pre-commit

#!/bin/sh

if git rev-parse --verify HEAD >/dev/null 2>&1
then
	against=HEAD
else
	# Initial commit: diff against an empty tree object
	against=$(git hash-object -t tree /dev/null)
fi

# Redirect output to stderr.
exec 1>&2

if ! find $(git diff-index --cached --name-only --diff-filter=AM $against) \( -name '*.cpp' -o -name '*.hpp' \) -exec bash -c 'echo -n $0 $@ | xargs -d" " -I% bash -c "clang-format --dry-run -Werror % 2> /dev/null"' {} \+ ; then
    find $(git diff-index --cached --name-only --diff-filter=AM $against) \( -name '*.cpp' -o -name '*.hpp' \) -exec bash -c 'echo -n $0 $@ | xargs -d" " -I% bash -c "clang-format --dry-run -Werror % 2> /dev/null || echo Formatting %... && clang-format -i % && git add %"' {} \+
    echo "Files have been formatted. Retry the commit."
    exit 1
fi

# If there are whitespace errors, print the offending file names and fail.
exec git diff-index --check --cached $against --