LUA API improvements

1. Add col_set_fence() equivalent
2. Update __tostring function to actually return column text

From Hadriel Kaplan, bug 8295 (https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=8295)

svn path=/trunk/; revision=47882

epan/column-utils.c

@@ -165,6 +165,26 @@ col_set_fence(column_info *cinfo, const gint el)
   }
 }
 
+/* Gets the text of a column */
+const gchar *
+col_get_text(column_info *cinfo, const gint el)
+{
+  int i;
+  const gchar* text = NULL;
+
+  if (!(cinfo && (cinfo)->col_first[el] >= 0)) {
+    return NULL;
+  }
+
+  for (i = cinfo->col_first[el]; i <= cinfo->col_last[el]; i++) {
+    if (cinfo->fmt_matx[i][el]) {
+      text = (cinfo->col_data[i]);
+    }
+  }
+  return text;
+}
+
+
 /* Use this to clear out a column, especially if you're going to be
    appending to it later; at least on some platforms, it's more
    efficient than using "col_add_str()" with a null string, and

epan/column-utils.h

@@ -117,6 +117,15 @@ extern gint	check_col(column_info *cinfo, const gint col);
  */
 extern void	col_set_fence(column_info *cinfo, const gint col);
 
+/** Gets the text of a column element.
+ *
+ * @param cinfo the current packet row
+ * @param col the column to use, e.g. COL_INFO
+ *
+ * @return the text string
+ */
+extern const gchar *col_get_text(column_info *cinfo, const gint col);
+
 /** Clears the text of a column element.
  *
  * @param cinfo the current packet row

epan/wslua/wslua_pinfo.c

@@ -604,17 +604,21 @@ static const gchar*  col_id_to_name(gint id) {
 
 WSLUA_METAMETHOD Column__tostring(lua_State *L) {
     Column c = checkColumn(L,1);
-    const gchar* name;
+    const gchar* text;
 
-    if (!(c)) {
-        return 0;
+    if (!c) {
+        lua_pushstring(L,"(nil)");
+    }
+    else if (!c->cinfo) {
+        text = col_id_to_name(c->col);
+        lua_pushfstring(L, "(%s)", text ? text : "unknown");
+    }
+    else {
+        text = col_get_text(c->cinfo, c->col);
+        lua_pushstring(L, text ? text : "(nil)");
     }
 
-    /* XXX: should return the column's text ! */
-    name = col_id_to_name(c->col);
-    lua_pushstring(L,name ? name : "Unknown Column");
-
-    WSLUA_RETURN(1); /* A string representing the column */
+    WSLUA_RETURN(1); /* The column's string text (in parenthesis if not available) */
 }
 
 static int Column__gc(lua_State* L) {
@@ -691,12 +695,24 @@ WSLUA_METHOD Column_prepend(lua_State *L) {
     return 0;
 }
 
+WSLUA_METHOD Column_fence(lua_State *L) {
+        /* Sets Column text fence, to prevent overwriting */
+    Column c = checkColumn(L,1);
+
+    if (c && c->cinfo)
+        col_set_fence(c->cinfo, c->col);
+
+    return 0;
+}  
+
+
 WSLUA_METHODS Column_methods[] = {
     WSLUA_CLASS_FNREG(Column,clear),
     WSLUA_CLASS_FNREG(Column,set),
     WSLUA_CLASS_FNREG(Column,append),
     WSLUA_CLASS_FNREG(Column,prepend),
     WSLUA_CLASS_FNREG_ALIAS(Column,preppend,prepend),
+    WSLUA_CLASS_FNREG(Column,fence),
     {0,0}
 };