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- import time
-
- from .exceptions import EOF, TIMEOUT
-
- class Expecter(object):
- def __init__(self, spawn, searcher, searchwindowsize=-1):
- self.spawn = spawn
- self.searcher = searcher
- if searchwindowsize == -1:
- searchwindowsize = spawn.searchwindowsize
- self.searchwindowsize = searchwindowsize
-
- def new_data(self, data):
- spawn = self.spawn
- searcher = self.searcher
-
- pos = spawn._buffer.tell()
- spawn._buffer.write(data)
- spawn._before.write(data)
-
- # determine which chunk of data to search; if a windowsize is
- # specified, this is the *new* data + the preceding <windowsize> bytes
- if self.searchwindowsize:
- spawn._buffer.seek(max(0, pos - self.searchwindowsize))
- window = spawn._buffer.read(self.searchwindowsize + len(data))
- else:
- # otherwise, search the whole buffer (really slow for large datasets)
- window = spawn.buffer
- index = searcher.search(window, len(data))
- if index >= 0:
- spawn._buffer = spawn.buffer_type()
- spawn._buffer.write(window[searcher.end:])
- spawn.before = spawn._before.getvalue()[0:-(len(window) - searcher.start)]
- spawn._before = spawn.buffer_type()
- spawn.after = window[searcher.start: searcher.end]
- spawn.match = searcher.match
- spawn.match_index = index
- # Found a match
- return index
- elif self.searchwindowsize:
- spawn._buffer = spawn.buffer_type()
- spawn._buffer.write(window)
-
- def eof(self, err=None):
- spawn = self.spawn
-
- spawn.before = spawn.buffer
- spawn._buffer = spawn.buffer_type()
- spawn._before = spawn.buffer_type()
- spawn.after = EOF
- index = self.searcher.eof_index
- if index >= 0:
- spawn.match = EOF
- spawn.match_index = index
- return index
- else:
- spawn.match = None
- spawn.match_index = None
- msg = str(spawn)
- msg += '\nsearcher: %s' % self.searcher
- if err is not None:
- msg = str(err) + '\n' + msg
- raise EOF(msg)
-
- def timeout(self, err=None):
- spawn = self.spawn
-
- spawn.before = spawn.buffer
- spawn.after = TIMEOUT
- index = self.searcher.timeout_index
- if index >= 0:
- spawn.match = TIMEOUT
- spawn.match_index = index
- return index
- else:
- spawn.match = None
- spawn.match_index = None
- msg = str(spawn)
- msg += '\nsearcher: %s' % self.searcher
- if err is not None:
- msg = str(err) + '\n' + msg
- raise TIMEOUT(msg)
-
- def errored(self):
- spawn = self.spawn
- spawn.before = spawn.buffer
- spawn.after = None
- spawn.match = None
- spawn.match_index = None
-
- def expect_loop(self, timeout=-1):
- """Blocking expect"""
- spawn = self.spawn
-
- if timeout is not None:
- end_time = time.time() + timeout
-
- try:
- incoming = spawn.buffer
- spawn._buffer = spawn.buffer_type()
- spawn._before = spawn.buffer_type()
- while True:
- idx = self.new_data(incoming)
- # Keep reading until exception or return.
- if idx is not None:
- return idx
- # No match at this point
- if (timeout is not None) and (timeout < 0):
- return self.timeout()
- # Still have time left, so read more data
- incoming = spawn.read_nonblocking(spawn.maxread, timeout)
- if self.spawn.delayafterread is not None:
- time.sleep(self.spawn.delayafterread)
- if timeout is not None:
- timeout = end_time - time.time()
- except EOF as e:
- return self.eof(e)
- except TIMEOUT as e:
- return self.timeout(e)
- except:
- self.errored()
- raise
-
-
- class searcher_string(object):
- '''This is a plain string search helper for the spawn.expect_any() method.
- This helper class is for speed. For more powerful regex patterns
- see the helper class, searcher_re.
-
- Attributes:
-
- eof_index - index of EOF, or -1
- timeout_index - index of TIMEOUT, or -1
-
- After a successful match by the search() method the following attributes
- are available:
-
- start - index into the buffer, first byte of match
- end - index into the buffer, first byte after match
- match - the matching string itself
-
- '''
-
- def __init__(self, strings):
- '''This creates an instance of searcher_string. This argument 'strings'
- may be a list; a sequence of strings; or the EOF or TIMEOUT types. '''
-
- self.eof_index = -1
- self.timeout_index = -1
- self._strings = []
- for n, s in enumerate(strings):
- if s is EOF:
- self.eof_index = n
- continue
- if s is TIMEOUT:
- self.timeout_index = n
- continue
- self._strings.append((n, s))
-
- def __str__(self):
- '''This returns a human-readable string that represents the state of
- the object.'''
-
- ss = [(ns[0], ' %d: %r' % ns) for ns in self._strings]
- ss.append((-1, 'searcher_string:'))
- if self.eof_index >= 0:
- ss.append((self.eof_index, ' %d: EOF' % self.eof_index))
- if self.timeout_index >= 0:
- ss.append((self.timeout_index,
- ' %d: TIMEOUT' % self.timeout_index))
- ss.sort()
- ss = list(zip(*ss))[1]
- return '\n'.join(ss)
-
- def search(self, buffer, freshlen, searchwindowsize=None):
- '''This searches 'buffer' for the first occurrence of one of the search
- strings. 'freshlen' must indicate the number of bytes at the end of
- 'buffer' which have not been searched before. It helps to avoid
- searching the same, possibly big, buffer over and over again.
-
- See class spawn for the 'searchwindowsize' argument.
-
- If there is a match this returns the index of that string, and sets
- 'start', 'end' and 'match'. Otherwise, this returns -1. '''
-
- first_match = None
-
- # 'freshlen' helps a lot here. Further optimizations could
- # possibly include:
- #
- # using something like the Boyer-Moore Fast String Searching
- # Algorithm; pre-compiling the search through a list of
- # strings into something that can scan the input once to
- # search for all N strings; realize that if we search for
- # ['bar', 'baz'] and the input is '...foo' we need not bother
- # rescanning until we've read three more bytes.
- #
- # Sadly, I don't know enough about this interesting topic. /grahn
-
- for index, s in self._strings:
- if searchwindowsize is None:
- # the match, if any, can only be in the fresh data,
- # or at the very end of the old data
- offset = -(freshlen + len(s))
- else:
- # better obey searchwindowsize
- offset = -searchwindowsize
- n = buffer.find(s, offset)
- if n >= 0 and (first_match is None or n < first_match):
- first_match = n
- best_index, best_match = index, s
- if first_match is None:
- return -1
- self.match = best_match
- self.start = first_match
- self.end = self.start + len(self.match)
- return best_index
-
-
- class searcher_re(object):
- '''This is regular expression string search helper for the
- spawn.expect_any() method. This helper class is for powerful
- pattern matching. For speed, see the helper class, searcher_string.
-
- Attributes:
-
- eof_index - index of EOF, or -1
- timeout_index - index of TIMEOUT, or -1
-
- After a successful match by the search() method the following attributes
- are available:
-
- start - index into the buffer, first byte of match
- end - index into the buffer, first byte after match
- match - the re.match object returned by a successful re.search
-
- '''
-
- def __init__(self, patterns):
- '''This creates an instance that searches for 'patterns' Where
- 'patterns' may be a list or other sequence of compiled regular
- expressions, or the EOF or TIMEOUT types.'''
-
- self.eof_index = -1
- self.timeout_index = -1
- self._searches = []
- for n, s in zip(list(range(len(patterns))), patterns):
- if s is EOF:
- self.eof_index = n
- continue
- if s is TIMEOUT:
- self.timeout_index = n
- continue
- self._searches.append((n, s))
-
- def __str__(self):
- '''This returns a human-readable string that represents the state of
- the object.'''
-
- #ss = [(n, ' %d: re.compile("%s")' %
- # (n, repr(s.pattern))) for n, s in self._searches]
- ss = list()
- for n, s in self._searches:
- ss.append((n, ' %d: re.compile(%r)' % (n, s.pattern)))
- ss.append((-1, 'searcher_re:'))
- if self.eof_index >= 0:
- ss.append((self.eof_index, ' %d: EOF' % self.eof_index))
- if self.timeout_index >= 0:
- ss.append((self.timeout_index, ' %d: TIMEOUT' %
- self.timeout_index))
- ss.sort()
- ss = list(zip(*ss))[1]
- return '\n'.join(ss)
-
- def search(self, buffer, freshlen, searchwindowsize=None):
- '''This searches 'buffer' for the first occurrence of one of the regular
- expressions. 'freshlen' must indicate the number of bytes at the end of
- 'buffer' which have not been searched before.
-
- See class spawn for the 'searchwindowsize' argument.
-
- If there is a match this returns the index of that string, and sets
- 'start', 'end' and 'match'. Otherwise, returns -1.'''
-
- first_match = None
- # 'freshlen' doesn't help here -- we cannot predict the
- # length of a match, and the re module provides no help.
- if searchwindowsize is None:
- searchstart = 0
- else:
- searchstart = max(0, len(buffer) - searchwindowsize)
- for index, s in self._searches:
- match = s.search(buffer, searchstart)
- if match is None:
- continue
- n = match.start()
- if first_match is None or n < first_match:
- first_match = n
- the_match = match
- best_index = index
- if first_match is None:
- return -1
- self.start = first_match
- self.match = the_match
- self.end = self.match.end()
- return best_index
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