format-cpp

#!/bin/bash
#
# SPDX-License-Identifier: GPL-2.0-only
#
# Copyright (C) 2020-2022 Philippe Proulx <pproulx@efficios.com>

expected_formatter_major_version=16

SCRIPT_DIR=$(dirname "$0")/

# Runs the formatter, making sure it's the expected version.
format_cpp() {
	local formatter=$1
	local version

	version=$($formatter --version)

        # shellcheck disable=SC2181
	if (($? != 0)); then
		echo "Cannot execute \`$formatter --version\`." >&2
		return 1
	fi

	if [[ "$version" != *"clang-format version $expected_formatter_major_version"* ]]; then
		echo "Expecting clang-format $expected_formatter_major_version." >&2
		echo -n Got: >&2
		echo " \`$version\`" >&2
		echo >&2
		echo "Use the FORMATTER environment variable to specify the location of clang-format $expected_formatter_major_version"
		return 1
	fi

	local root_dir

	root_dir="$(dirname "${BASH_SOURCE[0]}")"

	# Using xargs to fail as soon as the formatter fails (`-exec`
	# won't stop if its subprocess fails).
	#
	# Since clang-format 14 does not support ignore files, their
	# support is crudely emulated here.
	#
	# shellcheck disable=SC2086
	find "$root_dir" -path './src/vendor' -prune \
		-o -type f \( -name '*\.h' -o -name '*\.hpp' -o -name '*\.c' -o -name '*\.cpp' \) \
		-not -path '*/\.*' -print0 | grep -zv -f "$SCRIPT_DIR"/.clang-format-ignore | \
		xargs -P"$(nproc)" -n1 -0 $formatter -i --style=file --fallback-style=none
}

if [[ -n "$FORMATTER" ]]; then
	# Try using environment-provided formatter
	formatter=$FORMATTER
elif command -v clang-format-$expected_formatter_major_version &> /dev/null; then
	# Try using the expected version of clang-format
	formatter="clang-format-$expected_formatter_major_version"
else
	# Try using `clang-format` as is
	formatter='clang-format'
fi

# Try to format files
format_cpp "$formatter"