bash backtrace

gistfile1.txt

#!/usr/bin/env bash

function throw(){
    local msg="${1}"

    _ERR_MSG_="$msg"

    kill -s USR2 $BASHPID
}

function backtrace
{
  # Hide the traceback() call.
  local -i cnt=${#BASH_SOURCE[@]} # call stack 共 N 個, [0..N-1]
  local -i start=$(( ${1:-0} ))
  local -i end=$(( $cnt - 1 ))
  local -i i=0
  local -i max1=0
  local -i max2=0

  max1=$( for (( k=$start+1; k <=$end; k++ )); do echo "${BASH_SOURCE[$k]}" ; done  | wc --max-line-length )
  max2=$( for (( k=$start  ; k <=$end; k++ )); do echo "${BASH_LINENO[$k]}" ; done  | wc --max-line-length )

  (
  printf "\n"
  printf "+----------------------------------\n"
  printf "|Traceback (most recent call last):\n"
  for ((i=${end}; i >= ${start}; i--)); do
    local func="${FUNCNAME[$i]}"
    local file="${BASH_SOURCE[$i+1]}"
    [ $i -eq $end ] && file="${BASH_SOURCE[$end]}" # 效正最後的邊界值
    local line="${BASH_LINENO[$i]}"
    local padding=$(( $end - $i + 3 ))
    printf "| %${max1}s:%-${max2}s %${padding}s %s()\n" "${file}" "${line}" "\\->" "${func}"
  done
  printf "+----------------------------------\n"
  ) | perl -pe 's/^/  /g' | perl -pe 's/^\s*$//g' | cat 1>&2

}

function set_err_policy(){
    local policy="$1"
    local -i cnt=${#BASH_SOURCE[@]} # call stack 共 N 個, [0..N-1]
    local -i end=$(( $cnt - 1 ))
    local -i i=1

    local func="${FUNCNAME[$i]}"
    local file="${BASH_SOURCE[$i+1]}"
    [ $i -eq $end ] && file="${BASH_SOURCE[$end]}" # 效正最後的邊界值
    local line="${BASH_LINENO[$i]}"

    local file="$( echo $file | perl -pe 's/\./_/g' | perl -pe 's/\//_/g' )"
    export ${file}_${line}_${func}="$policy"
}

function get_err_policy(){
  # Hide the traceback() call.
  local -i cnt=${#BASH_SOURCE[@]} # call stack 共 N 個, [0..N-1]
  local -i start=$(( ${1:-0} + 1 ))
  local -i end=$(( $cnt - 1 ))
  local -i i=0

  local res=""
  for (( i=${start}; i <= ${end}; i++ )); do
    local func="${FUNCNAME[$i]}"
    local file="${BASH_SOURCE[$i+1]}"
    [ $i -eq $end ] && file="${BASH_SOURCE[$end]}" # 效正最後的邊界值
    local line="${BASH_LINENO[$i]}"

    local file="$( echo $file | perl -pe 's/\./_/g' | perl -pe 's/\//_/g' )"
    local policy=$( eval "echo \${${file}_${line}_${func}}" )
    [ -n "$policy" ] && res="$policy" && break
    #printf " %s_%s_%s => %s\n" "${file}" "${line}" "${func}" "$policy" 1>&2
  done

  echo $res
}

function _err_handler(){
    local _err_code="$?"
    local _err_msg="$_EX_MSG_" ; unset _ERR_MSG_
    local _err_policy=$( get_err_policy 1 )

    [ $_err_code -ne 99 ] && [ $_err_policy != "silent" ] && backtrace 1 # 若不是 bubble 的 error event, 就 show backtrace ( 除了 silent 外 )

    case "$_err_policy" in
        silent) {
            return 0;
        }

        ;;
        keepgoing) {
            return 0;
        }
        ;;

        bubble) {
            [ ${#BASH_SOURCE[@]} -gt 2 ] && return 99 || exit 99
        }
        ;;

        *) {
            return 0;
        }
        ;;
    esac
}

function _err_handling_eval_(){
    cat <<-EOD
	set -o errtrace;
	trap "_err_handler || return 99;"           ERR;
	trap "backtrace 1; return 99;"              USR2;
	trap "[ \\\$? -ne 99 -a \\\$? -ne 0 ] && { backtrace 1; }" EXIT;
	EOD
}