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1846 lines
55 KiB
C
1846 lines
55 KiB
C
/* GIO - GLib Input, Output and Streaming Library
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*
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* Copyright 2011 Red Hat, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General
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* Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "config.h"
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#include "gtask.h"
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#include "gasyncresult.h"
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#include "gcancellable.h"
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/**
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* SECTION:gtask
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* @short_description: Cancellable synchronous or asynchronous task
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* and result
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* @include: gio/gio.h
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* @see_also: #GAsyncResult
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*
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* <para>
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* A #GTask represents and manages a cancellable "task".
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* </para>
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* <refsect2>
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* <title>Asynchronous operations</title>
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* <para>
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* The most common usage of #GTask is as a #GAsyncResult, to
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* manage data during an asynchronous operation. You call
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* g_task_new() in the "start" method, followed by
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* g_task_set_task_data() and the like if you need to keep some
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* additional data associated with the task, and then pass the
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* task object around through your asynchronous operation.
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* Eventually, you will call a method such as
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* g_task_return_pointer() or g_task_return_error(), which will
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* save the value you give it and then invoke the task's callback
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* function (waiting until the next iteration of the main
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* loop first, if necessary). The caller will pass the #GTask back
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* to the operation's finish function (as a #GAsyncResult), and
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* you can use g_task_propagate_pointer() or the like to extract
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* the return value.
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* </para>
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* <example id="gtask-async"><title>GTask as a GAsyncResult</title>
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* <programlisting>
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* typedef struct {
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* CakeFrostingType frosting;
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* char *message;
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* } DecorationData;
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*
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* static void
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* decoration_data_free (DecorationData *decoration)
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* {
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* g_free (decoration->message);
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* g_slice_free (DecorationData, decoration);
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* }
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*
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* static void
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* baked_cb (Cake *cake,
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* gpointer user_data)
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* {
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* GTask *task = user_data;
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* DecorationData *decoration = g_task_get_task_data (task);
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* GError *error = NULL;
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*
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* if (cake == NULL)
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* {
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* g_task_return_new_error (task, BAKER_ERROR, BAKER_ERROR_NO_FLOUR,
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* "Go to the supermarket");
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* g_object_unref (task);
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* return;
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* }
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*
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* if (!cake_decorate (cake, decoration->frosting, decoration->message, &error))
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* {
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* g_object_unref (cake);
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* /* g_task_return_error() takes ownership of error */
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* g_task_return_error (task, error);
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* g_object_unref (task);
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* return;
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* }
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*
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* g_task_return_pointer (task, cake, g_object_unref);
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* g_object_unref (task);
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* }
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*
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* void
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* baker_bake_cake_async (Baker *self,
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* guint radius,
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* CakeFlavor flavor,
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* CakeFrostingType frosting,
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* const char *message,
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* GCancellable *cancellable,
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* GAsyncReadyCallback callback,
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* gpointer user_data)
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* {
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* GTask *task;
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* DecorationData *decoration;
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* Cake *cake;
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*
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* task = g_task_new (self, cancellable, callback, user_data);
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* if (radius < 3)
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* {
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* g_task_return_new_error (task, BAKER_ERROR, BAKER_ERROR_TOO_SMALL,
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* "%ucm radius cakes are silly",
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* radius);
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* g_object_unref (task);
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* return;
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* }
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*
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* cake = _baker_get_cached_cake (self, radius, flavor, frosting, message);
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* if (cake != NULL)
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* {
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* /* _baker_get_cached_cake() returns a reffed cake */
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* g_task_return_pointer (task, cake, g_object_unref);
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* g_object_unref (task);
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* return;
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* }
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*
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* decoration = g_slice_new (DecorationData);
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* decoration->frosting = frosting;
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* decoration->message = g_strdup (message);
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* g_task_set_task_data (task, decoration, (GDestroyNotify) decoration_data_free);
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*
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* _baker_begin_cake (self, radius, flavor, cancellable, baked_cb, task);
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* }
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*
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* Cake *
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* baker_bake_cake_finish (Baker *self,
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* GAsyncResult *result,
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* GError **error)
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* {
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* g_return_val_if_fail (g_task_is_valid (result, self), NULL);
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*
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* return g_task_propagate_pointer (G_TASK (result), error);
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* }
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* </programlisting>
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* </example>
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* </refsect2>
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* <refsect2>
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* <title>Chained asynchronous operations</title>
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* <para>
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* #GTask also tries to simplify asynchronous operations that
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* internally chain together several smaller asynchronous
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* operations. g_task_get_cancellable(), g_task_get_context(), and
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* g_task_get_priority() allow you to get back the task's
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* #GCancellable, #GMainContext, and <link
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* linkend="io-priority">I/O priority</link> when starting a new
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* subtask, so you don't have to keep track of them yourself.
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* g_task_attach_source() simplifies the case of waiting for a
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* source to fire (automatically using the correct #GMainContext
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* and priority).
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* </para>
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* <example id="gtask-chained"><title>Chained asynchronous operations</title>
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* <programlisting>
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* typedef struct {
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* Cake *cake;
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* CakeFrostingType frosting;
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* char *message;
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* } BakingData;
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*
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* static void
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* decoration_data_free (BakingData *bd)
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* {
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* if (bd->cake)
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* g_object_unref (bd->cake);
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* g_free (bd->message);
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* g_slice_free (BakingData, bd);
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* }
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*
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* static void
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* decorated_cb (Cake *cake,
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* GAsyncResult *result,
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* gpointer user_data)
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* {
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* GTask *task = user_data;
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* GError *error = NULL;
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*
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* if (!cake_decorate_finish (cake, result, &error))
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* {
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* g_object_unref (cake);
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* g_task_return_error (task, error);
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* g_object_unref (task);
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* return;
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* }
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*
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* /* baking_data_free() will drop its ref on the cake, so
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* * we have to take another here to give to the caller.
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* */
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* g_task_return_pointer (result, g_object_ref (cake), g_object_unref);
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* g_object_unref (task);
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* }
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*
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* static void
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* decorator_ready (gpointer user_data)
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* {
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* GTask *task = user_data;
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* BakingData *bd = g_task_get_task_data (task);
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*
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* cake_decorate_async (bd->cake, bd->frosting, bd->message,
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* g_task_get_cancellable (task),
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* decorated_cb, task);
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* }
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*
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* static void
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* baked_cb (Cake *cake,
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* gpointer user_data)
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* {
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* GTask *task = user_data;
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* BakingData *bd = g_task_get_task_data (task);
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* GError *error = NULL;
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*
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* if (cake == NULL)
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* {
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* g_task_return_new_error (task, BAKER_ERROR, BAKER_ERROR_NO_FLOUR,
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* "Go to the supermarket");
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* g_object_unref (task);
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* return;
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* }
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*
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* bd->cake = cake;
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*
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* /* Bail out now if the user has already cancelled */
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* if (g_task_return_error_if_cancelled (task))
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* {
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* g_object_unref (task);
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* return;
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* }
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*
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* if (cake_decorator_available (cake))
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* decorator_ready (task);
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* else
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* {
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* GSource *source;
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*
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* source = cake_decorator_wait_source_new (cake);
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* /* Attach @source to @task's GMainContext and have it call
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* * decorator_ready() when it is ready.
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* */
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* g_task_attach_source (task, source,
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* G_CALLBACK (decorator_ready));
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* g_source_unref (source);
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* }
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* }
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*
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* void
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* baker_bake_cake_async (Baker *self,
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* guint radius,
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* CakeFlavor flavor,
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* CakeFrostingType frosting,
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* const char *message,
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* gint priority,
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* GCancellable *cancellable,
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* GAsyncReadyCallback callback,
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* gpointer user_data)
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* {
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* GTask *task;
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* BakingData *bd;
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*
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* task = g_task_new (self, cancellable, callback, user_data);
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* g_task_set_priority (task, priority);
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*
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* bd = g_slice_new0 (BakingData);
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* bd->frosting = frosting;
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* bd->message = g_strdup (message);
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* g_task_set_task_data (task, bd, (GDestroyNotify) baking_data_free);
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*
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* _baker_begin_cake (self, radius, flavor, cancellable, baked_cb, task);
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* }
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*
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* Cake *
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* baker_bake_cake_finish (Baker *self,
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* GAsyncResult *result,
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* GError **error)
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* {
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* g_return_val_if_fail (g_task_is_valid (result, self), NULL);
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*
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* return g_task_propagate_pointer (G_TASK (result), error);
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* }
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* </programlisting>
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* </example>
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* </refsect2>
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* <refsect2>
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* <title>Asynchronous operations from synchronous ones</title>
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* <para>
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* You can use g_task_run_in_thread() to turn a synchronous
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* operation into an asynchronous one, by running it in a thread
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* which will then dispatch the result back to the caller's
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* #GMainContext when it completes.
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* </para>
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* <example id="gtask-run-in-thread"><title>g_task_run_in_thread()</title>
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* <programlisting>
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* typedef struct {
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* guint radius;
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* CakeFlavor flavor;
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* CakeFrostingType frosting;
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* char *message;
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* } CakeData;
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*
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* static void
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* cake_data_free (CakeData *cake_data)
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* {
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* g_free (cake_data->message);
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* g_slice_free (CakeData, cake_data);
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* }
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*
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* static void
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* bake_cake_thread (GTask *task,
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* gpointer source_object,
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* gpointer task_data,
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* GCancellable *cancellable)
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* {
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* Baker *self = source_object;
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* CakeData *cake_data = task_data;
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* Cake *cake;
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* GError *error = NULL;
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*
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* cake = bake_cake (baker, cake_data->radius, cake_data->flavor,
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* cake_data->frosting, cake_data->message,
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* cancellable, &error);
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* if (cake)
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* g_task_return_pointer (task, cake, g_object_unref);
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* else
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* g_task_return_error (task, error);
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* }
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*
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* void
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* baker_bake_cake_async (Baker *self,
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* guint radius,
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* CakeFlavor flavor,
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* CakeFrostingType frosting,
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* const char *message,
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* GCancellable *cancellable,
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* GAsyncReadyCallback callback,
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* gpointer user_data)
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* {
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* CakeData *cake_data;
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* GTask *task;
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*
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* cake_data = g_slice_new (CakeData);
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* cake_data->radius = radius;
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* cake_data->flavor = flavor;
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* cake_data->frosting = frosting;
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* cake_data->message = g_strdup (message);
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* task = g_task_new (self, cancellable, callback, user_data);
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* g_task_set_task_data (task, cake_data, (GDestroyNotify) cake_data_free);
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* g_task_run_in_thread (task, bake_cake_thread);
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* }
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*
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* Cake *
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* baker_bake_cake_finish (Baker *self,
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* GAsyncResult *result,
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* GError **error)
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* {
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* g_return_val_if_fail (g_task_is_valid (result, self), NULL);
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*
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* return g_task_propagate_pointer (G_TASK (result), error);
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* }
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* </programlisting>
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* </example>
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* </refsect2>
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* <refsect2>
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* <title>Adding cancellability to uncancellable tasks</title>
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* <para>
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* Finally, g_task_run_in_thread() and g_task_run_in_thread_sync()
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* can be used to turn an uncancellable operation into a
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* cancellable one. If you call g_task_set_return_on_cancel(),
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* passing %TRUE, then if the task's #GCancellable is cancelled,
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* it will return control back to the caller immediately, while
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* allowing the task thread to continue running in the background
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* (and simply discarding its result when it finally does finish).
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* Provided that the task thread is careful about how it uses
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* locks and other externally-visible resources, this allows you
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* to make "GLib-friendly" asynchronous and cancellable
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* synchronous variants of blocking APIs.
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* </para>
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* <example id="gtask-cancellable"><title>g_task_set_return_on_cancel()</title>
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* <programlisting>
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* static void
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* bake_cake_thread (GTask *task,
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* gpointer source_object,
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* gpointer task_data,
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* GCancellable *cancellable)
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* {
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* Baker *self = source_object;
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* CakeData *cake_data = task_data;
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* Cake *cake;
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* GError *error = NULL;
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*
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* cake = bake_cake (baker, cake_data->radius, cake_data->flavor,
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* cake_data->frosting, cake_data->message,
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* &error);
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* if (error)
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* {
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* g_task_return_error (task, error);
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* return;
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* }
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*
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* /* If the task has already been cancelled, then we don't
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* * want to add the cake to the cake cache. Likewise, we don't
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* * want to have the task get cancelled in the middle of
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* * updating the cache. g_task_set_return_on_cancel() will
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* * return %TRUE here if it managed to disable return-on-cancel,
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* * or %FALSE if the task was cancelled before it could.
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* */
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* if (g_task_set_return_on_cancel (task, FALSE))
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* {
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* /* If the caller cancels at this point, their
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* * GAsyncReadyCallback won't be invoked until we return,
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* * so we don't have to worry that this code will run at
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* * the same time as that code does. But if there were
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* * other functions that might look at the cake cache,
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* * then we'd probably need a GMutex here as well.
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* */
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* baker_add_cake_to_cache (baker, cake);
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* g_task_return_pointer (task, cake, g_object_unref);
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* }
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* }
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*
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* void
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* baker_bake_cake_async (Baker *self,
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* guint radius,
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* CakeFlavor flavor,
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* CakeFrostingType frosting,
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* const char *message,
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* GCancellable *cancellable,
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* GAsyncReadyCallback callback,
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* gpointer user_data)
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* {
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* CakeData *cake_data;
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* GTask *task;
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*
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* cake_data = g_slice_new (CakeData);
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* /* ... */
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*
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* task = g_task_new (self, cancellable, callback, user_data);
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* g_task_set_task_data (task, cake_data, (GDestroyNotify) cake_data_free);
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* g_task_set_return_on_cancel (task, TRUE);
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* g_task_run_in_thread (task, bake_cake_thread);
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* }
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*
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* Cake *
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* baker_bake_cake_sync (Baker *self,
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* guint radius,
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* CakeFlavor flavor,
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* CakeFrostingType frosting,
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* const char *message,
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* GCancellable *cancellable,
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* GError **error)
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* {
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* CakeData *cake_data;
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* GTask *task;
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* Cake *cake;
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*
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* cake_data = g_slice_new (CakeData);
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* /* ... */
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*
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* task = g_task_new (self, cancellable, NULL, NULL);
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* g_task_set_task_data (task, cake_data, (GDestroyNotify) cake_data_free);
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* g_task_set_return_on_cancel (task, TRUE);
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* g_task_run_in_thread_sync (task, bake_cake_thread);
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*
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* cake = g_task_propagate_pointer (task, error);
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* g_object_unref (task);
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* return cake;
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* }
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* </programlisting>
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* </example>
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* </refsect2>
|
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* <refsect2>
|
|
* <title>Porting from <literal>GSimpleAsyncResult</literal></title>
|
|
* <para>
|
|
* #GTask's API attempts to be simpler than #GSimpleAsyncResult's
|
|
* in several ways:
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* </para>
|
|
* <itemizedlist>
|
|
* <listitem><para>
|
|
* You can save task-specific data with g_task_set_task_data(), and
|
|
* retrieve it later with g_task_get_task_data(). This replaces the
|
|
* abuse of g_simple_async_result_set_op_res_gpointer() for the same
|
|
* purpose with #GSimpleAsyncResult.
|
|
* </para></listitem>
|
|
* <listitem><para>
|
|
* In addition to the task data, #GTask also keeps track of the
|
|
* <link linkend="io-priority">priority</link>, #GCancellable, and
|
|
* #GMainContext associated with the task, so tasks that consist of
|
|
* a chain of simpler asynchronous operations will have easy access
|
|
* to those values when starting each sub-task.
|
|
* </para></listitem>
|
|
* <listitem><para>
|
|
* g_task_return_error_if_cancelled() provides simplified
|
|
* handling for cancellation. In addition, cancellation
|
|
* overrides any other #GTask return value by default, like
|
|
* #GSimpleAsyncResult does when
|
|
* g_simple_async_result_set_check_cancellable() is called.
|
|
* (You can use g_task_set_check_cancellable() to turn off that
|
|
* behavior.) On the other hand, g_task_run_in_thread()
|
|
* guarantees that it will always run your
|
|
* <literal>task_func</literal>, even if the task's #GCancellable
|
|
* is already cancelled before the task gets a chance to run;
|
|
* you can start your <literal>task_func</literal> with a
|
|
* g_task_return_error_if_cancelled() check if you need the
|
|
* old behavior.
|
|
* </para></listitem>
|
|
* <listitem><para>
|
|
* The "return" methods (eg, g_task_return_pointer())
|
|
* automatically cause the task to be "completed" as well, and
|
|
* there is no need to worry about the "complete" vs "complete
|
|
* in idle" distinction. (#GTask automatically figures out
|
|
* whether the task's callback can be invoked directly, or
|
|
* if it needs to be sent to another #GMainContext, or delayed
|
|
* until the next iteration of the current #GMainContext.)
|
|
* </para></listitem>
|
|
* <listitem><para>
|
|
* The "finish" functions for #GTask-based operations are generally
|
|
* much simpler than #GSimpleAsyncResult ones, normally consisting
|
|
* of only a single call to g_task_propagate_pointer() or the like.
|
|
* Since g_task_propagate_pointer() "steals" the return value from
|
|
* the #GTask, it is not necessary to juggle pointers around to
|
|
* prevent it from being freed twice.
|
|
* </para></listitem>
|
|
* <listitem><para>
|
|
* With #GSimpleAsyncResult, it was common to call
|
|
* g_simple_async_result_propagate_error() from the
|
|
* <literal>_finish()</literal> wrapper function, and have
|
|
* virtual method implementations only deal with successful
|
|
* returns. This behavior is deprecated, because it makes it
|
|
* difficult for a subclass to chain to a parent class's async
|
|
* methods. Instead, the wrapper function should just be a
|
|
* simple wrapper, and the virtual method should call an
|
|
* appropriate <literal>g_task_propagate_</literal> function.
|
|
* Note that wrapper methods can now use
|
|
* g_async_result_legacy_propagate_error() to do old-style
|
|
* #GSimpleAsyncResult error-returning behavior, and
|
|
* g_async_result_is_tagged() to check if a result is tagged as
|
|
* having come from the <literal>_async()</literal> wrapper
|
|
* function (for "short-circuit" results, such as when passing
|
|
* 0 to g_input_stream_read_async()).
|
|
* </para></listitem>
|
|
* </itemizedlist>
|
|
* </refsect2>
|
|
*/
|
|
|
|
/**
|
|
* GTask:
|
|
*
|
|
* The opaque object representing a synchronous or asynchronous task
|
|
* and its result.
|
|
*/
|
|
|
|
struct _GTask {
|
|
GObject parent_instance;
|
|
|
|
gpointer source_object;
|
|
gpointer source_tag;
|
|
|
|
gpointer task_data;
|
|
GDestroyNotify task_data_destroy;
|
|
|
|
GMainContext *context;
|
|
guint64 creation_time;
|
|
gint priority;
|
|
GCancellable *cancellable;
|
|
gboolean check_cancellable;
|
|
|
|
GAsyncReadyCallback callback;
|
|
gpointer callback_data;
|
|
|
|
GTaskThreadFunc task_func;
|
|
GMutex lock;
|
|
GCond cond;
|
|
gboolean return_on_cancel;
|
|
gboolean thread_cancelled;
|
|
gboolean synchronous;
|
|
gboolean thread_complete;
|
|
gboolean blocking_other_task;
|
|
|
|
GError *error;
|
|
union {
|
|
gpointer pointer;
|
|
gssize size;
|
|
gboolean boolean;
|
|
} result;
|
|
GDestroyNotify result_destroy;
|
|
gboolean result_set;
|
|
};
|
|
|
|
#define G_TASK_IS_THREADED(task) ((task)->task_func != NULL)
|
|
|
|
struct _GTaskClass
|
|
{
|
|
GObjectClass parent_class;
|
|
};
|
|
|
|
static void g_task_thread_pool_resort (void);
|
|
|
|
static void g_task_async_result_iface_init (GAsyncResultIface *iface);
|
|
static void g_task_thread_pool_init (void);
|
|
|
|
G_DEFINE_TYPE_WITH_CODE (GTask, g_task, G_TYPE_OBJECT,
|
|
G_IMPLEMENT_INTERFACE (G_TYPE_ASYNC_RESULT,
|
|
g_task_async_result_iface_init);
|
|
g_task_thread_pool_init ();)
|
|
|
|
static GThreadPool *task_pool;
|
|
static GMutex task_pool_mutex;
|
|
static GPrivate task_private = G_PRIVATE_INIT (NULL);
|
|
|
|
static void
|
|
g_task_init (GTask *task)
|
|
{
|
|
task->check_cancellable = TRUE;
|
|
}
|
|
|
|
static void
|
|
g_task_finalize (GObject *object)
|
|
{
|
|
GTask *task = G_TASK (object);
|
|
|
|
g_clear_object (&task->source_object);
|
|
g_clear_object (&task->cancellable);
|
|
|
|
if (task->context)
|
|
g_main_context_unref (task->context);
|
|
|
|
if (task->task_data_destroy)
|
|
task->task_data_destroy (task->task_data);
|
|
|
|
if (task->result_destroy && task->result.pointer)
|
|
task->result_destroy (task->result.pointer);
|
|
|
|
if (task->error)
|
|
g_error_free (task->error);
|
|
|
|
if (G_TASK_IS_THREADED (task))
|
|
{
|
|
g_mutex_clear (&task->lock);
|
|
g_cond_clear (&task->cond);
|
|
}
|
|
|
|
G_OBJECT_CLASS (g_task_parent_class)->finalize (object);
|
|
}
|
|
|
|
/**
|
|
* g_task_new:
|
|
* @source_object: (allow-none) (type GObject): the #GObject that owns
|
|
* this task, or %NULL.
|
|
* @cancellable: (allow-none): optional #GCancellable object, %NULL to ignore.
|
|
* @callback: (scope async): a #GAsyncReadyCallback.
|
|
* @callback_data: (closure): user data passed to @callback.
|
|
*
|
|
* Creates a #GTask acting on @source_object, which will eventually be
|
|
* used to invoke @callback in the current <link
|
|
* linkend="g-main-context-push-thread-default">thread-default main
|
|
* context</link>.
|
|
*
|
|
* Call this in the "start" method of your asynchronous method, and
|
|
* pass the #GTask around throughout the asynchronous operation. You
|
|
* can use g_task_set_task_data() to attach task-specific data to the
|
|
* object, which you can retrieve later via g_task_get_task_data().
|
|
*
|
|
* By default, if @cancellable is cancelled, then the return value of
|
|
* the task will always be %G_IO_ERROR_CANCELLED, even if the task had
|
|
* already completed before the cancellation. This allows for
|
|
* simplified handling in cases where cancellation may imply that
|
|
* other objects that the task depends on have been destroyed. If you
|
|
* do not want this behavior, you can use
|
|
* g_task_set_check_cancellable() to change it.
|
|
*
|
|
* Returns: a #GTask.
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
GTask *
|
|
g_task_new (gpointer source_object,
|
|
GCancellable *cancellable,
|
|
GAsyncReadyCallback callback,
|
|
gpointer callback_data)
|
|
{
|
|
GTask *task;
|
|
GSource *source;
|
|
|
|
task = g_object_new (G_TYPE_TASK, NULL);
|
|
task->source_object = source_object ? g_object_ref (source_object) : NULL;
|
|
task->cancellable = cancellable ? g_object_ref (cancellable) : NULL;
|
|
task->callback = callback;
|
|
task->callback_data = callback_data;
|
|
task->context = g_main_context_ref_thread_default ();
|
|
|
|
source = g_main_current_source ();
|
|
if (source)
|
|
task->creation_time = g_source_get_time (source);
|
|
|
|
return task;
|
|
}
|
|
|
|
/**
|
|
* g_task_report_error:
|
|
* @source_object: (allow-none) (type GObject): the #GObject that owns
|
|
* this task, or %NULL.
|
|
* @callback: (scope async): a #GAsyncReadyCallback.
|
|
* @callback_data: (closure): user data passed to @callback.
|
|
* @source_tag: an opaque pointer indicating the source of this task
|
|
* @error: (transfer full): error to report
|
|
*
|
|
* Creates a #GTask and then immediately calls g_task_return_error()
|
|
* on it. Use this in the wrapper function of an asynchronous method
|
|
* when you want to avoid even calling the virtual method. You can
|
|
* then use g_async_result_is_tagged() in the finish method wrapper to
|
|
* check if the result there is tagged as having been created by the
|
|
* wrapper method, and deal with it appropriately if so.
|
|
*
|
|
* See also g_task_report_new_error().
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
void
|
|
g_task_report_error (gpointer source_object,
|
|
GAsyncReadyCallback callback,
|
|
gpointer callback_data,
|
|
gpointer source_tag,
|
|
GError *error)
|
|
{
|
|
GTask *task;
|
|
|
|
task = g_task_new (source_object, NULL, callback, callback_data);
|
|
g_task_set_source_tag (task, source_tag);
|
|
g_task_return_error (task, error);
|
|
g_object_unref (task);
|
|
}
|
|
|
|
/**
|
|
* g_task_report_new_error:
|
|
* @source_object: (allow-none) (type GObject): the #GObject that owns
|
|
* this task, or %NULL.
|
|
* @callback: (scope async): a #GAsyncReadyCallback.
|
|
* @callback_data: (closure): user data passed to @callback.
|
|
* @source_tag: an opaque pointer indicating the source of this task
|
|
* @domain: a #GQuark.
|
|
* @code: an error code.
|
|
* @format: a string with format characters.
|
|
* @...: a list of values to insert into @format.
|
|
*
|
|
* Creates a #GTask and then immediately calls
|
|
* g_task_return_new_error() on it. Use this in the wrapper function
|
|
* of an asynchronous method when you want to avoid even calling the
|
|
* virtual method. You can then use g_async_result_is_tagged() in the
|
|
* finish method wrapper to check if the result there is tagged as
|
|
* having been created by the wrapper method, and deal with it
|
|
* appropriately if so.
|
|
*
|
|
* See also g_task_report_error().
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
void
|
|
g_task_report_new_error (gpointer source_object,
|
|
GAsyncReadyCallback callback,
|
|
gpointer callback_data,
|
|
gpointer source_tag,
|
|
GQuark domain,
|
|
gint code,
|
|
const char *format,
|
|
...)
|
|
{
|
|
GError *error;
|
|
va_list ap;
|
|
|
|
va_start (ap, format);
|
|
error = g_error_new_valist (domain, code, format, ap);
|
|
va_end (ap);
|
|
|
|
g_task_report_error (source_object, callback, callback_data,
|
|
source_tag, error);
|
|
}
|
|
|
|
/**
|
|
* g_task_set_task_data:
|
|
* @task: the #GTask
|
|
* @task_data: (allow-none): task-specific data
|
|
* @task_data_destroy: (allow-none): #GDestroyNotify for @task_data
|
|
*
|
|
* Sets @task's task data (freeing the existing task data, if any).
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
void
|
|
g_task_set_task_data (GTask *task,
|
|
gpointer task_data,
|
|
GDestroyNotify task_data_destroy)
|
|
{
|
|
if (task->task_data_destroy)
|
|
task->task_data_destroy (task->task_data);
|
|
|
|
task->task_data = task_data;
|
|
task->task_data_destroy = task_data_destroy;
|
|
}
|
|
|
|
/**
|
|
* g_task_set_priority:
|
|
* @task: the #GTask
|
|
* @priority: the <link linkend="io-priority">priority</link>
|
|
* of the request.
|
|
*
|
|
* Sets @task's priority. If you do not call this, it will default to
|
|
* %G_PRIORITY_DEFAULT.
|
|
*
|
|
* This will affect the priority of #GSources created with
|
|
* g_task_attach_source() and the scheduling of tasks run in threads,
|
|
* and can also be explicitly retrieved later via
|
|
* g_task_get_priority().
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
void
|
|
g_task_set_priority (GTask *task,
|
|
gint priority)
|
|
{
|
|
task->priority = priority;
|
|
}
|
|
|
|
/**
|
|
* g_task_set_check_cancellable:
|
|
* @task: the #GTask
|
|
* @check_cancellable: whether #GTask will check the state of
|
|
* its #GCancellable for you.
|
|
*
|
|
* Sets or clears @task's check-cancellable flag. If this is %TRUE
|
|
* (the default), then g_task_propagate_pointer(), etc, and
|
|
* g_task_had_error() will check the task's #GCancellable first, and
|
|
* if it has been cancelled, then they will consider the task to have
|
|
* returned an "Operation was cancelled" error
|
|
* (%G_IO_ERROR_CANCELLED), regardless of any other error or return
|
|
* value the task may have had.
|
|
*
|
|
* If @check_cancellable is %FALSE, then the #GTask will not check the
|
|
* cancellable itself, and it is up to @task's owner to do this (eg,
|
|
* via g_task_return_error_if_cancelled()).
|
|
*
|
|
* If you are using g_task_set_return_on_cancel() as well, then
|
|
* you must leave check-cancellable set %TRUE.
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
void
|
|
g_task_set_check_cancellable (GTask *task,
|
|
gboolean check_cancellable)
|
|
{
|
|
g_return_if_fail (check_cancellable || !task->return_on_cancel);
|
|
|
|
task->check_cancellable = check_cancellable;
|
|
}
|
|
|
|
static void g_task_thread_complete (GTask *task);
|
|
|
|
/**
|
|
* g_task_set_return_on_cancel:
|
|
* @task: the #GTask
|
|
* @return_on_cancel: whether the task returns automatically when
|
|
* it is cancelled.
|
|
*
|
|
* Sets or clears @task's return-on-cancel flag. This is only
|
|
* meaningful for tasks run via g_task_run_in_thread() or
|
|
* g_task_run_in_thread_sync().
|
|
*
|
|
* If @return_on_cancel is %TRUE, then cancelling @task's
|
|
* #GCancellable will immediately cause it to return, as though the
|
|
* task's #GTaskThreadFunc had called
|
|
* g_task_return_error_if_cancelled() and then returned.
|
|
*
|
|
* This allows you to create a cancellable wrapper around an
|
|
* uninterruptable function. The #GTaskThreadFunc just needs to be
|
|
* careful that it does not modify any externally-visible state after
|
|
* it has been cancelled. To do that, the thread should call
|
|
* g_task_set_return_on_cancel() again to (atomically) set
|
|
* return-on-cancel %FALSE before making externally-visible changes;
|
|
* if the task gets cancelled before the return-on-cancel flag could
|
|
* be changed, g_task_set_return_on_cancel() will indicate this by
|
|
* returning %FALSE.
|
|
*
|
|
* You can disable and re-enable this flag multiple times if you wish.
|
|
* If the task's #GCancellable is cancelled while return-on-cancel is
|
|
* %FALSE, then calling g_task_set_return_on_cancel() to set it %TRUE
|
|
* again will cause the task to be cancelled at that point.
|
|
*
|
|
* If the task's #GCancellable is already cancelled before you call
|
|
* g_task_run_in_thread()/g_task_run_in_thread_sync(), then the
|
|
* #GTaskThreadFunc will still be run (for consistency), but the task
|
|
* will also be completed right away.
|
|
*
|
|
* Returns: %TRUE if @task's return-on-cancel flag was changed to
|
|
* match @return_on_cancel. %FALSE if @task has already been
|
|
* cancelled.
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
gboolean
|
|
g_task_set_return_on_cancel (GTask *task,
|
|
gboolean return_on_cancel)
|
|
{
|
|
g_return_val_if_fail (task->check_cancellable || !return_on_cancel, FALSE);
|
|
|
|
if (!G_TASK_IS_THREADED (task))
|
|
{
|
|
task->return_on_cancel = return_on_cancel;
|
|
return TRUE;
|
|
}
|
|
|
|
g_mutex_lock (&task->lock);
|
|
if (task->thread_cancelled)
|
|
{
|
|
if (return_on_cancel && !task->return_on_cancel)
|
|
{
|
|
g_mutex_unlock (&task->lock);
|
|
g_task_thread_complete (task);
|
|
}
|
|
else
|
|
g_mutex_unlock (&task->lock);
|
|
return FALSE;
|
|
}
|
|
task->return_on_cancel = return_on_cancel;
|
|
g_mutex_unlock (&task->lock);
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
/**
|
|
* g_task_set_source_tag:
|
|
* @task: the #GTask
|
|
* @source_tag: an opaque pointer indicating the source of this task
|
|
*
|
|
* Sets @task's source tag. You can use this to tag a task return
|
|
* value with a particular pointer (usually a pointer to the function
|
|
* doing the tagging) and then later check it using
|
|
* g_task_get_source_tag() (or g_async_result_is_tagged()) in the
|
|
* task's "finish" function, to figure out if the response came from a
|
|
* particular place.
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
void
|
|
g_task_set_source_tag (GTask *task,
|
|
gpointer source_tag)
|
|
{
|
|
task->source_tag = source_tag;
|
|
}
|
|
|
|
/**
|
|
* g_task_get_source_object:
|
|
* @task: a #GTask
|
|
*
|
|
* Gets the source object from @task. Like
|
|
* g_async_result_get_source_object(), but does not ref the object.
|
|
*
|
|
* Returns: (transfer none) (type GObject): @task's source object, or %NULL
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
gpointer
|
|
g_task_get_source_object (GTask *task)
|
|
{
|
|
return task->source_object;
|
|
}
|
|
|
|
static GObject *
|
|
g_task_ref_source_object (GAsyncResult *res)
|
|
{
|
|
GTask *task = G_TASK (res);
|
|
|
|
if (task->source_object)
|
|
return g_object_ref (task->source_object);
|
|
else
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* g_task_get_task_data:
|
|
* @task: a #GTask
|
|
*
|
|
* Gets @task's <literal>task_data</literal>.
|
|
*
|
|
* Returns: (transfer none): @task's <literal>task_data</literal>.
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
gpointer
|
|
g_task_get_task_data (GTask *task)
|
|
{
|
|
return task->task_data;
|
|
}
|
|
|
|
/**
|
|
* g_task_get_priority:
|
|
* @task: a #GTask
|
|
*
|
|
* Gets @task's priority
|
|
*
|
|
* Returns: @task's priority
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
gint
|
|
g_task_get_priority (GTask *task)
|
|
{
|
|
return task->priority;
|
|
}
|
|
|
|
/**
|
|
* g_task_get_context:
|
|
* @task: a #GTask
|
|
*
|
|
* Gets the #GMainContext that @task will return its result in (that
|
|
* is, the context that was the <link
|
|
* linkend="g-main-context-push-thread-default">thread-default main
|
|
* context</link> at the point when @task was created).
|
|
*
|
|
* This will always return a non-%NULL value, even if the task's
|
|
* context is the default #GMainContext.
|
|
*
|
|
* Returns: (transfer none): @task's #GMainContext
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
GMainContext *
|
|
g_task_get_context (GTask *task)
|
|
{
|
|
return task->context;
|
|
}
|
|
|
|
/**
|
|
* g_task_get_cancellable:
|
|
* @task: a #GTask
|
|
*
|
|
* Gets @task's #GCancellable
|
|
*
|
|
* Returns: (transfer none): @task's #GCancellable
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
GCancellable *
|
|
g_task_get_cancellable (GTask *task)
|
|
{
|
|
return task->cancellable;
|
|
}
|
|
|
|
/**
|
|
* g_task_get_check_cancellable:
|
|
* @task: the #GTask
|
|
*
|
|
* Gets @task's check-cancellable flag. See
|
|
* g_task_set_check_cancellable() for more details.
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
gboolean
|
|
g_task_get_check_cancellable (GTask *task)
|
|
{
|
|
return task->check_cancellable;
|
|
}
|
|
|
|
/**
|
|
* g_task_get_return_on_cancel:
|
|
* @task: the #GTask
|
|
*
|
|
* Gets @task's return-on-cancel flag. See
|
|
* g_task_set_return_on_cancel() for more details.
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
gboolean
|
|
g_task_get_return_on_cancel (GTask *task)
|
|
{
|
|
return task->return_on_cancel;
|
|
}
|
|
|
|
/**
|
|
* g_task_get_source_tag:
|
|
* @task: a #GTask
|
|
*
|
|
* Gets @task's source tag. See g_task_set_source_tag().
|
|
*
|
|
* Return value: (transfer none): @task's source tag
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
gpointer
|
|
g_task_get_source_tag (GTask *task)
|
|
{
|
|
return task->source_tag;
|
|
}
|
|
|
|
|
|
static void
|
|
g_task_return_now (GTask *task)
|
|
{
|
|
g_main_context_push_thread_default (task->context);
|
|
task->callback (task->source_object,
|
|
G_ASYNC_RESULT (task),
|
|
task->callback_data);
|
|
g_main_context_pop_thread_default (task->context);
|
|
}
|
|
|
|
static gboolean
|
|
complete_in_idle_cb (gpointer task)
|
|
{
|
|
g_task_return_now (task);
|
|
g_object_unref (task);
|
|
return FALSE;
|
|
}
|
|
|
|
typedef enum {
|
|
G_TASK_RETURN_SUCCESS,
|
|
G_TASK_RETURN_ERROR,
|
|
G_TASK_RETURN_FROM_THREAD
|
|
} GTaskReturnType;
|
|
|
|
static void
|
|
g_task_return (GTask *task,
|
|
GTaskReturnType type)
|
|
{
|
|
GSource *source;
|
|
|
|
if (type == G_TASK_RETURN_SUCCESS)
|
|
task->result_set = TRUE;
|
|
|
|
if (task->synchronous || !task->callback)
|
|
return;
|
|
|
|
/* Normally we want to invoke the task's callback when its return
|
|
* value is set. But if the task is running in a thread, then we
|
|
* want to wait until after the task_func returns, to simplify
|
|
* locking/refcounting/etc.
|
|
*/
|
|
if (G_TASK_IS_THREADED (task) && type != G_TASK_RETURN_FROM_THREAD)
|
|
return;
|
|
|
|
g_object_ref (task);
|
|
|
|
/* See if we can complete the task immediately. First, we have to be
|
|
* running inside the task's thread/GMainContext.
|
|
*/
|
|
source = g_main_current_source ();
|
|
if (source && g_source_get_context (source) == task->context)
|
|
{
|
|
/* Second, we can only complete immediately if this is not the
|
|
* same iteration of the main loop that the task was created in.
|
|
*/
|
|
if (g_source_get_time (source) > task->creation_time)
|
|
{
|
|
g_task_return_now (task);
|
|
g_object_unref (task);
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* Otherwise, complete in the next iteration */
|
|
source = g_idle_source_new ();
|
|
g_task_attach_source (task, source, complete_in_idle_cb);
|
|
g_source_unref (source);
|
|
}
|
|
|
|
|
|
/**
|
|
* GTaskThreadFunc:
|
|
* @task: the #GTask
|
|
* @source_object: (type GObject): @task's source object
|
|
* @task_data: @task's task data
|
|
* @cancellable: @task's #GCancellable, or %NULL
|
|
*
|
|
* The prototype for a task function to be run in a thread via
|
|
* g_task_run_in_thread() or g_task_run_in_thread_sync().
|
|
*
|
|
* If the return-on-cancel flag is set on @task, and @cancellable gets
|
|
* cancelled, then the #GTask will be completed immediately (as though
|
|
* g_task_return_error_if_cancelled() had been called), without
|
|
* waiting for the task function to complete. However, the task
|
|
* function will continue running in its thread in the background. The
|
|
* function therefore needs to be careful about how it uses
|
|
* externally-visible state in this case. See
|
|
* g_task_set_return_on_cancel() for more details.
|
|
*
|
|
* Other than in that case, @task will be completed when the
|
|
* #GTaskThreadFunc returns, <emphasis>not</emphasis> when it calls
|
|
* a <literal>g_task_return_</literal> function.
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
|
|
static void task_thread_cancelled (GCancellable *cancellable,
|
|
gpointer user_data);
|
|
|
|
static void
|
|
g_task_thread_complete (GTask *task)
|
|
{
|
|
g_mutex_lock (&task->lock);
|
|
if (task->thread_complete)
|
|
{
|
|
/* The task belatedly completed after having been cancelled
|
|
* (or was cancelled in the midst of being completed).
|
|
*/
|
|
g_mutex_unlock (&task->lock);
|
|
return;
|
|
}
|
|
|
|
task->thread_complete = TRUE;
|
|
|
|
if (task->blocking_other_task)
|
|
{
|
|
g_mutex_lock (&task_pool_mutex);
|
|
g_thread_pool_set_max_threads (task_pool,
|
|
g_thread_pool_get_max_threads (task_pool) - 1,
|
|
NULL);
|
|
g_mutex_unlock (&task_pool_mutex);
|
|
}
|
|
g_mutex_unlock (&task->lock);
|
|
|
|
if (task->cancellable)
|
|
g_signal_handlers_disconnect_by_func (task->cancellable, task_thread_cancelled, task);
|
|
|
|
if (task->synchronous)
|
|
g_cond_signal (&task->cond);
|
|
else
|
|
g_task_return (task, G_TASK_RETURN_FROM_THREAD);
|
|
}
|
|
|
|
static void
|
|
g_task_thread_pool_thread (gpointer thread_data,
|
|
gpointer pool_data)
|
|
{
|
|
GTask *task = thread_data;
|
|
|
|
g_private_set (&task_private, task);
|
|
|
|
task->task_func (task, task->source_object, task->task_data,
|
|
task->cancellable);
|
|
g_task_thread_complete (task);
|
|
|
|
g_private_set (&task_private, NULL);
|
|
g_object_unref (task);
|
|
}
|
|
|
|
static void
|
|
task_thread_cancelled (GCancellable *cancellable,
|
|
gpointer user_data)
|
|
{
|
|
GTask *task = user_data;
|
|
|
|
g_task_thread_pool_resort ();
|
|
|
|
g_mutex_lock (&task->lock);
|
|
task->thread_cancelled = TRUE;
|
|
|
|
if (!task->return_on_cancel)
|
|
{
|
|
g_mutex_unlock (&task->lock);
|
|
return;
|
|
}
|
|
|
|
/* We don't actually set task->error; g_task_return_error() doesn't
|
|
* use a lock, and g_task_propagate_error() will call
|
|
* g_cancellable_set_error_if_cancelled() anyway.
|
|
*/
|
|
g_mutex_unlock (&task->lock);
|
|
g_task_thread_complete (task);
|
|
}
|
|
|
|
static void
|
|
task_thread_cancelled_disconnect_notify (gpointer task,
|
|
GClosure *closure)
|
|
{
|
|
g_object_unref (task);
|
|
}
|
|
|
|
static void
|
|
g_task_start_task_thread (GTask *task,
|
|
GTaskThreadFunc task_func)
|
|
{
|
|
g_mutex_init (&task->lock);
|
|
g_cond_init (&task->cond);
|
|
|
|
g_mutex_lock (&task->lock);
|
|
|
|
task->task_func = task_func;
|
|
|
|
if (task->cancellable)
|
|
{
|
|
if (task->return_on_cancel &&
|
|
g_cancellable_set_error_if_cancelled (task->cancellable,
|
|
&task->error))
|
|
{
|
|
task->thread_cancelled = task->thread_complete = TRUE;
|
|
g_thread_pool_push (task_pool, g_object_ref (task), NULL);
|
|
return;
|
|
}
|
|
|
|
g_signal_connect_data (task->cancellable, "cancelled",
|
|
G_CALLBACK (task_thread_cancelled),
|
|
g_object_ref (task),
|
|
task_thread_cancelled_disconnect_notify, 0);
|
|
}
|
|
|
|
g_thread_pool_push (task_pool, g_object_ref (task), &task->error);
|
|
if (task->error)
|
|
task->thread_complete = TRUE;
|
|
else if (g_private_get (&task_private))
|
|
{
|
|
/* This thread is being spawned from another GTask thread, so
|
|
* bump up max-threads so we don't starve.
|
|
*/
|
|
g_mutex_lock (&task_pool_mutex);
|
|
if (g_thread_pool_set_max_threads (task_pool,
|
|
g_thread_pool_get_max_threads (task_pool) + 1,
|
|
NULL))
|
|
task->blocking_other_task = TRUE;
|
|
g_mutex_unlock (&task_pool_mutex);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* g_task_run_in_thread:
|
|
* @task: a #GTask
|
|
* @task_func: a #GTaskThreadFunc
|
|
*
|
|
* Runs @task_func in another thread. When @task_func returns, @task's
|
|
* #GAsyncReadyCallback will be invoked in @task's #GMainContext.
|
|
*
|
|
* This takes a ref on @task until the task completes.
|
|
*
|
|
* See #GTaskThreadFunc for more details about how @task_func is handled.
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
void
|
|
g_task_run_in_thread (GTask *task,
|
|
GTaskThreadFunc task_func)
|
|
{
|
|
g_return_if_fail (G_IS_TASK (task));
|
|
|
|
g_object_ref (task);
|
|
g_task_start_task_thread (task, task_func);
|
|
|
|
/* The task may already be cancelled, or g_thread_pool_push() may
|
|
* have failed.
|
|
*/
|
|
if (task->thread_complete)
|
|
{
|
|
g_mutex_unlock (&task->lock);
|
|
g_task_return (task, G_TASK_RETURN_FROM_THREAD);
|
|
}
|
|
else
|
|
g_mutex_unlock (&task->lock);
|
|
|
|
g_object_unref (task);
|
|
}
|
|
|
|
/**
|
|
* g_task_run_in_thread_sync:
|
|
* @task: a #GTask
|
|
* @task_func: a #GTaskThreadFunc
|
|
*
|
|
* Runs @task_func in another thread, and waits for it to return or be
|
|
* cancelled. You can use g_task_propagate_pointer(), etc, afterward
|
|
* to get the result of @task_func.
|
|
*
|
|
* See #GTaskThreadFunc for more details about how @task_func is handled.
|
|
*
|
|
* Normally this is used with tasks created with a %NULL
|
|
* <literal>callback</literal>, but note that even if the task does
|
|
* have a callback, it will not be invoked when @task_func returns.
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
void
|
|
g_task_run_in_thread_sync (GTask *task,
|
|
GTaskThreadFunc task_func)
|
|
{
|
|
g_return_if_fail (G_IS_TASK (task));
|
|
|
|
g_object_ref (task);
|
|
|
|
task->synchronous = TRUE;
|
|
g_task_start_task_thread (task, task_func);
|
|
|
|
while (!task->thread_complete)
|
|
g_cond_wait (&task->cond, &task->lock);
|
|
|
|
g_mutex_unlock (&task->lock);
|
|
g_object_unref (task);
|
|
}
|
|
|
|
/**
|
|
* g_task_attach_source:
|
|
* @task: a #GTask
|
|
* @source: the source to attach
|
|
* @callback: the callback to invoke when @source triggers
|
|
*
|
|
* A utility function for dealing with async operations where you need
|
|
* to wait for a #GSource to trigger. Attaches @source to @task's
|
|
* #GMainContext with @task's <link
|
|
* linkend="io-priority">priority</link>, and sets @source's callback
|
|
* to @callback, with @task as the callback's
|
|
* <literal>user_data</literal>.
|
|
*
|
|
* This takes a reference on @task until @source is destroyed.
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
void
|
|
g_task_attach_source (GTask *task,
|
|
GSource *source,
|
|
GSourceFunc callback)
|
|
{
|
|
g_source_set_callback (source, callback,
|
|
g_object_ref (task), g_object_unref);
|
|
g_source_set_priority (source, task->priority);
|
|
g_source_attach (source, task->context);
|
|
}
|
|
|
|
|
|
static gboolean
|
|
g_task_propagate_error (GTask *task,
|
|
GError **error)
|
|
{
|
|
if (task->check_cancellable &&
|
|
g_cancellable_set_error_if_cancelled (task->cancellable, error))
|
|
return TRUE;
|
|
else if (task->error)
|
|
{
|
|
g_propagate_error (error, task->error);
|
|
task->error = NULL;
|
|
return TRUE;
|
|
}
|
|
else
|
|
return FALSE;
|
|
}
|
|
|
|
/**
|
|
* g_task_return_pointer:
|
|
* @task: a #GTask
|
|
* @result: (allow-none) (transfer full): the pointer result of a task
|
|
* function
|
|
* @result_destroy: (allow-none): a #GDestroyNotify function.
|
|
*
|
|
* Sets @task's result to @result and completes the task. If @result
|
|
* is not %NULL, then @result_destroy will be used to free @result if
|
|
* the caller does not take ownership of it with
|
|
* g_task_propagate_pointer().
|
|
*
|
|
* "Completes the task" means that for an ordinary asynchronous task
|
|
* it will either invoke the task's callback, or else queue that
|
|
* callback to be invoked in the proper #GMainContext, or in the next
|
|
* iteration of the current #GMainContext. For a task run via
|
|
* g_task_run_in_thread() or g_task_run_in_thread_sync(), calling this
|
|
* method will save @result to be returned to the caller later, but
|
|
* the task will not actually be completed until the #GTaskThreadFunc
|
|
* exits.
|
|
*
|
|
* Note that since the task may be completed before returning from
|
|
* g_task_return_pointer(), you cannot assume that @result is still
|
|
* valid after calling this, unless you are still holding another
|
|
* reference on it.
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
void
|
|
g_task_return_pointer (GTask *task,
|
|
gpointer result,
|
|
GDestroyNotify result_destroy)
|
|
{
|
|
g_return_if_fail (task->result_set == FALSE);
|
|
|
|
task->result.pointer = result;
|
|
task->result_destroy = result_destroy;
|
|
|
|
g_task_return (task, G_TASK_RETURN_SUCCESS);
|
|
}
|
|
|
|
/**
|
|
* g_task_propagate_pointer:
|
|
* @task: a #GTask
|
|
* @error: return location for a #GError
|
|
*
|
|
* Gets the result of @task as a pointer, and transfers ownership
|
|
* of that value to the caller.
|
|
*
|
|
* If the task resulted in an error, or was cancelled, then this will
|
|
* instead return %NULL and set @error.
|
|
*
|
|
* Since this method transfers ownership of the return value (or
|
|
* error) to the caller, you may only call it once.
|
|
*
|
|
* Returns: (transfer full): the task result, or %NULL on error
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
gpointer
|
|
g_task_propagate_pointer (GTask *task,
|
|
GError **error)
|
|
{
|
|
if (g_task_propagate_error (task, error))
|
|
return NULL;
|
|
|
|
g_return_val_if_fail (task->result_set == TRUE, NULL);
|
|
|
|
task->result_destroy = NULL;
|
|
task->result_set = FALSE;
|
|
return task->result.pointer;
|
|
}
|
|
|
|
/**
|
|
* g_task_return_int:
|
|
* @task: a #GTask.
|
|
* @result: the integer (#gssize) result of a task function.
|
|
*
|
|
* Sets @task's result to @result and completes the task (see
|
|
* g_task_return_pointer() for more discussion of exactly what this
|
|
* means).
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
void
|
|
g_task_return_int (GTask *task,
|
|
gssize result)
|
|
{
|
|
g_return_if_fail (task->result_set == FALSE);
|
|
|
|
task->result.size = result;
|
|
|
|
g_task_return (task, G_TASK_RETURN_SUCCESS);
|
|
}
|
|
|
|
/**
|
|
* g_task_propagate_int:
|
|
* @task: a #GTask.
|
|
* @error: return location for a #GError
|
|
*
|
|
* Gets the result of @task as an integer (#gssize).
|
|
*
|
|
* If the task resulted in an error, or was cancelled, then this will
|
|
* instead return -1 and set @error.
|
|
*
|
|
* Since this method transfers ownership of the return value (or
|
|
* error) to the caller, you may only call it once.
|
|
*
|
|
* Returns: the task result, or -1 on error
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
gssize
|
|
g_task_propagate_int (GTask *task,
|
|
GError **error)
|
|
{
|
|
if (g_task_propagate_error (task, error))
|
|
return -1;
|
|
|
|
g_return_val_if_fail (task->result_set == TRUE, -1);
|
|
|
|
task->result_set = FALSE;
|
|
return task->result.size;
|
|
}
|
|
|
|
/**
|
|
* g_task_return_boolean:
|
|
* @task: a #GTask.
|
|
* @result: the #gboolean result of a task function.
|
|
*
|
|
* Sets @task's result to @result and completes the task (see
|
|
* g_task_return_pointer() for more discussion of exactly what this
|
|
* means).
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
void
|
|
g_task_return_boolean (GTask *task,
|
|
gboolean result)
|
|
{
|
|
g_return_if_fail (task->result_set == FALSE);
|
|
|
|
task->result.boolean = result;
|
|
|
|
g_task_return (task, G_TASK_RETURN_SUCCESS);
|
|
}
|
|
|
|
/**
|
|
* g_task_propagate_boolean:
|
|
* @task: a #GTask.
|
|
* @error: return location for a #GError
|
|
*
|
|
* Gets the result of @task as a #gboolean.
|
|
*
|
|
* If the task resulted in an error, or was cancelled, then this will
|
|
* instead return %FALSE and set @error.
|
|
*
|
|
* Since this method transfers ownership of the return value (or
|
|
* error) to the caller, you may only call it once.
|
|
*
|
|
* Returns: the task result, or %FALSE on error
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
gboolean
|
|
g_task_propagate_boolean (GTask *task,
|
|
GError **error)
|
|
{
|
|
if (g_task_propagate_error (task, error))
|
|
return FALSE;
|
|
|
|
g_return_val_if_fail (task->result_set == TRUE, FALSE);
|
|
|
|
task->result_set = FALSE;
|
|
return task->result.boolean;
|
|
}
|
|
|
|
/**
|
|
* g_task_return_error:
|
|
* @task: a #GTask.
|
|
* @error: (transfer full): the #GError result of a task function.
|
|
*
|
|
* Sets @task's result to @error (which @task assumes ownership of)
|
|
* and completes the task (see g_task_return_pointer() for more
|
|
* discussion of exactly what this means).
|
|
*
|
|
* Note that since the task takes ownership of @error, and since the
|
|
* task may be completed before returning from g_task_return_error(),
|
|
* you cannot assume that @error is still valid after calling this.
|
|
* Call g_error_copy() on the error if you need to keep a local copy
|
|
* as well.
|
|
*
|
|
* See also g_task_return_new_error().
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
void
|
|
g_task_return_error (GTask *task,
|
|
GError *error)
|
|
{
|
|
g_return_if_fail (task->result_set == FALSE);
|
|
g_return_if_fail (error != NULL);
|
|
|
|
task->error = error;
|
|
|
|
g_task_return (task, G_TASK_RETURN_ERROR);
|
|
}
|
|
|
|
/**
|
|
* g_task_return_new_error:
|
|
* @task: a #GTask.
|
|
* @domain: a #GQuark.
|
|
* @code: an error code.
|
|
* @format: a string with format characters.
|
|
* @...: a list of values to insert into @format.
|
|
*
|
|
* Sets @task's result to a new #GError created from @domain, @code,
|
|
* @format, and the remaining arguments, and completes the task (see
|
|
* g_task_return_pointer() for more discussion of exactly what this
|
|
* means).
|
|
*
|
|
* See also g_task_return_error().
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
void
|
|
g_task_return_new_error (GTask *task,
|
|
GQuark domain,
|
|
gint code,
|
|
const char *format,
|
|
...)
|
|
{
|
|
GError *error;
|
|
va_list args;
|
|
|
|
va_start (args, format);
|
|
error = g_error_new_valist (domain, code, format, args);
|
|
va_end (args);
|
|
|
|
g_task_return_error (task, error);
|
|
}
|
|
|
|
/**
|
|
* g_task_return_error_if_cancelled:
|
|
* @task: a #GTask
|
|
*
|
|
* Checks if @task's #GCancellable has been cancelled, and if so, sets
|
|
* @task's error accordingly and completes the task (see
|
|
* g_task_return_pointer() for more discussion of exactly what this
|
|
* means).
|
|
*
|
|
* Return value: %TRUE if @task has been cancelled, %FALSE if not
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
gboolean
|
|
g_task_return_error_if_cancelled (GTask *task)
|
|
{
|
|
GError *error = NULL;
|
|
|
|
g_return_val_if_fail (task->result_set == FALSE, FALSE);
|
|
|
|
if (g_cancellable_set_error_if_cancelled (task->cancellable, &error))
|
|
{
|
|
/* We explicitly set task->error so this works even when
|
|
* check-cancellable is not set.
|
|
*/
|
|
g_clear_error (&task->error);
|
|
task->error = error;
|
|
|
|
g_task_return (task, G_TASK_RETURN_ERROR);
|
|
return TRUE;
|
|
}
|
|
else
|
|
return FALSE;
|
|
}
|
|
|
|
/**
|
|
* g_task_had_error:
|
|
* @task: a #GTask.
|
|
*
|
|
* Tests if @task resulted in an error.
|
|
*
|
|
* Returns: %TRUE if the task resulted in an error, %FALSE otherwise.
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
gboolean
|
|
g_task_had_error (GTask *task)
|
|
{
|
|
if (task->error != NULL)
|
|
return TRUE;
|
|
|
|
if (task->check_cancellable && g_cancellable_is_cancelled (task->cancellable))
|
|
return TRUE;
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
/**
|
|
* g_task_is_valid:
|
|
* @result: (type Gio.AsyncResult): A #GAsyncResult
|
|
* @source_object: (allow-none) (type GObject): the source object
|
|
* expected to be associated with the task
|
|
*
|
|
* Checks that @result is a #GTask, and that @source_object is its
|
|
* source object (or that @source_object is %NULL and @result has no
|
|
* source object). This can be used in g_return_if_fail() checks.
|
|
*
|
|
* Return value: %TRUE if @result and @source_object are valid, %FALSE
|
|
* if not
|
|
*
|
|
* Since: 2.36
|
|
*/
|
|
gboolean
|
|
g_task_is_valid (gpointer result,
|
|
gpointer source_object)
|
|
{
|
|
if (!G_IS_TASK (result))
|
|
return FALSE;
|
|
|
|
return G_TASK (result)->source_object == source_object;
|
|
}
|
|
|
|
static gint
|
|
g_task_compare_priority (gconstpointer a,
|
|
gconstpointer b,
|
|
gpointer user_data)
|
|
{
|
|
const GTask *ta = a;
|
|
const GTask *tb = b;
|
|
gboolean a_cancelled, b_cancelled;
|
|
|
|
/* Tasks that are causing other tasks to block have higher
|
|
* priority.
|
|
*/
|
|
if (ta->blocking_other_task && !tb->blocking_other_task)
|
|
return -1;
|
|
else if (tb->blocking_other_task && !ta->blocking_other_task)
|
|
return 1;
|
|
|
|
/* Let already-cancelled tasks finish right away */
|
|
a_cancelled = (ta->check_cancellable &&
|
|
g_cancellable_is_cancelled (ta->cancellable));
|
|
b_cancelled = (tb->check_cancellable &&
|
|
g_cancellable_is_cancelled (tb->cancellable));
|
|
if (a_cancelled && !b_cancelled)
|
|
return -1;
|
|
else if (b_cancelled && !a_cancelled)
|
|
return 1;
|
|
|
|
/* Lower priority == run sooner == negative return value */
|
|
return ta->priority - tb->priority;
|
|
}
|
|
|
|
static void
|
|
g_task_thread_pool_init (void)
|
|
{
|
|
task_pool = g_thread_pool_new (g_task_thread_pool_thread, NULL,
|
|
10, FALSE, NULL);
|
|
g_assert (task_pool != NULL);
|
|
|
|
g_thread_pool_set_sort_function (task_pool, g_task_compare_priority, NULL);
|
|
}
|
|
|
|
static void
|
|
g_task_thread_pool_resort (void)
|
|
{
|
|
g_thread_pool_set_sort_function (task_pool, g_task_compare_priority, NULL);
|
|
}
|
|
|
|
static void
|
|
g_task_class_init (GTaskClass *klass)
|
|
{
|
|
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
|
|
|
|
gobject_class->finalize = g_task_finalize;
|
|
}
|
|
|
|
static gpointer
|
|
g_task_get_user_data (GAsyncResult *res)
|
|
{
|
|
return G_TASK (res)->callback_data;
|
|
}
|
|
|
|
static gboolean
|
|
g_task_is_tagged (GAsyncResult *res,
|
|
gpointer source_tag)
|
|
{
|
|
return G_TASK (res)->source_tag == source_tag;
|
|
}
|
|
|
|
static void
|
|
g_task_async_result_iface_init (GAsyncResultIface *iface)
|
|
{
|
|
iface->get_user_data = g_task_get_user_data;
|
|
iface->get_source_object = g_task_ref_source_object;
|
|
iface->is_tagged = g_task_is_tagged;
|
|
}
|