Add Module::Loaded to the core

Message-ID: <9310.80.127.35.68.1155478929.squirrel@webmail.xs4all.nl>

p4raw-id: //depot/perl@28706

diff --git a/MANIFEST b/MANIFEST
index 757c1b1..e01eb22 100644 (file)
--- a/MANIFEST
+++ b/MANIFEST
@@ -2050,6 +2050,8 @@ lib/Module/CoreList/bin/corelist  Module::CoreList
 lib/Module/CoreList.pm                 Module::CoreList
 lib/Module/CoreList/t/corelist.t       Module::CoreList
 lib/Module/CoreList/t/find_modules.t   Module::CoreList
+lib/Module/Loaded.pm   Module::Loaded
+lib/Module/Loaded/t/01_Module-Loaded.t Module::Loaded tests
 lib/Module/Load.pm     Module::Load
 lib/Module/Load/t/01_Module-Load.t     Module::Load tests
 lib/Module/Load/t/to_load/config_file  Module::Load tests

diff --git a/lib/Module/Loaded.pm b/lib/Module/Loaded.pm
new file mode 100644 (file)
index 0000000..6ab2676
--- /dev/null
+++ b/lib/Module/Loaded.pm
@@ -0,0 +1,144 @@
+package Module::Loaded;
+
+use strict;
+use Carp qw[carp];
+
+BEGIN { use base 'Exporter';
+        use vars qw[@EXPORT $VERSION];
+        
+        $VERSION = '0.01';
+        @EXPORT  = qw[mark_as_loaded mark_as_unloaded is_loaded];
+}
+
+=head1 NAME 
+
+Module::Loaded - mark modules as loaded or unloaded
+
+=head1 SYNOPSIS
+
+    use Module::Loaded;
+    
+    $bool = mark_as_loaded('Foo');   # Foo.pm is now marked as loaded
+    $loc  = is_loaded('Foo');        # location of Foo.pm set to the 
+                                     # loaders location
+    eval "require 'Foo'";            # is now a no-op
+
+    $bool = mark_as_unloaded('Foo'); # Foo.pm no longer marked as loaded
+    eval "require 'Foo'";            # Will try to find Foo.pm in @INC
+
+=head1 DESCRIPTION
+
+When testing applications, often you find yourself needing to provide
+functionality in your test environment that would usually be provided
+by external modules. Rather than munging the C<%INC> by hand to mark
+these external modules as loaded, so they are not attempted to be loaded
+by perl, this module offers you a very simple way to mark modules as
+loaded and/or unloaded.
+
+=head1 FUNCTIONS
+
+=head2 $bool = mark_as_loaded( PACKAGE );
+
+Marks the package as loaded to perl. C<PACKAGE> can be a bareword or
+string.
+
+If the module is already loaded, C<mark_as_loaded> will carp about
+this and tell you from where the C<PACKAGE> has been loaded already.
+
+=cut
+
+sub mark_as_loaded (*) {
+    my $pm      = shift;
+    my $file    = __PACKAGE__->_pm_to_file( $pm ) or return;
+    my $who     = [caller]->[1];
+    
+    my $where   = is_loaded( $pm );
+    if ( defined $where ) {
+        carp "'$pm' already marked as loaded ('$where')";
+    
+    } else {
+        $INC{$file} = $who;
+    }
+    
+    return 1;
+}
+
+=head2 $bool = mark_as_unloaded( PACKAGE );
+
+Marks the package as unloaded to perl, which is the exact opposite 
+of C<mark_as_loaded>. C<PACKAGE> can be a bareword or string.
+
+If the module is already unloaded, C<mark_as_unloaded> will carp about
+this and tell you the C<PACKAGE> has been unloaded already.
+
+=cut
+
+sub mark_as_unloaded (*) { 
+    my $pm      = shift;
+    my $file    = __PACKAGE__->_pm_to_file( $pm ) or return;
+
+    unless( defined is_loaded( $pm ) ) {
+        carp "'$pm' already marked as unloaded";
+
+    } else {
+        delete $INC{ $file };
+    }
+    
+    return 1;
+}
+
+=head2 $loc = is_loaded( PACKAGE );
+
+C<is_loaded> tells you if C<PACKAGE> has been marked as loaded yet.
+C<PACKAGE> can be a bareword or string.
+
+It returns falls if C<PACKAGE> has not been loaded yet and the location 
+from where it is said to be loaded on success.
+
+=cut
+
+sub is_loaded (*) { 
+    my $pm      = shift;
+    my $file    = __PACKAGE__->_pm_to_file( $pm ) or return;
+
+    return $INC{$file} if exists $INC{$file};
+    
+    return;
+}
+
+
+sub _pm_to_file {
+    my $pkg = shift;
+    my $pm  = shift or return;
+    
+    my $file = join '/', split '::', $pm;
+    $file .= '.pm';
+    
+    return $file;
+}    
+
+=head1 AUTHOR
+
+This module by
+Jos Boumans E<lt>kane@cpan.orgE<gt>.
+
+=head1 COPYRIGHT
+
+This module is
+copyright (c) 2004-2005 Jos Boumans E<lt>kane@cpan.orgE<gt>.
+All rights reserved.
+
+This library is free software;
+you may redistribute and/or modify it under the same
+terms as Perl itself.
+
+=cut
+
+# Local variables:
+# c-indentation-style: bsd
+# c-basic-offset: 4
+# indent-tabs-mode: nil
+# End:
+# vim: expandtab shiftwidth=4:
+
+1;

diff --git a/lib/Module/Loaded/t/01_Module-Loaded.t b/lib/Module/Loaded/t/01_Module-Loaded.t
new file mode 100644 (file)
index 0000000..f4c1a46
--- /dev/null
+++ b/lib/Module/Loaded/t/01_Module-Loaded.t
@@ -0,0 +1,47 @@
+use strict;
+use Test::More  'no_plan';
+
+my $Class   = 'Module::Loaded';
+my @Funcs   = qw[mark_as_loaded mark_as_unloaded is_loaded];
+my $Mod     = 'Foo::Bar'.$$;
+my $Strict  = 'strict';
+
+### load the thing
+{   use_ok( $Class );
+    can_ok( $Class, @Funcs );
+}    
+
+{   ok( !is_loaded($Mod),       "$Mod not loaded yet" );
+    ok( mark_as_loaded($Mod),   "   $Mod now marked as loaded" );
+    is( is_loaded($Mod), $0,    "   $Mod is loaded from $0" );
+    
+    my $rv = eval "require $Mod; 1";
+    ok( $rv,                    "$Mod required" );
+    ok( !$@,                    "   require did not die" );
+}
+
+### unload again
+{   ok( mark_as_unloaded($Mod), "$Mod now marked as unloaded" );
+    ok( !is_loaded($Mod),       "   $Mod now longer loaded" );
+
+    my $rv = eval "require $Mod; 1";
+    ok( !$rv,                   "$Mod require failed" );
+    ok( $@,                     "   require died" );
+    like( $@, qr/locate/,       "       with expected error" );
+}
+
+### check for an already loaded module
+{   my $where = is_loaded( $Strict );
+    ok( $where,                 "$Strict loaded" );
+    ok( mark_as_unloaded( $Strict ),
+                                "   $Strict unloaded" );
+
+    ### redefining subs, quell warnings
+    {   local $SIG{__WARN__} = sub {};
+        my $rv = eval "require $Strict; 1";
+        ok( $rv,                "$Strict loaded again" );
+    }
+    
+    is( is_loaded( $Strict ), $where, 
+                                "   $Strict is loaded" );
+}