wslua: Fix logger after g6a5e90f2

The Qt log output changes in g6a5e90f2 changed the Qt message handler
to use g_log.  Lua logging already used g_log.  The Qt variant of
funnel logger, which is used by Lua as g_log backend, is currently
using qDebug and this gives recursive calls to g_log and thus an assert.

Rewrite the lua logging to not use g_log.

Change-Id: Icf4f0022a11cb32d2b4f413f76d946f2506e283d
Reviewed-on: https://code.wireshark.org/review/24888
Petri-Dish: Stig Bjørlykke <stig@bjorlykke.org>
Tested-by: Petri Dish Buildbot
Reviewed-by: Anders Broman <a.broman58@gmail.com>

epan/wslua/init_wslua.c

@@ -53,6 +53,7 @@ static lua_State* L = NULL;
 packet_info* lua_pinfo;
 struct _wslua_treeitem* lua_tree;
 tvbuff_t* lua_tvb;
+wslua_logger_t wslua_logger;
 int lua_dissectors_table_ref = LUA_NOREF;
 int lua_heur_dissectors_table_ref = LUA_NOREF;
 
@@ -879,17 +880,11 @@ void wslua_init(register_cb cb, gpointer client_data) {
     if (first_time) {
         ws_lua_ei = ei;
         ws_lua_ei_len = array_length(ei);
-
-        /* set up the logger */
-        g_log_set_handler(LOG_DOMAIN_LUA, (GLogLevelFlags)(G_LOG_LEVEL_CRITICAL|
-                      G_LOG_LEVEL_WARNING|
-                      G_LOG_LEVEL_MESSAGE|
-                      G_LOG_LEVEL_INFO|
-                      G_LOG_LEVEL_DEBUG),
-                      ops ? ops->logger : basic_logger,
-                      NULL);
     }
 
+    /* set up the logger */
+    wslua_logger = ops ? ops->logger : basic_logger;
+
     if (!L) {
         L = lua_newstate(wslua_allocf, NULL);
     }

epan/wslua/wslua.h

@@ -67,6 +67,9 @@
 #define WSLUA_PREFS_CHANGED "prefs_changed"
 #define LOG_DOMAIN_LUA "wslua"
 
+typedef void (*wslua_logger_t)(const gchar *, GLogLevelFlags, const gchar *, gpointer);
+extern wslua_logger_t wslua_logger;
+
 /* type conversion macros - lua_Number is a double, so casting isn't kosher; and
    using Lua's already-available lua_tointeger() and luaL_checkinteger() might be different
    on different machines; so use these instead please! */

epan/wslua/wslua_util.c

@@ -160,7 +160,7 @@ static int wslua_log(lua_State* L, GLogLevelFlags log_level) {
         lua_pop(L, 1);  /* pop result */
     }
 
-    g_log(LOG_DOMAIN_LUA, log_level, "%s\n", str->str);
+    wslua_logger(LOG_DOMAIN_LUA, log_level, "%s\n", str->str);
     g_string_free(str,TRUE);
 
     return 0;