# opkbuild
# lib/control
# Functions for parsing control files.
#
# Copyright (C) 2012 Patrick "P. J." McDermott
#
# 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 of the License, 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.  If not, see <http://www.gnu.org/licenses/>.

[ -n "${_OB_CONTROL_SM}" ] && return 0
_OB_CONTROL_SM='true'

ob_use messages
ob_use locale

_OB_SUBSTVARS_MAX_DEPTH=50

OB_CONTROL_NAME=
OB_CONTROL_VALUE=

ob_parse_control()
{
	_ob_local _obpco_file _obpco_field_cb _obpco_req_fields _obpco_opt_fields \
		_obpco_check_fields _obpco_all_fields _obpco_got_fields \
		_obpco_line_nr _obpco_line _obpco_name _obpco_value

	if [ ${#} -eq 2 ]; then
		_obpco_file="${1}"
		_obpco_field_cb="${2}"
		_obpco_check_fields='false'
	elif [ ${#} -eq 4 ]; then
		_obpco_file="${1}"
		_obpco_field_cb="${2}"
		_obpco_req_fields="${3}"
		_obpco_opt_fields="${4}"
		_obpco_check_fields='true'
		_obpco_all_fields=" ${_obpco_req_fields} ${_obpco_opt_fields} "
	else
		_ob_return 125
		return ${?}
	fi

	_obpco_got_fields=' '

	_obpco_line_nr=0

	while IFS= read -r _obpco_line; do
		_obpco_line_nr=$(($_obpco_line_nr + 1))
		if [ -z "$(echo ${_obpco_line})" ]; then
			_ob_parse_control_error "${_obpco_file}" "${_obpco_line_nr}" \
				'control_empty_line'
		elif [ "${_obpco_line#\#}" != "${_obpco_line}" ]; then
			# Comment.
			:
		elif [ "${_obpco_line# }" = "${_obpco_line}" ]; then
			# "Name: Value" line.
			if [ -n "${_obpco_name}" ]; then
				OB_CONTROL_NAME="${_obpco_name}"
				OB_CONTROL_VALUE="${_obpco_value}"
				"${_obpco_field_cb}"
				if [ ${?} -ne 0 ]; then
					_ob_return 0
					return ${?}
				fi
			fi
			_obpco_name="${_obpco_line%%:*}"
			_obpco_value="${_obpco_line#*:}"
			_obpco_value="${_obpco_value# }"
			if [ -z "${_obpco_name}" \
				-o "${_obpco_name}" = "${_obpco_line}" ]; then
				# Badly formatted control field.
				_ob_parse_control_error "${_obpco_file}" "${_obpco_line_nr}" \
					'control_bad_nv'
				continue
			fi
			if ${_obpco_check_fields}; then
				if [ "${_obpco_all_fields% ${_obpco_name} *}" = \
						"${_obpco_all_fields}" ]; then
					# Unknown field.
					_ob_parse_control_error \
						"${_obpco_file}" "${_obpco_line_nr}" \
						'control_unknown_field' "${_obpco_name}"
				else
					# Remove field from list of required fields.
					_obpco_req_fields="$(echo "${_obpco_req_fields}" | \
						sed "s/${_obpco_name}//")"
				fi
			fi
			if [ "${_obpco_got_fields% ${_obpco_name} *}" != \
					"${_obpco_got_fields}" ]; then
				# Duplicate field.
				_ob_parse_control_error "${_obpco_file}" "${_obpco_line_nr}" \
					'control_duplicate_field' "${_obpco_name}"
			else
				_obpco_got_fields="${_obpco_got_fields}${_obpco_name} "
			fi
		else
			# Continuation line.
			if [ -z "${_obpco_name}" ]; then
				# Expecting a "Name: Value" line.
				_ob_parse_control_error "${_obpco_file}" "${_obpco_line_nr}" \
					'control_found_continuation'
				continue
			fi
			_obpco_value="${_obpco_value}
${_obpco_line# }"
		fi
	done <<-EOF
		$(cat "${_obpco_file}")
		EOF

	if [ -n "${_obpco_name}" ]; then
		OB_CONTROL_NAME="${_obpco_name}"
		OB_CONTROL_VALUE="${_obpco_value}"
		"${_obpco_field_cb}"
		if [ ${?} -ne 0 ]; then
			_ob_return 0
			return ${?}
		fi
	fi

	if ${_obpco_check_fields}; then
		_obpco_req_fields="${_obpco_req_fields## }"
		_obpco_req_fields="${_obpco_req_fields%% }"
		if [ -n "${_obpco_req_fields}" ]; then
			# Missing required control fields.
			_obpco_req_fields="$(echo "${_obpco_req_fields}" | \
				sed 's/  / /g' | \
				sed "s/ /$(ob_get_msg 'list_item_separator')/g")"
			_ob_parse_control_error "${_obpco_file}" '0' \
				'control_missing_fields' \
				"${_obpco_req_fields}"
		fi
	fi

	_ob_return 0
	return ${?}
}

ob_set_substvar()
{
	_ob_local _obssv_name _obssv_value

	if [ ${#} -eq 2 ]; then
		_obssv_name="${1}"
		_obssv_value="${2}"
	else
		_ob_return 125
		return ${?}
	fi

	# Convert variable name to uppercase and validate.
	_obssv_name="$(echo "${_obssv_name}" | tr 'a-z-' 'A-Z_')"
	case "${_obssv_name:- }" in
		*[!A-Z0-9_]*)
			_ob_return 125
			return ${?}
			;;
	esac

	# Trim leading and trailing whitespace from value.
	_obssv_value="$(echo "${_obssv_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, and …
		  p;              # … print the results.
		};
		')"

	# Escape single quotes in value.
	_obssv_value="$(printf '%s\n' "${_obssv_value}" | sed "s/'/'\\\\''/g")"

	eval "_OB_SUBSTVAR_${_obssv_name}='${_obssv_value}'"

	_ob_return 125
	return ${?}
}

ob_substvars()
{
	_ob_local _obsv_string _obsv_depth \
		_obsv_lhs _obsv_name _obsv_rhs _obsv_old_rhs _obsv_value

	if [ ${#} -eq 1 ]; then
		_obsv_string="${1}"
	else
		_ob_return 125
		return ${?}
	fi

	# Logic inspired by that of dpkg's Dpkg::Substvars::substvars() subroutine.

	_obsv_depth=0

	while true; do
		_obsv_lhs="${_obsv_string%%\$\{*}"
		if [ ${#_obsv_lhs} -eq ${#_obsv_string} ]; then
			# No "${" was found.
			break
		fi
		_obsv_string="${_obsv_string#*\$\{}"
		_obsv_name="${_obsv_string%%\}*}"
		_obsv_rhs="${_obsv_string#*\}}"

		if [ ${#_obsv_rhs} -lt ${#_obsv_old_rhs} ]; then
			# Reset the nesting counter if we've advanced the right side of the
			# matched space.
			_obsv_depth=0
		fi
		if [ ${_obsv_depth} -ge ${_OB_SUBSTVARS_MAX_DEPTH} ]; then
			# Warn of possible recursion.
			ob_warn "$(ob_get_msg 'substvar_deep_nesting')"
			_ob_return 1
			return ${?}
		fi
		_obsv_old_rhs="${_obsv_rhs}"

		# Perform the substitution.
		_obsv_name="$(echo "${_obsv_name}" | tr 'a-z-' 'A-Z_')"
		_obsv_value="$(eval echo \"\$\{"_OB_SUBSTVAR_${_obsv_name}"\}\")"
		_obsv_string="${_obsv_lhs}${_obsv_value}${_obsv_rhs}"
		_obsv_depth=$(($_obsv_depth + 1))
	done

	printf '%s\n' "${_obsv_string}"

	_ob_return 0
	return ${?}
}

_ob_parse_control_error()
{
	_ob_local _obpcoe_file _obpcoe_line_nr _obpcoe_msg_id \
		_obpcoe_file_info _obpcoe_orig_text_domain

	_obpcoe_file="${1}"
	_obpcoe_line_nr="${2}"
	_obpcoe_msg_id="${3}"
	shift 3

	if [ "${_obpcoe_line_nr}" -eq 0 ]; then
		_obpcoe_file_info="$(printf '%20s:' "${_obpcoe_file}")"
	else
		_obpcoe_file_info="$(printf '%20s(l%d):' "${_obpcoe_file}" \
			"${_obpcoe_line_nr}")"
	fi

	_obpcoe_orig_text_domain="$(ob_get_text_domain)"
	ob_set_text_domain "${_OB_INTERNAL_TEXT_DOMAIN}"

	ob_warn "${_obpcoe_file_info} $(ob_get_msg "${_obpcoe_msg_id}")" "${@}"

	ob_set_text_domain "${_obpcoe_orig_text_domain}"

	_ob_return 0
	return ${?}
}