1use Config;
2use File::Basename qw(&basename &dirname);
3use File::Spec;
4use Cwd;
5
6my $origdir = cwd;
7chdir dirname($0);
8my $file = basename($0, '.PL');
9$file =~ s/_(pm)$/.$1/i;
10
11my $useConfig;
12my $Config_archname;
13my $Config_version;
14my $Config_inc_version_list;
15
16# Expand the variables only if explicitly requested
17# or if a previously installed lib.pm does this, too
18# because otherwise relocating Perl becomes much harder.
19
20my $expand_config_vars = 0;
21if ($ENV{PERL_BUILD_EXPAND_CONFIG_VARS}) {
22  $expand_config_vars = 1;
23}
24elsif (exists $ENV{PERL_BUILD_EXPAND_CONFIG_VARS}) {
25  $expand_config_vars = 0;
26}
27else {
28  eval <<'HERE';
29  require lib;
30  my $lib_file = $INC{"lib.pm"};
31  open my $fh, '<', $lib_file
32    or die "Could not open file '$lib_file' for reading: $!";
33  my $ConfigRegex = qr/(?:use|require)\s+Config(?:\s+|;)/;
34  my $found_config = 0;
35  while (defined($_ = <$fh>)) {
36    # crude heuristics to check that we were using Config
37    if (/^\s*$ConfigRegex/ || /^\s*eval.*$ConfigRegex/) {
38      $found_config = 1;
39      last;
40    }
41  }
42  $expand_config_vars = $found_config ? 0 : 1;
43HERE
44  $expand_config_vars = 0 if $@;
45}
46
47if ($expand_config_vars) {
48    $useConfig = '';
49    $Config_archname = qq('$Config{archname}');
50    $Config_version  = qq('$Config{version}');
51    my @Config_inc_version_list =
52	reverse split / /, $Config{inc_version_list};
53    $Config_inc_version_list =
54	@Config_inc_version_list ?
55	    qq(qw(@Config_inc_version_list)) : q(());
56} else {
57    $useConfig = 'use Config;';
58    $Config_archname = q($Config{archname});
59    $Config_version  = q($Config{version});
60    $Config_inc_version_list =
61	      q(reverse split / /, $Config{inc_version_list});
62}
63
64open OUT,'>', $file or die "Can't create $file: $!";
65
66print "Extracting $file (with variable substitutions)\n";
67
68# In this section, perl variables will be expanded during extraction.
69# You can use $Config{...} to use Configure variables.
70
71print OUT <<"!GROK!THIS!";
72package lib;
73
74# THIS FILE IS AUTOMATICALLY GENERATED FROM lib_pm.PL.
75# ANY CHANGES TO THIS FILE WILL BE OVERWRITTEN BY THE NEXT PERL BUILD.
76
77$useConfig
78
79use strict;
80
81my \$archname         = $Config_archname;
82my \$version          = $Config_version;
83my \@inc_version_list = $Config_inc_version_list;
84
85!GROK!THIS!
86print OUT <<'!NO!SUBS!';
87
88our @ORIG_INC = @INC;	# take a handy copy of 'original' value
89our $VERSION = '0.65';
90
91sub import {
92    shift;
93
94    my %names;
95    foreach (reverse @_) {
96	my $path = $_;		# we'll be modifying it, so break the alias
97	if ($path eq '') {
98	    require Carp;
99	    Carp::carp("Empty compile time value given to use lib");
100	}
101
102	if ($path !~ /\.par$/i && -e $path && ! -d _) {
103	    require Carp;
104	    Carp::carp("Parameter to use lib must be directory, not file");
105	}
106	unshift(@INC, $path);
107	# Add any previous version directories we found at configure time
108	foreach my $incver (@inc_version_list)
109	{
110	    my $dir = "$path/$incver";
111	    unshift(@INC, $dir) if -d $dir;
112	}
113	# Put a corresponding archlib directory in front of $path if it
114	# looks like $path has an archlib directory below it.
115	my($arch_auto_dir, $arch_dir, $version_dir, $version_arch_dir)
116	    = _get_dirs($path);
117	unshift(@INC, $arch_dir)         if -d $arch_auto_dir;
118	unshift(@INC, $version_dir)      if -d $version_dir;
119	unshift(@INC, $version_arch_dir) if -d $version_arch_dir;
120    }
121
122    # remove trailing duplicates
123    @INC = grep { ++$names{$_} == 1 } @INC;
124    return;
125}
126
127
128sub unimport {
129    shift;
130
131    my %names;
132    foreach my $path (@_) {
133	my($arch_auto_dir, $arch_dir, $version_dir, $version_arch_dir)
134	    = _get_dirs($path);
135	++$names{$path};
136	++$names{$arch_dir}         if -d $arch_auto_dir;
137	++$names{$version_dir}      if -d $version_dir;
138	++$names{$version_arch_dir} if -d $version_arch_dir;
139    }
140
141    # Remove ALL instances of each named directory.
142    @INC = grep { !exists $names{$_} } @INC;
143    return;
144}
145
146sub _get_dirs {
147    my($dir) = @_;
148    my($arch_auto_dir, $arch_dir, $version_dir, $version_arch_dir);
149
150    $arch_auto_dir    = "$dir/$archname/auto";
151    $arch_dir         = "$dir/$archname";
152    $version_dir      = "$dir/$version";
153    $version_arch_dir = "$dir/$version/$archname";
154
155    return($arch_auto_dir, $arch_dir, $version_dir, $version_arch_dir);
156}
157
1581;
159__END__
160
161=head1 NAME
162
163lib - manipulate @INC at compile time
164
165=head1 SYNOPSIS
166
167    use lib LIST;
168
169    no lib LIST;
170
171=head1 DESCRIPTION
172
173This is a small simple module which simplifies the manipulation of @INC
174at compile time.
175
176It is typically used to add extra directories to perl's search path so
177that later C<use> or C<require> statements will find modules which are
178not located on perl's default search path.
179
180=head2 Adding directories to @INC
181
182The parameters to C<use lib> are added to the start of the perl search
183path. Saying
184
185    use lib LIST;
186
187is I<almost> the same as saying
188
189    BEGIN { unshift(@INC, LIST) }
190
191For each directory in LIST (called $dir here) the lib module also
192checks to see if a directory called $dir/$archname/auto exists.
193If so the $dir/$archname directory is assumed to be a corresponding
194architecture specific directory and is added to @INC in front of $dir.
195lib.pm also checks if directories called $dir/$version and $dir/$version/$archname
196exist and adds these directories to @INC.
197
198The current value of C<$archname> can be found with this command:
199
200    perl -V:archname
201
202The corresponding command to get the current value of C<$version> is:
203
204    perl -V:version
205
206To avoid memory leaks, all trailing duplicate entries in @INC are
207removed.
208
209=head2 Deleting directories from @INC
210
211You should normally only add directories to @INC.  If you need to
212delete directories from @INC take care to only delete those which you
213added yourself or which you are certain are not needed by other modules
214in your script.  Other modules may have added directories which they
215need for correct operation.
216
217The C<no lib> statement deletes all instances of each named directory
218from @INC.
219
220For each directory in LIST (called $dir here) the lib module also
221checks to see if a directory called $dir/$archname/auto exists.
222If so the $dir/$archname directory is assumed to be a corresponding
223architecture specific directory and is also deleted from @INC. lib.pm also
224checks if directories called $dir/$version and $dir/$version/$archname
225exist and deletes these directories from @INC.
226
227=head2 Restoring original @INC
228
229When the lib module is first loaded it records the current value of @INC
230in an array C<@lib::ORIG_INC>. To restore @INC to that value you
231can say
232
233    @INC = @lib::ORIG_INC;
234
235=head1 CAVEATS
236
237In order to keep lib.pm small and simple, it only works with Unix
238filepaths.  This doesn't mean it only works on Unix, but non-Unix
239users must first translate their file paths to Unix conventions.
240
241    # VMS users wanting to put [.stuff.moo] into
242    # their @INC would write
243    use lib 'stuff/moo';
244
245=head1 NOTES
246
247In the future, this module will likely use File::Spec for determining
248paths, as it does now for Mac OS (where Unix-style or Mac-style paths
249work, and Unix-style paths are converted properly to Mac-style paths
250before being added to @INC).
251
252If you try to add a file to @INC as follows:
253
254  use lib 'this_is_a_file.txt';
255
256C<lib> will warn about this. The sole exceptions are files with the
257C<.par> extension which are intended to be used as libraries.
258
259=head1 SEE ALSO
260
261FindBin - optional module which deals with paths relative to the source file.
262
263PAR - optional module which can treat C<.par> files as Perl libraries.
264
265=head1 AUTHOR
266
267Tim Bunce, 2nd June 1995.
268
269C<lib> is maintained by the perl5-porters. Please direct
270any questions to the canonical mailing list. Anything that
271is applicable to the CPAN release can be sent to its maintainer,
272though.
273
274Maintainer: The Perl5-Porters <perl5-porters@perl.org>
275
276Maintainer of the CPAN release: Steffen Mueller <smueller@cpan.org>
277
278=head1 COPYRIGHT AND LICENSE
279
280This package has been part of the perl core since perl 5.001.
281It has been released separately to CPAN so older installations
282can benefit from bug fixes.
283
284This package has the same copyright and license as the perl core.
285
286=cut
287!NO!SUBS!
288
289close OUT or die "Can't close $file: $!";
290chdir $origdir;
291