paramiko.pipe

+ 1 # Copyright (C) 2003-2007 Robey Pointer <robey@lag.net> + 2 # + 3 # This file is part of paramiko. + 4 # + 5 # Paramiko is free software; you can redistribute it and/or modify it under the + 6 # terms of the GNU Lesser General Public License as published by the Free + 7 # Software Foundation; either version 2.1 of the License, or (at your option) + 8 # any later version. + 9 # + 10 # Paramiko is distrubuted in the hope that it will be useful, but WITHOUT ANY + 11 # WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR + 12 # A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more + 13 # details. + 14 # + 15 # You should have received a copy of the GNU Lesser General Public License + 16 # along with Paramiko; if not, write to the Free Software Foundation, Inc., + 17 # 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA. + 18 + 19 """ + 20 Abstraction of a one-way pipe where the read end can be used in select(). + 21 Normally this is trivial, but Windows makes it nearly impossible. + 22 + 23 The pipe acts like an Event, which can be set or cleared. When set, the pipe + 24 will trigger as readable in select(). + 25 """ + 26 + 27 import sys + 28 import os + 29 import socket + 30 + 31 +

32 -def make_pipe (): +

33 if sys.platform[:3] != 'win': + 34 p = PosixPipe() + 35 else: + 36 p = WindowsPipe() + 37 return p +

38 + 39 +

40 -class PosixPipe (object): +

41 - def __init__ (self): +

42 self._rfd, self._wfd = os.pipe() + 43 self._set = False + 44 self._forever = False + 45 self._closed = False +

46 +

47 - def close (self): +

48 os.close(self._rfd) + 49 os.close(self._wfd) + 50 # used for unit tests: + 51 self._closed = True +

52 +

53 - def fileno (self): +

54 return self._rfd +

55 +

56 - def clear (self): +

57 if not self._set or self._forever: + 58 return + 59 os.read(self._rfd, 1) + 60 self._set = False +

61 +

62 - def set (self): +

63 if self._set or self._closed: + 64 return + 65 self._set = True + 66 os.write(self._wfd, '*') +

67 +

68 - def set_forever (self): +

69 self._forever = True + 70 self.set() +

71 + 72 +

73 -class WindowsPipe (object): +

74 """ + 75 On Windows, only an OS-level "WinSock" may be used in select(), but reads + 76 and writes must be to the actual socket object. + 77 """ +

78 - def __init__ (self): +

79 serv = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + 80 serv.bind(('127.0.0.1', 0)) + 81 serv.listen(1) + 82 + 83 # need to save sockets in _rsock/_wsock so they don't get closed + 84 self._rsock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + 85 self._rsock.connect(('127.0.0.1', serv.getsockname()[1])) + 86 + 87 self._wsock, addr = serv.accept() + 88 serv.close() + 89 self._set = False + 90 self._forever = False + 91 self._closed = False +

92 +

93 - def close (self): +

94 self._rsock.close() + 95 self._wsock.close() + 96 # used for unit tests: + 97 self._closed = True +

98 +

99 - def fileno (self): +

100 return self._rsock.fileno() +

101 +

102 - def clear (self): +

103 if not self._set or self._forever: +104 return +105 self._rsock.recv(1) +106 self._set = False +

107 +

108 - def set (self): +

109 if self._set or self._closed: +110 return +111 self._set = True +112 self._wsock.send('*') +

113 +

114 - def set_forever (self): +

115 self._forever = True +116 self.set() +

117 +118 +

119 -class OrPipe (object): +

120 - def __init__(self, pipe): +

121 self._set = False +122 self._partner = None +123 self._pipe = pipe +

124 +

125 - def set(self): +

126 self._set = True +127 if not self._partner._set: +128 self._pipe.set() +

129 +

130 - def clear(self): +

131 self._set = False +132 if not self._partner._set: +133 self._pipe.clear() +

134 +135 +

136 -def make_or_pipe(pipe): +

137 """ +138 wraps a pipe into two pipe-like objects which are "or"d together to +139 affect the real pipe. if either returned pipe is set, the wrapped pipe +140 is set. when both are cleared, the wrapped pipe is cleared. +141 """ +142 p1 = OrPipe(pipe) +143 p2 = OrPipe(pipe) +144 p1._partner = p2 +145 p2._partner = p1 +146 return p1, p2 +

147 +

Source Code for Module paramiko.pipe