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                 self->fd = -1;
  65                 Py_RETURN_NONE;
  66         }
  67         errno = internal_close(self);
  68         if (errno < 0) {
  69                 PyErr_SetFromErrno(PyExc_IOError);
  70                 return NULL;
  71         }
  72
  73         Py_RETURN_NONE;
  74 }
  75
  76 static PyObject *
  77 fileio_new(PyTypeObject *type, PyObject *args, PyObject *kews)
  78 {
  79         PyFileIOObject *self;
  80
  81         assert(type != NULL && type->tp_alloc != NULL);
  82
  83         self = (PyFileIOObject *) type->tp_alloc(type, 0);
  84         if (self != NULL) {
  85                 self->fd = -1;
  86                 self->readable = 0;
  87                 self->writable = 0;
  88                 self->seekable = -1;
  89                 self->closefd = 1;
  90                 self->weakreflist = NULL;
  91         }
  92
  93         return (PyObject *) self;
  94 }
  95
  96 /* On Unix, open will succeed for directories.
  97    In Python, there should be no file objects referring to
  98    directories, so we need a check.  */
  99
 100 static int
 101 dircheck(PyFileIOObject* self, char *name)
 102 {
 103 #if defined(HAVE_FSTAT) && defined(S_IFDIR) && defined(EISDIR)
 104         struct stat buf;
 105         if (self->fd < 0)
 106                 return 0;
 107         if (fstat(self->fd, &buf) == 0 && S_ISDIR(buf.st_mode)) {
 108                 char *msg = strerror(EISDIR);
 109                 PyObject *exc;
 110                 internal_close(self);
 111
 112                 exc = PyObject_CallFunction(PyExc_IOError, "(iss)",
 113                                             EISDIR, msg, name);
 114                 PyErr_SetObject(PyExc_IOError, exc);
 115                 Py_XDECREF(exc);
 116                 return -1;
 117         }
 118 #endif
 119         return 0;
 120 }
 121
 122 static int
 123 check_fd(int fd)
 124 {
 125 #if defined(HAVE_FSTAT)
 126         struct stat buf;
 127         if (fstat(fd, &buf) < 0 && errno == EBADF) {
 128                 PyObject *exc;
 129                 char *msg = strerror(EBADF);
 130                 exc = PyObject_CallFunction(PyExc_OSError, "(is)",
 131                                             EBADF, msg);
 132                 PyErr_SetObject(PyExc_OSError, exc);
 133                 Py_XDECREF(exc);
 134                 return -1;
 135         }
 136 #endif
 137         return 0;
 138 }
 139
 140
 141 static int
 142 fileio_init(PyObject *oself, PyObject *args, PyObject *kwds)
 143 {
 144         PyFileIOObject *self = (PyFileIOObject *) oself;
 145         static char *kwlist[] = {"file", "mode", "closefd", NULL};
 146         char *name = NULL;
 147         char *mode = "r";
 148         char *s;
 149 #ifdef MS_WINDOWS
 150         Py_UNICODE *widename = NULL;
 151 #endif
 152         int ret = 0;
 153         int rwa = 0, plus = 0, append = 0;
 154         int flags = 0;
 155         int fd = -1;
 156         int closefd = 1;
 157
 158         assert(PyFileIO_Check(oself));
 159         if (self->fd >= 0) {
 160                 /* Have to close the existing file first. */
 161                 if (internal_close(self) < 0)
 162                         return -1;
 163         }
 164
 165         if (PyArg_ParseTupleAndKeywords(args, kwds, "i|si:fileio",
 166                                         kwlist, &fd, &mode, &closefd)) {
 167                 if (fd < 0) {
 168                         PyErr_SetString(PyExc_ValueError,
 169                                         "Negative filedescriptor");
 170                         return -1;
 171                 }
 172                 if (check_fd(fd))
 173                         return -1;
 174         }
 175         else {
 176                 PyErr_Clear();
 177
 178 #ifdef Py_WIN_WIDE_FILENAMES
 179             if (GetVersion() < 0x80000000) {
 180                 /* On NT, so wide API available */
 181                 PyObject *po;
 182                 if (PyArg_ParseTupleAndKeywords(args, kwds, "U|si:fileio",
 183                                                 kwlist, &po, &mode, &closefd)
 184                                                 ) {
 185                         widename = PyUnicode_AS_UNICODE(po);
 186                 } else {
 187                         /* Drop the argument parsing error as narrow
 188                            strings are also valid. */
 189                         PyErr_Clear();
 190                 }
 191             }
 192             if (widename == NULL)
 193 #endif
 194             {
 195                 if (!PyArg_ParseTupleAndKeywords(args, kwds, "et|si:fileio",
 196                                                  kwlist,
 197                                                  Py_FileSystemDefaultEncoding,
 198                                                  &name, &mode, &closefd))
 199                         return -1;
 200             }
 201         }
 202
 203         s = mode;
 204         while (*s) {
 205                 switch (*s++) {
 206                 case 'r':
 207                         if (rwa) {
 208                         bad_mode:
 209                                 PyErr_SetString(PyExc_ValueError,
 210                                                 "Must have exactly one of read/write/append mode");
 211                                 goto error;
 212                         }
 213                         rwa = 1;
 214                         self->readable = 1;
 215                         break;
 216                 case 'w':
 217                         if (rwa)
 218                                 goto bad_mode;
 219                         rwa = 1;
 220                         self->writable = 1;
 221                         flags |= O_CREAT | O_TRUNC;
 222                         break;
 223                 case 'a':
 224                         if (rwa)
 225                                 goto bad_mode;
 226                         rwa = 1;
 227                         self->writable = 1;
 228                         flags |= O_CREAT;
 229                         append = 1;
 230                         break;
 231                 case 'b':
 232                         break;
 233                 case '+':
 234                         if (plus)
 235                                 goto bad_mode;
 236                         self->readable = self->writable = 1;
 237                         plus = 1;
 238                         break;
 239                 default:
 240                         PyErr_Format(PyExc_ValueError,
 241                                      "invalid mode: %.200s", mode);
 242                         goto error;
 243                 }
 244         }
 245
 246         if (!rwa)
 247                 goto bad_mode;
 248
 249         if (self->readable && self->writable)
 250                 flags |= O_RDWR;
 251         else if (self->readable)
 252                 flags |= O_RDONLY;
 253         else
 254                 flags |= O_WRONLY;
 255
 256 #ifdef O_BINARY
 257         flags |= O_BINARY;
 258 #endif
 259
 260 #ifdef O_APPEND
 261         if (append)
 262                 flags |= O_APPEND;
 263 #endif
 264
 265         if (fd >= 0) {
 266                 self->fd = fd;
 267                 self->closefd = closefd;
 268         }
 269         else {
 270                 self->closefd = 1;
 271                 if (!closefd) {
 272                         PyErr_SetString(PyExc_ValueError,
 273                             "Cannot use closefd=False with file name");
 274                         goto error;
 275                 }
 276
 277                 Py_BEGIN_ALLOW_THREADS
 278                 errno = 0;
 279 #ifdef MS_WINDOWS
 280                 if (widename != NULL)
 281                         self->fd = _wopen(widename, flags, 0666);
 282                 else
 283 #endif
 284                         self->fd = open(name, flags, 0666);
 285                 Py_END_ALLOW_THREADS
 286                 if (self->fd < 0) {
 287 #ifdef MS_WINDOWS
 288                         if (widename != NULL)
 289                                 PyErr_SetFromErrnoWithUnicodeFilename(PyExc_IOError, widename);
 290                         else
 291 #endif
 292                                 PyErr_SetFromErrnoWithFilename(PyExc_IOError, name);
 293                         goto error;
 294                 }
 295                 if(dircheck(self, name) < 0)
 296                         goto error;
 297         }
 298
 299         goto done;
 300
 301  error:
 302         ret = -1;
 303
 304  done:
 305         PyMem_Free(name);
 306         return ret;
 307 }
 308
 309 static void
 310 fileio_dealloc(PyFileIOObject *self)
 311 {
 312         if (self->weakreflist != NULL)
 313                 PyObject_ClearWeakRefs((PyObject *) self);
 314
 315         if (self->fd >= 0 && self->closefd) {
 316                 errno = internal_close(self);
 317                 if (errno < 0) {
 318                         PySys_WriteStderr("close failed: [Errno %d] %s\n",
 319                                           errno, strerror(errno));
 320                 }
 321         }
 322
 323         Py_TYPE(self)->tp_free((PyObject *)self);
 324 }
 325
 326 static PyObject *
 327 err_closed(void)
 328 {
 329         PyErr_SetString(PyExc_ValueError, "I/O operation on closed file");
 330         return NULL;
 331 }
 332
 333 static PyObject *
 334 err_mode(char *action)
 335 {
 336         PyErr_Format(PyExc_ValueError, "File not open for %s", action);
 337         return NULL;
 338 }
 339
 340 static PyObject *
 341 fileio_fileno(PyFileIOObject *self)
 342 {
 343         if (self->fd < 0)
 344                 return err_closed();
 345         return PyInt_FromLong((long) self->fd);
 346 }
 347
 348 static PyObject *
 349 fileio_readable(PyFileIOObject *self)
 350 {
 351         if (self->fd < 0)
 352                 return err_closed();
 353         return PyBool_FromLong((long) self->readable);
 354 }
 355
 356 static PyObject *
 357 fileio_writable(PyFileIOObject *self)
 358 {
 359         if (self->fd < 0)
 360                 return err_closed();
 361         return PyBool_FromLong((long) self->writable);
 362 }
 363
 364 static PyObject *
 365 fileio_seekable(PyFileIOObject *self)
 366 {
 367         if (self->fd < 0)
 368                 return err_closed();
 369         if (self->seekable < 0) {
 370                 int ret;
 371                 Py_BEGIN_ALLOW_THREADS
 372                 ret = lseek(self->fd, 0, SEEK_CUR);
 373                 Py_END_ALLOW_THREADS
 374                 if (ret < 0)
 375                         self->seekable = 0;
 376                 else
 377                         self->seekable = 1;
 378         }
 379         return PyBool_FromLong((long) self->seekable);
 380 }
 381
 382 static PyObject *
 383 fileio_readinto(PyFileIOObject *self, PyObject *args)
 384 {
 385         Py_buffer pbuf;
 386         Py_ssize_t n;
 387
 388         if (self->fd < 0)
 389                 return err_closed();
 390         if (!self->readable)
 391                 return err_mode("reading");
 392
 393         if (!PyArg_ParseTuple(args, "w*", &pbuf))
 394                 return NULL;
 395
 396         Py_BEGIN_ALLOW_THREADS
 397         errno = 0;
 398         n = read(self->fd, pbuf.buf, pbuf.len);
 399         Py_END_ALLOW_THREADS
 400         PyBuffer_Release(&pbuf);
 401         if (n < 0) {
 402                 if (errno == EAGAIN)
 403                         Py_RETURN_NONE;
 404                 PyErr_SetFromErrno(PyExc_IOError);
 405                 return NULL;
 406         }
 407
 408         return PyLong_FromSsize_t(n);
 409 }
 410
 411 #define DEFAULT_BUFFER_SIZE (8*1024)
 412
 413 static PyObject *
 414 fileio_readall(PyFileIOObject *self)
 415 {
 416         PyObject *result;
 417         Py_ssize_t total = 0;
 418         int n;
 419
 420         result = PyString_FromStringAndSize(NULL, DEFAULT_BUFFER_SIZE);
 421         if (result == NULL)
 422                 return NULL;
 423
 424         while (1) {
 425                 Py_ssize_t newsize = total + DEFAULT_BUFFER_SIZE;
 426                 if (PyString_GET_SIZE(result) < newsize) {
 427                         if (_PyString_Resize(&result, newsize) < 0) {
 428                                 if (total == 0) {
 429                                         Py_DECREF(result);
 430                                         return NULL;
 431                                 }
 432                                 PyErr_Clear();
 433                                 break;
 434                         }
 435                 }
 436                 Py_BEGIN_ALLOW_THREADS
 437                 errno = 0;
 438                 n = read(self->fd,
 439                          PyString_AS_STRING(result) + total,
 440                          newsize - total);
 441                 Py_END_ALLOW_THREADS
 442                 if (n == 0)
 443                         break;
 444                 if (n < 0) {
 445                         if (total > 0)
 446                                 break;
 447                         if (errno == EAGAIN) {
 448                                 Py_DECREF(result);
 449                                 Py_RETURN_NONE;
 450                         }
 451                         Py_DECREF(result);
 452                         PyErr_SetFromErrno(PyExc_IOError);
 453                         return NULL;
 454                 }
 455                 total += n;
 456         }
 457
 458         if (PyString_GET_SIZE(result) > total) {
 459                 if (_PyString_Resize(&result, total) < 0) {
 460                         /* This should never happen, but just in case */
 461                         Py_DECREF(result);
 462                         return NULL;
 463                 }
 464         }
 465         return result;
 466 }
 467
 468 static PyObject *
 469 fileio_read(PyFileIOObject *self, PyObject *args)
 470 {
 471         char *ptr;
 472         Py_ssize_t n;
 473         Py_ssize_t size = -1;
 474         PyObject *bytes;
 475
 476         if (self->fd < 0)
 477                 return err_closed();
 478         if (!self->readable)
 479                 return err_mode("reading");
 480
 481         if (!PyArg_ParseTuple(args, "|n", &size))
 482                 return NULL;
 483
 484         if (size < 0) {
 485                 return fileio_readall(self);
 486         }
 487
 488         bytes = PyString_FromStringAndSize(NULL, size);
 489         if (bytes == NULL)
 490                 return NULL;
 491         ptr = PyString_AS_STRING(bytes);
 492
 493         Py_BEGIN_ALLOW_THREADS
 494         errno = 0;
 495         n = read(self->fd, ptr, size);
 496         Py_END_ALLOW_THREADS
 497
 498         if (n < 0) {
 499                 if (errno == EAGAIN)
 500                         Py_RETURN_NONE;
 501                 PyErr_SetFromErrno(PyExc_IOError);
 502                 return NULL;
 503         }
 504
 505         if (n != size) {
 506                 if (_PyString_Resize(&bytes, n) < 0) {
 507                         Py_DECREF(bytes);
 508                         return NULL;
 509                 }
 510         }
 511
 512         return (PyObject *) bytes;
 513 }
 514
 515 static PyObject *
 516 fileio_write(PyFileIOObject *self, PyObject *args)
 517 {
 518         Py_buffer pbuf;
 519         Py_ssize_t n;
 520
 521         if (self->fd < 0)
 522                 return err_closed();
 523         if (!self->writable)
 524                 return err_mode("writing");
 525
 526         if (!PyArg_ParseTuple(args, "s*", &pbuf))
 527                 return NULL;
 528
 529         Py_BEGIN_ALLOW_THREADS
 530         errno = 0;
 531         n = write(self->fd, pbuf.buf, pbuf.len);
 532         Py_END_ALLOW_THREADS
 533
 534         PyBuffer_Release(&pbuf);
 535
 536         if (n < 0) {
 537                 if (errno == EAGAIN)
 538                         Py_RETURN_NONE;
 539                 PyErr_SetFromErrno(PyExc_IOError);
 540                 return NULL;
 541         }
 542
 543         return PyLong_FromSsize_t(n);
 544 }
 545
 546 /* XXX Windows support below is likely incomplete */
 547
 548 #if defined(MS_WIN64) || defined(MS_WINDOWS)
 549 typedef PY_LONG_LONG Py_off_t;
 550 #else
 551 typedef off_t Py_off_t;
 552 #endif
 553
 554 /* Cribbed from posix_lseek() */
 555 static PyObject *
 556 portable_lseek(int fd, PyObject *posobj, int whence)
 557 {
 558         Py_off_t pos, res;
 559
 560 #ifdef SEEK_SET
 561         /* Turn 0, 1, 2 into SEEK_{SET,CUR,END} */
 562         switch (whence) {
 563 #if SEEK_SET != 0
 564         case 0: whence = SEEK_SET; break;
 565 #endif
 566 #if SEEK_CUR != 1
 567         case 1: whence = SEEK_CUR; break;
 568 #endif
 569 #if SEEL_END != 2
 570         case 2: whence = SEEK_END; break;
 571 #endif
 572         }
 573 #endif /* SEEK_SET */
 574
 575         if (posobj == NULL)
 576                 pos = 0;
 577         else {
 578                 if(PyFloat_Check(posobj)) {
 579                         PyErr_SetString(PyExc_TypeError, "an integer is required");
 580                         return NULL;
 581                 }
 582 #if defined(HAVE_LARGEFILE_SUPPORT)
 583                 pos = PyLong_AsLongLong(posobj);
 584 #else
 585                 pos = PyLong_AsLong(posobj);
 586 #endif
 587                 if (PyErr_Occurred())
 588                         return NULL;
 589         }
 590
 591         Py_BEGIN_ALLOW_THREADS
 592 #if defined(MS_WIN64) || defined(MS_WINDOWS)
 593         res = _lseeki64(fd, pos, whence);
 594 #else
 595         res = lseek(fd, pos, whence);
 596 #endif
 597         Py_END_ALLOW_THREADS
 598         if (res < 0)
 599                 return PyErr_SetFromErrno(PyExc_IOError);
 600
 601 #if defined(HAVE_LARGEFILE_SUPPORT)
 602         return PyLong_FromLongLong(res);
 603 #else
 604         return PyLong_FromLong(res);
 605 #endif
 606 }
 607
 608 static PyObject *
 609 fileio_seek(PyFileIOObject *self, PyObject *args)
 610 {
 611         PyObject *posobj;
 612         int whence = 0;
 613
 614         if (self->fd < 0)
 615                 return err_closed();
 616
 617         if (!PyArg_ParseTuple(args, "O|i", &posobj, &whence))
 618                 return NULL;
 619
 620         return portable_lseek(self->fd, posobj, whence);
 621 }
 622
 623 static PyObject *
 624 fileio_tell(PyFileIOObject *self, PyObject *args)
 625 {
 626         if (self->fd < 0)
 627                 return err_closed();
 628
 629         return portable_lseek(self->fd, NULL, 1);
 630 }
 631
 632 #ifdef HAVE_FTRUNCATE
 633 static PyObject *
 634 fileio_truncate(PyFileIOObject *self, PyObject *args)
 635 {
 636         PyObject *posobj = NULL;
 637         Py_off_t pos;
 638         int ret;
 639         int fd;
 640
 641         fd = self->fd;
 642         if (fd < 0)
 643                 return err_closed();
 644         if (!self->writable)
 645                 return err_mode("writing");
 646
 647         if (!PyArg_ParseTuple(args, "|O", &posobj))
 648                 return NULL;
 649
 650         if (posobj == Py_None || posobj == NULL) {
 651                 /* Get the current position. */
 652                 posobj = portable_lseek(fd, NULL, 1);
 653                 if (posobj == NULL)
 654                         return NULL;
 655         }
 656         else {
 657                 /* Move to the position to be truncated. */
 658                 posobj = portable_lseek(fd, posobj, 0);
 659         }
 660
 661 #if defined(HAVE_LARGEFILE_SUPPORT)
 662         pos = PyLong_AsLongLong(posobj);
 663 #else
 664         pos = PyLong_AsLong(posobj);
 665 #endif
 666         if (PyErr_Occurred())
 667                 return NULL;
 668
 669 #ifdef MS_WINDOWS
 670         /* MS _chsize doesn't work if newsize doesn't fit in 32 bits,
 671            so don't even try using it. */
 672         {
 673                 HANDLE hFile;
 674
 675                 /* Truncate.  Note that this may grow the file! */
 676                 Py_BEGIN_ALLOW_THREADS
 677                 errno = 0;
 678                 hFile = (HANDLE)_get_osfhandle(fd);
 679                 ret = hFile == (HANDLE)-1;
 680                 if (ret == 0) {
 681                         ret = SetEndOfFile(hFile) == 0;
 682                         if (ret)
 683                                 errno = EACCES;
 684                 }
 685                 Py_END_ALLOW_THREADS
 686         }
 687 #else
 688         Py_BEGIN_ALLOW_THREADS
 689         errno = 0;
 690         ret = ftruncate(fd, pos);
 691         Py_END_ALLOW_THREADS
 692 #endif /* !MS_WINDOWS */
 693
 694         if (ret != 0) {
 695                 PyErr_SetFromErrno(PyExc_IOError);
 696                 return NULL;
 697         }
 698
 699         return posobj;
 700 }
 701 #endif
 702
 703 static char *
 704 mode_string(PyFileIOObject *self)
 705 {
 706         if (self->readable) {
 707                 if (self->writable)
 708                         return "rb+";
 709                 else
 710                         return "rb";
 711         }
 712         else
 713                 return "wb";
 714 }
 715
 716 static PyObject *
 717 fileio_repr(PyFileIOObject *self)
 718 {
 719         if (self->fd < 0)
 720                 return PyString_FromFormat("_fileio._FileIO(-1)");
 721
 722         return PyString_FromFormat("_fileio._FileIO(%d, '%s')",
 723                                    self->fd, mode_string(self));
 724 }
 725
 726 static PyObject *
 727 fileio_isatty(PyFileIOObject *self)
 728 {
 729         long res;
 730
 731         if (self->fd < 0)
 732                 return err_closed();
 733         Py_BEGIN_ALLOW_THREADS
 734         res = isatty(self->fd);
 735         Py_END_ALLOW_THREADS
 736         return PyBool_FromLong(res);
 737 }
 738
 739
 740 PyDoc_STRVAR(fileio_doc,
 741 "file(name: str[, mode: str]) -> file IO object\n"
 742 "\n"
 743 "Open a file.  The mode can be 'r', 'w' or 'a' for reading (default),\n"
 744 "writing or appending.  The file will be created if it doesn't exist\n"
 745 "when opened for writing or appending; it will be truncated when\n"
 746 "opened for writing.  Add a '+' to the mode to allow simultaneous\n"
 747 "reading and writing.");
 748
 749 PyDoc_STRVAR(read_doc,
 750 "read(size: int) -> bytes.  read at most size bytes, returned as bytes.\n"
 751 "\n"
 752 "Only makes one system call, so less data may be returned than requested\n"
 753 "In non-blocking mode, returns None if no data is available.\n"
 754 "On end-of-file, returns ''.");
 755
 756 PyDoc_STRVAR(readall_doc,
 757 "readall() -> bytes.  read all data from the file, returned as bytes.\n"
 758 "\n"
 759 "In non-blocking mode, returns as much as is immediately available,\n"
 760 "or None if no data is available.  On end-of-file, returns ''.");
 761
 762 PyDoc_STRVAR(write_doc,
 763 "write(b: bytes) -> int.  Write bytes b to file, return number written.\n"
 764 "\n"
 765 "Only makes one system call, so not all of the data may be written.\n"
 766 "The number of bytes actually written is returned.");
 767
 768 PyDoc_STRVAR(fileno_doc,
 769 "fileno() -> int. \"file descriptor\".\n"
 770 "\n"
 771 "This is needed for lower-level file interfaces, such the fcntl module.");
 772
 773 PyDoc_STRVAR(seek_doc,
 774 "seek(offset: int[, whence: int]) -> None.  Move to new file position.\n"
 775 "\n"
 776 "Argument offset is a byte count.  Optional argument whence defaults to\n"
 777 "0 (offset from start of file, offset should be >= 0); other values are 1\n"
 778 "(move relative to current position, positive or negative), and 2 (move\n"
 779 "relative to end of file, usually negative, although many platforms allow\n"
 780 "seeking beyond the end of a file)."
 781 "\n"
 782 "Note that not all file objects are seekable.");
 783
 784 #ifdef HAVE_FTRUNCATE
 785 PyDoc_STRVAR(truncate_doc,
 786 "truncate([size: int]) -> None.  Truncate the file to at most size bytes.\n"
 787 "\n"
 788 "Size defaults to the current file position, as returned by tell()."
 789 "The current file position is changed to the value of size.");
 790 #endif
 791
 792 PyDoc_STRVAR(tell_doc,
 793 "tell() -> int.  Current file position");
 794
 795 PyDoc_STRVAR(readinto_doc,
 796 "readinto() -> Undocumented.  Don't use this; it may go away.");
 797
 798 PyDoc_STRVAR(close_doc,
 799 "close() -> None.  Close the file.\n"
 800 "\n"
 801 "A closed file cannot be used for further I/O operations.  close() may be\n"
 802 "called more than once without error.  Changes the fileno to -1.");
 803
 804 PyDoc_STRVAR(isatty_doc,
 805 "isatty() -> bool.  True if the file is connected to a tty device.");
 806
 807 PyDoc_STRVAR(seekable_doc,
 808 "seekable() -> bool.  True if file supports random-access.");
 809
 810 PyDoc_STRVAR(readable_doc,
 811 "readable() -> bool.  True if file was opened in a read mode.");
 812
 813 PyDoc_STRVAR(writable_doc,
 814 "writable() -> bool.  True if file was opened in a write mode.");
 815
 816 static PyMethodDef fileio_methods[] = {
 817         {"read",     (PyCFunction)fileio_read,     METH_VARARGS, read_doc},
 818         {"readall",  (PyCFunction)fileio_readall,  METH_NOARGS,  readall_doc},
 819         {"readinto", (PyCFunction)fileio_readinto, METH_VARARGS, readinto_doc},
 820         {"write",    (PyCFunction)fileio_write,    METH_VARARGS, write_doc},
 821         {"seek",     (PyCFunction)fileio_seek,     METH_VARARGS, seek_doc},
 822         {"tell",     (PyCFunction)fileio_tell,     METH_VARARGS, tell_doc},
 823 #ifdef HAVE_FTRUNCATE
 824         {"truncate", (PyCFunction)fileio_truncate, METH_VARARGS, truncate_doc},
 825 #endif
 826         {"close",    (PyCFunction)fileio_close,    METH_NOARGS,  close_doc},
 827         {"seekable", (PyCFunction)fileio_seekable, METH_NOARGS,  seekable_doc},
 828         {"readable", (PyCFunction)fileio_readable, METH_NOARGS,  readable_doc},
 829         {"writable", (PyCFunction)fileio_writable, METH_NOARGS,  writable_doc},
 830         {"fileno",   (PyCFunction)fileio_fileno,   METH_NOARGS,  fileno_doc},
 831         {"isatty",   (PyCFunction)fileio_isatty,   METH_NOARGS,  isatty_doc},
 832         {NULL,       NULL}             /* sentinel */
 833 };
 834
 835 /* 'closed' and 'mode' are attributes for backwards compatibility reasons. */
 836
 837 static PyObject *
 838 get_closed(PyFileIOObject *self, void *closure)
 839 {
 840         return PyBool_FromLong((long)(self->fd < 0));
 841 }
 842
 843 static PyObject *
 844 get_closefd(PyFileIOObject *self, void *closure)
 845 {
 846         return PyBool_FromLong((long)(self->closefd));
 847 }
 848
 849 static PyObject *
 850 get_mode(PyFileIOObject *self, void *closure)
 851 {
 852         return PyString_FromString(mode_string(self));
 853 }
 854
 855 static PyGetSetDef fileio_getsetlist[] = {
 856         {"closed", (getter)get_closed, NULL, "True if the file is closed"},
 857         {"closefd", (getter)get_closefd, NULL,
 858                 "True if the file descriptor will be closed"},
 859         {"mode", (getter)get_mode, NULL, "String giving the file mode"},
 860         {0},
 861 };
 862
 863 PyTypeObject PyFileIO_Type = {
 864         PyVarObject_HEAD_INIT(NULL, 0)
 865         "_FileIO",
 866         sizeof(PyFileIOObject),
 867         0,
 868         (destructor)fileio_dealloc,             /* tp_dealloc */
 869         0,                                      /* tp_print */
 870         0,                                      /* tp_getattr */
 871         0,                                      /* tp_setattr */
 872         0,                                      /* tp_compare */
 873         (reprfunc)fileio_repr,                  /* tp_repr */
 874         0,                                      /* tp_as_number */
 875         0,                                      /* tp_as_sequence */
 876         0,                                      /* tp_as_mapping */
 877         0,                                      /* tp_hash */
 878         0,                                      /* tp_call */
 879         0,                                      /* tp_str */
 880         PyObject_GenericGetAttr,                /* tp_getattro */
 881         0,                                      /* tp_setattro */
 882         0,                                      /* tp_as_buffer */
 883         Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE, /* tp_flags */
 884         fileio_doc,                             /* tp_doc */
 885         0,                                      /* tp_traverse */
 886         0,                                      /* tp_clear */
 887         0,                                      /* tp_richcompare */
 888         offsetof(PyFileIOObject, weakreflist),  /* tp_weaklistoffset */
 889         0,                                      /* tp_iter */
 890         0,                                      /* tp_iternext */
 891         fileio_methods,                         /* tp_methods */
 892         0,                                      /* tp_members */
 893         fileio_getsetlist,                      /* tp_getset */
 894         0,                                      /* tp_base */
 895         0,                                      /* tp_dict */
 896         0,                                      /* tp_descr_get */
 897         0,                                      /* tp_descr_set */
 898         0,                                      /* tp_dictoffset */
 899         fileio_init,                            /* tp_init */
 900         PyType_GenericAlloc,                    /* tp_alloc */
 901         fileio_new,                             /* tp_new */
 902         PyObject_Del,                           /* tp_free */
 903 };
 904
 905 static PyMethodDef module_methods[] = {
 906         {NULL, NULL}
 907 };
 908
 909 PyMODINIT_FUNC
 910 init_fileio(void)
 911 {
 912         PyObject *m;    /* a module object */
 913
 914         m = Py_InitModule3("_fileio", module_methods,
 915                            "Fast implementation of io.FileIO.");
 916         if (m == NULL)
 917                 return;
 918         if (PyType_Ready(&PyFileIO_Type) < 0)
 919                 return;
 920         Py_INCREF(&PyFileIO_Type);
 921         PyModule_AddObject(m, "_FileIO", (PyObject *) &PyFileIO_Type);
 922 }