1 /*
2  * This file is part of gtkD.
3  *
4  * gtkD is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU Lesser General Public License
6  * as published by the Free Software Foundation; either version 3
7  * of the License, or (at your option) any later version, with
8  * some exceptions, please read the COPYING file.
9  *
10  * gtkD 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
13  * GNU Lesser General Public License for more details.
14  *
15  * You should have received a copy of the GNU Lesser General Public License
16  * along with gtkD; if not, write to the Free Software
17  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110, USA
18  */
19 
20 // generated automatically - do not change
21 // find conversion definition on APILookup.txt
22 // implement new conversion functionalities on the wrap.utils pakage
23 
24 
25 module gobject.Closure;
26 
27 private import glib.ConstructionException;
28 private import glib.Source;
29 private import gobject.ObjectG;
30 private import gobject.Value;
31 private import gobject.c.functions;
32 public  import gobject.c.types;
33 public  import gtkc.gobjecttypes;
34 private import gtkd.Loader;
35 
36 
37 /**
38  * A #GClosure represents a callback supplied by the programmer. It
39  * will generally comprise a function of some kind and a marshaller
40  * used to call it. It is the responsibility of the marshaller to
41  * convert the arguments for the invocation from #GValues into
42  * a suitable form, perform the callback on the converted arguments,
43  * and transform the return value back into a #GValue.
44  * 
45  * In the case of C programs, a closure usually just holds a pointer
46  * to a function and maybe a data argument, and the marshaller
47  * converts between #GValue and native C types. The GObject
48  * library provides the #GCClosure type for this purpose. Bindings for
49  * other languages need marshallers which convert between #GValues
50  * and suitable representations in the runtime of the language in
51  * order to use functions written in that language as callbacks. Use
52  * g_closure_set_marshal() to set the marshaller on such a custom
53  * closure implementation.
54  * 
55  * Within GObject, closures play an important role in the
56  * implementation of signals. When a signal is registered, the
57  * @c_marshaller argument to g_signal_new() specifies the default C
58  * marshaller for any closure which is connected to this
59  * signal. GObject provides a number of C marshallers for this
60  * purpose, see the g_cclosure_marshal_*() functions. Additional C
61  * marshallers can be generated with the [glib-genmarshal][glib-genmarshal]
62  * utility.  Closures can be explicitly connected to signals with
63  * g_signal_connect_closure(), but it usually more convenient to let
64  * GObject create a closure automatically by using one of the
65  * g_signal_connect_*() functions which take a callback function/user
66  * data pair.
67  * 
68  * Using closures has a number of important advantages over a simple
69  * callback function/data pointer combination:
70  * 
71  * - Closures allow the callee to get the types of the callback parameters,
72  * which means that language bindings don't have to write individual glue
73  * for each callback type.
74  * 
75  * - The reference counting of #GClosure makes it easy to handle reentrancy
76  * right; if a callback is removed while it is being invoked, the closure
77  * and its parameters won't be freed until the invocation finishes.
78  * 
79  * - g_closure_invalidate() and invalidation notifiers allow callbacks to be
80  * automatically removed when the objects they point to go away.
81  */
82 public class Closure
83 {
84 	/** the main Gtk struct */
85 	protected GClosure* gClosure;
86 	protected bool ownedRef;
87 
88 	/** Get the main Gtk struct */
89 	public GClosure* getClosureStruct(bool transferOwnership = false)
90 	{
91 		if (transferOwnership)
92 			ownedRef = false;
93 		return gClosure;
94 	}
95 
96 	/** the main Gtk struct as a void* */
97 	protected void* getStruct()
98 	{
99 		return cast(void*)gClosure;
100 	}
101 
102 	/**
103 	 * Sets our main struct and passes it to the parent class.
104 	 */
105 	public this (GClosure* gClosure, bool ownedRef = false)
106 	{
107 		this.gClosure = gClosure;
108 		this.ownedRef = ownedRef;
109 	}
110 
111 	~this ()
112 	{
113 		if ( Linker.isLoaded(LIBRARY_GOBJECT) && ownedRef )
114 			g_closure_unref(gClosure);
115 	}
116 
117 
118 	/** */
119 	public static GType getType()
120 	{
121 		return g_closure_get_type();
122 	}
123 
124 	/**
125 	 * A variant of g_closure_new_simple() which stores @object in the
126 	 * @data field of the closure and calls g_object_watch_closure() on
127 	 * @object and the created closure. This function is mainly useful
128 	 * when implementing new types of closures.
129 	 *
130 	 * Params:
131 	 *     sizeofClosure = the size of the structure to allocate, must be at least
132 	 *         `sizeof (GClosure)`
133 	 *     object = a #GObject pointer to store in the @data field of the newly
134 	 *         allocated #GClosure
135 	 *
136 	 * Returns: a newly allocated #GClosure
137 	 *
138 	 * Throws: ConstructionException GTK+ fails to create the object.
139 	 */
140 	public this(uint sizeofClosure, ObjectG object)
141 	{
142 		auto p = g_closure_new_object(sizeofClosure, (object is null) ? null : object.getObjectGStruct());
143 
144 		if(p is null)
145 		{
146 			throw new ConstructionException("null returned by new_object");
147 		}
148 
149 		this(cast(GClosure*) p);
150 	}
151 
152 	/**
153 	 * Allocates a struct of the given size and initializes the initial
154 	 * part as a #GClosure. This function is mainly useful when
155 	 * implementing new types of closures.
156 	 *
157 	 * |[<!-- language="C" -->
158 	 * typedef struct _MyClosure MyClosure;
159 	 * struct _MyClosure
160 	 * {
161 	 * GClosure closure;
162 	 * // extra data goes here
163 	 * };
164 	 *
165 	 * static void
166 	 * my_closure_finalize (gpointer  notify_data,
167 	 * GClosure *closure)
168 	 * {
169 	 * MyClosure *my_closure = (MyClosure *)closure;
170 	 *
171 	 * // free extra data here
172 	 * }
173 	 *
174 	 * MyClosure *my_closure_new (gpointer data)
175 	 * {
176 	 * GClosure *closure;
177 	 * MyClosure *my_closure;
178 	 *
179 	 * closure = g_closure_new_simple (sizeof (MyClosure), data);
180 	 * my_closure = (MyClosure *) closure;
181 	 *
182 	 * // initialize extra data here
183 	 *
184 	 * g_closure_add_finalize_notifier (closure, notify_data,
185 	 * my_closure_finalize);
186 	 * return my_closure;
187 	 * }
188 	 * ]|
189 	 *
190 	 * Params:
191 	 *     sizeofClosure = the size of the structure to allocate, must be at least
192 	 *         `sizeof (GClosure)`
193 	 *     data = data to store in the @data field of the newly allocated #GClosure
194 	 *
195 	 * Returns: a floating reference to a new #GClosure
196 	 *
197 	 * Throws: ConstructionException GTK+ fails to create the object.
198 	 */
199 	public this(uint sizeofClosure, void* data)
200 	{
201 		auto p = g_closure_new_simple(sizeofClosure, data);
202 
203 		if(p is null)
204 		{
205 			throw new ConstructionException("null returned by new_simple");
206 		}
207 
208 		this(cast(GClosure*) p);
209 	}
210 
211 	/**
212 	 * Registers a finalization notifier which will be called when the
213 	 * reference count of @closure goes down to 0. Multiple finalization
214 	 * notifiers on a single closure are invoked in unspecified order. If
215 	 * a single call to g_closure_unref() results in the closure being
216 	 * both invalidated and finalized, then the invalidate notifiers will
217 	 * be run before the finalize notifiers.
218 	 *
219 	 * Params:
220 	 *     notifyData = data to pass to @notify_func
221 	 *     notifyFunc = the callback function to register
222 	 */
223 	public void addFinalizeNotifier(void* notifyData, GClosureNotify notifyFunc)
224 	{
225 		g_closure_add_finalize_notifier(gClosure, notifyData, notifyFunc);
226 	}
227 
228 	/**
229 	 * Registers an invalidation notifier which will be called when the
230 	 * @closure is invalidated with g_closure_invalidate(). Invalidation
231 	 * notifiers are invoked before finalization notifiers, in an
232 	 * unspecified order.
233 	 *
234 	 * Params:
235 	 *     notifyData = data to pass to @notify_func
236 	 *     notifyFunc = the callback function to register
237 	 */
238 	public void addInvalidateNotifier(void* notifyData, GClosureNotify notifyFunc)
239 	{
240 		g_closure_add_invalidate_notifier(gClosure, notifyData, notifyFunc);
241 	}
242 
243 	/**
244 	 * Adds a pair of notifiers which get invoked before and after the
245 	 * closure callback, respectively. This is typically used to protect
246 	 * the extra arguments for the duration of the callback. See
247 	 * g_object_watch_closure() for an example of marshal guards.
248 	 *
249 	 * Params:
250 	 *     preMarshalData = data to pass
251 	 *         to @pre_marshal_notify
252 	 *     preMarshalNotify = a function to call before the closure callback
253 	 *     postMarshalData = data to pass
254 	 *         to @post_marshal_notify
255 	 *     postMarshalNotify = a function to call after the closure callback
256 	 */
257 	public void addMarshalGuards(void* preMarshalData, GClosureNotify preMarshalNotify, void* postMarshalData, GClosureNotify postMarshalNotify)
258 	{
259 		g_closure_add_marshal_guards(gClosure, preMarshalData, preMarshalNotify, postMarshalData, postMarshalNotify);
260 	}
261 
262 	/**
263 	 * Sets a flag on the closure to indicate that its calling
264 	 * environment has become invalid, and thus causes any future
265 	 * invocations of g_closure_invoke() on this @closure to be
266 	 * ignored. Also, invalidation notifiers installed on the closure will
267 	 * be called at this point. Note that unless you are holding a
268 	 * reference to the closure yourself, the invalidation notifiers may
269 	 * unref the closure and cause it to be destroyed, so if you need to
270 	 * access the closure after calling g_closure_invalidate(), make sure
271 	 * that you've previously called g_closure_ref().
272 	 *
273 	 * Note that g_closure_invalidate() will also be called when the
274 	 * reference count of a closure drops to zero (unless it has already
275 	 * been invalidated before).
276 	 */
277 	public void invalidate()
278 	{
279 		g_closure_invalidate(gClosure);
280 	}
281 
282 	/**
283 	 * Invokes the closure, i.e. executes the callback represented by the @closure.
284 	 *
285 	 * Params:
286 	 *     returnValue = a #GValue to store the return
287 	 *         value. May be %NULL if the callback of @closure
288 	 *         doesn't return a value.
289 	 *     paramValues = an array of
290 	 *         #GValues holding the arguments on which to
291 	 *         invoke the callback of @closure
292 	 *     invocationHint = a context-dependent invocation hint
293 	 */
294 	public void invoke(ref Value returnValue, Value[] paramValues, void* invocationHint)
295 	{
296 		GValue[] paramValuesArray = new GValue[paramValues.length];
297 		for ( int i = 0; i < paramValues.length; i++ )
298 		{
299 			paramValuesArray[i] = *(paramValues[i].getValueStruct());
300 		}
301 
302 		g_closure_invoke(gClosure, (returnValue is null) ? null : returnValue.getValueStruct(), cast(uint)paramValues.length, paramValuesArray.ptr, invocationHint);
303 	}
304 
305 	alias doref = ref_;
306 	/**
307 	 * Increments the reference count on a closure to force it staying
308 	 * alive while the caller holds a pointer to it.
309 	 *
310 	 * Returns: The @closure passed in, for convenience
311 	 */
312 	public Closure ref_()
313 	{
314 		auto p = g_closure_ref(gClosure);
315 
316 		if(p is null)
317 		{
318 			return null;
319 		}
320 
321 		return ObjectG.getDObject!(Closure)(cast(GClosure*) p);
322 	}
323 
324 	/**
325 	 * Removes a finalization notifier.
326 	 *
327 	 * Notice that notifiers are automatically removed after they are run.
328 	 *
329 	 * Params:
330 	 *     notifyData = data which was passed to g_closure_add_finalize_notifier()
331 	 *         when registering @notify_func
332 	 *     notifyFunc = the callback function to remove
333 	 */
334 	public void removeFinalizeNotifier(void* notifyData, GClosureNotify notifyFunc)
335 	{
336 		g_closure_remove_finalize_notifier(gClosure, notifyData, notifyFunc);
337 	}
338 
339 	/**
340 	 * Removes an invalidation notifier.
341 	 *
342 	 * Notice that notifiers are automatically removed after they are run.
343 	 *
344 	 * Params:
345 	 *     notifyData = data which was passed to g_closure_add_invalidate_notifier()
346 	 *         when registering @notify_func
347 	 *     notifyFunc = the callback function to remove
348 	 */
349 	public void removeInvalidateNotifier(void* notifyData, GClosureNotify notifyFunc)
350 	{
351 		g_closure_remove_invalidate_notifier(gClosure, notifyData, notifyFunc);
352 	}
353 
354 	/**
355 	 * Sets the marshaller of @closure. The `marshal_data`
356 	 * of @marshal provides a way for a meta marshaller to provide additional
357 	 * information to the marshaller. (See g_closure_set_meta_marshal().) For
358 	 * GObject's C predefined marshallers (the g_cclosure_marshal_*()
359 	 * functions), what it provides is a callback function to use instead of
360 	 * @closure->callback.
361 	 *
362 	 * Params:
363 	 *     marshal = a #GClosureMarshal function
364 	 */
365 	public void setMarshal(GClosureMarshal marshal)
366 	{
367 		g_closure_set_marshal(gClosure, marshal);
368 	}
369 
370 	/**
371 	 * Sets the meta marshaller of @closure.  A meta marshaller wraps
372 	 * @closure->marshal and modifies the way it is called in some
373 	 * fashion. The most common use of this facility is for C callbacks.
374 	 * The same marshallers (generated by [glib-genmarshal][glib-genmarshal]),
375 	 * are used everywhere, but the way that we get the callback function
376 	 * differs. In most cases we want to use @closure->callback, but in
377 	 * other cases we want to use some different technique to retrieve the
378 	 * callback function.
379 	 *
380 	 * For example, class closures for signals (see
381 	 * g_signal_type_cclosure_new()) retrieve the callback function from a
382 	 * fixed offset in the class structure.  The meta marshaller retrieves
383 	 * the right callback and passes it to the marshaller as the
384 	 * @marshal_data argument.
385 	 *
386 	 * Params:
387 	 *     marshalData = context-dependent data to pass
388 	 *         to @meta_marshal
389 	 *     metaMarshal = a #GClosureMarshal function
390 	 */
391 	public void setMetaMarshal(void* marshalData, GClosureMarshal metaMarshal)
392 	{
393 		g_closure_set_meta_marshal(gClosure, marshalData, metaMarshal);
394 	}
395 
396 	/**
397 	 * Takes over the initial ownership of a closure.  Each closure is
398 	 * initially created in a "floating" state, which means that the initial
399 	 * reference count is not owned by any caller. g_closure_sink() checks
400 	 * to see if the object is still floating, and if so, unsets the
401 	 * floating state and decreases the reference count. If the closure
402 	 * is not floating, g_closure_sink() does nothing. The reason for the
403 	 * existence of the floating state is to prevent cumbersome code
404 	 * sequences like:
405 	 * |[<!-- language="C" -->
406 	 * closure = g_cclosure_new (cb_func, cb_data);
407 	 * g_source_set_closure (source, closure);
408 	 * g_closure_unref (closure); // GObject doesn't really need this
409 	 * ]|
410 	 * Because g_source_set_closure() (and similar functions) take ownership of the
411 	 * initial reference count, if it is unowned, we instead can write:
412 	 * |[<!-- language="C" -->
413 	 * g_source_set_closure (source, g_cclosure_new (cb_func, cb_data));
414 	 * ]|
415 	 *
416 	 * Generally, this function is used together with g_closure_ref(). Ane example
417 	 * of storing a closure for later notification looks like:
418 	 * |[<!-- language="C" -->
419 	 * static GClosure *notify_closure = NULL;
420 	 * void
421 	 * foo_notify_set_closure (GClosure *closure)
422 	 * {
423 	 * if (notify_closure)
424 	 * g_closure_unref (notify_closure);
425 	 * notify_closure = closure;
426 	 * if (notify_closure)
427 	 * {
428 	 * g_closure_ref (notify_closure);
429 	 * g_closure_sink (notify_closure);
430 	 * }
431 	 * }
432 	 * ]|
433 	 *
434 	 * Because g_closure_sink() may decrement the reference count of a closure
435 	 * (if it hasn't been called on @closure yet) just like g_closure_unref(),
436 	 * g_closure_ref() should be called prior to this function.
437 	 */
438 	public void sink()
439 	{
440 		g_closure_sink(gClosure);
441 	}
442 
443 	/**
444 	 * Decrements the reference count of a closure after it was previously
445 	 * incremented by the same caller. If no other callers are using the
446 	 * closure, then the closure will be destroyed and freed.
447 	 */
448 	public void unref()
449 	{
450 		g_closure_unref(gClosure);
451 	}
452 
453 	/**
454 	 * Set the callback for a source as a #GClosure.
455 	 *
456 	 * If the source is not one of the standard GLib types, the @closure_callback
457 	 * and @closure_marshal fields of the #GSourceFuncs structure must have been
458 	 * filled in with pointers to appropriate functions.
459 	 *
460 	 * Params:
461 	 *     source = the source
462 	 *     closure = a #GClosure
463 	 */
464 	public static void sourceSetClosure(Source source, Closure closure)
465 	{
466 		g_source_set_closure((source is null) ? null : source.getSourceStruct(), (closure is null) ? null : closure.getClosureStruct());
467 	}
468 
469 	/**
470 	 * Sets a dummy callback for @source. The callback will do nothing, and
471 	 * if the source expects a #gboolean return value, it will return %TRUE.
472 	 * (If the source expects any other type of return value, it will return
473 	 * a 0/%NULL value; whatever g_value_init() initializes a #GValue to for
474 	 * that type.)
475 	 *
476 	 * If the source is not one of the standard GLib types, the
477 	 * @closure_callback and @closure_marshal fields of the #GSourceFuncs
478 	 * structure must have been filled in with pointers to appropriate
479 	 * functions.
480 	 *
481 	 * Params:
482 	 *     source = the source
483 	 */
484 	public static void sourceSetDummyCallback(Source source)
485 	{
486 		g_source_set_dummy_callback((source is null) ? null : source.getSourceStruct());
487 	}
488 }