525 lines
21 KiB
Python
525 lines
21 KiB
Python
from io import StringIO, BytesIO
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import codecs
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import os
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import sys
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import re
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import errno
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from .exceptions import ExceptionPexpect, EOF, TIMEOUT
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from .expect import Expecter, searcher_string, searcher_re
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PY3 = (sys.version_info[0] >= 3)
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text_type = str if PY3 else unicode
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class _NullCoder(object):
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"""Pass bytes through unchanged."""
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@staticmethod
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def encode(b, final=False):
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return b
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@staticmethod
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def decode(b, final=False):
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return b
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class SpawnBase(object):
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"""A base class providing the backwards-compatible spawn API for Pexpect.
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This should not be instantiated directly: use :class:`pexpect.spawn` or
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:class:`pexpect.fdpexpect.fdspawn`.
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"""
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encoding = None
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pid = None
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flag_eof = False
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def __init__(self, timeout=30, maxread=2000, searchwindowsize=None,
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logfile=None, encoding=None, codec_errors='strict'):
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self.stdin = sys.stdin
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self.stdout = sys.stdout
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self.stderr = sys.stderr
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self.searcher = None
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self.ignorecase = False
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self.before = None
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self.after = None
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self.match = None
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self.match_index = None
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self.terminated = True
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self.exitstatus = None
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self.signalstatus = None
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# status returned by os.waitpid
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self.status = None
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# the child file descriptor is initially closed
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self.child_fd = -1
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self.timeout = timeout
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self.delimiter = EOF
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self.logfile = logfile
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# input from child (read_nonblocking)
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self.logfile_read = None
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# output to send (send, sendline)
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self.logfile_send = None
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# max bytes to read at one time into buffer
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self.maxread = maxread
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# Data before searchwindowsize point is preserved, but not searched.
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self.searchwindowsize = searchwindowsize
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# Delay used before sending data to child. Time in seconds.
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# Set this to None to skip the time.sleep() call completely.
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self.delaybeforesend = 0.05
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# Used by close() to give kernel time to update process status.
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# Time in seconds.
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self.delayafterclose = 0.1
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# Used by terminate() to give kernel time to update process status.
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# Time in seconds.
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self.delayafterterminate = 0.1
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# Delay in seconds to sleep after each call to read_nonblocking().
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# Set this to None to skip the time.sleep() call completely: that
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# would restore the behavior from pexpect-2.0 (for performance
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# reasons or because you don't want to release Python's global
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# interpreter lock).
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self.delayafterread = 0.0001
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self.softspace = False
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self.name = '<' + repr(self) + '>'
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self.closed = True
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# Unicode interface
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self.encoding = encoding
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self.codec_errors = codec_errors
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if encoding is None:
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# bytes mode (accepts some unicode for backwards compatibility)
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self._encoder = self._decoder = _NullCoder()
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self.string_type = bytes
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self.buffer_type = BytesIO
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self.crlf = b'\r\n'
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if PY3:
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self.allowed_string_types = (bytes, str)
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self.linesep = os.linesep.encode('ascii')
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def write_to_stdout(b):
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try:
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return sys.stdout.buffer.write(b)
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except AttributeError:
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# If stdout has been replaced, it may not have .buffer
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return sys.stdout.write(b.decode('ascii', 'replace'))
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self.write_to_stdout = write_to_stdout
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else:
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self.allowed_string_types = (basestring,) # analysis:ignore
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self.linesep = os.linesep
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self.write_to_stdout = sys.stdout.write
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else:
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# unicode mode
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self._encoder = codecs.getincrementalencoder(encoding)(codec_errors)
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self._decoder = codecs.getincrementaldecoder(encoding)(codec_errors)
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self.string_type = text_type
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self.buffer_type = StringIO
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self.crlf = u'\r\n'
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self.allowed_string_types = (text_type, )
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if PY3:
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self.linesep = os.linesep
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else:
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self.linesep = os.linesep.decode('ascii')
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# This can handle unicode in both Python 2 and 3
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self.write_to_stdout = sys.stdout.write
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# storage for async transport
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self.async_pw_transport = None
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# This is the read buffer. See maxread.
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self._buffer = self.buffer_type()
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# The buffer may be trimmed for efficiency reasons. This is the
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# untrimmed buffer, used to create the before attribute.
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self._before = self.buffer_type()
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def _log(self, s, direction):
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if self.logfile is not None:
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self.logfile.write(s)
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self.logfile.flush()
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second_log = self.logfile_send if (direction=='send') else self.logfile_read
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if second_log is not None:
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second_log.write(s)
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second_log.flush()
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# For backwards compatibility, in bytes mode (when encoding is None)
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# unicode is accepted for send and expect. Unicode mode is strictly unicode
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# only.
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def _coerce_expect_string(self, s):
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if self.encoding is None and not isinstance(s, bytes):
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return s.encode('ascii')
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return s
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def _coerce_send_string(self, s):
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if self.encoding is None and not isinstance(s, bytes):
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return s.encode('utf-8')
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return s
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def _get_buffer(self):
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return self._buffer.getvalue()
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def _set_buffer(self, value):
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self._buffer = self.buffer_type()
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self._buffer.write(value)
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# This property is provided for backwards compatability (self.buffer used
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# to be a string/bytes object)
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buffer = property(_get_buffer, _set_buffer)
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def read_nonblocking(self, size=1, timeout=None):
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"""This reads data from the file descriptor.
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This is a simple implementation suitable for a regular file. Subclasses using ptys or pipes should override it.
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The timeout parameter is ignored.
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"""
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try:
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s = os.read(self.child_fd, size)
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except OSError as err:
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if err.args[0] == errno.EIO:
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# Linux-style EOF
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self.flag_eof = True
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raise EOF('End Of File (EOF). Exception style platform.')
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raise
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if s == b'':
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# BSD-style EOF
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self.flag_eof = True
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raise EOF('End Of File (EOF). Empty string style platform.')
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s = self._decoder.decode(s, final=False)
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self._log(s, 'read')
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return s
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def _pattern_type_err(self, pattern):
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raise TypeError('got {badtype} ({badobj!r}) as pattern, must be one'
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' of: {goodtypes}, pexpect.EOF, pexpect.TIMEOUT'\
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.format(badtype=type(pattern),
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badobj=pattern,
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goodtypes=', '.join([str(ast)\
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for ast in self.allowed_string_types])
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)
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)
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def compile_pattern_list(self, patterns):
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'''This compiles a pattern-string or a list of pattern-strings.
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Patterns must be a StringType, EOF, TIMEOUT, SRE_Pattern, or a list of
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those. Patterns may also be None which results in an empty list (you
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might do this if waiting for an EOF or TIMEOUT condition without
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expecting any pattern).
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This is used by expect() when calling expect_list(). Thus expect() is
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nothing more than::
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cpl = self.compile_pattern_list(pl)
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return self.expect_list(cpl, timeout)
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If you are using expect() within a loop it may be more
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efficient to compile the patterns first and then call expect_list().
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This avoid calls in a loop to compile_pattern_list()::
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cpl = self.compile_pattern_list(my_pattern)
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while some_condition:
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...
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i = self.expect_list(cpl, timeout)
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...
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'''
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if patterns is None:
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return []
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if not isinstance(patterns, list):
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patterns = [patterns]
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# Allow dot to match \n
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compile_flags = re.DOTALL
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if self.ignorecase:
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compile_flags = compile_flags | re.IGNORECASE
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compiled_pattern_list = []
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for idx, p in enumerate(patterns):
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if isinstance(p, self.allowed_string_types):
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p = self._coerce_expect_string(p)
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compiled_pattern_list.append(re.compile(p, compile_flags))
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elif p is EOF:
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compiled_pattern_list.append(EOF)
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elif p is TIMEOUT:
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compiled_pattern_list.append(TIMEOUT)
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elif isinstance(p, type(re.compile(''))):
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compiled_pattern_list.append(p)
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else:
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self._pattern_type_err(p)
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return compiled_pattern_list
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def expect(self, pattern, timeout=-1, searchwindowsize=-1, async_=False, **kw):
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'''This seeks through the stream until a pattern is matched. The
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pattern is overloaded and may take several types. The pattern can be a
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StringType, EOF, a compiled re, or a list of any of those types.
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Strings will be compiled to re types. This returns the index into the
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pattern list. If the pattern was not a list this returns index 0 on a
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successful match. This may raise exceptions for EOF or TIMEOUT. To
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avoid the EOF or TIMEOUT exceptions add EOF or TIMEOUT to the pattern
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list. That will cause expect to match an EOF or TIMEOUT condition
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instead of raising an exception.
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If you pass a list of patterns and more than one matches, the first
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match in the stream is chosen. If more than one pattern matches at that
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point, the leftmost in the pattern list is chosen. For example::
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# the input is 'foobar'
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index = p.expect(['bar', 'foo', 'foobar'])
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# returns 1('foo') even though 'foobar' is a "better" match
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Please note, however, that buffering can affect this behavior, since
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input arrives in unpredictable chunks. For example::
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# the input is 'foobar'
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index = p.expect(['foobar', 'foo'])
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# returns 0('foobar') if all input is available at once,
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# but returns 1('foo') if parts of the final 'bar' arrive late
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When a match is found for the given pattern, the class instance
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attribute *match* becomes an re.MatchObject result. Should an EOF
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or TIMEOUT pattern match, then the match attribute will be an instance
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of that exception class. The pairing before and after class
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instance attributes are views of the data preceding and following
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the matching pattern. On general exception, class attribute
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*before* is all data received up to the exception, while *match* and
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*after* attributes are value None.
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When the keyword argument timeout is -1 (default), then TIMEOUT will
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raise after the default value specified by the class timeout
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attribute. When None, TIMEOUT will not be raised and may block
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indefinitely until match.
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When the keyword argument searchwindowsize is -1 (default), then the
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value specified by the class maxread attribute is used.
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A list entry may be EOF or TIMEOUT instead of a string. This will
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catch these exceptions and return the index of the list entry instead
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of raising the exception. The attribute 'after' will be set to the
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exception type. The attribute 'match' will be None. This allows you to
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write code like this::
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index = p.expect(['good', 'bad', pexpect.EOF, pexpect.TIMEOUT])
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if index == 0:
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do_something()
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elif index == 1:
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do_something_else()
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elif index == 2:
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do_some_other_thing()
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elif index == 3:
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do_something_completely_different()
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instead of code like this::
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try:
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index = p.expect(['good', 'bad'])
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if index == 0:
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do_something()
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elif index == 1:
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do_something_else()
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except EOF:
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do_some_other_thing()
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except TIMEOUT:
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do_something_completely_different()
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These two forms are equivalent. It all depends on what you want. You
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can also just expect the EOF if you are waiting for all output of a
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child to finish. For example::
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p = pexpect.spawn('/bin/ls')
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p.expect(pexpect.EOF)
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print p.before
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If you are trying to optimize for speed then see expect_list().
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On Python 3.4, or Python 3.3 with asyncio installed, passing
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``async_=True`` will make this return an :mod:`asyncio` coroutine,
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which you can yield from to get the same result that this method would
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normally give directly. So, inside a coroutine, you can replace this code::
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index = p.expect(patterns)
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With this non-blocking form::
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index = yield from p.expect(patterns, async_=True)
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'''
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if 'async' in kw:
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async_ = kw.pop('async')
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if kw:
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raise TypeError("Unknown keyword arguments: {}".format(kw))
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compiled_pattern_list = self.compile_pattern_list(pattern)
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return self.expect_list(compiled_pattern_list,
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timeout, searchwindowsize, async_)
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def expect_list(self, pattern_list, timeout=-1, searchwindowsize=-1,
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async_=False, **kw):
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'''This takes a list of compiled regular expressions and returns the
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index into the pattern_list that matched the child output. The list may
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also contain EOF or TIMEOUT(which are not compiled regular
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expressions). This method is similar to the expect() method except that
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expect_list() does not recompile the pattern list on every call. This
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may help if you are trying to optimize for speed, otherwise just use
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the expect() method. This is called by expect().
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Like :meth:`expect`, passing ``async_=True`` will make this return an
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asyncio coroutine.
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'''
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if timeout == -1:
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timeout = self.timeout
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if 'async' in kw:
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async_ = kw.pop('async')
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if kw:
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raise TypeError("Unknown keyword arguments: {}".format(kw))
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exp = Expecter(self, searcher_re(pattern_list), searchwindowsize)
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if async_:
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from ._async import expect_async
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return expect_async(exp, timeout)
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else:
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return exp.expect_loop(timeout)
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def expect_exact(self, pattern_list, timeout=-1, searchwindowsize=-1,
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async_=False, **kw):
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'''This is similar to expect(), but uses plain string matching instead
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of compiled regular expressions in 'pattern_list'. The 'pattern_list'
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may be a string; a list or other sequence of strings; or TIMEOUT and
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EOF.
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This call might be faster than expect() for two reasons: string
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searching is faster than RE matching and it is possible to limit the
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search to just the end of the input buffer.
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This method is also useful when you don't want to have to worry about
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escaping regular expression characters that you want to match.
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Like :meth:`expect`, passing ``async_=True`` will make this return an
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asyncio coroutine.
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'''
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if timeout == -1:
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timeout = self.timeout
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if 'async' in kw:
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async_ = kw.pop('async')
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if kw:
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raise TypeError("Unknown keyword arguments: {}".format(kw))
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if (isinstance(pattern_list, self.allowed_string_types) or
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pattern_list in (TIMEOUT, EOF)):
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pattern_list = [pattern_list]
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def prepare_pattern(pattern):
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if pattern in (TIMEOUT, EOF):
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return pattern
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if isinstance(pattern, self.allowed_string_types):
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return self._coerce_expect_string(pattern)
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self._pattern_type_err(pattern)
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try:
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pattern_list = iter(pattern_list)
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except TypeError:
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self._pattern_type_err(pattern_list)
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pattern_list = [prepare_pattern(p) for p in pattern_list]
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exp = Expecter(self, searcher_string(pattern_list), searchwindowsize)
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if async_:
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from ._async import expect_async
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return expect_async(exp, timeout)
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else:
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return exp.expect_loop(timeout)
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def expect_loop(self, searcher, timeout=-1, searchwindowsize=-1):
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'''This is the common loop used inside expect. The 'searcher' should be
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an instance of searcher_re or searcher_string, which describes how and
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what to search for in the input.
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See expect() for other arguments, return value and exceptions. '''
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exp = Expecter(self, searcher, searchwindowsize)
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return exp.expect_loop(timeout)
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def read(self, size=-1):
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'''This reads at most "size" bytes from the file (less if the read hits
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EOF before obtaining size bytes). If the size argument is negative or
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omitted, read all data until EOF is reached. The bytes are returned as
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a string object. An empty string is returned when EOF is encountered
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immediately. '''
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if size == 0:
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return self.string_type()
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if size < 0:
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# delimiter default is EOF
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self.expect(self.delimiter)
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return self.before
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# I could have done this more directly by not using expect(), but
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# I deliberately decided to couple read() to expect() so that
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# I would catch any bugs early and ensure consistent behavior.
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# It's a little less efficient, but there is less for me to
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# worry about if I have to later modify read() or expect().
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# Note, it's OK if size==-1 in the regex. That just means it
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# will never match anything in which case we stop only on EOF.
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cre = re.compile(self._coerce_expect_string('.{%d}' % size), re.DOTALL)
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# delimiter default is EOF
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index = self.expect([cre, self.delimiter])
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if index == 0:
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### FIXME self.before should be ''. Should I assert this?
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return self.after
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return self.before
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def readline(self, size=-1):
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'''This reads and returns one entire line. The newline at the end of
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line is returned as part of the string, unless the file ends without a
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newline. An empty string is returned if EOF is encountered immediately.
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This looks for a newline as a CR/LF pair (\\r\\n) even on UNIX because
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this is what the pseudotty device returns. So contrary to what you may
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expect you will receive newlines as \\r\\n.
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If the size argument is 0 then an empty string is returned. In all
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other cases the size argument is ignored, which is not standard
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behavior for a file-like object. '''
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if size == 0:
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return self.string_type()
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# delimiter default is EOF
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index = self.expect([self.crlf, self.delimiter])
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if index == 0:
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return self.before + self.crlf
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else:
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return self.before
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def __iter__(self):
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'''This is to support iterators over a file-like object.
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'''
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return iter(self.readline, self.string_type())
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def readlines(self, sizehint=-1):
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'''This reads until EOF using readline() and returns a list containing
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the lines thus read. The optional 'sizehint' argument is ignored.
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Remember, because this reads until EOF that means the child
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process should have closed its stdout. If you run this method on
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a child that is still running with its stdout open then this
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method will block until it timesout.'''
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lines = []
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while True:
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line = self.readline()
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if not line:
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break
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lines.append(line)
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|
return lines
|
|
|
|
def fileno(self):
|
|
'''Expose file descriptor for a file-like interface
|
|
'''
|
|
return self.child_fd
|
|
|
|
def flush(self):
|
|
'''This does nothing. It is here to support the interface for a
|
|
File-like object. '''
|
|
pass
|
|
|
|
def isatty(self):
|
|
"""Overridden in subclass using tty"""
|
|
return False
|
|
|
|
# For 'with spawn(...) as child:'
|
|
def __enter__(self):
|
|
return self
|
|
|
|
def __exit__(self, etype, evalue, tb):
|
|
# We rely on subclasses to implement close(). If they don't, it's not
|
|
# clear what a context manager should do.
|
|
self.close()
|