fixed filenames issues in session XML files

examples/hello_proof/why3session.xml

 <?xml version="1.0" encoding="UTF-8"?>
-<!DOCTYPE why3session SYSTEM "/users/demons/melquion/src/why3/share/why3session.dtd">
+<!DOCTYPE why3session SYSTEM "/usr/local/share/why3/why3session.dtd">
 <why3session
- name="./hello_proof/why3session.xml" shape_version="2">
+ shape_version="2">
  <prover
   id="0"
   name="Alt-Ergo"
@@ -9,7 +9,7 @@
  <prover
   id="1"
   name="Coq"
-  version="8.3pl4"/>
+  version="8.3pl3"/>
  <prover
   id="2"
   name="Simplify"
@@ -17,10 +17,10 @@
  <file
   name="../hello_proof.why"
   verified="false"
-  expanded="false">
+  expanded="true">
   <theory
    name="HelloProof"
-   locfile="./hello_proof/../hello_proof.why"
+   locfile="../hello_proof.why"
    loclnum="1" loccnumb="7" loccnume="17"
    verified="false"
    expanded="true">
@@ -28,7 +28,7 @@
     name="My very first Why3 theory"/>
    <goal
     name="G1"
-    locfile="./hello_proof/../hello_proof.why"
+    locfile="../hello_proof.why"
     loclnum="3" loccnumb="7" loccnume="9"
     sum="4daf9675e70ee6481b1153fe95f7c750"
     proved="true"
@@ -45,7 +45,7 @@
    </goal>
    <goal
     name="G2"
-    locfile="./hello_proof/../hello_proof.why"
+    locfile="../hello_proof.why"
     loclnum="5" loccnumb="7" loccnume="9"
     sum="b16d2c9608c416dc0059ba3e95264abe"
     proved="false"
@@ -73,7 +73,7 @@
      expanded="true">
      <goal
       name="G2.1"
-      locfile="./hello_proof/../hello_proof.why"
+      locfile="../hello_proof.why"
       loclnum="5" loccnumb="7" loccnume="9"
       sum="b84cad55140412a1b6f988cba7a0ebd1"
       proved="false"
@@ -88,26 +88,26 @@
        <result status="unknown" time="0.00"/>
       </proof>
       <proof
-       prover="2"
+       prover="1"
        timelimit="4"
        memlimit="0"
+       edited="hello_proof_HelloProof_G2_1.v"
        obsolete="false"
        archived="false">
-       <result status="unknown" time="0.00"/>
+       <result status="unknown" time="0.76"/>
       </proof>
       <proof
-       prover="1"
+       prover="2"
        timelimit="4"
        memlimit="0"
-       edited="hello_proof_HelloProof_G2_1.v"
        obsolete="false"
        archived="false">
-       <result status="unknown" time="0.49"/>
+       <result status="unknown" time="0.00"/>
       </proof>
      </goal>
      <goal
       name="G2.2"
-      locfile="./hello_proof/../hello_proof.why"
+      locfile="../hello_proof.why"
       loclnum="5" loccnumb="7" loccnume="9"
       sum="fdf75c799e5829c6e57c69e76f88886a"
       proved="true"
@@ -134,7 +134,7 @@
    </goal>
    <goal
     name="G3"
-    locfile="./hello_proof/../hello_proof.why"
+    locfile="../hello_proof.why"
     loclnum="9" loccnumb="7" loccnume="9"
     sum="e2296194dcf5f95896f599f6da2c8adf"
     proved="true"

share/why3session.dtd

 <!ELEMENT why3session (prover*, file*)>
-<!ATTLIST why3session name CDATA #REQUIRED>
 <!ATTLIST why3session shape_version CDATA #IMPLIED>
 
 <!ELEMENT prover EMPTY>

src/session/session.ml

@@ -461,6 +461,7 @@ let goal_expl g = Util.def_option g.goal_name.Ident.id_string g.goal_expl
 open Format
 
 let db_filename = "why3session.xml"
+let session_dir_for_save = ref "."
 
 let save_string fmt s =
   for i=0 to String.length s - 1 do
@@ -518,6 +519,7 @@ let save_ident fmt id =
     | None -> ()
     | Some loc ->
       let file,lnum,cnumb,cnume = Loc.get loc in
+      let file = Sysutil.relativize_filename !session_dir_for_save file in
       fprintf fmt
         "@ locfile=\"%a\"@ loclnum=\"%i\" loccnumb=\"%i\" loccnume=\"%i\""
         save_string file lnum cnumb cnume
@@ -650,8 +652,13 @@ let save fname config session =
   fprintf fmt "<!DOCTYPE why3session SYSTEM \"%a\">@\n"
     save_string (Filename.concat (Whyconf.datadir (Whyconf.get_main config))
                    "why3session.dtd");
+(*
+  let rel_file = Sysutil.relativize_filename !session_dir_for_save fname in
   fprintf fmt "@[<v 1><why3session@ name=\"%a\" shape_version=\"%d\">"
-    save_string fname session.session_shape_version;
+    save_string rel_file session.session_shape_version;
+*)
+  fprintf fmt "@[<v 1><why3session shape_version=\"%d\">"
+    session.session_shape_version;
   let provers,_ = Sprover.fold (save_prover fmt) (get_used_provers session)
     (Mprover.empty,0) in
   PHstr.iter (save_file provers fmt) session.session_files;
@@ -662,6 +669,7 @@ let save fname config session =
 let save_session config session =
   let f = Filename.concat session.session_dir db_filename in
   Sysutil.backup_file f;
+  session_dir_for_save := session.session_dir;
   save f config session
 
 (*******************************)