vim-pack-parallel

#! /usr/bin/env bash
# Check if parallel is installed

parallel_short_opts="j:gml"
parallel_long_opts="jobs:,gnu-parallel,moreutils-parallel,loop"

has_gnu=false
has_more=false
use_gnu=false
use_more=false

if which parallel > /dev/null; then
	# Check if parallel is gnu parallel or moreutils
	if parallel -V > /dev/null &> /dev/null; then
		has_gnu=true
	else
		has_more=true
		moreutils_parallel=parallel
	fi
	if which parallel.moreutils > /dev/null; then
		has_more=true
		moreutils_parallel=parallel.moreutils
	fi
fi

if [[ $has_more == true ]] && [[ $has_gnu == true ]]; then
	use_gnu=true
elif [[ $has_more == true ]] && [[ $has_gnu == false ]]; then
	use_more=true
fi

# Check number of virtual cores in system and set default number of jobs to that
jobs=$(nproc)

parallel_parse_opt() {
	case "$1" in
		-g|--gnu-parallel)
			if [[ "$has_gnu" == false ]]; then
				echo "GNU Parallel not installed"
				exit 1
			fi
			use_gnu=true
			use_more=false
			return 1
			;;
		-l|--loop)
			use_gnu=false
			use_more=false
			return 1
			;;
		-m|--moreutils-parallel)
			if [[ "$has_more" == false ]]; then
				echo "Moreutils Parallel not installed"
				exit 1
			fi
			use_gnu=false
			use_more=true
			return 1
			;;
		-j|--jobs)
			jobs="$2"
			return 2
			;;
		*)
			return 0
			;;
	esac
}

_run_more() {
	$moreutils_parallel -i -j "$jobs" \
		bash -c "$1" \
		-- "${@:2}"
}

_run_gnu() {
	cmd="$1"
	shift
	parallel -j "$jobs" --nn \
		"$cmd" \
		::: "${@:2}"
}

_run_loop() {
	for i in "${@:2}";
	do
		bash -c "${1//\{\}/$i}"
	done
}

parallel_run() {
	if [[ $use_more == true ]]; then
		_run_more "$@"
	elif [[ $use_gnu == true ]]; then
		_run_gnu "$@"
	else
		_run_loop "$@"
	fi
}

parallel_usage_options() {
	echo 'multithreading options:'
	echo '    -j| --jobs <num jobs>'
	echo '        Will run with <num jobs> jobs. The default value is value is 1 job per virtual'
	echo "        core provided by the command nproc. On this system the default is $(nproc) jobs"
	echo '        if -l|--loop flag is provided this flag does nothing'
	echo
	echo '    -g|--gnu-parallel'
	echo '        Use GNU parallel library to run code concurently'
	echo
	echo '    -l|--loop'
	echo '        Run code in an itterative loop'
	echo
	echo '    -m|--moreutils-parallel'
	echo '        Use moreutils parallel library to run code concurently'
}

parallel_usage_notes() {
	echo '       Multithreading works if moreutils parallel xor GNU parallel is installed otherwise it'
	echo '       will do nothing.'
	if [[ $has_gnu == true ]]; then
		echo '       This system has GNU parallel installed'
	fi
	if [[ $has_more == true ]]; then
		echo '       This system has moreutils parallel installed'
	fi
	if [[ $has_more == false ]] && [[ $has_gnu == false ]]; then
		echo '       This system has no parallel library installed'
	fi
}