# Functions for setting and substituting variables # # Copyright (C) 2012, 2014 Patrick "P. J." McDermott # # This file is part of the ProteanOS Development Kit. # # The ProteanOS Development Kit 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 3 of the # License, or (at your option) any later version. # # The ProteanOS Development Kit 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 the ProteanOS Development Kit. If not, see # . [ "x${_SUBSTVARS_SM+set}" = 'xset' ] && return 0 _SUBSTVARS_SM=1 substvars_max_depth=50 set_substvar() { local name="${1}" local value="${2}" # Convert variable name to lower case and validate. name="$(printf '%s\n' "${name}" | tr 'A-Z-' 'a-z_')" case "${name:- }" in *[!a-z0-9_]*) warn "$(get_msg 'substvar_invalid')" "${name}" return 1 ;; esac # Trim leading and trailing newline characters from value. value="$(printf '%s\n' "${value}" | sed -n ' H; # Store each input line in the hold space. ${ # At the last line of input: g; # Restore the hold space into the pattern space. s/^[\n]*//; # Remove leading newline characters. s/[\n]*$//; # Remove trailing newline characters. p; # Print the results. }; ')" # Escape single quotes in value. value="$(printf '%s\n' "${value}" | sed "s/'/'\\\\''/g")" eval "substvar_${name}='${value}'" return 0 } substvars() { local string="${1}" local depth= local lhs= local name= local rhs= local old_rhs= local value= # Logic inspired by that of dpkg's Dpkg::Substvars::substvars() # subroutine. depth=0 while :; do lhs="${string%%\$\{*}" if [ ${#lhs} -eq ${#string} ]; then # No "${" was found. break fi string="${string#*\$\{}" name="${string%%\}*}" rhs="${string#*\}}" if [ ${#rhs} -lt ${#old_rhs} ]; then # Reset the nesting counter if we've advanced the right # side of the matched space. depth=0 fi if [ ${depth} -ge ${substvars_max_depth} ]; then # Warn of possible recursion. warn "$(get_msg 'substvar_deep_nesting')" return 1 fi old_rhs="${rhs}" # Perform the substitution. name="$(printf '%s\n' "${name}" | tr 'A-Z-' 'a-z_')" value="$(eval "printf '%s\n' \"\${substvar_${name}}\"")" string="${lhs}${value}${rhs}" depth=$(($depth + 1)) done printf '%s\n' "${string}" return 0 }