Poodletooth-iLand/panda/python/Lib/site-packages/gevent/os.py
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2015-05-18 22:11:33 -04:00

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Python
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"""
This module provides cooperative versions of os.read() and os.write().
On Posix platforms this uses non-blocking IO, on Windows a threadpool
is used.
"""
from __future__ import absolute_import
import os
import sys
from gevent.hub import get_hub, reinit
import errno
EAGAIN = getattr(errno, 'EAGAIN', 11)
try:
import fcntl
except ImportError:
fcntl = None
__implements__ = ['fork']
__extensions__ = ['tp_read', 'tp_write']
_read = os.read
_write = os.write
ignored_errors = [EAGAIN, errno.EINTR]
if fcntl:
__extensions__ += ['make_nonblocking', 'nb_read', 'nb_write']
def make_nonblocking(fd):
flags = fcntl.fcntl(fd, fcntl.F_GETFL, 0)
if not bool(flags & os.O_NONBLOCK):
fcntl.fcntl(fd, fcntl.F_SETFL, flags | os.O_NONBLOCK)
return True
def nb_read(fd, n):
"""Read up to `n` bytes from file descriptor `fd`. Return a string
containing the bytes read. If end-of-file is reached, an empty string
is returned.
The descriptor must be in non-blocking mode.
"""
hub, event = None, None
while True:
try:
return _read(fd, n)
except OSError, e:
if e.errno not in ignored_errors:
raise
sys.exc_clear()
if hub is None:
hub = get_hub()
event = hub.loop.io(fd, 1)
hub.wait(event)
def nb_write(fd, buf):
"""Write bytes from buffer `buf` to file descriptor `fd`. Return the
number of bytes written.
The file descriptor must be in non-blocking mode.
"""
hub, event = None, None
while True:
try:
return _write(fd, buf)
except OSError, e:
if e.errno not in ignored_errors:
raise
sys.exc_clear()
if hub is None:
hub = get_hub()
event = hub.loop.io(fd, 2)
hub.wait(event)
def tp_read(fd, n):
"""Read up to `n` bytes from file descriptor `fd`. Return a string
containing the bytes read. If end-of-file is reached, an empty string
is returned."""
return get_hub().threadpool.apply_e(BaseException, _read, (fd, n))
def tp_write(fd, buf):
"""Write bytes from buffer `buf` to file descriptor `fd`. Return the
number of bytes written."""
return get_hub().threadpool.apply_e(BaseException, _write, (fd, buf))
if hasattr(os, 'fork'):
_fork = os.fork
def fork():
result = _fork()
if not result:
reinit()
return result
else:
__implements__.remove('fork')
__all__ = __implements__ + __extensions__