From Balint Reczey

Fix for https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=2453

The patch fixes the problem by extending the original "outstanding stuff"
approach.

Now the pointer itself won't be NULLified, instead we track the pointers with
their expiry state in structs in the outstanding_stuff list.
The Lua objects refers to those structs instead of the actual pointers and
checks the expiry state of the pointers before accessing them.
The pointers are marked expired when the dissection of the frame is finished
and the allocated struct is freed by Lua's garbage collector.

If the garbage collector hits the struct when it holds a not expired pointer,
it marks it as expired (that means we don't have any object in Lua referring to
the pointer) and the struct will be freed at the end of the dissection of the
frame.

this is for the 1.0 branch


svn path=/trunk/; revision=25845

1 files changed, 43 insertions, 10 deletions

diff --git a/epan/wslua/wslua.h b/epan/wslua/wslua.h
index 537a5fb626..f6eafe1b69 100644
--- a/epan/wslua/wslua.h
+++ b/epan/wslua/wslua.h
@@ -5,6 +5,7 @@
  *
  * (c) 2006, Luis E. Garcia Ontanon <luis.ontanon@gmail.com>
  * (c) 2007, Tamas Regos <tamas.regos@ericsson.com>
+ * (c) 2008, Balint Reczey <balint.reczey@ericsson.com>
  *
  * $Id$
  *
@@ -59,8 +60,18 @@
 #define WSLUA_INIT_ROUTINES "init_routines"
 #define LOG_DOMAIN_LUA "wslua"
 
+struct _wslua_tvb {
+    tvbuff_t* ws_tvb;
+    gboolean expired;
+};
+
+struct _wslua_pinfo {
+    packet_info* ws_pinfo;
+    gboolean expired;
+};
+
 struct _wslua_tvbrange {
-    tvbuff_t* tvb;
+    struct _wslua_tvb* tvb;
     int offset;
     int len;
 };
@@ -139,11 +150,19 @@ struct _wslua_distbl_t {
 struct _wslua_col_info {
     column_info* cinfo;
     gint col;
+    gboolean expired;
+};
+
+struct _wslua_cols {
+    column_info* cinfo;
+    gboolean expired;
 };
 
 struct _wslua_treeitem {
 	proto_item* item;
 	proto_tree* tree;
+    	gboolean expired;
+	
 };
 
 typedef void (*tap_extractor_t)(lua_State*,const void*);
@@ -183,11 +202,11 @@ typedef struct _wslua_proto_t* Proto;
 typedef struct _wslua_distbl_t* DissectorTable;
 typedef dissector_handle_t Dissector;
 typedef GByteArray* ByteArray;
-typedef tvbuff_t* Tvb;
+typedef struct _wslua_tvb* Tvb;
 typedef struct _wslua_tvbrange* TvbRange; 
 typedef struct _wslua_col_info* Column;
-typedef column_info* Columns;
-typedef packet_info* Pinfo;
+typedef struct _wslua_cols* Columns;
+typedef struct _wslua_pinfo* Pinfo;
 typedef struct _wslua_treeitem* TreeItem;
 typedef address* Address;
 typedef header_field_info** Field;
@@ -307,6 +326,18 @@ typedef int dummy##C
 #define NOP
 #define FAIL_ON_NULL(s) if (! *p) luaL_argerror(L,index,s)
 
+/* Clears or marks references that connects Lua to Wireshark structures */
+#define CLEAR_OUTSTANDING(C, marker, marker_val) void clear_outstanding_##C(void) { \
+    while (outstanding_##C->len) { \
+        C p = (C)g_ptr_array_remove_index_fast(outstanding_##C,0); \
+        if (p) { \
+            if (p->marker != marker_val) \
+                p->marker = marker_val; \
+            else \
+                g_free(p); \
+        } \
+    } \
+} 
 
 
 #define WSLUA_CLASS_DECLARE(C) \
@@ -341,14 +372,16 @@ extern void lua_prime_all_fields(proto_tree* tree);
 
 extern int Proto_commit(lua_State* L);
 
-extern void* push_Tvb(lua_State* L, Tvb tvb);
-extern void clear_outstanding_tvbs(void);
+extern Tvb* push_Tvb(lua_State* L, tvbuff_t* tvb);
+extern void clear_outstanding_Tvb(void);
 
-extern void* push_Pinfo(lua_State* L, Pinfo p);
-extern void clear_outstanding_pinfos(void);
+extern Pinfo* push_Pinfo(lua_State* L, packet_info* p);
+extern void clear_outstanding_Pinfo(void);
+extern void clear_outstanding_Column(void);
+extern void clear_outstanding_Columns(void);
 
-extern void* push_TreeItem(lua_State* L, TreeItem ti);
-extern void clear_outstanding_trees(void);
+extern TreeItem* push_TreeItem(lua_State* L, TreeItem ti);
+extern void clear_outstanding_TreeItem(void);
 
 extern void wslua_print_stack(char* s, lua_State* L);