gio/gdelayedsettingsbackend.c

   1 /*
   2  * Copyright © 2009, 2010 Codethink Limited
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the licence, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  *
  19  * Author: Ryan Lortie <desrt@desrt.ca>
  20  */
  21
  22 #include "config.h"
  23
  24 #include "gdelayedsettingsbackend.h"
  25 #include "gsettingsbackendinternal.h"
  26
  27 #include <string.h>
  28
  29
  30 struct _GDelayedSettingsBackendPrivate
  31 {
  32   GSettingsBackend *backend;
  33   GStaticMutex lock;
  34   GTree *delayed;
  35
  36   GMainContext *owner_context;
  37   gpointer owner;
  38 };
  39
  40 G_DEFINE_TYPE (GDelayedSettingsBackend,
  41                g_delayed_settings_backend,
  42                G_TYPE_SETTINGS_BACKEND)
  43
  44 static gboolean
  45 invoke_notify_unapplied (gpointer data)
  46 {
  47   g_object_notify (data, "has-unapplied");
  48   g_object_unref (data);
  49
  50   return FALSE;
  51 }
  52
  53 static void
  54 g_delayed_settings_backend_notify_unapplied (GDelayedSettingsBackend *delayed)
  55 {
  56   GMainContext *target_context;
  57   GObject *target;
  58
  59   g_static_mutex_lock (&delayed->priv->lock);
  60   if (delayed->priv->owner)
  61     {
  62       target_context = delayed->priv->owner_context;
  63       target = g_object_ref (delayed->priv->owner);
  64     }
  65   else
  66     {
  67       target_context = NULL;
  68       target = NULL;
  69     }
  70   g_static_mutex_unlock (&delayed->priv->lock);
  71
  72   if (target != NULL)
  73     {
  74       if (g_settings_backend_get_active_context () != target_context)
  75         {
  76           GSource *source;
  77
  78           source = g_idle_source_new ();
  79           g_source_set_priority (source, G_PRIORITY_DEFAULT);
  80           g_source_set_callback (source, invoke_notify_unapplied,
  81                                  target, g_object_unref);
  82           g_source_attach (source, target_context);
  83           g_source_unref (source);
  84         }
  85       else
  86         invoke_notify_unapplied (target);
  87     }
  88 }
  89
  90
  91 static GVariant *
  92 g_delayed_settings_backend_read (GSettingsBackend   *backend,
  93                                  const gchar        *key,
  94                                  const GVariantType *expected_type,
  95                                  gboolean            default_value)
  96 {
  97   GDelayedSettingsBackend *delayed = G_DELAYED_SETTINGS_BACKEND (backend);
  98   gpointer result = NULL;
  99
 100   if (!default_value)
 101     {
 102       g_static_mutex_lock (&delayed->priv->lock);
 103       if (g_tree_lookup_extended (delayed->priv->delayed, key, NULL, &result))
 104         {
 105           /* NULL in the tree means we should consult the default value */
 106           if (result != NULL)
 107             g_variant_ref (result);
 108           else
 109             default_value = TRUE;
 110         }
 111       g_static_mutex_unlock (&delayed->priv->lock);
 112     }
 113
 114   if (result == NULL)
 115     result = g_settings_backend_read (delayed->priv->backend, key,
 116                                       expected_type, default_value);
 117
 118   return result;
 119 }
 120
 121 static gboolean
 122 g_delayed_settings_backend_write (GSettingsBackend *backend,
 123                                   const gchar      *key,
 124                                   GVariant         *value,
 125                                   gpointer          origin_tag)
 126 {
 127   GDelayedSettingsBackend *delayed = G_DELAYED_SETTINGS_BACKEND (backend);
 128   gboolean was_empty;
 129
 130   g_static_mutex_lock (&delayed->priv->lock);
 131   was_empty = g_tree_nnodes (delayed->priv->delayed) == 0;
 132   g_tree_insert (delayed->priv->delayed, g_strdup (key),
 133                  g_variant_ref_sink (value));
 134   g_static_mutex_unlock (&delayed->priv->lock);
 135
 136   g_settings_backend_changed (backend, key, origin_tag);
 137
 138   if (was_empty)
 139     g_delayed_settings_backend_notify_unapplied (delayed);
 140
 141   return TRUE;
 142 }
 143
 144 static gboolean
 145 add_to_tree (gpointer key,
 146              gpointer value,
 147              gpointer user_data)
 148 {
 149   g_tree_insert (user_data, g_strdup (key), g_variant_ref (value));
 150   return FALSE;
 151 }
 152
 153 static gboolean
 154 g_delayed_settings_backend_write_tree (GSettingsBackend *backend,
 155                                        GTree            *tree,
 156                                        gpointer          origin_tag)
 157 {
 158   GDelayedSettingsBackend *delayed = G_DELAYED_SETTINGS_BACKEND (backend);
 159   gboolean was_empty;
 160
 161   g_static_mutex_lock (&delayed->priv->lock);
 162   was_empty = g_tree_nnodes (delayed->priv->delayed) == 0;
 163
 164   g_tree_foreach (tree, add_to_tree, delayed->priv->delayed);
 165   g_static_mutex_unlock (&delayed->priv->lock);
 166
 167   g_settings_backend_changed_tree (backend, tree, origin_tag);
 168
 169   if (was_empty)
 170     g_delayed_settings_backend_notify_unapplied (delayed);
 171
 172   return TRUE;
 173 }
 174
 175 static gboolean
 176 g_delayed_settings_backend_get_writable (GSettingsBackend *backend,
 177                                          const gchar      *name)
 178 {
 179   GDelayedSettingsBackend *delayed = G_DELAYED_SETTINGS_BACKEND (backend);
 180
 181   return g_settings_backend_get_writable (delayed->priv->backend, name);
 182 }
 183
 184 static void
 185 g_delayed_settings_backend_reset (GSettingsBackend *backend,
 186                                   const gchar      *key,
 187                                   gpointer          origin_tag)
 188 {
 189   GDelayedSettingsBackend *delayed = G_DELAYED_SETTINGS_BACKEND (backend);
 190   gboolean was_empty;
 191
 192   g_static_mutex_lock (&delayed->priv->lock);
 193   was_empty = g_tree_nnodes (delayed->priv->delayed) == 0;
 194   g_tree_insert (delayed->priv->delayed, g_strdup (key), NULL);
 195   g_static_mutex_unlock (&delayed->priv->lock);
 196
 197   if (was_empty)
 198     g_delayed_settings_backend_notify_unapplied (delayed);
 199 }
 200
 201 static void
 202 g_delayed_settings_backend_subscribe (GSettingsBackend *backend,
 203                                       const char       *name)
 204 {
 205   GDelayedSettingsBackend *delayed = G_DELAYED_SETTINGS_BACKEND (backend);
 206
 207   g_settings_backend_subscribe (delayed->priv->backend, name);
 208 }
 209
 210 static void
 211 g_delayed_settings_backend_unsubscribe (GSettingsBackend *backend,
 212                                         const char       *name)
 213 {
 214   GDelayedSettingsBackend *delayed = G_DELAYED_SETTINGS_BACKEND (backend);
 215
 216   g_settings_backend_unsubscribe (delayed->priv->backend, name);
 217 }
 218
 219 static GPermission *
 220 g_delayed_settings_backend_get_permission (GSettingsBackend *backend,
 221                                            const gchar      *path)
 222 {
 223   GDelayedSettingsBackend *delayed = G_DELAYED_SETTINGS_BACKEND (backend);
 224
 225   return g_settings_backend_get_permission (delayed->priv->backend, path);
 226 }
 227
 228
 229 /* method calls */
 230 gboolean
 231 g_delayed_settings_backend_get_has_unapplied (GDelayedSettingsBackend *delayed)
 232 {
 233   /* we don't need to lock for this... */
 234
 235   return g_tree_nnodes (delayed->priv->delayed) > 0;
 236 }
 237
 238 void
 239 g_delayed_settings_backend_apply (GDelayedSettingsBackend *delayed)
 240 {
 241   if (g_tree_nnodes (delayed->priv->delayed) > 0)
 242     {
 243       gboolean success;
 244       GTree *tmp;
 245
 246       g_static_mutex_lock (&delayed->priv->lock);
 247       tmp = delayed->priv->delayed;
 248       delayed->priv->delayed = g_settings_backend_create_tree ();
 249       success = g_settings_backend_write_tree (delayed->priv->backend,
 250                                                tmp, delayed->priv);
 251       g_static_mutex_unlock (&delayed->priv->lock);
 252
 253       if (!success)
 254         g_settings_backend_changed_tree (G_SETTINGS_BACKEND (delayed),
 255                                          tmp, NULL);
 256
 257       g_tree_unref (tmp);
 258
 259       g_delayed_settings_backend_notify_unapplied (delayed);
 260     }
 261 }
 262
 263 void
 264 g_delayed_settings_backend_revert (GDelayedSettingsBackend *delayed)
 265 {
 266   if (g_tree_nnodes (delayed->priv->delayed) > 0)
 267     {
 268       GTree *tmp;
 269
 270       g_static_mutex_lock (&delayed->priv->lock);
 271       tmp = delayed->priv->delayed;
 272       delayed->priv->delayed = g_settings_backend_create_tree ();
 273       g_static_mutex_unlock (&delayed->priv->lock);
 274       g_settings_backend_changed_tree (G_SETTINGS_BACKEND (delayed), tmp, NULL);
 275       g_tree_unref (tmp);
 276
 277       g_delayed_settings_backend_notify_unapplied (delayed);
 278     }
 279 }
 280
 281 /* change notification */
 282 static void
 283 delayed_backend_changed (GObject          *target,
 284                          GSettingsBackend *backend,
 285                          const gchar      *key,
 286                          gpointer          origin_tag)
 287 {
 288   GDelayedSettingsBackend *delayed = G_DELAYED_SETTINGS_BACKEND (target);
 289
 290   if (origin_tag != delayed->priv)
 291     g_settings_backend_changed (G_SETTINGS_BACKEND (delayed),
 292                                 key, origin_tag);
 293 }
 294
 295 static void
 296 delayed_backend_keys_changed (GObject             *target,
 297                               GSettingsBackend    *backend,
 298                               const gchar         *path,
 299                               const gchar * const *items,
 300                               gpointer             origin_tag)
 301 {
 302   GDelayedSettingsBackend *delayed = G_DELAYED_SETTINGS_BACKEND (target);
 303
 304   if (origin_tag != delayed->priv)
 305     g_settings_backend_keys_changed (G_SETTINGS_BACKEND (delayed),
 306                                      path, items, origin_tag);
 307 }
 308
 309 static void
 310 delayed_backend_path_changed (GObject          *target,
 311                               GSettingsBackend *backend,
 312                               const gchar      *path,
 313                               gpointer          origin_tag)
 314 {
 315   GDelayedSettingsBackend *delayed = G_DELAYED_SETTINGS_BACKEND (target);
 316
 317   if (origin_tag != delayed->priv)
 318     g_settings_backend_path_changed (G_SETTINGS_BACKEND (delayed),
 319                                      path, origin_tag);
 320 }
 321
 322 static void
 323 delayed_backend_writable_changed (GObject          *target,
 324                                   GSettingsBackend *backend,
 325                                   const gchar      *key)
 326 {
 327   GDelayedSettingsBackend *delayed = G_DELAYED_SETTINGS_BACKEND (target);
 328   gboolean last_one = FALSE;
 329
 330   g_static_mutex_lock (&delayed->priv->lock);
 331
 332   if (g_tree_lookup (delayed->priv->delayed, key) &&
 333       !g_settings_backend_get_writable (delayed->priv->backend, key))
 334     {
 335       /* drop the key from our changeset if it just became read-only.
 336        * no need to signal since the writable change below implies it.
 337        */
 338       g_tree_remove (delayed->priv->delayed, key);
 339
 340       /* if that was the only key... */
 341       last_one = g_tree_nnodes (delayed->priv->delayed) == 0;
 342     }
 343
 344   g_static_mutex_unlock (&delayed->priv->lock);
 345
 346   if (last_one)
 347     g_delayed_settings_backend_notify_unapplied (delayed);
 348
 349   g_settings_backend_writable_changed (G_SETTINGS_BACKEND (delayed), key);
 350 }
 351
 352 /* slow method until we get foreach-with-remove in GTree
 353  */
 354 typedef struct
 355 {
 356   const gchar *path;
 357   const gchar **keys;
 358   gsize index;
 359 } CheckPrefixState;
 360
 361 static gboolean
 362 check_prefix (gpointer key,
 363               gpointer value,
 364               gpointer data)
 365 {
 366   CheckPrefixState *state = data;
 367
 368   if (g_str_has_prefix (key, state->path))
 369     state->keys[state->index++] = key;
 370
 371   return FALSE;
 372 }
 373
 374 static void
 375 delayed_backend_path_writable_changed (GObject          *target,
 376                                        GSettingsBackend *backend,
 377                                        const gchar      *path)
 378 {
 379   GDelayedSettingsBackend *delayed = G_DELAYED_SETTINGS_BACKEND (target);
 380   gboolean last_one = FALSE;
 381   gsize n_keys;
 382
 383   g_static_mutex_lock (&delayed->priv->lock);
 384
 385   n_keys = g_tree_nnodes (delayed->priv->delayed);
 386
 387   if (n_keys > 0)
 388     {
 389       CheckPrefixState state = { path, g_new (const gchar *, n_keys) };
 390       gsize i;
 391
 392       /* collect a list of possibly-affected keys (ie: matching the path) */
 393       g_tree_foreach (delayed->priv->delayed, check_prefix, &state);
 394
 395       /* drop the keys that have been affected */
 396       for (i = 0; i < state.index; i++)
 397         if (!g_settings_backend_get_writable (delayed->priv->backend,
 398                                               state.keys[i]))
 399           g_tree_remove (delayed->priv->delayed, state.keys[i]);
 400
 401       g_free (state.keys);
 402
 403       last_one = g_tree_nnodes (delayed->priv->delayed) == 0;
 404     }
 405
 406   g_static_mutex_unlock (&delayed->priv->lock);
 407
 408   if (last_one)
 409     g_delayed_settings_backend_notify_unapplied (delayed);
 410
 411   g_settings_backend_path_writable_changed (G_SETTINGS_BACKEND (delayed),
 412                                             path);
 413 }
 414
 415 static void
 416 g_delayed_settings_backend_finalize (GObject *object)
 417 {
 418   GDelayedSettingsBackend *delayed = G_DELAYED_SETTINGS_BACKEND (object);
 419
 420   g_static_mutex_free (&delayed->priv->lock);
 421   g_object_unref (delayed->priv->backend);
 422   g_tree_unref (delayed->priv->delayed);
 423
 424   /* if our owner is still alive, why are we finalizing? */
 425   g_assert (delayed->priv->owner == NULL);
 426
 427   G_OBJECT_CLASS (g_delayed_settings_backend_parent_class)
 428     ->finalize (object);
 429 }
 430
 431 static void
 432 g_delayed_settings_backend_class_init (GDelayedSettingsBackendClass *class)
 433 {
 434   GSettingsBackendClass *backend_class = G_SETTINGS_BACKEND_CLASS (class);
 435   GObjectClass *object_class = G_OBJECT_CLASS (class);
 436
 437   g_type_class_add_private (class, sizeof (GDelayedSettingsBackendPrivate));
 438
 439   backend_class->read = g_delayed_settings_backend_read;
 440   backend_class->write = g_delayed_settings_backend_write;
 441   backend_class->write_tree = g_delayed_settings_backend_write_tree;
 442   backend_class->reset = g_delayed_settings_backend_reset;
 443   backend_class->get_writable = g_delayed_settings_backend_get_writable;
 444   backend_class->subscribe = g_delayed_settings_backend_subscribe;
 445   backend_class->unsubscribe = g_delayed_settings_backend_unsubscribe;
 446   backend_class->get_permission = g_delayed_settings_backend_get_permission;
 447
 448   object_class->finalize = g_delayed_settings_backend_finalize;
 449 }
 450
 451 static void
 452 g_delayed_settings_backend_init (GDelayedSettingsBackend *delayed)
 453 {
 454   delayed->priv =
 455     G_TYPE_INSTANCE_GET_PRIVATE (delayed, G_TYPE_DELAYED_SETTINGS_BACKEND,
 456                                  GDelayedSettingsBackendPrivate);
 457
 458   delayed->priv->delayed = g_settings_backend_create_tree ();
 459   g_static_mutex_init (&delayed->priv->lock);
 460 }
 461
 462 static void
 463 g_delayed_settings_backend_disown (gpointer  data,
 464                                    GObject  *where_the_object_was)
 465 {
 466   GDelayedSettingsBackend *delayed = data;
 467
 468   g_static_mutex_lock (&delayed->priv->lock);
 469   delayed->priv->owner_context = NULL;
 470   delayed->priv->owner = NULL;
 471   g_static_mutex_unlock (&delayed->priv->lock);
 472 }
 473
 474 GDelayedSettingsBackend *
 475 g_delayed_settings_backend_new (GSettingsBackend *backend,
 476                                 gpointer          owner,
 477                                 GMainContext     *owner_context)
 478 {
 479   static GSettingsListenerVTable vtable = {
 480     delayed_backend_changed,
 481     delayed_backend_path_changed,
 482     delayed_backend_keys_changed,
 483     delayed_backend_writable_changed,
 484     delayed_backend_path_writable_changed
 485   };
 486   GDelayedSettingsBackend *delayed;
 487
 488   delayed = g_object_new (G_TYPE_DELAYED_SETTINGS_BACKEND, NULL);
 489   delayed->priv->backend = g_object_ref (backend);
 490   delayed->priv->owner_context = owner_context;
 491   delayed->priv->owner = owner;
 492
 493   g_object_weak_ref (owner, g_delayed_settings_backend_disown, delayed);
 494
 495   g_settings_backend_watch (delayed->priv->backend,
 496                             &vtable, G_OBJECT (delayed), NULL);
 497
 498   return delayed;
 499 }