1'''
2Copyright 2011 Google Inc.
3
4Use of this source code is governed by a BSD-style license that can be
5found in the LICENSE file.
6'''
7
8import datetime
9import re
10
11def CreateParser(filepath):
12    """Returns a Parser as appropriate for the file at this filepath.
13    """
14    if (filepath.endswith('.cpp') or
15        filepath.endswith('.h') or
16        filepath.endswith('.c')):
17        return CParser()
18    else:
19        return None
20
21
22class Parser(object):
23    """Base class for all language-specific parsers.
24    """
25
26    def __init__(self):
27        self._copyright_pattern = re.compile('copyright', re.IGNORECASE)
28        self._attribute_pattern = re.compile(
29            'copyright.*\D(\d{4})\W*(\w.*[\w.])', re.IGNORECASE)
30
31    def FindCopyrightBlock(self, comment_blocks):
32        """Given a list of comment block strings, return the one that seems
33        like the most likely copyright block.
34
35        Returns None if comment_blocks was empty, or if we couldn't find
36        a comment block that contains copyright info."""
37        if not comment_blocks:
38            return None
39        for block in comment_blocks:
40            if self._copyright_pattern.search(block):
41                return block
42
43    def GetCopyrightBlockAttributes(self, comment_block):
44        """Given a comment block, return a tuple of attributes: (year, holder).
45
46        If comment_block is None, or none of the attributes are found,
47        this will return (None, None)."""
48        if not comment_block:
49            return (None, None)
50        matches = self._attribute_pattern.findall(comment_block)
51        if not matches:
52            return (None, None)
53        first_match = matches[0]
54        return (first_match[0], first_match[1])
55
56
57class CParser(Parser):
58    """Parser that knows how to parse C/C++ files.
59    """
60
61    DEFAULT_YEAR = datetime.date.today().year
62    DEFAULT_HOLDER = 'Google Inc.'
63    COPYRIGHT_BLOCK_FORMAT = '''
64/*
65 * Copyright %s %s
66 *
67 * Use of this source code is governed by a BSD-style license that can be
68 * found in the LICENSE file.
69 */
70'''
71
72    def __init__(self):
73        super(CParser, self).__init__()
74        self._comment_pattern = re.compile('/\*.*?\*/', re.DOTALL)
75
76    def FindAllCommentBlocks(self, file_contents):
77        """Returns a list of all comment blocks within these file contents.
78        """
79        return self._comment_pattern.findall(file_contents)
80
81    def CreateCopyrightBlock(self, year, holder):
82        """Returns a copyright block suitable for this language, with the
83        given attributes.
84
85        @param year year in which to hold copyright (defaults to DEFAULT_YEAR)
86        @param holder holder of copyright (defaults to DEFAULT_HOLDER)
87        """
88        if not year:
89            year = self.DEFAULT_YEAR
90        if not holder:
91            holder = self.DEFAULT_HOLDER
92        return self.COPYRIGHT_BLOCK_FORMAT % (year, holder)
93