	ExportedObject::~ExportedObject() {
	DCHECK(!object_is_registered_);
	}

	bool ExportedObject::ExportMethodAndBlock(
	const std::string& interface_name,
	const std::string& method_name,
	MethodCallCallback method_call_callback) {
	bus_->AssertOnDBusThread();

	// Check if the method is already exported.
	const std::string absolute_method_name =
	GetAbsoluteMemberName(interface_name, method_name);
	if (method_table_.find(absolute_method_name) != method_table_.end()) {
	LOG(ERROR) << absolute_method_name << " is already exported";
	return false;
	}

	if (!bus_->Connect())
	return false;
	if (!bus_->SetUpAsyncOperations())
	return false;
	if (!Register())
	return false;

	// Add the method callback to the method table.
	method_table_[absolute_method_name] = method_call_callback;

	return true;
	}

	void ExportedObject::ExportMethod(const std::string& interface_name,
	const std::string& method_name,
	MethodCallCallback method_call_callback,
	OnExportedCallback on_exported_calback) {
	bus_->AssertOnOriginThread();

	base::Closure task = base::Bind(&ExportedObject::ExportMethodInternal,
	this,
	interface_name,
	method_name,
	method_call_callback,
	on_exported_calback);
	bus_->GetDBusTaskRunner()->PostTask(FROM_HERE, task);
	}

	void ExportedObject::SendSignal(Signal* signal) {
	// For signals, the object path should be set to the path to the sender
	// object, which is this exported object here.
	CHECK(signal->SetPath(object_path_));

	// Increment the reference count so we can safely reference the
	// underlying signal message until the signal sending is complete. This
	// will be unref'ed in SendSignalInternal().
	DBusMessage* signal_message = signal->raw_message();
	dbus_message_ref(signal_message);

	const base::TimeTicks start_time = base::TimeTicks::Now();
	if (bus_->GetDBusTaskRunner()->RunsTasksInCurrentSequence()) {
	// The Chrome OS power manager doesn't use a dedicated TaskRunner for
	// sending DBus messages. Sending signals asynchronously can cause an
	// inversion in the message order if the power manager calls
	// ObjectProxy::CallMethodAndBlock() before going back to the top level of
	// the MessageLoop: crbug.com/472361.
	SendSignalInternal(start_time, signal_message);
	} else {
	bus_->GetDBusTaskRunner()->PostTask(
	FROM_HERE,
	base::Bind(&ExportedObject::SendSignalInternal,
	this,
	start_time,
	signal_message));
	}
	}

	void ExportedObject::Unregister() {
	bus_->AssertOnDBusThread();

	if (!object_is_registered_)
	return;

	bus_->UnregisterObjectPath(object_path_);
	object_is_registered_ = false;
	}

	void ExportedObject::ExportMethodInternal(
	const std::string& interface_name,
	const std::string& method_name,
	MethodCallCallback method_call_callback,
	OnExportedCallback on_exported_calback) {
	bus_->AssertOnDBusThread();

	const bool success = ExportMethodAndBlock(interface_name,
	method_name,
	method_call_callback);
	bus_->GetOriginTaskRunner()->PostTask(FROM_HERE,
	base::Bind(&ExportedObject::OnExported,
	this,
	on_exported_calback,
	interface_name,
	method_name,
	success));
	}

	void ExportedObject::OnExported(OnExportedCallback on_exported_callback,
	const std::string& interface_name,
	const std::string& method_name,
	bool success) {
	bus_->AssertOnOriginThread();

	on_exported_callback.Run(interface_name, method_name, success);
	}

	void ExportedObject::SendSignalInternal(base::TimeTicks start_time,
	DBusMessage* signal_message) {
	uint32_t serial = 0;
	bus_->Send(signal_message, &serial);
	dbus_message_unref(signal_message);
	// Record time spent to send the the signal. This is not accurate as the
	// signal will actually be sent from the next run of the message loop,
	// but we can at least tell the number of signals sent.
	UMA_HISTOGRAM_TIMES("DBus.SignalSendTime",
	base::TimeTicks::Now() - start_time);
	}

	bool ExportedObject::Register() {
	bus_->AssertOnDBusThread();

	if (object_is_registered_)
	return true;

	ScopedDBusError error;

	DBusObjectPathVTable vtable = {};
	vtable.message_function = &ExportedObject::HandleMessageThunk;
	vtable.unregister_function = &ExportedObject::OnUnregisteredThunk;
	const bool success = bus_->TryRegisterObjectPath(object_path_,
	&vtable,
	this,
	error.get());
	if (!success) {
	LOG(ERROR) << "Failed to register the object: " << object_path_.value()
	<< ": " << (error.is_set() ? error.message() : "");
	return false;
	}

	object_is_registered_ = true;
	return true;
	}

	DBusHandlerResult ExportedObject::HandleMessage(
	DBusConnection* connection,
	DBusMessage* raw_message) {
	bus_->AssertOnDBusThread();
	DCHECK_EQ(DBUS_MESSAGE_TYPE_METHOD_CALL, dbus_message_get_type(raw_message));

	// raw_message will be unrefed on exit of the function. Increment the
	// reference so we can use it in MethodCall.
	dbus_message_ref(raw_message);
	std::unique_ptr<MethodCall> method_call(
	MethodCall::FromRawMessage(raw_message));
	const std::string interface = method_call->GetInterface();
	const std::string member = method_call->GetMember();

	if (interface.empty()) {
	// We don't support method calls without interface.
	LOG(WARNING) << "Interface is missing: " << method_call->ToString();
	return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
	}

	// Check if we know about the method.
	const std::string absolute_method_name = GetAbsoluteMemberName(
	interface, member);
	MethodTable::const_iterator iter = method_table_.find(absolute_method_name);
	if (iter == method_table_.end()) {
	// Don't know about the method.
	LOG(WARNING) << "Unknown method: " << method_call->ToString();
	return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
	}

	const base::TimeTicks start_time = base::TimeTicks::Now();
	if (bus_->HasDBusThread()) {
	// Post a task to run the method in the origin thread.
	bus_->GetOriginTaskRunner()->PostTask(FROM_HERE,
	base::Bind(&ExportedObject::RunMethod,
	this,
	iter->second,
	base::Passed(&method_call),
	start_time));
	} else {
	// If the D-Bus thread is not used, just call the method directly.
	MethodCall* method = method_call.get();
	iter->second.Run(method,
	base::Bind(&ExportedObject::SendResponse,
	this,
	start_time,
	base::Passed(&method_call)));
	}

	// It's valid to say HANDLED here, and send a method response at a later
	// time from OnMethodCompleted() asynchronously.
	return DBUS_HANDLER_RESULT_HANDLED;
	}

	void ExportedObject::RunMethod(MethodCallCallback method_call_callback,
	std::unique_ptr<MethodCall> method_call,
	base::TimeTicks start_time) {
	bus_->AssertOnOriginThread();
	MethodCall* method = method_call.get();
	method_call_callback.Run(method,
	base::Bind(&ExportedObject::SendResponse,
	this,
	start_time,
	base::Passed(&method_call)));
	}

	void ExportedObject::SendResponse(base::TimeTicks start_time,
	std::unique_ptr<MethodCall> method_call,
	std::unique_ptr<Response> response) {
	DCHECK(method_call);
	if (bus_->HasDBusThread()) {
	bus_->GetDBusTaskRunner()->PostTask(
	FROM_HERE,
	base::Bind(&ExportedObject::OnMethodCompleted,
	this,
	base::Passed(&method_call),
	base::Passed(&response),
	start_time));
	} else {
	OnMethodCompleted(std::move(method_call), std::move(response), start_time);
	}
	}

	void ExportedObject::OnMethodCompleted(std::unique_ptr<MethodCall> method_call,
	std::unique_ptr<Response> response,
	base::TimeTicks start_time) {
	bus_->AssertOnDBusThread();

	// Record if the method call is successful, or not. 1 if successful.
	UMA_HISTOGRAM_ENUMERATION("DBus.ExportedMethodHandleSuccess",
	response ? 1 : 0,
	kSuccessRatioHistogramMaxValue);

	// Check if the bus is still connected. If the method takes long to
	// complete, the bus may be shut down meanwhile.
	if (!bus_->is_connected())
	return;

	if (!response) {
	// Something bad happened in the method call.
	std::unique_ptr<ErrorResponse> error_response(ErrorResponse::FromMethodCall(
	method_call.get(), DBUS_ERROR_FAILED,
	"error occurred in " + method_call->GetMember()));
	bus_->Send(error_response->raw_message(), NULL);
	return;
	}

	// The method call was successful.
	bus_->Send(response->raw_message(), NULL);

	// Record time spent to handle the the method call. Don't include failures.
	UMA_HISTOGRAM_TIMES("DBus.ExportedMethodHandleTime",
	base::TimeTicks::Now() - start_time);
	}

	void ExportedObject::OnUnregistered(DBusConnection* connection) {
	}

	DBusHandlerResult ExportedObject::HandleMessageThunk(
	DBusConnection* connection,
	DBusMessage* raw_message,
	void* user_data) {
	ExportedObject* self = reinterpret_cast<ExportedObject*>(user_data);
	return self->HandleMessage(connection, raw_message);
	}

	void ExportedObject::OnUnregisteredThunk(DBusConnection *connection,
	void* user_data) {
	ExportedObject* self = reinterpret_cast<ExportedObject*>(user_data);
	return self->OnUnregistered(connection);
	}

	} // namespace dbus