GeditMessageBus

GeditMessageBus — internal message communication bus

Synopsis

#include <gedit/gedit-message-bus.h>

                    GeditMessageBus;
void                (*GeditMessageCallback)             (GeditMessageBus *bus,
                                                         GeditMessage *message,
                                                         gpointer userdata);
GeditMessageBus *   gedit_message_bus_get_default       (void);
GeditMessageBus *   gedit_message_bus_new               (void);
GeditMessageType *  gedit_message_bus_lookup            (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method);
GeditMessageType *  gedit_message_bus_register          (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method,
                                                         guint num_optional,
                                                         ...);
void                gedit_message_bus_unregister        (GeditMessageBus *bus,
                                                         GeditMessageType *message_type);
void                gedit_message_bus_unregister_all    (GeditMessageBus *bus,
                                                         const gchar *object_path);
gboolean            gedit_message_bus_is_registered     (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method);
void                gedit_message_bus_foreach           (GeditMessageBus *bus,
                                                         GeditMessageBusForeach func,
                                                         gpointer userdata);
guint               gedit_message_bus_connect           (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method,
                                                         GeditMessageCallback callback,
                                                         gpointer userdata,
                                                         GDestroyNotify destroy_data);
void                gedit_message_bus_disconnect        (GeditMessageBus *bus,
                                                         guint id);
void                gedit_message_bus_disconnect_by_func
                                                        (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method,
                                                         GeditMessageCallback callback,
                                                         gpointer userdata);
void                gedit_message_bus_block             (GeditMessageBus *bus,
                                                         guint id);
void                gedit_message_bus_block_by_func     (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method,
                                                         GeditMessageCallback callback,
                                                         gpointer userdata);
void                gedit_message_bus_unblock           (GeditMessageBus *bus,
                                                         guint id);
void                gedit_message_bus_unblock_by_func   (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method,
                                                         GeditMessageCallback callback,
                                                         gpointer userdata);
void                gedit_message_bus_send_message      (GeditMessageBus *bus,
                                                         GeditMessage *message);
void                gedit_message_bus_send_message_sync (GeditMessageBus *bus,
                                                         GeditMessage *message);
void                gedit_message_bus_send              (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method,
                                                         ...);
GeditMessage *      gedit_message_bus_send_sync         (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method,
                                                         ...);

Object Hierarchy

  GObject
   +----GeditMessageBus

Signals

  "dispatch"                                       : Run Last
  "registered"                                     : Run Last
  "unregistered"                                   : Run Last

Description

gedit has a communication bus very similar to DBus. Its primary use is to allow easy communication between plugins, but it can also be used to expose gedit functionality to external applications by providing DBus bindings for the internal gedit message bus.

There are two different communication busses available. The default bus (see gedit_message_bus_get_default()) is an application wide communication bus. In addition, each GeditWindow has a separate, private bus (see gedit_window_get_message_bus()). This makes it easier for plugins to communicate to other plugins in the same window.

The concept of the message bus is very simple. You can register a message type on the bus, specified as a Method at a specific Object Path with a certain set of Method Arguments. You can then connect callback functions for this message type on the bus. Whenever a message with the Object Path and Method for which callbacks are connected is sent over the bus, the callbacks are called. There is no distinction between Methods and Signals (signals are simply messages where sender and receiver have switched places).

Example 1. Registering a message type

GeditMessageBus *bus = gedit_message_bus_get_default ();

// Register 'method' at '/plugins/example' with one required
// string argument 'arg1'
GeditMessageType *message_type = gedit_message_bus_register ("/plugins/example", "method", 
                                                             0, 
                                                             "arg1", G_TYPE_STRING,
                                                             NULL);


Example 2. Connecting a callback

static void
example_method_cb (GeditMessageBus *bus,
                   GeditMessage    *message,
                   gpointer         userdata)
{
	gchar *arg1 = NULL;

	gedit_message_get (message, "arg1", &arg1, NULL);
	g_message ("Evoked /plugins/example.method with: %s", arg1);
	g_free (arg1);
}

GeditMessageBus *bus = gedit_message_bus_get_default ();

guint id = gedit_message_bus_connect (bus, 
                                      "/plugins/example", "method",
                                      example_method_cb,
                                      NULL,
                                      NULL);


Example 3. Sending a message

GeditMessageBus *bus = gedit_message_bus_get_default ();

gedit_message_bus_send (bus, 
                        "/plugins/example", "method", 
                        "arg1", "Hello World", 
                        NULL);


Details

GeditMessageBus

typedef struct _GeditMessageBus GeditMessageBus;

GeditMessageCallback ()

void                (*GeditMessageCallback)             (GeditMessageBus *bus,
                                                         GeditMessage *message,
                                                         gpointer userdata);

Callback signature used for connecting callback functions to be called when a message is received (see gedit_message_bus_connect()).

bus :

 the GeditMessageBus on which the message was sent

message :

 the GeditMessage which was sent

userdata :

 the supplied user data when connecting the callback

gedit_message_bus_get_default ()

GeditMessageBus *   gedit_message_bus_get_default       (void);

Get the default application GeditMessageBus.

Returns :

 the default GeditMessageBus

gedit_message_bus_new ()

GeditMessageBus *   gedit_message_bus_new               (void);

Create a new message bus. Use gedit_message_bus_get_default() to get the default, application wide, message bus. Creating a new bus is useful for associating a specific bus with for instance a GeditWindow.

Returns :

 a new GeditMessageBus

gedit_message_bus_lookup ()

GeditMessageType *  gedit_message_bus_lookup            (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method);

Get the registered GeditMessageType for method at object_path. The returned GeditMessageType is owned by the bus and should not be unreffed.

bus :

 a GeditMessageBus

object_path :

 the object path

method :

 the method

Returns :

 the registered GeditMessageType or NULL if no message type is registered for method at object_path

gedit_message_bus_register ()

GeditMessageType *  gedit_message_bus_register          (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method,
                                                         guint num_optional,
                                                         ...);

Register a message on the bus. A message must be registered on the bus before it can be send. This function registers the type arguments for method at object_path. The arguments are specified with the variable arguments which should contain pairs of const gchar *key and GType terminated by NULL. The last num_optional arguments are registered as optional (and are thus not required when sending a message).

This function emits a "registered" signal.

bus :

 a GeditMessageBus

object_path :

 the object path

method :

 the method to register

num_optional :

 the number of optional arguments

... :

 NULL terminated list of key/gtype method argument pairs

Returns :

 the registered GeditMessageType. The returned reference is owned by the bus. If you want to keep it alive after unregistering, use gedit_message_type_ref().

gedit_message_bus_unregister ()

void                gedit_message_bus_unregister        (GeditMessageBus *bus,
                                                         GeditMessageType *message_type);

Unregisters a previously registered message type. This is especially useful for plugins which should unregister message types when they are deactivated.

This function emits the "unregistered" signal.

bus :

 a GeditMessageBus

message_type :

 the GeditMessageType to unregister

gedit_message_bus_unregister_all ()

void                gedit_message_bus_unregister_all    (GeditMessageBus *bus,
                                                         const gchar *object_path);

Unregisters all message types for object_path. This is especially useful for plugins which should unregister message types when they are deactivated.

This function emits the "unregistered" signal for all unregistered message types.

bus :

 a GeditMessageBus

object_path :

 the object path

gedit_message_bus_is_registered ()

gboolean            gedit_message_bus_is_registered     (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method);

Check whether a message type method at object_path is registered on the bus.

bus :

 a GeditMessageBus

object_path :

 the object path

method :

 the method

Returns :

 TRUE if the method at object_path is a registered message type on the bus

gedit_message_bus_foreach ()

void                gedit_message_bus_foreach           (GeditMessageBus *bus,
                                                         GeditMessageBusForeach func,
                                                         gpointer userdata);

Calls func for each message type registered on the bus

bus :

 the GeditMessagebus

func :

 the callback function

userdata :

 the user data to supply to the callback function

gedit_message_bus_connect ()

guint               gedit_message_bus_connect           (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method,
                                                         GeditMessageCallback callback,
                                                         gpointer userdata,
                                                         GDestroyNotify destroy_data);

Connect a callback handler to be evoked when message method at object_path is sent over the bus.

bus :

 a GeditMessageBus

object_path :

 the object path

method :

 the method

callback :

 function to be called when message method at object_path is sent

userdata :

 userdata to use for the callback

destroy_data :

 function to evoke with userdata as argument when userdata needs to be freed

Returns :

 the callback identifier

gedit_message_bus_disconnect ()

void                gedit_message_bus_disconnect        (GeditMessageBus *bus,
                                                         guint id);

Disconnects a previously connected message callback.

bus :

 a GeditMessageBus

id :

 the callback id as returned by gedit_message_bus_connect()

gedit_message_bus_disconnect_by_func ()

void                gedit_message_bus_disconnect_by_func
                                                        (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method,
                                                         GeditMessageCallback callback,
                                                         gpointer userdata);

Disconnects a previously connected message callback by matching the provided callback function and userdata. See also gedit_message_bus_disconnect().

bus :

 a GeditMessageBus

object_path :

 the object path

method :

 the method

callback :

 the connected callback

userdata :

 the userdata with which the callback was connected

gedit_message_bus_block ()

void                gedit_message_bus_block             (GeditMessageBus *bus,
                                                         guint id);

Blocks evoking the callback specified by id. Unblock the callback by using gedit_message_bus_unblock().

bus :

 a GeditMessageBus

id :

 the callback id

gedit_message_bus_block_by_func ()

void                gedit_message_bus_block_by_func     (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method,
                                                         GeditMessageCallback callback,
                                                         gpointer userdata);

Blocks evoking the callback that matches provided callback and userdata. Unblock the callback using gedit_message_unblock_by_func().

bus :

 a GeditMessageBus

object_path :

 the object path

method :

 the method

callback :

 the callback to block

userdata :

 the userdata with which the callback was connected

gedit_message_bus_unblock ()

void                gedit_message_bus_unblock           (GeditMessageBus *bus,
                                                         guint id);

Unblocks the callback specified by id.

bus :

 a GeditMessageBus

id :

 the callback id

gedit_message_bus_unblock_by_func ()

void                gedit_message_bus_unblock_by_func   (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method,
                                                         GeditMessageCallback callback,
                                                         gpointer userdata);

Unblocks the callback that matches provided callback and userdata.

bus :

 a GeditMessageBus

object_path :

 the object path

method :

 the method

callback :

 the callback to block

userdata :

 the userdata with which the callback was connected

gedit_message_bus_send_message ()

void                gedit_message_bus_send_message      (GeditMessageBus *bus,
                                                         GeditMessage *message);

This sends the provided message asynchronously over the bus. To send a message synchronously, use gedit_message_bus_send_message_sync(). The convenience function gedit_message_bus_send() can be used to easily send a message without constructing the message object explicitly first.

bus :

 a GeditMessageBus

message :

 the message to send

gedit_message_bus_send_message_sync ()

void                gedit_message_bus_send_message_sync (GeditMessageBus *bus,
                                                         GeditMessage *message);

This sends the provided message synchronously over the bus. To send a message asynchronously, use gedit_message_bus_send_message(). The convenience function gedit_message_bus_send_sync() can be used to easily send a message without constructing the message object explicitly first.

bus :

 a GeditMessageBus

message :

 the message to send

gedit_message_bus_send ()

void                gedit_message_bus_send              (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method,
                                                         ...);

This provides a convenient way to quickly send a message method at object_path asynchronously over the bus. The variable argument list specifies key (string) value pairs used to construct the message arguments. To send a message synchronously use gedit_message_bus_send_sync().

bus :

 a GeditMessageBus

object_path :

 the object path

method :

 the method

... :

 NULL terminated list of key/value pairs

gedit_message_bus_send_sync ()

GeditMessage *      gedit_message_bus_send_sync         (GeditMessageBus *bus,
                                                         const gchar *object_path,
                                                         const gchar *method,
                                                         ...);

This provides a convenient way to quickly send a message method at object_path synchronously over the bus. The variable argument list specifies key (string) value pairs used to construct the message arguments. To send a message asynchronously use gedit_message_bus_send().

bus :

 a GeditMessageBus

object_path :

 the object path

method :

 the method

... :

 NULL terminated list of key/value pairs

Returns :

 the constructed GeditMessage. The caller owns a reference to the GeditMessage and should call g_object_unref() when it is no longer needed

Signal Details

The "dispatch" signal

void                user_function                      (GeditMessageBus *bus,
                                                        GeditMessage    *message,
                                                        gpointer         user_data)      : Run Last

The "dispatch" signal is emitted when a message is to be dispatched. The message is dispatched in the default handler of this signal. Primary use of this signal is to customize the dispatch of a message (for instance to automatically dispatch all messages over DBus). 2

bus :

 a GeditMessageBus

message :

 the GeditMessage to dispatch

user_data :

 user data set when the signal handler was connected.

The "registered" signal

void                user_function                      (GeditMessageBus  *bus,
                                                        GeditMessageType *message_type,
                                                        gpointer          user_data)         : Run Last

The "registered" signal is emitted when a message has been registered on the bus.

bus :

 a GeditMessageBus

message_type :

 the registered GeditMessageType

user_data :

 user data set when the signal handler was connected.

The "unregistered" signal

void                user_function                      (GeditMessageBus  *bus,
                                                        GeditMessageType *message_type,
                                                        gpointer          user_data)         : Run Last

The "unregistered" signal is emitted when a message has been unregistered from the bus.

bus :

 a GeditMessageBus

message_type :

 the unregistered GeditMessageType

user_data :

 user data set when the signal handler was connected.
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