X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FClass%2FC3.pm;h=372825a0b9eb4a9692f6c03f43a472c3b7a58722;hb=663e8dcc21aa933c6210e12b845b4a23bf209cd0;hp=3055c179d4002a8d9012ba25fdeed44330aeedcc;hpb=f7facd7b73c20ba048f0f6c0baea399ba8db10ed;p=gitmo%2FClass-C3.git diff --git a/lib/Class/C3.pm b/lib/Class/C3.pm index 3055c17..372825a 100644 --- a/lib/Class/C3.pm +++ b/lib/Class/C3.pm @@ -4,9 +4,25 @@ package Class::C3; use strict; use warnings; -use Scalar::Util 'blessed'; - -our $VERSION = '0.07'; +our $VERSION = '0.15_01'; + +our $C3_IN_CORE; + +BEGIN { + eval "require mro"; # XXX in the future, this should be a version check + if($@) { + die $@ if $@ !~ /locate/; +# eval "require Class::C3::XS"; +# if($@) { +# die $@ if $@ !~ /locate/; + eval "require Algorithm::C3; require Class::C3::next"; + die $@ if $@; +# } + } + else { + $C3_IN_CORE = 1; + } +} # this is our global stash of both # MRO's and method dispatch tables @@ -28,12 +44,18 @@ our %MRO; 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}; @@ -41,50 +63,54 @@ sub import { ## initializers -# NOTE: -# this will not run under the following -# conditions: -# - mod_perl -# - require Class::C3; -# - eval "use Class::C3" -# in all those cases, you need to call -# the initialize() function manually -INIT { initialize() } - sub initialize { + %next::METHOD_CACHE = (); # why bother if we don't have anything ... return unless keys %MRO; - _calculate_method_dispatch_tables(); - _apply_method_dispatch_tables(); - %next::METHOD_CACHE = (); + 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(); + $_initialized = 1; + } } sub uninitialize { # why bother if we don't have anything ... - return unless keys %MRO; - _remove_method_dispatch_tables(); %next::METHOD_CACHE = (); + return unless keys %MRO; + if($C3_IN_CORE) { + mro::set_mro($_, 'dfs') for keys %MRO; + } + else { + _remove_method_dispatch_tables(); + $_initialized = 0; + } } -sub reinitialize { - uninitialize(); - # clean up the %MRO before we re-initialize - $MRO{$_} = undef foreach keys %MRO; - initialize(); -} +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); + _calculate_method_dispatch_table($class, \%merge_cache); } } sub _calculate_method_dispatch_table { - my $class = shift; + return if $C3_IN_CORE; + my ($class, $merge_cache) = @_; no strict 'refs'; - my @MRO = calculateMRO($class); + my @MRO = calculateMRO($class, $merge_cache); $MRO{$class} = { MRO => \@MRO }; my $has_overload_fallback = 0; my %methods; @@ -113,12 +139,14 @@ sub _calculate_method_dispatch_table { } 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} @@ -129,114 +157,33 @@ sub _apply_method_dispatch_table { } 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}; + delete ${"${class}::"}{$method} + if defined *{"${class}::${method}"}{CODE} && + (*{"${class}::${method}"}{CODE} eq $MRO{$class}->{methods}->{$method}->{code}); } } -## functions for calculating C3 MRO - -# this function is a perl-port of the -# python code on this page: -# http://www.python.org/2.3/mro.html -sub _merge { - my (@seqs) = @_; - my $class_being_merged = $seqs[0]->[0]; - my @res; - while (1) { - # remove all empty seqences - my @nonemptyseqs = (map { (@{$_} ? $_ : ()) } @seqs); - # return the list if we have no more no-empty sequences - return @res if not @nonemptyseqs; - my $reject; - my $cand; # a canidate .. - foreach my $seq (@nonemptyseqs) { - $cand = $seq->[0]; # get the head of the list - my $nothead; - foreach my $sub_seq (@nonemptyseqs) { - # XXX - this is instead of the python "in" - my %in_tail = (map { $_ => 1 } @{$sub_seq}[ 1 .. $#{$sub_seq} ]); - # NOTE: - # jump out as soon as we find one matching - # there is no reason not too. However, if - # we find one, then just remove the '&& last' - $nothead++ && last if exists $in_tail{$cand}; - } - last unless $nothead; # leave the loop with our canidate ... - $reject = $cand; - $cand = undef; # otherwise, reject it ... - } - die "Inconsistent hierarchy found while merging '$class_being_merged':\n\t" . - "current merge results [\n\t\t" . (join ",\n\t\t" => @res) . "\n\t]\n\t" . - "mergeing failed on '$reject'\n" if not $cand; - push @res => $cand; - # now loop through our non-empties and pop - # off the head if it matches our canidate - foreach my $seq (@nonemptyseqs) { - shift @{$seq} if $seq->[0] eq $cand; - } - } -} - sub calculateMRO { - my ($class) = @_; - no strict 'refs'; - return _merge( - [ $class ], # the class we are linearizing - (map { [ calculateMRO($_) ] } @{"${class}::ISA"}), # the MRO of all the superclasses - [ @{"${class}::ISA"} ] # a list of all the superclasses - ); -} - -package # hide me from PAUSE - next; - -use strict; -use warnings; - -use Scalar::Util 'blessed'; - -our $VERSION = '0.04'; - -our %METHOD_CACHE; - -sub method { - my @label = (split '::', (caller(1))[3]); - my $label = pop @label; - my $caller = join '::' => @label; - my $self = $_[0]; - my $class = blessed($self) || $self; - - goto &{ $METHOD_CACHE{"$class|$caller|$label"} ||= do { - - my @MRO = Class::C3::calculateMRO($class); - - my $current; - while ($current = shift @MRO) { - last if $caller eq $current; - } + my ($class, $merge_cache) = @_; - no strict 'refs'; - my $found; - foreach my $class (@MRO) { - next if (defined $Class::C3::MRO{$class} && - defined $Class::C3::MRO{$class}{methods}{$label}); - last if (defined ($found = *{$class . '::' . $label}{CODE})); - } + return @{mro::get_linear_isa($class)} if $C3_IN_CORE; - die "No next::method '$label' found for $self" unless $found; - - $found; - } }; + return Algorithm::C3::merge($class, sub { + no strict 'refs'; + @{$_[0] . '::ISA'}; + }, $merge_cache); } 1; @@ -277,6 +224,10 @@ Class::C3 - A pragma to use the C3 method resolution order algortihm # package main; + + # initializez the C3 module + # (formerly called in INIT) + Class::C3::initialize(); print join ', ' => Class::C3::calculateMRO('Diamond_D') # prints D, B, C, A @@ -285,11 +236,23 @@ 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 + +To try this with the experimental perl core c3 patch, +download a 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: + +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. + =head1 DESCRIPTION -This is currently an experimental pragma to change Perl 5's standard method resolution order -from depth-first left-to-right (a.k.a - pre-order) to the more sophisticated C3 method resolution -order. +This is pragma to change Perl 5's standard method resolution order from depth-first left-to-right +(a.k.a - pre-order) to the more sophisticated C3 method resolution order. =head2 What is C3? @@ -319,11 +282,11 @@ the L section. =head2 How does this module work? -This module uses a technique similar to Perl 5's method caching. During the INIT phase, this module -calculates the MRO of all the classes which called C. It then gathers information from -the symbol tables of each of those classes, and builds a set of method aliases for the correct -dispatch ordering. Once all these C3-based method tables are created, it then adds the method aliases -into the local classes symbol table. +This module uses a technique similar to Perl 5's method caching. When C is +called, this module calculates the MRO of all the classes which called C. It then +gathers information from the symbol tables of each of those classes, and builds a set of method +aliases for the correct dispatch ordering. Once all these C3-based method tables are created, it +then adds the method aliases into the local classes symbol table. The end result is actually classes with pre-cached method dispatch. However, this caching does not do well if you start changing your C<@ISA> or messing with class symbol tables, so you should consider @@ -355,11 +318,34 @@ Given a C<$class> this will return an array of class names in the proper C3 meth =item B -This can be used to initalize the C3 method dispatch tables. You need to call this if you are running -under mod_perl, or in any other environment which does not run the INIT phase of the perl compiler. +This B to initalize the C3 method dispatch tables, this module B if +you do not do this. It is advised to do this as soon as possible B loading any classes which +use C3. Here is a quick code example: + + package Foo; + use Class::C3; + # ... Foo methods here + + package Bar; + use Class::C3; + use base 'Foo'; + # ... Bar methods here + + package main; + + Class::C3::initialize(); # now it is safe to use Foo and Bar + +This function used to be called automatically for you in the INIT phase of the perl compiler, but +that lead to warnings if this module was required at runtime. After discussion with my user base +(the L folks), we decided that calling this in INIT was more of an annoyance than a +convience. I apologize to anyone this causes problems for (although i would very suprised if I had +any other users other than the L folks). The simplest solution of course is to define +your own INIT method which calls this function. NOTE: -This can B be used to re-load the dispatch tables for all classes. Use C for that. + +If C detects that C has already been executed, it will L and +clear the MRO cache first. =item B @@ -368,11 +354,7 @@ style dispatch order (depth-first, left-to-right). =item B -This effectively calls C followed by C the result of which is a reloading of -B the calculated C3 dispatch tables. - -It should be noted that if you have a large class library, this could potentially be a rather costly -operation. +This is an alias for L above. =back @@ -417,15 +399,25 @@ that you cannot dispatch to a method of a different name (this is how C The next thing to keep in mind is that you will need to pass all arguments to C it can not automatically use the current C<@_>. -=head1 CAVEATS +If C cannot find a next method to re-dispatch the call to, it will throw an exception. +You can use C to see if C will succeed before you call it like so: -Let me first say, this is an experimental module, and so it should not be used for anything other -then other experimentation for the time being. + $self->next::method(@_) if $self->next::can; -That said, it is the authors intention to make this into a completely usable and production stable -module if possible. Time will tell. +Additionally, you can use C as a shortcut to only call the next method if it exists. +The previous example could be simply written as: -And now, onto the caveats. + $self->maybe::next::method(@_); + +There are some caveats about using C, see below for those. + +=head1 CAVEATS + +This module used to be labeled as I, however it has now been pretty heavily tested by +the good folks over at L and I am confident this module is perfectly usable for +whatever your needs might be. + +But there are still caveats, so here goes ... =over 4 @@ -446,33 +438,46 @@ in F for more information. =item Adding/deleting methods from class symbol tables. -This module calculates the MRO for each requested class during the INIT phase by interogatting the symbol -tables of said classes. So any symbol table manipulation which takes place after our INIT phase is run will -not be reflected in the calculated MRO. Just as with changing the C<@ISA>, you will need to call -C for any changes you make to take effect. +This module calculates the MRO for each requested class by interogatting the symbol tables of said classes. +So any symbol table manipulation which takes place after our INIT phase is run will not be reflected in +the calculated MRO. Just as with changing the C<@ISA>, you will need to call C for any +changes you make to take effect. -=back +=item Calling C from methods defined outside the class -=head1 TODO +There is an edge case when using C from within a subroutine which was created in a different +module than the one it is called from. It sounds complicated, but it really isn't. Here is an example which +will not work correctly: -=over 4 + *Foo::foo = sub { (shift)->next::method(@_) }; -=item More tests +The problem exists because the anonymous subroutine being assigned to the glob C<*Foo::foo> will show up +in the call stack as being called C<__ANON__> and not C as you might expect. Since C +uses C to find the name of the method it was called in, it will fail in this case. + +But fear not, there is a simple solution. The module C will reach into the perl internals and +assign a name to an anonymous subroutine for you. Simply do this: + + use Sub::Name 'subname'; + *Foo::foo = subname 'Foo::foo' => sub { (shift)->next::method(@_) }; -You can never have enough tests :) +and things will Just Work. Of course this is not always possible to do, but to be honest, I just can't +manage to find a workaround for it, so until someone gives me a working patch this will be a known +limitation of this module. =back =head1 CODE COVERAGE -I use B to test the code coverage of my tests, below is the B report on this module's test suite. +I use B to test the code coverage of my tests, below is the B report on this +module's test suite. ---------------------------- ------ ------ ------ ------ ------ ------ ------ File stmt bran cond sub pod time total ---------------------------- ------ ------ ------ ------ ------ ------ ------ - Class/C3.pm 99.2 93.3 66.7 96.0 100.0 92.8 96.3 + Class/C3.pm 98.3 84.4 80.0 96.2 100.0 98.4 94.4 ---------------------------- ------ ------ ------ ------ ------ ------ ------ - Total 99.2 93.3 66.7 96.0 100.0 92.8 96.3 + Total 98.3 84.4 80.0 96.2 100.0 98.4 94.4 ---------------------------- ------ ------ ------ ------ ------ ------ ------ =head1 SEE ALSO @@ -521,17 +526,34 @@ I use B to test the code coverage of my tests, below is the B +and finding many bugs and providing fixes. + +=item Thanks to Justin Guenther for making C more robust by handling +calls inside C and anon-subs. + +=item Thanks to Robert Norris for adding support for C and +C. + +=back + =head1 AUTHOR Stevan Little, Estevan@iinteractive.comE +Brandon L. Black, Eblblack@gmail.comE + =head1 COPYRIGHT AND LICENSE -Copyright 2005 by Infinity Interactive, Inc. +Copyright 2005, 2006 by Infinity Interactive, Inc. L This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself. -=cut \ No newline at end of file +=cut