1 # Copyright (C) 2009 Google Inc. All rights reserved. 2 # 3 # Redistribution and use in source and binary forms, with or without 4 # modification, are permitted provided that the following conditions are 5 # met: 6 # 7 # * Redistributions of source code must retain the above copyright 8 # notice, this list of conditions and the following disclaimer. 9 # * Redistributions in binary form must reproduce the above 10 # copyright notice, this list of conditions and the following disclaimer 11 # in the documentation and/or other materials provided with the 12 # distribution. 13 # * Neither the name of Google Inc. nor the names of its 14 # contributors may be used to endorse or promote products derived from 15 # this software without specific prior written permission. 16 # 17 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 18 # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 19 # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 20 # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 21 # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 22 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 23 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 24 # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 25 # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 26 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 27 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 28 29 """WebKit's Python module for interacting with patches.""" 30 31 import logging 32 import re 33 34 _log = logging.getLogger(__name__) 35 36 37 # FIXME: This is broken. We should compile our regexps up-front 38 # instead of using a custom cache. 39 _regexp_compile_cache = {} 40 41 42 # FIXME: This function should be removed. 43 def match(pattern, string): 44 """Matches the string with the pattern, caching the compiled regexp.""" 45 if not pattern in _regexp_compile_cache: 46 _regexp_compile_cache[pattern] = re.compile(pattern) 47 return _regexp_compile_cache[pattern].match(string) 48 49 50 # FIXME: This belongs on DiffParser (e.g. as to_svn_diff()). 51 def git_diff_to_svn_diff(line): 52 """Converts a git formatted diff line to a svn formatted line. 53 54 Args: 55 line: A string representing a line of the diff. 56 """ 57 # FIXME: This list should be a class member on DiffParser. 58 # These regexp patterns should be compiled once instead of every time. 59 conversion_patterns = (("^diff --git \w/(.+) \w/(?P<FilePath>.+)", lambda matched: "Index: " + matched.group('FilePath') + "\n"), 60 ("^new file.*", lambda matched: "\n"), 61 ("^index (([0-9a-f]{7}\.\.[0-9a-f]{7})|([0-9a-f]{40}\.\.[0-9a-f]{40})) [0-9]{6}", lambda matched: "===================================================================\n"), 62 ("^--- \w/(?P<FilePath>.+)", lambda matched: "--- " + matched.group('FilePath') + "\n"), 63 ("^\+\+\+ \w/(?P<FilePath>.+)", lambda matched: "+++ " + matched.group('FilePath') + "\n")) 64 65 for pattern, conversion in conversion_patterns: 66 matched = match(pattern, line) 67 if matched: 68 return conversion(matched) 69 return line 70 71 72 # This function exists so we can unittest get_diff_converter function 73 def svn_diff_to_svn_diff(line): 74 return line 75 76 77 # FIXME: This method belongs on DiffParser 78 def get_diff_converter(lines): 79 """Gets a converter function of diff lines. 80 81 Args: 82 lines: The lines of a diff file. 83 If this line is git formatted, we'll return a 84 converter from git to SVN. 85 """ 86 for i, line in enumerate(lines[:-1]): 87 # Stop when we find the first patch 88 if line[:3] == "+++" and lines[i + 1] == "---": 89 break 90 if match(r"^diff --git \w/", line): 91 return git_diff_to_svn_diff 92 return svn_diff_to_svn_diff 93 94 _INITIAL_STATE = 1 95 _DECLARED_FILE_PATH = 2 96 _PROCESSING_CHUNK = 3 97 98 99 class DiffFile(object): 100 """Contains the information for one file in a patch. 101 102 The field "lines" is a list which contains tuples in this format: 103 (deleted_line_number, new_line_number, line_string) 104 If deleted_line_number is zero, it means this line is newly added. 105 If new_line_number is zero, it means this line is deleted. 106 """ 107 # FIXME: Tuples generally grow into classes. We should consider 108 # adding a DiffLine object. 109 110 def added_or_modified_line_numbers(self): 111 # This logic was moved from patchreader.py, but may not be 112 # the right API for this object long-term. 113 return [line[1] for line in self.lines if not line[0]] 114 115 def __init__(self, filename): 116 self.filename = filename 117 self.lines = [] 118 119 def add_new_line(self, line_number, line): 120 self.lines.append((0, line_number, line)) 121 122 def add_deleted_line(self, line_number, line): 123 self.lines.append((line_number, 0, line)) 124 125 def add_unchanged_line(self, deleted_line_number, new_line_number, line): 126 self.lines.append((deleted_line_number, new_line_number, line)) 127 128 129 # If this is going to be called DiffParser, it should be a re-useable parser. 130 # Otherwise we should rename it to ParsedDiff or just Diff. 131 class DiffParser(object): 132 """A parser for a patch file. 133 134 The field "files" is a dict whose key is the filename and value is 135 a DiffFile object. 136 """ 137 138 def __init__(self, diff_input): 139 """Parses a diff. 140 141 Args: 142 diff_input: An iterable object. 143 """ 144 self.files = self._parse_into_diff_files(diff_input) 145 146 # FIXME: This function is way too long and needs to be broken up. 147 def _parse_into_diff_files(self, diff_input): 148 files = {} 149 state = _INITIAL_STATE 150 current_file = None 151 old_diff_line = None 152 new_diff_line = None 153 transform_line = get_diff_converter(diff_input) 154 for line in diff_input: 155 line = line.rstrip("\n") 156 line = transform_line(line) 157 158 file_declaration = match(r"^Index: (?P<FilePath>.+)", line) 159 if file_declaration: 160 filename = file_declaration.group('FilePath') 161 current_file = DiffFile(filename) 162 files[filename] = current_file 163 state = _DECLARED_FILE_PATH 164 continue 165 166 lines_changed = match(r"^@@ -(?P<OldStartLine>\d+)(,\d+)? \+(?P<NewStartLine>\d+)(,\d+)? @@", line) 167 if lines_changed: 168 if state != _DECLARED_FILE_PATH and state != _PROCESSING_CHUNK: 169 _log.error('Unexpected line change without file path ' 170 'declaration: %r' % line) 171 old_diff_line = int(lines_changed.group('OldStartLine')) 172 new_diff_line = int(lines_changed.group('NewStartLine')) 173 state = _PROCESSING_CHUNK 174 continue 175 176 if state == _PROCESSING_CHUNK: 177 if line.startswith('+'): 178 current_file.add_new_line(new_diff_line, line[1:]) 179 new_diff_line += 1 180 elif line.startswith('-'): 181 current_file.add_deleted_line(old_diff_line, line[1:]) 182 old_diff_line += 1 183 elif line.startswith(' '): 184 current_file.add_unchanged_line(old_diff_line, new_diff_line, line[1:]) 185 old_diff_line += 1 186 new_diff_line += 1 187 elif line == '\\ No newline at end of file': 188 # Nothing to do. We may still have some added lines. 189 pass 190 else: 191 _log.error('Unexpected diff format when parsing a ' 192 'chunk: %r' % line) 193 return files 194
