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Diffstat (limited to 'src/librygel-db/database.vala')
| -rw-r--r-- | src/librygel-db/database.vala | 219 |
1 files changed, 219 insertions, 0 deletions
diff --git a/src/librygel-db/database.vala b/src/librygel-db/database.vala new file mode 100644 index 00000000..25b3f974 --- /dev/null +++ b/src/librygel-db/database.vala @@ -0,0 +1,219 @@ +/* + * Copyright (C) 2009,2011 Jens Georg <mail@jensge.org>. + * + * Author: Jens Georg <mail@jensge.org> + * + * This file is part of Rygel. + * + * Rygel 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 License, or + * (at your option) any later version. + * + * Rygel 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 program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + */ + +using Sqlite; + +public errordomain Rygel.Database.DatabaseError { + IO_ERROR, + SQLITE_ERROR +} + +namespace Rygel.Database { + extern static int utf8_collate_str (uint8[] a, uint8[] b); + + /** + * Special GValue to pass to exec or exec_cursor to bind a column to + * NULL + */ + public static GLib.Value @null () { + GLib.Value v = GLib.Value (typeof (void *)); + v.set_pointer (null); + + return v; + } +} + +/** + * This class is a thin wrapper around SQLite's database object. + * + * It adds statement preparation based on GValue and a cancellable exec + * function. + */ +public class Rygel.Database.Database : SqliteWrapper { + + /** + * Function to implement the custom SQL function 'contains' + */ + private static void utf8_contains (Sqlite.Context context, + Sqlite.Value[] args) + requires (args.length == 2) { + if (args[0].to_text () == null || + args[1].to_text () == null) { + context.result_int (0); + + return; + } + + var pattern = Regex.escape_string (args[1].to_text ()); + if (Regex.match_simple (pattern, + args[0].to_text (), + RegexCompileFlags.CASELESS)) { + context.result_int (1); + } else { + context.result_int (0); + } + } + + /** + * Function to implement the custom SQLite collation 'CASEFOLD'. + * + * Uses utf8 case-fold to compare the strings. + */ + private static int utf8_collate (int alen, void* a, int blen, void* b) { + // unowned to prevent array copy + unowned uint8[] _a = (uint8[]) a; + _a.length = alen; + + unowned uint8[] _b = (uint8[]) b; + _b.length = blen; + + return utf8_collate_str (_a, _b); + } + + /** + * Open a database in the user's cache directory as defined by XDG + * + * @param name of the database, used to build full path + * (<cache-dir>/rygel/<name>.db) + */ + public Database (string name) throws DatabaseError { + string db_file; + + if (name != ":memory:") { + var dirname = Path.build_filename ( + Environment.get_user_cache_dir (), + "rygel"); + DirUtils.create_with_parents (dirname, 0750); + db_file = Path.build_filename (dirname, "%s.db".printf (name)); + } else { + db_file = name; + } + + base (db_file); + + debug ("Using database file %s", db_file); + + this.exec ("PRAGMA synchronous = OFF"); + this.exec ("PRAGMA temp_store = MEMORY"); + this.exec ("PRAGMA count_changes = OFF"); + + this.db.create_function ("contains", + 2, + Sqlite.UTF8, + null, + Database.utf8_contains, + null, + null); + + this.db.create_collation ("CASEFOLD", + Sqlite.UTF8, + Database.utf8_collate); + } + + /** + * SQL query function. + * + * Use for all queries that return a result set. + * + * @param sql The SQL query to run. + * @param args Values to bind in the SQL query or null. + * @throws DatabaseError if the underlying SQLite operation fails. + */ + public Cursor exec_cursor (string sql, + GLib.Value[]? arguments = null) + throws DatabaseError { + return new Cursor (this.db, sql, arguments); + } + + /** + * Simple SQL query execution function. + * + * Use for all queries that don't return anything. + * + * @param sql The SQL query to run. + * @param args Values to bind in the SQL query or null. + * @throws DatabaseError if the underlying SQLite operation fails. + */ + public void exec (string sql, + GLib.Value[]? arguments = null) + throws DatabaseError { + if (arguments == null) { + this.throw_if_code_is_error (this.db.exec (sql)); + + return; + } + + var cursor = this.exec_cursor (sql, arguments); + while (cursor.has_next ()) { + cursor.next (); + } + } + + /** + * Execute a SQL query that returns a single number. + * + * @param sql The SQL query to run. + * @param args Values to bind in the SQL query or null. + * @return The contents of the first row's column as an int. + * @throws DatabaseError if the underlying SQLite operation fails. + */ + public int query_value (string sql, + GLib.Value[]? args = null) + throws DatabaseError { + var cursor = this.exec_cursor (sql, args); + var statement = cursor.next (); + return statement->column_int (0); + } + + /** + * Analyze triggers of database + */ + public void analyze () { + this.db.exec ("ANALYZE"); + } + + /** + * Start a transaction + */ + public void begin () throws DatabaseError { + this.exec ("BEGIN"); + } + + /** + * Commit a transaction + */ + public void commit () throws DatabaseError { + this.exec ("COMMIT"); + } + + /** + * Rollback a transaction + */ + public void rollback () { + try { + this.exec ("ROLLBACK"); + } catch (DatabaseError error) { + critical (_("Failed to roll back transaction: %s"), + error.message); + } + } +} |