support XS calc_mdt, improved BEGIN block

[gitmo/Class-C3.git] / lib / Class / C3.pm

diff --git a/lib/Class/C3.pm b/lib/Class/C3.pm
index 372825a..45babf4 100644 (file)
--- a/lib/Class/C3.pm
+++ b/lib/Class/C3.pm
@@ -4,20 +4,22 @@ package Class::C3;
 use strict;
 use warnings;
 
-our $VERSION = '0.15_01';
+our $VERSION = '0.15_05';
 
 our $C3_IN_CORE;
+our $C3_XS;
 
 BEGIN {
-    eval "require mro"; # XXX in the future, this should be a version check
-    if($@) {
-        die $@ if $@ !~ /locate/;
-#        eval "require Class::C3::XS";
-#        if($@) {
-#            die $@ if $@ !~ /locate/;
-            eval "require Algorithm::C3; require Class::C3::next";
-            die $@ if $@;
-#        }
+    if($^V < 5.009005) {
+        eval "require Class::C3::XS";
+        if(my $error = $@) {
+            die $error if $error !~ /\blocate\b/;
+            require Algorithm::C3;
+            require Class::C3::next;
+        }
+        else {
+            $C3_XS = 1;
+        }
     }
     else {
         $C3_IN_CORE = 1;
@@ -112,7 +114,7 @@ sub _calculate_method_dispatch_table {
     no strict 'refs';
     my @MRO = calculateMRO($class, $merge_cache);
     $MRO{$class} = { MRO => \@MRO };
-    my $has_overload_fallback = 0;
+    my $has_overload_fallback;
     my %methods;
     # NOTE: 
     # we do @MRO[1 .. $#MRO] here because it
@@ -123,7 +125,7 @@ sub _calculate_method_dispatch_table {
         # have use "fallback", then we want to
         # grab that value 
         $has_overload_fallback = ${"${local}::()"} 
-            if defined ${"${local}::()"};
+            if !defined $has_overload_fallback && defined ${"${local}::()"};
         foreach my $method (grep { defined &{"${local}::$_"} } keys %{"${local}::"}) {
             # skip if already overriden in local class
             next unless !defined *{"${class}::$method"}{CODE};
@@ -150,8 +152,13 @@ sub _apply_method_dispatch_table {
     my $class = shift;
     no strict 'refs';
     ${"${class}::()"} = $MRO{$class}->{has_overload_fallback}
-        if $MRO{$class}->{has_overload_fallback};
+        if !defined &{"${class}::()"}
+           && defined $MRO{$class}->{has_overload_fallback};
     foreach my $method (keys %{$MRO{$class}->{methods}}) {
+        if ( $method =~ /^\(/ ) {
+            my $orig = $MRO{$class}->{methods}->{$method}->{orig};
+            ${"${class}::$method"} = $$orig if defined $$orig;
+        }
         *{"${class}::$method"} = $MRO{$class}->{methods}->{$method}->{code};
     }    
 }
@@ -160,7 +167,7 @@ sub _remove_method_dispatch_tables {
     return if $C3_IN_CORE;
     foreach my $class (keys %MRO) {
         _remove_method_dispatch_table($class);
-    }       
+    }
 }
 
 sub _remove_method_dispatch_table {
@@ -172,20 +179,31 @@ sub _remove_method_dispatch_table {
         delete ${"${class}::"}{$method}
             if defined *{"${class}::${method}"}{CODE} && 
                (*{"${class}::${method}"}{CODE} eq $MRO{$class}->{methods}->{$method}->{code});       
-    }   
+    }
 }
 
 sub calculateMRO {
     my ($class, $merge_cache) = @_;
 
-    return @{mro::get_linear_isa($class)} if $C3_IN_CORE;
-
     return Algorithm::C3::merge($class, sub { 
         no strict 'refs'; 
         @{$_[0] . '::ISA'};
     }, $merge_cache);
 }
 
+sub _core_calculateMRO { @{mro::get_linear_isa($_[0])} }
+
+if($C3_IN_CORE) {
+    no warnings 'redefine';
+    *Class::C3::calculateMRO = \&_core_calculateMRO;
+}
+elsif($C3_XS) {
+    no warnings 'redefine';
+    *Class::C3::calculateMRO = \&Class::C3::XS::calculateMRO;
+    *Class::C3::_calculate_method_dispatch_table
+        = \&Class::C3::XS::_calculate_method_dispatch_table;
+}
+
 1;
 
 __END__
@@ -236,18 +254,16 @@ Class::C3 - A pragma to use the C3 method resolution order algortihm
     D->can('hello')->();          # can() also works correctly
     UNIVERSAL::can('D', 'hello'); # as does UNIVERSAL::can()
 
-=head1 SPECIAL NOTE FOR 0.15_01
+=head1 SPECIAL NOTE FOR 0.15_05
 
-To try this with the experimental perl core c3 patch,
-download a recent copy perl-current:
+To try this with the new perl core c3 support,
+download the most recent copy perl-current:
 
-http://mirrors.develooper.com/perl/APC/perl-current-snap/perl-current@30943.tar.bz2
-
-apply the enclosed c3.patch, and install this perl:
+http://mirrors.develooper.com/perl/APC/perl-current-snap/
 
 sh Configure -Dusedevel -Dprefix=/where/I/want/it -d -e && make && make test && make install
 
-then try your C3-using software against this perl + Class::C3 0.15_01.
+then try your C3-using software against this perl + Class::C3 0.15_05.
 
 =head1 DESCRIPTION
 
@@ -467,6 +483,16 @@ limitation of this module.
 
 =back
 
+=head1 COMPATIBILITY
+
+If your software requires Perl 5.9.5 or higher, you do not need L<Class::C3>, you can simple C<use mro 'c3'>, and not worry about C<initialize()>, avoid some of the above caveats, and get the best possible performance.  See L<mro> for more details.
+
+If your software is meant to work on earlier Perls, use L<Class::C3> as documented here.  L<Class::C3> will detect Perl 5.9.5+ and take advantage of the core support when available.
+
+=head1 Class::C3::XS
+
+This module will load L<Class::C3::XS> if it's installed and you are running on a Perl version older than 5.9.5.  Installing this is recommended when possible, as it results in significant performance improvements (but unlike the 5.9.5+ core support, it still has all of the same caveats as L<Class::C3>).
+
 =head1 CODE COVERAGE
 
 I use B<Devel::Cover> to test the code coverage of my tests, below is the B<Devel::Cover> report on this