#!/usr/bin/env python
# Copyright 2014 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

"""Scans build output directory for .isolated files, calculates their SHA1
hashes and stores final list in JSON document.

Used to figure out what tests were build in isolated mode to trigger these
tests to run on swarming.

For more info see:
https://sites.google.com/a/chromium.org/dev/developers/testing/isolated-testing
"""

import glob
import hashlib
import json
import optparse
import os
import re
import sys


def hash_file(filepath):
  """Calculates the hash of a file without reading it all in memory at once."""
  digest = hashlib.sha1()
  with open(filepath, 'rb') as f:
    while True:
      chunk = f.read(1024*1024)
      if not chunk:
        break
      digest.update(chunk)
  return digest.hexdigest()


def main():
  parser = optparse.OptionParser(
      usage='%prog --build-dir <path> '
          '[--output-json <path> | --clean-isolated-files]',
      description=sys.modules[__name__].__doc__)
  parser.add_option(
      '--build-dir',
      help='Path to a directory to search for *.isolated files.')
  parser.add_option(
      '--output-json',
      help='File to dump JSON results into. '
          'Mutually exclusive with --clean-isolated-files.')
  parser.add_option(
      '--clean-isolated-files',
      action='store_true',
      help='Whether to clean out all .isolated and .isolated.gen.json files. '
          'Mutually exclusive with --output-json.')

  options, _ = parser.parse_args()
  if not options.build_dir:
    parser.error('--build-dir option is required')
  if not (options.output_json or options.clean_isolated_files):
    parser.error('either --output-json or --clean-isolated-files is required')
  if options.output_json and options.clean_isolated_files:
    parser.error('only one of --output-json and '
                 '--clean-isolated-files is allowed')

  result = {}

  # Clean up generated *.isolated.gen.json files, produced by isolate_driver.py
  # in test_isolation_mode='prepare'.
  if options.clean_isolated_files:
    pattern = os.path.join(options.build_dir, '*.isolated.gen.json')
    for filepath in sorted(glob.glob(pattern)):
      os.remove(filepath)

  # Get the file hash values and output the pair.
  pattern = os.path.join(options.build_dir, '*.isolated')
  for filepath in sorted(glob.glob(pattern)):
    test_name = os.path.splitext(os.path.basename(filepath))[0]
    if re.match(r'^.+?\.\d$', test_name):
      # It's a split .isolated file, e.g. foo.0.isolated. Ignore these.
      continue

    if options.clean_isolated_files:
      # TODO(csharp): Remove deletion entirely once the isolate
      # tracked dependencies are inputs for the isolated files.
      # http://crbug.com/419031
      os.remove(filepath)
    else:
      sha1_hash = hash_file(filepath)
      result[test_name] = sha1_hash

  if options.output_json:
    with open(options.output_json, 'wb') as f:
      json.dump(result, f)

  return 0


if __name__ == '__main__':
  sys.exit(main())