TpDBusPropertiesMixin

TpDBusPropertiesMixin — a mixin implementation of the DBus.Properties interface

Synopsis

#include <telepathy-glib/dbus-properties-mixin.h>

enum                TpDBusPropertiesMixinFlags;
                    TpDBusPropertiesMixinIfaceInfo;
                    TpDBusPropertiesMixinPropInfo;
void                tp_svc_interface_set_dbus_properties_info
                                                        (GType g_interface,
                                                         TpDBusPropertiesMixinIfaceInfo *info);

                    TpDBusPropertiesMixinClass;
                    TpDBusPropertiesMixinIfaceImpl;
                    TpDBusPropertiesMixinPropImpl;
void                (*TpDBusPropertiesMixinGetter)      (GObject *object,
                                                         GQuark iface,
                                                         GQuark name,
                                                         GValue *value,
                                                         gpointer getter_data);
void                tp_dbus_properties_mixin_getter_gobject_properties
                                                        (GObject *object,
                                                         GQuark iface,
                                                         GQuark name,
                                                         GValue *value,
                                                         gpointer getter_data);
gboolean            (*TpDBusPropertiesMixinSetter)      (GObject *object,
                                                         GQuark iface,
                                                         GQuark name,
                                                         const GValue *value,
                                                         gpointer setter_data,
                                                         GError **error);
gboolean            tp_dbus_properties_mixin_setter_gobject_properties
                                                        (GObject *object,
                                                         GQuark iface,
                                                         GQuark name,
                                                         const GValue *value,
                                                         gpointer setter_data,
                                                         GError **error);
void                tp_dbus_properties_mixin_class_init (GObjectClass *cls,
                                                         gsize offset);
void                tp_dbus_properties_mixin_implement_interface
                                                        (GObjectClass *cls,
                                                         GQuark iface,
                                                         TpDBusPropertiesMixinGetter getter,
                                                         TpDBusPropertiesMixinSetter setter,
                                                         TpDBusPropertiesMixinPropImpl *props);
void                tp_dbus_properties_mixin_iface_init (gpointer g_iface,
                                                         gpointer iface_data);
gboolean            tp_dbus_properties_mixin_get        (GObject *self,
                                                         const gchar *interface_name,
                                                         const gchar *property_name,
                                                         GValue *value,
                                                         GError **error);
GHashTable *        tp_dbus_properties_mixin_make_properties_hash
                                                        (GObject *object,
                                                         const gchar *first_interface,
                                                         const gchar *first_property,
                                                         ...);

Description

This mixin provides an implementation of the org.freedesktop.DBus.Properties interface. It relies on the auto-generated service-side GInterfaces from telepathy-glib >= 0.7.3, or something similar, to register the abstract properties and their GTypes; classes with the mixin can then register an implementation of the properties.

To register D-Bus properties in a GInterface to be implementable with this mixin, either use the code-generation tools from telepathy-glib >= 0.7.3, or call tp_svc_interface_set_properties_info() from a section of the base_init function that only runs once.

To use this mixin, include a TpDBusPropertiesMixinClass somewhere in your class structure, populate it with pointers to statically allocated (or duplicated and never freed) data, and call tp_dbus_properties_mixin_class_init() from your class_init implementation.

To use this mixin as the implementation of TpSvcDBusProperties, call G_IMPLEMENT_INTERFACE (TP_TYPE_SVC_DBUS_PROPERTIES, tp_dbus_properties_mixin_iface_init) in the fourth argument to G_DEFINE_TYPE_WITH_CODE.

Details

enum TpDBusPropertiesMixinFlags

typedef enum {
    TP_DBUS_PROPERTIES_MIXIN_FLAG_READ = 1,
    TP_DBUS_PROPERTIES_MIXIN_FLAG_WRITE = 2
} TpDBusPropertiesMixinFlags;

Bitfield representing allowed access to a property.

TP_DBUS_PROPERTIES_MIXIN_FLAG_READ

The property can be read using Get and GetAll

TP_DBUS_PROPERTIES_MIXIN_FLAG_WRITE

The property can be written using Set

Since 0.7.3


TpDBusPropertiesMixinIfaceInfo

typedef struct {
    GQuark dbus_interface;
    TpDBusPropertiesMixinPropInfo *props;
} TpDBusPropertiesMixinIfaceInfo;

Semi-abstract description of an interface. Each service GInterface that has properties must have one of these attached to it via tp_svc_interface_set_dbus_properties_info() in its base_init function; service GInterfaces that do not have properties may have one of these with no properties.

This structure must either be statically allocated, or duplicated and never freed, so it always remains valid.

In addition to the documented members, there are two private pointers for future expansion, which must always be initialized to NULL.

GQuark dbus_interface;

Quark representing the interface's name

TpDBusPropertiesMixinPropInfo *props;

Array of property descriptions, terminated by one with name == NULL

Since 0.7.3


TpDBusPropertiesMixinPropInfo

typedef struct {
    GQuark name;
    TpDBusPropertiesMixinFlags flags;
    gchar *dbus_signature;
    GType type;
} TpDBusPropertiesMixinPropInfo;

Semi-abstract description of a property, as attached to a service GInterface. This structure must either be statically allocated, or duplicated and never freed, so it always remains valid.

In addition to the documented members, there are two private pointers for future expansion, which must always be initialized to NULL.

GQuark name;

Quark representing the property's name

TpDBusPropertiesMixinFlags flags;

Flags representing read/write access to the property

gchar *dbus_signature;

The D-Bus signature of the property

GType type;

The GType used in a GValue to implement the property

Since 0.7.3


tp_svc_interface_set_dbus_properties_info ()

void                tp_svc_interface_set_dbus_properties_info
                                                        (GType g_interface,
                                                         TpDBusPropertiesMixinIfaceInfo *info);

Declare that g_interface implements the given D-Bus interface, with the given properties. This may only be called once per GInterface, usually from a section of its base_init function that only runs once.

g_interface :

The GType of a service interface

info :

an interface description

Since 0.7.3


TpDBusPropertiesMixinClass

typedef struct {
    TpDBusPropertiesMixinIfaceImpl *interfaces;
} TpDBusPropertiesMixinClass;

Structure representing all of a class's property implementations. One of these structures may be placed in the layout of an object class structure.

In addition to the documented fields, there are 7 pointers reserved for future use, which must be initialized to NULL.

TpDBusPropertiesMixinIfaceImpl *interfaces;

An array of interface implementations, terminated by one with name equal to NULL

Since 0.7.3


TpDBusPropertiesMixinIfaceImpl

typedef struct {
    const gchar *name;
    TpDBusPropertiesMixinGetter getter;
    TpDBusPropertiesMixinSetter setter;
    TpDBusPropertiesMixinPropImpl *props;
} TpDBusPropertiesMixinIfaceImpl;

Structure representing an implementation of an interface's properties.

In addition to the documented fields, there are four pointers which must be initialized to NULL.

This structure must either be statically allocated, or duplicated and never freed, so it always remains valid.

const gchar *name;

The name of the interface

TpDBusPropertiesMixinGetter getter;

A callback to get the current value of the property, to which the getter_data from each property implementation will be passed

TpDBusPropertiesMixinSetter setter;

A callback to set a new value for the property, to which the setter_data from each property implementation will be passed

TpDBusPropertiesMixinPropImpl *props;

An array of property implementations, terminated by one with name equal to NULL

Since 0.7.3


TpDBusPropertiesMixinPropImpl

typedef struct {
    const gchar *name;
    gpointer getter_data;
    gpointer setter_data;
} TpDBusPropertiesMixinPropImpl;

Structure representing an implementation of a property.

In addition to the documented fields, there are three pointers which must be initialized to NULL.

This structure must either be statically allocated, or duplicated and never freed, so it always remains valid.

const gchar *name;

The name of the property as it appears on D-Bus

gpointer getter_data;

Arbitrary user-supplied data for the getter function

gpointer setter_data;

Arbitrary user-supplied data for the setter function

Since 0.7.3


TpDBusPropertiesMixinGetter ()

void                (*TpDBusPropertiesMixinGetter)      (GObject *object,
                                                         GQuark iface,
                                                         GQuark name,
                                                         GValue *value,
                                                         gpointer getter_data);

Signature of a callback used to get the value of a property.

For simplicity, in this mixin we don't allow getting a property to fail; implementations must always be prepared to return *something*.

object :

The exported object with the properties

iface :

A quark representing the D-Bus interface name

name :

A quark representing the D-Bus property name

value :

A GValue pre-initialized to the right type, into which to put the value

getter_data :

The getter_data from the TpDBusPropertiesMixinPropImpl

tp_dbus_properties_mixin_getter_gobject_properties ()

void                tp_dbus_properties_mixin_getter_gobject_properties
                                                        (GObject *object,
                                                         GQuark iface,
                                                         GQuark name,
                                                         GValue *value,
                                                         gpointer getter_data);

An implementation of TpDBusPropertiesMixinGetter which assumes that the getter_data is the name of a readable GObject property of an appropriate type, and uses it for the value of the D-Bus property.

object :

The exported object with the properties

iface :

A quark representing the D-Bus interface name

name :

A quark representing the D-Bus property name

value :

A GValue pre-initialized to the right type, into which to put the value

getter_data :

The getter_data from the TpDBusPropertiesMixinPropImpl, which must be a string containing the GObject property's name

TpDBusPropertiesMixinSetter ()

gboolean            (*TpDBusPropertiesMixinSetter)      (GObject *object,
                                                         GQuark iface,
                                                         GQuark name,
                                                         const GValue *value,
                                                         gpointer setter_data,
                                                         GError **error);

Signature of a callback used to get the value of a property.

object :

The exported object with the properties

iface :

A quark representing the D-Bus interface name

name :

A quark representing the D-Bus property name

value :

The new value for the property

setter_data :

The setter_data from the TpDBusPropertiesMixinPropImpl

error :

Used to return an error on failure

Returns :

TRUE on success, FALSE (setting error) on failure

tp_dbus_properties_mixin_setter_gobject_properties ()

gboolean            tp_dbus_properties_mixin_setter_gobject_properties
                                                        (GObject *object,
                                                         GQuark iface,
                                                         GQuark name,
                                                         const GValue *value,
                                                         gpointer setter_data,
                                                         GError **error);

An implementation of TpDBusPropertiesMixinSetter which assumes that the setter_data is the name of a writable GObject property of an appropriate type, and sets that property to the given value.

object :

The exported object with the properties

iface :

A quark representing the D-Bus interface name

name :

A quark representing the D-Bus property name

value :

The new value for the property

setter_data :

The setter_data from the TpDBusPropertiesMixinPropImpl, which must be a string containing the GObject property's name

error :

Not used

Returns :

TRUE

tp_dbus_properties_mixin_class_init ()

void                tp_dbus_properties_mixin_class_init (GObjectClass *cls,
                                                         gsize offset);

Initialize the class cls to use the D-Bus Properties mixin. The given struct member, of size sizeof(TpDBusPropertiesMixinClass), will be used to store property implementation information.

Each property and each interface must have been declared as a member of a GInterface implemented by cls, using tp_svc_interface_set_dbus_properties_info().

Before calling this function, the array interfaces must have been placed in the TpDBusPropertiesMixinClass structure; if it would be empty, it may instead be NULL.

This function should be called from the class_init callback in such a way that it will only be called once, even if the class is subclassed.

Changed in 0.7.9: TpDBusPropertiesMixinClass::interfaces may now be NULL, which means that only interfaces whose properties are set up using tp_dbus_properties_mixin_implement_interface() will be used.

Changed in 0.7.15: offset may now be 0, in which case the TpDBusPropertiesMixinClass can be omitted from cls. It is treated as if it were present, but with all fields (including TpDBusPropertiesMixinClass::interfaces) being NULL, so only interfaces whose properties are set using tp_dbus_properties_mixin_implement_interface() will be used.

cls :

a subclass of GObjectClass

offset :

the offset within cls of a TpDBusPropertiesMixinClass structure

Since 0.7.3


tp_dbus_properties_mixin_implement_interface ()

void                tp_dbus_properties_mixin_implement_interface
                                                        (GObjectClass *cls,
                                                         GQuark iface,
                                                         TpDBusPropertiesMixinGetter getter,
                                                         TpDBusPropertiesMixinSetter setter,
                                                         TpDBusPropertiesMixinPropImpl *props);

Declare that, in addition to any interfaces set in tp_dbus_properties_mixin_class_init(), the given class (and its subclasses) will implement the properties of the interface iface using the callbacks getter and setter and the properties given by props.

This function should be called from the class_init callback in such a way that it will only be called once, even if the class is subclassed.

Typically, the static array interfaces in the TpDBusPropertiesMixinClass should be used for interfaces whose properties are implemented directly by the class cls, and this function should be used for interfaces whose properties are implemented by mixins.

It is an error for the same interface to appear in the array interfaces in the TpDBusPropertiesMixinClass, and also be set up by this function.

If a class C and a subclass S both implement the properties of the same interface, only the implementations from the subclass S will be used, regardless of whether the implementations in C and/or S were set up by this function or via the array interfaces in the TpDBusPropertiesMixinClass.

cls :

a subclass of GObjectClass

iface :

a quark representing the the name of the interface to implement

getter :

a callback to get properties on this interface, or NULL if they are all write-only

setter :

a callback to set properties on this interface, or NULL if they are all read-only

props :

an array of TpDBusPropertiesMixinPropImpl representing individual properties, terminated by one with name == NULL

tp_dbus_properties_mixin_iface_init ()

void                tp_dbus_properties_mixin_iface_init (gpointer g_iface,
                                                         gpointer iface_data);

Declare that the DBus.Properties interface represented by g_iface is implemented using this mixin.

g_iface :

a pointer to a TpSvcDBusPropertiesClass structure

iface_data :

ignored

tp_dbus_properties_mixin_get ()

gboolean            tp_dbus_properties_mixin_get        (GObject *self,
                                                         const gchar *interface_name,
                                                         const gchar *property_name,
                                                         GValue *value,
                                                         GError **error);

Initialize value with the type of the property property_name on interface_name, and write the value of that property into it as if by calling the D-Bus method org.freedesktop.DBus.Properties.Get.

If Get would return a D-Bus error, value remains unset and error is filled in instead.

self :

an object with this mixin

interface_name :

a D-Bus interface name

property_name :

a D-Bus property name

value :

an unset GValue (initialized to all zeroes)

error :

used to return an error on failure

Returns :

TRUE (filling value) on success, FALSE (setting error) on failure

Since 0.7.13


tp_dbus_properties_mixin_make_properties_hash ()

GHashTable *        tp_dbus_properties_mixin_make_properties_hash
                                                        (GObject *object,
                                                         const gchar *first_interface,
                                                         const gchar *first_property,
                                                         ...);

Retrieves the values of several D-Bus properties from an object, and builds a hash mapping the fully-qualified name of the property to its value. This is equivalent to calling tp_dbus_properties_mixin_get() for each property and building the table yourself, with the proviso that this function will g_assert() if retrieving a property fails (for instance, because it does not exist).

Additional keys and values can be inserted into the returned hash table; if this is done, the inserted keys and values will be freed when the hash table is destroyed. The keys must be allocated with g_strdup() or equivalent, and the values must be slice-allocated (for instance with tp_g_value_slice_new_string() or a similar function).

Note that in particular, tp_asv_set_string() and similar functions should not be used with this hash table.

object :

an object which uses the D-Bus properties mixin

first_interface :

the interface of the first property to be retrieved

first_property :

the name of the first property to be retrieved

... :

more (interface name, property name) pairs, terminated by NULL.

Returns :

a hash table mapping (gchar *) fully-qualified property names to GValues, which must be freed by the caller (at which point its contents will also be freed).

See Also

TpSvcDBusProperties