1/* GObject - GLib Type, Object, Parameter and Signal Library
2 * Copyright (C) 2000-2001 Red Hat, Inc.
3 * Copyright (C) 2005 Imendio AB
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2.1 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General
16 * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
17 */
18#ifndef __G_CLOSURE_H__
19#define __G_CLOSURE_H__
20
21#if !defined (__GLIB_GOBJECT_H_INSIDE__) && !defined (GOBJECT_COMPILATION)
22#error "Only <glib-object.h> can be included directly."
23#endif
24
25#include <gobject/gtype.h>
26
27G_BEGIN_DECLS
28
29/* --- defines --- */
30/**
31 * G_CLOSURE_NEEDS_MARSHAL:
32 * @closure: a #GClosure
33 *
34 * Check if the closure still needs a marshaller. See g_closure_set_marshal().
35 *
36 * Returns: %TRUE if a #GClosureMarshal marshaller has not yet been set on
37 * @closure.
38 */
39#define G_CLOSURE_NEEDS_MARSHAL(closure) (((GClosure*) (closure))->marshal == NULL)
40/**
41 * G_CLOSURE_N_NOTIFIERS:
42 * @cl: a #GClosure
43 *
44 * Get the total number of notifiers connected with the closure @cl.
45 *
46 * The count includes the meta marshaller, the finalize and invalidate notifiers
47 * and the marshal guards. Note that each guard counts as two notifiers.
48 * See g_closure_set_meta_marshal(), g_closure_add_finalize_notifier(),
49 * g_closure_add_invalidate_notifier() and g_closure_add_marshal_guards().
50 *
51 * Returns: number of notifiers
52 */
53#define G_CLOSURE_N_NOTIFIERS(cl) (((cl)->n_guards << 1L) + \
54 (cl)->n_fnotifiers + (cl)->n_inotifiers)
55/**
56 * G_CCLOSURE_SWAP_DATA:
57 * @cclosure: a #GCClosure
58 *
59 * Checks whether the user data of the #GCClosure should be passed as the
60 * first parameter to the callback. See g_cclosure_new_swap().
61 *
62 * Returns: %TRUE if data has to be swapped.
63 */
64#define G_CCLOSURE_SWAP_DATA(cclosure) (((GClosure*) (cclosure))->derivative_flag)
65/**
66 * G_CALLBACK:
67 * @f: a function pointer.
68 *
69 * Cast a function pointer to a #GCallback.
70 */
71#define G_CALLBACK(f) ((GCallback) (f))
72
73
74/* -- typedefs --- */
75typedef struct _GClosure GClosure;
76typedef struct _GClosureNotifyData GClosureNotifyData;
77
78/**
79 * GCallback:
80 *
81 * The type used for callback functions in structure definitions and function
82 * signatures.
83 *
84 * This doesn't mean that all callback functions must take no parameters and
85 * return void. The required signature of a callback function is determined by
86 * the context in which is used (e.g. the signal to which it is connected).
87 *
88 * Use G_CALLBACK() to cast the callback function to a #GCallback.
89 */
90typedef void (*GCallback) (void);
91/**
92 * GClosureNotify:
93 * @data: data specified when registering the notification callback
94 * @closure: the #GClosure on which the notification is emitted
95 *
96 * The type used for the various notification callbacks which can be registered
97 * on closures.
98 */
99typedef void (*GClosureNotify) (gpointer data,
100 GClosure *closure);
101/**
102 * GClosureMarshal:
103 * @closure: the #GClosure to which the marshaller belongs
104 * @return_value: (nullable): a #GValue to store the return
105 * value. May be %NULL if the callback of @closure doesn't return a
106 * value.
107 * @n_param_values: the length of the @param_values array
108 * @param_values: (array length=n_param_values): an array of
109 * #GValues holding the arguments on which to invoke the
110 * callback of @closure
111 * @invocation_hint: (nullable): the invocation hint given as the
112 * last argument to g_closure_invoke()
113 * @marshal_data: (nullable): additional data specified when
114 * registering the marshaller, see g_closure_set_marshal() and
115 * g_closure_set_meta_marshal()
116 *
117 * The type used for marshaller functions.
118 */
119typedef void (*GClosureMarshal) (GClosure *closure,
120 GValue *return_value,
121 guint n_param_values,
122 const GValue *param_values,
123 gpointer invocation_hint,
124 gpointer marshal_data);
125
126/**
127 * GVaClosureMarshal:
128 * @closure: the #GClosure to which the marshaller belongs
129 * @return_value: (nullable): a #GValue to store the return
130 * value. May be %NULL if the callback of @closure doesn't return a
131 * value.
132 * @instance: (type GObject.TypeInstance): the instance on which the closure is
133 * invoked.
134 * @args: va_list of arguments to be passed to the closure.
135 * @marshal_data: (nullable): additional data specified when
136 * registering the marshaller, see g_closure_set_marshal() and
137 * g_closure_set_meta_marshal()
138 * @n_params: the length of the @param_types array
139 * @param_types: (array length=n_params): the #GType of each argument from
140 * @args.
141 *
142 * This is the signature of va_list marshaller functions, an optional
143 * marshaller that can be used in some situations to avoid
144 * marshalling the signal argument into GValues.
145 */
146typedef void (* GVaClosureMarshal) (GClosure *closure,
147 GValue *return_value,
148 gpointer instance,
149 va_list args,
150 gpointer marshal_data,
151 int n_params,
152 GType *param_types);
153
154/**
155 * GCClosure:
156 * @closure: the #GClosure
157 * @callback: the callback function
158 *
159 * A #GCClosure is a specialization of #GClosure for C function callbacks.
160 */
161typedef struct _GCClosure GCClosure;
162
163
164/* --- structures --- */
165struct _GClosureNotifyData
166{
167 gpointer data;
168 GClosureNotify notify;
169};
170/**
171 * GClosure:
172 * @in_marshal: Indicates whether the closure is currently being invoked with
173 * g_closure_invoke()
174 * @is_invalid: Indicates whether the closure has been invalidated by
175 * g_closure_invalidate()
176 *
177 * A #GClosure represents a callback supplied by the programmer.
178 */
179struct _GClosure
180{
181 /*< private >*/
182 guint ref_count : 15; /* (atomic) */
183 /* meta_marshal is not used anymore but must be zero for historical reasons
184 as it was exposed in the G_CLOSURE_N_NOTIFIERS macro */
185 guint meta_marshal_nouse : 1; /* (atomic) */
186 guint n_guards : 1; /* (atomic) */
187 guint n_fnotifiers : 2; /* finalization notifiers (atomic) */
188 guint n_inotifiers : 8; /* invalidation notifiers (atomic) */
189 guint in_inotify : 1; /* (atomic) */
190 guint floating : 1; /* (atomic) */
191 /*< protected >*/
192 guint derivative_flag : 1; /* (atomic) */
193 /*< public >*/
194 guint in_marshal : 1; /* (atomic) */
195 guint is_invalid : 1; /* (atomic) */
196
197 /*< private >*/ void (*marshal) (GClosure *closure,
198 GValue /*out*/ *return_value,
199 guint n_param_values,
200 const GValue *param_values,
201 gpointer invocation_hint,
202 gpointer marshal_data);
203 /*< protected >*/ gpointer data;
204
205 /*< private >*/ GClosureNotifyData *notifiers;
206
207 /* invariants/constraints:
208 * - ->marshal and ->data are _invalid_ as soon as ->is_invalid==TRUE
209 * - invocation of all inotifiers occurs prior to fnotifiers
210 * - order of inotifiers is random
211 * inotifiers may _not_ free/invalidate parameter values (e.g. ->data)
212 * - order of fnotifiers is random
213 * - each notifier may only be removed before or during its invocation
214 * - reference counting may only happen prior to fnotify invocation
215 * (in that sense, fnotifiers are really finalization handlers)
216 */
217};
218/* closure for C function calls, callback() is the user function
219 */
220struct _GCClosure
221{
222 GClosure closure;
223 gpointer callback;
224};
225
226
227/* --- prototypes --- */
228GLIB_AVAILABLE_IN_ALL
229GClosure* g_cclosure_new (GCallback callback_func,
230 gpointer user_data,
231 GClosureNotify destroy_data);
232GLIB_AVAILABLE_IN_ALL
233GClosure* g_cclosure_new_swap (GCallback callback_func,
234 gpointer user_data,
235 GClosureNotify destroy_data);
236GLIB_AVAILABLE_IN_ALL
237GClosure* g_signal_type_cclosure_new (GType itype,
238 guint struct_offset);
239
240
241/* --- prototypes --- */
242GLIB_AVAILABLE_IN_ALL
243GClosure* g_closure_ref (GClosure *closure);
244GLIB_AVAILABLE_IN_ALL
245void g_closure_sink (GClosure *closure);
246GLIB_AVAILABLE_IN_ALL
247void g_closure_unref (GClosure *closure);
248/* intimidating */
249GLIB_AVAILABLE_IN_ALL
250GClosure* g_closure_new_simple (guint sizeof_closure,
251 gpointer data);
252GLIB_AVAILABLE_IN_ALL
253void g_closure_add_finalize_notifier (GClosure *closure,
254 gpointer notify_data,
255 GClosureNotify notify_func);
256GLIB_AVAILABLE_IN_ALL
257void g_closure_remove_finalize_notifier (GClosure *closure,
258 gpointer notify_data,
259 GClosureNotify notify_func);
260GLIB_AVAILABLE_IN_ALL
261void g_closure_add_invalidate_notifier (GClosure *closure,
262 gpointer notify_data,
263 GClosureNotify notify_func);
264GLIB_AVAILABLE_IN_ALL
265void g_closure_remove_invalidate_notifier (GClosure *closure,
266 gpointer notify_data,
267 GClosureNotify notify_func);
268GLIB_AVAILABLE_IN_ALL
269void g_closure_add_marshal_guards (GClosure *closure,
270 gpointer pre_marshal_data,
271 GClosureNotify pre_marshal_notify,
272 gpointer post_marshal_data,
273 GClosureNotify post_marshal_notify);
274GLIB_AVAILABLE_IN_ALL
275void g_closure_set_marshal (GClosure *closure,
276 GClosureMarshal marshal);
277GLIB_AVAILABLE_IN_ALL
278void g_closure_set_meta_marshal (GClosure *closure,
279 gpointer marshal_data,
280 GClosureMarshal meta_marshal);
281GLIB_AVAILABLE_IN_ALL
282void g_closure_invalidate (GClosure *closure);
283GLIB_AVAILABLE_IN_ALL
284void g_closure_invoke (GClosure *closure,
285 GValue /*out*/ *return_value,
286 guint n_param_values,
287 const GValue *param_values,
288 gpointer invocation_hint);
289
290/* FIXME:
291 OK: data_object::destroy -> closure_invalidate();
292 MIS: closure_invalidate() -> disconnect(closure);
293 MIS: disconnect(closure) -> (unlink) closure_unref();
294 OK: closure_finalize() -> g_free (data_string);
295
296 random remarks:
297 - need marshaller repo with decent aliasing to base types
298 - provide marshaller collection, virtually covering anything out there
299*/
300
301GLIB_AVAILABLE_IN_ALL
302void g_cclosure_marshal_generic (GClosure *closure,
303 GValue *return_gvalue,
304 guint n_param_values,
305 const GValue *param_values,
306 gpointer invocation_hint,
307 gpointer marshal_data);
308
309GLIB_AVAILABLE_IN_ALL
310void g_cclosure_marshal_generic_va (GClosure *closure,
311 GValue *return_value,
312 gpointer instance,
313 va_list args_list,
314 gpointer marshal_data,
315 int n_params,
316 GType *param_types);
317
318
319G_END_DECLS
320
321#endif /* __G_CLOSURE_H__ */
322

source code of include/glib-2.0/gobject/gclosure.h