use strict;
use warnings;
-our $VERSION = '0.15';
+our $VERSION = '0.15_05';
+
+our $C3_IN_CORE;
+our $C3_XS;
BEGIN {
- eval { require Class::C3::XS };
- if($@) {
- eval { require Class::C3::PurePerl };
+ if($^V < 5.009005) {
+ eval "require Class::C3::XS";
if($@) {
- die 'Could not load Class::C3::XS or Class::C3::PurePerl!';
+ die $@ if $@ !~ /locate/;
+ eval "require Algorithm::C3; require Class::C3::next";
+ die $@ if $@;
+ }
+ else {
+ $C3_XS = 1;
}
}
+ else {
+ $C3_IN_CORE = 1;
+ }
+}
+
+# this is our global stash of both
+# MRO's and method dispatch tables
+# the structure basically looks like
+# this:
+#
+# $MRO{$class} = {
+# MRO => [ <class precendence list> ],
+# methods => {
+# orig => <original location of method>,
+# code => \&<ref to original method>
+# },
+# has_overload_fallback => (1 | 0)
+# }
+#
+our %MRO;
+
+# use these for debugging ...
+sub _dump_MRO_table { %MRO }
+our $TURN_OFF_C3 = 0;
+
+# state tracking for initialize()/uninitialize()
+our $_initialized = 0;
+
+sub import {
+ my $class = caller();
+ # skip if the caller is main::
+ # since that is clearly not relevant
+ return if $class eq 'main';
+
+ return if $TURN_OFF_C3;
+ mro::set_mro($class, 'c3') if $C3_IN_CORE;
+
+ # make a note to calculate $class
+ # during INIT phase
+ $MRO{$class} = undef unless exists $MRO{$class};
+}
+
+## initializers
+
+sub initialize {
+ %next::METHOD_CACHE = ();
+ # why bother if we don't have anything ...
+ return unless keys %MRO;
+ if($C3_IN_CORE) {
+ mro::set_mro($_, 'c3') for keys %MRO;
+ }
+ else {
+ if($_initialized) {
+ uninitialize();
+ $MRO{$_} = undef foreach keys %MRO;
+ }
+ _calculate_method_dispatch_tables();
+ _apply_method_dispatch_tables();
+ $_initialized = 1;
+ }
+}
+
+sub uninitialize {
+ # why bother if we don't have anything ...
+ %next::METHOD_CACHE = ();
+ return unless keys %MRO;
+ if($C3_IN_CORE) {
+ mro::set_mro($_, 'dfs') for keys %MRO;
+ }
+ else {
+ _remove_method_dispatch_tables();
+ $_initialized = 0;
+ }
+}
+
+sub reinitialize { goto &initialize }
+
+## functions for applying C3 to classes
+
+sub _calculate_method_dispatch_tables {
+ return if $C3_IN_CORE;
+ my %merge_cache;
+ foreach my $class (keys %MRO) {
+ _calculate_method_dispatch_table($class, \%merge_cache);
+ }
+}
+
+sub _calculate_method_dispatch_table {
+ return if $C3_IN_CORE;
+ my ($class, $merge_cache) = @_;
+ no strict 'refs';
+ my @MRO = calculateMRO($class, $merge_cache);
+ $MRO{$class} = { MRO => \@MRO };
+ my $has_overload_fallback;
+ my %methods;
+ # NOTE:
+ # we do @MRO[1 .. $#MRO] here because it
+ # makes no sense to interogate the class
+ # which you are calculating for.
+ foreach my $local (@MRO[1 .. $#MRO]) {
+ # if overload has tagged this module to
+ # have use "fallback", then we want to
+ # grab that value
+ $has_overload_fallback = ${"${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};
+ $methods{$method} = {
+ orig => "${local}::$method",
+ code => \&{"${local}::$method"}
+ } unless exists $methods{$method};
+ }
+ }
+ # now stash them in our %MRO table
+ $MRO{$class}->{methods} = \%methods;
+ $MRO{$class}->{has_overload_fallback} = $has_overload_fallback;
+}
+
+sub _apply_method_dispatch_tables {
+ return if $C3_IN_CORE;
+ foreach my $class (keys %MRO) {
+ _apply_method_dispatch_table($class);
+ }
+}
+
+sub _apply_method_dispatch_table {
+ return if $C3_IN_CORE;
+ my $class = shift;
+ no strict 'refs';
+ ${"${class}::()"} = $MRO{$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};
+ }
+}
+
+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 {
+ return if $C3_IN_CORE;
+ my $class = shift;
+ no strict 'refs';
+ delete ${"${class}::"}{"()"} if $MRO{$class}->{has_overload_fallback};
+ foreach my $method (keys %{$MRO{$class}->{methods}}) {
+ delete ${"${class}::"}{$method}
+ if defined *{"${class}::${method}"}{CODE} &&
+ (*{"${class}::${method}"}{CODE} eq $MRO{$class}->{methods}->{$method}->{code});
+ }
+}
+
+sub calculateMRO {
+ my ($class, $merge_cache) = @_;
+
+ return Algorithm::C3::merge($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;
}
1;
D->can('hello')->(); # can() also works correctly
UNIVERSAL::can('D', 'hello'); # as does UNIVERSAL::can()
+=head1 SPECIAL NOTE FOR 0.15_05
+
+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/
+
+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_05.
+
=head1 DESCRIPTION
This is pragma to change Perl 5's standard method resolution order from depth-first left-to-right
=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
projects / gitmo/Class-C3.git / blobdiff