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# I/O
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import timeouts
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##### Exceptions
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class InputStreamsOnlyException(Exception):
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def __init__(self): Exception.__init__(self, 'Only input streams allowed')
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##### Wrapped streams
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class WrapStream:
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'''Forwards close() to the underlying stream'''
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def __init__(self, stream): self.stream = stream
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def close(self): self.stream.close()
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##### Line iteration
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class StreamIter(WrapStream):
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'''Iterates over the lines in a stream.
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Unlike stream.__iter__(), doesn't wait for EOF to start returning lines.
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Offers curr() method.
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'''
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def __init__(self, stream):
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WrapStream.__init__(self, stream)
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self.line = None
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def __iter__(self): return self
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def curr(self):
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if self.line == None: self.line = self.stream.readline()
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if self.line == '': raise StopIteration
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return self.line
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def next(self):
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line = self.curr()
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self.line = None
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return line
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def copy(from_, to):
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for line in StreamIter(from_): to.write(line)
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def consume(in_):
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for line in StreamIter(in_): pass
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##### Timeouts
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class TimeoutInputStream(WrapStream):
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'''@param timeout sec'''
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def __init__(self, stream, timeout):
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WrapStream.__init__(self, stream)
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self.timeout = timeout
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def readline(self):
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return timeouts.run(lambda: self.stream.readline(), self.timeout)
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def write(self, str_): raise InputStreamsOnlyException()
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##### Filtered/traced streams
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class FilterStream(WrapStream):
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'''Wraps a stream, filtering each string read or written'''
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def __init__(self, filter_, stream):
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WrapStream.__init__(self, stream)
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self.filter = filter_
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def readline(self): return self.filter(self.stream.readline())
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def read(self, n): return self.readline() # forward all reads to readline()
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def write(self, str_): return self.stream.write(self.filter(str_))
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class TracedStream(FilterStream):
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'''Wraps a stream, running a trace function on each string read or written
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'''
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def __init__(self, trace, stream):
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def filter_(str_):
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trace(str_)
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return str_
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FilterStream.__init__(self, filter_, stream)
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class LineCountStream(TracedStream):
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'''Wraps a unidirectional stream, making the current line number available.
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Lines start counting from 1.'''
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def __init__(self, stream):
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self.line_num = 1
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def trace(str_): self.line_num += str_.count('\n')
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TracedStream.__init__(self, trace, stream)
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class LineCountInputStream(TracedStream):
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'''Wraps an input stream, making the current line number available.
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Lines start counting from 1.
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This is faster than LineCountStream for input streams, because all reading
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is done through readline() so newlines don't need to be explicitly counted.
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'''
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def __init__(self, stream):
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self.line_num = 1
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def trace(str_): self.line_num += 1
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TracedStream.__init__(self, trace, stream)
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def write(self, str_): raise InputStreamsOnlyException()
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class ProgressInputStream(TracedStream):
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'''Wraps an input stream, reporting the # lines read every n lines and after
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the last line is read.
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@param log The output stream for progress messages
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'''
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def __init__(self, stream, log, msg='Read %d line(s)', n=100):
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self.eof = False
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def trace(str_):
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msg_ = msg # may be modified, so can't have same name as outer var
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if str_ == None: # closed
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if self.eof: return # not closed prematurely
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str_ = '' # closed prematurely, so signal EOF
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msg_ += ' (not all input read)'
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self.eof = eof = str_ == ''
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if eof: line_ending = '\n'
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else: line_ending = '\r'
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line_ct = self.stream.line_num - 1 # make it 0-based
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if eof or line_ct % n == 0: log.write((msg_ % line_ct)+line_ending)
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self.trace = trace
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TracedStream.__init__(self, trace, LineCountInputStream(stream))
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def close(self):
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self.trace(None) # signal closed
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TracedStream.close(self)
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class CaptureStream(TracedStream):
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'''Wraps a stream, capturing matching text.
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Matches can be retrieved from self.matches.'''
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def __init__(self, stream, start_str, end_str):
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self.recording = False
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self.matches = []
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def trace(str_):
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start_idx = 0
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if not self.recording:
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start_idx = str_.find(start_str)
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if start_idx >= 0:
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self.recording = True
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self.matches.append('')
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if self.recording:
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end_idx = str_.find(end_str)
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if end_idx >= 0:
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self.recording = False
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end_idx += len(end_str)
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else: end_idx = len(str_)
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self.matches[-1] += str_[start_idx:end_idx]
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TracedStream.__init__(self, trace, stream)
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