git-clang-format.py

#!/usr/bin/env python

import os
import subprocess
import sys

PATH = os.environ["PATH"]
if '/usr/local/bin' not in PATH:
    PATH = "/usr/local/bin:{}".format(PATH)
env = {"PATH": PATH}

print >> sys.stdout, "Running pre-commit hook for `git clang-format`..."
sys.stdout.flush()

output = subprocess.check_output(["git-clang-format", "--diff"], env=env)

success_messages = (
    'no modified files to format',
    'clang-format did not modify any files')

if output and not any(map(lambda m: m in output, success_messages)):
    print >> sys.stderr, "clang-format found the files with peding formatting:"
    for line in output.split("\n"):
        if line.startswith("+++"):
            print >> sys.stderr, "  ", line.split("/")[-1]
    exit(1)
exit(0)