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#!/usr/bin/env python3
##
## Copyright (c) 2016, Alliance for Open Media. All rights reserved.
##
## This source code is subject to the terms of the BSD 2 Clause License and
## the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
## was not distributed with this source code in the LICENSE file, you can
## obtain it at www.aomedia.org/license/software. If the Alliance for Open
## Media Patent License 1.0 was not distributed with this source code in the
## PATENTS file, you can obtain it at www.aomedia.org/license/patent.
##
"""Calculates the "intersection" of two unified diffs.
Given two diffs, A and B, it finds all hunks in B that had non-context lines
in A and prints them to stdout. This is useful to determine the hunks in B that
are relevant to A. The resulting file can be applied with patch(1) on top of A.
"""
__author__ = "jkoleszar@google.com"
import sys
import diff
def FormatDiffHunks(hunks):
"""Re-serialize a list of DiffHunks."""
r = []
last_header = None
for hunk in hunks:
this_header = hunk.header[0:2]
if last_header != this_header:
r.extend(hunk.header)
last_header = this_header
else:
r.extend(hunk.header[2])
r.extend(hunk.lines)
r.append("\n")
return "".join(r)
def ZipHunks(rhs_hunks, lhs_hunks):
"""Join two hunk lists on filename."""
for rhs_hunk in rhs_hunks:
rhs_file = rhs_hunk.right.filename.split("/")[1:]
for lhs_hunk in lhs_hunks:
lhs_file = lhs_hunk.left.filename.split("/")[1:]
if lhs_file != rhs_file:
continue
yield (rhs_hunk, lhs_hunk)
def main():
old_hunks = [x for x in diff.ParseDiffHunks(open(sys.argv[1], "r"))]
new_hunks = [x for x in diff.ParseDiffHunks(open(sys.argv[2], "r"))]
out_hunks = []
# Join the right hand side of the older diff with the left hand side of the
# newer diff.
for old_hunk, new_hunk in ZipHunks(old_hunks, new_hunks):
if new_hunk in out_hunks:
continue
old_lines = old_hunk.right
new_lines = new_hunk.left
# Determine if this hunk overlaps any non-context line from the other
for i in old_lines.delta_line_nums:
if i in new_lines:
out_hunks.append(new_hunk)
break
if out_hunks:
print(FormatDiffHunks(out_hunks))
sys.exit(1)
if __name__ == "__main__":
main()