apps/plugins/lua/loadlib.c

   1 /*
   2 ** $Id: loadlib.c,v 1.52.1.3 2008/08/06 13:29:28 roberto Exp $
   3 ** Dynamic library loader for Lua
   4 ** See Copyright Notice in lua.h
   5 **
   6 ** This module contains an implementation of loadlib for Unix systems
   7 ** that have dlfcn, an implementation for Darwin (Mac OS X), an
   8 ** implementation for Windows, and a stub for other systems.
   9 */
  10
  11
  12 #include <stdlib.h>
  13 #include <string.h>
  14
  15
  16 #define loadlib_c
  17 #define LUA_LIB
  18
  19 #include "lua.h"
  20
  21 #include "lauxlib.h"
  22 #include "lualib.h"
  23 #include "rocklib.h"
  24
  25
  26 #define setprogdir(L)       ((void)0)
  27
  28
  29 /*
  30 ** {======================================================
  31 ** 'require' function
  32 ** =======================================================
  33 */
  34
  35
  36 static int readable (const char *filename) {
  37   int f = rb->open(filename, O_RDONLY);  /* try to open file */
  38   if (f < 0) return 0;  /* open failed */
  39   rb->close(f);
  40   return 1;
  41 }
  42
  43
  44 static const char *pushnexttemplate (lua_State *L, const char *path) {
  45   const char *l;
  46   while (*path == *LUA_PATHSEP) path++;  /* skip separators */
  47   if (*path == '\0') return NULL;  /* no more templates */
  48   l = strchr(path, *LUA_PATHSEP);  /* find next separator */
  49   if (l == NULL) l = path + strlen(path);
  50   lua_pushlstring(L, path, l - path);  /* template */
  51   return l;
  52 }
  53
  54
  55 static const char *findfile (lua_State *L, const char *name,
  56                                            const char *pname) {
  57   const char *path, *current_path = get_current_path(L, 2);
  58   name = luaL_gsub(L, name, ".", LUA_DIRSEP);
  59   lua_getfield(L, LUA_ENVIRONINDEX, pname);
  60   path = lua_tostring(L, -1);
  61   if (path == NULL)
  62     luaL_error(L, LUA_QL("package.%s") " must be a string", pname);
  63   lua_pushliteral(L, "");  /* error accumulator */
  64   while ((path = pushnexttemplate(L, path)) != NULL) {
  65     const char *filename;
  66     filename = luaL_gsub(L, lua_tostring(L, -1), LUA_PATH_MARK, name);
  67     if(current_path != NULL) filename = luaL_gsub(L, filename, "$", current_path);
  68     lua_remove(L, -2);  /* remove path template */
  69     if (readable(filename))  /* does file exist and is readable? */
  70       return filename;  /* return that file name */
  71     lua_pushfstring(L, "\n\tno file " LUA_QS, filename);
  72     lua_remove(L, -2);  /* remove file name */
  73     lua_concat(L, 2);  /* add entry to possible error message */
  74   }
  75   return NULL;  /* not found */
  76 }
  77
  78
  79 static void loaderror (lua_State *L, const char *filename) {
  80   luaL_error(L, "error loading module " LUA_QS " from file " LUA_QS ":\n\t%s",
  81                 lua_tostring(L, 1), filename, lua_tostring(L, -1));
  82 }
  83
  84
  85 static int loader_Lua (lua_State *L) {
  86   const char *filename;
  87   const char *name = luaL_checkstring(L, 1);
  88   filename = findfile(L, name, "path");
  89   if (filename == NULL) return 1;  /* library not found in this path */
  90   if (luaL_loadfile(L, filename) != 0)
  91     loaderror(L, filename);
  92   return 1;  /* library loaded successfully */
  93 }
  94
  95
  96 static int loader_preload (lua_State *L) {
  97   const char *name = luaL_checkstring(L, 1);
  98   lua_getfield(L, LUA_ENVIRONINDEX, "preload");
  99   if (!lua_istable(L, -1))
 100     luaL_error(L, LUA_QL("package.preload") " must be a table");
 101   lua_getfield(L, -1, name);
 102   if (lua_isnil(L, -1))  /* not found? */
 103     lua_pushfstring(L, "\n\tno field package.preload['%s']", name);
 104   return 1;
 105 }
 106
 107
 108 static const int sentinel_ = 0;
 109 #define sentinel    ((void *)&sentinel_)
 110
 111
 112 static int ll_require (lua_State *L) {
 113   const char *name = luaL_checkstring(L, 1);
 114   int i;
 115   lua_settop(L, 1);  /* _LOADED table will be at index 2 */
 116   lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
 117   lua_getfield(L, 2, name);
 118   if (lua_toboolean(L, -1)) {  /* is it there? */
 119     if (lua_touserdata(L, -1) == sentinel)  /* check loops */
 120       luaL_error(L, "loop or previous error loading module " LUA_QS, name);
 121     return 1;  /* package is already loaded */
 122   }
 123   /* else must load it; iterate over available loaders */
 124   lua_getfield(L, LUA_ENVIRONINDEX, "loaders");
 125   if (!lua_istable(L, -1))
 126     luaL_error(L, LUA_QL("package.loaders") " must be a table");
 127   lua_pushliteral(L, "");  /* error message accumulator */
 128   for (i=1; ; i++) {
 129     lua_rawgeti(L, -2, i);  /* get a loader */
 130     if (lua_isnil(L, -1))
 131       luaL_error(L, "module " LUA_QS " not found:%s",
 132                     name, lua_tostring(L, -2));
 133     lua_pushstring(L, name);
 134     lua_call(L, 1, 1);  /* call it */
 135     if (lua_isfunction(L, -1))  /* did it find module? */
 136       break;  /* module loaded successfully */
 137     else if (lua_isstring(L, -1))  /* loader returned error message? */
 138       lua_concat(L, 2);  /* accumulate it */
 139     else
 140       lua_pop(L, 1);
 141   }
 142   lua_pushlightuserdata(L, sentinel);
 143   lua_setfield(L, 2, name);  /* _LOADED[name] = sentinel */
 144   lua_pushstring(L, name);  /* pass name as argument to module */
 145   lua_call(L, 1, 1);  /* run loaded module */
 146   if (!lua_isnil(L, -1))  /* non-nil return? */
 147     lua_setfield(L, 2, name);  /* _LOADED[name] = returned value */
 148   lua_getfield(L, 2, name);
 149   if (lua_touserdata(L, -1) == sentinel) {   /* module did not set a value? */
 150     lua_pushboolean(L, 1);  /* use true as result */
 151     lua_pushvalue(L, -1);  /* extra copy to be returned */
 152     lua_setfield(L, 2, name);  /* _LOADED[name] = true */
 153   }
 154   return 1;
 155 }
 156
 157 /* }====================================================== */
 158
 159
 160
 161 /*
 162 ** {======================================================
 163 ** 'module' function
 164 ** =======================================================
 165 */
 166
 167
 168 static void setfenv (lua_State *L) {
 169   lua_Debug ar;
 170   if (lua_getstack(L, 1, &ar) == 0 ||
 171       lua_getinfo(L, "f", &ar) == 0 ||  /* get calling function */
 172       lua_iscfunction(L, -1))
 173     luaL_error(L, LUA_QL("module") " not called from a Lua function");
 174   lua_pushvalue(L, -2);
 175   lua_setfenv(L, -2);
 176   lua_pop(L, 1);
 177 }
 178
 179
 180 static void dooptions (lua_State *L, int n) {
 181   int i;
 182   for (i = 2; i <= n; i++) {
 183     lua_pushvalue(L, i);  /* get option (a function) */
 184     lua_pushvalue(L, -2);  /* module */
 185     lua_call(L, 1, 0);
 186   }
 187 }
 188
 189
 190 static void modinit (lua_State *L, const char *modname) {
 191   const char *dot;
 192   lua_pushvalue(L, -1);
 193   lua_setfield(L, -2, "_M");  /* module._M = module */
 194   lua_pushstring(L, modname);
 195   lua_setfield(L, -2, "_NAME");
 196   dot = rb->strrchr(modname, '.');  /* look for last dot in module name */
 197   if (dot == NULL) dot = modname;
 198   else dot++;
 199   /* set _PACKAGE as package name (full module name minus last part) */
 200   lua_pushlstring(L, modname, dot - modname);
 201   lua_setfield(L, -2, "_PACKAGE");
 202 }
 203
 204
 205 static int ll_module (lua_State *L) {
 206   const char *modname = luaL_checkstring(L, 1);
 207   int loaded = lua_gettop(L) + 1;  /* index of _LOADED table */
 208   lua_getfield(L, LUA_REGISTRYINDEX, "_LOADED");
 209   lua_getfield(L, loaded, modname);  /* get _LOADED[modname] */
 210   if (!lua_istable(L, -1)) {  /* not found? */
 211     lua_pop(L, 1);  /* remove previous result */
 212     /* try global variable (and create one if it does not exist) */
 213     if (luaL_findtable(L, LUA_GLOBALSINDEX, modname, 1) != NULL)
 214       return luaL_error(L, "name conflict for module " LUA_QS, modname);
 215     lua_pushvalue(L, -1);
 216     lua_setfield(L, loaded, modname);  /* _LOADED[modname] = new table */
 217   }
 218   /* check whether table already has a _NAME field */
 219   lua_getfield(L, -1, "_NAME");
 220   if (!lua_isnil(L, -1))  /* is table an initialized module? */
 221     lua_pop(L, 1);
 222   else {  /* no; initialize it */
 223     lua_pop(L, 1);
 224     modinit(L, modname);
 225   }
 226   lua_pushvalue(L, -1);
 227   setfenv(L);
 228   dooptions(L, loaded - 1);
 229   return 0;
 230 }
 231
 232
 233 static int ll_seeall (lua_State *L) {
 234   luaL_checktype(L, 1, LUA_TTABLE);
 235   if (!lua_getmetatable(L, 1)) {
 236     lua_createtable(L, 0, 1); /* create new metatable */
 237     lua_pushvalue(L, -1);
 238     lua_setmetatable(L, 1);
 239   }
 240   lua_pushvalue(L, LUA_GLOBALSINDEX);
 241   lua_setfield(L, -2, "__index");  /* mt.__index = _G */
 242   return 0;
 243 }
 244
 245
 246 /* }====================================================== */
 247
 248
 249
 250 /* auxiliary mark (for internal use) */
 251 #define AUXMARK     "\1"
 252
 253 static void setpath (lua_State *L, const char *fieldname, const char *envname,
 254                                    const char *def) {
 255   (void)envname;
 256   lua_pushstring(L, def);  /* use default */
 257   setprogdir(L);
 258   lua_setfield(L, -2, fieldname);
 259 }
 260
 261
 262 static const luaL_Reg pk_funcs[] = {
 263   {"seeall", ll_seeall},
 264   {NULL, NULL}
 265 };
 266
 267
 268 static const luaL_Reg ll_funcs[] = {
 269   {"module", ll_module},
 270   {"require", ll_require},
 271   {NULL, NULL}
 272 };
 273
 274
 275 static const lua_CFunction loaders[] =
 276   {loader_preload, loader_Lua, NULL};
 277
 278
 279 LUALIB_API int luaopen_package (lua_State *L) {
 280   int i;
 281   /* create new type _LOADLIB */
 282   luaL_newmetatable(L, "_LOADLIB");
 283   /* create `package' table */
 284   luaL_register(L, LUA_LOADLIBNAME, pk_funcs);
 285 #if defined(LUA_COMPAT_LOADLIB)
 286   lua_getfield(L, -1, "loadlib");
 287   lua_setfield(L, LUA_GLOBALSINDEX, "loadlib");
 288 #endif
 289   lua_pushvalue(L, -1);
 290   lua_replace(L, LUA_ENVIRONINDEX);
 291   /* create `loaders' table */
 292   lua_createtable(L, 0, sizeof(loaders)/sizeof(loaders[0]) - 1);
 293   /* fill it with pre-defined loaders */
 294   for (i=0; loaders[i] != NULL; i++) {
 295     lua_pushcfunction(L, loaders[i]);
 296     lua_rawseti(L, -2, i+1);
 297   }
 298   lua_setfield(L, -2, "loaders");  /* put it in field `loaders' */
 299   setpath(L, "path", LUA_PATH, LUA_PATH_DEFAULT);  /* set field `path' */
 300   /* store config information */
 301   lua_pushliteral(L, LUA_DIRSEP "\n" LUA_PATHSEP "\n" LUA_PATH_MARK "\n"
 302                      LUA_EXECDIR "\n" LUA_IGMARK);
 303   lua_setfield(L, -2, "config");
 304   /* set field `loaded' */
 305   luaL_findtable(L, LUA_REGISTRYINDEX, "_LOADED", 2);
 306   lua_setfield(L, -2, "loaded");
 307   /* set field `preload' */
 308   lua_newtable(L);
 309   lua_setfield(L, -2, "preload");
 310   lua_pushvalue(L, LUA_GLOBALSINDEX);
 311   luaL_register(L, NULL, ll_funcs);  /* open lib into global table */
 312   lua_pop(L, 1);
 313   return 1;  /* return 'package' table */
 314 }
 315