text: /*
  ** Debug library.
  ** Copyright (C) 2005-2016 Mike Pall. See Copyright Notice in luajit.h
  **
  ** Major portions taken verbatim or adapted from the Lua interpreter.
  ** Copyright (C) 1994-2008 Lua.org, PUC-Rio. See Copyright Notice in lua.h
  */
  
  #define lib_debug_c
  #define LUA_LIB
  
  #include "lua.h"
  #include "lauxlib.h"
  #include "lualib.h"
  
  #include "lj_obj.h"
  #include "lj_gc.h"
  #include "lj_err.h"
  #include "lj_debug.h"
  #include "lj_lib.h"
  
  /* ------------------------------------------------------------------------ */
  
  #define LJLIB_MODULE_debug
  
  LJLIB_CF(debug_getregistry)
  {
    copyTV(L, L->top++, registry(L));
    return 1;
  }
  
  LJLIB_CF(debug_getmetatable)	LJLIB_REC(.)
  {
    lj_lib_checkany(L, 1);
    if (!lua_getmetatable(L, 1)) {
      setnilV(L->top-1);
    }
    return 1;
  }
  
  LJLIB_CF(debug_setmetatable)
  {
    lj_lib_checktabornil(L, 2);
    L->top = L->base+2;
    lua_setmetatable(L, 1);
  #if !LJ_52
    setboolV(L->top-1, 1);
  #endif
    return 1;
  }
  
  LJLIB_CF(debug_getfenv)
  {
    lj_lib_checkany(L, 1);
    lua_getfenv(L, 1);
    return 1;
  }
  
  LJLIB_CF(debug_setfenv)
  {
    lj_lib_checktab(L, 2);
    L->top = L->base+2;
    if (!lua_setfenv(L, 1))
      lj_err_caller(L, LJ_ERR_SETFENV);
    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 void settabsb(lua_State *L, const char *i, int v)
  {
    lua_pushboolean(L, v);
    lua_setfield(L, -2, i);
  }
  
  static lua_State *getthread(lua_State *L, int *arg)
  {
    if (L->base < L->top && tvisthread(L->base)) {
      *arg = 1;
      return threadV(L->base);
    } 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);
  }
  
  LJLIB_CF(debug_getinfo)
  {
    lj_Debug ar;
    int arg, opt_f = 0, opt_L = 0;
    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), (lua_Debug *)&ar)) {
        setnilV(L->top-1);
        return 1;
      }
    } else if (L->base+arg < L->top && tvisfunc(L->base+arg)) {
      options = lua_pushfstring(L, ">%s", options);
      setfuncV(L1, L1->top++, funcV(L->base+arg));
    } else {
      lj_err_arg(L, arg+1, LJ_ERR_NOFUNCL);
    }
    if (!lj_debug_getinfo(L1, options, &ar, 1))
      lj_err_arg(L, arg+2, LJ_ERR_INVOPT);
    lua_createtable(L, 0, 16);  /* Create result table. */
    for (; *options; options++) {
      switch (*options) {
      case '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);
        break;
      case 'l':
        settabsi(L, "currentline", ar.currentline);
        break;
      case 'u':
        settabsi(L, "nups", ar.nups);
        settabsi(L, "nparams", ar.nparams);
        settabsb(L, "isvararg", ar.isvararg);
        break;
      case 'n':
        settabss(L, "name", ar.name);
        settabss(L, "namewhat", ar.namewhat);
        break;
      case 'f': opt_f = 1; break;
      case 'L': opt_L = 1; break;
      default: break;
      }
    }
    if (opt_L) treatstackoption(L, L1, "activelines");
    if (opt_f) treatstackoption(L, L1, "func");
    return 1;  /* Return result table. */
  }
  
  LJLIB_CF(debug_getlocal)
  {
    int arg;
    lua_State *L1 = getthread(L, &arg);
    lua_Debug ar;
    const char *name;
    int slot = lj_lib_checkint(L, arg+2);
    if (tvisfunc(L->base+arg)) {
      L->top = L->base+arg+1;
      lua_pushstring(L, lua_getlocal(L, NULL, slot));
      return 1;
    }
    if (!lua_getstack(L1, lj_lib_checkint(L, arg+1), &ar))
      lj_err_arg(L, arg+1, LJ_ERR_LVLRNG);
    name = lua_getlocal(L1, &ar, slot);
    if (name) {
      lua_xmove(L1, L, 1);
      lua_pushstring(L, name);
      lua_pushvalue(L, -2);
      return 2;
    } else {
      setnilV(L->top-1);
      return 1;
    }
  }
  
  LJLIB_CF(debug_setlocal)
  {
    int arg;
    lua_State *L1 = getthread(L, &arg);
    lua_Debug ar;
    TValue *tv;
    if (!lua_getstack(L1, lj_lib_checkint(L, arg+1), &ar))
      lj_err_arg(L, arg+1, LJ_ERR_LVLRNG);
    tv = lj_lib_checkany(L, arg+3);
    copyTV(L1, L1->top++, tv);
    lua_pushstring(L, lua_setlocal(L1, &ar, lj_lib_checkint(L, arg+2)));
    return 1;
  }
  
  static int debug_getupvalue(lua_State *L, int get)
  {
    int32_t n = lj_lib_checkint(L, 2);
    const char *name;
    lj_lib_checkfunc(L, 1);
    name = get ? lua_getupvalue(L, 1, n) : lua_setupvalue(L, 1, n);
    if (name) {
      lua_pushstring(L, name);
      if (!get) return 1;
      copyTV(L, L->top, L->top-2);
      L->top++;
      return 2;
    }
    return 0;
  }
  
  LJLIB_CF(debug_getupvalue)
  {
    return debug_getupvalue(L, 1);
  }
  
  LJLIB_CF(debug_setupvalue)
  {
    lj_lib_checkany(L, 3);
    return debug_getupvalue(L, 0);
  }
  
  LJLIB_CF(debug_upvalueid)
  {
    GCfunc *fn = lj_lib_checkfunc(L, 1);
    int32_t n = lj_lib_checkint(L, 2) - 1;
    if ((uint32_t)n >= fn->l.nupvalues)
      lj_err_arg(L, 2, LJ_ERR_IDXRNG);
    setlightudV(L->top-1, isluafunc(fn) ? (void *)gcref(fn->l.uvptr[n]) :
  					(void *)&fn->c.upvalue[n]);
    return 1;
  }
  
  LJLIB_CF(debug_upvaluejoin)
  {
    GCfunc *fn[2];
    GCRef *p[2];
    int i;
    for (i = 0; i < 2; i++) {
      int32_t n;
      fn[i] = lj_lib_checkfunc(L, 2*i+1);
      if (!isluafunc(fn[i]))
        lj_err_arg(L, 2*i+1, LJ_ERR_NOLFUNC);
      n = lj_lib_checkint(L, 2*i+2) - 1;
      if ((uint32_t)n >= fn[i]->l.nupvalues)
        lj_err_arg(L, 2*i+2, LJ_ERR_IDXRNG);
      p[i] = &fn[i]->l.uvptr[n];
    }
    setgcrefr(*p[0], *p[1]);
    lj_gc_objbarrier(L, fn[0], gcref(*p[1]));
    return 0;
  }
  
  #if LJ_52
  LJLIB_CF(debug_getuservalue)
  {
    TValue *o = L->base;
    if (o < L->top && tvisudata(o))
      settabV(L, o, tabref(udataV(o)->env));
    else
      setnilV(o);
    L->top = o+1;
    return 1;
  }
  
  LJLIB_CF(debug_setuservalue)
  {
    TValue *o = L->base;
    if (!(o < L->top && tvisudata(o)))
      lj_err_argt(L, 1, LUA_TUSERDATA);
    if (!(o+1 < L->top && tvistab(o+1)))
      lj_err_argt(L, 2, LUA_TTABLE);
    L->top = o+2;
    lua_setfenv(L, 1);
    return 1;
  }
  #endif
  
  /* ------------------------------------------------------------------------ */
  
  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);
    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_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;
  }
  
  LJLIB_CF(debug_sethook)
  {
    int arg, mask, count;
    lua_Hook func;
    (void)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);
    }
    lua_pushlightuserdata(L, (void *)&KEY_HOOK);
    lua_pushvalue(L, arg+1);
    lua_rawset(L, LUA_REGISTRYINDEX);
    lua_sethook(L, func, mask, count);
    return 0;
  }
  
  LJLIB_CF(debug_gethook)
  {
    char buff[5];
    int mask = lua_gethookmask(L);
    lua_Hook hook = lua_gethook(L);
    if (hook != NULL && hook != hookf) {  /* external hook? */
      lua_pushliteral(L, "external hook");
    } else {
      lua_pushlightuserdata(L, (void *)&KEY_HOOK);
      lua_rawget(L, LUA_REGISTRYINDEX);   /* get hook */
    }
    lua_pushstring(L, unmakemask(mask, buff));
    lua_pushinteger(L, lua_gethookcount(L));
    return 3;
  }
  
  /* ------------------------------------------------------------------------ */
  
  LJLIB_CF(debug_debug)
  {
    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 */
  
  LJLIB_CF(debug_traceback)
  {
    int arg;
    lua_State *L1 = getthread(L, &arg);
    const char *msg = lua_tostring(L, arg+1);
    if (msg == NULL && L->top > L->base+arg)
      L->top = L->base+arg+1;
    else
      luaL_traceback(L, L1, msg, lj_lib_optint(L, arg+2, (L == L1)));
    return 1;
  }
  
  /* ------------------------------------------------------------------------ */
  
  #include "lj_libdef.h"
  
  LUALIB_API int luaopen_debug(lua_State *L)
  {
    LJ_LIB_REG(L, LUA_DBLIBNAME, debug);
    return 1;
  }
  
  