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// Copyright (c) 2013 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 <stdint.h>
#include <map>
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "dbus/object_path.h"
#include "dbus/property.h"
// Newer D-Bus services implement the Object Manager interface to inform other
// clients about the objects they export, the properties of those objects, and
// notification of changes in the set of available objects:
// #standard-interfaces-objectmanager
// This interface is very closely tied to the Properties interface, and uses
// even more levels of nested dictionaries and variants. In addition to
// simplifying implementation, since there tends to be a single object manager
// per service, spanning the complete set of objects an interfaces available,
// the classes implemented here make dealing with this interface simpler.
// Except where noted, use of this class replaces the need for the code
// documented in dbus/property.h
// Client implementation classes should begin by deriving from the
// dbus::ObjectManager::Interface class, and defining a Properties structure as
// documented in dbus/property.h.
// Example:
// class ExampleClient : public dbus::ObjectManager::Interface {
// public:
// struct Properties : public dbus::PropertySet {
// dbus::Property<std::string> name;
// dbus::Property<uint16_t> version;
// dbus::Property<dbus::ObjectPath> parent;
// dbus::Property<std::vector<std::string>> children;
// Properties(dbus::ObjectProxy* object_proxy,
// const PropertyChangedCallback callback)
// : dbus::PropertySet(object_proxy, kExampleInterface, callback) {
// RegisterProperty("Name", &name);
// RegisterProperty("Version", &version);
// RegisterProperty("Parent", &parent);
// RegisterProperty("Children", &children);
// }
// virtual ~Properties() {}
// };
// The link between the implementation class and the object manager is set up
// in the constructor and removed in the destructor; the class should maintain
// a pointer to its object manager for use in other methods and establish
// itself as the implementation class for its interface.
// Example:
// explicit ExampleClient::ExampleClient(dbus::Bus* bus)
// : bus_(bus),
// weak_ptr_factory_(this) {
// object_manager_ = bus_->GetObjectManager(kServiceName, kManagerPath);
// object_manager_->RegisterInterface(kInterface, this);
// }
// virtual ExampleClient::~ExampleClient() {
// object_manager_->UnregisterInterface(kInterface);
// }
// This class calls GetManagedObjects() asynchronously after the remote service
// becomes available and additionally refreshes managed objects after the
// service stops or restarts.
// The object manager interface class has one abstract method that must be
// implemented by the class to create Properties structures on demand. As well
// as implementing this, you will want to implement a public GetProperties()
// method.
// Example:
// dbus::PropertySet* CreateProperties(dbus::ObjectProxy* object_proxy,
// const std::string& interface_name)
// override {
// Properties* properties = new Properties(
// object_proxy, interface_name,
// base::Bind(&PropertyChanged,
// weak_ptr_factory_.GetWeakPtr(),
// object_path));
// return static_cast<dbus::PropertySet*>(properties);
// }
// Properties* GetProperties(const dbus::ObjectPath& object_path) {
// return static_cast<Properties*>(
// object_manager_->GetProperties(object_path, kInterface));
// }
// Note that unlike classes that only use dbus/property.h there is no need
// to connect signals or obtain the initial values of properties. The object
// manager class handles that for you.
// PropertyChanged is a method of your own to notify your observers of a change
// in your properties, either as a result of a signal from the Properties
// interface or from the Object Manager interface. You may also wish to
// implement the optional ObjectAdded and ObjectRemoved methods of the class
// to likewise notify observers.
// When your class needs an object proxy for a given object path, it may
// obtain it from the object manager. Unlike the equivalent method on the bus
// this will return NULL if the object is not known.
// object_proxy = object_manager_->GetObjectProxy(object_path);
// if (object_proxy) {
// ...
// }
// There is no need for code using your implementation class to be aware of the
// use of object manager behind the scenes, the rules for updating properties
// documented in dbus/property.h still apply.
namespace dbus {
const char kObjectManagerInterface[] = "org.freedesktop.DBus.ObjectManager";
const char kObjectManagerGetManagedObjects[] = "GetManagedObjects";
const char kObjectManagerInterfacesAdded[] = "InterfacesAdded";
const char kObjectManagerInterfacesRemoved[] = "InterfacesRemoved";
class Bus;
class MessageReader;
class ObjectProxy;
class Response;
class Signal;
// ObjectManager implements both the D-Bus client components of the D-Bus
// Object Manager interface, as internal methods, and a public API for
// client classes to utilize.
class CHROME_DBUS_EXPORT ObjectManager final
: public base::RefCountedThreadSafe<ObjectManager> {
// ObjectManager::Interface must be implemented by any class wishing to have
// its remote objects managed by an ObjectManager.
class Interface {
virtual ~Interface() {}
// Called by ObjectManager to create a Properties structure for the remote
// D-Bus object identified by |object_path| and accessibile through
// |object_proxy|. The D-Bus interface name |interface_name| is that passed
// to RegisterInterface() by the implementation class.
// The implementation class should create and return an instance of its own
// subclass of dbus::PropertySet; ObjectManager will then connect signals
// and update the properties from its own internal message reader.
virtual PropertySet* CreateProperties(
ObjectProxy *object_proxy,
const dbus::ObjectPath& object_path,
const std::string& interface_name) = 0;
// Called by ObjectManager to inform the implementation class that an
// object has been added with the path |object_path|. The D-Bus interface
// name |interface_name| is that passed to RegisterInterface() by the
// implementation class.
// If a new object implements multiple interfaces, this method will be
// called on each interface implementation with differing values of
// |interface_name| as appropriate. An implementation class will only
// receive multiple calls if it has registered for multiple interfaces.
virtual void ObjectAdded(const ObjectPath& object_path,
const std::string& interface_name) { }
// Called by ObjectManager to inform the implementation class than an
// object with the path |object_path| has been removed. Ths D-Bus interface
// name |interface_name| is that passed to RegisterInterface() by the
// implementation class. Multiple interfaces are handled as with
// ObjectAdded().
// This method will be called before the Properties structure and the
// ObjectProxy object for the given interface are cleaned up, it is safe
// to retrieve them during removal to vary processing.
virtual void ObjectRemoved(const ObjectPath& object_path,
const std::string& interface_name) { }
// Client code should use Bus::GetObjectManager() instead of this constructor.
static scoped_refptr<ObjectManager> Create(Bus* bus,
const std::string& service_name,
const ObjectPath& object_path);
// Register a client implementation class |interface| for the given D-Bus
// interface named in |interface_name|. That object's CreateProperties()
// method will be used to create instances of dbus::PropertySet* when
// required.
void RegisterInterface(const std::string& interface_name,
Interface* interface);
// Unregister the implementation class for the D-Bus interface named in
// |interface_name|, objects and properties of this interface will be
// ignored.
void UnregisterInterface(const std::string& interface_name);
// Returns a list of object paths, in an undefined order, of objects known
// to this manager.
std::vector<ObjectPath> GetObjects();
// Returns the list of object paths, in an undefined order, of objects
// implementing the interface named in |interface_name| known to this manager.
std::vector<ObjectPath> GetObjectsWithInterface(
const std::string& interface_name);
// Returns a ObjectProxy pointer for the given |object_path|. Unlike
// the equivalent method on Bus this will return NULL if the object
// manager has not been informed of that object's existence.
ObjectProxy* GetObjectProxy(const ObjectPath& object_path);
// Returns a PropertySet* pointer for the given |object_path| and
// |interface_name|, or NULL if the object manager has not been informed of
// that object's existence or the interface's properties. The caller should
// cast the returned pointer to the appropriate type, e.g.:
// static_cast<Properties*>(GetProperties(object_path, my_interface));
PropertySet* GetProperties(const ObjectPath& object_path,
const std::string& interface_name);
// Instructs the object manager to refresh its list of managed objects;
// automatically called by the D-Bus thread manager, there should never be
// a need to call this manually.
void GetManagedObjects();
// Cleans up any match rules and filter functions added by this ObjectManager.
// The Bus object will take care of this so you don't have to do it manually.
void CleanUp();
friend class base::RefCountedThreadSafe<ObjectManager>;
ObjectManager(Bus* bus,
const std::string& service_name,
const ObjectPath& object_path);
// Called from the constructor to add a match rule for PropertiesChanged
// signals on the D-Bus thread and set up a corresponding filter function.
bool SetupMatchRuleAndFilter();
// Called on the origin thread once the match rule and filter have been set
// up. Connects the InterfacesAdded and InterfacesRemoved signals and
// refreshes objects if the service is available. |success| is false if an
// error occurred during setup and true otherwise.
void OnSetupMatchRuleAndFilterComplete(bool success);
// Called by dbus:: when a message is received. This is used to filter
// PropertiesChanged signals from the correct sender and relay the event to
// the correct PropertySet.
static DBusHandlerResult HandleMessageThunk(DBusConnection* connection,
DBusMessage* raw_message,
void* user_data);
DBusHandlerResult HandleMessage(DBusConnection* connection,
DBusMessage* raw_message);
// Called when a PropertiesChanged signal is received from the sender.
// This method notifies the relevant PropertySet that it should update its
// properties based on the received signal. Called from HandleMessage.
void NotifyPropertiesChanged(const dbus::ObjectPath object_path,
Signal* signal);
void NotifyPropertiesChangedHelper(const dbus::ObjectPath object_path,
Signal* signal);
// Called by dbus:: in response to the GetManagedObjects() method call.
void OnGetManagedObjects(Response* response);
// Called by dbus:: when an InterfacesAdded signal is received and initially
// connected.
void InterfacesAddedReceived(Signal* signal);
void InterfacesAddedConnected(const std::string& interface_name,
const std::string& signal_name,
bool success);
// Called by dbus:: when an InterfacesRemoved signal is received and
// initially connected.
void InterfacesRemovedReceived(Signal* signal);
void InterfacesRemovedConnected(const std::string& interface_name,
const std::string& signal_name,
bool success);
// Updates the map entry for the object with path |object_path| using the
// D-Bus message in |reader|, which should consist of an dictionary mapping
// interface names to properties dictionaries as recieved by both the
// GetManagedObjects() method return and the InterfacesAdded() signal.
void UpdateObject(const ObjectPath& object_path, MessageReader* reader);
// Updates the properties structure of the object with path |object_path|
// for the interface named |interface_name| using the D-Bus message in
// |reader| which should consist of the properties dictionary for that
// interface.
// Called by UpdateObjects() for each interface in the dictionary; this
// method takes care of both creating the entry in the ObjectMap and
// ObjectProxy if required, as well as the PropertySet instance for that
// interface if necessary.
void AddInterface(const ObjectPath& object_path,
const std::string& interface_name,
MessageReader* reader);
// Removes the properties structure of the object with path |object_path|
// for the interfaces named |interface_name|.
// If no further interfaces remain, the entry in the ObjectMap is discarded.
void RemoveInterface(const ObjectPath& object_path,
const std::string& interface_name);
// Removes all objects and interfaces from the object manager when
// |old_owner| is not the empty string and/or re-requests the set of managed
// objects when |new_owner| is not the empty string.
void NameOwnerChanged(const std::string& old_owner,
const std::string& new_owner);
Bus* bus_;
std::string service_name_;
std::string service_name_owner_;
std::string match_rule_;
ObjectPath object_path_;
ObjectProxy* object_proxy_;
bool setup_success_;
bool cleanup_called_;
// Maps the name of an interface to the implementation class used for
// instantiating PropertySet structures for that interface's properties.
typedef std::map<std::string, Interface*> InterfaceMap;
InterfaceMap interface_map_;
// Each managed object consists of a ObjectProxy used to make calls
// against that object and a collection of D-Bus interface names and their
// associated PropertySet structures.
struct Object {
ObjectProxy* object_proxy;
// Maps the name of an interface to the specific PropertySet structure
// of that interface's properties.
typedef std::map<const std::string, PropertySet*> PropertiesMap;
PropertiesMap properties_map;
// Maps the object path of an object to the Object structure.
typedef std::map<const ObjectPath, Object*> ObjectMap;
ObjectMap object_map_;
// Weak pointer factory for generating 'this' pointers that might live longer
// than we do.
// Note: This should remain the last member so it'll be destroyed and
// invalidate its weak pointers before any other members are destroyed.
base::WeakPtrFactory<ObjectManager> weak_ptr_factory_;
} // namespace dbus