michael@0: #!/usr/bin/env python
michael@0: #
michael@0: # Copyright 2011, Google Inc.
michael@0: # All rights reserved.
michael@0: #
michael@0: # Redistribution and use in source and binary forms, with or without
michael@0: # modification, are permitted provided that the following conditions are
michael@0: # met:
michael@0: #
michael@0: #     * Redistributions of source code must retain the above copyright
michael@0: # notice, this list of conditions and the following disclaimer.
michael@0: #     * Redistributions in binary form must reproduce the above
michael@0: # copyright notice, this list of conditions and the following disclaimer
michael@0: # in the documentation and/or other materials provided with the
michael@0: # distribution.
michael@0: #     * Neither the name of Google Inc. nor the names of its
michael@0: # contributors may be used to endorse or promote products derived from
michael@0: # this software without specific prior written permission.
michael@0: #
michael@0: # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
michael@0: # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
michael@0: # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
michael@0: # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
michael@0: # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
michael@0: # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
michael@0: # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
michael@0: # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
michael@0: # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
michael@0: # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
michael@0: # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
michael@0: 
michael@0: 
michael@0: """Memorizing file.
michael@0: 
michael@0: A memorizing file wraps a file and memorizes lines read by readline.
michael@0: """
michael@0: 
michael@0: 
michael@0: import sys
michael@0: 
michael@0: 
michael@0: class MemorizingFile(object):
michael@0:     """MemorizingFile wraps a file and memorizes lines read by readline.
michael@0: 
michael@0:     Note that data read by other methods are not memorized. This behavior
michael@0:     is good enough for memorizing lines SimpleHTTPServer reads before
michael@0:     the control reaches WebSocketRequestHandler.
michael@0:     """
michael@0: 
michael@0:     def __init__(self, file_, max_memorized_lines=sys.maxint):
michael@0:         """Construct an instance.
michael@0: 
michael@0:         Args:
michael@0:             file_: the file object to wrap.
michael@0:             max_memorized_lines: the maximum number of lines to memorize.
michael@0:                 Only the first max_memorized_lines are memorized.
michael@0:                 Default: sys.maxint.
michael@0:         """
michael@0: 
michael@0:         self._file = file_
michael@0:         self._memorized_lines = []
michael@0:         self._max_memorized_lines = max_memorized_lines
michael@0:         self._buffered = False
michael@0:         self._buffered_line = None
michael@0: 
michael@0:     def __getattribute__(self, name):
michael@0:         if name in ('_file', '_memorized_lines', '_max_memorized_lines',
michael@0:                     '_buffered', '_buffered_line', 'readline',
michael@0:                     'get_memorized_lines'):
michael@0:             return object.__getattribute__(self, name)
michael@0:         return self._file.__getattribute__(name)
michael@0: 
michael@0:     def readline(self, size=-1):
michael@0:         """Override file.readline and memorize the line read.
michael@0: 
michael@0:         Note that even if size is specified and smaller than actual size,
michael@0:         the whole line will be read out from underlying file object by
michael@0:         subsequent readline calls.
michael@0:         """
michael@0: 
michael@0:         if self._buffered:
michael@0:             line = self._buffered_line
michael@0:             self._buffered = False
michael@0:         else:
michael@0:             line = self._file.readline()
michael@0:             if line and len(self._memorized_lines) < self._max_memorized_lines:
michael@0:                 self._memorized_lines.append(line)
michael@0:         if size >= 0 and size < len(line):
michael@0:             self._buffered = True
michael@0:             self._buffered_line = line[size:]
michael@0:             return line[:size]
michael@0:         return line
michael@0: 
michael@0:     def get_memorized_lines(self):
michael@0:         """Get lines memorized so far."""
michael@0:         return self._memorized_lines
michael@0: 
michael@0: 
michael@0: # vi:sts=4 sw=4 et