[mod_lua] Add Dbh:query_rows

The added method, query_rows, allows the retrieval of rows from a database without the need for a callback function, it fetches the rows and returns 3 arguments as show below.

```
lua
local success, rows, err = dbh:query_rows(sql)
```

This function performs better with large number of rows. Test results below 50k rows returned.

dbh:query(sql, callback) - 0.335949 seconds
dbh:query_rows(sql) - 0.253178 seconds

src/mod/languages/mod_lua/freeswitch.i

@@ -61,6 +61,11 @@
 %include "typemaps.i"
 %apply int *OUTPUT { int *len };
 
+%typemap(out) DbhQueryRowsReturn {
+    SWIG_arg += result;
+}
+
+
 /**
  * tell swig to grok everything defined in these header files and
  * build all sorts of c wrappers and lua shadows of the c wrappers.
@@ -115,6 +120,7 @@ class Dbh {
     bool connected();
     bool test_reactive(char *test_sql, char *drop_sql = NULL, char *reactive_sql = NULL);
     bool query(char *sql, SWIGLUA_FN lua_fun);
+    DbhQueryRowsReturn query_rows(lua_State* L, char *sql);
     int affected_rows();
     char *last_error();
     void clear_error();

src/mod/languages/mod_lua/freeswitch_lua.cpp

@@ -482,6 +482,62 @@ bool Dbh::query(char *sql, SWIGLUA_FN lua_fun)
   return false;
 }
 
+struct query_callback_data {
+    lua_State *L;
+    int stack_index;
+    int *row_num;
+};
+
+int query2_callback(void *pArg, int argc, char **argv, char **columnNames)
+{
+    struct query_callback_data *data = (struct query_callback_data *) pArg;
+    lua_State *tL = data->L;
+    lua_createtable(tL, 0, argc);
+    for (int i = 0; i < argc; i++) {
+        lua_pushstring(tL, argv[i]);
+        lua_setfield(tL, -2, switch_str_nil(columnNames[i]));
+    }
+    lua_rawseti(tL, data->stack_index + 2, (*data->row_num)++);
+    return 0;
+}
+
+DbhQueryRowsReturn Dbh::query_rows(lua_State* L, char *sql)
+{
+    int stack_index = lua_gettop(L);
+    clear_error();
+    lua_pushboolean(L, 0); // result success error: stack_index + 1
+    lua_newtable(L);       // the rows: stack_index + 2
+    lua_pushnil(L);        // error message if any: stack_index + 3
+
+    if (zstr(sql)) {
+        switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "Missing SQL query.\n");
+        lua_pushstring(L, "Missing SQL query.");
+	lua_replace(L, stack_index + 3);
+        return 3;
+    }
+
+    if (dbh) {
+        int index = 1;
+        struct query_callback_data pData = {L, stack_index, &index};
+
+        if (switch_cache_db_execute_sql_callback(dbh, sql, query2_callback, &pData, &err) == SWITCH_STATUS_SUCCESS) {
+            // no errors
+	    lua_pushboolean(L, 1);
+            lua_replace(L, stack_index + 1);
+        } else {
+            lua_pushstring(L, !zstr(err) ? err : "Failed to execute sql query");
+	    lua_replace(L, stack_index + 3);
+        }
+    } else {
+        switch_log_printf(SWITCH_CHANNEL_LOG, SWITCH_LOG_ERROR, "DBH NOT Connected.\n");
+        lua_pushstring(L, "DBH NOT Connected.");
+	lua_replace(L, stack_index + 3);
+    }
+
+    return 3;
+}
+
+
 int Dbh::affected_rows()
 {
   if (dbh) {

src/mod/languages/mod_lua/freeswitch_lua.h

@@ -28,6 +28,7 @@ typedef struct{
 
 #define SWIGLUA_TABLE_GET(fn) {lua_pushvalue(fn.L,fn.idx);}
 
+typedef int DbhQueryRowsReturn;
 
 namespace LUA {
 	class Session:public CoreSession {
@@ -76,6 +77,7 @@ namespace LUA {
       bool connected();
       bool test_reactive(char *test_sql, char *drop_sql = NULL, char *reactive_sql = NULL);
       bool query(char *sql, SWIGLUA_FN lua_fun);
+      DbhQueryRowsReturn query_rows(lua_State* L, char *sql);
       int affected_rows();
       char *last_error();
       void clear_error();