mirror of https://github.com/ArduPilot/ardupilot
84 lines
2.5 KiB
Python
84 lines
2.5 KiB
Python
"""This is like pexpect, but will work on any file descriptor that you pass it.
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So you are responsible for opening and close the file descriptor.
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$Id: fdpexpect.py 505 2007-12-26 21:33:50Z noah $
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"""
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from __future__ import print_function
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import os
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from pexpect import ExceptionPexpect, spawn
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__all__ = ['fdspawn']
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class fdspawn(spawn):
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"""This is like pexpect.spawn but allows you to supply your own open file
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descriptor. For example, you could use it to read through a file looking
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for patterns, or to control a modem or serial device. """
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def __init__(self, fd, args=[], timeout=30, maxread=2000, searchwindowsize=None, logfile=None):
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"""This takes a file descriptor (an int) or an object that support the
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fileno() method (returning an int). All Python file-like objects
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support fileno(). """
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# TODO: Add better handling of trying to use fdspawn in place of spawn
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# TODO: (overload to allow fdspawn to also handle commands as spawn does.
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if not isinstance(fd, int) and hasattr(fd, 'fileno'):
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fd = fd.fileno()
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if not isinstance(fd, int):
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raise ExceptionPexpect(
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"The fd argument is not an int. If this is a command string then maybe you want to use pexpect.spawn.")
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try: # make sure fd is a valid file descriptor
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os.fstat(fd)
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except OSError:
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raise ExceptionPexpect("The fd argument is not a valid file descriptor.")
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self.args = None
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self.command = None
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spawn.__init__(self, None, args, timeout, maxread, searchwindowsize, logfile)
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self.child_fd = fd
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self.own_fd = False
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self.closed = False
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self.name = '<file descriptor %d>' % fd
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def __del__(self):
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return
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def close(self):
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if self.child_fd == -1:
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return
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if self.own_fd:
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self.close(self)
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else:
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self.flush()
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os.close(self.child_fd)
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self.child_fd = -1
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self.closed = True
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def isalive(self):
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"""This checks if the file descriptor is still valid. If os.fstat()
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does not raise an exception then we assume it is alive. """
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if self.child_fd == -1:
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return False
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try:
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os.fstat(self.child_fd)
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return True
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except:
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return False
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def terminate(self, force=False):
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raise ExceptionPexpect('This method is not valid for file descriptors.')
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def kill(self, sig):
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return
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