tools/actions/generate_compile_commands_json.py

#!/usr/bin/python3

# This reads the _compile_command files :generate_compile_commands_action
# generates a outputs a compile_commands.json file at the top of the source
# tree for things like clang-tidy to read.

# Overall usage directions: run bazel with
# --experimental_action_listener=//tools/actions:generate_compile_commands_listener
# for all the files you want to use clang-tidy with and then run this script.
# Afer that, `clang-tidy build_tests/gflags.cc` should work.

import sys
import pathlib
import os.path
import subprocess
'''
Args:
  path: The pathlib.Path to _compile_command file.
  command_directory: The directory commands are run from.

Returns a string to stick in compile_commands.json.
'''


def _get_command(path, command_directory):
    with path.open('r') as f:
        contents = f.read().split('\0')
        if len(contents) != 2:
            # Old/incomplete file or something; silently ignore it.
            return None
        return '''{
        "directory": "%s",
        "command": "%s",
        "file": "%s",
      },''' % (command_directory, contents[0].replace('"', '\\"'), contents[1])


'''
Args:
  path: A directory pathlib.Path to look for _compile_command files under.
  command_directory: The directory commands are run from.

Yields strings to stick in compile_commands.json.
'''


def _get_compile_commands(path, command_directory):
    for f in path.iterdir():
        if f.is_dir():
            yield from _get_compile_commands(f, command_directory)
        elif f.name.endswith('_compile_command'):
            command = _get_command(f, command_directory)
            if command:
                yield command


def main(argv):
    source_path = os.path.join(os.path.dirname(__file__), '../..')
    action_outs = os.path.join(
        source_path, 'bazel-bin/../extra_actions',
        'tools/actions/generate_compile_commands_action')
    command_directory = subprocess.check_output(
        ('bazel', 'info', 'execution_root'),
        cwd=source_path).decode('utf-8').rstrip()
    commands = _get_compile_commands(pathlib.Path(action_outs),
                                     command_directory)
    with open(os.path.join(source_path, 'compile_commands.json'), 'w') as f:
        f.write('[')
        for command in commands:
            f.write(command)
        f.write(']')


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