perf completion: Strip dependency on bash-completion

# perf completion

# Taken from git.git's completion script.

__my_reassemble_comp_words_by_ref()

{

	local exclude i j first

	# Which word separators to exclude?

	exclude="${1//[^$COMP_WORDBREAKS]}"

	cword_=$COMP_CWORD

	if [ -z "$exclude" ]; then

		words_=("${COMP_WORDS[@]}")

		return

	fi

	# List of word completion separators has shrunk;

	# re-assemble words to complete.

	for ((i=0, j=0; i < ${#COMP_WORDS[@]}; i++, j++)); do

		# Append each nonempty word consisting of just

		# word separator characters to the current word.

		first=t

		while

			[ $i -gt 0 ] &&

			[ -n "${COMP_WORDS[$i]}" ] &&

			# word consists of excluded word separators

			[ "${COMP_WORDS[$i]//[^$exclude]}" = "${COMP_WORDS[$i]}" ]

		do

			# Attach to the previous token,

			# unless the previous token is the command name.

			if [ $j -ge 2 ] && [ -n "$first" ]; then

				((j--))

			fi

			first=

			words_[$j]=${words_[j]}${COMP_WORDS[i]}

			if [ $i = $COMP_CWORD ]; then

				cword_=$j

			fi

			if (($i < ${#COMP_WORDS[@]} - 1)); then

				((i++))

			else

				# Done.

				return

			fi

		done

		words_[$j]=${words_[j]}${COMP_WORDS[i]}

		if [ $i = $COMP_CWORD ]; then

			cword_=$j

		fi

	done

}

type _get_comp_words_by_ref &>/dev/null ||

_get_comp_words_by_ref()

{

	local exclude cur_ words_ cword_

	if [ "$1" = "-n" ]; then

		exclude=$2

		shift 2

	fi

	__my_reassemble_comp_words_by_ref "$exclude"

	cur_=${words_[cword_]}

	while [ $# -gt 0 ]; do

		case "$1" in

		cur)

			cur=$cur_

			;;

		prev)

			prev=${words_[$cword_-1]}

			;;

		words)

			words=("${words_[@]}")

			;;

		cword)

			cword=$cword_

			;;

		esac

		shift

	done

}

type __ltrim_colon_completions &>/dev/null ||

__ltrim_colon_completions()

{

	local cur prev cmd

	COMPREPLY=()

	if function_exists _get_comp_words_by_ref; then

	_get_comp_words_by_ref -n : cur prev

	else

		cur=$(_get_cword :)

		prev=${COMP_WORDS[COMP_CWORD-1]}

	fi

	cmd=${COMP_WORDS[0]}