1 files changed, 168 insertions, 0 deletions
diff --git a/tools/project-clang-format.py b/tools/project-clang-format.py
new file mode 100755
index 0000000..c8fde49
--- /dev/null
+++ b/tools/project-clang-format.py
@@ -0,0 +1,168 @@
+#!/usr/bin/env python3
+
+# Copyright (c) 2020 Egor Tensin <Egor.Tensin@gmail.com>
+# This file is part of the "cmake-common" project.
+# For details, see https://github.com/egor-tensin/cmake-common.
+# Distributed under the MIT License.
+
+'''clang-format all C/C++ files in the project
+
+This script feeds every C/C++ file in the repository to clang-format, either
+printing a unified diff between the original and the formatted versions, or
+formatting the files in-place.
+'''
+
+import argparse
+from contextlib import contextmanager
+import difflib
+import logging
+import os
+import subprocess
+import sys
+
+
+@contextmanager
+def setup_logging():
+    logging.basicConfig(
+        format='%(asctime)s | %(levelname)s | %(message)s',
+        datefmt='%Y-%m-%d %H:%M:%S',
+        level=logging.INFO)
+    try:
+        yield
+    except Exception as e:
+        logging.exception(e)
+        raise
+
+
+@contextmanager
+def cd(path):
+    cwd = os.getcwd()
+    os.chdir(path)
+    try:
+        yield
+    finally:
+        os.chdir(cwd)
+
+
+def run(cmd_line):
+    logging.debug('Running executable: %s', cmd_line)
+    try:
+        return subprocess.run(cmd_line, check=True, universal_newlines=True,
+                              stderr=subprocess.STDOUT, stdout=subprocess.PIPE)
+    except subprocess.CalledProcessError as e:
+        logging.error('Process finished with exit code %d: %s', e.returncode, cmd_line)
+        logging.error('Its output was:\n%s', e.output)
+        raise
+
+
+def read_file(path):
+    with open(path) as file:
+        return file.read()
+
+
+class ClangFormat:
+    def __init__(self, path, style):
+        self.path = path
+        self.style = style
+
+    def _get_command_line(self, paths, in_place=False):
+        cmd_line = [self.path, f'-style={self.style}']
+        if in_place:
+            cmd_line.append('-i')
+        cmd_line.append('--')
+        cmd_line += list(paths)
+        return cmd_line
+
+    def format_in_place(self, paths):
+        run(self._get_command_line(paths, in_place=True))
+
+    @staticmethod
+    def _show_diff(path, formatted):
+        original = read_file(path).split('\n')
+        formatted = formatted.split('\n')
+        original_lbl = f'{path} (original)'
+        formatted_lbl = f'{path} (formatted)'
+
+        diff = difflib.unified_diff(original, formatted, fromfile=original_lbl,
+                                    tofile=formatted_lbl, lineterm='')
+
+        clean = True
+        for line in diff:
+            clean = False
+            print(line)
+        return clean
+
+    def show_diff(self, paths):
+        clean = True
+        for path in paths:
+            formatted = run(self._get_command_line([path])).stdout
+            clean = self._show_diff(path, formatted) and clean
+        return clean
+
+
+def git_root_dir():
+    cmd_line = ['git', 'rev-parse', '--show-toplevel']
+    root_dir = run(cmd_line).stdout
+    if root_dir[-1] != '\n':
+        raise RuntimeError('git rev-parse --show-toplevel should append a newline?')
+    return root_dir[:-1]
+
+
+def list_all_files():
+    cmd_line = ['git', 'ls-tree', '-r', '-z', '--name-only', 'HEAD']
+    repo_files = run(cmd_line).stdout
+    repo_files = repo_files.split('\0')
+    return repo_files
+
+
+CPP_FILE_EXTENSIONS = {'.c', '.h', '.cc', '.hh', '.cpp', '.hpp', '.cxx', '.hxx', '.cp', '.c++'}
+
+
+def list_cpp_files():
+    for path in list_all_files():
+        ext = os.path.splitext(path)[1]
+        if ext in CPP_FILE_EXTENSIONS:
+            yield path
+
+
+def process_cpp_files(args):
+    clang_format = ClangFormat(args.clang_format, args.style)
+    with cd(git_root_dir()):
+        cpp_files = list_cpp_files()
+        if args.in_place:
+            clang_format.format_in_place(cpp_files)
+        else:
+            if not clang_format.show_diff(cpp_files):
+                sys.exit(1)
+
+
+DEFAULT_CLANG_FORMAT = 'clang-format'
+DEFAULT_STYLE = 'file'
+
+
+def parse_args(argv=None):
+    if argv is None:
+        argv = sys.argv[1:]
+
+    parser = argparse.ArgumentParser(
+        description=__doc__,
+        formatter_class=argparse.RawDescriptionHelpFormatter)
+
+    parser.add_argument('-b', '--clang-format', default=DEFAULT_CLANG_FORMAT,
+                        help='clang-format executable file path')
+    parser.add_argument('-s', '--style', default=DEFAULT_STYLE,
+                        help='clang-format -style parameter argument')
+    parser.add_argument('-i', '--in-place', action='store_true',
+                        help='edit the files in-place')
+
+    return parser.parse_args(argv)
+
+
+def main(argv=None):
+    args = parse_args(argv)
+    with setup_logging():
+        process_cpp_files(args)
+
+
+if __name__ == '__main__':
+    main()