luau/VM/src/ldblib.cpp

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// This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
// This code is based on Lua 5.x implementation licensed under MIT License; see lua_LICENSE.txt for details
#include "lualib.h"
#include "lvm.h"
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
static lua_State* getthread(lua_State* L, int* arg)
{
if (lua_isthread(L, 1))
{
*arg = 1;
return lua_tothread(L, 1);
}
else
{
*arg = 0;
return L;
}
}
static int db_info(lua_State* L)
{
int arg;
lua_State* L1 = getthread(L, &arg);
// If L1 != L, L1 can be in any state, and therefore there are no guarantees about its stack space
if (L != L1)
lua_rawcheckstack(L1, 1); // for 'f' option
int level;
if (lua_isnumber(L, arg + 1))
{
level = (int)lua_tointeger(L, arg + 1);
luaL_argcheck(L, level >= 0, arg + 1, "level can't be negative");
}
else if (arg == 0 && lua_isfunction(L, 1))
{
// convert absolute index to relative index
level = -lua_gettop(L);
}
else
luaL_argerror(L, arg + 1, "function or level expected");
const char* options = luaL_checkstring(L, arg + 2);
lua_Debug ar;
if (!lua_getinfo(L1, level, options, &ar))
return 0;
int results = 0;
bool occurs[26] = {};
for (const char* it = options; *it; ++it)
{
if (unsigned(*it - 'a') < 26)
{
if (occurs[*it - 'a'])
luaL_argerror(L, arg + 2, "duplicate option");
occurs[*it - 'a'] = true;
}
switch (*it)
{
case 's':
lua_pushstring(L, ar.short_src);
results++;
break;
case 'l':
lua_pushinteger(L, ar.currentline);
results++;
break;
case 'n':
lua_pushstring(L, ar.name ? ar.name : "");
results++;
break;
case 'f':
if (L1 == L)
lua_pushvalue(L, -1 - results); /* function is right before results */
else
lua_xmove(L1, L, 1); /* function is at top of L1 */
results++;
break;
case 'a':
lua_pushinteger(L, ar.nparams);
lua_pushboolean(L, ar.isvararg);
results += 2;
break;
default:
luaL_argerror(L, arg + 2, "invalid option");
}
}
return results;
}
static int db_traceback(lua_State* L)
{
int arg;
lua_State* L1 = getthread(L, &arg);
const char* msg = luaL_optstring(L, arg + 1, NULL);
int level = luaL_optinteger(L, arg + 2, (L == L1) ? 1 : 0);
luaL_argcheck(L, level >= 0, arg + 2, "level can't be negative");
luaL_Buffer buf;
luaL_buffinit(L, &buf);
if (msg)
{
luaL_addstring(&buf, msg);
luaL_addstring(&buf, "\n");
}
lua_Debug ar;
for (int i = level; lua_getinfo(L1, i, "sln", &ar); ++i)
{
if (strcmp(ar.what, "C") == 0)
continue;
if (ar.source)
luaL_addstring(&buf, ar.short_src);
if (ar.currentline > 0)
{
char line[32];
#ifdef _MSC_VER
_itoa(ar.currentline, line, 10); // 5x faster than sprintf
#else
sprintf(line, "%d", ar.currentline);
#endif
luaL_addchar(&buf, ':');
luaL_addstring(&buf, line);
}
if (ar.name)
{
luaL_addstring(&buf, " function ");
luaL_addstring(&buf, ar.name);
}
luaL_addchar(&buf, '\n');
}
luaL_pushresult(&buf);
return 1;
}
static const luaL_Reg dblib[] = {
{"info", db_info},
{"traceback", db_traceback},
{NULL, NULL},
};
int luaopen_debug(lua_State* L)
{
luaL_register(L, LUA_DBLIBNAME, dblib);
return 1;
}