gio/gioscheduler.c

   1 /* GIO - GLib Input, Output and Streaming Library
   2  *
   3  * Copyright (C) 2006-2007 Red Hat, Inc.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General
  16  * Public License along with this library; if not, see <http://www.gnu.org/licenses/>.
  17  *
  18  * Author: Alexander Larsson <alexl@redhat.com>
  19  */
  20
  21 #include "config.h"
  22
  23 #include "gioscheduler.h"
  24 #include "gcancellable.h"
  25 #include "gtask.h"
  26
  27 /**
  28  * SECTION:gioscheduler
  29  * @short_description: I/O Scheduler
  30  * @include: gio/gio.h
  31  *
  32  * As of GLib 2.36, #GIOScheduler is deprecated in favor of
  33  * #GThreadPool and #GTask.
  34  *
  35  * Schedules asynchronous I/O operations. #GIOScheduler integrates
  36  * into the main event loop (#GMainLoop) and uses threads.
  37  */
  38
  39 struct _GIOSchedulerJob {
  40   GList *active_link;
  41   GTask *task;
  42
  43   GIOSchedulerJobFunc job_func;
  44   gpointer data;
  45   GDestroyNotify destroy_notify;
  46
  47   GCancellable *cancellable;
  48   gulong cancellable_id;
  49   GMainContext *context;
  50 };
  51
  52 G_LOCK_DEFINE_STATIC(active_jobs);
  53 static GList *active_jobs = NULL;
  54
  55 static void
  56 g_io_job_free (GIOSchedulerJob *job)
  57 {
  58   if (job->destroy_notify)
  59     job->destroy_notify (job->data);
  60
  61   G_LOCK (active_jobs);
  62   active_jobs = g_list_delete_link (active_jobs, job->active_link);
  63   G_UNLOCK (active_jobs);
  64
  65   if (job->cancellable)
  66     g_object_unref (job->cancellable);
  67   g_main_context_unref (job->context);
  68   g_slice_free (GIOSchedulerJob, job);
  69 }
  70
  71 static void
  72 io_job_thread (GTask         *task,
  73                gpointer       source_object,
  74                gpointer       task_data,
  75                GCancellable  *cancellable)
  76 {
  77   GIOSchedulerJob *job = task_data;
  78   gboolean result;
  79
  80   if (job->cancellable)
  81     g_cancellable_push_current (job->cancellable);
  82
  83   do
  84     {
  85       result = job->job_func (job, job->cancellable, job->data);
  86     }
  87   while (result);
  88
  89   if (job->cancellable)
  90     g_cancellable_pop_current (job->cancellable);
  91 }
  92
  93 /**
  94  * g_io_scheduler_push_job:
  95  * @job_func: a #GIOSchedulerJobFunc.
  96  * @user_data: data to pass to @job_func
  97  * @notify: (nullable): a #GDestroyNotify for @user_data, or %NULL
  98  * @io_priority: the [I/O priority][io-priority]
  99  * of the request.
 100  * @cancellable: optional #GCancellable object, %NULL to ignore.
 101  *
 102  * Schedules the I/O job to run in another thread.
 103  *
 104  * @notify will be called on @user_data after @job_func has returned,
 105  * regardless whether the job was cancelled or has run to completion.
 106  *
 107  * If @cancellable is not %NULL, it can be used to cancel the I/O job
 108  * by calling g_cancellable_cancel() or by calling
 109  * g_io_scheduler_cancel_all_jobs().
 110  *
 111  * Deprecated: use #GThreadPool or g_task_run_in_thread()
 112  **/
 113 void
 114 g_io_scheduler_push_job (GIOSchedulerJobFunc  job_func,
 115                          gpointer             user_data,
 116                          GDestroyNotify       notify,
 117                          gint                 io_priority,
 118                          GCancellable        *cancellable)
 119 {
 120   GIOSchedulerJob *job;
 121   GTask *task;
 122
 123   g_return_if_fail (job_func != NULL);
 124
 125   job = g_slice_new0 (GIOSchedulerJob);
 126   job->job_func = job_func;
 127   job->data = user_data;
 128   job->destroy_notify = notify;
 129
 130   if (cancellable)
 131     job->cancellable = g_object_ref (cancellable);
 132
 133   job->context = g_main_context_ref_thread_default ();
 134
 135   G_LOCK (active_jobs);
 136   active_jobs = g_list_prepend (active_jobs, job);
 137   job->active_link = active_jobs;
 138   G_UNLOCK (active_jobs);
 139
 140   task = g_task_new (NULL, cancellable, NULL, NULL);
 141 G_GNUC_BEGIN_IGNORE_DEPRECATIONS
 142   g_task_set_source_tag (task, g_io_scheduler_push_job);
 143 G_GNUC_END_IGNORE_DEPRECATIONS
 144   g_task_set_task_data (task, job, (GDestroyNotify)g_io_job_free);
 145   g_task_set_priority (task, io_priority);
 146   g_task_run_in_thread (task, io_job_thread);
 147   g_object_unref (task);
 148 }
 149
 150 /**
 151  * g_io_scheduler_cancel_all_jobs:
 152  *
 153  * Cancels all cancellable I/O jobs.
 154  *
 155  * A job is cancellable if a #GCancellable was passed into
 156  * g_io_scheduler_push_job().
 157  *
 158  * Deprecated: You should never call this function, since you don't
 159  * know how other libraries in your program might be making use of
 160  * gioscheduler.
 161  **/
 162 void
 163 g_io_scheduler_cancel_all_jobs (void)
 164 {
 165   GList *cancellable_list, *l;
 166
 167   G_LOCK (active_jobs);
 168   cancellable_list = NULL;
 169   for (l = active_jobs; l != NULL; l = l->next)
 170     {
 171       GIOSchedulerJob *job = l->data;
 172       if (job->cancellable)
 173         cancellable_list = g_list_prepend (cancellable_list,
 174                                            g_object_ref (job->cancellable));
 175     }
 176   G_UNLOCK (active_jobs);
 177
 178   for (l = cancellable_list; l != NULL; l = l->next)
 179     {
 180       GCancellable *c = l->data;
 181       g_cancellable_cancel (c);
 182       g_object_unref (c);
 183     }
 184   g_list_free (cancellable_list);
 185 }
 186
 187 typedef struct {
 188   GSourceFunc func;
 189   gboolean ret_val;
 190   gpointer data;
 191   GDestroyNotify notify;
 192
 193   GMutex ack_lock;
 194   GCond ack_condition;
 195   gboolean ack;
 196 } MainLoopProxy;
 197
 198 static gboolean
 199 mainloop_proxy_func (gpointer data)
 200 {
 201   MainLoopProxy *proxy = data;
 202
 203   proxy->ret_val = proxy->func (proxy->data);
 204
 205   if (proxy->notify)
 206     proxy->notify (proxy->data);
 207
 208   g_mutex_lock (&proxy->ack_lock);
 209   proxy->ack = TRUE;
 210   g_cond_signal (&proxy->ack_condition);
 211   g_mutex_unlock (&proxy->ack_lock);
 212
 213   return FALSE;
 214 }
 215
 216 static void
 217 mainloop_proxy_free (MainLoopProxy *proxy)
 218 {
 219   g_mutex_clear (&proxy->ack_lock);
 220   g_cond_clear (&proxy->ack_condition);
 221   g_free (proxy);
 222 }
 223
 224 /**
 225  * g_io_scheduler_job_send_to_mainloop:
 226  * @job: a #GIOSchedulerJob
 227  * @func: a #GSourceFunc callback that will be called in the original thread
 228  * @user_data: data to pass to @func
 229  * @notify: (nullable): a #GDestroyNotify for @user_data, or %NULL
 230  *
 231  * Used from an I/O job to send a callback to be run in the thread
 232  * that the job was started from, waiting for the result (and thus
 233  * blocking the I/O job).
 234  *
 235  * Returns: The return value of @func
 236  *
 237  * Deprecated: Use g_main_context_invoke().
 238  **/
 239 gboolean
 240 g_io_scheduler_job_send_to_mainloop (GIOSchedulerJob *job,
 241                                      GSourceFunc      func,
 242                                      gpointer         user_data,
 243                                      GDestroyNotify   notify)
 244 {
 245   GSource *source;
 246   MainLoopProxy *proxy;
 247   gboolean ret_val;
 248
 249   g_return_val_if_fail (job != NULL, FALSE);
 250   g_return_val_if_fail (func != NULL, FALSE);
 251
 252   proxy = g_new0 (MainLoopProxy, 1);
 253   proxy->func = func;
 254   proxy->data = user_data;
 255   proxy->notify = notify;
 256   g_mutex_init (&proxy->ack_lock);
 257   g_cond_init (&proxy->ack_condition);
 258   g_mutex_lock (&proxy->ack_lock);
 259
 260   source = g_idle_source_new ();
 261   g_source_set_priority (source, G_PRIORITY_DEFAULT);
 262   g_source_set_callback (source, mainloop_proxy_func, proxy,
 263                          NULL);
 264   g_source_set_name (source, "[gio] mainloop_proxy_func");
 265
 266   g_source_attach (source, job->context);
 267   g_source_unref (source);
 268
 269   while (!proxy->ack)
 270     g_cond_wait (&proxy->ack_condition, &proxy->ack_lock);
 271   g_mutex_unlock (&proxy->ack_lock);
 272
 273   ret_val = proxy->ret_val;
 274   mainloop_proxy_free (proxy);
 275
 276   return ret_val;
 277 }
 278
 279 /**
 280  * g_io_scheduler_job_send_to_mainloop_async:
 281  * @job: a #GIOSchedulerJob
 282  * @func: a #GSourceFunc callback that will be called in the original thread
 283  * @user_data: data to pass to @func
 284  * @notify: (nullable): a #GDestroyNotify for @user_data, or %NULL
 285  *
 286  * Used from an I/O job to send a callback to be run asynchronously in
 287  * the thread that the job was started from. The callback will be run
 288  * when the main loop is available, but at that time the I/O job might
 289  * have finished. The return value from the callback is ignored.
 290  *
 291  * Note that if you are passing the @user_data from g_io_scheduler_push_job()
 292  * on to this function you have to ensure that it is not freed before
 293  * @func is called, either by passing %NULL as @notify to
 294  * g_io_scheduler_push_job() or by using refcounting for @user_data.
 295  *
 296  * Deprecated: Use g_main_context_invoke().
 297  **/
 298 void
 299 g_io_scheduler_job_send_to_mainloop_async (GIOSchedulerJob *job,
 300                                            GSourceFunc      func,
 301                                            gpointer         user_data,
 302                                            GDestroyNotify   notify)
 303 {
 304   GSource *source;
 305   MainLoopProxy *proxy;
 306
 307   g_return_if_fail (job != NULL);
 308   g_return_if_fail (func != NULL);
 309
 310   proxy = g_new0 (MainLoopProxy, 1);
 311   proxy->func = func;
 312   proxy->data = user_data;
 313   proxy->notify = notify;
 314   g_mutex_init (&proxy->ack_lock);
 315   g_cond_init (&proxy->ack_condition);
 316
 317   source = g_idle_source_new ();
 318   g_source_set_priority (source, G_PRIORITY_DEFAULT);
 319   g_source_set_callback (source, mainloop_proxy_func, proxy,
 320                          (GDestroyNotify)mainloop_proxy_free);
 321   g_source_set_name (source, "[gio] mainloop_proxy_func");
 322
 323   g_source_attach (source, job->context);
 324   g_source_unref (source);
 325 }