#!/usr/bin/env python

"""Retrieves commit contents in a patch format.

Check README.md for usage examples or run it with `-h` argument to get an interface reference.

"""

import argparse

import os

import sys

from lib.git import get_patch as git_get_patch

def parse_args():

parser = argparse.ArgumentParser(

description='Get a commit contents in a patch format.')

parser.add_argument('-c', '--commit', nargs='+', required=True,

help='Commit hash(es).')

parser.add_argument('-f', '--filename', nargs='*', required=False,

help='Filename(s) for a patch file(s). Defaults to something like {0}.'

.format(get_default_patch_file_name(

'4b825dc642cb6eb9a060e54bf8d69288fbee4904')))

parser.add_argument('-o', '--output-dir', required=False,

help='Folder to save the patch in. Defaults to a current folder.')

parser.add_argument('-r', '--repo', required=True,

help='Path to a repository root folder.')

args = parser.parse_args()

# Additional rules

if args.filename is not None and (len(args.commit) != len(args.filename)):

parser.error("Number of filenames ({0}) must be equal to number of commits ({1})."

.format(len(args.filename), len(args.commit)))

return args

def get_default_patch_file_name(commit_hash):

template = 'backport_{commit_hash}.patch'

number_of_hash_characters_to_preserve = 8

commit_hash_string = commit_hash[:number_of_hash_characters_to_preserve+1]

patch_file_name = template.format(

commit_hash=commit_hash_string)

return patch_file_name

def get_output_path(output_dir, output_filename, commit_hash):

if (output_dir is None) and (output_filename is None):

return None

# Use current dir as a default.

if output_dir is None:

output_dir = '.'

# Use the default filename if it's not provided.

if output_filename is None:

output_filename = get_default_patch_file_name(commit_hash)

output_path = os.path.join(output_dir, output_filename)

return output_path

def save_to_file(data, file_path):

with open(file_path, 'w') as f:

f.write(data)

def process_patch(repo, commit_hash, output_path=None):

patch_contents = git_get_patch(repo, commit_hash)

if output_path is None:

sys.stdout.write(patch_contents)

else:

save_to_file(data=patch_contents, file_path=output_path)

def main():

args = parse_args()

commits = args.commit

filenames = args.filename

# (alexeykuzmin): Ugly hack alert.

if filenames is None:

filenames = [None] * len(commits)

for (commit, filename) in zip(commits, filenames):

output_path = get_output_path(args.output_dir, filename,

commit_hash=commit)

process_patch(args.repo, commit, output_path)

return 0

if __name__ == '__main__':

sys.exit(main())