Modules/_fileio.c

   1 /* Author: Daniel Stutzbach */
   2
   3 #define PY_SSIZE_T_CLEAN
   4 #include "Python.h"
   5 #include <sys/types.h>
   6 #include <sys/stat.h>
   7 #include <fcntl.h>
   8 #include <stddef.h> /* For offsetof */
   9
  10 /*
  11  * Known likely problems:
  12  *
  13  * - Files larger then 2**32-1
  14  * - Files with unicode filenames
  15  * - Passing numbers greater than 2**32-1 when an integer is expected
  16  * - Making it work on Windows and other oddball platforms
  17  *
  18  * To Do:
  19  *
  20  * - autoconfify header file inclusion
  21  */
  22
  23 #ifdef MS_WINDOWS
  24 /* can simulate truncate with Win32 API functions; see file_truncate */
  25 #define HAVE_FTRUNCATE
  26 #define WIN32_LEAN_AND_MEAN
  27 #include <windows.h>
  28 #endif
  29
  30 typedef struct {
  31         PyObject_HEAD
  32         int fd;
  33         unsigned readable : 1;
  34         unsigned writable : 1;
  35         int seekable : 2; /* -1 means unknown */
  36         int closefd : 1;
  37         PyObject *weakreflist;
  38 } PyFileIOObject;
  39
  40 PyTypeObject PyFileIO_Type;
  41
  42 #define PyFileIO_Check(op) (PyObject_TypeCheck((op), &PyFileIO_Type))
  43
  44 /* Returns 0 on success, errno (which is < 0) on failure. */
  45 static int
  46 internal_close(PyFileIOObject *self)
  47 {
  48         int save_errno = 0;
  49         if (self->fd >= 0) {
  50                 int fd = self->fd;
  51                 self->fd = -1;
  52                 Py_BEGIN_ALLOW_THREADS
  53                 if (close(fd) < 0)
  54                         save_errno = errno;
  55                 Py_END_ALLOW_THREADS
  56         }
  57         return save_errno;
  58 }
  59
  60 static PyObject *
  61 fileio_close(PyFileIOObject *self)
  62 {
  63         if (!self->closefd) {
  64                 if (PyErr_WarnEx(PyExc_RuntimeWarning,
  65                                  "Trying to close unclosable fd!", 3) < 0) {
  66                         return NULL;
  67                 }
  68                 Py_RETURN_NONE;
  69         }
  70         errno = internal_close(self);
  71         if (errno < 0) {
  72                 PyErr_SetFromErrno(PyExc_IOError);
  73                 return NULL;
  74         }
  75
  76         Py_RETURN_NONE;
  77 }
  78
  79 static PyObject *
  80 fileio_new(PyTypeObject *type, PyObject *args, PyObject *kews)
  81 {
  82         PyFileIOObject *self;
  83
  84         assert(type != NULL && type->tp_alloc != NULL);
  85
  86         self = (PyFileIOObject *) type->tp_alloc(type, 0);
  87         if (self != NULL) {
  88                 self->fd = -1;
  89                 self->weakreflist = NULL;
  90         }
  91
  92         return (PyObject *) self;
  93 }
  94
  95 /* On Unix, open will succeed for directories.
  96    In Python, there should be no file objects referring to
  97    directories, so we need a check.  */
  98
  99 static int
 100 dircheck(PyFileIOObject* self)
 101 {
 102 #if defined(HAVE_FSTAT) && defined(S_IFDIR) && defined(EISDIR)
 103         struct stat buf;
 104         if (self->fd < 0)
 105                 return 0;
 106         if (fstat(self->fd, &buf) == 0 && S_ISDIR(buf.st_mode)) {
 107                 char *msg = strerror(EISDIR);
 108                 PyObject *exc;
 109                 internal_close(self);
 110
 111                 exc = PyObject_CallFunction(PyExc_IOError, "(is)",
 112                                             EISDIR, msg);
 113                 PyErr_SetObject(PyExc_IOError, exc);
 114                 Py_XDECREF(exc);
 115                 return -1;
 116         }
 117 #endif
 118         return 0;
 119 }
 120
 121
 122 static int
 123 fileio_init(PyObject *oself, PyObject *args, PyObject *kwds)
 124 {
 125         PyFileIOObject *self = (PyFileIOObject *) oself;
 126         static char *kwlist[] = {"file", "mode", "closefd", NULL};
 127         char *name = NULL;
 128         char *mode = "r";
 129         char *s;
 130 #ifdef MS_WINDOWS
 131         Py_UNICODE *widename = NULL;
 132 #endif
 133         int ret = 0;
 134         int rwa = 0, plus = 0, append = 0;
 135         int flags = 0;
 136         int fd = -1;
 137         int closefd = 1;
 138
 139         assert(PyFileIO_Check(oself));
 140         if (self->fd >= 0) {
 141                 /* Have to close the existing file first. */
 142                 if (internal_close(self) < 0)
 143                         return -1;
 144         }
 145
 146         if (PyArg_ParseTupleAndKeywords(args, kwds, "i|si:fileio",
 147                                         kwlist, &fd, &mode, &closefd)) {
 148                 if (fd < 0) {
 149                         PyErr_SetString(PyExc_ValueError,
 150                                         "Negative filedescriptor");
 151                         return -1;
 152                 }
 153         }
 154         else {
 155                 PyErr_Clear();
 156
 157 #ifdef Py_WIN_WIDE_FILENAMES
 158             if (GetVersion() < 0x80000000) {
 159                 /* On NT, so wide API available */
 160                 PyObject *po;
 161                 if (PyArg_ParseTupleAndKeywords(args, kwds, "U|si:fileio",
 162                                                 kwlist, &po, &mode, &closefd)
 163                                                 ) {
 164                         widename = PyUnicode_AS_UNICODE(po);
 165                 } else {
 166                         /* Drop the argument parsing error as narrow
 167                            strings are also valid. */
 168                         PyErr_Clear();
 169                 }
 170             }
 171             if (widename == NULL)
 172 #endif
 173             {
 174                 if (!PyArg_ParseTupleAndKeywords(args, kwds, "et|si:fileio",
 175                                                  kwlist,
 176                                                  Py_FileSystemDefaultEncoding,
 177                                                  &name, &mode, &closefd))
 178                         goto error;
 179             }
 180         }
 181
 182         self->readable = self->writable = 0;
 183         self->seekable = -1;
 184         s = mode;
 185         while (*s) {
 186                 switch (*s++) {
 187                 case 'r':
 188                         if (rwa) {
 189                         bad_mode:
 190                                 PyErr_SetString(PyExc_ValueError,
 191                                                 "Must have exactly one of read/write/append mode");
 192                                 goto error;
 193                         }
 194                         rwa = 1;
 195                         self->readable = 1;
 196                         break;
 197                 case 'w':
 198                         if (rwa)
 199                                 goto bad_mode;
 200                         rwa = 1;
 201                         self->writable = 1;
 202                         flags |= O_CREAT | O_TRUNC;
 203                         break;
 204                 case 'a':
 205                         if (rwa)
 206                                 goto bad_mode;
 207                         rwa = 1;
 208                         self->writable = 1;
 209                         flags |= O_CREAT;
 210                         append = 1;
 211                         break;
 212                 case '+':
 213                         if (plus)
 214                                 goto bad_mode;
 215                         self->readable = self->writable = 1;
 216                         plus = 1;
 217                         break;
 218                 default:
 219                         PyErr_Format(PyExc_ValueError,
 220                                      "invalid mode: %.200s", mode);
 221                         goto error;
 222                 }
 223         }
 224
 225         if (!rwa)
 226                 goto bad_mode;
 227
 228         if (self->readable && self->writable)
 229                 flags |= O_RDWR;
 230         else if (self->readable)
 231                 flags |= O_RDONLY;
 232         else
 233                 flags |= O_WRONLY;
 234
 235 #ifdef O_BINARY
 236         flags |= O_BINARY;
 237 #endif
 238
 239 #ifdef O_APPEND
 240         if (append)
 241                 flags |= O_APPEND;
 242 #endif
 243
 244         if (fd >= 0) {
 245                 self->fd = fd;
 246                 self->closefd = closefd;
 247         }
 248         else {
 249                 self->closefd = 1;
 250                 if (!closefd) {
 251                         PyErr_SetString(PyExc_ValueError,
 252                             "Cannot use closefd=True with file name");
 253                         goto error;
 254                 }
 255
 256                 Py_BEGIN_ALLOW_THREADS
 257                 errno = 0;
 258 #ifdef MS_WINDOWS
 259                 if (widename != NULL)
 260                         self->fd = _wopen(widename, flags, 0666);
 261                 else
 262 #endif
 263                         self->fd = open(name, flags, 0666);
 264                 Py_END_ALLOW_THREADS
 265                 if (self->fd < 0 || dircheck(self) < 0) {
 266 #ifdef MS_WINDOWS
 267                         PyErr_SetFromErrnoWithUnicodeFilename(PyExc_IOError, widename);
 268 #else
 269                         PyErr_SetFromErrnoWithFilename(PyExc_IOError, name);
 270 #endif
 271                         goto error;
 272                 }
 273         }
 274
 275         goto done;
 276
 277  error:
 278         ret = -1;
 279
 280  done:
 281         return ret;
 282 }
 283
 284 static void
 285 fileio_dealloc(PyFileIOObject *self)
 286 {
 287         if (self->weakreflist != NULL)
 288                 PyObject_ClearWeakRefs((PyObject *) self);
 289
 290         if (self->fd >= 0 && self->closefd) {
 291                 errno = internal_close(self);
 292                 if (errno < 0) {
 293                         PySys_WriteStderr("close failed: [Errno %d] %s\n",
 294                                           errno, strerror(errno));
 295                 }
 296         }
 297
 298         Py_TYPE(self)->tp_free((PyObject *)self);
 299 }
 300
 301 static PyObject *
 302 err_closed(void)
 303 {
 304         PyErr_SetString(PyExc_ValueError, "I/O operation on closed file");
 305         return NULL;
 306 }
 307
 308 static PyObject *
 309 err_mode(char *action)
 310 {
 311         PyErr_Format(PyExc_ValueError, "File not open for %s", action);
 312         return NULL;
 313 }
 314
 315 static PyObject *
 316 fileio_fileno(PyFileIOObject *self)
 317 {
 318         if (self->fd < 0)
 319                 return err_closed();
 320         return PyInt_FromLong((long) self->fd);
 321 }
 322
 323 static PyObject *
 324 fileio_readable(PyFileIOObject *self)
 325 {
 326         if (self->fd < 0)
 327                 return err_closed();
 328         return PyBool_FromLong((long) self->readable);
 329 }
 330
 331 static PyObject *
 332 fileio_writable(PyFileIOObject *self)
 333 {
 334         if (self->fd < 0)
 335                 return err_closed();
 336         return PyBool_FromLong((long) self->writable);
 337 }
 338
 339 static PyObject *
 340 fileio_seekable(PyFileIOObject *self)
 341 {
 342         if (self->fd < 0)
 343                 return err_closed();
 344         if (self->seekable < 0) {
 345                 int ret;
 346                 Py_BEGIN_ALLOW_THREADS
 347                 ret = lseek(self->fd, 0, SEEK_CUR);
 348                 Py_END_ALLOW_THREADS
 349                 if (ret < 0)
 350                         self->seekable = 0;
 351                 else
 352                         self->seekable = 1;
 353         }
 354         return PyBool_FromLong((long) self->seekable);
 355 }
 356
 357 static PyObject *
 358 fileio_readinto(PyFileIOObject *self, PyObject *args)
 359 {
 360         char *ptr;
 361         Py_ssize_t n;
 362
 363         if (self->fd < 0)
 364                 return err_closed();
 365         if (!self->readable)
 366                 return err_mode("reading");
 367
 368         if (!PyArg_ParseTuple(args, "w#", &ptr, &n))
 369                 return NULL;
 370
 371         Py_BEGIN_ALLOW_THREADS
 372         errno = 0;
 373         n = read(self->fd, ptr, n);
 374         Py_END_ALLOW_THREADS
 375         if (n < 0) {
 376                 if (errno == EAGAIN)
 377                         Py_RETURN_NONE;
 378                 PyErr_SetFromErrno(PyExc_IOError);
 379                 return NULL;
 380         }
 381
 382         return PyLong_FromSsize_t(n);
 383 }
 384
 385 #define DEFAULT_BUFFER_SIZE (8*1024)
 386
 387 static PyObject *
 388 fileio_readall(PyFileIOObject *self)
 389 {
 390         PyObject *result;
 391         Py_ssize_t total = 0;
 392         int n;
 393
 394         result = PyString_FromStringAndSize(NULL, DEFAULT_BUFFER_SIZE);
 395         if (result == NULL)
 396                 return NULL;
 397
 398         while (1) {
 399                 Py_ssize_t newsize = total + DEFAULT_BUFFER_SIZE;
 400                 if (PyString_GET_SIZE(result) < newsize) {
 401                         if (_PyString_Resize(&result, newsize) < 0) {
 402                                 if (total == 0) {
 403                                         Py_DECREF(result);
 404                                         return NULL;
 405                                 }
 406                                 PyErr_Clear();
 407                                 break;
 408                         }
 409                 }
 410                 Py_BEGIN_ALLOW_THREADS
 411                 errno = 0;
 412                 n = read(self->fd,
 413                          PyString_AS_STRING(result) + total,
 414                          newsize - total);
 415                 Py_END_ALLOW_THREADS
 416                 if (n == 0)
 417                         break;
 418                 if (n < 0) {
 419                         if (total > 0)
 420                                 break;
 421                         if (errno == EAGAIN) {
 422                                 Py_DECREF(result);
 423                                 Py_RETURN_NONE;
 424                         }
 425                         Py_DECREF(result);
 426                         PyErr_SetFromErrno(PyExc_IOError);
 427                         return NULL;
 428                 }
 429                 total += n;
 430         }
 431
 432         if (PyString_GET_SIZE(result) > total) {
 433                 if (_PyString_Resize(&result, total) < 0) {
 434                         /* This should never happen, but just in case */
 435                         Py_DECREF(result);
 436                         return NULL;
 437                 }
 438         }
 439         return result;
 440 }
 441
 442 static PyObject *
 443 fileio_read(PyFileIOObject *self, PyObject *args)
 444 {
 445         char *ptr;
 446         Py_ssize_t n;
 447         Py_ssize_t size = -1;
 448         PyObject *bytes;
 449
 450         if (self->fd < 0)
 451                 return err_closed();
 452         if (!self->readable)
 453                 return err_mode("reading");
 454
 455         if (!PyArg_ParseTuple(args, "|n", &size))
 456                 return NULL;
 457
 458         if (size < 0) {
 459                 return fileio_readall(self);
 460         }
 461
 462         bytes = PyString_FromStringAndSize(NULL, size);
 463         if (bytes == NULL)
 464                 return NULL;
 465         ptr = PyString_AS_STRING(bytes);
 466
 467         Py_BEGIN_ALLOW_THREADS
 468         errno = 0;
 469         n = read(self->fd, ptr, size);
 470         Py_END_ALLOW_THREADS
 471
 472         if (n < 0) {
 473                 if (errno == EAGAIN)
 474                         Py_RETURN_NONE;
 475                 PyErr_SetFromErrno(PyExc_IOError);
 476                 return NULL;
 477         }
 478
 479         if (n != size) {
 480                 if (_PyString_Resize(&bytes, n) < 0) {
 481                         Py_DECREF(bytes);
 482                         return NULL;
 483                 }
 484         }
 485
 486         return (PyObject *) bytes;
 487 }
 488
 489 static PyObject *
 490 fileio_write(PyFileIOObject *self, PyObject *args)
 491 {
 492         Py_ssize_t n;
 493         char *ptr;
 494
 495         if (self->fd < 0)
 496                 return err_closed();
 497         if (!self->writable)
 498                 return err_mode("writing");
 499
 500         if (!PyArg_ParseTuple(args, "s#", &ptr, &n))
 501                 return NULL;
 502
 503         Py_BEGIN_ALLOW_THREADS
 504         errno = 0;
 505         n = write(self->fd, ptr, n);
 506         Py_END_ALLOW_THREADS
 507
 508         if (n < 0) {
 509                 if (errno == EAGAIN)
 510                         Py_RETURN_NONE;
 511                 PyErr_SetFromErrno(PyExc_IOError);
 512                 return NULL;
 513         }
 514
 515         return PyLong_FromSsize_t(n);
 516 }
 517
 518 /* XXX Windows support below is likely incomplete */
 519
 520 #if defined(MS_WIN64) || defined(MS_WINDOWS)
 521 typedef PY_LONG_LONG Py_off_t;
 522 #else
 523 typedef off_t Py_off_t;
 524 #endif
 525
 526 /* Cribbed from posix_lseek() */
 527 static PyObject *
 528 portable_lseek(int fd, PyObject *posobj, int whence)
 529 {
 530         Py_off_t pos, res;
 531
 532 #ifdef SEEK_SET
 533         /* Turn 0, 1, 2 into SEEK_{SET,CUR,END} */
 534         switch (whence) {
 535 #if SEEK_SET != 0
 536         case 0: whence = SEEK_SET; break;
 537 #endif
 538 #if SEEK_CUR != 1
 539         case 1: whence = SEEK_CUR; break;
 540 #endif
 541 #if SEEL_END != 2
 542         case 2: whence = SEEK_END; break;
 543 #endif
 544         }
 545 #endif /* SEEK_SET */
 546
 547         if (posobj == NULL)
 548                 pos = 0;
 549         else {
 550                 if(PyFloat_Check(posobj)) {
 551                         PyErr_SetString(PyExc_TypeError, "an integer is required");
 552                         return NULL;
 553                 }
 554 #if defined(HAVE_LARGEFILE_SUPPORT)
 555                 pos = PyLong_AsLongLong(posobj);
 556 #else
 557                 pos = PyLong_AsLong(posobj);
 558 #endif
 559                 if (PyErr_Occurred())
 560                         return NULL;
 561         }
 562
 563         Py_BEGIN_ALLOW_THREADS
 564 #if defined(MS_WIN64) || defined(MS_WINDOWS)
 565         res = _lseeki64(fd, pos, whence);
 566 #else
 567         res = lseek(fd, pos, whence);
 568 #endif
 569         Py_END_ALLOW_THREADS
 570         if (res < 0)
 571                 return PyErr_SetFromErrno(PyExc_IOError);
 572
 573 #if defined(HAVE_LARGEFILE_SUPPORT)
 574         return PyLong_FromLongLong(res);
 575 #else
 576         return PyLong_FromLong(res);
 577 #endif
 578 }
 579
 580 static PyObject *
 581 fileio_seek(PyFileIOObject *self, PyObject *args)
 582 {
 583         PyObject *posobj;
 584         int whence = 0;
 585
 586         if (self->fd < 0)
 587                 return err_closed();
 588
 589         if (!PyArg_ParseTuple(args, "O|i", &posobj, &whence))
 590                 return NULL;
 591
 592         return portable_lseek(self->fd, posobj, whence);
 593 }
 594
 595 static PyObject *
 596 fileio_tell(PyFileIOObject *self, PyObject *args)
 597 {
 598         if (self->fd < 0)
 599                 return err_closed();
 600
 601         return portable_lseek(self->fd, NULL, 1);
 602 }
 603
 604 #ifdef HAVE_FTRUNCATE
 605 static PyObject *
 606 fileio_truncate(PyFileIOObject *self, PyObject *args)
 607 {
 608         PyObject *posobj = NULL;
 609         Py_off_t pos;
 610         int ret;
 611         int fd;
 612
 613         fd = self->fd;
 614         if (fd < 0)
 615                 return err_closed();
 616         if (!self->writable)
 617                 return err_mode("writing");
 618
 619         if (!PyArg_ParseTuple(args, "|O", &posobj))
 620                 return NULL;
 621
 622         if (posobj == Py_None || posobj == NULL) {
 623                 /* Get the current position. */
 624                 posobj = portable_lseek(fd, NULL, 1);
 625                 if (posobj == NULL)
 626                         return NULL;
 627         }
 628         else {
 629                 /* Move to the position to be truncated. */
 630                 posobj = portable_lseek(fd, posobj, 0);
 631         }
 632
 633 #if defined(HAVE_LARGEFILE_SUPPORT)
 634         pos = PyLong_AsLongLong(posobj);
 635 #else
 636         pos = PyLong_AsLong(posobj);
 637 #endif
 638         if (PyErr_Occurred())
 639                 return NULL;
 640
 641 #ifdef MS_WINDOWS
 642         /* MS _chsize doesn't work if newsize doesn't fit in 32 bits,
 643            so don't even try using it. */
 644         {
 645                 HANDLE hFile;
 646
 647                 /* Truncate.  Note that this may grow the file! */
 648                 Py_BEGIN_ALLOW_THREADS
 649                 errno = 0;
 650                 hFile = (HANDLE)_get_osfhandle(fd);
 651                 ret = hFile == (HANDLE)-1;
 652                 if (ret == 0) {
 653                         ret = SetEndOfFile(hFile) == 0;
 654                         if (ret)
 655                                 errno = EACCES;
 656                 }
 657                 Py_END_ALLOW_THREADS
 658         }
 659 #else
 660         Py_BEGIN_ALLOW_THREADS
 661         errno = 0;
 662         ret = ftruncate(fd, pos);
 663         Py_END_ALLOW_THREADS
 664 #endif /* !MS_WINDOWS */
 665
 666         if (ret != 0) {
 667                 PyErr_SetFromErrno(PyExc_IOError);
 668                 return NULL;
 669         }
 670
 671         return posobj;
 672 }
 673 #endif
 674
 675 static char *
 676 mode_string(PyFileIOObject *self)
 677 {
 678         if (self->readable) {
 679                 if (self->writable)
 680                         return "r+";
 681                 else
 682                         return "r";
 683         }
 684         else
 685                 return "w";
 686 }
 687
 688 static PyObject *
 689 fileio_repr(PyFileIOObject *self)
 690 {
 691         if (self->fd < 0)
 692                 return PyString_FromFormat("_fileio._FileIO(-1)");
 693
 694         return PyString_FromFormat("_fileio._FileIO(%d, '%s')",
 695                                    self->fd, mode_string(self));
 696 }
 697
 698 static PyObject *
 699 fileio_isatty(PyFileIOObject *self)
 700 {
 701         long res;
 702
 703         if (self->fd < 0)
 704                 return err_closed();
 705         Py_BEGIN_ALLOW_THREADS
 706         res = isatty(self->fd);
 707         Py_END_ALLOW_THREADS
 708         return PyBool_FromLong(res);
 709 }
 710
 711
 712 PyDoc_STRVAR(fileio_doc,
 713 "file(name: str[, mode: str]) -> file IO object\n"
 714 "\n"
 715 "Open a file.  The mode can be 'r', 'w' or 'a' for reading (default),\n"
 716 "writing or appending.  The file will be created if it doesn't exist\n"
 717 "when opened for writing or appending; it will be truncated when\n"
 718 "opened for writing.  Add a '+' to the mode to allow simultaneous\n"
 719 "reading and writing.");
 720
 721 PyDoc_STRVAR(read_doc,
 722 "read(size: int) -> bytes.  read at most size bytes, returned as bytes.\n"
 723 "\n"
 724 "Only makes one system call, so less data may be returned than requested\n"
 725 "In non-blocking mode, returns None if no data is available.\n"
 726 "On end-of-file, returns ''.");
 727
 728 PyDoc_STRVAR(readall_doc,
 729 "readall() -> bytes.  read all data from the file, returned as bytes.\n"
 730 "\n"
 731 "In non-blocking mode, returns as much as is immediately available,\n"
 732 "or None if no data is available.  On end-of-file, returns ''.");
 733
 734 PyDoc_STRVAR(write_doc,
 735 "write(b: bytes) -> int.  Write bytes b to file, return number written.\n"
 736 "\n"
 737 "Only makes one system call, so not all of the data may be written.\n"
 738 "The number of bytes actually written is returned.");
 739
 740 PyDoc_STRVAR(fileno_doc,
 741 "fileno() -> int. \"file descriptor\".\n"
 742 "\n"
 743 "This is needed for lower-level file interfaces, such the fcntl module.");
 744
 745 PyDoc_STRVAR(seek_doc,
 746 "seek(offset: int[, whence: int]) -> None.  Move to new file position.\n"
 747 "\n"
 748 "Argument offset is a byte count.  Optional argument whence defaults to\n"
 749 "0 (offset from start of file, offset should be >= 0); other values are 1\n"
 750 "(move relative to current position, positive or negative), and 2 (move\n"
 751 "relative to end of file, usually negative, although many platforms allow\n"
 752 "seeking beyond the end of a file)."
 753 "\n"
 754 "Note that not all file objects are seekable.");
 755
 756 #ifdef HAVE_FTRUNCATE
 757 PyDoc_STRVAR(truncate_doc,
 758 "truncate([size: int]) -> None.  Truncate the file to at most size bytes.\n"
 759 "\n"
 760 "Size defaults to the current file position, as returned by tell()."
 761 "The current file position is changed to the value of size.");
 762 #endif
 763
 764 PyDoc_STRVAR(tell_doc,
 765 "tell() -> int.  Current file position");
 766
 767 PyDoc_STRVAR(readinto_doc,
 768 "readinto() -> Undocumented.  Don't use this; it may go away.");
 769
 770 PyDoc_STRVAR(close_doc,
 771 "close() -> None.  Close the file.\n"
 772 "\n"
 773 "A closed file cannot be used for further I/O operations.  close() may be\n"
 774 "called more than once without error.  Changes the fileno to -1.");
 775
 776 PyDoc_STRVAR(isatty_doc,
 777 "isatty() -> bool.  True if the file is connected to a tty device.");
 778
 779 PyDoc_STRVAR(seekable_doc,
 780 "seekable() -> bool.  True if file supports random-access.");
 781
 782 PyDoc_STRVAR(readable_doc,
 783 "readable() -> bool.  True if file was opened in a read mode.");
 784
 785 PyDoc_STRVAR(writable_doc,
 786 "writable() -> bool.  True if file was opened in a write mode.");
 787
 788 static PyMethodDef fileio_methods[] = {
 789         {"read",     (PyCFunction)fileio_read,     METH_VARARGS, read_doc},
 790         {"readall",  (PyCFunction)fileio_readall,  METH_NOARGS,  readall_doc},
 791         {"readinto", (PyCFunction)fileio_readinto, METH_VARARGS, readinto_doc},
 792         {"write",    (PyCFunction)fileio_write,    METH_VARARGS, write_doc},
 793         {"seek",     (PyCFunction)fileio_seek,     METH_VARARGS, seek_doc},
 794         {"tell",     (PyCFunction)fileio_tell,     METH_VARARGS, tell_doc},
 795 #ifdef HAVE_FTRUNCATE
 796         {"truncate", (PyCFunction)fileio_truncate, METH_VARARGS, truncate_doc},
 797 #endif
 798         {"close",    (PyCFunction)fileio_close,    METH_NOARGS,  close_doc},
 799         {"seekable", (PyCFunction)fileio_seekable, METH_NOARGS,  seekable_doc},
 800         {"readable", (PyCFunction)fileio_readable, METH_NOARGS,  readable_doc},
 801         {"writable", (PyCFunction)fileio_writable, METH_NOARGS,  writable_doc},
 802         {"fileno",   (PyCFunction)fileio_fileno,   METH_NOARGS,  fileno_doc},
 803         {"isatty",   (PyCFunction)fileio_isatty,   METH_NOARGS,  isatty_doc},
 804         {NULL,       NULL}             /* sentinel */
 805 };
 806
 807 /* 'closed' and 'mode' are attributes for backwards compatibility reasons. */
 808
 809 static PyObject *
 810 get_closed(PyFileIOObject *self, void *closure)
 811 {
 812         return PyBool_FromLong((long)(self->fd < 0));
 813 }
 814
 815 static PyObject *
 816 get_mode(PyFileIOObject *self, void *closure)
 817 {
 818         return PyString_FromString(mode_string(self));
 819 }
 820
 821 static PyGetSetDef fileio_getsetlist[] = {
 822         {"closed", (getter)get_closed, NULL, "True if the file is closed"},
 823         {"mode", (getter)get_mode, NULL, "String giving the file mode"},
 824         {0},
 825 };
 826
 827 PyTypeObject PyFileIO_Type = {
 828         PyVarObject_HEAD_INIT(&PyType_Type, 0)
 829         "_FileIO",
 830         sizeof(PyFileIOObject),
 831         0,
 832         (destructor)fileio_dealloc,             /* tp_dealloc */
 833         0,                                      /* tp_print */
 834         0,                                      /* tp_getattr */
 835         0,                                      /* tp_setattr */
 836         0,                                      /* tp_compare */
 837         (reprfunc)fileio_repr,                  /* tp_repr */
 838         0,                                      /* tp_as_number */
 839         0,                                      /* tp_as_sequence */
 840         0,                                      /* tp_as_mapping */
 841         0,                                      /* tp_hash */
 842         0,                                      /* tp_call */
 843         0,                                      /* tp_str */
 844         PyObject_GenericGetAttr,                /* tp_getattro */
 845         0,                                      /* tp_setattro */
 846         0,                                      /* tp_as_buffer */
 847         Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
 848         fileio_doc,                             /* tp_doc */
 849         0,                                      /* tp_traverse */
 850         0,                                      /* tp_clear */
 851         0,                                      /* tp_richcompare */
 852         offsetof(PyFileIOObject, weakreflist),  /* tp_weaklistoffset */
 853         0,                                      /* tp_iter */
 854         0,                                      /* tp_iternext */
 855         fileio_methods,                         /* tp_methods */
 856         0,                                      /* tp_members */
 857         fileio_getsetlist,                      /* tp_getset */
 858         0,                                      /* tp_base */
 859         0,                                      /* tp_dict */
 860         0,                                      /* tp_descr_get */
 861         0,                                      /* tp_descr_set */
 862         0,                                      /* tp_dictoffset */
 863         fileio_init,                            /* tp_init */
 864         PyType_GenericAlloc,                    /* tp_alloc */
 865         fileio_new,                             /* tp_new */
 866         PyObject_Del,                           /* tp_free */
 867 };
 868
 869 static PyMethodDef module_methods[] = {
 870         {NULL, NULL}
 871 };
 872
 873 PyMODINIT_FUNC
 874 init_fileio(void)
 875 {
 876         PyObject *m;    /* a module object */
 877
 878         m = Py_InitModule3("_fileio", module_methods,
 879                            "Fast implementation of io.FileIO.");
 880         if (m == NULL)
 881                 return;
 882         if (PyType_Ready(&PyFileIO_Type) < 0)
 883                 return;
 884         Py_INCREF(&PyFileIO_Type);
 885         PyModule_AddObject(m, "_FileIO", (PyObject *) &PyFileIO_Type);
 886 }