# Copyright (C) 2009 Google Inc. All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
# * Neither the name of Google Inc. nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""WebKit's Python module for interacting with patches."""
import logging
import re
_log = logging.getLogger(__name__)
INDEX_PATTERN = re.compile(r'^diff --git \w/(.+) \w/(?P<FilePath>.+)')
LINES_CHANGED_PATTERN = re.compile(
r"^@@ -(?P<OldStartLine>\d+)(,\d+)? \+(?P<NewStartLine>\d+)(,\d+)? @@")
_INITIAL_STATE = 1
_DECLARED_FILE_PATH = 2
_PROCESSING_CHUNK = 3
class DiffFile(object):
"""Contains the information for one file in a patch.
The field "lines" is a list which contains tuples in this format:
(deleted_line_number, new_line_number, line_string)
If deleted_line_number is zero, it means this line is newly added.
If new_line_number is zero, it means this line is deleted.
"""
# FIXME: Tuples generally grow into classes. We should consider
# adding a DiffLine object.
def added_or_modified_line_numbers(self):
# This logic was moved from patchreader.py, but may not be
# the right API for this object long-term.
return [line[1] for line in self.lines if not line[0]]
def __init__(self, filename):
self.filename = filename
self.lines = []
def add_new_line(self, line_number, line):
self.lines.append((0, line_number, line))
def add_deleted_line(self, line_number, line):
self.lines.append((line_number, 0, line))
def add_unchanged_line(self, deleted_line_number, new_line_number, line):
self.lines.append((deleted_line_number, new_line_number, line))
# If this is going to be called DiffParser, it should be a re-useable parser.
# Otherwise we should rename it to ParsedDiff or just Diff.
class DiffParser(object):
"""A parser for a patch file.
The field "files" is a dict whose key is the filename and value is
a DiffFile object.
"""
def __init__(self, diff_input):
"""Parses a diff.
Args:
diff_input: An iterable object.
"""
self.files = self._parse_into_diff_files(diff_input)
# FIXME: This function is way too long and needs to be broken up.
def _parse_into_diff_files(self, diff_input):
files = {}
state = _INITIAL_STATE
current_file = None
old_diff_line = None
new_diff_line = None
for line in diff_input:
line = line.rstrip('\n')
file_declaration = INDEX_PATTERN.match(line)
if file_declaration:
filename = file_declaration.group('FilePath')
current_file = DiffFile(filename)
files[filename] = current_file
state = _DECLARED_FILE_PATH
continue
lines_changed = LINES_CHANGED_PATTERN.match(line)
if lines_changed:
if state != _DECLARED_FILE_PATH and state != _PROCESSING_CHUNK:
_log.error(
'Unexpected line change without file path declaration: %r',
line)
old_diff_line = int(lines_changed.group('OldStartLine'))
new_diff_line = int(lines_changed.group('NewStartLine'))
state = _PROCESSING_CHUNK
continue
if state == _PROCESSING_CHUNK:
if line.startswith('+'):
current_file.add_new_line(new_diff_line, line[1:])
new_diff_line += 1
elif line.startswith('-'):
current_file.add_deleted_line(old_diff_line, line[1:])
old_diff_line += 1
elif line.startswith(' '):
current_file.add_unchanged_line(old_diff_line,
new_diff_line, line[1:])
old_diff_line += 1
new_diff_line += 1
elif line == '\\ No newline at end of file':
# Nothing to do. We may still have some added lines.
pass
else:
_log.error(
'Unexpected diff format when parsing a chunk: %r',
line)
return files
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