bash debugger Code

# -*- shell-script -*-
# fns.sh - Debugger Utility Functions
#
#   Copyright (C) 2002-2011 2019 2021
#   Rocky Bernstein <rocky@gnu.org>
#
#   This program is free software; you can redistribute it and/or
#   modify it under the terms of the GNU General Public License as
#   published by the Free Software Foundation; either version 2, or
#   (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
#   General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this program; see the file COPYING.  If not, write to
#   the Free Software Foundation, 59 Temple Place, Suite 330, Boston,
#   MA 02111 USA.

typeset -a _Dbg_yn; _Dbg_yn=("n" "y")

# Return $2 copies of $1. If successful, $? is 0 and the return value
# is in _Dbg_result.  Otherwise $? is 1 and _Dbg_result ''
function _Dbg_copies {
    _Dbg_result=''
    (( $# < 2 )) && return 1
    typeset -r string="$1"
    typeset -i count=$2 || return 2
    (( count > 0 )) || return 3
    builtin printf -v _Dbg_result "%${count}s" ' ' || return 3
    _Dbg_result=${_Dbg_result// /$string}
    return 0
}

# _Dbg_defined returns 0 if $1 is a defined variable or nonzero otherwise.
_Dbg_defined() {
    (( 0 == $# )) && return 1

    if (( (BASH_VERSINFO[0] > 4) ||
          (BASH_VERSINFO[0] == 4 && BASH_VERSINFO[1] >= 2) )); then
	# Without the eval below, bash > 4.2 will barf. The quotes
	# hide invalid lingo for earlier bash..
	eval "[[ -v \"$1\" ]]"
    else
	typeset -p "$1" &> /dev/null
    fi
}

# Add escapes to a string $1 so that when it is read back via "$1"
# it is the same as $1.
function _Dbg_esc_dq {
  builtin printf "%q\n" "$1"
}

# We go through the array indirection below because bash (but not ksh)
# gives syntax errors when this is put in place.
typeset -a _Dbg_eval_re;
_Dbg_eval_re=(
    '^[[:blank:]]*(if|elif)[[:blank:]]+([^;]*)((;[[:blank:]]*then?)?|$)'
    '^[[:blank:]]*return[[:blank:]]+(.*)$'
    '^[[:blank:]]*while[[:blank:]]+([^;]*)((;[[:blank:]]*do?)?|$)'
    '^[[:blank:]]*[A-Za-z_][A-Za-z_0-9_]*[+-]?=(.*$)'
    "^[[:blank:]]*[A-Za-z_][A-Za-z_0-9_]*\[[0-9]+\][+-]?=(.*\$)"
)

# Removes "[el]if" .. "; then" or "while" .. "; do" or "return .."
# leaving resumably the expression part.  This function is called by
# the eval?  command where we want to evaluate the expression part in
# a source line of code
_Dbg_eval_extract_condition()
{
    orig="$1"
    if [[ $orig =~ ${_Dbg_eval_re[0]} ]] ; then
	extracted=${BASH_REMATCH[2]}
    elif [[ $orig =~ ${_Dbg_eval_re[1]} ]] ; then
	extracted="echo ${BASH_REMATCH[1]}"
    elif [[ $orig =~ ${_Dbg_eval_re[2]} ]] ; then
	extracted=${BASH_REMATCH[1]}
    elif [[ $orig =~ ${_Dbg_eval_re[3]} ]] ; then
	extracted="echo ${BASH_REMATCH[1]}"
    elif [[ $orig =~ ${_Dbg_eval_re[4]} ]] ; then
	extracted="echo ${BASH_REMATCH[1]}"
    else
	extracted=$orig
    fi
}

# Print "on" or "off" depending on whether $1 is true (0) or false
# (nonzero).
function _Dbg_onoff {
  typeset onoff='off.'
  (( $1 != 0 )) && onoff='on.'
  builtin echo $onoff
}

# Set $? to $1 if supplied or the saved entry value of $?.
function _Dbg_set_dol_q {
  return ${1:-$_Dbg_debugged_exit_code}
}

# Split $2 using $1 as the split character.  We accomplish this by
# temporarily resetting the variable IFS (input field separator).
#
# Example:
# typeset -a a=($(_Dbg_split ':' "file:line"))
# a[0] will have file and a{1] will have line.

function _Dbg_split {
  typeset old_IFS=$IFS
  typeset new_ifs=${1:-' '}
  shift
  typeset -r text="$*"
  typeset -a array
  IFS="$new_ifs"
  array=( $text )
  echo ${array[@]}
  IFS=$old_IFS
}

# _get_function echoes a list of all of the functions.
# if $1 is nonzero, system functions, i.e. those whose name starts with
# an underscore (_), are included in the search.
# FIXME add parameter search pattern.
_Dbg_get_functions() {
    typeset -i include_system=${1:-0}
    typeset    pat=${2:-.*}
    typeset -a fns_a
    fns_a=( $(declare -F) )
    typeset -a ret_fns=()
    typeset -i i
    typeset -i invert=0;

    if [[ $pat == !* ]] ; then
	# Remove leading !
	pat=#{$pat#!}
	invert=1
    fi

    # Iterate skipping over consecutive single tokens "declare" and "-F"
    for (( i=2; (( i < ${#fns_a[@]} )) ; i += 3 )) ; do
	typeset fn="${fns_a[$i]}"
	[[ $fn == _* ]] && (( ! include_system )) && continue
	if [[ $fn =~ $pat ]] ; then
	     [[ $invert == 0 ]] && ret_fns[${#ret_fns[@]}]=$fn
	else
	     [[ $invert != 0 ]] && ret_fns[${#ret_fns[@]}]=$fn
	fi

    done
    echo ${ret_fns[@]}
}

# _Dbg_is_function returns 0 if $1 is a defined function or nonzero otherwise.
# if $2 is nonzero, system functions, i.e. those whose name starts with
# an underscore (_), are included in the search.
_Dbg_is_function() {
    (( 0 == $# )) && return 1
    typeset needed_fn=$1
    typeset -i include_system=${2:-0}
    [[ ${needed_fn:0:1} == '_' ]] && ((!include_system)) && {
	return 1
    }
    declare -F $needed_fn >/dev/null 2>&1
    return $?
}

# Return 0 if set -x tracing is on
_Dbg_is_traced() {
    # Is "x" in set options?
    if [[ $- == *x* ]] ; then
	return 0
    else
	return 1
    fi
}

# Common routine for setup of commands that take a single
# linespec argument. We assume the following variables
# which we store into:
#  filename, line_number, full_filename

function _Dbg_linespec_setup {
  typeset linespec=${1:-''}
  if [[ -z $linespec ]] ; then
    _Dbg_errmsg "Invalid line specification, null given"
  fi
  typeset -a word
  eval "word=($(_Dbg_parse_linespec $linespec))"
  if [[ ${#word[@]} == 0 ]] ; then
    _Dbg_errmsg "Invalid line specification: $linespec"
    return
  fi

  filename="${word[2]}"
  typeset -ri is_function=${word[1]}
  line_number=${word[0]}
  full_filename=$(_Dbg_is_file "$filename")

  if (( is_function )) ; then
      if [[ -z "$full_filename" ]] ; then
	  _Dbg_readin "$filename"
	  full_filename=$(_Dbg_is_file "$filename")
      fi
  fi
}

# Parse linespec in $1 which should be one of
#   int
#   file:line
#   function-num
# Return triple (line,  is-function?, filename,)
# We return the filename last since that can have embedded blanks.
function _Dbg_parse_linespec {
  typeset linespec=$1
  eval "$_seteglob"
  case "$linespec" in

    # line number only - use _Dbg_frame_last_filename for filename
    $int_pat )
      echo "$linespec 0 \"$_Dbg_frame_last_filename\""
      ;;

    # file:line
    [^:][^:]*[:]$int_pat )
      # Split the POSIX way
      typeset line_word=${linespec##*:}
      typeset file_word=${linespec%${line_word}}
      file_word=${file_word%?}
      echo "$line_word 0 \"$file_word\""
      ;;

    # Function name or error
    * )
      if _Dbg_is_function $linespec $_Dbg_set_debug ; then
	local -a word=( $(declare -F $linespec) )
	if [[ 0 == $? && ${#word[@]} > 2 ]]; then
	  builtin echo "${word[1]} 1 ${word[2]}"
	else
	  builtin echo ''
	fi
      else
	builtin echo ''
      fi
      ;;
   esac
}

# usage _Dbg_set_ftrace [-u] funcname [funcname...]
# Sets or unsets a function for stopping by setting
# the -t or +t property to the function declaration.
#
function _Dbg_set_ftrace {
  typeset opt=-t tmsg="enabled" func
  if [[ $1 == -u ]]; then
	opt=+t
	tmsg="disabled"
	shift
  fi
  for func; do
	  declare -f $opt $func
	  # _Dbg_msg "Tracing $tmsg for function $func"
  done
}

# Adapted from
# https://stackoverflow.com/questions/14525296/bash-check-if-variable-is-array
function _Dbg_is_readonly_array() {
    # no argument passed
    if [[ $# -ne 1 ]]; then
	return 1
    fi
    typeset var=$1
    # use a variable to avoid having to escape spaces
    regex="^declare -ar ${var}(=|$)"
    if [[ $(declare -p "$var" 2> /dev/null) =~ $regex ]]; then
	return 0
    else
	return 1
    fi
}