bgsc

#!/usr/bin/env python3

import argparse
import os
import re
import subprocess
import urllib.parse


parser = argparse.ArgumentParser()
parser.add_argument('action', help='action (clone, checkout)')
parser.add_argument('arg', help='argument')
args = parser.parse_args()


def update_paths(paths, branch):
    with open('.git/info/sparse-checkout', 'w') as f:
        f.write('\n'.join(paths) + '\n')
    subprocess.run(['git', 'checkout', branch]).check_returncode()

def clone(url, branch):
    parts = urllib.parse.urlparse(url)
    name = os.path.basename(parts.path)
    os.mkdir(name)
    os.chdir(name)
    subprocess.run(['git', 'init'], shell=True).check_returncode()
    subprocess.run(['git', 'config', 'core.sparseCheckout', 'true'], shell=True).check_returncode()
    subprocess.run(['git', 'remote', 'add', '-f', 'origin', url], shell=True).check_returncode()
    update_paths(['/WORKSPACE'], branch)

def checkout(target, branch):
    with open('.git/info/sparse-checkout', 'r') as f:
        paths = set(f.read().split('\n')[:-1])
    something_done = False
    if not '/WORKSPACE' in paths:
        paths.add('/WORKSPACE')
        something_done = True
    path = target[2:].split(':')[0]
    if not os.path.isfile(os.path.join(path, 'BUILD')):
        print('Adding /%s/' % (path))
        paths.add('/%s/' % (path))
        something_done = True
    if something_done:
        update_paths(paths, branch)
    steps = 0

    while True:
        cmd = ['bazel', 'query', 'deps(%s)' % (target)]
        print(' '.join(cmd))
        process = subprocess.run(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True, universal_newlines=True)
        steps += 1
        if process.returncode == 0:
            break
        else:
            nothing_done = True
            for line in process.stderr.split('\n'):
                match = re.search("Unable to load package for '//([^:']+):'", line) or re.search("no such package '([^']+)': BUILD file not found on package path and referenced", line)
                if not match is None:
                    path = '/%s/' % (match.group(1))
                    if not path in paths:
                        print('Adding', path)
                        paths.add(path)
                        nothing_done = False
            if nothing_done:
                print(process.stderr)
                return
            else:
                update_paths(paths, branch)

    print('Successfully checked out. Total steps: %d' % (steps))


branch = 'master'

if args.action == 'clone':
    clone(args.arg, branch)
elif args.action == 'checkout':
    checkout(args.arg, branch)
else:
    assert False, "Something went wrong."