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- # Copyright (C) 2003-2007 Robey Pointer <robeypointer@gmail.com>
- #
- # This file is part of paramiko.
- #
- # Paramiko is free software; you can redistribute it and/or modify it under the
- # terms of the GNU Lesser General Public License as published by the Free
- # Software Foundation; either version 2.1 of the License, or (at your option)
- # any later version.
- #
- # Paramiko is distributed in the hope that it will be useful, but WITHOUT ANY
- # WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
- # A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
- # details.
- #
- # You should have received a copy of the GNU Lesser General Public License
- # along with Paramiko; if not, write to the Free Software Foundation, Inc.,
- # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
- """
- Abstraction of a one-way pipe where the read end can be used in
- `select.select`. Normally this is trivial, but Windows makes it nearly
- impossible.
- The pipe acts like an Event, which can be set or cleared. When set, the pipe
- will trigger as readable in `select <select.select>`.
- """
- import sys
- import os
- import socket
- def make_pipe():
- if sys.platform[:3] != "win":
- p = PosixPipe()
- else:
- p = WindowsPipe()
- return p
- class PosixPipe(object):
- def __init__(self):
- self._rfd, self._wfd = os.pipe()
- self._set = False
- self._forever = False
- self._closed = False
- def close(self):
- os.close(self._rfd)
- os.close(self._wfd)
- # used for unit tests:
- self._closed = True
- def fileno(self):
- return self._rfd
- def clear(self):
- if not self._set or self._forever:
- return
- os.read(self._rfd, 1)
- self._set = False
- def set(self):
- if self._set or self._closed:
- return
- self._set = True
- os.write(self._wfd, b"*")
- def set_forever(self):
- self._forever = True
- self.set()
- class WindowsPipe(object):
- """
- On Windows, only an OS-level "WinSock" may be used in select(), but reads
- and writes must be to the actual socket object.
- """
- def __init__(self):
- serv = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
- serv.bind(("127.0.0.1", 0))
- serv.listen(1)
- # need to save sockets in _rsock/_wsock so they don't get closed
- self._rsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
- self._rsock.connect(("127.0.0.1", serv.getsockname()[1]))
- self._wsock, addr = serv.accept()
- serv.close()
- self._set = False
- self._forever = False
- self._closed = False
- def close(self):
- self._rsock.close()
- self._wsock.close()
- # used for unit tests:
- self._closed = True
- def fileno(self):
- return self._rsock.fileno()
- def clear(self):
- if not self._set or self._forever:
- return
- self._rsock.recv(1)
- self._set = False
- def set(self):
- if self._set or self._closed:
- return
- self._set = True
- self._wsock.send(b"*")
- def set_forever(self):
- self._forever = True
- self.set()
- class OrPipe(object):
- def __init__(self, pipe):
- self._set = False
- self._partner = None
- self._pipe = pipe
- def set(self):
- self._set = True
- if not self._partner._set:
- self._pipe.set()
- def clear(self):
- self._set = False
- if not self._partner._set:
- self._pipe.clear()
- def make_or_pipe(pipe):
- """
- wraps a pipe into two pipe-like objects which are "or"d together to
- affect the real pipe. if either returned pipe is set, the wrapped pipe
- is set. when both are cleared, the wrapped pipe is cleared.
- """
- p1 = OrPipe(pipe)
- p2 = OrPipe(pipe)
- p1._partner = p2
- p2._partner = p1
- return p1, p2
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