move dconf-gvdb-utils from service into common

3 files changed, 255 insertions, 2 deletions

diff --git a/common/dconf-gvdb-utils.c b/common/dconf-gvdb-utils.c
new file mode 100644
index 0000000..e70e2dc
--- /dev/null
+++ b/common/dconf-gvdb-utils.c
@@ -0,0 +1,219 @@
+/*
+ * Copyright © 2010 Codethink Limited
+ * Copyright © 2012 Canonical Limited
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the licence, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Ryan Lortie <desrt@desrt.ca>
+ */
+
+#include "config.h"
+
+#include "dconf-gvdb-utils.h"
+
+#include "./dconf-paths.h"
+#include "../gvdb/gvdb-builder.h"
+#include "../gvdb/gvdb-reader.h"
+
+#include <errno.h>
+#include <glib.h>
+#include <glib/gstdio.h>
+#include <string.h>
+
+DConfChangeset *
+dconf_gvdb_utils_read_and_back_up_file (const gchar  *filename,
+                                        gboolean     *file_missing,
+                                        GError      **error)
+{
+  DConfChangeset *database;
+  GError *my_error = NULL;
+  GvdbTable *table = NULL;
+  gchar *contents;
+  gsize size;
+
+  if (g_file_get_contents (filename, &contents, &size, &my_error))
+    {
+      GBytes *bytes;
+
+      bytes = g_bytes_new_take (contents, size);
+      table = gvdb_table_new_from_bytes (bytes, FALSE, &my_error);
+      g_bytes_unref (bytes);
+    }
+
+  /* It is perfectly fine if the file does not exist -- then it's
+   * just empty.
+   */
+  if (g_error_matches (my_error, G_FILE_ERROR, G_FILE_ERROR_NOENT))
+    g_clear_error (&my_error);
+
+  /* Otherwise, we should report errors to prevent ourselves from
+   * overwriting the database in other situations...
+   */
+  if (g_error_matches (my_error, G_FILE_ERROR, G_FILE_ERROR_INVAL))
+    {
+      /* Move the database to a backup file, warn and continue with a new
+       * database. The alternative is erroring out and exiting the daemon,
+       * which leaves the user’s session essentially unusable.
+       *
+       * The code to find an unused backup filename is racy, but this is an
+       * error handling path. Who cares. */
+      g_autofree gchar *backup_filename = NULL;
+      guint i;
+
+      for (i = 0;
+           i < G_MAXUINT &&
+           (backup_filename == NULL || g_file_test (backup_filename, G_FILE_TEST_EXISTS));
+           i++)
+        {
+          g_free (backup_filename);
+          backup_filename = g_strdup_printf ("%s~%u", filename, i);
+        }
+
+      if (g_rename (filename, backup_filename) != 0)
+        g_warning ("Error renaming corrupt database from ‘%s’ to ‘%s’: %s",
+                   filename, backup_filename, g_strerror (errno));
+      else
+        g_warning ("Database ‘%s’ was corrupt: moved it to ‘%s’ and created an empty replacement",
+                   filename, backup_filename);
+
+      g_clear_error (&my_error);
+    }
+  else if (my_error)
+    {
+      g_propagate_prefixed_error (error, my_error, "Cannot open dconf database: ");
+      return NULL;
+    }
+
+  /* Only allocate once we know we are in a non-error situation */
+  database = dconf_changeset_new_database (NULL);
+
+  /* Fill the table up with the initial state */
+  if (table != NULL)
+    {
+      gchar **names;
+      gsize n_names;
+      gsize i;
+
+      names = gvdb_table_get_names (table, &n_names);
+      for (i = 0; i < n_names; i++)
+        {
+          if (dconf_is_key (names[i], NULL))
+            {
+              GVariant *value;
+
+              value = gvdb_table_get_value (table, names[i]);
+
+              if (value != NULL)
+                {
+                  dconf_changeset_set (database, names[i], value);
+                  g_variant_unref (value);
+                }
+            }
+
+          g_free (names[i]);
+        }
+
+      gvdb_table_free (table);
+      g_free (names);
+    }
+
+  if (file_missing)
+    *file_missing = (table == NULL);
+
+  return database;
+}
+
+static GvdbItem *
+dconf_gvdb_utils_get_parent (GHashTable  *table,
+                             const gchar *key)
+{
+  GvdbItem *grandparent, *parent;
+  gchar *parent_name;
+  gint len;
+
+  if (g_str_equal (key, "/"))
+    return NULL;
+
+  len = strlen (key);
+  if (key[len - 1] == '/')
+    len--;
+
+  while (key[len - 1] != '/')
+    len--;
+
+  parent_name = g_strndup (key, len);
+  parent = g_hash_table_lookup (table, parent_name);
+
+  if (parent == NULL)
+    {
+      parent = gvdb_hash_table_insert (table, parent_name);
+
+      grandparent = dconf_gvdb_utils_get_parent (table, parent_name);
+
+      if (grandparent != NULL)
+        gvdb_item_set_parent (parent, grandparent);
+    }
+
+  g_free (parent_name);
+
+  return parent;
+}
+
+static gboolean
+dconf_gvdb_utils_add_key (const gchar *path,
+                          GVariant    *value,
+                          gpointer     user_data)
+{
+  GHashTable *gvdb = user_data;
+  GvdbItem *item;
+
+  g_assert (g_hash_table_lookup (gvdb, path) == NULL);
+  item = gvdb_hash_table_insert (gvdb, path);
+  gvdb_item_set_parent (item, dconf_gvdb_utils_get_parent (gvdb, path));
+  gvdb_item_set_value (item, value);
+
+  return TRUE;
+}
+
+gboolean
+dconf_gvdb_utils_write_file (const gchar     *filename,
+                             DConfChangeset  *database,
+                             GError         **error)
+{
+  GHashTable *gvdb;
+  gboolean success;
+
+  gvdb = gvdb_hash_table_new (NULL, NULL);
+  dconf_changeset_all (database, dconf_gvdb_utils_add_key, gvdb);
+  success = gvdb_table_write_contents (gvdb, filename, FALSE, error);
+
+  if (!success)
+    {
+      gchar *dirname;
+
+      /* Maybe it failed because the directory doesn't exist.  Try
+       * again, after mkdir().
+       */
+      dirname = g_path_get_dirname (filename);
+      g_mkdir_with_parents (dirname, 0700);
+      g_free (dirname);
+
+      g_clear_error (error);
+      success = gvdb_table_write_contents (gvdb, filename, FALSE, error);
+    }
+
+  g_hash_table_unref (gvdb);
+
+  return success;
+}
diff --git a/common/dconf-gvdb-utils.h b/common/dconf-gvdb-utils.h
new file mode 100644
index 0000000..8d73133
--- /dev/null
+++ b/common/dconf-gvdb-utils.h
@@ -0,0 +1,33 @@
+/*
+ * Copyright © 2010 Codethink Limited
+ * Copyright © 2012 Canonical Limited
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the licence, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Ryan Lortie <desrt@desrt.ca>
+ */
+
+#ifndef __dconf_gvdb_utils_h__
+#define __dconf_gvdb_utils_h__
+
+#include "./dconf-changeset.h"
+
+DConfChangeset *                dconf_gvdb_utils_read_and_back_up_file  (const gchar     *filename,
+                                                                         gboolean        *file_missing,
+                                                                         GError         **error);
+gboolean                        dconf_gvdb_utils_write_file             (const gchar     *filename,
+                                                                         DConfChangeset  *database,
+                                                                         GError         **error);
+
+#endif /* __dconf_gvdb_utils_h__ */
diff --git a/common/meson.build b/common/meson.build
index befa9bc..e736ea8 100644
--- a/common/meson.build
+++ b/common/meson.build
@@ -15,18 +15,19 @@ sources = files(
   'dconf-changeset.c',
   'dconf-error.c',
   'dconf-paths.c',
+  'dconf-gvdb-utils.c',
 )
 
 libdconf_common = static_library(
   'dconf-common',
   sources: sources,
   include_directories: top_inc,
-  dependencies: glib_dep,
+  dependencies: [glib_dep, libgvdb_dep],
   c_args: dconf_c_args,
   pic: true,
 )
 
 libdconf_common_dep = declare_dependency(
-  dependencies: glib_dep,
+  dependencies: [glib_dep, libgvdb_dep],
   link_with: libdconf_common,
 )