text: #!/usr/bin/env python
  #
  #===- run-clang-tidy.py - Parallel clang-tidy runner ---------*- python -*--===#
  #
  # Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  # See https://llvm.org/LICENSE.txt for license information.
  # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  #
  #===------------------------------------------------------------------------===#
  # FIXME: Integrate with clang-tidy-diff.py
  # NOTE: Original in: https://github.com/llvm-mirror/clang-tools-extra/blob/master/clang-tidy/tool/run-clang-tidy.py
  
  """
  Parallel clang-tidy runner
  ==========================
  
  Runs clang-tidy over all files in a compilation database. Requires clang-tidy
  and clang-apply-replacements in $PATH.
  
  Example invocations.
  - Run clang-tidy on all files in the current working directory with a default
    set of checks and show warnings in the cpp files and all project headers.
      run-clang-tidy.py $PWD
  
  - Fix all header guards.
      run-clang-tidy.py -fix -checks=-*,llvm-header-guard
  
  - Fix all header guards included from clang-tidy and header guards
    for clang-tidy headers.
      run-clang-tidy.py -fix -checks=-*,llvm-header-guard extra/clang-tidy \
                        -header-filter=extra/clang-tidy
  
  Compilation database setup:
  http://clang.llvm.org/docs/HowToSetupToolingForLLVM.html
  """
  
  from __future__ import print_function
  
  import argparse
  import glob
  import json
  import multiprocessing
  import os
  import re
  import shutil
  import subprocess
  import sys
  import tempfile
  import threading
  import traceback
  
  try:
    import yaml
  except ImportError:
    yaml = None
  
  is_py2 = sys.version[0] == '2'
  
  if is_py2:
      import Queue as queue
  else:
      import queue as queue
  
  def find_compilation_database(path):
    """Adjusts the directory until a compilation database is found."""
    result = './'
    while not os.path.isfile(os.path.join(result, path)):
      if os.path.realpath(result) == '/':
        print('Error: could not find compilation database.')
        sys.exit(1)
      result += '../'
    return os.path.realpath(result)
  
  
  def make_absolute(f, directory):
    if os.path.isabs(f):
      return f
    return os.path.normpath(os.path.join(directory, f))
  
  
  def get_tidy_invocation(f, clang_tidy_binary, checks, tmpdir, build_path,
                          header_filter, extra_arg, extra_arg_before, quiet,
                          config):
    """Gets a command line for clang-tidy."""
    start = [clang_tidy_binary]
    if header_filter is not None:
      start.append('-header-filter=' + header_filter)
    if checks:
      start.append('-checks=' + checks)
    if tmpdir is not None:
      start.append('-export-fixes')
      # Get a temporary file. We immediately close the handle so clang-tidy can
      # overwrite it.
      (handle, name) = tempfile.mkstemp(suffix='.yaml', dir=tmpdir)
      os.close(handle)
      start.append(name)
    for arg in extra_arg:
        start.append('-extra-arg=%s' % arg)
    for arg in extra_arg_before:
        start.append('-extra-arg-before=%s' % arg)
    start.append('-p=' + build_path)
    if quiet:
        start.append('-quiet')
    if config:
        start.append('-config=' + config)
    start.append(f)
    return start
  
  
  def merge_replacement_files(tmpdir, mergefile):
    """Merge all replacement files in a directory into a single file"""
    # The fixes suggested by clang-tidy >= 4.0.0 are given under
    # the top level key 'Diagnostics' in the output yaml files
    mergekey="Diagnostics"
    merged=[]
    for replacefile in glob.iglob(os.path.join(tmpdir, '*.yaml')):
      content = yaml.safe_load(open(replacefile, 'r'))
      if not content:
        continue # Skip empty files.
      merged.extend(content.get(mergekey, []))
  
    if merged:
      # MainSourceFile: The key is required by the definition inside
      # include/clang/Tooling/ReplacementsYaml.h, but the value
      # is actually never used inside clang-apply-replacements,
      # so we set it to '' here.
      output = { 'MainSourceFile': '', mergekey: merged }
      with open(mergefile, 'w') as out:
        yaml.safe_dump(output, out)
    else:
      # Empty the file:
      open(mergefile, 'w').close()
  
  
  def check_clang_apply_replacements_binary(args):
    """Checks if invoking supplied clang-apply-replacements binary works."""
    try:
      subprocess.check_call([args.clang_apply_replacements_binary, '--version'])
    except:
      print('Unable to run clang-apply-replacements. Is clang-apply-replacements '
            'binary correctly specified?', file=sys.stderr)
      traceback.print_exc()
      sys.exit(1)
  
  
  def apply_fixes(args, tmpdir):
    """Calls clang-apply-fixes on a given directory."""
    invocation = [args.clang_apply_replacements_binary]
    if args.format:
      invocation.append('-format')
    if args.style:
      invocation.append('-style=' + args.style)
    invocation.append(tmpdir)
    subprocess.call(invocation)
  
  
  def run_tidy(args, tmpdir, build_path, queue, lock, failed_files):
    """Takes filenames out of queue and runs clang-tidy on them."""
    while True:
      name = queue.get()
      invocation = get_tidy_invocation(name, args.clang_tidy_binary, args.checks,
                                       tmpdir, build_path, args.header_filter,
                                       args.extra_arg, args.extra_arg_before,
                                       args.quiet, args.config)
  
      proc = subprocess.Popen(invocation, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
      output, err = proc.communicate()
      if proc.returncode != 0:
        failed_files.append(name)
      with lock:
        sys.stdout.write(' '.join(invocation) + '\n' + output.decode('utf-8'))
        if len(err) > 0:
          sys.stdout.flush()
          sys.stderr.write(err.decode('utf-8'))
      queue.task_done()
  
  
  def main():
    parser = argparse.ArgumentParser(description='Runs clang-tidy over all files '
                                     'in a compilation database. Requires '
                                     'clang-tidy and clang-apply-replacements in '
                                     '$PATH.')
    parser.add_argument('-clang-tidy-binary', metavar='PATH',
                        default='clang-tidy',
                        help='path to clang-tidy binary')
    parser.add_argument('-clang-apply-replacements-binary', metavar='PATH',
                        default='clang-apply-replacements',
                        help='path to clang-apply-replacements binary')
    parser.add_argument('-checks', default=None,
                        help='checks filter, when not specified, use clang-tidy '
                        'default')
    parser.add_argument('-config', default=None,
                        help='Specifies a configuration in YAML/JSON format: '
                        '  -config="{Checks: \'*\', '
                        '                       CheckOptions: [{key: x, '
                        '                                       value: y}]}" '
                        'When the value is empty, clang-tidy will '
                        'attempt to find a file named .clang-tidy for '
                        'each source file in its parent directories.')
    parser.add_argument('-header-filter', default=None,
                        help='regular expression matching the names of the '
                        'headers to output diagnostics from. Diagnostics from '
                        'the main file of each translation unit are always '
                        'displayed.')
    if yaml:
      parser.add_argument('-export-fixes', metavar='filename', dest='export_fixes',
                          help='Create a yaml file to store suggested fixes in, '
                          'which can be applied with clang-apply-replacements.')
    parser.add_argument('-j', type=int, default=0,
                        help='number of tidy instances to be run in parallel.')
    parser.add_argument('files', nargs='*', default=['.*'],
                        help='files to be processed (regex on path)')
    parser.add_argument('-fix', action='store_true', help='apply fix-its')
    parser.add_argument('-format', action='store_true', help='Reformat code '
                        'after applying fixes')
    parser.add_argument('-style', default='file', help='The style of reformat '
                        'code after applying fixes')
    parser.add_argument('-p', dest='build_path',
                        help='Path used to read a compile command database.')
    parser.add_argument('-extra-arg', dest='extra_arg',
                        action='append', default=[],
                        help='Additional argument to append to the compiler '
                        'command line.')
    parser.add_argument('-extra-arg-before', dest='extra_arg_before',
                        action='append', default=[],
                        help='Additional argument to prepend to the compiler '
                        'command line.')
    parser.add_argument('-quiet', action='store_true',
                        help='Run clang-tidy in quiet mode')
    args = parser.parse_args()
  
    db_path = 'compile_commands.json'
  
    if args.build_path is not None:
      build_path = args.build_path
    else:
      # Find our database
      build_path = find_compilation_database(db_path)
  
    try:
      invocation = [args.clang_tidy_binary, '-list-checks']
      invocation.append('-p=' + build_path)
      if args.checks:
        invocation.append('-checks=' + args.checks)
      invocation.append('-')
      if args.quiet:
        # Even with -quiet we still want to check if we can call clang-tidy.
        with open(os.devnull, 'w') as dev_null:
          subprocess.check_call(invocation, stdout=dev_null)
      else:
        subprocess.check_call(invocation)
    except:
      print("Unable to run clang-tidy.", file=sys.stderr)
      sys.exit(1)
  
    # Load the database and extract all files.
    database = json.load(open(os.path.join(build_path, db_path)))
    files = [make_absolute(entry['file'], entry['directory'])
             for entry in database]
  
    max_task = args.j
    if max_task == 0:
      max_task = multiprocessing.cpu_count()
  
    tmpdir = None
    if args.fix or (yaml and args.export_fixes):
      check_clang_apply_replacements_binary(args)
      tmpdir = tempfile.mkdtemp()
  
    # Build up a big regexy filter from all command line arguments.
    file_name_re = re.compile('|'.join(args.files))
  
    return_code = 0
    try:
      # Spin up a bunch of tidy-launching threads.
      task_queue = queue.Queue(max_task)
      # List of files with a non-zero return code.
      failed_files = []
      lock = threading.Lock()
      for _ in range(max_task):
        t = threading.Thread(target=run_tidy,
                             args=(args, tmpdir, build_path, task_queue, lock, failed_files))
        t.daemon = True
        t.start()
  
      # Fill the queue with files.
      for name in files:
        if file_name_re.search(name):
          task_queue.put(name)
  
      # Wait for all threads to be done.
      task_queue.join()
      if len(failed_files):
        return_code = 1
  
    except KeyboardInterrupt:
      # This is a sad hack. Unfortunately subprocess goes
      # bonkers with ctrl-c and we start forking merrily.
      print('\nCtrl-C detected, goodbye.')
      if tmpdir:
        shutil.rmtree(tmpdir)
      os.kill(0, 9)
  
    if yaml and args.export_fixes:
      print('Writing fixes to ' + args.export_fixes + ' ...')
      try:
        merge_replacement_files(tmpdir, args.export_fixes)
      except:
        print('Error exporting fixes.\n', file=sys.stderr)
        traceback.print_exc()
        return_code=1
  
    if args.fix:
      print('Applying fixes ...')
      try:
        apply_fixes(args, tmpdir)
      except:
        print('Error applying fixes.\n', file=sys.stderr)
        traceback.print_exc()
        return_code=1
  
    if tmpdir:
      shutil.rmtree(tmpdir)
    sys.exit(return_code)
  
  if __name__ == '__main__':
    main()
  