diff options
Diffstat (limited to 'Lib/_pyio.py')
| -rw-r--r-- | Lib/_pyio.py | 344 |
1 files changed, 344 insertions, 0 deletions
diff --git a/Lib/_pyio.py b/Lib/_pyio.py index 1df44cc..400a56a 100644 --- a/Lib/_pyio.py +++ b/Lib/_pyio.py @@ -7,11 +7,16 @@ import abc import codecs import errno import array +import stat # Import _thread instead of threading to reduce startup cost try: from _thread import allocate_lock as Lock except ImportError: from _dummy_thread import allocate_lock as Lock +if os.name == 'win32': + from msvcrt import setmode as _setmode +else: + _setmode = None import io from io import (__all__, SEEK_SET, SEEK_CUR, SEEK_END) @@ -1378,6 +1383,345 @@ class BufferedRandom(BufferedWriter, BufferedReader): return BufferedWriter.write(self, b) +class FileIO(RawIOBase): + _fd = -1 + _created = False + _readable = False + _writable = False + _appending = False + _seekable = None + _closefd = True + + def __init__(self, file, mode='r', closefd=True, opener=None): + """Open a file. The mode can be 'r' (default), 'w', 'x' or 'a' for reading, + writing, exclusive creation or appending. The file will be created if it + doesn't exist when opened for writing or appending; it will be truncated + when opened for writing. A FileExistsError will be raised if it already + exists when opened for creating. Opening a file for creating implies + writing so this mode behaves in a similar way to 'w'. Add a '+' to the mode + to allow simultaneous reading and writing. A custom opener can be used by + passing a callable as *opener*. The underlying file descriptor for the file + object is then obtained by calling opener with (*name*, *flags*). + *opener* must return an open file descriptor (passing os.open as *opener* + results in functionality similar to passing None). + """ + if self._fd >= 0: + # Have to close the existing file first. + try: + if self._closefd: + os.close(self._fd) + finally: + self._fd = -1 + + if isinstance(file, float): + raise TypeError('integer argument expected, got float') + if isinstance(file, int): + fd = file + if fd < 0: + raise ValueError('negative file descriptor') + else: + fd = -1 + + if not isinstance(mode, str): + raise TypeError('invalid mode: %s' % (mode,)) + if not set(mode) <= set('xrwab+'): + raise ValueError('invalid mode: %s' % (mode,)) + if sum(c in 'rwax' for c in mode) != 1 or mode.count('+') > 1: + raise ValueError('Must have exactly one of create/read/write/append ' + 'mode and at most one plus') + + if 'x' in mode: + self._created = True + self._writable = True + flags = os.O_EXCL | os.O_CREAT + elif 'r' in mode: + self._readable = True + flags = 0 + elif 'w' in mode: + self._writable = True + flags = os.O_CREAT | os.O_TRUNC + elif 'a' in mode: + self._writable = True + self._appending = True + flags = os.O_APPEND | os.O_CREAT + + if '+' in mode: + self._readable = True + self._writable = True + + if self._readable and self._writable: + flags |= os.O_RDWR + elif self._readable: + flags |= os.O_RDONLY + else: + flags |= os.O_WRONLY + + flags |= getattr(os, 'O_BINARY', 0) + + noinherit_flag = (getattr(os, 'O_NOINHERIT', 0) or + getattr(os, 'O_CLOEXEC', 0)) + flags |= noinherit_flag + + owned_fd = None + try: + if fd < 0: + if not closefd: + raise ValueError('Cannot use closefd=False with file name') + if opener is None: + fd = os.open(file, flags, 0o666) + else: + fd = opener(file, flags) + if not isinstance(fd, int): + raise TypeError('expected integer from opener') + if fd < 0: + raise OSError('Negative file descriptor') + owned_fd = fd + if not noinherit_flag: + os.set_inheritable(fd, False) + + self._closefd = closefd + fdfstat = os.fstat(fd) + try: + if stat.S_ISDIR(fdfstat.st_mode): + raise IsADirectoryError(errno.EISDIR, + os.strerror(errno.EISDIR), file) + except AttributeError: + # Ignore the AttribueError if stat.S_ISDIR or errno.EISDIR + # don't exist. + pass + self._blksize = getattr(fdfstat, 'st_blksize', 0) + if self._blksize <= 1: + self._blksize = DEFAULT_BUFFER_SIZE + + if _setmode: + # don't translate newlines (\r\n <=> \n) + _setmode(fd, os.O_BINARY) + + self.name = file + if self._appending: + # For consistent behaviour, we explicitly seek to the + # end of file (otherwise, it might be done only on the + # first write()). + os.lseek(fd, 0, SEEK_END) + except: + if owned_fd is not None: + os.close(owned_fd) + raise + self._fd = fd + + def __del__(self): + if self._fd >= 0 and self._closefd and not self.closed: + import warnings + warnings.warn('unclosed file %r' % (self,), ResourceWarning, + stacklevel=2) + self.close() + + def __getstate__(self): + raise TypeError("cannot serialize '%s' object", self.__class__.__name__) + + def __repr__(self): + class_name = '%s.%s' % (self.__class__.__module__, + self.__class__.__qualname__) + if self.closed: + return '<%s [closed]>' % class_name + try: + name = self.name + except AttributeError: + return ('<%s fd=%d mode=%r closefd=%r>' % + (class_name, self._fd, self.mode, self._closefd)) + else: + return ('<%s name=%r mode=%r closefd=%r>' % + (class_name, name, self.mode, self._closefd)) + + def _checkReadable(self): + if not self._readable: + raise UnsupportedOperation('File not open for reading') + + def _checkWritable(self, msg=None): + if not self._writable: + raise UnsupportedOperation('File not open for writing') + + def read(self, size=None): + """Read at most size bytes, returned as bytes. + + Only makes one system call, so less data may be returned than requested + In non-blocking mode, returns None if no data is available. + Return an empty bytes object at EOF. + """ + self._checkClosed() + self._checkReadable() + if size is None or size < 0: + return self.readall() + try: + return os.read(self._fd, size) + except BlockingIOError: + return None + + def readall(self): + """Read all data from the file, returned as bytes. + + In non-blocking mode, returns as much as is immediately available, + or None if no data is available. Return an empty bytes object at EOF. + """ + self._checkClosed() + self._checkReadable() + bufsize = DEFAULT_BUFFER_SIZE + try: + pos = os.lseek(self._fd, 0, SEEK_CUR) + end = os.fstat(self._fd).st_size + if end >= pos: + bufsize = end - pos + 1 + except OSError: + pass + + result = bytearray() + while True: + if len(result) >= bufsize: + bufsize = len(result) + bufsize += max(bufsize, DEFAULT_BUFFER_SIZE) + n = bufsize - len(result) + try: + chunk = os.read(self._fd, n) + except BlockingIOError: + if result: + break + return None + if not chunk: # reached the end of the file + break + result += chunk + + return bytes(result) + + def readinto(self, b): + """Same as RawIOBase.readinto().""" + m = memoryview(b).cast('B') + data = self.read(len(m)) + n = len(data) + m[:n] = data + return n + + def write(self, b): + """Write bytes b to file, return number written. + + Only makes one system call, so not all of the data may be written. + The number of bytes actually written is returned. In non-blocking mode, + returns None if the write would block. + """ + self._checkClosed() + self._checkWritable() + try: + return os.write(self._fd, b) + except BlockingIOError: + return None + + def seek(self, pos, whence=SEEK_SET): + """Move to new file position. + + Argument offset is a byte count. Optional argument whence defaults to + SEEK_SET or 0 (offset from start of file, offset should be >= 0); other values + are SEEK_CUR or 1 (move relative to current position, positive or negative), + and SEEK_END or 2 (move relative to end of file, usually negative, although + many platforms allow seeking beyond the end of a file). + + Note that not all file objects are seekable. + """ + if isinstance(pos, float): + raise TypeError('an integer is required') + self._checkClosed() + return os.lseek(self._fd, pos, whence) + + def tell(self): + """tell() -> int. Current file position. + + Can raise OSError for non seekable files.""" + self._checkClosed() + return os.lseek(self._fd, 0, SEEK_CUR) + + def truncate(self, size=None): + """Truncate the file to at most size bytes. + + Size defaults to the current file position, as returned by tell(). + The current file position is changed to the value of size. + """ + self._checkClosed() + self._checkWritable() + if size is None: + size = self.tell() + os.ftruncate(self._fd, size) + return size + + def close(self): + """Close the file. + + A closed file cannot be used for further I/O operations. close() may be + called more than once without error. + """ + if not self.closed: + try: + if self._closefd: + os.close(self._fd) + finally: + super().close() + + def seekable(self): + """True if file supports random-access.""" + self._checkClosed() + if self._seekable is None: + try: + self.tell() + except OSError: + self._seekable = False + else: + self._seekable = True + return self._seekable + + def readable(self): + """True if file was opened in a read mode.""" + self._checkClosed() + return self._readable + + def writable(self): + """True if file was opened in a write mode.""" + self._checkClosed() + return self._writable + + def fileno(self): + """Return the underlying file descriptor (an integer).""" + self._checkClosed() + return self._fd + + def isatty(self): + """True if the file is connected to a TTY device.""" + self._checkClosed() + return os.isatty(self._fd) + + @property + def closefd(self): + """True if the file descriptor will be closed by close().""" + return self._closefd + + @property + def mode(self): + """String giving the file mode""" + if self._created: + if self._readable: + return 'xb+' + else: + return 'xb' + elif self._appending: + if self._readable: + return 'ab+' + else: + return 'ab' + elif self._readable: + if self._writable: + return 'rb+' + else: + return 'rb' + else: + return 'wb' + + class TextIOBase(IOBase): """Base class for text I/O. |