License upgrade to GPL version 3 or later

[empserver] / src / lib / common / file.c

diff --git a/src/lib/common/file.c b/src/lib/common/file.c
index af02cf1842024120e8d3f4a3279e126522061fb6..804f8b28b429453a1163598e656b372766fe297b 100644 (file)
--- a/src/lib/common/file.c
+++ b/src/lib/common/file.c
@@ -1,11 +1,11 @@
 /*
  *  Empire - A multi-player, client/server Internet based war game.
- *  Copyright (C) 1986-2009, Dave Pare, Jeff Bailey, Thomas Ruschak,
- *                           Ken Stevens, Steve McClure
+ *  Copyright (C) 1986-2011, Dave Pare, Jeff Bailey, Thomas Ruschak,
+ *                Ken Stevens, Steve McClure, Markus Armbruster
  *
- *  This program is free software; you can redistribute it and/or modify
+ *  Empire 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
+ *  the Free Software Foundation, either version 3 of the License, or
  *  (at your option) any later version.
  *
  *  This program is distributed in the hope that it will be useful,
@@ -14,8 +14,7 @@
  *  GNU General Public License for more details.
  *
  *  You should have received a copy of the GNU General Public License
- *  along with this program; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  *  ---
  *
@@ -57,9 +56,12 @@ static int do_read(struct empfile *, void *, int, int);
 static int do_write(struct empfile *, void *, int, int);
 static unsigned get_seqno(struct empfile *, int);
 static void new_seqno(struct empfile *, void *);
+static void must_be_fresh(struct empfile *, void *);
 static void do_blank(struct empfile *, void *, int, int);
 static int ef_check(int);
 
+static unsigned ef_generation;
+
 /*
  * Open the file-backed table TYPE (EF_SECTOR, ...).
  * HOW are flags to control operation.  Naturally, immutable flags are
@@ -360,6 +362,7 @@ ef_read(int type, int id, void *into)
        cachep = ep->cache + (id - ep->baseid) * ep->size;
     }
     memcpy(into, cachep, ep->size);
+    ef_mark_fresh(type, into);
 
     if (ep->postread)
        ep->postread(id, into);
@@ -522,9 +525,11 @@ ef_write(int type, int id, void *from)
        if (ep->onresize && ep->onresize(type) < 0)
            return 0;
     }
-    if (id >= ep->baseid && id < ep->baseid + ep->cids)
+    if (id >= ep->baseid && id < ep->baseid + ep->cids) {
        cachep = ep->cache + (id - ep->baseid) * ep->size;
-    else
+       if (cachep != from)
+           must_be_fresh(ep, from);
+    } else
        cachep = NULL;
     if (ep->prewrite)
        ep->prewrite(id, cachep, from);
@@ -603,11 +608,39 @@ new_seqno(struct empfile *ep, void *buf)
     if (!(ep->flags & EFF_TYPED))
        return;
     old_seqno = get_seqno(ep, elt->uid);
-    if (CANT_HAPPEN(old_seqno != elt->seqno))
-       old_seqno = MAX(old_seqno, elt->seqno);
+    CANT_HAPPEN(old_seqno != elt->seqno);
     elt->seqno = old_seqno + 1;
 }
 
+void
+ef_make_stale(void)
+{
+    ef_generation++;
+}
+
+void
+ef_mark_fresh(int type, void *buf)
+{
+    struct empfile *ep;
+
+    if (ef_check(type) < 0)
+       return;
+    ep = &empfile[type];
+    if (!(ep->flags & EFF_TYPED))
+       return;
+    ((struct emptypedstr *)buf)->generation = ef_generation;
+}
+
+static void
+must_be_fresh(struct empfile *ep, void *buf)
+{
+    struct emptypedstr *elt = buf;
+
+    if (!(ep->flags & EFF_TYPED))
+       return;
+    CANT_HAPPEN(elt->generation != (ef_generation & 0xfff));
+}
+
 /*
  * Extend table TYPE by COUNT elements.
  * Any pointers obtained from ef_ptr() become invalid.
@@ -685,6 +718,7 @@ ef_blank(int type, int id, void *buf)
        elt = buf;
        elt->seqno = get_seqno(ep, elt->uid);
     }
+    ef_mark_fresh(type, buf);
 }
 
 /*