src/liolib.c

   1 /*
   2 ** $Id: liolib.c,v 2.73 2006/05/08 20:14:16 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 topfile(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 = topfile(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 ** this function has a separated environment, which defines the
  97 ** correct __close for 'popen' files
  98 */
  99 static int io_pclose (lua_State *L) {
 100   FILE **p = topfile(L);
 101   int ok = lua_pclose(L, *p);
 102   *p = NULL;
 103   return pushresult(L, ok, NULL);
 104 }
 105
 106
 107 static int io_fclose (lua_State *L) {
 108   FILE **p = topfile(L);
 109   int ok = (fclose(*p) == 0);
 110   *p = NULL;
 111   return pushresult(L, ok, NULL);
 112 }
 113
 114
 115 static int aux_close (lua_State *L) {
 116   lua_getfenv(L, 1);
 117   lua_getfield(L, -1, "__close");
 118   return (lua_tocfunction(L, -1))(L);
 119 }
 120
 121
 122 static int io_close (lua_State *L) {
 123   if (lua_isnone(L, 1))
 124     lua_rawgeti(L, LUA_ENVIRONINDEX, IO_OUTPUT);
 125   tofile(L);  /* make sure argument is a file */
 126   return aux_close(L);
 127 }
 128
 129
 130 static int io_gc (lua_State *L) {
 131   FILE *f = *topfile(L);
 132   /* ignore closed files and standard files */
 133   if (f != NULL && f != stdin && f != stdout && f != stderr)
 134     aux_close(L);
 135   return 0;
 136 }
 137
 138
 139 static int io_tostring (lua_State *L) {
 140   FILE *f = *topfile(L);
 141   if (f == NULL)
 142     lua_pushstring(L, "file (closed)");
 143   else
 144     lua_pushfstring(L, "file (%p)", f);
 145   return 1;
 146 }
 147
 148
 149 static int io_open (lua_State *L) {
 150   const char *filename = luaL_checkstring(L, 1);
 151   const char *mode = luaL_optstring(L, 2, "r");
 152   FILE **pf = newfile(L);
 153   *pf = fopen(filename, mode);
 154   return (*pf == NULL) ? pushresult(L, 0, filename) : 1;
 155 }
 156
 157
 158 static int io_popen (lua_State *L) {
 159   const char *filename = luaL_checkstring(L, 1);
 160   const char *mode = luaL_optstring(L, 2, "r");
 161   FILE **pf = newfile(L);
 162   *pf = lua_popen(L, filename, mode);
 163   return (*pf == NULL) ? pushresult(L, 0, filename) : 1;
 164 }
 165
 166
 167 static int io_tmpfile (lua_State *L) {
 168   FILE **pf = newfile(L);
 169   *pf = tmpfile();
 170   return (*pf == NULL) ? pushresult(L, 0, NULL) : 1;
 171 }
 172
 173
 174 static FILE *getiofile (lua_State *L, int findex) {
 175   FILE *f;
 176   lua_rawgeti(L, LUA_ENVIRONINDEX, findex);
 177   f = *(FILE **)lua_touserdata(L, -1);
 178   if (f == NULL)
 179     luaL_error(L, "standard %s file is closed", fnames[findex - 1]);
 180   return f;
 181 }
 182
 183
 184 static int g_iofile (lua_State *L, int f, const char *mode) {
 185   if (!lua_isnoneornil(L, 1)) {
 186     const char *filename = lua_tostring(L, 1);
 187     if (filename) {
 188       FILE **pf = newfile(L);
 189       *pf = fopen(filename, mode);
 190       if (*pf == NULL)
 191         fileerror(L, 1, filename);
 192     }
 193     else {
 194       tofile(L);  /* check that it's a valid file handle */
 195       lua_pushvalue(L, 1);
 196     }
 197     lua_rawseti(L, LUA_ENVIRONINDEX, f);
 198   }
 199   /* return current value */
 200   lua_rawgeti(L, LUA_ENVIRONINDEX, f);
 201   return 1;
 202 }
 203
 204
 205 static int io_input (lua_State *L) {
 206   return g_iofile(L, IO_INPUT, "r");
 207 }
 208
 209
 210 static int io_output (lua_State *L) {
 211   return g_iofile(L, IO_OUTPUT, "w");
 212 }
 213
 214
 215 static int io_readline (lua_State *L);
 216
 217
 218 static void aux_lines (lua_State *L, int idx, int toclose) {
 219   lua_pushvalue(L, idx);
 220   lua_pushboolean(L, toclose);  /* close/not close file when finished */
 221   lua_pushcclosure(L, io_readline, 2);
 222 }
 223
 224
 225 static int f_lines (lua_State *L) {
 226   tofile(L);  /* check that it's a valid file handle */
 227   aux_lines(L, 1, 0);
 228   return 1;
 229 }
 230
 231
 232 static int io_lines (lua_State *L) {
 233   if (lua_isnoneornil(L, 1)) {  /* no arguments? */
 234     /* will iterate over default input */
 235     lua_rawgeti(L, LUA_ENVIRONINDEX, IO_INPUT);
 236     return f_lines(L);
 237   }
 238   else {
 239     const char *filename = luaL_checkstring(L, 1);
 240     FILE **pf = newfile(L);
 241     *pf = fopen(filename, "r");
 242     if (*pf == NULL)
 243       fileerror(L, 1, filename);
 244     aux_lines(L, lua_gettop(L), 1);
 245     return 1;
 246   }
 247 }
 248
 249
 250 /*
 251 ** {======================================================
 252 ** READ
 253 ** =======================================================
 254 */
 255
 256
 257 static int read_number (lua_State *L, FILE *f) {
 258   lua_Number d;
 259   if (fscanf(f, LUA_NUMBER_SCAN, &d) == 1) {
 260     lua_pushnumber(L, d);
 261     return 1;
 262   }
 263   else return 0;  /* read fails */
 264 }
 265
 266
 267 static int test_eof (lua_State *L, FILE *f) {
 268   int c = getc(f);
 269   ungetc(c, f);
 270   lua_pushlstring(L, NULL, 0);
 271   return (c != EOF);
 272 }
 273
 274
 275 static int read_line (lua_State *L, FILE *f) {
 276   luaL_Buffer b;
 277   luaL_buffinit(L, &b);
 278   for (;;) {
 279     size_t l;
 280     char *p = luaL_prepbuffer(&b);
 281     if (fgets(p, LUAL_BUFFERSIZE, f) == NULL) {  /* eof? */
 282       luaL_pushresult(&b);  /* close buffer */
 283       return (lua_strlen(L, -1) > 0);  /* check whether read something */
 284     }
 285     l = strlen(p);
 286     if (l == 0 || p[l-1] != '\n')
 287       luaL_addsize(&b, l);
 288     else {
 289       luaL_addsize(&b, l - 1);  /* do not include `eol' */
 290       luaL_pushresult(&b);  /* close buffer */
 291       return 1;  /* read at least an `eol' */
 292     }
 293   }
 294 }
 295
 296
 297 static int read_chars (lua_State *L, FILE *f, size_t n) {
 298   size_t rlen;  /* how much to read */
 299   size_t nr;  /* number of chars actually read */
 300   luaL_Buffer b;
 301   luaL_buffinit(L, &b);
 302   rlen = LUAL_BUFFERSIZE;  /* try to read that much each time */
 303   do {
 304     char *p = luaL_prepbuffer(&b);
 305     if (rlen > n) rlen = n;  /* cannot read more than asked */
 306     nr = fread(p, sizeof(char), rlen, f);
 307     luaL_addsize(&b, nr);
 308     n -= nr;  /* still have to read `n' chars */
 309   } while (n > 0 && nr == rlen);  /* until end of count or eof */
 310   luaL_pushresult(&b);  /* close buffer */
 311   return (n == 0 || lua_strlen(L, -1) > 0);
 312 }
 313
 314
 315 static int g_read (lua_State *L, FILE *f, int first) {
 316   int nargs = lua_gettop(L) - 1;
 317   int success;
 318   int n;
 319   clearerr(f);
 320   if (nargs == 0) {  /* no arguments? */
 321     success = read_line(L, f);
 322     n = first+1;  /* to return 1 result */
 323   }
 324   else {  /* ensure stack space for all results and for auxlib's buffer */
 325     luaL_checkstack(L, nargs+LUA_MINSTACK, "too many arguments");
 326     success = 1;
 327     for (n = first; nargs-- && success; n++) {
 328       if (lua_type(L, n) == LUA_TNUMBER) {
 329         size_t l = (size_t)lua_tointeger(L, n);
 330         success = (l == 0) ? test_eof(L, f) : read_chars(L, f, l);
 331       }
 332       else {
 333         const char *p = lua_tostring(L, n);
 334         luaL_argcheck(L, p && p[0] == '*', n, "invalid option");
 335         switch (p[1]) {
 336           case 'n':  /* number */
 337             success = read_number(L, f);
 338             break;
 339           case 'l':  /* line */
 340             success = read_line(L, f);
 341             break;
 342           case 'a':  /* file */
 343             read_chars(L, f, ~((size_t)0));  /* read MAX_SIZE_T chars */
 344             success = 1; /* always success */
 345             break;
 346           default:
 347             return luaL_argerror(L, n, "invalid format");
 348         }
 349       }
 350     }
 351   }
 352   if (ferror(f))
 353     return pushresult(L, 0, NULL);
 354   if (!success) {
 355     lua_pop(L, 1);  /* remove last result */
 356     lua_pushnil(L);  /* push nil instead */
 357   }
 358   return n - first;
 359 }
 360
 361
 362 static int io_read (lua_State *L) {
 363   return g_read(L, getiofile(L, IO_INPUT), 1);
 364 }
 365
 366
 367 static int f_read (lua_State *L) {
 368   return g_read(L, tofile(L), 2);
 369 }
 370
 371
 372 static int io_readline (lua_State *L) {
 373   FILE *f = *(FILE **)lua_touserdata(L, lua_upvalueindex(1));
 374   int sucess;
 375   if (f == NULL)  /* file is already closed? */
 376     luaL_error(L, "file is already closed");
 377   sucess = read_line(L, f);
 378   if (ferror(f))
 379     return luaL_error(L, "%s", strerror(errno));
 380   if (sucess) return 1;
 381   else {  /* EOF */
 382     if (lua_toboolean(L, lua_upvalueindex(2))) {  /* generator created file? */
 383       lua_settop(L, 0);
 384       lua_pushvalue(L, lua_upvalueindex(1));
 385       aux_close(L);  /* close it */
 386     }
 387     return 0;
 388   }
 389 }
 390
 391 /* }====================================================== */
 392
 393
 394 static int g_write (lua_State *L, FILE *f, int arg) {
 395   int nargs = lua_gettop(L) - 1;
 396   int status = 1;
 397   for (; nargs--; arg++) {
 398     if (lua_type(L, arg) == LUA_TNUMBER) {
 399       /* optimization: could be done exactly as for strings */
 400       status = status &&
 401           fprintf(f, LUA_NUMBER_FMT, lua_tonumber(L, arg)) > 0;
 402     }
 403     else {
 404       size_t l;
 405       const char *s = luaL_checklstring(L, arg, &l);
 406       status = status && (fwrite(s, sizeof(char), l, f) == l);
 407     }
 408   }
 409   return pushresult(L, status, NULL);
 410 }
 411
 412
 413 static int io_write (lua_State *L) {
 414   return g_write(L, getiofile(L, IO_OUTPUT), 1);
 415 }
 416
 417
 418 static int f_write (lua_State *L) {
 419   return g_write(L, tofile(L), 2);
 420 }
 421
 422
 423 static int f_seek (lua_State *L) {
 424   static const int mode[] = {SEEK_SET, SEEK_CUR, SEEK_END};
 425   static const char *const modenames[] = {"set", "cur", "end", NULL};
 426   FILE *f = tofile(L);
 427   int op = luaL_checkoption(L, 2, "cur", modenames);
 428   long offset = luaL_optlong(L, 3, 0);
 429   op = fseek(f, offset, mode[op]);
 430   if (op)
 431     return pushresult(L, 0, NULL);  /* error */
 432   else {
 433     lua_pushinteger(L, ftell(f));
 434     return 1;
 435   }
 436 }
 437
 438
 439 static int f_setvbuf (lua_State *L) {
 440   static const int mode[] = {_IONBF, _IOFBF, _IOLBF};
 441   static const char *const modenames[] = {"no", "full", "line", NULL};
 442   FILE *f = tofile(L);
 443   int op = luaL_checkoption(L, 2, NULL, modenames);
 444   lua_Integer sz = luaL_optinteger(L, 3, LUAL_BUFFERSIZE);
 445   int res = setvbuf(f, NULL, mode[op], sz);
 446   return pushresult(L, res == 0, NULL);
 447 }
 448
 449
 450
 451 static int io_flush (lua_State *L) {
 452   return pushresult(L, fflush(getiofile(L, IO_OUTPUT)) == 0, NULL);
 453 }
 454
 455
 456 static int f_flush (lua_State *L) {
 457   return pushresult(L, fflush(tofile(L)) == 0, NULL);
 458 }
 459
 460
 461 static const luaL_Reg iolib[] = {
 462   {"close", io_close},
 463   {"flush", io_flush},
 464   {"input", io_input},
 465   {"lines", io_lines},
 466   {"open", io_open},
 467   {"output", io_output},
 468   {"popen", io_popen},
 469   {"read", io_read},
 470   {"tmpfile", io_tmpfile},
 471   {"type", io_type},
 472   {"write", io_write},
 473   {NULL, NULL}
 474 };
 475
 476
 477 static const luaL_Reg flib[] = {
 478   {"close", io_close},
 479   {"flush", f_flush},
 480   {"lines", f_lines},
 481   {"read", f_read},
 482   {"seek", f_seek},
 483   {"setvbuf", f_setvbuf},
 484   {"write", f_write},
 485   {"__gc", io_gc},
 486   {"__tostring", io_tostring},
 487   {NULL, NULL}
 488 };
 489
 490
 491 static void createmeta (lua_State *L) {
 492   luaL_newmetatable(L, LUA_FILEHANDLE);  /* create metatable for file handles */
 493   lua_pushvalue(L, -1);  /* push metatable */
 494   lua_setfield(L, -2, "__index");  /* metatable.__index = metatable */
 495   luaL_register(L, NULL, flib);  /* file methods */
 496 }
 497
 498
 499 static void createstdfile (lua_State *L, FILE *f, int k, const char *fname) {
 500   *newfile(L) = f;
 501   if (k > 0) {
 502     lua_pushvalue(L, -1);
 503     lua_rawseti(L, LUA_ENVIRONINDEX, k);
 504   }
 505   lua_setfield(L, -2, fname);
 506 }
 507
 508
 509 LUALIB_API int luaopen_io (lua_State *L) {
 510   createmeta(L);
 511   /* create (private) environment (with fields IO_INPUT, IO_OUTPUT, __close) */
 512   lua_createtable(L, 2, 1);
 513   lua_replace(L, LUA_ENVIRONINDEX);
 514   /* open library */
 515   luaL_register(L, LUA_IOLIBNAME, iolib);
 516   /* create (and set) default files */
 517   createstdfile(L, stdin, IO_INPUT, "stdin");
 518   createstdfile(L, stdout, IO_OUTPUT, "stdout");
 519   createstdfile(L, stderr, 0, "stderr");
 520   /* create environment for 'popen' */
 521   lua_getfield(L, -1, "popen");
 522   lua_createtable(L, 0, 1);
 523   lua_pushcfunction(L, io_pclose);
 524   lua_setfield(L, -2, "__close");
 525   lua_setfenv(L, -2);
 526   lua_pop(L, 1);  /* pop 'popen' */
 527   /* set default close function */
 528   lua_pushcfunction(L, io_fclose);
 529   lua_setfield(L, LUA_ENVIRONINDEX, "__close");
 530   return 1;
 531 }
 532