/*

** $Id: ldblib.c,v 1.104.1.3 2008/01/21 13:11:21 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) {

  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;

}