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