liolib.c

   1 /*
   2 ** $Id: liolib.c,v 2.73.1.3 2008/01/18 17:47:43 roberto Exp $
   3 ** Standard I/O (and system) library
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7
   8 #include <errno.h>
   9 #include <stdio.h>
  10 #include <stdlib.h>
  11 #include <string.h>
  12
  13 #define liolib_c
  14 #define LUA_LIB
  15
  16 #include "lua.h"
  17
  18 #include "lauxlib.h"
  19 #include "lualib.h"
  20
  21
  22
  23 #define IO_INPUT        1
  24 #define IO_OUTPUT       2
  25
  26
  27 static const char *const fnames[] = {"input", "output"};
  28
  29
  30 static int pushresult (lua_State *L, int i, const char *filename) {
  31   int en = errno;  /* calls to Lua API may change this value */
  32   if (i) {
  33     lua_pushboolean(L, 1);
  34     return 1;
  35   }
  36   else {
  37     lua_pushnil(L);
  38     if (filename)
  39       lua_pushfstring(L, "%s: %s", filename, strerror(en));
  40     else
  41       lua_pushfstring(L, "%s", strerror(en));
  42     lua_pushinteger(L, en);
  43     return 3;
  44   }
  45 }
  46
  47
  48 static void fileerror (lua_State *L, int arg, const char *filename) {
  49   lua_pushfstring(L, "%s: %s", filename, strerror(errno));
  50   luaL_argerror(L, arg, lua_tostring(L, -1));
  51 }
  52
  53
  54 #define tofilep(L)      ((FILE **)luaL_checkudata(L, 1, LUA_FILEHANDLE))
  55
  56
  57 static int io_type (lua_State *L) {
  58   void *ud;
  59   luaL_checkany(L, 1);
  60   ud = lua_touserdata(L, 1);
  61   lua_getfield(L, LUA_REGISTRYINDEX, LUA_FILEHANDLE);
  62   if (ud == NULL || !lua_getmetatable(L, 1) || !lua_rawequal(L, -2, -1))
  63     lua_pushnil(L);  /* not a file */
  64   else if (*((FILE **)ud) == NULL)
  65     lua_pushliteral(L, "closed file");
  66   else
  67     lua_pushliteral(L, "file");
  68   return 1;
  69 }
  70
  71
  72 static FILE *tofile (lua_State *L) {
  73   FILE **f = tofilep(L);
  74   if (*f == NULL)
  75     luaL_error(L, "attempt to use a closed file");
  76   return *f;
  77 }
  78
  79
  80
  81 /*
  82 ** When creating file handles, always creates a `closed' file handle
  83 ** before opening the actual file; so, if there is a memory error, the
  84 ** file is not left opened.
  85 */
  86 static FILE **newfile (lua_State *L) {
  87   FILE **pf = (FILE **)lua_newuserdata(L, sizeof(FILE *));
  88   *pf = NULL;  /* file handle is currently `closed' */
  89   luaL_getmetatable(L, LUA_FILEHANDLE);
  90   lua_setmetatable(L, -2);
  91   return pf;
  92 }
  93
  94
  95 /*
  96 ** function to (not) close the standard files stdin, stdout, and stderr
  97 */
  98 static int io_noclose (lua_State *L) {
  99   lua_pushnil(L);
 100   lua_pushliteral(L, "cannot close standard file");
 101   return 2;
 102 }
 103
 104
 105 /*
 106 ** function to close 'popen' files
 107 */
 108 static int io_pclose (lua_State *L) {
 109   FILE **p = tofilep(L);
 110   int ok = lua_pclose(L, *p);
 111   *p = NULL;
 112   return pushresult(L, ok, NULL);
 113 }
 114
 115
 116 /*
 117 ** function to close regular files
 118 */
 119 static int io_fclose (lua_State *L) {
 120   FILE **p = tofilep(L);
 121   int ok = (fclose(*p) == 0);
 122   *p = NULL;
 123   return pushresult(L, ok, NULL);
 124 }
 125
 126
 127 static int aux_close (lua_State *L) {
 128   lua_getfenv(L, 1);
 129   lua_getfield(L, -1, "__close");
 130   return (lua_tocfunction(L, -1))(L);
 131 }
 132
 133
 134 static int io_close (lua_State *L) {
 135   if (lua_isnone(L, 1))
 136     lua_rawgeti(L, LUA_ENVIRONINDEX, IO_OUTPUT);
 137   tofile(L);  /* make sure argument is a file */
 138   return aux_close(L);
 139 }
 140
 141
 142 static int io_gc (lua_State *L) {
 143   FILE *f = *tofilep(L);
 144   /* ignore closed files */
 145   if (f != NULL)
 146     aux_close(L);
 147   return 0;
 148 }
 149
 150
 151 static int io_tostring (lua_State *L) {
 152   FILE *f = *tofilep(L);
 153   if (f == NULL)
 154     lua_pushliteral(L, "file (closed)");
 155   else
 156     lua_pushfstring(L, "file (%p)", f);
 157   return 1;
 158 }
 159
 160
 161 static int io_open (lua_State *L) {
 162   const char *filename = luaL_checkstring(L, 1);
 163   const char *mode = luaL_optstring(L, 2, "r");
 164   FILE **pf = newfile(L);
 165   *pf = fopen(filename, mode);
 166   return (*pf == NULL) ? pushresult(L, 0, filename) : 1;
 167 }
 168
 169
 170 /*
 171 ** this function has a separated environment, which defines the
 172 ** correct __close for 'popen' files
 173 */
 174 static int io_popen (lua_State *L) {
 175   const char *filename = luaL_checkstring(L, 1);
 176   const char *mode = luaL_optstring(L, 2, "r");
 177   FILE **pf = newfile(L);
 178   *pf = lua_popen(L, filename, mode);
 179   return (*pf == NULL) ? pushresult(L, 0, filename) : 1;
 180 }
 181
 182
 183 static int io_tmpfile (lua_State *L) {
 184   FILE **pf = newfile(L);
 185   *pf = tmpfile();
 186   return (*pf == NULL) ? pushresult(L, 0, NULL) : 1;
 187 }
 188
 189
 190 static FILE *getiofile (lua_State *L, int findex) {
 191   FILE *f;
 192   lua_rawgeti(L, LUA_ENVIRONINDEX, findex);
 193   f = *(FILE **)lua_touserdata(L, -1);
 194   if (f == NULL)
 195     luaL_error(L, "standard %s file is closed", fnames[findex - 1]);
 196   return f;
 197 }
 198
 199
 200 static int g_iofile (lua_State *L, int f, const char *mode) {
 201   if (!lua_isnoneornil(L, 1)) {
 202     const char *filename = lua_tostring(L, 1);
 203     if (filename) {
 204       FILE **pf = newfile(L);
 205       *pf = fopen(filename, mode);
 206       if (*pf == NULL)
 207         fileerror(L, 1, filename);
 208     }
 209     else {
 210       tofile(L);  /* check that it's a valid file handle */
 211       lua_pushvalue(L, 1);
 212     }
 213     lua_rawseti(L, LUA_ENVIRONINDEX, f);
 214   }
 215   /* return current value */
 216   lua_rawgeti(L, LUA_ENVIRONINDEX, f);
 217   return 1;
 218 }
 219
 220
 221 static int io_input (lua_State *L) {
 222   return g_iofile(L, IO_INPUT, "r");
 223 }
 224
 225
 226 static int io_output (lua_State *L) {
 227   return g_iofile(L, IO_OUTPUT, "w");
 228 }
 229
 230
 231 static int io_readline (lua_State *L);
 232
 233
 234 static void aux_lines (lua_State *L, int idx, int toclose) {
 235   lua_pushvalue(L, idx);
 236   lua_pushboolean(L, toclose);  /* close/not close file when finished */
 237   lua_pushcclosure(L, io_readline, 2);
 238 }
 239
 240
 241 static int f_lines (lua_State *L) {
 242   tofile(L);  /* check that it's a valid file handle */
 243   aux_lines(L, 1, 0);
 244   return 1;
 245 }
 246
 247
 248 static int io_lines (lua_State *L) {
 249   if (lua_isnoneornil(L, 1)) {  /* no arguments? */
 250     /* will iterate over default input */
 251     lua_rawgeti(L, LUA_ENVIRONINDEX, IO_INPUT);
 252     return f_lines(L);
 253   }
 254   else {
 255     const char *filename = luaL_checkstring(L, 1);
 256     FILE **pf = newfile(L);
 257     *pf = fopen(filename, "r");
 258     if (*pf == NULL)
 259       fileerror(L, 1, filename);
 260     aux_lines(L, lua_gettop(L), 1);
 261     return 1;
 262   }
 263 }
 264
 265
 266 /*
 267 ** {======================================================
 268 ** READ
 269 ** =======================================================
 270 */
 271
 272
 273 static int read_number (lua_State *L, FILE *f) {
 274   lua_Number d;
 275   if (fscanf(f, LUA_NUMBER_SCAN, &d) == 1) {
 276     lua_pushnumber(L, d);
 277     return 1;
 278   }
 279   else return 0;  /* read fails */
 280 }
 281
 282
 283 static int test_eof (lua_State *L, FILE *f) {
 284   int c = getc(f);
 285   ungetc(c, f);
 286   lua_pushlstring(L, NULL, 0);
 287   return (c != EOF);
 288 }
 289
 290
 291 static int read_line (lua_State *L, FILE *f) {
 292   luaL_Buffer b;
 293   luaL_buffinit(L, &b);
 294   for (;;) {
 295     size_t l;
 296     char *p = luaL_prepbuffer(&b);
 297     if (fgets(p, LUAL_BUFFERSIZE, f) == NULL) {  /* eof? */
 298       luaL_pushresult(&b);  /* close buffer */
 299       return (lua_objlen(L, -1) > 0);  /* check whether read something */
 300     }
 301     l = strlen(p);
 302     if (l == 0 || p[l-1] != '\n')
 303       luaL_addsize(&b, l);
 304     else {
 305       luaL_addsize(&b, l - 1);  /* do not include `eol' */
 306       luaL_pushresult(&b);  /* close buffer */
 307       return 1;  /* read at least an `eol' */
 308     }
 309   }
 310 }
 311
 312
 313 static int read_chars (lua_State *L, FILE *f, size_t n) {
 314   size_t rlen;  /* how much to read */
 315   size_t nr;  /* number of chars actually read */
 316   luaL_Buffer b;
 317   luaL_buffinit(L, &b);
 318   rlen = LUAL_BUFFERSIZE;  /* try to read that much each time */
 319   do {
 320     char *p = luaL_prepbuffer(&b);
 321     if (rlen > n) rlen = n;  /* cannot read more than asked */
 322     nr = fread(p, sizeof(char), rlen, f);
 323     luaL_addsize(&b, nr);
 324     n -= nr;  /* still have to read `n' chars */
 325   } while (n > 0 && nr == rlen);  /* until end of count or eof */
 326   luaL_pushresult(&b);  /* close buffer */
 327   return (n == 0 || lua_objlen(L, -1) > 0);
 328 }
 329
 330
 331 static int g_read (lua_State *L, FILE *f, int first) {
 332   int nargs = lua_gettop(L) - 1;
 333   int success;
 334   int n;
 335   clearerr(f);
 336   if (nargs == 0) {  /* no arguments? */
 337     success = read_line(L, f);
 338     n = first+1;  /* to return 1 result */
 339   }
 340   else {  /* ensure stack space for all results and for auxlib's buffer */
 341     luaL_checkstack(L, nargs+LUA_MINSTACK, "too many arguments");
 342     success = 1;
 343     for (n = first; nargs-- && success; n++) {
 344       if (lua_type(L, n) == LUA_TNUMBER) {
 345         size_t l = (size_t)lua_tointeger(L, n);
 346         success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l);
 347       }
 348       else {
 349         const char *p = lua_tostring(L, n);
 350         luaL_argcheck(L, p && p[0] == '*', n, "invalid option");
 351         switch (p[1]) {
 352           case 'n':  /* number */
 353             success = read_number(L, f);
 354             break;
 355           case 'l':  /* line */
 356             success = read_line(L, f);
 357             break;
 358           case 'a':  /* file */
 359             read_chars(L, f, ~((size_t)0));  /* read MAX_SIZE_T chars */
 360             success = 1; /* always success */
 361             break;
 362           default:
 363             return luaL_argerror(L, n, "invalid format");
 364         }
 365       }
 366     }
 367   }
 368   if (ferror(f))
 369     return pushresult(L, 0, NULL);
 370   if (!success) {
 371     lua_pop(L, 1);  /* remove last result */
 372     lua_pushnil(L);  /* push nil instead */
 373   }
 374   return n - first;
 375 }
 376
 377
 378 static int io_read (lua_State *L) {
 379   return g_read(L, getiofile(L, IO_INPUT), 1);
 380 }
 381
 382
 383 static int f_read (lua_State *L) {
 384   return g_read(L, tofile(L), 2);
 385 }
 386
 387
 388 static int io_readline (lua_State *L) {
 389   FILE *f = *(FILE **)lua_touserdata(L, lua_upvalueindex(1));
 390   int sucess;
 391   if (f == NULL)  /* file is already closed? */
 392     luaL_error(L, "file is already closed");
 393   sucess = read_line(L, f);
 394   if (ferror(f))
 395     return luaL_error(L, "%s", strerror(errno));
 396   if (sucess) return 1;
 397   else {  /* EOF */
 398     if (lua_toboolean(L, lua_upvalueindex(2))) {  /* generator created file? */
 399       lua_settop(L, 0);
 400       lua_pushvalue(L, lua_upvalueindex(1));
 401       aux_close(L);  /* close it */
 402     }
 403     return 0;
 404   }
 405 }
 406
 407 /* }====================================================== */
 408
 409
 410 static int g_write (lua_State *L, FILE *f, int arg) {
 411   int nargs = lua_gettop(L) - 1;
 412   int status = 1;
 413   for (; nargs--; arg++) {
 414     if (lua_type(L, arg) == LUA_TNUMBER) {
 415       /* optimization: could be done exactly as for strings */
 416       status = status &&
 417           fprintf(f, LUA_NUMBER_FMT, lua_tonumber(L, arg)) > 0;
 418     }
 419     else {
 420       size_t l;
 421       const char *s = luaL_checklstring(L, arg, &l);
 422       status = status && (fwrite(s, sizeof(char), l, f) == l);
 423     }
 424   }
 425   return pushresult(L, status, NULL);
 426 }
 427
 428
 429 static int io_write (lua_State *L) {
 430   return g_write(L, getiofile(L, IO_OUTPUT), 1);
 431 }
 432
 433
 434 static int f_write (lua_State *L) {
 435   return g_write(L, tofile(L), 2);
 436 }
 437
 438
 439 static int f_seek (lua_State *L) {
 440   static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END};
 441   static const char *const modenames[] = {"set", "cur", "end", NULL};
 442   FILE *f = tofile(L);
 443   int op = luaL_checkoption(L, 2, "cur", modenames);
 444   long offset = luaL_optlong(L, 3, 0);
 445   op = fseek(f, offset, mode[op]);
 446   if (op)
 447     return pushresult(L, 0, NULL);  /* error */
 448   else {
 449     lua_pushinteger(L, ftell(f));
 450     return 1;
 451   }
 452 }
 453
 454
 455 static int f_setvbuf (lua_State *L) {
 456   static const int mode[] = {_IONBF, _IOFBF, _IOLBF};
 457   static const char *const modenames[] = {"no", "full", "line", NULL};
 458   FILE *f = tofile(L);
 459   int op = luaL_checkoption(L, 2, NULL, modenames);
 460   lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE);
 461   int res = setvbuf(f, NULL, mode[op], sz);
 462   return pushresult(L, res == 0, NULL);
 463 }
 464
 465
 466
 467 static int io_flush (lua_State *L) {
 468   return pushresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL);
 469 }
 470
 471
 472 static int f_flush (lua_State *L) {
 473   return pushresult(L, fflush(tofile(L)) == 0, NULL);
 474 }
 475
 476
 477 static const luaL_Reg iolib[] = {
 478   {"close", io_close},
 479   {"flush", io_flush},
 480   {"input", io_input},
 481   {"lines", io_lines},
 482   {"open", io_open},
 483   {"output", io_output},
 484   {"popen", io_popen},
 485   {"read", io_read},
 486   {"tmpfile", io_tmpfile},
 487   {"type", io_type},
 488   {"write", io_write},
 489   {NULL, NULL}
 490 };
 491
 492
 493 static const luaL_Reg flib[] = {
 494   {"close", io_close},
 495   {"flush", f_flush},
 496   {"lines", f_lines},
 497   {"read", f_read},
 498   {"seek", f_seek},
 499   {"setvbuf", f_setvbuf},
 500   {"write", f_write},
 501   {"__gc", io_gc},
 502   {"__tostring", io_tostring},
 503   {NULL, NULL}
 504 };
 505
 506
 507 static void createmeta (lua_State *L) {
 508   luaL_newmetatable(L, LUA_FILEHANDLE);  /* create metatable for file handles */
 509   lua_pushvalue(L, -1);  /* push metatable */
 510   lua_setfield(L, -2, "__index");  /* metatable.__index = metatable */
 511   luaL_register(L, NULL, flib);  /* file methods */
 512 }
 513
 514
 515 static void createstdfile (lua_State *L, FILE *f, int k, const char *fname) {
 516   *newfile(L) = f;
 517   if (k > 0) {
 518     lua_pushvalue(L, -1);
 519     lua_rawseti(L, LUA_ENVIRONINDEX, k);
 520   }
 521   lua_pushvalue(L, -2);  /* copy environment */
 522   lua_setfenv(L, -2);  /* set it */
 523   lua_setfield(L, -3, fname);
 524 }
 525
 526
 527 static void newfenv (lua_State *L, lua_CFunction cls) {
 528   lua_createtable(L, 0, 1);
 529   lua_pushcfunction(L, cls);
 530   lua_setfield(L, -2, "__close");
 531 }
 532
 533
 534 LUALIB_API int luaopen_io (lua_State *L) {
 535   createmeta(L);
 536   /* create (private) environment (with fields IO_INPUT, IO_OUTPUT, __close) */
 537   newfenv(L, io_fclose);
 538   lua_replace(L, LUA_ENVIRONINDEX);
 539   /* open library */
 540   luaL_register(L, LUA_IOLIBNAME, iolib);
 541   /* create (and set) default files */
 542   newfenv(L, io_noclose);  /* close function for default files */
 543   createstdfile(L, stdin, IO_INPUT, "stdin");
 544   createstdfile(L, stdout, IO_OUTPUT, "stdout");
 545   createstdfile(L, stderr, 0, "stderr");
 546   lua_pop(L, 1);  /* pop environment for default files */
 547   lua_getfield(L, -1, "popen");
 548   newfenv(L, io_pclose);  /* create environment for 'popen' */
 549   lua_setfenv(L, -2);  /* set fenv for 'popen' */
 550   lua_pop(L, 1);  /* pop 'popen' */
 551   return 1;
 552 }
 553