+(*
+ * Copyright (C) 2003-2004:
+ * Stefano Zacchiroli <zack@cs.unibo.it>
+ * for the HELM Team http://helm.cs.unibo.it/
+ *
+ * This file is part of HELM, an Hypertextual, Electronic
+ * Library of Mathematics, developed at the Computer Science
+ * Department, University of Bologna, Italy.
+ *
+ * HELM is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * HELM 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with HELM; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+ * MA 02111-1307, USA.
+ *
+ * For details, see the HELM World-Wide-Web page,
+ * http://helm.cs.unibo.it/
+ *)
+
+exception Key_already_in of string;;
+exception Key_not_found of string;;
+
+class map dbname =
+ let perm = 420 in (* permission 644 in decimal notation *)
+ let open_dbm () = Dbm.opendbm dbname [ Dbm.Dbm_rdwr; Dbm.Dbm_create ] perm in
+
+ object (self)
+
+ inherit ThreadSafe.threadSafe
+
+ val mutable db = open_dbm ()
+
+ (*initializer Gc.finalise Dbm.close db (* close db on GC *)*)
+
+ method add key value =
+ self#doWriter (lazy (
+ try
+ Dbm.add db key value
+ with Dbm.Dbm_error "Entry already exists" -> raise (Key_already_in key)
+ ))
+
+ method replace key value =
+ self#doWriter (lazy (
+ Dbm.replace db key value
+ ))
+
+ method remove key =
+ self#doWriter (lazy (
+ try
+ Dbm.remove db key
+ with Dbm.Dbm_error "dbm_delete" -> raise (Key_not_found key)
+ ))
+
+ method resolve key =
+ self#doReader (lazy (
+ try Dbm.find db key with Not_found -> raise (Key_not_found key)
+ ))
+
+ method iter (f: string -> string -> unit) =
+ self#doReader (lazy (
+ Dbm.iter f db
+ ))
+
+ method sync =
+ self#doWriter (lazy (
+ Dbm.close db;
+ db <- open_dbm ()
+ ))
+
+ method clear =
+ self#doWriter (lazy (
+ Dbm.close db;
+ List.iter
+ (fun ext ->
+ let file = dbname ^ ext in
+ if Sys.file_exists file then Sys.remove file)
+ [".dir"; ".pag"; ".db"];
+ db <- open_dbm ()
+ ))
+
+ method close =
+ self#doWriter (lazy (
+ Dbm.close db
+ ))
+
+ end
+