gio/gfilemonitor.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, write to the
  17  * Free Software Foundation, Inc., 59 Temple Place, Suite 330,
  18  * Boston, MA 02111-1307, USA.
  19  *
  20  * Author: Alexander Larsson <alexl@redhat.com>
  21  */
  22
  23 #include "config.h"
  24 #include <string.h>
  25
  26 #include "gfilemonitor.h"
  27 #include "gioenumtypes.h"
  28 #include "gfile.h"
  29 #include "gvfs.h"
  30 #include "glibintl.h"
  31
  32
  33 struct _FileChange;
  34 typedef struct _FileChange FileChange;
  35 static void file_change_free (FileChange *change);
  36
  37 /**
  38  * SECTION:gfilemonitor
  39  * @short_description: File Monitor
  40  * @include: gio/gio.h
  41  *
  42  * Monitors a file or directory for changes.
  43  *
  44  * To obtain a #GFileMonitor for a file or directory, use
  45  * g_file_monitor(), g_file_monitor_file(), or
  46  * g_file_monitor_directory().
  47  *
  48  * To get informed about changes to the file or directory you are
  49  * monitoring, connect to the #GFileMonitor::changed signal. The
  50  * signal will be emitted in the <link
  51  * linkend="g-main-context-push-thread-default">thread-default main
  52  * context</link> of the thread that the monitor was created in
  53  * (though if the global default main context is blocked, this may
  54  * cause notifications to be blocked even if the thread-default
  55  * context is still running).
  56  **/
  57
  58 G_LOCK_DEFINE_STATIC(cancelled);
  59
  60 enum {
  61   CHANGED,
  62   LAST_SIGNAL
  63 };
  64
  65 /* work around a limitation of the aliasing foo */
  66 #undef g_file_monitor
  67
  68 G_DEFINE_ABSTRACT_TYPE (GFileMonitor, g_file_monitor, G_TYPE_OBJECT);
  69
  70 typedef struct {
  71   GFile *file;
  72   guint32 last_sent_change_time; /* 0 == not sent */
  73   guint32 send_delayed_change_at; /* 0 == never */
  74   guint32 send_virtual_changes_done_at; /* 0 == never */
  75 } RateLimiter;
  76
  77 struct _GFileMonitorPrivate {
  78   gboolean cancelled;
  79   int rate_limit_msec;
  80
  81   /* Rate limiting change events */
  82   GHashTable *rate_limiter;
  83
  84   GSource *pending_file_change_source;
  85   GSList *pending_file_changes; /* FileChange */
  86
  87   GSource *timeout;
  88   guint32 timeout_fires_at;
  89
  90   GMainContext *context;
  91 };
  92
  93 enum {
  94   PROP_0,
  95   PROP_RATE_LIMIT,
  96   PROP_CANCELLED
  97 };
  98
  99 static void
 100 g_file_monitor_set_property (GObject      *object,
 101                              guint         prop_id,
 102                              const GValue *value,
 103                              GParamSpec   *pspec)
 104 {
 105   GFileMonitor *monitor;
 106
 107   monitor = G_FILE_MONITOR (object);
 108
 109   switch (prop_id)
 110     {
 111     case PROP_RATE_LIMIT:
 112       g_file_monitor_set_rate_limit (monitor, g_value_get_int (value));
 113       break;
 114
 115     default:
 116       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 117       break;
 118     }
 119 }
 120
 121 static void
 122 g_file_monitor_get_property (GObject    *object,
 123                              guint       prop_id,
 124                              GValue     *value,
 125                              GParamSpec *pspec)
 126 {
 127   GFileMonitor *monitor;
 128   GFileMonitorPrivate *priv;
 129
 130   monitor = G_FILE_MONITOR (object);
 131   priv = monitor->priv;
 132
 133   switch (prop_id)
 134     {
 135     case PROP_RATE_LIMIT:
 136       g_value_set_int (value, priv->rate_limit_msec);
 137       break;
 138
 139     case PROP_CANCELLED:
 140       G_LOCK (cancelled);
 141       g_value_set_boolean (value, priv->cancelled);
 142       G_UNLOCK (cancelled);
 143       break;
 144
 145     default:
 146       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 147       break;
 148     }
 149 }
 150
 151 #define DEFAULT_RATE_LIMIT_MSECS 800
 152 #define DEFAULT_VIRTUAL_CHANGES_DONE_DELAY_SECS 2
 153
 154 static guint signals[LAST_SIGNAL] = { 0 };
 155
 156 static void
 157 rate_limiter_free (RateLimiter *limiter)
 158 {
 159   g_object_unref (limiter->file);
 160   g_slice_free (RateLimiter, limiter);
 161 }
 162
 163 static void
 164 g_file_monitor_finalize (GObject *object)
 165 {
 166   GFileMonitor *monitor;
 167
 168   monitor = G_FILE_MONITOR (object);
 169
 170   if (monitor->priv->timeout)
 171     {
 172       g_source_destroy (monitor->priv->timeout);
 173       g_source_unref (monitor->priv->timeout);
 174     }
 175
 176   g_hash_table_destroy (monitor->priv->rate_limiter);
 177
 178   g_main_context_unref (monitor->priv->context);
 179
 180   G_OBJECT_CLASS (g_file_monitor_parent_class)->finalize (object);
 181 }
 182
 183 static void
 184 g_file_monitor_dispose (GObject *object)
 185 {
 186   GFileMonitor *monitor;
 187   GFileMonitorPrivate *priv;
 188
 189   monitor = G_FILE_MONITOR (object);
 190   priv = monitor->priv;
 191
 192   if (priv->pending_file_change_source)
 193     {
 194       g_source_destroy (priv->pending_file_change_source);
 195       g_source_unref (priv->pending_file_change_source);
 196       priv->pending_file_change_source = NULL;
 197     }
 198   g_slist_free_full (priv->pending_file_changes, (GDestroyNotify) file_change_free);
 199   priv->pending_file_changes = NULL;
 200
 201   /* Make sure we cancel on last unref */
 202   g_file_monitor_cancel (monitor);
 203
 204   G_OBJECT_CLASS (g_file_monitor_parent_class)->dispose (object);
 205 }
 206
 207 static void
 208 g_file_monitor_class_init (GFileMonitorClass *klass)
 209 {
 210   GObjectClass *object_class;
 211
 212   g_type_class_add_private (klass, sizeof (GFileMonitorPrivate));
 213
 214   object_class = G_OBJECT_CLASS (klass);
 215   object_class->finalize = g_file_monitor_finalize;
 216   object_class->dispose = g_file_monitor_dispose;
 217   object_class->get_property = g_file_monitor_get_property;
 218   object_class->set_property = g_file_monitor_set_property;
 219
 220   /**
 221    * GFileMonitor::changed:
 222    * @monitor: a #GFileMonitor.
 223    * @file: a #GFile.
 224    * @other_file: (allow-none): a #GFile or #NULL.
 225    * @event_type: a #GFileMonitorEvent.
 226    *
 227    * Emitted when @file has been changed.
 228    *
 229    * If using #G_FILE_MONITOR_SEND_MOVED flag and @event_type is
 230    * #G_FILE_MONITOR_SEND_MOVED, @file will be set to a #GFile containing the
 231    * old path, and @other_file will be set to a #GFile containing the new path.
 232    *
 233    * In all the other cases, @other_file will be set to #NULL.
 234    **/
 235   signals[CHANGED] =
 236     g_signal_new (I_("changed"),
 237                   G_TYPE_FILE_MONITOR,
 238                   G_SIGNAL_RUN_LAST,
 239                   G_STRUCT_OFFSET (GFileMonitorClass, changed),
 240                   NULL, NULL,
 241                   NULL,
 242                   G_TYPE_NONE, 3,
 243                   G_TYPE_FILE, G_TYPE_FILE, G_TYPE_FILE_MONITOR_EVENT);
 244
 245   g_object_class_install_property (object_class,
 246                                    PROP_RATE_LIMIT,
 247                                    g_param_spec_int ("rate-limit",
 248                                                      P_("Rate limit"),
 249                                                      P_("The limit of the monitor to watch for changes, in milliseconds"),
 250                                                      0, G_MAXINT,
 251                                                      DEFAULT_RATE_LIMIT_MSECS,
 252                                                      G_PARAM_READWRITE|
 253                                                      G_PARAM_STATIC_NAME|G_PARAM_STATIC_NICK|G_PARAM_STATIC_BLURB));
 254
 255   g_object_class_install_property (object_class,
 256                                    PROP_CANCELLED,
 257                                    g_param_spec_boolean ("cancelled",
 258                                                          P_("Cancelled"),
 259                                                          P_("Whether the monitor has been cancelled"),
 260                                                          FALSE,
 261                                                          G_PARAM_READABLE|
 262                                                          G_PARAM_STATIC_NAME|G_PARAM_STATIC_NICK|G_PARAM_STATIC_BLURB));
 263 }
 264
 265 static void
 266 g_file_monitor_init (GFileMonitor *monitor)
 267 {
 268   monitor->priv = G_TYPE_INSTANCE_GET_PRIVATE (monitor,
 269                                                G_TYPE_FILE_MONITOR,
 270                                                GFileMonitorPrivate);
 271   monitor->priv->rate_limit_msec = DEFAULT_RATE_LIMIT_MSECS;
 272   monitor->priv->rate_limiter = g_hash_table_new_full (g_file_hash, (GEqualFunc)g_file_equal,
 273                                                        NULL, (GDestroyNotify) rate_limiter_free);
 274   monitor->priv->context = g_main_context_ref_thread_default ();
 275 }
 276
 277 /**
 278  * g_file_monitor_is_cancelled:
 279  * @monitor: a #GFileMonitor
 280  *
 281  * Returns whether the monitor is canceled.
 282  *
 283  * Returns: %TRUE if monitor is canceled. %FALSE otherwise.
 284  **/
 285 gboolean
 286 g_file_monitor_is_cancelled (GFileMonitor *monitor)
 287 {
 288   gboolean res;
 289
 290   g_return_val_if_fail (G_IS_FILE_MONITOR (monitor), FALSE);
 291
 292   G_LOCK (cancelled);
 293   res = monitor->priv->cancelled;
 294   G_UNLOCK (cancelled);
 295
 296   return res;
 297 }
 298
 299 /**
 300  * g_file_monitor_cancel:
 301  * @monitor: a #GFileMonitor.
 302  *
 303  * Cancels a file monitor.
 304  *
 305  * Returns: %TRUE if monitor was cancelled.
 306  **/
 307 gboolean
 308 g_file_monitor_cancel (GFileMonitor* monitor)
 309 {
 310   GFileMonitorClass *klass;
 311
 312   g_return_val_if_fail (G_IS_FILE_MONITOR (monitor), FALSE);
 313
 314   G_LOCK (cancelled);
 315   if (monitor->priv->cancelled)
 316     {
 317       G_UNLOCK (cancelled);
 318       return TRUE;
 319     }
 320
 321   monitor->priv->cancelled = TRUE;
 322   G_UNLOCK (cancelled);
 323
 324   g_object_notify (G_OBJECT (monitor), "cancelled");
 325
 326   klass = G_FILE_MONITOR_GET_CLASS (monitor);
 327   return (* klass->cancel) (monitor);
 328 }
 329
 330 /**
 331  * g_file_monitor_set_rate_limit:
 332  * @monitor: a #GFileMonitor.
 333  * @limit_msecs: a non-negative integer with the limit in milliseconds
 334  *     to poll for changes
 335  *
 336  * Sets the rate limit to which the @monitor will report
 337  * consecutive change events to the same file.
 338  */
 339 void
 340 g_file_monitor_set_rate_limit (GFileMonitor *monitor,
 341                                gint          limit_msecs)
 342 {
 343   GFileMonitorPrivate *priv;
 344
 345   g_return_if_fail (G_IS_FILE_MONITOR (monitor));
 346   g_return_if_fail (limit_msecs >= 0);
 347
 348   priv = monitor->priv;
 349   if (priv->rate_limit_msec != limit_msecs)
 350     {
 351       monitor->priv->rate_limit_msec = limit_msecs;
 352       g_object_notify (G_OBJECT (monitor), "rate-limit");
 353     }
 354 }
 355
 356 struct _FileChange {
 357   GFile             *child;
 358   GFile             *other_file;
 359   GFileMonitorEvent  event_type;
 360 };
 361
 362 static void
 363 file_change_free (FileChange *change)
 364 {
 365   g_object_unref (change->child);
 366   if (change->other_file)
 367     g_object_unref (change->other_file);
 368
 369   g_slice_free (FileChange, change);
 370 }
 371
 372 static gboolean
 373 emit_cb (gpointer data)
 374 {
 375   GFileMonitor *monitor = G_FILE_MONITOR (data);
 376   GSList *pending, *iter;
 377
 378   pending = g_slist_reverse (monitor->priv->pending_file_changes);
 379   monitor->priv->pending_file_changes = NULL;
 380   if (monitor->priv->pending_file_change_source)
 381     {
 382       g_source_unref (monitor->priv->pending_file_change_source);
 383       monitor->priv->pending_file_change_source = NULL;
 384     }
 385
 386   g_object_ref (monitor);
 387   for (iter = pending; iter; iter = iter->next)
 388     {
 389        FileChange *change = iter->data;
 390        g_signal_emit (monitor, signals[CHANGED], 0,
 391                       change->child, change->other_file, change->event_type);
 392        file_change_free (change);
 393     }
 394   g_slist_free (pending);
 395   g_object_unref (monitor);
 396
 397   return FALSE;
 398 }
 399
 400 static void
 401 emit_in_idle (GFileMonitor      *monitor,
 402               GFile             *child,
 403               GFile             *other_file,
 404               GFileMonitorEvent  event_type)
 405 {
 406   GSource *source;
 407   FileChange *change;
 408   GFileMonitorPrivate *priv;
 409
 410   priv = monitor->priv;
 411
 412   change = g_slice_new (FileChange);
 413
 414   change->child = g_object_ref (child);
 415   if (other_file)
 416     change->other_file = g_object_ref (other_file);
 417   else
 418     change->other_file = NULL;
 419   change->event_type = event_type;
 420
 421   if (!priv->pending_file_change_source)
 422     {
 423       source = g_idle_source_new ();
 424       priv->pending_file_change_source = source;
 425       g_source_set_priority (source, 0);
 426
 427       /* We don't ref monitor here - instead dispose will free any
 428        * pending idles.
 429        */
 430       g_source_set_callback (source, emit_cb, monitor, NULL);
 431       g_source_attach (source, monitor->priv->context);
 432     }
 433   /* We reverse this in the processor */
 434   priv->pending_file_changes = g_slist_prepend (priv->pending_file_changes, change);
 435 }
 436
 437 static guint32
 438 get_time_msecs (void)
 439 {
 440   return g_get_monotonic_time () / G_TIME_SPAN_MILLISECOND;
 441 }
 442
 443 static guint32
 444 time_difference (guint32 from, guint32 to)
 445 {
 446   if (from > to)
 447     return 0;
 448   return to - from;
 449 }
 450
 451 /* Change event rate limiting support: */
 452
 453 static RateLimiter *
 454 new_limiter (GFileMonitor *monitor,
 455              GFile             *file)
 456 {
 457   RateLimiter *limiter;
 458
 459   limiter = g_slice_new0 (RateLimiter);
 460   limiter->file = g_object_ref (file);
 461   g_hash_table_insert (monitor->priv->rate_limiter, file, limiter);
 462
 463   return limiter;
 464 }
 465
 466 static void
 467 rate_limiter_send_virtual_changes_done_now (GFileMonitor *monitor,
 468                                             RateLimiter  *limiter)
 469 {
 470   if (limiter->send_virtual_changes_done_at != 0)
 471     {
 472       emit_in_idle (monitor, limiter->file, NULL,
 473                     G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT);
 474       limiter->send_virtual_changes_done_at = 0;
 475     }
 476 }
 477
 478 static void
 479 rate_limiter_send_delayed_change_now (GFileMonitor *monitor,
 480                                       RateLimiter *limiter,
 481                                       guint32 time_now)
 482 {
 483   if (limiter->send_delayed_change_at != 0)
 484     {
 485       emit_in_idle (monitor,
 486                     limiter->file, NULL,
 487                     G_FILE_MONITOR_EVENT_CHANGED);
 488       limiter->send_delayed_change_at = 0;
 489       limiter->last_sent_change_time = time_now;
 490     }
 491 }
 492
 493 typedef struct {
 494   guint32 min_time;
 495   guint32 time_now;
 496   GFileMonitor *monitor;
 497 } ForEachData;
 498
 499 static gboolean
 500 calc_min_time (GFileMonitor *monitor,
 501                RateLimiter *limiter,
 502                guint32 time_now,
 503                guint32 *min_time)
 504 {
 505   gboolean delete_me;
 506   guint32 expire_at;
 507
 508   delete_me = TRUE;
 509
 510   if (limiter->last_sent_change_time != 0)
 511     {
 512       /* Set a timeout at 2*rate limit so that we can clear out the change from the hash eventually */
 513       expire_at = limiter->last_sent_change_time + 2 * monitor->priv->rate_limit_msec;
 514
 515       if (time_difference (time_now, expire_at) > 0)
 516         {
 517           delete_me = FALSE;
 518           *min_time = MIN (*min_time,
 519                            time_difference (time_now, expire_at));
 520         }
 521     }
 522
 523   if (limiter->send_delayed_change_at != 0)
 524     {
 525       delete_me = FALSE;
 526       *min_time = MIN (*min_time,
 527                        time_difference (time_now, limiter->send_delayed_change_at));
 528     }
 529
 530   if (limiter->send_virtual_changes_done_at != 0)
 531     {
 532       delete_me = FALSE;
 533       *min_time = MIN (*min_time,
 534                        time_difference (time_now, limiter->send_virtual_changes_done_at));
 535     }
 536
 537   return delete_me;
 538 }
 539
 540 static gboolean
 541 foreach_rate_limiter_fire (gpointer key,
 542                            gpointer value,
 543                            gpointer user_data)
 544 {
 545   RateLimiter *limiter = value;
 546   ForEachData *data = user_data;
 547
 548   if (limiter->send_delayed_change_at != 0 &&
 549       time_difference (data->time_now, limiter->send_delayed_change_at) == 0)
 550     rate_limiter_send_delayed_change_now (data->monitor, limiter, data->time_now);
 551
 552   if (limiter->send_virtual_changes_done_at != 0 &&
 553       time_difference (data->time_now, limiter->send_virtual_changes_done_at) == 0)
 554     rate_limiter_send_virtual_changes_done_now (data->monitor, limiter);
 555
 556   return calc_min_time (data->monitor, limiter, data->time_now, &data->min_time);
 557 }
 558
 559 static gboolean
 560 rate_limiter_timeout (gpointer timeout_data)
 561 {
 562   GFileMonitor *monitor = timeout_data;
 563   ForEachData data;
 564   GSource *source;
 565
 566   data.min_time = G_MAXUINT32;
 567   data.monitor = monitor;
 568   data.time_now = get_time_msecs ();
 569   g_hash_table_foreach_remove (monitor->priv->rate_limiter,
 570                                foreach_rate_limiter_fire,
 571                                &data);
 572
 573   /* Remove old timeout */
 574   if (monitor->priv->timeout)
 575     {
 576       g_source_destroy (monitor->priv->timeout);
 577       g_source_unref (monitor->priv->timeout);
 578       monitor->priv->timeout = NULL;
 579       monitor->priv->timeout_fires_at = 0;
 580     }
 581
 582   /* Set up new timeout */
 583   if (data.min_time != G_MAXUINT32)
 584     {
 585       source = g_timeout_source_new (data.min_time + 1); /* + 1 to make sure we've really passed the time */
 586       g_source_set_callback (source, rate_limiter_timeout, monitor, NULL);
 587       g_source_attach (source, monitor->priv->context);
 588
 589       monitor->priv->timeout = source;
 590       monitor->priv->timeout_fires_at = data.time_now + data.min_time;
 591     }
 592
 593   return FALSE;
 594 }
 595
 596 static gboolean
 597 foreach_rate_limiter_update (gpointer key,
 598                              gpointer value,
 599                              gpointer user_data)
 600 {
 601   RateLimiter *limiter = value;
 602   ForEachData *data = user_data;
 603
 604   return calc_min_time (data->monitor, limiter, data->time_now, &data->min_time);
 605 }
 606
 607 static void
 608 update_rate_limiter_timeout (GFileMonitor *monitor,
 609                              guint new_time)
 610 {
 611   ForEachData data;
 612   GSource *source;
 613
 614   if (monitor->priv->timeout_fires_at != 0 && new_time != 0 &&
 615       time_difference (new_time, monitor->priv->timeout_fires_at) == 0)
 616     return; /* Nothing to do, we already fire earlier than that */
 617
 618   data.min_time = G_MAXUINT32;
 619   data.monitor = monitor;
 620   data.time_now = get_time_msecs ();
 621   g_hash_table_foreach_remove (monitor->priv->rate_limiter,
 622                                foreach_rate_limiter_update,
 623                                &data);
 624
 625   /* Remove old timeout */
 626   if (monitor->priv->timeout)
 627     {
 628       g_source_destroy (monitor->priv->timeout);
 629       g_source_unref (monitor->priv->timeout);
 630       monitor->priv->timeout_fires_at = 0;
 631       monitor->priv->timeout = NULL;
 632     }
 633
 634   /* Set up new timeout */
 635   if (data.min_time != G_MAXUINT32)
 636     {
 637       source = g_timeout_source_new (data.min_time + 1);  /* + 1 to make sure we've really passed the time */
 638       g_source_set_callback (source, rate_limiter_timeout, monitor, NULL);
 639       g_source_attach (source, monitor->priv->context);
 640
 641       monitor->priv->timeout = source;
 642       monitor->priv->timeout_fires_at = data.time_now + data.min_time;
 643     }
 644 }
 645
 646 /**
 647  * g_file_monitor_emit_event:
 648  * @monitor: a #GFileMonitor.
 649  * @child: a #GFile.
 650  * @other_file: a #GFile.
 651  * @event_type: a set of #GFileMonitorEvent flags.
 652  *
 653  * Emits the #GFileMonitor::changed signal if a change
 654  * has taken place. Should be called from file monitor
 655  * implementations only.
 656  *
 657  * The signal will be emitted from an idle handler (in the <link
 658  * linkend="g-main-context-push-thread-default">thread-default main
 659  * context</link>).
 660  **/
 661 void
 662 g_file_monitor_emit_event (GFileMonitor      *monitor,
 663                            GFile             *child,
 664                            GFile             *other_file,
 665                            GFileMonitorEvent  event_type)
 666 {
 667   guint32 time_now, since_last;
 668   gboolean emit_now;
 669   RateLimiter *limiter;
 670
 671   g_return_if_fail (G_IS_FILE_MONITOR (monitor));
 672   g_return_if_fail (G_IS_FILE (child));
 673
 674   limiter = g_hash_table_lookup (monitor->priv->rate_limiter, child);
 675
 676   if (event_type != G_FILE_MONITOR_EVENT_CHANGED)
 677     {
 678       if (limiter)
 679         {
 680           rate_limiter_send_delayed_change_now (monitor, limiter, get_time_msecs ());
 681           if (event_type == G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT)
 682             limiter->send_virtual_changes_done_at = 0;
 683           else
 684             rate_limiter_send_virtual_changes_done_now (monitor, limiter);
 685           update_rate_limiter_timeout (monitor, 0);
 686         }
 687       emit_in_idle (monitor, child, other_file, event_type);
 688     }
 689   else
 690     {
 691       /* Changed event, rate limit */
 692       time_now = get_time_msecs ();
 693       emit_now = TRUE;
 694
 695       if (limiter)
 696         {
 697           since_last = time_difference (limiter->last_sent_change_time, time_now);
 698           if (since_last < monitor->priv->rate_limit_msec)
 699             {
 700               /* We ignore this change, but arm a timer so that we can fire it later if we
 701                  don't get any other events (that kill this timeout) */
 702               emit_now = FALSE;
 703               if (limiter->send_delayed_change_at == 0)
 704                 {
 705                   limiter->send_delayed_change_at = time_now + monitor->priv->rate_limit_msec;
 706                   update_rate_limiter_timeout (monitor, limiter->send_delayed_change_at);
 707                 }
 708             }
 709         }
 710
 711       if (limiter == NULL)
 712         limiter = new_limiter (monitor, child);
 713
 714       if (emit_now)
 715         {
 716           emit_in_idle (monitor, child, other_file, event_type);
 717
 718           limiter->last_sent_change_time = time_now;
 719           limiter->send_delayed_change_at = 0;
 720           /* Set a timeout of 2*rate limit so that we can clear out the change from the hash eventually */
 721           update_rate_limiter_timeout (monitor, time_now + 2 * monitor->priv->rate_limit_msec);
 722         }
 723
 724       /* Schedule a virtual change done. This is removed if we get a real one, and
 725          postponed if we get more change events. */
 726
 727       limiter->send_virtual_changes_done_at = time_now + DEFAULT_VIRTUAL_CHANGES_DONE_DELAY_SECS * 1000;
 728       update_rate_limiter_timeout (monitor, limiter->send_virtual_changes_done_at);
 729     }
 730 }