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1#!/usr/bin/env python
2#
3# Copyright 2009, Google Inc.
4# All rights reserved.
5#
6# Redistribution and use in source and binary forms, with or without
7# modification, are permitted provided that the following conditions are
8# met:
9#
10#     * Redistributions of source code must retain the above copyright
11# notice, this list of conditions and the following disclaimer.
12#     * Redistributions in binary form must reproduce the above
13# copyright notice, this list of conditions and the following disclaimer
14# in the documentation and/or other materials provided with the
15# distribution.
16#     * Neither the name of Google Inc. nor the names of its
17# contributors may be used to endorse or promote products derived from
18# this software without specific prior written permission.
19#
20# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
21# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
22# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
23# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
24# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
25# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
26# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
30# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31
32
33"""Memorizing file.
34
35A memorizing file wraps a file and memorizes lines read by readline.
36"""
37
38
39import sys
40
41
42class MemorizingFile(object):
43    """MemorizingFile wraps a file and memorizes lines read by readline.
44
45    Note that data read by other methods are not memorized. This behavior
46    is good enough for memorizing lines SimpleHTTPServer reads before
47    the control reaches WebSocketRequestHandler.
48    """
49    def __init__(self, file_, max_memorized_lines=sys.maxint):
50        """Construct an instance.
51
52        Args:
53            file_: the file object to wrap.
54            max_memorized_lines: the maximum number of lines to memorize.
55                Only the first max_memorized_lines are memorized.
56                Default: sys.maxint.
57        """
58        self._file = file_
59        self._memorized_lines = []
60        self._max_memorized_lines = max_memorized_lines
61
62    def __getattribute__(self, name):
63        if name in ('_file', '_memorized_lines', '_max_memorized_lines',
64                    'readline', 'get_memorized_lines'):
65            return object.__getattribute__(self, name)
66        return self._file.__getattribute__(name)
67
68    def readline(self):
69        """Override file.readline and memorize the line read."""
70
71        line = self._file.readline()
72        if line and len(self._memorized_lines) < self._max_memorized_lines:
73            self._memorized_lines.append(line)
74        return line
75
76    def get_memorized_lines(self):
77        """Get lines memorized so far."""
78        return self._memorized_lines
79
80
81# vi:sts=4 sw=4 et
82