# Copyright (c) 2017 The NetBSD Foundation, Inc.
# All rights reserved.
#
# This code is derived from software contributed to The NetBSD Foundation
# by Johnny C. Lam.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
# ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
# TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
# PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
# BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
#
# NAME
#	echo.subr -- write to standard output through a buffer
#
# SYNOPSIS
#	task_echo [-bcn] ...
#
# DESCRIPTION
#	The task_echo function provides a buffered output facility.  It
#	write the contents of the shared buffer to the standard output, then
#	writes the operands, separated by a single blank character and
#	followed by a newline character, to the standard output.
#
#	The options are as follows:
#
#	-b	Write the operands into a shared buffer instead of to the
#		standard output.
#
#	-c	Clear the contents of the shared buffer before writing the
#		operands.
#
#	-n	Do not write the trailing newline character.
#
# RETURN VALUES
#	Returns 0 on success, and >0 if an error occurs.
#
# ENVIRONMENT
#	The following variables are used if they are set:
#
#	TASK_LOGFILE
#		The location of the log file for appending a duplicate of
#		the output.  If this variable is unset or empty, then no log
#		output is written.
#
# EXAMPLES
#	task_echo -bcn "Only write this if there is at least one argument:"
#	for arg; do
#		task_echo "    $arg"
#	done
#

__task_echo__="yes"

task_load tee

task_echo()
{
	: ${TASK_LOGFILE:=}

	local action="echo"
	local newline="
"
	local arg
	local OPTIND=1
	while getopts ":bcn" arg "$@"; do
		case $arg in
		b)	action="buffer" ;;
		c)	__task_echo_buffer__= ;;
		n)	newline= ;;
		*)	echo 1>&2 "${0##*/}: task_echo: unknown option \`$arg'" ;;
		esac
	done
	shift $(( ${OPTIND} - 1 ))

	case $action in
	buffer)	case $newline in
		"")	__task_echo_buffer__="$__task_echo_buffer__""$@" ;;
		*)	__task_echo_buffer__="$__task_echo_buffer__""$@""$newline" ;;
		esac ;;
	echo)	case ${TASK_LOGFILE} in
		"")	case $newline in
			"")	echo -n "$__task_echo_buffer__""$@" ;;
			*)	echo "$__task_echo_buffer__""$@" ;;
			esac ;;
		*)	case $newline in
			"")	echo -n "$__task_echo_buffer__""$@" ;;
			*)	echo "$__task_echo_buffer__""$@" ;;
			esac | task_tee -a "${TASK_LOGFILE}" ;;
		esac
		__task_echo_buffer__= ;;

	esac
	return 0
}

# Static variable to hold the buffered output.
__task_echo_buffer__=