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# Copyright (c) VIX TECHNOLOGY (AUST) LTD

#

# Module name   : JatsEnv.pm

# Module type   : Perl Module

# Compiler(s)   : Perl

# Environment(s): JATS

#

# Description   : Provide some misc environment functions

#

# Usage         : EnvImport (VarName);

#                 EnvImportOptional (VarName [, DefaultValue]);

#

#

#......................................................................#

require 5.006_001;

use strict;

use warnings;

package JatsEnv;

use JatsError;

our (@ISA, @EXPORT, @EXPORT_OK, %EXPORT_TAGS, $VERSION);

use Exporter;

$VERSION = 1.00;

@ISA = qw(Exporter);

# Symbols to autoexport (:DEFAULT tag)

@EXPORT = qw(

                EnvImport

                EnvImportOptional

            );

#-------------------------------------------------------------------------------

# Function        : EnvImport

#

# Description     : Import an environment variable into the global name space

#                   The user should have pre-declared the usage of the variable

#                   with an "our".

#

# Inputs          : Name of the environment variable to import

#

# Returns         : 1

#                   If the variable is not present then an error message is

#                   generated and the program will be terminated. The assumption

#                   is that the variable MUST be present.

#

sub EnvImport

{

    my( $EnvVar ) = @_;

    EnvImportOptional ( $EnvVar, undef );

    Error( "Environment Variable '$EnvVar' not defined." )

        unless( defined ${$main::{$EnvVar}} );

    return 1;

}

#-------------------------------------------------------------------------------

# Function        : EnvImportOptional

#

# Description     : Import an environment variable into the global name space

#                   The user should have pre-declared the usage of the variable

#                   with an "our".

#

#                   If no default value is provided and the variable does not

#                   exist in the environment, then result will be undefined

#

# Inputs          : Name of the environment variable to import

#                   Default value

#

# Returns         : 1

#

sub EnvImportOptional

{

    my( $EnvVar, $DefaultValue ) = @_;

    unless ( defined( ${$main::{$EnvVar}} ) ) {

        my $value = $ENV{ $EnvVar };

        $value = $DefaultValue unless ( defined $value );

        ${$main::{$EnvVar}} = $value;

    }

    return 1;

}

1;