#   @(#)$Id: DBD/Informix/Configuration.pm version /main/5 2000-02-10 19:36:21 $ 
#
#   Informix ESQL/C Support Routines for Informix Database Driver for Perl Version 1.00.PC1 (2000-03-03)
#
#   Portions Copyright 1999 Jonathan Leffler
#   Portions Copyright 2000 Informix Software Inc
#
#   You may distribute under the terms of either the GNU General Public
#   License or the Artistic License, as specified in the Perl README file.

#TABSTOP=4

# This file defines the following subs, which are used by both
# Makefile.PL and BugReport.
# -- find_informixdir_and_esql
# -- get_esqlc_version
# -- map_informix_lib_names

{
	package DBD::Informix::Configuration;

	require Exporter;
	@ISA = qw(Exporter);
	@EXPORT = qw(find_informixdir_and_esql get_esqlc_version map_informix_lib_names);

	$VERSION = "1.00.PC1";
	$VERSION = "0.97002" if ($VERSION =~ m%[:]VERSION[:]%);

	use strict;
	use Config;
	use DBI;

	# Locate $INFORMIXDIR and the ESQL/C compiler
	sub find_informixdir_and_esql
	{
		my ($NTConfiguration) = @_;
		my ($esql, $ID);
		if ($NTConfiguration)
		{
			# NT configuration
			# Tested for Config: archname='MSWin32' osname='MSWin32' osvers='4.0'
			my ($p);
			# Trying to find ESQL (and determining INFORMIXDIR too)
			foreach $p (split( /;/, $ENV{PATH}))
			{
				if( -x "$p/ESQL.EXE")
				{
					# HUMS: \\ needed, because string goes into Makefile (via postamble)
					$esql="$p\\ESQL.EXE"; 
					# HUMS: \\ necessary because string comes from ENV
					$p  =~ s/\\BIN//i;
					$ID=$p;
					last;
				}
			}
			&did_not_read('No executable ESQL/C compiler found in $PATH')
				unless defined $esql;
			print "Using INFORMIXDIR=$ID and ESQL/C compiler $esql\n";
		}
		else
		{
			# Unix configuration
			$ID = $ENV{INFORMIXDIR};
			&did_not_read('$INFORMIXDIR is not set') unless ($ID);
			$esql = $ENV{ESQL};
			$esql = "esql" unless $esql;
			if ($esql =~ m%/%)
			{
				# ESQL/C program specified with path name
				&did_not_read("No executable ESQL/C compiler $esql")
					unless (-x $esql);
			}
			else
			{
				# ESQL/C program specified without any path name
				&did_not_read("No executable ESQL/C compiler $ID/bin/$esql")
					unless (-x "$ID/bin/$esql");
			}
			&did_not_read('$INFORMIXDIR/bin is not in $PATH')
				unless ($ENV{PATH} =~ m%:$ID/bin:% ||
						$ENV{PATH} =~ m%^$ID/bin:% ||
						$ENV{PATH} =~ m%:$ID/bin$%);
		}
		return $ID, $esql;
	}

	# --- Find out which version of Informix ESQL/C by running 'esql -V'
	# NB: Argument should be name of esql program which can be executed.
	#     The checks for Unix in find_informixdir_and_esql should be OK.
	#     Allow for version 10.00 and later -- still hypothetical but...
	sub get_esqlc_version
	{
		my ($esql) = @_;
		my ($infv, $vers);

		open(ESQL, "$esql -V|") || die;
		die "Failed to read anything from 'esql -V'\n"
			unless defined ($infv = <ESQL>);
		# Read the rest of the input (1 line) to avoid Broken Pipe messages
		while(<ESQL>) { }
		close ESQL;

		chomp($infv);
		$infv =~ s/\s+$//;	# Delete trailing white space
		$infv =~ s/\s+/ /g;	# Replace white space with single blanks
		$vers = $infv;
		$vers =~ s/INFORMIX.* Version (\d+[.]\d+).*/$1/;
		die "Unexpected message from esql script -- $infv\n"
			unless ($vers =~ /\d+[.]\d+/);
		$vers =~ s/^([0-9])\./$1/;

		return $infv, $vers;
	}

	# If DBD_INFORMIX_RELOCATABLE_INFORMIXDIR is set, then leave Informix
	# library file specifications alone.  If it is not set, then hard-code the
	# Informix library path names.  This will simplify life on most platforms.
	# It also, more or less, follows the ideas espoused in 'Why LD_LIBRARY_PATH
	# is bad', by David Barr (http://www.visi.com/~barr/ldpath.html).
	#
	# This gets tricky.  We need to remove any library path arguments which
	# refer to $INFORMIXDIR, such as -L$INFORMIXDIR/lib, and map any references
	# to -lixlib into $INFORMIXDIR/lib/libixlib.so (unless that's libixlib.sl,
	# etc).  Further, you can write -L $INFORMIXDIR/lib and -l ixlib, so we
	# should be prepared to handle adjacent pairs of arguments on occasion.
	# NB: this version does not support spaces between -[lL] and the argument.
	# And heaven help us on systems where we are not using this script (eg
	# AIX 4.2).  Note, too, that this assumes you will use shared libraries
	# if they exist.  It needs to be rigged to avoid doing the mapping if
	# shared libaries are not wanted at all.

	sub map_informix_lib_names
	{
		my @i_libs = @_;
		my @o_libs = ();
		my $ixd = $ENV{INFORMIXDIR};
		my @ixlibdirs = ();
		my $arg;

		for $arg (@i_libs)
		{
			if ($arg =~ m%^-L$ixd/%o)
			{
				push @o_libs, $arg;
				$arg =~ s%-L%%;
				push @ixlibdirs, $arg;
			}
			elsif ($arg =~ m%^-l.+%o)
			{
				push @o_libs, &map_library($arg, @ixlibdirs);
			}
			else
			{
				push @o_libs, $arg;
			}
		}

		@o_libs;
	}

	# Non-exported sub to map a single library name if found in one
	# of the (Informix) library directories
	sub map_library
	{
		my ($lib, @libdirs) = @_;
		my ($dir, $ext, $path);
		my $ar_ext = $Config{lib_ext};	# Regular, static libraries
		my $dl_ext = ".$Config{dlext}";	# Shared, dynamic libraries
		my $stub = $lib;
		$stub =~ s/-l//;
		$stub = "lib$stub";
		for $dir (@libdirs)
		{
			for $ext ($dl_ext, $ar_ext)
			{
				$path = "$dir/$stub$ext";
				if (-f $path)
				{
					print "\t$0: map $lib to $path\n" if $ENV{DBD_INFORMIX_DEBUG_LIBMAP};
					return $path;
				}
			}
		}
		return $lib;
	}

	# Tell the user that they did not read the README file and why
	# we think they didn't read it.
	sub did_not_read
	{
		die "\n*** You didn't read the README file!\n@_\n\n";
	}

	1;
}

__END__

=head1 NAME

DBD::Informix::Configuration - Determining your ESQL/C Configuration

=head1 SYNOPSIS

use DBD::Informix::Configuration;

=head1 DESCRIPTION

This module is used by Informix Database Driver for Perl Version 1.00.PC1 (2000-03-03) in the build and bug reporting code.
You will seldom if ever have cause to use this module directly.

=head2 Using find_informixdir_and_esql

The function find_informixdir_and_esql returns both the value of
$INFORMIXDIR and the pathname of the ESQL/C compiler executable (a
script on Unix, an executable program on Windows NT).
The parameter should be true if the search is being done on Windows
NT; it is false if it is being done on a Unix system.

	my ($ixd, $esql) = find_informix_dir_and_esql($nt);

=head2 Using get_esqlc_version

Given the pathname of the ESQL/C compiler, this function returns
the ESQL/C version number as a string (such as 9.21.UC1) and as a
pure integer (such as 921).

	my ($infversion, $vernum) = &get_esqlc_version($esqlprog);

=head1 AUTHOR

Jonathan Leffler

=cut