/*
** $Id: ldblib.c,v 1.104.1.4 2009/08/04 18:50:18 roberto Exp $
** Interface from Lua to its debug API
** See Copyright Notice in lua.h
*/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define ldblib_c
#define LUA_LIB

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"

static int db_getregistry(lua_State *L)
{
    lua_pushvalue(L, LUA_REGISTRYINDEX);
    return 1;
}

static int db_getmetatable(lua_State *L)
{
    luaL_checkany(L, 1);
    if (!lua_getmetatable(L, 1)) {
        lua_pushnil(L); /* no metatable */
    }
    return 1;
}

static int db_setmetatable(lua_State *L)
{
    int t = lua_type(L, 2);
    luaL_argcheck(L, t == LUA_TNIL || t == LUA_TTABLE, 2,
                  "nil or table expected");
    lua_settop(L, 2);
    lua_pushboolean(L, lua_setmetatable(L, 1));
    return 1;
}

static int db_getfenv(lua_State *L)
{
    luaL_checkany(L, 1);
    lua_getfenv(L, 1);
    return 1;
}

static int db_setfenv(lua_State *L)
{
    luaL_checktype(L, 2, LUA_TTABLE);
    lua_settop(L, 2);
    if (lua_setfenv(L, 1) == 0)
        luaL_error(
            L, LUA_QL("setfenv") " cannot change environment of given object");
    return 1;
}

static void settabss(lua_State *L, const char *i, const char *v)
{
    lua_pushstring(L, v);
    lua_setfield(L, -2, i);
}

static void settabsi(lua_State *L, const char *i, int v)
{
    lua_pushinteger(L, v);
    lua_setfield(L, -2, i);
}

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 void treatstackoption(lua_State *L, lua_State *L1, const char *fname)
{
    if (L == L1) {
        lua_pushvalue(L, -2);
        lua_remove(L, -3);
    }
    else
        lua_xmove(L1, L, 1);
    lua_setfield(L, -2, fname);
}

static int db_getinfo(lua_State *L)
{
    lua_Debug ar;
    int arg;
    lua_State *L1 = getthread(L, &arg);
    const char *options = luaL_optstring(L, arg + 2, "flnSu");
    if (lua_isnumber(L, arg + 1)) {
        if (!lua_getstack(L1, (int)lua_tointeger(L, arg + 1), &ar)) {
            lua_pushnil(L); /* level out of range */
            return 1;
        }
    }
    else if (lua_isfunction(L, arg + 1)) {
        lua_pushfstring(L, ">%s", options);
        options = lua_tostring(L, -1);
        lua_pushvalue(L, arg + 1);
        lua_xmove(L, L1, 1);
    }
    else
        return luaL_argerror(L, arg + 1, "function or level expected");
    if (!lua_getinfo(L1, options, &ar))
        return luaL_argerror(L, arg + 2, "invalid option");
    lua_createtable(L, 0, 2);
    if (strchr(options, 'S')) {
        settabss(L, "source", ar.source);
        settabss(L, "short_src", ar.short_src);
        settabsi(L, "linedefined", ar.linedefined);
        settabsi(L, "lastlinedefined", ar.lastlinedefined);
        settabss(L, "what", ar.what);
    }
    if (strchr(options, 'l'))
        settabsi(L, "currentline", ar.currentline);
    if (strchr(options, 'u'))
        settabsi(L, "nups", ar.nups);
    if (strchr(options, 'n')) {
        settabss(L, "name", ar.name);
        settabss(L, "namewhat", ar.namewhat);
    }
    if (strchr(options, 'L'))
        treatstackoption(L, L1, "activelines");
    if (strchr(options, 'f'))
        treatstackoption(L, L1, "func");
    return 1; /* return table */
}

static int db_getlocal(lua_State *L)
{
    int arg;
    lua_State *L1 = getthread(L, &arg);
    lua_Debug ar;
    const char *name;
    if (!lua_getstack(L1, luaL_checkint(L, arg + 1), &ar)) /* out of range? */
        return luaL_argerror(L, arg + 1, "level out of range");
    name = lua_getlocal(L1, &ar, luaL_checkint(L, arg + 2));
    if (name) {
        lua_xmove(L1, L, 1);
        lua_pushstring(L, name);
        lua_pushvalue(L, -2);
        return 2;
    }
    else {
        lua_pushnil(L);
        return 1;
    }
}

static int db_setlocal(lua_State *L)
{
    int arg;
    lua_State *L1 = getthread(L, &arg);
    lua_Debug ar;
    if (!lua_getstack(L1, luaL_checkint(L, arg + 1), &ar)) /* out of range? */
        return luaL_argerror(L, arg + 1, "level out of range");
    luaL_checkany(L, arg + 3);
    lua_settop(L, arg + 3);
    lua_xmove(L, L1, 1);
    lua_pushstring(L, lua_setlocal(L1, &ar, luaL_checkint(L, arg + 2)));
    return 1;
}

static int auxupvalue(lua_State *L, int get)
{
    const char *name;
    int n = luaL_checkint(L, 2);
    luaL_checktype(L, 1, LUA_TFUNCTION);
    if (lua_iscfunction(L, 1))
        return 0; /* cannot touch C upvalues from Lua */
    name = get ? lua_getupvalue(L, 1, n) : lua_setupvalue(L, 1, n);
    if (name == NULL)
        return 0;
    lua_pushstring(L, name);
    lua_insert(L, -(get + 1));
    return get + 1;
}

static int db_getupvalue(lua_State *L) { return auxupvalue(L, 1); }

static int db_setupvalue(lua_State *L)
{
    luaL_checkany(L, 3);
    return auxupvalue(L, 0);
}

static const char KEY_HOOK = 'h';

static void hookf(lua_State *L, lua_Debug *ar)
{
    static const char *const hooknames[] = {"call", "return", "line", "count",
                                            "tail return"};
    lua_pushlightuserdata(L, (void *)&KEY_HOOK);
    lua_rawget(L, LUA_REGISTRYINDEX);
    lua_pushlightuserdata(L, L);
    lua_rawget(L, -2);
    if (lua_isfunction(L, -1)) {
        lua_pushstring(L, hooknames[(int)ar->event]);
        if (ar->currentline >= 0)
            lua_pushinteger(L, ar->currentline);
        else
            lua_pushnil(L);
        lua_assert(lua_getinfo(L, "lS", ar));
        lua_call(L, 2, 0);
    }
}

static int makemask(const char *smask, int count)
{
    int mask = 0;
    if (strchr(smask, 'c'))
        mask |= LUA_MASKCALL;
    if (strchr(smask, 'r'))
        mask |= LUA_MASKRET;
    if (strchr(smask, 'l'))
        mask |= LUA_MASKLINE;
    if (count > 0)
        mask |= LUA_MASKCOUNT;
    return mask;
}

static char *unmakemask(int mask, char *smask)
{
    int i = 0;
    if (mask & LUA_MASKCALL)
        smask[i++] = 'c';
    if (mask & LUA_MASKRET)
        smask[i++] = 'r';
    if (mask & LUA_MASKLINE)
        smask[i++] = 'l';
    smask[i] = '\0';
    return smask;
}

static void gethooktable(lua_State *L)
{
    lua_pushlightuserdata(L, (void *)&KEY_HOOK);
    lua_rawget(L, LUA_REGISTRYINDEX);
    if (!lua_istable(L, -1)) {
        lua_pop(L, 1);
        lua_createtable(L, 0, 1);
        lua_pushlightuserdata(L, (void *)&KEY_HOOK);
        lua_pushvalue(L, -2);
        lua_rawset(L, LUA_REGISTRYINDEX);
    }
}

static int db_sethook(lua_State *L)
{
    int arg, mask, count;
    lua_Hook func;
    lua_State *L1 = getthread(L, &arg);
    if (lua_isnoneornil(L, arg + 1)) {
        lua_settop(L, arg + 1);
        func = NULL;
        mask = 0;
        count = 0; /* turn off hooks */
    }
    else {
        const char *smask = luaL_checkstring(L, arg + 2);
        luaL_checktype(L, arg + 1, LUA_TFUNCTION);
        count = luaL_optint(L, arg + 3, 0);
        func = hookf;
        mask = makemask(smask, count);
    }
    gethooktable(L);
    lua_pushlightuserdata(L, L1);
    lua_pushvalue(L, arg + 1);
    lua_rawset(L, -3);                  /* set new hook */
    lua_pop(L, 1);                      /* remove hook table */
    lua_sethook(L1, func, mask, count); /* set hooks */
    return 0;
}

static int db_gethook(lua_State *L)
{
    int arg;
    lua_State *L1 = getthread(L, &arg);
    char buff[5];
    int mask = lua_gethookmask(L1);
    lua_Hook hook = lua_gethook(L1);
    if (hook != NULL && hook != hookf) /* external hook? */
        lua_pushliteral(L, "external hook");
    else {
        gethooktable(L);
        lua_pushlightuserdata(L, L1);
        lua_rawget(L, -2); /* get hook */
        lua_remove(L, -2); /* remove hook table */
    }
    lua_pushstring(L, unmakemask(mask, buff));
    lua_pushinteger(L, lua_gethookcount(L1));
    return 3;
}

static int db_debug(lua_State *L)
{
    for (;;) {
        char buffer[250];
        fputs("lua_debug> ", stderr);
        if (fgets(buffer, sizeof(buffer), stdin) == 0 ||
            strcmp(buffer, "cont\n") == 0)
            return 0;
        if (luaL_loadbuffer(L, buffer, strlen(buffer), "=(debug command)") ||
            lua_pcall(L, 0, 0, 0)) {
            fputs(lua_tostring(L, -1), stderr);
            fputs("\n", stderr);
        }
        lua_settop(L, 0); /* remove eventual returns */
    }
}

#define LEVELS1 12 /* size of the first part of the stack */
#define LEVELS2 10 /* size of the second part of the stack */

static int db_errorfb(lua_State *L)
{
    int level;
    int firstpart = 1; /* still before eventual `...' */
    int arg;
    lua_State *L1 = getthread(L, &arg);
    lua_Debug ar;
    if (lua_isnumber(L, arg + 2)) {
        level = (int)lua_tointeger(L, arg + 2);
        lua_pop(L, 1);
    }
    else
        level = (L == L1) ? 1 : 0; /* level 0 may be this own function */
    if (lua_gettop(L) == arg)
        lua_pushliteral(L, "");
    else if (!lua_isstring(L, arg + 1))
        return 1; /* message is not a string */
    else
        lua_pushliteral(L, "\n");
    lua_pushliteral(L, "stack traceback:");
    while (lua_getstack(L1, level++, &ar)) {
        if (level > LEVELS1 && firstpart) {
            /* no more than `LEVELS2' more levels? */
            if (!lua_getstack(L1, level + LEVELS2, &ar))
                level--; /* keep going */
            else {
                lua_pushliteral(L, "\n\t..."); /* too many levels */
                while (lua_getstack(L1, level + LEVELS2,
                                    &ar)) /* find last levels */
                    level++;
            }
            firstpart = 0;
            continue;
        }
        lua_pushliteral(L, "\n\t");
        lua_getinfo(L1, "Snl", &ar);
        lua_pushfstring(L, "%s:", ar.short_src);
        if (ar.currentline > 0)
            lua_pushfstring(L, "%d:", ar.currentline);
        if (*ar.namewhat != '\0') /* is there a name? */
            lua_pushfstring(L, " in function " LUA_QS, ar.name);
        else {
            if (*ar.what == 'm') /* main? */
                lua_pushfstring(L, " in main chunk");
            else if (*ar.what == 'C' || *ar.what == 't')
                lua_pushliteral(L, " ?"); /* C function or tail call */
            else
                lua_pushfstring(L, " in function <%s:%d>", ar.short_src,
                                ar.linedefined);
        }
        lua_concat(L, lua_gettop(L) - arg);
    }
    lua_concat(L, lua_gettop(L) - arg);
    return 1;
}

static const luaL_Reg dblib[] = {{"debug", db_debug},
                                 {"getfenv", db_getfenv},
                                 {"gethook", db_gethook},
                                 {"getinfo", db_getinfo},
                                 {"getlocal", db_getlocal},
                                 {"getregistry", db_getregistry},
                                 {"getmetatable", db_getmetatable},
                                 {"getupvalue", db_getupvalue},
                                 {"setfenv", db_setfenv},
                                 {"sethook", db_sethook},
                                 {"setlocal", db_setlocal},
                                 {"setmetatable", db_setmetatable},
                                 {"setupvalue", db_setupvalue},
                                 {"traceback", db_errorfb},
                                 {NULL, NULL}};

LUALIB_API int luaopen_debug(lua_State *L)
{
    luaL_register(L, LUA_DBLIBNAME, dblib);
    return 1;
}
