third_party/pexpect/fdpexpect.py

   1 """This is like pexpect, but will work on any file descriptor that you pass it.
   2 You are reponsible for opening and close the file descriptor.
   3
   4 PEXPECT LICENSE
   5
   6     This license is approved by the OSI and FSF as GPL-compatible.
   7         http://opensource.org/licenses/isc-license.txt
   8
   9     Copyright (c) 2012, Noah Spurrier <noah@noah.org>
  10     PERMISSION TO USE, COPY, MODIFY, AND/OR DISTRIBUTE THIS SOFTWARE FOR ANY
  11     PURPOSE WITH OR WITHOUT FEE IS HEREBY GRANTED, PROVIDED THAT THE ABOVE
  12     COPYRIGHT NOTICE AND THIS PERMISSION NOTICE APPEAR IN ALL COPIES.
  13     THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  14     WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  15     MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  16     ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  17     WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  18     ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  19     OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  20
  21 """
  22
  23 from pexpect import *
  24 import os
  25
  26 __all__ = ['fdspawn']
  27
  28 class fdspawn (spawn):
  29
  30     """This is like pexpect.spawn but allows you to supply your own open file
  31     descriptor. For example, you could use it to read through a file looking
  32     for patterns, or to control a modem or serial device. """
  33
  34     def __init__ (self, fd, args=[], timeout=30, maxread=2000, searchwindowsize=None, logfile=None):
  35
  36         """This takes a file descriptor (an int) or an object that support the
  37         fileno() method (returning an int). All Python file-like objects
  38         support fileno(). """
  39
  40         ### TODO: Add better handling of trying to use fdspawn in place of spawn
  41         ### TODO: (overload to allow fdspawn to also handle commands as spawn does.
  42
  43         if type(fd) != type(0) and hasattr(fd, 'fileno'):
  44             fd = fd.fileno()
  45
  46         if type(fd) != type(0):
  47             raise ExceptionPexpect ('The fd argument is not an int. If this is a command string then maybe you want to use pexpect.spawn.')
  48
  49         try: # make sure fd is a valid file descriptor
  50             os.fstat(fd)
  51         except OSError:
  52             raise ExceptionPexpect, 'The fd argument is not a valid file descriptor.'
  53
  54         self.args = None
  55         self.command = None
  56         spawn.__init__(self, None, args, timeout, maxread, searchwindowsize, logfile)
  57         self.child_fd = fd
  58         self.own_fd = False
  59         self.closed = False
  60         self.name = '<file descriptor %d>' % fd
  61
  62     def __del__ (self):
  63
  64         return
  65
  66     def close (self):
  67
  68         if self.child_fd == -1:
  69             return
  70         if self.own_fd:
  71             self.close (self)
  72         else:
  73             self.flush()
  74             os.close(self.child_fd)
  75             self.child_fd = -1
  76             self.closed = True
  77
  78     def isalive (self):
  79
  80         """This checks if the file descriptor is still valid. If os.fstat()
  81         does not raise an exception then we assume it is alive. """
  82
  83         if self.child_fd == -1:
  84             return False
  85         try:
  86             os.fstat(self.child_fd)
  87             return True
  88         except:
  89             return False
  90
  91     def terminate (self, force=False):
  92
  93         raise ExceptionPexpect ('This method is not valid for file descriptors.')
  94
  95     def kill (self, sig):
  96
  97         return
  98