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