shell-call-graph.in

#!/usr/bin/env bash
#
# SPDX-FileCopyrightText: 2024 Andrew L. Moore <slewsys@gmail.com>, SlewSys Research
#
# SPDX-License-Identifier: CC0-1.0
#
# @(#) shell-call-graph
#
# SYNOPSIS
#
#     shell-call-graph SHELL-SCRIPT [...]
#
# DESCRIPTION
#
# This script generates a call graph for shell scripts on its command line that are
# assumed to be structured as follows:
#
#     #!/usr/bin/env bash
#     #
#     func1 ()
#     {
#         ...
#     }
#
#     func2 ()
#     {
#         ...
#     }
#
#     ...
#
#     funcN ()
#     {
#         ...
#     }
#
#     if test ."$0" = ."${BASH_SOURCE[0]}"; then
#         ...
#     fi
#
# In particular:
# - The keyword `function' is omitted.
# - Function declarations are on lines by themselves.
# - Function-closing curly braces (`}') are on lines by themselves.
# - An `if` statement in column 1 at the end of the file  referencing
#  `$0' serves as the script's "main" function.
# - Statements within the `if' statement are on lines by themselves.
# - The closing `fi' keyword is in column 1 as well.
#
: ${CAT_CMD:='@CAT_CMD@'}
: ${ED_CMD:='@ED_CMD@'}
: ${FILE_CMD:='@FILE_CMD@'}
: ${MKTEMP_CMD:='@MKTEMP_CMD@'}
: ${PERL_CMD:='@PERL_CMD@'}
: ${PRDG_CMD:='@PRDG_CMD@'}
: ${RM_CMD:='@RM_CMD@'}
: ${SED_CMD:='@SED_CMD@'}

is-file-type ()
{
    file=$1
    file_type=$2

    if [[ ! ."$($FILE_CMD "$file")" =~ \..*$file_type ]]; then
        echo "$file: Expected file of type: ${file_type}" >&2
        return 1
    fi
}

parse-shell-scripts ()
{
    local function_list_string=''
    local -a function_list=()
    local script=''

    for script; do
        is-file-type "$script" "shell script" || return $?
        function_list_string+=$(
            $ED_CMD -E -e 'g;^([_[:alpha:]][-+_~!@%^:./?[:alnum:]]+)\s*\(\)\s*\{?;s;;\1;p' "$script"
                             ) || return $?
    done

    mapfile -t function_list <<<"$function_list_string"

    local funcall_alternates=$(IFS='|'; echo "${function_list[*]}")
    local delim='[[:space:]()<>;|&\`]'
    local funcall_regex='.*?(^|'"${delim}"')('"${funcall_alternates}"')($|'"${delim}"')'
    local ed_script=''

    for script; do
        ed_script='g/^\s*#/d
g;^if.*$0.*;s;;_'${script##*/}'_ ()\
{;
g/^fi.*/s;;};
g;^(\S+).*\(\);s;^(\S+).*;\1;p\
s;$; { '${script}': };p\
.=\
+,/^\s*}/-w ! '${PERL_CMD}' -ne '\''while (s/'$funcall_regex'/ \1/) { print "  $2\n"; }'\'

        $ED_CMD -E -e "$ed_script" "$script" || return $?
    done
}

create-adjacency-list ()
{
    local tmpfile=$1

    local ed_script='g/^[0-9]+/-,.j\
s;( })(.*);\2\1;
g;^\s+;-ka\
?\{?-t'\''a
g;.;s;$; ;\
.,+j
,p'

    $ED_CMD -E -e "$ed_script" $tmpfile
}

if test ."$0" = ."${BASH_SOURCE[0]}"; then
    create-adjacency-list  <(parse-shell-scripts "$@") |
        $PRDG_CMD -m -r _${1##*/}_
fi