UpdateController/general_utils

#! /bin/bash -
# set -x 

source ./log_helpers

if [ "${general_utils_sourced:-1}" = "1" ]; then    # include only once
    readonly general_utils_sourced=${BASH_SOURCE[0]}

    # compare two strings
    equal () {
        case "$1" in
            "$2")   
                return 0
                ;;
        esac
        return 1    # they don't match
    }

    # check if second string is contained in first string
    contains () {
        if grep -qE "$2" <<< $1; then
            return 0
        fi
        return 1    # not contained
    }

    exec_process_substitution () {
        local func="${FUNCNAME[0]}"
        log_debug "$func:${LINENO} exec-ing [$*]"

        exec {fd}< <(eval "$@")

        local __result_code=$?
        local ps_pid=$!  # remember pid of process substitution

        local __result=""

        while read __tmp <&$fd; do
            if ! [ -z "$__tmp" ]; then
                __result+=" $__tmp"
            fi
        done

        exec {fd}>&-    # close fd (i.e. process substitution)
        wait $ps_pid    # wait for the subshell to finish

        __result=${__result//[$'\r\n\t']/ } # remove \r\n\t from __result

        log_debug "$func:${LINENO} result=$__result"
        printf '%s' "$__result"
        return $__result_code
    }
    # exec_process_substitution 'opkg --noaction list'

    usage () {
        echo "Usage: $PROGRAM [--file config] [--?] [--help] [--version] [--dbg]" 
        # UpdateController.conf"
    }

    usage_and_exit () {
        usage
        exit $1
    }

    version () {
        echo "$PROGRAM version $VERSION"
    }

    error () {
        echo "$@" 1>&2
        usage_and_exit 1
    }

    alert () {
        # usage: alert <$?> <object>
        if [ "$1" ne 0 ]; then
            echo "WARNING: $2 did not complete successfully." >&2
            exit 1
        else
            echo "INFO: $2 completed successfully" >&2
        fi
    }
fi