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/*
Minetest
Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "common/c_internal.h"
#include "debug.h"
std::string script_get_backtrace(lua_State *L)
{
std::string s;
lua_getglobal(L, "debug");
if(lua_istable(L, -1)){
lua_getfield(L, -1, "traceback");
if(lua_isfunction(L, -1)) {
lua_call(L, 0, 1);
if(lua_isstring(L, -1)){
s = lua_tostring(L, -1);
}
}
lua_pop(L, 1);
}
lua_pop(L, 1);
return s;
}
int script_error_handler(lua_State *L) {
lua_getglobal(L, "debug");
if (!lua_istable(L, -1)) {
lua_pop(L, 1);
return 1;
}
lua_getfield(L, -1, "traceback");
if (!lua_isfunction(L, -1)) {
lua_pop(L, 2);
return 1;
}
lua_pushvalue(L, 1);
lua_pushinteger(L, 2);
lua_call(L, 2, 1);
return 1;
}
void script_error(lua_State *L)
{
const char *s = lua_tostring(L, -1);
std::string str(s ? s : "");
throw LuaError(NULL, str);
}
// Push the list of callbacks (a lua table).
// Then push nargs arguments.
// Then call this function, which
// - runs the callbacks
// - removes the table and arguments from the lua stack
// - pushes the return value, computed depending on mode
void script_run_callbacks(lua_State *L, int nargs, RunCallbacksMode mode)
{
// Insert the return value into the lua stack, below the table
assert(lua_gettop(L) >= nargs + 1);
lua_pushnil(L);
int rv = lua_gettop(L) - nargs - 1;
lua_insert(L, rv);
// Insert error handler after return value
lua_pushcfunction(L, script_error_handler);
int errorhandler = rv + 1;
lua_insert(L, errorhandler);
// Stack now looks like this:
// ... <return value = nil> <error handler> <table> <arg#1> <arg#2> ... <arg#n>
int table = errorhandler + 1;
int arg = table + 1;
luaL_checktype(L, table, LUA_TTABLE);
// Foreach
lua_pushnil(L);
bool first_loop = true;
while(lua_next(L, table) != 0){
// key at index -2 and value at index -1
luaL_checktype(L, -1, LUA_TFUNCTION);
// Call function
for(int i = 0; i < nargs; i++)
lua_pushvalue(L, arg+i);
if(lua_pcall(L, nargs, 1, errorhandler))
script_error(L);
// Move return value to designated space in stack
// Or pop it
if(first_loop){
// Result of first callback is always moved
lua_replace(L, rv);
first_loop = false;
} else {
// Otherwise, what happens depends on the mode
if(mode == RUN_CALLBACKS_MODE_FIRST)
lua_pop(L, 1);
else if(mode == RUN_CALLBACKS_MODE_LAST)
lua_replace(L, rv);
else if(mode == RUN_CALLBACKS_MODE_AND ||
mode == RUN_CALLBACKS_MODE_AND_SC){
if((bool)lua_toboolean(L, rv) == true &&
(bool)lua_toboolean(L, -1) == false)
lua_replace(L, rv);
else
lua_pop(L, 1);
}
else if(mode == RUN_CALLBACKS_MODE_OR ||
mode == RUN_CALLBACKS_MODE_OR_SC){
if((bool)lua_toboolean(L, rv) == false &&
(bool)lua_toboolean(L, -1) == true)
lua_replace(L, rv);
else
lua_pop(L, 1);
}
else
assert(0);
}
// Handle short circuit modes
if(mode == RUN_CALLBACKS_MODE_AND_SC &&
(bool)lua_toboolean(L, rv) == false)
break;
else if(mode == RUN_CALLBACKS_MODE_OR_SC &&
(bool)lua_toboolean(L, rv) == true)
break;
// value removed, keep key for next iteration
}
// Remove stuff from stack, leaving only the return value
lua_settop(L, rv);
// Fix return value in case no callbacks were called
if(first_loop){
if(mode == RUN_CALLBACKS_MODE_AND ||
mode == RUN_CALLBACKS_MODE_AND_SC){
lua_pop(L, 1);
lua_pushboolean(L, true);
}
else if(mode == RUN_CALLBACKS_MODE_OR ||
mode == RUN_CALLBACKS_MODE_OR_SC){
lua_pop(L, 1);
lua_pushboolean(L, false);
}
}
}
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