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