gio/gkeyfilesettingsbackend.c

   1 /*
   2  * Copyright © 2010 Codethink Limited
   3  * Copyright © 2010 Novell, 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 licence, 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 Public
  16  * 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  * Authors: Vincent Untz <vuntz@gnome.org>
  21  *          Ryan Lortie <desrt@desrt.ca>
  22  */
  23
  24 #include "config.h"
  25
  26 #include "gkeyfilesettingsbackend.h"
  27
  28 #include <stdio.h>
  29 #include <string.h>
  30 #include <errno.h>
  31
  32 #include "gioerror.h"
  33 #include "giomodule.h"
  34 #include "gfile.h"
  35 #include "gfileinfo.h"
  36 #include "gfilemonitor.h"
  37
  38 #include "gioalias.h"
  39
  40 G_DEFINE_TYPE (GKeyfileSettingsBackend,
  41                g_keyfile_settings_backend,
  42                G_TYPE_SETTINGS_BACKEND)
  43
  44 struct _GKeyfileSettingsBackendPrivate
  45 {
  46   GHashTable   *table;
  47   GKeyFile     *keyfile;
  48   gboolean      writable;
  49   gchar        *file_path;
  50   gchar        *checksum;
  51   GFileMonitor *monitor;
  52 };
  53
  54 static GVariant *
  55 g_keyfile_settings_backend_read (GSettingsBackend   *backend,
  56                                  const gchar        *key,
  57                                  const GVariantType *expected_type,
  58                                  gboolean            default_value)
  59 {
  60   GKeyfileSettingsBackend *kf_backend = G_KEYFILE_SETTINGS_BACKEND (backend);
  61   GVariant *value;
  62
  63   if (default_value)
  64     return NULL;
  65
  66   value = g_hash_table_lookup (kf_backend->priv->table, key);
  67
  68   if (value != NULL)
  69     g_variant_ref (value);
  70
  71   return value;
  72 }
  73
  74 static gboolean
  75 g_keyfile_settings_backend_write_one (const gchar             *key,
  76                                       GVariant                *value,
  77                                       GKeyfileSettingsBackend *kf_backend)
  78 {
  79   const gchar *slash;
  80   const gchar *base_key;
  81   gchar       *path;
  82
  83   g_hash_table_replace (kf_backend->priv->table,
  84                         g_strdup (key), g_variant_ref (value));
  85
  86   slash = strrchr (key, '/');
  87   g_assert (slash != NULL);
  88   base_key = (slash + 1);
  89   path = g_strndup (key, slash - key + 1);
  90
  91   g_key_file_set_string (kf_backend->priv->keyfile,
  92                          path, base_key, g_variant_print (value, TRUE));
  93
  94   g_free (path);
  95
  96   return FALSE;
  97 }
  98
  99 static void
 100 g_keyfile_settings_backend_keyfile_write (GKeyfileSettingsBackend *kf_backend)
 101 {
 102   gchar *dirname;
 103   gchar *contents;
 104   gsize  length;
 105   GFile *file;
 106
 107   dirname = g_path_get_dirname (kf_backend->priv->file_path);
 108   if (!g_file_test (dirname, G_FILE_TEST_IS_DIR))
 109     g_mkdir_with_parents (dirname, 0700);
 110   g_free (dirname);
 111
 112   contents = g_key_file_to_data (kf_backend->priv->keyfile, &length, NULL);
 113
 114   file = g_file_new_for_path (kf_backend->priv->file_path);
 115   g_file_replace_contents (file, contents, length,
 116                            NULL, FALSE, G_FILE_CREATE_REPLACE_DESTINATION,
 117                            NULL, NULL, NULL);
 118   g_object_unref (file);
 119
 120   g_free (kf_backend->priv->checksum);
 121   kf_backend->priv->checksum = g_compute_checksum_for_string (G_CHECKSUM_SHA256, contents, length);
 122
 123   g_free (contents);
 124 }
 125
 126 static gboolean
 127 g_keyfile_settings_backend_write (GSettingsBackend *backend,
 128                                   const gchar      *key,
 129                                   GVariant         *value,
 130                                   gpointer          origin_tag)
 131 {
 132   GKeyfileSettingsBackend *kf_backend = G_KEYFILE_SETTINGS_BACKEND (backend);
 133
 134   g_keyfile_settings_backend_write_one (key, value, kf_backend);
 135   g_keyfile_settings_backend_keyfile_write (kf_backend);
 136
 137   g_settings_backend_changed (backend, key, origin_tag);
 138
 139   return TRUE;
 140 }
 141
 142 static gboolean
 143 g_keyfile_settings_backend_write_keys (GSettingsBackend *backend,
 144                                        GTree            *tree,
 145                                        gpointer          origin_tag)
 146 {
 147   GKeyfileSettingsBackend *kf_backend = G_KEYFILE_SETTINGS_BACKEND (backend);
 148
 149   g_tree_foreach (tree, (GTraverseFunc) g_keyfile_settings_backend_write_one, backend);
 150   g_keyfile_settings_backend_keyfile_write (kf_backend);
 151
 152   g_settings_backend_changed_tree (backend, tree, origin_tag);
 153
 154   return TRUE;
 155 }
 156
 157 static void
 158 g_keyfile_settings_backend_reset_path (GSettingsBackend *backend,
 159                                        const gchar      *path,
 160                                        gpointer         origin_tag)
 161 {
 162   GKeyfileSettingsBackend *kf_backend = G_KEYFILE_SETTINGS_BACKEND (backend);
 163   GPtrArray  *reset_array;
 164   GList      *hash_keys;
 165   GList      *l;
 166   gboolean    changed;
 167   gchar     **groups = NULL;
 168   gsize       groups_nb = 0;
 169   int         i;
 170
 171   reset_array = g_ptr_array_new_with_free_func (g_free);
 172
 173   hash_keys = g_hash_table_get_keys (kf_backend->priv->table);
 174   for (l = hash_keys; l != NULL; l = l->next)
 175     {
 176       if (g_str_has_prefix (l->data, path))
 177         {
 178           g_hash_table_remove (kf_backend->priv->table, l->data);
 179           g_ptr_array_add (reset_array, g_strdup (l->data));
 180         }
 181     }
 182   g_list_free (hash_keys);
 183
 184   changed = FALSE;
 185   groups = g_key_file_get_groups (kf_backend->priv->keyfile, &groups_nb);
 186   for (i = 0; i < groups_nb; i++)
 187     {
 188       if (g_str_has_prefix (groups[i], path))
 189         changed = g_key_file_remove_group (kf_backend->priv->keyfile, groups[i], NULL) || changed;
 190     }
 191   g_strfreev (groups);
 192
 193   if (changed)
 194     g_keyfile_settings_backend_keyfile_write (kf_backend);
 195
 196   if (reset_array->len > 0)
 197     {
 198       /* the array has to be NULL-terminated */
 199       g_ptr_array_add (reset_array, NULL);
 200       g_settings_backend_keys_changed (G_SETTINGS_BACKEND (kf_backend),
 201                                        "",
 202                                        (const gchar **) reset_array->pdata,
 203                                        origin_tag);
 204     }
 205
 206   g_ptr_array_free (reset_array, TRUE);
 207 }
 208
 209 static void
 210 g_keyfile_settings_backend_reset (GSettingsBackend *backend,
 211                                   const gchar      *key,
 212                                   gpointer          origin_tag)
 213 {
 214   GKeyfileSettingsBackend *kf_backend = G_KEYFILE_SETTINGS_BACKEND (backend);
 215   gboolean     had_key;
 216   const gchar *slash;
 217   const gchar *base_key;
 218   gchar       *path;
 219
 220   had_key = g_hash_table_lookup_extended (kf_backend->priv->table, key, NULL, NULL);
 221   if (had_key)
 222     g_hash_table_remove (kf_backend->priv->table, key);
 223
 224   slash = strrchr (key, '/');
 225   g_assert (slash != NULL);
 226   base_key = (slash + 1);
 227   path = g_strndup (key, slash - key + 1);
 228
 229   if (g_key_file_remove_key (kf_backend->priv->keyfile, path, base_key, NULL))
 230     g_keyfile_settings_backend_keyfile_write (kf_backend);
 231
 232   g_free (path);
 233
 234   if (had_key)
 235     g_settings_backend_changed (G_SETTINGS_BACKEND (kf_backend), key, origin_tag);
 236 }
 237
 238 static gboolean
 239 g_keyfile_settings_backend_get_writable (GSettingsBackend *backend,
 240                                          const gchar      *name)
 241 {
 242   GKeyfileSettingsBackend *kf_backend = G_KEYFILE_SETTINGS_BACKEND (backend);
 243
 244   return kf_backend->priv->writable;
 245 }
 246
 247 static void
 248 g_keyfile_settings_backend_keyfile_reload (GKeyfileSettingsBackend *kf_backend)
 249 {
 250   gchar       *contents = NULL;
 251   gsize        length = 0;
 252   gchar       *new_checksum;
 253   GHashTable  *loaded_keys;
 254   GPtrArray   *changed_array;
 255   gchar      **groups = NULL;
 256   gsize        groups_nb = 0;
 257   int          i;
 258   GList       *keys_l = NULL;
 259   GList       *l;
 260
 261   if (!g_file_get_contents (kf_backend->priv->file_path,
 262                             &contents, &length, NULL))
 263     {
 264       contents = g_strdup ("");
 265       length = 0;
 266     }
 267
 268   new_checksum = g_compute_checksum_for_string (G_CHECKSUM_SHA256, contents, length);
 269
 270   if (g_strcmp0 (kf_backend->priv->checksum, new_checksum) == 0)
 271     {
 272       g_free (new_checksum);
 273       return;
 274     }
 275
 276   if (kf_backend->priv->checksum != NULL)
 277     g_free (kf_backend->priv->checksum);
 278   kf_backend->priv->checksum = new_checksum;
 279
 280   if (kf_backend->priv->keyfile != NULL)
 281     g_key_file_free (kf_backend->priv->keyfile);
 282
 283   kf_backend->priv->keyfile = g_key_file_new ();
 284
 285   /* we just silently ignore errors: there's not much we can do about them */
 286   if (length > 0)
 287     g_key_file_load_from_data (kf_backend->priv->keyfile, contents, length,
 288                                G_KEY_FILE_KEEP_COMMENTS|G_KEY_FILE_KEEP_TRANSLATIONS, NULL);
 289
 290   loaded_keys = g_hash_table_new_full (g_str_hash, g_str_equal, g_free, NULL);
 291   changed_array = g_ptr_array_new_with_free_func (g_free);
 292
 293   /* Load keys from the keyfile */
 294   groups = g_key_file_get_groups (kf_backend->priv->keyfile, &groups_nb);
 295   for (i = 0; i < groups_nb; i++)
 296     {
 297       gchar **keys = NULL;
 298       gsize   keys_nb = 0;
 299       int     j;
 300
 301       keys = g_key_file_get_keys (kf_backend->priv->keyfile, groups[i], &keys_nb, NULL);
 302       if (keys == NULL)
 303         continue;
 304
 305       for (j = 0; j < keys_nb; j++)
 306         {
 307           gchar    *value;
 308           gchar    *full_key;
 309           GVariant *old_variant;
 310           GVariant *variant;
 311
 312           value = g_key_file_get_string (kf_backend->priv->keyfile, groups[i], keys[j], NULL);
 313           if (value == NULL)
 314             continue;
 315
 316           variant = g_variant_new_parsed (value);
 317           g_free (value);
 318
 319           if (variant == NULL)
 320             continue;
 321
 322           full_key = g_strjoin ("", groups[i], keys[j], NULL),
 323           g_hash_table_insert (loaded_keys, full_key, GINT_TO_POINTER(TRUE));
 324
 325           old_variant = g_hash_table_lookup (kf_backend->priv->table, full_key);
 326
 327           if (old_variant == NULL || !g_variant_equal (old_variant, variant))
 328             {
 329               g_ptr_array_add (changed_array, g_strdup (full_key));
 330               g_hash_table_replace (kf_backend->priv->table,
 331                                     g_strdup (full_key),
 332                                     g_variant_ref_sink (variant));
 333             }
 334           else
 335             g_variant_unref (variant);
 336         }
 337
 338       g_strfreev (keys);
 339     }
 340   g_strfreev (groups);
 341
 342   /* Remove keys that were in the hashtable but not in the keyfile */
 343   keys_l = g_hash_table_get_keys (kf_backend->priv->table);
 344   for (l = keys_l; l != NULL; l = l->next)
 345     {
 346       gchar *key = l->data;
 347
 348       if (g_hash_table_lookup_extended (loaded_keys, key, NULL, NULL))
 349         continue;
 350
 351       g_ptr_array_add (changed_array, g_strdup (key));
 352       g_hash_table_remove (kf_backend->priv->table, key);
 353     }
 354   g_list_free (keys_l);
 355
 356   if (changed_array->len > 0)
 357     {
 358       /* the array has to be NULL-terminated */
 359       g_ptr_array_add (changed_array, NULL);
 360       g_settings_backend_keys_changed (G_SETTINGS_BACKEND (kf_backend),
 361                                        "",
 362                                        (const gchar **) changed_array->pdata,
 363                                        NULL);
 364     }
 365
 366   g_hash_table_unref (loaded_keys);
 367   g_ptr_array_free (changed_array, TRUE);
 368 }
 369
 370 static gboolean
 371 g_keyfile_settings_backend_keyfile_writable (GFile *file)
 372 {
 373   GFileInfo *fileinfo;
 374   GError    *error;
 375   gboolean   writable = FALSE;
 376
 377   error = NULL;
 378   fileinfo = g_file_query_info (file, "access::*",
 379                                 G_FILE_QUERY_INFO_NONE, NULL, &error);
 380
 381   if (fileinfo == NULL)
 382     {
 383       if (g_error_matches (error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND))
 384         {
 385           GFile *parent;
 386
 387           parent = g_file_get_parent (file);
 388           if (parent)
 389             {
 390               writable = g_keyfile_settings_backend_keyfile_writable (parent);
 391               g_object_unref (parent);
 392             }
 393         }
 394
 395       g_error_free (error);
 396
 397       return writable;
 398     }
 399
 400   /* We don't want to mark the backend as writable if the file is not readable,
 401    * since it means we won't be able to load the content of the file, and we'll
 402    * lose data. */
 403   writable =
 404         g_file_info_get_attribute_boolean (fileinfo, G_FILE_ATTRIBUTE_ACCESS_CAN_READ) &&
 405         g_file_info_get_attribute_boolean (fileinfo, G_FILE_ATTRIBUTE_ACCESS_CAN_WRITE);
 406   g_object_unref (fileinfo);
 407
 408   return writable;
 409 }
 410
 411 static void
 412 g_keyfile_settings_backend_keyfile_changed (GFileMonitor      *monitor,
 413                                             GFile             *file,
 414                                             GFile             *other_file,
 415                                             GFileMonitorEvent  event_type,
 416                                             gpointer           user_data)
 417 {
 418   GKeyfileSettingsBackend *kf_backend;
 419
 420   if (event_type != G_FILE_MONITOR_EVENT_CHANGED &&
 421       event_type != G_FILE_MONITOR_EVENT_CREATED &&
 422       event_type != G_FILE_MONITOR_EVENT_DELETED &&
 423       event_type != G_FILE_MONITOR_EVENT_ATTRIBUTE_CHANGED)
 424     return;
 425
 426   kf_backend = G_KEYFILE_SETTINGS_BACKEND (user_data);
 427
 428   if (event_type == G_FILE_MONITOR_EVENT_ATTRIBUTE_CHANGED)
 429     {
 430       gboolean writable;
 431
 432       writable = g_keyfile_settings_backend_keyfile_writable (file);
 433
 434       if (kf_backend->priv->writable == writable)
 435         return;
 436
 437       kf_backend->priv->writable = writable;
 438       if (!writable)
 439         return;
 440       /* else: reload the file since it was possibly not readable before */
 441     }
 442
 443   g_keyfile_settings_backend_keyfile_reload (kf_backend);
 444 }
 445
 446 static void
 447 g_keyfile_settings_backend_finalize (GObject *object)
 448 {
 449   GKeyfileSettingsBackend *kf_backend = G_KEYFILE_SETTINGS_BACKEND (object);
 450
 451   g_hash_table_unref (kf_backend->priv->table);
 452   kf_backend->priv->table = NULL;
 453
 454   g_key_file_free (kf_backend->priv->keyfile);
 455   kf_backend->priv->keyfile = NULL;
 456
 457   g_free (kf_backend->priv->file_path);
 458   kf_backend->priv->file_path = NULL;
 459
 460   g_free (kf_backend->priv->checksum);
 461   kf_backend->priv->checksum = NULL;
 462
 463   g_file_monitor_cancel (kf_backend->priv->monitor);
 464   g_object_unref (kf_backend->priv->monitor);
 465   kf_backend->priv->monitor = NULL;
 466
 467   G_OBJECT_CLASS (g_keyfile_settings_backend_parent_class)
 468     ->finalize (object);
 469 }
 470
 471 static void
 472 g_keyfile_settings_backend_init (GKeyfileSettingsBackend *kf_backend)
 473 {
 474   kf_backend->priv = G_TYPE_INSTANCE_GET_PRIVATE (kf_backend,
 475                                                   G_TYPE_KEYFILE_SETTINGS_BACKEND,
 476                                                   GKeyfileSettingsBackendPrivate);
 477   kf_backend->priv->table =
 478     g_hash_table_new_full (g_str_hash, g_str_equal, g_free,
 479                            (GDestroyNotify) g_variant_unref);
 480
 481   kf_backend->priv->keyfile = NULL;
 482   kf_backend->priv->writable = FALSE;
 483   kf_backend->priv->file_path = NULL;
 484   kf_backend->priv->checksum = NULL;
 485   kf_backend->priv->monitor = NULL;
 486 }
 487
 488 static void
 489 g_keyfile_settings_backend_class_init (GKeyfileSettingsBackendClass *class)
 490 {
 491   GSettingsBackendClass *backend_class = G_SETTINGS_BACKEND_CLASS (class);
 492   GObjectClass *object_class = G_OBJECT_CLASS (class);
 493
 494   object_class->finalize = g_keyfile_settings_backend_finalize;
 495
 496   backend_class->read = g_keyfile_settings_backend_read;
 497   backend_class->write = g_keyfile_settings_backend_write;
 498   backend_class->write_keys = g_keyfile_settings_backend_write_keys;
 499   backend_class->reset = g_keyfile_settings_backend_reset;
 500   backend_class->reset_path = g_keyfile_settings_backend_reset_path;
 501   backend_class->get_writable = g_keyfile_settings_backend_get_writable;
 502   /* No need to implement subscribed/unsubscribe: the only point would be to
 503    * stop monitoring the file when there's no GSettings anymore, which is no
 504    * big win. */
 505
 506   g_type_class_add_private (class, sizeof (GKeyfileSettingsBackendPrivate));
 507 }
 508
 509 static GKeyfileSettingsBackend *
 510 g_keyfile_settings_backend_new (const gchar *filename)
 511 {
 512   GKeyfileSettingsBackend *kf_backend;
 513   GFile *file;
 514
 515   kf_backend = g_object_new (G_TYPE_KEYFILE_SETTINGS_BACKEND, NULL);
 516   kf_backend->priv->file_path = g_strdup (filename);
 517
 518   file = g_file_new_for_path (kf_backend->priv->file_path);
 519
 520   kf_backend->priv->writable = g_keyfile_settings_backend_keyfile_writable (file);
 521
 522   kf_backend->priv->monitor = g_file_monitor_file (file, G_FILE_MONITOR_SEND_MOVED, NULL, NULL);
 523   g_signal_connect (kf_backend->priv->monitor, "changed",
 524                     (GCallback)g_keyfile_settings_backend_keyfile_changed, kf_backend);
 525
 526   g_object_unref (file);
 527
 528   g_keyfile_settings_backend_keyfile_reload (kf_backend);
 529
 530   return kf_backend;
 531 }
 532
 533 /**
 534  * g_settings_backend_setup_keyfile:
 535  * @context: a context string (not %NULL or "")
 536  * @filename: a filename
 537  *
 538  * Sets up a keyfile for use with #GSettings.
 539  *
 540  * If you create a #GSettings with its context property set to @context
 541  * then the settings will be stored in the keyfile at @filename.  See
 542  * g_settings_new_with_context().
 543  *
 544  * The keyfile must be setup before any settings objects are created
 545  * for the named context.
 546  *
 547  * It is not possible to specify a keyfile for the default context.
 548  *
 549  * If the path leading up to @filename does not exist, it will be
 550  * recursively created with user-only permissions.  If the keyfile is
 551  * not writable, any #GSettings objects created using @context will
 552  * return %FALSE for any calls to g_settings_is_writable() and any
 553  * attempts to write will fail.
 554  *
 555  * Since: 2.26
 556  */
 557 void
 558 g_settings_backend_setup_keyfile (const gchar *context,
 559                                   const gchar *filename)
 560 {
 561   GKeyfileSettingsBackend *kf_backend;
 562
 563   kf_backend = g_keyfile_settings_backend_new (filename);
 564   g_settings_backend_setup (context, G_SETTINGS_BACKEND (kf_backend));
 565   g_object_unref (kf_backend);
 566 }
 567
 568 #define __G_KEYFILE_SETTINGS_BACKEND_C__
 569 #include "gioaliasdef.c"