1. metadata are no longer stored in .moo files.

[helm.git] / helm / ocaml / library / libraryNoDb.ml

diff --git a/helm/ocaml/library/libraryNoDb.ml b/helm/ocaml/library/libraryNoDb.ml
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+++ b/helm/ocaml/library/libraryNoDb.ml
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+(* Copyright (C) 2005, HELM Team.
+ * 
+ * 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/
+ *)
+
+open Printf
+
+exception Checksum_failure of string
+exception Corrupt_metadata of string
+exception Version_mismatch of string
+
+let magic = 1
+
+type metadata =
+  | Dependency of string  (* baseuri without trailing slash *)
+  | Baseuri of string 
+
+let eq_metadata (m1:metadata) (m2:metadata) = m1 = m2
+
+let marshal_flags = []
+
+(** .metadata file format
+ * - an integer -- magic number -- denoting the version of the dumped data
+ *   structure. Different magic numbers stand for incompatible data structures
+ * - an integer -- checksum -- denoting the hash value (computed with
+ *   Hashtbl.hash) of the string representation of the dumped data structur
+ * - marshalled data: list of metadata
+ *)
+
+let save_metadata ~fname metadata =
+  let oc = open_out fname in
+  let marshalled = Marshal.to_string metadata marshal_flags in
+  let checksum = Hashtbl.hash marshalled in
+  output_binary_int oc magic;
+  output_binary_int oc checksum;
+  output_string oc marshalled;
+  close_out oc
+
+let load_metadata ~fname =
+  let ic = open_in fname in
+  HExtlib.finally
+    (fun () -> close_in ic)
+    (fun () ->
+      try
+        let file_magic = input_binary_int ic in
+        if file_magic <> magic then raise (Version_mismatch fname);
+        let file_checksum = input_binary_int ic in
+        let marshalled = HExtlib.input_all ic in
+        let checksum = Hashtbl.hash marshalled in
+        if checksum <> file_checksum then raise (Checksum_failure fname);
+        let (metadata:metadata list) = Marshal.from_string marshalled 0 in
+        metadata
+      with End_of_file -> raise (Corrupt_metadata fname))
+    ()
+