text: /*
  ** Package library.
  ** Copyright (C) 2005-2017 Mike Pall. See Copyright Notice in luajit.h
  **
  ** Major portions taken verbatim or adapted from the Lua interpreter.
  ** Copyright (C) 1994-2012 Lua.org, PUC-Rio. See Copyright Notice in lua.h
  */
  
  #define lib_package_c
  #define LUA_LIB
  
  #include "lua.h"
  #include "lauxlib.h"
  #include "lualib.h"
  
  #include "lj_obj.h"
  #include "lj_err.h"
  #include "lj_lib.h"
  
  /* ------------------------------------------------------------------------ */
  
  /* Error codes for ll_loadfunc. */
  #define PACKAGE_ERR_LIB		1
  #define PACKAGE_ERR_FUNC	2
  #define PACKAGE_ERR_LOAD	3
  
  /* Redefined in platform specific part. */
  #define PACKAGE_LIB_FAIL	"open"
  #define setprogdir(L)		((void)0)
  
  /* Symbol name prefixes. */
  #define SYMPREFIX_CF		"luaopen_%s"
  #define SYMPREFIX_BC		"luaJIT_BC_%s"
  
  #if LJ_TARGET_DLOPEN
  
  #include <dlfcn.h>
  
  static void ll_unloadlib(void *lib)
  {
    dlclose(lib);
  }
  
  static void *ll_load(lua_State *L, const char *path, int gl)
  {
    void *lib = dlopen(path, RTLD_NOW | (gl ? RTLD_GLOBAL : RTLD_LOCAL));
    if (lib == NULL) lua_pushstring(L, dlerror());
    return lib;
  }
  
  static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
  {
    lua_CFunction f = (lua_CFunction)dlsym(lib, sym);
    if (f == NULL) lua_pushstring(L, dlerror());
    return f;
  }
  
  static const char *ll_bcsym(void *lib, const char *sym)
  {
  #if defined(RTLD_DEFAULT)
    if (lib == NULL) lib = RTLD_DEFAULT;
  #elif LJ_TARGET_OSX || LJ_TARGET_BSD
    if (lib == NULL) lib = (void *)(intptr_t)-2;
  #endif
    return (const char *)dlsym(lib, sym);
  }
  
  #elif LJ_TARGET_WINDOWS
  
  #define WIN32_LEAN_AND_MEAN
  #include <windows.h>
  
  #ifndef GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS
  #define GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS  4
  #define GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT  2
  BOOL WINAPI GetModuleHandleExA(DWORD, LPCSTR, HMODULE*);
  #endif
  
  #undef setprogdir
  
  static void setprogdir(lua_State *L)
  {
    char buff[MAX_PATH + 1];
    char *lb;
    DWORD nsize = sizeof(buff);
    DWORD n = GetModuleFileNameA(NULL, buff, nsize);
    if (n == 0 || n == nsize || (lb = strrchr(buff, '\\')) == NULL) {
      luaL_error(L, "unable to get ModuleFileName");
    } else {
      *lb = '\0';
      luaL_gsub(L, lua_tostring(L, -1), LUA_EXECDIR, buff);
      lua_remove(L, -2);  /* remove original string */
    }
  }
  
  static void pusherror(lua_State *L)
  {
    DWORD error = GetLastError();
  #if LJ_TARGET_XBOXONE
    wchar_t wbuffer[128];
    char buffer[128*2];
    if (FormatMessageW(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM,
        NULL, error, 0, wbuffer, sizeof(wbuffer)/sizeof(wchar_t), NULL) &&
        WideCharToMultiByte(CP_ACP, 0, wbuffer, 128, buffer, 128*2, NULL, NULL))
  #else
    char buffer[128];
    if (FormatMessageA(FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_FROM_SYSTEM,
        NULL, error, 0, buffer, sizeof(buffer), NULL))
  #endif
      lua_pushstring(L, buffer);
    else
      lua_pushfstring(L, "system error %d\n", error);
  }
  
  static void ll_unloadlib(void *lib)
  {
    FreeLibrary((HINSTANCE)lib);
  }
  
  static void *ll_load(lua_State *L, const char *path, int gl)
  {
    HINSTANCE lib = LoadLibraryExA(path, NULL, 0);
    if (lib == NULL) pusherror(L);
    UNUSED(gl);
    return lib;
  }
  
  static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
  {
    lua_CFunction f = (lua_CFunction)GetProcAddress((HINSTANCE)lib, sym);
    if (f == NULL) pusherror(L);
    return f;
  }
  
  static const char *ll_bcsym(void *lib, const char *sym)
  {
    if (lib) {
      return (const char *)GetProcAddress((HINSTANCE)lib, sym);
    } else {
      HINSTANCE h = GetModuleHandleA(NULL);
      const char *p = (const char *)GetProcAddress(h, sym);
      if (p == NULL && GetModuleHandleExA(GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS|GET_MODULE_HANDLE_EX_FLAG_UNCHANGED_REFCOUNT,
  					(const char *)ll_bcsym, &h))
        p = (const char *)GetProcAddress(h, sym);
      return p;
    }
  }
  
  #else
  
  #undef PACKAGE_LIB_FAIL
  #define PACKAGE_LIB_FAIL	"absent"
  
  #define DLMSG	"dynamic libraries not enabled; no support for target OS"
  
  static void ll_unloadlib(void *lib)
  {
    UNUSED(lib);
  }
  
  static void *ll_load(lua_State *L, const char *path, int gl)
  {
    UNUSED(path); UNUSED(gl);
    lua_pushliteral(L, DLMSG);
    return NULL;
  }
  
  static lua_CFunction ll_sym(lua_State *L, void *lib, const char *sym)
  {
    UNUSED(lib); UNUSED(sym);
    lua_pushliteral(L, DLMSG);
    return NULL;
  }
  
  static const char *ll_bcsym(void *lib, const char *sym)
  {
    UNUSED(lib); UNUSED(sym);
    return NULL;
  }
  
  #endif
  
  /* ------------------------------------------------------------------------ */
  
  static void **ll_register(lua_State *L, const char *path)
  {
    void **plib;
    lua_pushfstring(L, "LOADLIB: %s", path);
    lua_gettable(L, LUA_REGISTRYINDEX);  /* check library in registry? */
    if (!lua_isnil(L, -1)) {  /* is there an entry? */
      plib = (void **)lua_touserdata(L, -1);
    } else {  /* no entry yet; create one */
      lua_pop(L, 1);
      plib = (void **)lua_newuserdata(L, sizeof(void *));
      *plib = NULL;
      luaL_getmetatable(L, "_LOADLIB");
      lua_setmetatable(L, -2);
      lua_pushfstring(L, "LOADLIB: %s", path);
      lua_pushvalue(L, -2);
      lua_settable(L, LUA_REGISTRYINDEX);
    }
    return plib;
  }
  
  static const char *mksymname(lua_State *L, const char *modname,
  			     const char *prefix)
  {
    const char *funcname;
    const char *mark = strchr(modname, *LUA_IGMARK);
    if (mark) modname = mark + 1;
    funcname = luaL_gsub(L, modname, ".", "_");
    funcname = lua_pushfstring(L, prefix, funcname);
    lua_remove(L, -2);  /* remove 'gsub' result */
    return funcname;
  }
  
  static int ll_loadfunc(lua_State *L, const char *path, const char *name, int r)
  {
    void **reg = ll_register(L, path);
    if (*reg == NULL) *reg = ll_load(L, path, (*name == '*'));
    if (*reg == NULL) {
      return PACKAGE_ERR_LIB;  /* Unable to load library. */
    } else if (*name == '*') {  /* Only load library into global namespace. */
      lua_pushboolean(L, 1);
      return 0;
    } else {
      const char *sym = r ? name : mksymname(L, name, SYMPREFIX_CF);
      lua_CFunction f = ll_sym(L, *reg, sym);
      if (f) {
        lua_pushcfunction(L, f);
        return 0;
      }
      if (!r) {
        const char *bcdata = ll_bcsym(*reg, mksymname(L, name, SYMPREFIX_BC));
        lua_pop(L, 1);
        if (bcdata) {
  	if (luaL_loadbuffer(L, bcdata, LJ_MAX_BUF, name) != 0)
  	  return PACKAGE_ERR_LOAD;
  	return 0;
        }
      }
      return PACKAGE_ERR_FUNC;  /* Unable to find function. */
    }
  }
  
  static int lj_cf_package_loadlib(lua_State *L)
  {
    const char *path = luaL_checkstring(L, 1);
    const char *init = luaL_checkstring(L, 2);
    int st = ll_loadfunc(L, path, init, 1);
    if (st == 0) {  /* no errors? */
      return 1;  /* return the loaded function */
    } else {  /* error; error message is on stack top */
      lua_pushnil(L);
      lua_insert(L, -2);
      lua_pushstring(L, (st == PACKAGE_ERR_LIB) ?  PACKAGE_LIB_FAIL : "init");
      return 3;  /* return nil, error message, and where */
    }
  }
  
  static int lj_cf_package_unloadlib(lua_State *L)
  {
    void **lib = (void **)luaL_checkudata(L, 1, "_LOADLIB");
    if (*lib) ll_unloadlib(*lib);
    *lib = NULL;  /* mark library as closed */
    return 0;
  }
  
  /* ------------------------------------------------------------------------ */
  
  static int readable(const char *filename)
  {
    FILE *f = fopen(filename, "r");  /* try to open file */
    if (f == NULL) return 0;  /* open failed */
    fclose(f);
    return 1;
  }
  
  static const char *pushnexttemplate(lua_State *L, const char *path)
  {
    const char *l;
    while (*path == *LUA_PATHSEP) path++;  /* skip separators */
    if (*path == '\0') return NULL;  /* no more templates */
    l = strchr(path, *LUA_PATHSEP);  /* find next separator */
    if (l == NULL) l = path + strlen(path);
    lua_pushlstring(L, path, (size_t)(l - path));  /* template */
    return l;
  }
  
  static const char *searchpath (lua_State *L, const char *name,
  			       const char *path, const char *sep,
  			       const char *dirsep)
  {
    luaL_Buffer msg;  /* to build error message */
    luaL_buffinit(L, &msg);
    if (*sep != '\0')  /* non-empty separator? */
      name = luaL_gsub(L, name, sep, dirsep);  /* replace it by 'dirsep' */
    while ((path = pushnexttemplate(L, path)) != NULL) {
      const char *filename = luaL_gsub(L, lua_tostring(L, -1),
  				     LUA_PATH_MARK, name);
      lua_remove(L, -2);  /* remove path template */
      if (readable(filename))  /* does file exist and is readable? */
        return filename;  /* return that file name */
      lua_pushfstring(L, "\n\tno file " LUA_QS, filename);
      lua_remove(L, -2);  /* remove file name */
      luaL_addvalue(&msg);  /* concatenate error msg. entry */
    }
    luaL_pushresult(&msg);  /* create error message */
    return NULL;  /* not found */
  }
  
  static int lj_cf_package_searchpath(lua_State *L)
  {
    const char *f = searchpath(L, luaL_checkstring(L, 1),
  				luaL_checkstring(L, 2),
  				luaL_optstring(L, 3, "."),
  				luaL_optstring(L, 4, LUA_DIRSEP));
    if (f != NULL) {
      return 1;
    } else {  /* error message is on top of the stack */
      lua_pushnil(L);
      lua_insert(L, -2);
      return 2;  /* return nil + error message */
    }
  }
  
  static const char *findfile(lua_State *L, const char *name,
  			    const char *pname)
  {
    const char *path;
    lua_getfield(L, LUA_ENVIRONINDEX, pname);
    path = lua_tostring(L, -1);
    if (path == NULL)
      luaL_error(L, LUA_QL("package.%s") " must be a string", pname);
    return searchpath(L, name, path, ".", LUA_DIRSEP);
  }
  
  static void loaderror(lua_State *L, const char *filename)
  {
    luaL_error(L, "error loading module " LUA_QS " from file " LUA_QS ":\n\t%s",
  	     lua_tostring(L, 1), filename, lua_tostring(L, -1));
  }
  
  static int lj_cf_package_loader_lua(lua_State *L)
  {
    const char *filename;
    const char *name = luaL_checkstring(L, 1);
    filename = findfile(L, name, "path");
    if (filename == NULL) return 1;  /* library not found in this path */
    if (luaL_loadfile(L, filename) != 0)
      loaderror(L, filename);
    return 1;  /* library loaded successfully */
  }
  
  static int lj_cf_package_loader_c(lua_State *L)
  {
    const char *name = luaL_checkstring(L, 1);
    const char *filename = findfile(L, name, "cpath");
    if (filename == NULL) return 1;  /* library not found in this path */
    if (ll_loadfunc(L, filename, name, 0) != 0)
      loaderror(L, filename);
    return 1;  /* library loaded successfully */
  }
  
  static int lj_cf_package_loader_croot(lua_State *L)
  {
    const char *filename;
    const char *name = luaL_checkstring(L, 1);
    const char *p = strchr(name, '.');
    int st;
    if (p == NULL) return 0;  /* is root */
    lua_pushlstring(L, name, (size_t)(p - name));
    filename = findfile(L, lua_tostring(L, -1), "cpath");
    if (filename == NULL) return 1;  /* root not found */
    if ((st = ll_loadfunc(L, filename, name, 0)) != 0) {
      if (st != PACKAGE_ERR_FUNC) loaderror(L, filename);  /* real error */
      lua_pushfstring(L, "\n\tno module " LUA_QS " in file " LUA_QS,
  		    name, filename);
      return 1;  /* function not found */
    }
    return 1;
  }
  
  static int lj_cf_package_loader_preload(lua_State *L)
  {
    const char *name = luaL_checkstring(L, 1);
    lua_getfield(L, LUA_ENVIRONINDEX, "preload");
    if (!lua_istable(L, -1))
      luaL_error(L, LUA_QL("package.preload") " must be a table");
    lua_getfield(L, -1, name);
    if (lua_isnil(L, -1)) {  /* Not found? */
      const char *bcname = mksymname(L, name, SYMPREFIX_BC);
      const char *bcdata = ll_bcsym(NULL, bcname);
      if (bcdata == NULL || luaL_loadbuffer(L, bcdata, LJ_MAX_BUF, name) != 0)
        lua_pushfstring(L, "\n\tno field package.preload['%s']", name);
    }
    return 1;
  }
  
  /* ------------------------------------------------------------------------ */
  
  #define sentinel	((void *)0x4004)
  
  static int lj_cf_package_require(lua_State *L)
  {
    const char *name = luaL_checkstring(L, 1);
    int i;
    lua_settop(L, 1);  /* _LOADED table will be at index 2 */
    lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
    lua_getfield(L, 2, name);
    if (lua_toboolean(L, -1)) {  /* is it there? */
      if (lua_touserdata(L, -1) == sentinel)  /* check loops */
        luaL_error(L, "loop or previous error loading module " LUA_QS, name);
      return 1;  /* package is already loaded */
    }
    /* else must load it; iterate over available loaders */
    lua_getfield(L, LUA_ENVIRONINDEX, "loaders");
    if (!lua_istable(L, -1))
      luaL_error(L, LUA_QL("package.loaders") " must be a table");
    lua_pushliteral(L, "");  /* error message accumulator */
    for (i = 1; ; i++) {
      lua_rawgeti(L, -2, i);  /* get a loader */
      if (lua_isnil(L, -1))
        luaL_error(L, "module " LUA_QS " not found:%s",
  		 name, lua_tostring(L, -2));
      lua_pushstring(L, name);
      lua_call(L, 1, 1);  /* call it */
      if (lua_isfunction(L, -1))  /* did it find module? */
        break;  /* module loaded successfully */
      else if (lua_isstring(L, -1))  /* loader returned error message? */
        lua_concat(L, 2);  /* accumulate it */
      else
        lua_pop(L, 1);
    }
    lua_pushlightuserdata(L, sentinel);
    lua_setfield(L, 2, name);  /* _LOADED[name] = sentinel */
    lua_pushstring(L, name);  /* pass name as argument to module */
    lua_call(L, 1, 1);  /* run loaded module */
    if (!lua_isnil(L, -1))  /* non-nil return? */
      lua_setfield(L, 2, name);  /* _LOADED[name] = returned value */
    lua_getfield(L, 2, name);
    if (lua_touserdata(L, -1) == sentinel) {   /* module did not set a value? */
      lua_pushboolean(L, 1);  /* use true as result */
      lua_pushvalue(L, -1);  /* extra copy to be returned */
      lua_setfield(L, 2, name);  /* _LOADED[name] = true */
    }
    lj_lib_checkfpu(L);
    return 1;
  }
  
  /* ------------------------------------------------------------------------ */
  
  static void setfenv(lua_State *L)
  {
    lua_Debug ar;
    if (lua_getstack(L, 1, &ar) == 0 ||
        lua_getinfo(L, "f", &ar) == 0 ||  /* get calling function */
        lua_iscfunction(L, -1))
      luaL_error(L, LUA_QL("module") " not called from a Lua function");
    lua_pushvalue(L, -2);
    lua_setfenv(L, -2);
    lua_pop(L, 1);
  }
  
  static void dooptions(lua_State *L, int n)
  {
    int i;
    for (i = 2; i <= n; i++) {
      lua_pushvalue(L, i);  /* get option (a function) */
      lua_pushvalue(L, -2);  /* module */
      lua_call(L, 1, 0);
    }
  }
  
  static void modinit(lua_State *L, const char *modname)
  {
    const char *dot;
    lua_pushvalue(L, -1);
    lua_setfield(L, -2, "_M");  /* module._M = module */
    lua_pushstring(L, modname);
    lua_setfield(L, -2, "_NAME");
    dot = strrchr(modname, '.');  /* look for last dot in module name */
    if (dot == NULL) dot = modname; else dot++;
    /* set _PACKAGE as package name (full module name minus last part) */
    lua_pushlstring(L, modname, (size_t)(dot - modname));
    lua_setfield(L, -2, "_PACKAGE");
  }
  
  static int lj_cf_package_module(lua_State *L)
  {
    const char *modname = luaL_checkstring(L, 1);
    int loaded = lua_gettop(L) + 1;  /* index of _LOADED table */
    lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
    lua_getfield(L, loaded, modname);  /* get _LOADED[modname] */
    if (!lua_istable(L, -1)) {  /* not found? */
      lua_pop(L, 1);  /* remove previous result */
      /* try global variable (and create one if it does not exist) */
      if (luaL_findtable(L, LUA_GLOBALSINDEX, modname, 1) != NULL)
        lj_err_callerv(L, LJ_ERR_BADMODN, modname);
      lua_pushvalue(L, -1);
      lua_setfield(L, loaded, modname);  /* _LOADED[modname] = new table */
    }
    /* check whether table already has a _NAME field */
    lua_getfield(L, -1, "_NAME");
    if (!lua_isnil(L, -1)) {  /* is table an initialized module? */
      lua_pop(L, 1);
    } else {  /* no; initialize it */
      lua_pop(L, 1);
      modinit(L, modname);
    }
    lua_pushvalue(L, -1);
    setfenv(L);
    dooptions(L, loaded - 1);
    return 0;
  }
  
  static int lj_cf_package_seeall(lua_State *L)
  {
    luaL_checktype(L, 1, LUA_TTABLE);
    if (!lua_getmetatable(L, 1)) {
      lua_createtable(L, 0, 1); /* create new metatable */
      lua_pushvalue(L, -1);
      lua_setmetatable(L, 1);
    }
    lua_pushvalue(L, LUA_GLOBALSINDEX);
    lua_setfield(L, -2, "__index");  /* mt.__index = _G */
    return 0;
  }
  
  /* ------------------------------------------------------------------------ */
  
  #define AUXMARK		"\1"
  
  static void setpath(lua_State *L, const char *fieldname, const char *envname,
  		    const char *def, int noenv)
  {
  #if LJ_TARGET_CONSOLE
    const char *path = NULL;
    UNUSED(envname);
  #else
    const char *path = getenv(envname);
  #endif
    if (path == NULL || noenv) {
      lua_pushstring(L, def);
    } else {
      path = luaL_gsub(L, path, LUA_PATHSEP LUA_PATHSEP,
  			      LUA_PATHSEP AUXMARK LUA_PATHSEP);
      luaL_gsub(L, path, AUXMARK, def);
      lua_remove(L, -2);
    }
    setprogdir(L);
    lua_setfield(L, -2, fieldname);
  }
  
  static const luaL_Reg package_lib[] = {
    { "loadlib",	lj_cf_package_loadlib },
    { "searchpath",  lj_cf_package_searchpath },
    { "seeall",	lj_cf_package_seeall },
    { NULL, NULL }
  };
  
  static const luaL_Reg package_global[] = {
    { "module",	lj_cf_package_module },
    { "require",	lj_cf_package_require },
    { NULL, NULL }
  };
  
  static const lua_CFunction package_loaders[] =
  {
    lj_cf_package_loader_preload,
    lj_cf_package_loader_lua,
    lj_cf_package_loader_c,
    lj_cf_package_loader_croot,
    NULL
  };
  
  LUALIB_API int luaopen_package(lua_State *L)
  {
    int i;
    int noenv;
    luaL_newmetatable(L, "_LOADLIB");
    lj_lib_pushcf(L, lj_cf_package_unloadlib, 1);
    lua_setfield(L, -2, "__gc");
    luaL_register(L, LUA_LOADLIBNAME, package_lib);
    lua_pushvalue(L, -1);
    lua_replace(L, LUA_ENVIRONINDEX);
    lua_createtable(L, sizeof(package_loaders)/sizeof(package_loaders[0])-1, 0);
    for (i = 0; package_loaders[i] != NULL; i++) {
      lj_lib_pushcf(L, package_loaders[i], 1);
      lua_rawseti(L, -2, i+1);
    }
  #if LJ_52
    lua_pushvalue(L, -1);
    lua_setfield(L, -3, "searchers");
  #endif
    lua_setfield(L, -2, "loaders");
    lua_getfield(L, LUA_REGISTRYINDEX, "LUA_NOENV");
    noenv = lua_toboolean(L, -1);
    lua_pop(L, 1);
    setpath(L, "path", LUA_PATH, LUA_PATH_DEFAULT, noenv);
    setpath(L, "cpath", LUA_CPATH, LUA_CPATH_DEFAULT, noenv);
    lua_pushliteral(L, LUA_PATH_CONFIG);
    lua_setfield(L, -2, "config");
    luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 16);
    lua_setfield(L, -2, "loaded");
    luaL_findtable(L, LUA_REGISTRYINDEX, "_PRELOAD", 4);
    lua_setfield(L, -2, "preload");
    lua_pushvalue(L, LUA_GLOBALSINDEX);
    luaL_register(L, NULL, package_global);
    lua_pop(L, 1);
    return 1;
  }
  
  