#!/bin/bash

######################################################################

#

#   tcar_getConfigLines.sh -- This function standardizes the way

#   configuration lines are retrieved form configuration files. As

#   arguments, the configuration file absolute path, the configuration

#   section name, and the configuration option name must be provided.

#

#   Written by: 

#   * Alain Reguera Delgado <al@centos.org.cu>, 2009-2013

#     Key fingerprint = D67D 0F82 4CBD 90BC 6421  DF28 7CCE 757C 17CA 3951

#

# Copyright (C) 2009-2013 The CentOS Project

#

# 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, write to the Free Software

# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

#

######################################################################

function tcar_getConfigLines {

    # Initialize absolute path to configuration file.

    local CONFIGURATION_FILE="${1}"

    # Initialize configuration section name where the variable value

    # we want to to retrieve is set in.

    local CONFIGURATION_SECTION="${2}"

    # Initialize variable name we want to retrieve value from.

    local CONFIGURATION_OPTION="${3}"

    # Verify configuration variable name. When no variable name is

    # provided print all configuration lines that can be considered as

    # well-formed paths. Be sure configuration variable name starts

    # just at the beginning of the line.

    if [[ ! ${CONFIGURATION_OPTION} =~ '^[[:alnum:]_./-]+$' ]];then

        CONFIGURATION_OPTION='[[:alnum:]_./-]+[[:space:]]*='

    fi

    # Retrieve configuration lines from configuration file. Don't sort

    # the value of this value so as to preserve the order given in the

    # configuration file. This is important because configuration

    # files are being used for setting render-from priorities.

    local CONFIGURATION_LINES=$(cat ${CONFIGURATION_FILE} \

        | egrep -v '^#' \

        | egrep -v '^[[:space:]]*$' \

        | sed -r -n "/^\[${CONFIGURATION_SECTION}\][[:space:]]*$/,/^\[/p" \

        | egrep -v '^\[' \

        | egrep "^${CONFIGURATION_OPTION}")

    # Output value related to variable name.

    echo "${CONFIGURATION_LINES}"

}