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 gio.Task;
26 
27 private import gio.AsyncResultIF;
28 private import gio.AsyncResultT;
29 private import gio.Cancellable;
30 private import glib.ConstructionException;
31 private import glib.ErrorG;
32 private import glib.GException;
33 private import glib.MainContext;
34 private import glib.Source;
35 private import glib.Str;
36 private import gobject.ObjectG;
37 private import gtkc.gio;
38 public  import gtkc.giotypes;
39 
40 
41 /**
42  * A #GTask represents and manages a cancellable "task".
43  * 
44  * ## Asynchronous operations
45  * 
46  * The most common usage of #GTask is as a #GAsyncResult, to
47  * manage data during an asynchronous operation. You call
48  * g_task_new() in the "start" method, followed by
49  * g_task_set_task_data() and the like if you need to keep some
50  * additional data associated with the task, and then pass the
51  * task object around through your asynchronous operation.
52  * Eventually, you will call a method such as
53  * g_task_return_pointer() or g_task_return_error(), which will
54  * save the value you give it and then invoke the task's callback
55  * function (waiting until the next iteration of the main
56  * loop first, if necessary). The caller will pass the #GTask back
57  * to the operation's finish function (as a #GAsyncResult), and
58  * you can use g_task_propagate_pointer() or the like to extract
59  * the return value.
60  * 
61  * Here is an example for using GTask as a GAsyncResult:
62  * |[<!-- language="C" -->
63  * typedef struct {
64  * CakeFrostingType frosting;
65  * char *message;
66  * } DecorationData;
67  * 
68  * static void
69  * decoration_data_free (DecorationData *decoration)
70  * {
71  * g_free (decoration->message);
72  * g_slice_free (DecorationData, decoration);
73  * }
74  * 
75  * static void
76  * baked_cb (Cake     *cake,
77  * gpointer  user_data)
78  * {
79  * GTask *task = user_data;
80  * DecorationData *decoration = g_task_get_task_data (task);
81  * GError *error = NULL;
82  * 
83  * if (cake == NULL)
84  * {
85  * g_task_return_new_error (task, BAKER_ERROR, BAKER_ERROR_NO_FLOUR,
86  * "Go to the supermarket");
87  * g_object_unref (task);
88  * return;
89  * }
90  * 
91  * if (!cake_decorate (cake, decoration->frosting, decoration->message, &error))
92  * {
93  * g_object_unref (cake);
94  * // g_task_return_error() takes ownership of error
95  * g_task_return_error (task, error);
96  * g_object_unref (task);
97  * return;
98  * }
99  * 
100  * g_task_return_pointer (task, cake, g_object_unref);
101  * g_object_unref (task);
102  * }
103  * 
104  * void
105  * baker_bake_cake_async (Baker               *self,
106  * guint                radius,
107  * CakeFlavor           flavor,
108  * CakeFrostingType     frosting,
109  * const char          *message,
110  * GCancellable        *cancellable,
111  * GAsyncReadyCallback  callback,
112  * gpointer             user_data)
113  * {
114  * GTask *task;
115  * DecorationData *decoration;
116  * Cake  *cake;
117  * 
118  * task = g_task_new (self, cancellable, callback, user_data);
119  * if (radius < 3)
120  * {
121  * g_task_return_new_error (task, BAKER_ERROR, BAKER_ERROR_TOO_SMALL,
122  * "%ucm radius cakes are silly",
123  * radius);
124  * g_object_unref (task);
125  * return;
126  * }
127  * 
128  * cake = _baker_get_cached_cake (self, radius, flavor, frosting, message);
129  * if (cake != NULL)
130  * {
131  * // _baker_get_cached_cake() returns a reffed cake
132  * g_task_return_pointer (task, cake, g_object_unref);
133  * g_object_unref (task);
134  * return;
135  * }
136  * 
137  * decoration = g_slice_new (DecorationData);
138  * decoration->frosting = frosting;
139  * decoration->message = g_strdup (message);
140  * g_task_set_task_data (task, decoration, (GDestroyNotify) decoration_data_free);
141  * 
142  * _baker_begin_cake (self, radius, flavor, cancellable, baked_cb, task);
143  * }
144  * 
145  * Cake *
146  * baker_bake_cake_finish (Baker         *self,
147  * GAsyncResult  *result,
148  * GError       **error)
149  * {
150  * g_return_val_if_fail (g_task_is_valid (result, self), NULL);
151  * 
152  * return g_task_propagate_pointer (G_TASK (result), error);
153  * }
154  * ]|
155  * 
156  * ## Chained asynchronous operations
157  * 
158  * #GTask also tries to simplify asynchronous operations that
159  * internally chain together several smaller asynchronous
160  * operations. g_task_get_cancellable(), g_task_get_context(),
161  * and g_task_get_priority() allow you to get back the task's
162  * #GCancellable, #GMainContext, and [I/O priority][io-priority]
163  * when starting a new subtask, so you don't have to keep track
164  * of them yourself. g_task_attach_source() simplifies the case
165  * of waiting for a source to fire (automatically using the correct
166  * #GMainContext and priority).
167  * 
168  * Here is an example for chained asynchronous operations:
169  * |[<!-- language="C" -->
170  * typedef struct {
171  * Cake *cake;
172  * CakeFrostingType frosting;
173  * char *message;
174  * } BakingData;
175  * 
176  * static void
177  * decoration_data_free (BakingData *bd)
178  * {
179  * if (bd->cake)
180  * g_object_unref (bd->cake);
181  * g_free (bd->message);
182  * g_slice_free (BakingData, bd);
183  * }
184  * 
185  * static void
186  * decorated_cb (Cake         *cake,
187  * GAsyncResult *result,
188  * gpointer      user_data)
189  * {
190  * GTask *task = user_data;
191  * GError *error = NULL;
192  * 
193  * if (!cake_decorate_finish (cake, result, &error))
194  * {
195  * g_object_unref (cake);
196  * g_task_return_error (task, error);
197  * g_object_unref (task);
198  * return;
199  * }
200  * 
201  * // baking_data_free() will drop its ref on the cake, so we have to
202  * // take another here to give to the caller.
203  * g_task_return_pointer (task, g_object_ref (cake), g_object_unref);
204  * g_object_unref (task);
205  * }
206  * 
207  * static gboolean
208  * decorator_ready (gpointer user_data)
209  * {
210  * GTask *task = user_data;
211  * BakingData *bd = g_task_get_task_data (task);
212  * 
213  * cake_decorate_async (bd->cake, bd->frosting, bd->message,
214  * g_task_get_cancellable (task),
215  * decorated_cb, task);
216  * 
217  * return G_SOURCE_REMOVE;
218  * }
219  * 
220  * static void
221  * baked_cb (Cake     *cake,
222  * gpointer  user_data)
223  * {
224  * GTask *task = user_data;
225  * BakingData *bd = g_task_get_task_data (task);
226  * GError *error = NULL;
227  * 
228  * if (cake == NULL)
229  * {
230  * g_task_return_new_error (task, BAKER_ERROR, BAKER_ERROR_NO_FLOUR,
231  * "Go to the supermarket");
232  * g_object_unref (task);
233  * return;
234  * }
235  * 
236  * bd->cake = cake;
237  * 
238  * // Bail out now if the user has already cancelled
239  * if (g_task_return_error_if_cancelled (task))
240  * {
241  * g_object_unref (task);
242  * return;
243  * }
244  * 
245  * if (cake_decorator_available (cake))
246  * decorator_ready (task);
247  * else
248  * {
249  * GSource *source;
250  * 
251  * source = cake_decorator_wait_source_new (cake);
252  * // Attach @source to @task's GMainContext and have it call
253  * // decorator_ready() when it is ready.
254  * g_task_attach_source (task, source, decorator_ready);
255  * g_source_unref (source);
256  * }
257  * }
258  * 
259  * void
260  * baker_bake_cake_async (Baker               *self,
261  * guint                radius,
262  * CakeFlavor           flavor,
263  * CakeFrostingType     frosting,
264  * const char          *message,
265  * gint                 priority,
266  * GCancellable        *cancellable,
267  * GAsyncReadyCallback  callback,
268  * gpointer             user_data)
269  * {
270  * GTask *task;
271  * BakingData *bd;
272  * 
273  * task = g_task_new (self, cancellable, callback, user_data);
274  * g_task_set_priority (task, priority);
275  * 
276  * bd = g_slice_new0 (BakingData);
277  * bd->frosting = frosting;
278  * bd->message = g_strdup (message);
279  * g_task_set_task_data (task, bd, (GDestroyNotify) baking_data_free);
280  * 
281  * _baker_begin_cake (self, radius, flavor, cancellable, baked_cb, task);
282  * }
283  * 
284  * Cake *
285  * baker_bake_cake_finish (Baker         *self,
286  * GAsyncResult  *result,
287  * GError       **error)
288  * {
289  * g_return_val_if_fail (g_task_is_valid (result, self), NULL);
290  * 
291  * return g_task_propagate_pointer (G_TASK (result), error);
292  * }
293  * ]|
294  * 
295  * ## Asynchronous operations from synchronous ones
296  * 
297  * You can use g_task_run_in_thread() to turn a synchronous
298  * operation into an asynchronous one, by running it in a thread
299  * which will then dispatch the result back to the caller's
300  * #GMainContext when it completes.
301  * 
302  * Running a task in a thread:
303  * |[<!-- language="C" -->
304  * typedef struct {
305  * guint radius;
306  * CakeFlavor flavor;
307  * CakeFrostingType frosting;
308  * char *message;
309  * } CakeData;
310  * 
311  * static void
312  * cake_data_free (CakeData *cake_data)
313  * {
314  * g_free (cake_data->message);
315  * g_slice_free (CakeData, cake_data);
316  * }
317  * 
318  * static void
319  * bake_cake_thread (GTask         *task,
320  * gpointer       source_object,
321  * gpointer       task_data,
322  * GCancellable  *cancellable)
323  * {
324  * Baker *self = source_object;
325  * CakeData *cake_data = task_data;
326  * Cake *cake;
327  * GError *error = NULL;
328  * 
329  * cake = bake_cake (baker, cake_data->radius, cake_data->flavor,
330  * cake_data->frosting, cake_data->message,
331  * cancellable, &error);
332  * if (cake)
333  * g_task_return_pointer (task, cake, g_object_unref);
334  * else
335  * g_task_return_error (task, error);
336  * }
337  * 
338  * void
339  * baker_bake_cake_async (Baker               *self,
340  * guint                radius,
341  * CakeFlavor           flavor,
342  * CakeFrostingType     frosting,
343  * const char          *message,
344  * GCancellable        *cancellable,
345  * GAsyncReadyCallback  callback,
346  * gpointer             user_data)
347  * {
348  * CakeData *cake_data;
349  * GTask *task;
350  * 
351  * cake_data = g_slice_new (CakeData);
352  * cake_data->radius = radius;
353  * cake_data->flavor = flavor;
354  * cake_data->frosting = frosting;
355  * cake_data->message = g_strdup (message);
356  * task = g_task_new (self, cancellable, callback, user_data);
357  * g_task_set_task_data (task, cake_data, (GDestroyNotify) cake_data_free);
358  * g_task_run_in_thread (task, bake_cake_thread);
359  * g_object_unref (task);
360  * }
361  * 
362  * Cake *
363  * baker_bake_cake_finish (Baker         *self,
364  * GAsyncResult  *result,
365  * GError       **error)
366  * {
367  * g_return_val_if_fail (g_task_is_valid (result, self), NULL);
368  * 
369  * return g_task_propagate_pointer (G_TASK (result), error);
370  * }
371  * ]|
372  * 
373  * ## Adding cancellability to uncancellable tasks
374  * 
375  * Finally, g_task_run_in_thread() and g_task_run_in_thread_sync()
376  * can be used to turn an uncancellable operation into a
377  * cancellable one. If you call g_task_set_return_on_cancel(),
378  * passing %TRUE, then if the task's #GCancellable is cancelled,
379  * it will return control back to the caller immediately, while
380  * allowing the task thread to continue running in the background
381  * (and simply discarding its result when it finally does finish).
382  * Provided that the task thread is careful about how it uses
383  * locks and other externally-visible resources, this allows you
384  * to make "GLib-friendly" asynchronous and cancellable
385  * synchronous variants of blocking APIs.
386  * 
387  * Cancelling a task:
388  * |[<!-- language="C" -->
389  * static void
390  * bake_cake_thread (GTask         *task,
391  * gpointer       source_object,
392  * gpointer       task_data,
393  * GCancellable  *cancellable)
394  * {
395  * Baker *self = source_object;
396  * CakeData *cake_data = task_data;
397  * Cake *cake;
398  * GError *error = NULL;
399  * 
400  * cake = bake_cake (baker, cake_data->radius, cake_data->flavor,
401  * cake_data->frosting, cake_data->message,
402  * &error);
403  * if (error)
404  * {
405  * g_task_return_error (task, error);
406  * return;
407  * }
408  * 
409  * // If the task has already been cancelled, then we don't want to add
410  * // the cake to the cake cache. Likewise, we don't  want to have the
411  * // task get cancelled in the middle of updating the cache.
412  * // g_task_set_return_on_cancel() will return %TRUE here if it managed
413  * // to disable return-on-cancel, or %FALSE if the task was cancelled
414  * // before it could.
415  * if (g_task_set_return_on_cancel (task, FALSE))
416  * {
417  * // If the caller cancels at this point, their
418  * // GAsyncReadyCallback won't be invoked until we return,
419  * // so we don't have to worry that this code will run at
420  * // the same time as that code does. But if there were
421  * // other functions that might look at the cake cache,
422  * // then we'd probably need a GMutex here as well.
423  * baker_add_cake_to_cache (baker, cake);
424  * g_task_return_pointer (task, cake, g_object_unref);
425  * }
426  * }
427  * 
428  * void
429  * baker_bake_cake_async (Baker               *self,
430  * guint                radius,
431  * CakeFlavor           flavor,
432  * CakeFrostingType     frosting,
433  * const char          *message,
434  * GCancellable        *cancellable,
435  * GAsyncReadyCallback  callback,
436  * gpointer             user_data)
437  * {
438  * CakeData *cake_data;
439  * GTask *task;
440  * 
441  * cake_data = g_slice_new (CakeData);
442  * 
443  * ...
444  * 
445  * task = g_task_new (self, cancellable, callback, user_data);
446  * g_task_set_task_data (task, cake_data, (GDestroyNotify) cake_data_free);
447  * g_task_set_return_on_cancel (task, TRUE);
448  * g_task_run_in_thread (task, bake_cake_thread);
449  * }
450  * 
451  * Cake *
452  * baker_bake_cake_sync (Baker               *self,
453  * guint                radius,
454  * CakeFlavor           flavor,
455  * CakeFrostingType     frosting,
456  * const char          *message,
457  * GCancellable        *cancellable,
458  * GError             **error)
459  * {
460  * CakeData *cake_data;
461  * GTask *task;
462  * Cake *cake;
463  * 
464  * cake_data = g_slice_new (CakeData);
465  * 
466  * ...
467  * 
468  * task = g_task_new (self, cancellable, NULL, NULL);
469  * g_task_set_task_data (task, cake_data, (GDestroyNotify) cake_data_free);
470  * g_task_set_return_on_cancel (task, TRUE);
471  * g_task_run_in_thread_sync (task, bake_cake_thread);
472  * 
473  * cake = g_task_propagate_pointer (task, error);
474  * g_object_unref (task);
475  * return cake;
476  * }
477  * ]|
478  * 
479  * ## Porting from GSimpleAsyncResult
480  * 
481  * #GTask's API attempts to be simpler than #GSimpleAsyncResult's
482  * in several ways:
483  * - You can save task-specific data with g_task_set_task_data(), and
484  * retrieve it later with g_task_get_task_data(). This replaces the
485  * abuse of g_simple_async_result_set_op_res_gpointer() for the same
486  * purpose with #GSimpleAsyncResult.
487  * - In addition to the task data, #GTask also keeps track of the
488  * [priority][io-priority], #GCancellable, and
489  * #GMainContext associated with the task, so tasks that consist of
490  * a chain of simpler asynchronous operations will have easy access
491  * to those values when starting each sub-task.
492  * - g_task_return_error_if_cancelled() provides simplified
493  * handling for cancellation. In addition, cancellation
494  * overrides any other #GTask return value by default, like
495  * #GSimpleAsyncResult does when
496  * g_simple_async_result_set_check_cancellable() is called.
497  * (You can use g_task_set_check_cancellable() to turn off that
498  * behavior.) On the other hand, g_task_run_in_thread()
499  * guarantees that it will always run your
500  * `task_func`, even if the task's #GCancellable
501  * is already cancelled before the task gets a chance to run;
502  * you can start your `task_func` with a
503  * g_task_return_error_if_cancelled() check if you need the
504  * old behavior.
505  * - The "return" methods (eg, g_task_return_pointer())
506  * automatically cause the task to be "completed" as well, and
507  * there is no need to worry about the "complete" vs "complete
508  * in idle" distinction. (#GTask automatically figures out
509  * whether the task's callback can be invoked directly, or
510  * if it needs to be sent to another #GMainContext, or delayed
511  * until the next iteration of the current #GMainContext.)
512  * - The "finish" functions for #GTask-based operations are generally
513  * much simpler than #GSimpleAsyncResult ones, normally consisting
514  * of only a single call to g_task_propagate_pointer() or the like.
515  * Since g_task_propagate_pointer() "steals" the return value from
516  * the #GTask, it is not necessary to juggle pointers around to
517  * prevent it from being freed twice.
518  * - With #GSimpleAsyncResult, it was common to call
519  * g_simple_async_result_propagate_error() from the
520  * `_finish()` wrapper function, and have
521  * virtual method implementations only deal with successful
522  * returns. This behavior is deprecated, because it makes it
523  * difficult for a subclass to chain to a parent class's async
524  * methods. Instead, the wrapper function should just be a
525  * simple wrapper, and the virtual method should call an
526  * appropriate `g_task_propagate_` function.
527  * Note that wrapper methods can now use
528  * g_async_result_legacy_propagate_error() to do old-style
529  * #GSimpleAsyncResult error-returning behavior, and
530  * g_async_result_is_tagged() to check if a result is tagged as
531  * having come from the `_async()` wrapper
532  * function (for "short-circuit" results, such as when passing
533  * 0 to g_input_stream_read_async()).
534  */
535 public class Task : ObjectG, AsyncResultIF
536 {
537 	/** the main Gtk struct */
538 	protected GTask* gTask;
539 
540 	/** Get the main Gtk struct */
541 	public GTask* getTaskStruct(bool transferOwnership = false)
542 	{
543 		if (transferOwnership)
544 			ownedRef = false;
545 		return gTask;
546 	}
547 
548 	/** the main Gtk struct as a void* */
549 	protected override void* getStruct()
550 	{
551 		return cast(void*)gTask;
552 	}
553 
554 	protected override void setStruct(GObject* obj)
555 	{
556 		gTask = cast(GTask*)obj;
557 		super.setStruct(obj);
558 	}
559 
560 	/**
561 	 * Sets our main struct and passes it to the parent class.
562 	 */
563 	public this (GTask* gTask, bool ownedRef = false)
564 	{
565 		this.gTask = gTask;
566 		super(cast(GObject*)gTask, ownedRef);
567 	}
568 
569 	// add the AsyncResult capabilities
570 	mixin AsyncResultT!(GTask);
571 
572 
573 	/** */
574 	public static GType getType()
575 	{
576 		return g_task_get_type();
577 	}
578 
579 	/**
580 	 * Creates a #GTask acting on @source_object, which will eventually be
581 	 * used to invoke @callback in the current
582 	 * [thread-default main context][g-main-context-push-thread-default].
583 	 *
584 	 * Call this in the "start" method of your asynchronous method, and
585 	 * pass the #GTask around throughout the asynchronous operation. You
586 	 * can use g_task_set_task_data() to attach task-specific data to the
587 	 * object, which you can retrieve later via g_task_get_task_data().
588 	 *
589 	 * By default, if @cancellable is cancelled, then the return value of
590 	 * the task will always be %G_IO_ERROR_CANCELLED, even if the task had
591 	 * already completed before the cancellation. This allows for
592 	 * simplified handling in cases where cancellation may imply that
593 	 * other objects that the task depends on have been destroyed. If you
594 	 * do not want this behavior, you can use
595 	 * g_task_set_check_cancellable() to change it.
596 	 *
597 	 * Params:
598 	 *     sourceObject = the #GObject that owns
599 	 *         this task, or %NULL.
600 	 *     cancellable = optional #GCancellable object, %NULL to ignore.
601 	 *     callback = a #GAsyncReadyCallback.
602 	 *     callbackData = user data passed to @callback.
603 	 *
604 	 * Returns: a #GTask.
605 	 *
606 	 * Since: 2.36
607 	 *
608 	 * Throws: ConstructionException GTK+ fails to create the object.
609 	 */
610 	public this(ObjectG sourceObject, Cancellable cancellable, GAsyncReadyCallback callback, void* callbackData)
611 	{
612 		auto p = g_task_new((sourceObject is null) ? null : sourceObject.getObjectGStruct(), (cancellable is null) ? null : cancellable.getCancellableStruct(), callback, callbackData);
613 		
614 		if(p is null)
615 		{
616 			throw new ConstructionException("null returned by new");
617 		}
618 		
619 		this(cast(GTask*) p, true);
620 	}
621 
622 	/**
623 	 * Checks that @result is a #GTask, and that @source_object is its
624 	 * source object (or that @source_object is %NULL and @result has no
625 	 * source object). This can be used in g_return_if_fail() checks.
626 	 *
627 	 * Params:
628 	 *     result = A #GAsyncResult
629 	 *     sourceObject = the source object
630 	 *         expected to be associated with the task
631 	 *
632 	 * Returns: %TRUE if @result and @source_object are valid, %FALSE
633 	 *     if not
634 	 *
635 	 * Since: 2.36
636 	 */
637 	public static bool isValid(AsyncResultIF result, ObjectG sourceObject)
638 	{
639 		return g_task_is_valid((result is null) ? null : result.getAsyncResultStruct(), (sourceObject is null) ? null : sourceObject.getObjectGStruct()) != 0;
640 	}
641 
642 	/**
643 	 * Creates a #GTask and then immediately calls g_task_return_error()
644 	 * on it. Use this in the wrapper function of an asynchronous method
645 	 * when you want to avoid even calling the virtual method. You can
646 	 * then use g_async_result_is_tagged() in the finish method wrapper to
647 	 * check if the result there is tagged as having been created by the
648 	 * wrapper method, and deal with it appropriately if so.
649 	 *
650 	 * See also g_task_report_new_error().
651 	 *
652 	 * Params:
653 	 *     sourceObject = the #GObject that owns
654 	 *         this task, or %NULL.
655 	 *     callback = a #GAsyncReadyCallback.
656 	 *     callbackData = user data passed to @callback.
657 	 *     sourceTag = an opaque pointer indicating the source of this task
658 	 *     error = error to report
659 	 *
660 	 * Since: 2.36
661 	 */
662 	public static void reportError(ObjectG sourceObject, GAsyncReadyCallback callback, void* callbackData, void* sourceTag, ErrorG error)
663 	{
664 		g_task_report_error((sourceObject is null) ? null : sourceObject.getObjectGStruct(), callback, callbackData, sourceTag, (error is null) ? null : error.getErrorGStruct(true));
665 	}
666 
667 	/**
668 	 * A utility function for dealing with async operations where you need
669 	 * to wait for a #GSource to trigger. Attaches @source to @task's
670 	 * #GMainContext with @task's [priority][io-priority], and sets @source's
671 	 * callback to @callback, with @task as the callback's `user_data`.
672 	 *
673 	 * This takes a reference on @task until @source is destroyed.
674 	 *
675 	 * Params:
676 	 *     source = the source to attach
677 	 *     callback = the callback to invoke when @source triggers
678 	 *
679 	 * Since: 2.36
680 	 */
681 	public void attachSource(Source source, GSourceFunc callback)
682 	{
683 		g_task_attach_source(gTask, (source is null) ? null : source.getSourceStruct(), callback);
684 	}
685 
686 	/**
687 	 * Gets @task's #GCancellable
688 	 *
689 	 * Returns: @task's #GCancellable
690 	 *
691 	 * Since: 2.36
692 	 */
693 	public Cancellable getCancellable()
694 	{
695 		auto p = g_task_get_cancellable(gTask);
696 		
697 		if(p is null)
698 		{
699 			return null;
700 		}
701 		
702 		return ObjectG.getDObject!(Cancellable)(cast(GCancellable*) p);
703 	}
704 
705 	/**
706 	 * Gets @task's check-cancellable flag. See
707 	 * g_task_set_check_cancellable() for more details.
708 	 *
709 	 * Since: 2.36
710 	 */
711 	public bool getCheckCancellable()
712 	{
713 		return g_task_get_check_cancellable(gTask) != 0;
714 	}
715 
716 	/**
717 	 * Gets the value of #GTask:completed. This changes from %FALSE to %TRUE after
718 	 * the task’s callback is invoked, and will return %FALSE if called from inside
719 	 * the callback.
720 	 *
721 	 * Returns: %TRUE if the task has completed, %FALSE otherwise.
722 	 *
723 	 * Since: 2.44
724 	 */
725 	public bool getCompleted()
726 	{
727 		return g_task_get_completed(gTask) != 0;
728 	}
729 
730 	/**
731 	 * Gets the #GMainContext that @task will return its result in (that
732 	 * is, the context that was the
733 	 * [thread-default main context][g-main-context-push-thread-default]
734 	 * at the point when @task was created).
735 	 *
736 	 * This will always return a non-%NULL value, even if the task's
737 	 * context is the default #GMainContext.
738 	 *
739 	 * Returns: @task's #GMainContext
740 	 *
741 	 * Since: 2.36
742 	 */
743 	public MainContext getContext()
744 	{
745 		auto p = g_task_get_context(gTask);
746 		
747 		if(p is null)
748 		{
749 			return null;
750 		}
751 		
752 		return new MainContext(cast(GMainContext*) p);
753 	}
754 
755 	/**
756 	 * Gets @task's priority
757 	 *
758 	 * Returns: @task's priority
759 	 *
760 	 * Since: 2.36
761 	 */
762 	public int getPriority()
763 	{
764 		return g_task_get_priority(gTask);
765 	}
766 
767 	/**
768 	 * Gets @task's return-on-cancel flag. See
769 	 * g_task_set_return_on_cancel() for more details.
770 	 *
771 	 * Since: 2.36
772 	 */
773 	public bool getReturnOnCancel()
774 	{
775 		return g_task_get_return_on_cancel(gTask) != 0;
776 	}
777 
778 	/**
779 	 * Gets the source object from @task. Like
780 	 * g_async_result_get_source_object(), but does not ref the object.
781 	 *
782 	 * Returns: @task's source object, or %NULL
783 	 *
784 	 * Since: 2.36
785 	 */
786 	public ObjectG getSourceObject()
787 	{
788 		auto p = g_task_get_source_object(gTask);
789 		
790 		if(p is null)
791 		{
792 			return null;
793 		}
794 		
795 		return ObjectG.getDObject!(ObjectG)(cast(GObject*) p);
796 	}
797 
798 	/**
799 	 * Gets @task's source tag. See g_task_set_source_tag().
800 	 *
801 	 * Returns: @task's source tag
802 	 *
803 	 * Since: 2.36
804 	 */
805 	public void* getSourceTag()
806 	{
807 		return g_task_get_source_tag(gTask);
808 	}
809 
810 	/**
811 	 * Gets @task's `task_data`.
812 	 *
813 	 * Returns: @task's `task_data`.
814 	 *
815 	 * Since: 2.36
816 	 */
817 	public void* getTaskData()
818 	{
819 		return g_task_get_task_data(gTask);
820 	}
821 
822 	/**
823 	 * Tests if @task resulted in an error.
824 	 *
825 	 * Returns: %TRUE if the task resulted in an error, %FALSE otherwise.
826 	 *
827 	 * Since: 2.36
828 	 */
829 	public bool hadError()
830 	{
831 		return g_task_had_error(gTask) != 0;
832 	}
833 
834 	/**
835 	 * Gets the result of @task as a #gboolean.
836 	 *
837 	 * If the task resulted in an error, or was cancelled, then this will
838 	 * instead return %FALSE and set @error.
839 	 *
840 	 * Since this method transfers ownership of the return value (or
841 	 * error) to the caller, you may only call it once.
842 	 *
843 	 * Returns: the task result, or %FALSE on error
844 	 *
845 	 * Since: 2.36
846 	 *
847 	 * Throws: GException on failure.
848 	 */
849 	public bool propagateBoolean()
850 	{
851 		GError* err = null;
852 		
853 		auto p = g_task_propagate_boolean(gTask, &err) != 0;
854 		
855 		if (err !is null)
856 		{
857 			throw new GException( new ErrorG(err) );
858 		}
859 		
860 		return p;
861 	}
862 
863 	/**
864 	 * Gets the result of @task as an integer (#gssize).
865 	 *
866 	 * If the task resulted in an error, or was cancelled, then this will
867 	 * instead return -1 and set @error.
868 	 *
869 	 * Since this method transfers ownership of the return value (or
870 	 * error) to the caller, you may only call it once.
871 	 *
872 	 * Returns: the task result, or -1 on error
873 	 *
874 	 * Since: 2.36
875 	 *
876 	 * Throws: GException on failure.
877 	 */
878 	public ptrdiff_t propagateInt()
879 	{
880 		GError* err = null;
881 		
882 		auto p = g_task_propagate_int(gTask, &err);
883 		
884 		if (err !is null)
885 		{
886 			throw new GException( new ErrorG(err) );
887 		}
888 		
889 		return p;
890 	}
891 
892 	/**
893 	 * Gets the result of @task as a pointer, and transfers ownership
894 	 * of that value to the caller.
895 	 *
896 	 * If the task resulted in an error, or was cancelled, then this will
897 	 * instead return %NULL and set @error.
898 	 *
899 	 * Since this method transfers ownership of the return value (or
900 	 * error) to the caller, you may only call it once.
901 	 *
902 	 * Returns: the task result, or %NULL on error
903 	 *
904 	 * Since: 2.36
905 	 *
906 	 * Throws: GException on failure.
907 	 */
908 	public void* propagatePointer()
909 	{
910 		GError* err = null;
911 		
912 		auto p = g_task_propagate_pointer(gTask, &err);
913 		
914 		if (err !is null)
915 		{
916 			throw new GException( new ErrorG(err) );
917 		}
918 		
919 		return p;
920 	}
921 
922 	/**
923 	 * Sets @task's result to @result and completes the task (see
924 	 * g_task_return_pointer() for more discussion of exactly what this
925 	 * means).
926 	 *
927 	 * Params:
928 	 *     result = the #gboolean result of a task function.
929 	 *
930 	 * Since: 2.36
931 	 */
932 	public void returnBoolean(bool result)
933 	{
934 		g_task_return_boolean(gTask, result);
935 	}
936 
937 	/**
938 	 * Sets @task's result to @error (which @task assumes ownership of)
939 	 * and completes the task (see g_task_return_pointer() for more
940 	 * discussion of exactly what this means).
941 	 *
942 	 * Note that since the task takes ownership of @error, and since the
943 	 * task may be completed before returning from g_task_return_error(),
944 	 * you cannot assume that @error is still valid after calling this.
945 	 * Call g_error_copy() on the error if you need to keep a local copy
946 	 * as well.
947 	 *
948 	 * See also g_task_return_new_error().
949 	 *
950 	 * Params:
951 	 *     error = the #GError result of a task function.
952 	 *
953 	 * Since: 2.36
954 	 */
955 	public void returnError(ErrorG error)
956 	{
957 		g_task_return_error(gTask, (error is null) ? null : error.getErrorGStruct(true));
958 	}
959 
960 	/**
961 	 * Checks if @task's #GCancellable has been cancelled, and if so, sets
962 	 * @task's error accordingly and completes the task (see
963 	 * g_task_return_pointer() for more discussion of exactly what this
964 	 * means).
965 	 *
966 	 * Returns: %TRUE if @task has been cancelled, %FALSE if not
967 	 *
968 	 * Since: 2.36
969 	 */
970 	public bool returnErrorIfCancelled()
971 	{
972 		return g_task_return_error_if_cancelled(gTask) != 0;
973 	}
974 
975 	/**
976 	 * Sets @task's result to @result and completes the task (see
977 	 * g_task_return_pointer() for more discussion of exactly what this
978 	 * means).
979 	 *
980 	 * Params:
981 	 *     result = the integer (#gssize) result of a task function.
982 	 *
983 	 * Since: 2.36
984 	 */
985 	public void returnInt(ptrdiff_t result)
986 	{
987 		g_task_return_int(gTask, result);
988 	}
989 
990 	/**
991 	 * Sets @task's result to @result and completes the task. If @result
992 	 * is not %NULL, then @result_destroy will be used to free @result if
993 	 * the caller does not take ownership of it with
994 	 * g_task_propagate_pointer().
995 	 *
996 	 * "Completes the task" means that for an ordinary asynchronous task
997 	 * it will either invoke the task's callback, or else queue that
998 	 * callback to be invoked in the proper #GMainContext, or in the next
999 	 * iteration of the current #GMainContext. For a task run via
1000 	 * g_task_run_in_thread() or g_task_run_in_thread_sync(), calling this
1001 	 * method will save @result to be returned to the caller later, but
1002 	 * the task will not actually be completed until the #GTaskThreadFunc
1003 	 * exits.
1004 	 *
1005 	 * Note that since the task may be completed before returning from
1006 	 * g_task_return_pointer(), you cannot assume that @result is still
1007 	 * valid after calling this, unless you are still holding another
1008 	 * reference on it.
1009 	 *
1010 	 * Params:
1011 	 *     result = the pointer result of a task
1012 	 *         function
1013 	 *     resultDestroy = a #GDestroyNotify function.
1014 	 *
1015 	 * Since: 2.36
1016 	 */
1017 	public void returnPointer(void* result, GDestroyNotify resultDestroy)
1018 	{
1019 		g_task_return_pointer(gTask, result, resultDestroy);
1020 	}
1021 
1022 	/**
1023 	 * Runs @task_func in another thread. When @task_func returns, @task's
1024 	 * #GAsyncReadyCallback will be invoked in @task's #GMainContext.
1025 	 *
1026 	 * This takes a ref on @task until the task completes.
1027 	 *
1028 	 * See #GTaskThreadFunc for more details about how @task_func is handled.
1029 	 *
1030 	 * Although GLib currently rate-limits the tasks queued via
1031 	 * g_task_run_in_thread(), you should not assume that it will always
1032 	 * do this. If you have a very large number of tasks to run, but don't
1033 	 * want them to all run at once, you should only queue a limited
1034 	 * number of them at a time.
1035 	 *
1036 	 * Params:
1037 	 *     taskFunc = a #GTaskThreadFunc
1038 	 *
1039 	 * Since: 2.36
1040 	 */
1041 	public void runInThread(GTaskThreadFunc taskFunc)
1042 	{
1043 		g_task_run_in_thread(gTask, taskFunc);
1044 	}
1045 
1046 	/**
1047 	 * Runs @task_func in another thread, and waits for it to return or be
1048 	 * cancelled. You can use g_task_propagate_pointer(), etc, afterward
1049 	 * to get the result of @task_func.
1050 	 *
1051 	 * See #GTaskThreadFunc for more details about how @task_func is handled.
1052 	 *
1053 	 * Normally this is used with tasks created with a %NULL
1054 	 * `callback`, but note that even if the task does
1055 	 * have a callback, it will not be invoked when @task_func returns.
1056 	 * #GTask:completed will be set to %TRUE just before this function returns.
1057 	 *
1058 	 * Although GLib currently rate-limits the tasks queued via
1059 	 * g_task_run_in_thread_sync(), you should not assume that it will
1060 	 * always do this. If you have a very large number of tasks to run,
1061 	 * but don't want them to all run at once, you should only queue a
1062 	 * limited number of them at a time.
1063 	 *
1064 	 * Params:
1065 	 *     taskFunc = a #GTaskThreadFunc
1066 	 *
1067 	 * Since: 2.36
1068 	 */
1069 	public void runInThreadSync(GTaskThreadFunc taskFunc)
1070 	{
1071 		g_task_run_in_thread_sync(gTask, taskFunc);
1072 	}
1073 
1074 	/**
1075 	 * Sets or clears @task's check-cancellable flag. If this is %TRUE
1076 	 * (the default), then g_task_propagate_pointer(), etc, and
1077 	 * g_task_had_error() will check the task's #GCancellable first, and
1078 	 * if it has been cancelled, then they will consider the task to have
1079 	 * returned an "Operation was cancelled" error
1080 	 * (%G_IO_ERROR_CANCELLED), regardless of any other error or return
1081 	 * value the task may have had.
1082 	 *
1083 	 * If @check_cancellable is %FALSE, then the #GTask will not check the
1084 	 * cancellable itself, and it is up to @task's owner to do this (eg,
1085 	 * via g_task_return_error_if_cancelled()).
1086 	 *
1087 	 * If you are using g_task_set_return_on_cancel() as well, then
1088 	 * you must leave check-cancellable set %TRUE.
1089 	 *
1090 	 * Params:
1091 	 *     checkCancellable = whether #GTask will check the state of
1092 	 *         its #GCancellable for you.
1093 	 *
1094 	 * Since: 2.36
1095 	 */
1096 	public void setCheckCancellable(bool checkCancellable)
1097 	{
1098 		g_task_set_check_cancellable(gTask, checkCancellable);
1099 	}
1100 
1101 	/**
1102 	 * Sets @task's priority. If you do not call this, it will default to
1103 	 * %G_PRIORITY_DEFAULT.
1104 	 *
1105 	 * This will affect the priority of #GSources created with
1106 	 * g_task_attach_source() and the scheduling of tasks run in threads,
1107 	 * and can also be explicitly retrieved later via
1108 	 * g_task_get_priority().
1109 	 *
1110 	 * Params:
1111 	 *     priority = the [priority][io-priority] of the request
1112 	 *
1113 	 * Since: 2.36
1114 	 */
1115 	public void setPriority(int priority)
1116 	{
1117 		g_task_set_priority(gTask, priority);
1118 	}
1119 
1120 	/**
1121 	 * Sets or clears @task's return-on-cancel flag. This is only
1122 	 * meaningful for tasks run via g_task_run_in_thread() or
1123 	 * g_task_run_in_thread_sync().
1124 	 *
1125 	 * If @return_on_cancel is %TRUE, then cancelling @task's
1126 	 * #GCancellable will immediately cause it to return, as though the
1127 	 * task's #GTaskThreadFunc had called
1128 	 * g_task_return_error_if_cancelled() and then returned.
1129 	 *
1130 	 * This allows you to create a cancellable wrapper around an
1131 	 * uninterruptable function. The #GTaskThreadFunc just needs to be
1132 	 * careful that it does not modify any externally-visible state after
1133 	 * it has been cancelled. To do that, the thread should call
1134 	 * g_task_set_return_on_cancel() again to (atomically) set
1135 	 * return-on-cancel %FALSE before making externally-visible changes;
1136 	 * if the task gets cancelled before the return-on-cancel flag could
1137 	 * be changed, g_task_set_return_on_cancel() will indicate this by
1138 	 * returning %FALSE.
1139 	 *
1140 	 * You can disable and re-enable this flag multiple times if you wish.
1141 	 * If the task's #GCancellable is cancelled while return-on-cancel is
1142 	 * %FALSE, then calling g_task_set_return_on_cancel() to set it %TRUE
1143 	 * again will cause the task to be cancelled at that point.
1144 	 *
1145 	 * If the task's #GCancellable is already cancelled before you call
1146 	 * g_task_run_in_thread()/g_task_run_in_thread_sync(), then the
1147 	 * #GTaskThreadFunc will still be run (for consistency), but the task
1148 	 * will also be completed right away.
1149 	 *
1150 	 * Params:
1151 	 *     returnOnCancel = whether the task returns automatically when
1152 	 *         it is cancelled.
1153 	 *
1154 	 * Returns: %TRUE if @task's return-on-cancel flag was changed to
1155 	 *     match @return_on_cancel. %FALSE if @task has already been
1156 	 *     cancelled.
1157 	 *
1158 	 * Since: 2.36
1159 	 */
1160 	public bool setReturnOnCancel(bool returnOnCancel)
1161 	{
1162 		return g_task_set_return_on_cancel(gTask, returnOnCancel) != 0;
1163 	}
1164 
1165 	/**
1166 	 * Sets @task's source tag. You can use this to tag a task return
1167 	 * value with a particular pointer (usually a pointer to the function
1168 	 * doing the tagging) and then later check it using
1169 	 * g_task_get_source_tag() (or g_async_result_is_tagged()) in the
1170 	 * task's "finish" function, to figure out if the response came from a
1171 	 * particular place.
1172 	 *
1173 	 * Params:
1174 	 *     sourceTag = an opaque pointer indicating the source of this task
1175 	 *
1176 	 * Since: 2.36
1177 	 */
1178 	public void setSourceTag(void* sourceTag)
1179 	{
1180 		g_task_set_source_tag(gTask, sourceTag);
1181 	}
1182 
1183 	/**
1184 	 * Sets @task's task data (freeing the existing task data, if any).
1185 	 *
1186 	 * Params:
1187 	 *     taskData = task-specific data
1188 	 *     taskDataDestroy = #GDestroyNotify for @task_data
1189 	 *
1190 	 * Since: 2.36
1191 	 */
1192 	public void setTaskData(void* taskData, GDestroyNotify taskDataDestroy)
1193 	{
1194 		g_task_set_task_data(gTask, taskData, taskDataDestroy);
1195 	}
1196 }