# Copyright (C) 2009 Google Inc. All rights reserved.
#
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# * Redistributions of source code must retain the above copyright
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# * Redistributions in binary form must reproduce the above
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# in the documentation and/or other materials provided with the
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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"""WebKit's Python module for interacting with patches."""
import logging
import re
_regexp_compile_cache = {}
def match(pattern, string):
"""Matches the string with the pattern, caching the compiled regexp."""
if not pattern in _regexp_compile_cache:
_regexp_compile_cache[pattern] = re.compile(pattern)
return _regexp_compile_cache[pattern].match(string)
def git_diff_to_svn_diff(line):
"""Converts a git formatted diff line to a svn formatted line.
Args:
line: A string representing a line of the diff.
"""
conversion_patterns = (("^diff --git \w/(.+) \w/(?P<FilePath>.+)", lambda matched: "Index: " + matched.group('FilePath') + "\n"),
("^new file.*", lambda matched: "\n"),
("^index [0-9a-f]{7}\.\.[0-9a-f]{7} [0-9]{6}", lambda matched: "===================================================================\n"),
("^--- \w/(?P<FilePath>.+)", lambda matched: "--- " + matched.group('FilePath') + "\n"),
("^\+\+\+ \w/(?P<FilePath>.+)", lambda matched: "+++ " + matched.group('FilePath') + "\n"))
for pattern, conversion in conversion_patterns:
matched = match(pattern, line)
if matched:
return conversion(matched)
return line
def get_diff_converter(first_diff_line):
"""Gets a converter function of diff lines.
Args:
first_diff_line: The first filename line of a diff file.
If this line is git formatted, we'll return a
converter from git to SVN.
"""
if match(r"^diff --git \w/", first_diff_line):
return git_diff_to_svn_diff
return lambda input: input
_INITIAL_STATE = 1
_DECLARED_FILE_PATH = 2
_PROCESSING_CHUNK = 3
class DiffFile:
"""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.
"""
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))
class DiffParser:
"""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.
"""
state = _INITIAL_STATE
self.files = {}
current_file = None
old_diff_line = None
new_diff_line = None
for line in diff_input:
line = line.rstrip("\n")
if state == _INITIAL_STATE:
transform_line = get_diff_converter(line)
line = transform_line(line)
file_declaration = match(r"^Index: (?P<FilePath>.+)", line)
if file_declaration:
filename = file_declaration.group('FilePath')
current_file = DiffFile(filename)
self.files[filename] = current_file
state = _DECLARED_FILE_PATH
continue
lines_changed = match(r"^@@ -(?P<OldStartLine>\d+)(,\d+)? \+(?P<NewStartLine>\d+)(,\d+)? @@", line)
if lines_changed:
if state != _DECLARED_FILE_PATH and state != _PROCESSING_CHUNK:
logging.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:
logging.error('Unexpected diff format when parsing a chunk: %r' % line)