gio/gdirectorymonitor.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 "gdirectorymonitor.h"
  27 #include "gio-marshal.h"
  28 #include "gfile.h"
  29 #include "gvfs.h"
  30 #include "glibintl.h"
  31
  32 #include "gioalias.h"
  33
  34 /**
  35  * SECTION:gdirectorymonitor
  36  * @short_description: Directory Monitor
  37  * @see_also: #GFileMonitor
  38  *
  39  * Monitors a directory for changes to files in it.
  40  *
  41  **/
  42
  43 enum {
  44   CHANGED,
  45   LAST_SIGNAL
  46 };
  47
  48 G_DEFINE_ABSTRACT_TYPE (GDirectoryMonitor, g_directory_monitor, G_TYPE_OBJECT);
  49
  50 typedef struct {
  51   GFile *file;
  52   guint32 last_sent_change_time; /* 0 == not sent */
  53   guint32 send_delayed_change_at; /* 0 == never */
  54   guint32 send_virtual_changes_done_at; /* 0 == never */
  55 } RateLimiter;
  56
  57 struct _GDirectoryMonitorPrivate {
  58   gboolean cancelled;
  59   int rate_limit_msec;
  60
  61   GHashTable *rate_limiter;
  62
  63   GSource *timeout;
  64   guint32 timeout_fires_at;
  65 };
  66
  67 enum {
  68   PROP_0,
  69   PROP_RATE_LIMIT,
  70   PROP_CANCELLED
  71 };
  72
  73 #define DEFAULT_RATE_LIMIT_MSECS 800
  74 #define DEFAULT_VIRTUAL_CHANGES_DONE_DELAY_SECS 2
  75
  76 static guint signals[LAST_SIGNAL] = { 0 };
  77
  78 static void
  79 rate_limiter_free (RateLimiter *limiter)
  80 {
  81   g_object_unref (limiter->file);
  82   g_free (limiter);
  83 }
  84
  85 static void
  86 g_directory_monitor_set_property (GObject      *object,
  87                                   guint         prop_id,
  88                                   const GValue *value,
  89                                   GParamSpec   *pspec)
  90 {
  91   GDirectoryMonitor *monitor;
  92
  93   monitor = G_DIRECTORY_MONITOR (object);
  94
  95   switch (prop_id)
  96     {
  97     case PROP_RATE_LIMIT:
  98       g_directory_monitor_set_rate_limit (monitor, g_value_get_int (value));
  99       break;
 100
 101     default:
 102       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 103       break;
 104     }
 105 }
 106
 107 static void
 108 g_directory_monitor_get_property (GObject    *object,
 109                                   guint       prop_id,
 110                                   GValue     *value,
 111                                   GParamSpec *pspec)
 112 {
 113   GDirectoryMonitor *monitor;
 114   GDirectoryMonitorPrivate *priv;
 115
 116   monitor = G_DIRECTORY_MONITOR (object);
 117   priv = monitor->priv;
 118
 119   switch (prop_id)
 120     {
 121     case PROP_RATE_LIMIT:
 122       g_value_set_int (value, priv->rate_limit_msec);
 123       break;
 124
 125     case PROP_CANCELLED:
 126       g_value_set_boolean (value, priv->cancelled);
 127       break;
 128
 129     default:
 130       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
 131       break;
 132     }
 133 }
 134
 135 static void
 136 g_directory_monitor_finalize (GObject *object)
 137 {
 138   GDirectoryMonitor *monitor;
 139
 140   monitor = G_DIRECTORY_MONITOR (object);
 141
 142   if (monitor->priv->timeout)
 143     {
 144       g_source_destroy (monitor->priv->timeout);
 145       g_source_unref (monitor->priv->timeout);
 146     }
 147
 148   g_hash_table_destroy (monitor->priv->rate_limiter);
 149
 150   if (G_OBJECT_CLASS (g_directory_monitor_parent_class)->finalize)
 151     (*G_OBJECT_CLASS (g_directory_monitor_parent_class)->finalize) (object);
 152 }
 153
 154 static void
 155 g_directory_monitor_dispose (GObject *object)
 156 {
 157   GDirectoryMonitor *monitor;
 158
 159   monitor = G_DIRECTORY_MONITOR (object);
 160
 161   /* Make sure we cancel on last unref */
 162   if (!monitor->priv->cancelled)
 163     g_directory_monitor_cancel (monitor);
 164
 165   if (G_OBJECT_CLASS (g_directory_monitor_parent_class)->dispose)
 166     (*G_OBJECT_CLASS (g_directory_monitor_parent_class)->dispose) (object);
 167 }
 168
 169 static void
 170 g_directory_monitor_class_init (GDirectoryMonitorClass *klass)
 171 {
 172   GObjectClass *object_class;
 173
 174   g_type_class_add_private (klass, sizeof (GDirectoryMonitorPrivate));
 175
 176   object_class = G_OBJECT_CLASS (klass);
 177   object_class->finalize = g_directory_monitor_finalize;
 178   object_class->dispose = g_directory_monitor_dispose;
 179   object_class->get_property = g_directory_monitor_get_property;
 180   object_class->set_property = g_directory_monitor_set_property;
 181
 182   /**
 183    * GDirectoryMonitor::changed:
 184    * @monitor: the #GDirectoryMonitor
 185    * @child: the #GFile which changed
 186    * @other_file: the other #GFile which changed
 187    * @event_type: a #GFileMonitorEvent indicating what the event was
 188    *
 189    * Emitted when a child file changes.
 190    */
 191   signals[CHANGED] =
 192     g_signal_new (I_("changed"),
 193                   G_TYPE_DIRECTORY_MONITOR,
 194                   G_SIGNAL_RUN_LAST,
 195                   G_STRUCT_OFFSET (GDirectoryMonitorClass, changed),
 196                   NULL, NULL,
 197                   _gio_marshal_VOID__OBJECT_OBJECT_INT,
 198                   G_TYPE_NONE, 3,
 199                   G_TYPE_FILE, G_TYPE_FILE, G_TYPE_INT);
 200
 201   g_object_class_install_property (object_class,
 202                                    PROP_RATE_LIMIT,
 203                                    g_param_spec_int ("rate-limit",
 204                                                      P_("Rate limit"),
 205                                                      P_("The limit of the monitor to watch for changes, in milliseconds"),
 206                                                      0, G_MAXINT,
 207                                                      DEFAULT_RATE_LIMIT_MSECS,
 208                                                      G_PARAM_READWRITE|
 209                                                      G_PARAM_STATIC_NAME|G_PARAM_STATIC_NICK|G_PARAM_STATIC_BLURB));
 210
 211   g_object_class_install_property (object_class,
 212                                    PROP_CANCELLED,
 213                                    g_param_spec_boolean ("cancelled",
 214                                                          P_("Cancelled"),
 215                                                          P_("Whether the monitor has been cancelled"),
 216                                                          FALSE,
 217                                                          G_PARAM_READABLE|
 218                                                          G_PARAM_STATIC_NAME|G_PARAM_STATIC_NICK|G_PARAM_STATIC_BLURB));
 219
 220 }
 221
 222 static void
 223 g_directory_monitor_init (GDirectoryMonitor *monitor)
 224 {
 225   monitor->priv = G_TYPE_INSTANCE_GET_PRIVATE (monitor,
 226                                                G_TYPE_DIRECTORY_MONITOR,
 227                                                GDirectoryMonitorPrivate);
 228
 229   monitor->priv->rate_limit_msec = DEFAULT_RATE_LIMIT_MSECS;
 230   monitor->priv->rate_limiter = g_hash_table_new_full (g_file_hash, (GEqualFunc)g_file_equal,
 231                                                        NULL, (GDestroyNotify) rate_limiter_free);
 232 }
 233
 234
 235 /**
 236  * g_directory_monitor_cancel:
 237  * @monitor: a #GDirectoryMonitor.
 238  *
 239  * Cancels the monitoring activity on @monitor. Note that
 240  * the monitor is automatically cancelled when finalized.
 241  *
 242  * It is safe to call this multiple times.
 243  *
 244  * Returns: %TRUE if the monitor was cancelled successfully. %FALSE otherwise.
 245  **/
 246 gboolean
 247 g_directory_monitor_cancel (GDirectoryMonitor *monitor)
 248 {
 249   GDirectoryMonitorClass *class;
 250
 251   g_return_val_if_fail (G_IS_DIRECTORY_MONITOR (monitor), FALSE);
 252
 253   if (monitor->priv->cancelled)
 254     return TRUE;
 255
 256   monitor->priv->cancelled = TRUE;
 257   g_object_notify (G_OBJECT (monitor), "cancelled");
 258
 259   class = G_DIRECTORY_MONITOR_GET_CLASS (monitor);
 260   return (* class->cancel) (monitor);
 261 }
 262
 263 /**
 264  * g_directory_monitor_set_rate_limit:
 265  * @monitor: a #GDirectoryMonitor.
 266  * @limit_msecs: the change rate limit of the directory monitor in milliseconds.
 267  *
 268  * Report same consecutive changes of the same type at most once each @limit_msecs milliseconds.
 269  **/
 270 void
 271 g_directory_monitor_set_rate_limit (GDirectoryMonitor *monitor,
 272                                     int                limit_msecs)
 273 {
 274   GDirectoryMonitorPrivate *priv;
 275   g_return_if_fail (G_IS_DIRECTORY_MONITOR (monitor));
 276   priv = monitor->priv;
 277   if (priv->rate_limit_msec != limit_msecs)
 278     {
 279       monitor->priv->rate_limit_msec = limit_msecs;
 280       g_object_notify (G_OBJECT (monitor), "rate-limit");
 281     }
 282 }
 283
 284 /**
 285  * g_directory_monitor_is_cancelled:
 286  * @monitor: a #GDirectoryMonitor.
 287  *
 288  * Checks whether @monitor is cancelled.
 289  *
 290  * Returns: %TRUE if the monitor on the directory was cancelled.
 291  *     %FALSE otherwise.
 292  **/
 293 gboolean
 294 g_directory_monitor_is_cancelled (GDirectoryMonitor *monitor)
 295 {
 296   g_return_val_if_fail (G_IS_DIRECTORY_MONITOR (monitor), FALSE);
 297
 298   return monitor->priv->cancelled;
 299 }
 300
 301 static guint32
 302 get_time_msecs (void)
 303 {
 304   return g_thread_gettime() / (1000 * 1000);
 305 }
 306
 307 static guint32
 308 time_difference (guint32 from, guint32 to)
 309 {
 310   if (from > to)
 311     return 0;
 312   return to - from;
 313 }
 314
 315 static RateLimiter *
 316 new_limiter (GDirectoryMonitor *monitor,
 317              GFile             *file)
 318 {
 319   RateLimiter *limiter;
 320
 321   limiter = g_new0 (RateLimiter, 1);
 322   limiter->file = g_object_ref (file);
 323   g_hash_table_insert (monitor->priv->rate_limiter, file, limiter);
 324
 325   return limiter;
 326 }
 327
 328 static void
 329 rate_limiter_send_virtual_changes_done_now (GDirectoryMonitor *monitor,
 330                                             RateLimiter       *limiter)
 331 {
 332   if (limiter->send_virtual_changes_done_at != 0)
 333     {
 334       g_signal_emit (monitor, signals[CHANGED], 0, limiter->file, NULL, G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT);
 335       limiter->send_virtual_changes_done_at = 0;
 336     }
 337 }
 338
 339 static void
 340 rate_limiter_send_delayed_change_now (GDirectoryMonitor *monitor,
 341                                       RateLimiter       *limiter,
 342                                       guint32            time_now)
 343 {
 344   if (limiter->send_delayed_change_at != 0)
 345     {
 346       g_signal_emit (monitor, signals[CHANGED], 0, limiter->file, NULL, G_FILE_MONITOR_EVENT_CHANGED);
 347       limiter->send_delayed_change_at = 0;
 348       limiter->last_sent_change_time = time_now;
 349     }
 350 }
 351
 352 typedef struct {
 353   guint32 min_time;
 354   guint32 time_now;
 355   GDirectoryMonitor *monitor;
 356 } ForEachData;
 357
 358 static gboolean
 359 calc_min_time (GDirectoryMonitor *monitor,
 360                RateLimiter       *limiter,
 361                guint32            time_now,
 362                guint32           *min_time)
 363 {
 364   gboolean delete_me;
 365   guint32 expire_at;
 366
 367   delete_me = TRUE;
 368
 369   if (limiter->last_sent_change_time != 0)
 370     {
 371       /* Set a timeout at 2*rate limit so that we can clear out the change from the hash eventualy */
 372       expire_at = limiter->last_sent_change_time + 2 * monitor->priv->rate_limit_msec;
 373
 374       if (time_difference (time_now, expire_at) > 0)
 375         {
 376           delete_me = FALSE;
 377           *min_time = MIN (*min_time,
 378                            time_difference (time_now, expire_at));
 379         }
 380     }
 381
 382   if (limiter->send_delayed_change_at != 0)
 383     {
 384       delete_me = FALSE;
 385       *min_time = MIN (*min_time,
 386                        time_difference (time_now, limiter->send_delayed_change_at));
 387     }
 388
 389   if (limiter->send_virtual_changes_done_at != 0)
 390     {
 391       delete_me = FALSE;
 392       *min_time = MIN (*min_time,
 393                        time_difference (time_now, limiter->send_virtual_changes_done_at));
 394     }
 395
 396   return delete_me;
 397 }
 398
 399 static gboolean
 400 foreach_rate_limiter_fire (gpointer key,
 401                            gpointer value,
 402                            gpointer user_data)
 403 {
 404   RateLimiter *limiter = value;
 405   ForEachData *data = user_data;
 406
 407   if (limiter->send_delayed_change_at != 0 &&
 408       time_difference (data->time_now, limiter->send_delayed_change_at) == 0)
 409     rate_limiter_send_delayed_change_now (data->monitor, limiter, data->time_now);
 410
 411   if (limiter->send_virtual_changes_done_at != 0 &&
 412       time_difference (data->time_now, limiter->send_virtual_changes_done_at) == 0)
 413     rate_limiter_send_virtual_changes_done_now (data->monitor, limiter);
 414
 415   return calc_min_time (data->monitor, limiter, data->time_now, &data->min_time);
 416 }
 417
 418 static gboolean
 419 rate_limiter_timeout (gpointer timeout_data)
 420 {
 421   GDirectoryMonitor *monitor = timeout_data;
 422   ForEachData data;
 423   GSource *source;
 424
 425   data.min_time = G_MAXUINT32;
 426   data.monitor = monitor;
 427   data.time_now = get_time_msecs ();
 428   g_hash_table_foreach_remove (monitor->priv->rate_limiter,
 429                                foreach_rate_limiter_fire,
 430                                &data);
 431
 432   /* Remove old timeout */
 433   if (monitor->priv->timeout)
 434     {
 435       g_source_destroy (monitor->priv->timeout);
 436       g_source_unref (monitor->priv->timeout);
 437       monitor->priv->timeout = NULL;
 438       monitor->priv->timeout_fires_at = 0;
 439     }
 440
 441   /* Set up new timeout */
 442   if (data.min_time != G_MAXUINT32)
 443     {
 444       source = g_timeout_source_new (data.min_time + 1); /* + 1 to make sure we've really passed the time */
 445       g_source_set_callback (source, rate_limiter_timeout, monitor, NULL);
 446       g_source_attach (source, NULL);
 447
 448       monitor->priv->timeout = source;
 449       monitor->priv->timeout_fires_at = data.time_now + data.min_time;
 450     }
 451
 452   return FALSE;
 453 }
 454
 455 static gboolean
 456 foreach_rate_limiter_update (gpointer key,
 457                              gpointer value,
 458                              gpointer user_data)
 459 {
 460   RateLimiter *limiter = value;
 461   ForEachData *data = user_data;
 462
 463   return calc_min_time (data->monitor, limiter, data->time_now, &data->min_time);
 464 }
 465
 466 static void
 467 update_rate_limiter_timeout (GDirectoryMonitor *monitor,
 468                              guint              new_time)
 469 {
 470   ForEachData data;
 471   GSource *source;
 472
 473   if (monitor->priv->timeout_fires_at != 0 && new_time != 0 &&
 474       time_difference (new_time, monitor->priv->timeout_fires_at) == 0)
 475     return; /* Nothing to do, we already fire earlier than that */
 476
 477   data.min_time = G_MAXUINT32;
 478   data.monitor = monitor;
 479   data.time_now = get_time_msecs ();
 480   g_hash_table_foreach_remove (monitor->priv->rate_limiter,
 481                                foreach_rate_limiter_update,
 482                                &data);
 483
 484   /* Remove old timeout */
 485   if (monitor->priv->timeout)
 486     {
 487       g_source_destroy (monitor->priv->timeout);
 488       g_source_unref (monitor->priv->timeout);
 489       monitor->priv->timeout_fires_at = 0;
 490       monitor->priv->timeout = NULL;
 491     }
 492
 493   /* Set up new timeout */
 494   if (data.min_time != G_MAXUINT32)
 495     {
 496       source = g_timeout_source_new (data.min_time + 1);  /* + 1 to make sure we've really passed the time */
 497       g_source_set_callback (source, rate_limiter_timeout, monitor, NULL);
 498       g_source_attach (source, NULL);
 499
 500       monitor->priv->timeout = source;
 501       monitor->priv->timeout_fires_at = data.time_now + data.min_time;
 502     }
 503 }
 504
 505 /**
 506  * g_directory_monitor_emit_event:
 507  * @monitor: a #GDirectoryMonitor.
 508  * @child: a #GFile.
 509  * @other_file: a #GFile.
 510  * @event_type: a set of #GFileMonitorEvent flags.
 511  *
 512  * Emits the #GDirectoryMonitor::changed signal if a change
 513  * has taken place. Should be called from directory monitor
 514  * implementations only.
 515  **/
 516 void
 517 g_directory_monitor_emit_event (GDirectoryMonitor *monitor,
 518                                 GFile             *child,
 519                                 GFile             *other_file,
 520                                 GFileMonitorEvent  event_type)
 521 {
 522   guint32 time_now, since_last;
 523   gboolean emit_now;
 524   RateLimiter *limiter;
 525
 526   g_return_if_fail (G_IS_DIRECTORY_MONITOR (monitor));
 527   g_return_if_fail (G_IS_FILE (child));
 528
 529   limiter = g_hash_table_lookup (monitor->priv->rate_limiter, child);
 530
 531   if (event_type != G_FILE_MONITOR_EVENT_CHANGED)
 532     {
 533       if (limiter)
 534         {
 535           rate_limiter_send_delayed_change_now (monitor, limiter, get_time_msecs ());
 536           if (event_type == G_FILE_MONITOR_EVENT_CHANGES_DONE_HINT)
 537             limiter->send_virtual_changes_done_at = 0;
 538           else
 539             rate_limiter_send_virtual_changes_done_now (monitor, limiter);
 540           update_rate_limiter_timeout (monitor, 0);
 541         }
 542       g_signal_emit (monitor, signals[CHANGED], 0, child, other_file, event_type);
 543     }
 544   else
 545     {
 546       /* Changed event, rate limit */
 547       time_now = get_time_msecs ();
 548       emit_now = TRUE;
 549
 550       if (limiter)
 551         {
 552           since_last = time_difference (limiter->last_sent_change_time, time_now);
 553           if (since_last < monitor->priv->rate_limit_msec)
 554             {
 555               /* We ignore this change, but arm a timer so that we can fire it later if we
 556                  don't get any other events (that kill this timeout) */
 557               emit_now = FALSE;
 558               if (limiter->send_delayed_change_at == 0)
 559                 {
 560                   limiter->send_delayed_change_at = time_now + monitor->priv->rate_limit_msec;
 561                   update_rate_limiter_timeout (monitor, limiter->send_delayed_change_at);
 562                 }
 563             }
 564         }
 565
 566       if (limiter == NULL)
 567         limiter = new_limiter (monitor, child);
 568
 569       if (emit_now)
 570         {
 571           g_signal_emit (monitor, signals[CHANGED], 0, child, other_file, event_type);
 572
 573           limiter->last_sent_change_time = time_now;
 574           limiter->send_delayed_change_at = 0;
 575           /* Set a timeout of 2*rate limit so that we can clear out the change from the hash eventualy */
 576           update_rate_limiter_timeout (monitor, time_now + 2 * monitor->priv->rate_limit_msec);
 577         }
 578
 579       /* Schedule a virtual change done. This is removed if we get a real one, and
 580          postponed if we get more change events. */
 581
 582       limiter->send_virtual_changes_done_at = time_now + DEFAULT_VIRTUAL_CHANGES_DONE_DELAY_SECS * 1000;
 583       update_rate_limiter_timeout (monitor, limiter->send_virtual_changes_done_at);
 584     }
 585 }
 586
 587 #define __G_DIRECTORY_MONITOR_C__
 588 #include "gioaliasdef.c"