X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FClass%2FMOP%2FClass.pm;h=86d6f27a41fde354079494d664d75e14ec821234;hb=8b49a47227fa5b84e4a5f02f40d9e38ed3c2a0ca;hp=766ac7388a3a6c1405395746e79dcc488728ee37;hpb=d4ba1677e8379ae3f44eba383acecb911b810ab5;p=gitmo%2FClass-MOP.git diff --git a/lib/Class/MOP/Class.pm b/lib/Class/MOP/Class.pm index 766ac73..86d6f27 100644 --- a/lib/Class/MOP/Class.pm +++ b/lib/Class/MOP/Class.pm @@ -9,61 +9,58 @@ use Class::MOP::Instance; use Class::MOP::Method::Wrapped; use Carp 'confess'; -use Scalar::Util 'blessed', 'reftype', 'weaken'; -use Sub::Name 'subname'; -use B 'svref_2object'; +use Scalar::Util 'blessed', 'weaken'; -our $VERSION = '0.23'; +our $VERSION = '0.33'; our $AUTHORITY = 'cpan:STEVAN'; use base 'Class::MOP::Module'; -# Self-introspection - -sub meta { Class::MOP::Class->initialize(blessed($_[0]) || $_[0]) } - # Creation - + sub initialize { my $class = shift; my $package_name = shift; (defined $package_name && $package_name && !blessed($package_name)) - || confess "You must pass a package name and it cannot be blessed"; - $class->construct_class_instance('package' => $package_name, @_); + || confess "You must pass a package name and it cannot be blessed"; + return Class::MOP::get_metaclass_by_name($package_name) + || $class->construct_class_instance('package' => $package_name, @_); } sub reinitialize { my $class = shift; my $package_name = shift; (defined $package_name && $package_name && !blessed($package_name)) - || confess "You must pass a package name and it cannot be blessed"; + || confess "You must pass a package name and it cannot be blessed"; Class::MOP::remove_metaclass_by_name($package_name); $class->construct_class_instance('package' => $package_name, @_); -} - -# NOTE: (meta-circularity) -# this is a special form of &construct_instance +} + +# NOTE: (meta-circularity) +# this is a special form of &construct_instance # (see below), which is used to construct class -# meta-object instances for any Class::MOP::* -# class. All other classes will use the more +# meta-object instances for any Class::MOP::* +# class. All other classes will use the more # normal &construct_instance. sub construct_class_instance { my $class = shift; my %options = @_; my $package_name = $options{'package'}; (defined $package_name && $package_name) - || confess "You must pass a package name"; + || confess "You must pass a package name"; # NOTE: - # return the metaclass if we have it cached, - # and it is still defined (it has not been - # reaped by DESTROY yet, which can happen + # return the metaclass if we have it cached, + # and it is still defined (it has not been + # reaped by DESTROY yet, which can happen # annoyingly enough during global destruction) - return Class::MOP::get_metaclass_by_name($package_name) - if Class::MOP::does_metaclass_exist($package_name); + + if (defined(my $meta = Class::MOP::get_metaclass_by_name($package_name))) { + return $meta; + } # NOTE: - # we need to deal with the possibility - # of class immutability here, and then + # we need to deal with the possibility + # of class immutability here, and then # get the name of the class appropriately $class = (blessed($class) ? ($class->is_immutable @@ -73,134 +70,155 @@ sub construct_class_instance { # now create the metaclass my $meta; - if ($class =~ /^Class::MOP::Class$/) { - no strict 'refs'; - $meta = bless { + if ($class eq 'Class::MOP::Class') { + no strict 'refs'; + $meta = bless { # inherited from Class::MOP::Package - '$!package' => $package_name, - + '$!package' => $package_name, + # NOTE: - # since the following attributes will - # actually be loaded from the symbol + # since the following attributes will + # actually be loaded from the symbol # table, and actually bypass the instance # entirely, we can just leave these things # listed here for reference, because they - # should not actually have a value associated + # should not actually have a value associated # with the slot. - '%!namespace' => \undef, + '%!namespace' => \undef, # inherited from Class::MOP::Module '$!version' => \undef, '$!authority' => \undef, # defined in Class::MOP::Class '@!superclasses' => \undef, - + '%!methods' => {}, - '%!attributes' => {}, + '%!attributes' => {}, '$!attribute_metaclass' => $options{'attribute_metaclass'} || 'Class::MOP::Attribute', '$!method_metaclass' => $options{'method_metaclass'} || 'Class::MOP::Method', '$!instance_metaclass' => $options{'instance_metaclass'} || 'Class::MOP::Instance', + + ## uber-private variables + # NOTE: + # this starts out as undef so that + # we can tell the first time the + # methods are fetched + # - SL + '$!_package_cache_flag' => undef, + '$!_meta_instance' => undef, } => $class; } else { # NOTE: # it is safe to use meta here because - # class will always be a subclass of + # class will always be a subclass of # Class::MOP::Class, which defines meta $meta = $class->meta->construct_instance(%options) } - + # and check the metaclass compatibility - $meta->check_metaclass_compatability(); - + $meta->check_metaclass_compatability(); + Class::MOP::store_metaclass_by_name($package_name, $meta); - + # NOTE: # we need to weaken any anon classes # so that they can call DESTROY properly Class::MOP::weaken_metaclass($package_name) if $meta->is_anon_class; - - $meta; -} - + + $meta; +} + +sub reset_package_cache_flag { (shift)->{'$!_package_cache_flag'} = undef } +sub update_package_cache_flag { + my $self = shift; + # NOTE: + # we can manually update the cache number + # since we are actually adding the method + # to our cache as well. This avoids us + # having to regenerate the method_map. + # - SL + $self->{'$!_package_cache_flag'} = Class::MOP::check_package_cache_flag($self->name); +} + sub check_metaclass_compatability { my $self = shift; # this is always okay ... - return if blessed($self) eq 'Class::MOP::Class' && + return if blessed($self) eq 'Class::MOP::Class' && $self->instance_metaclass eq 'Class::MOP::Instance'; - my @class_list = $self->class_precedence_list; + my @class_list = $self->linearized_isa; shift @class_list; # shift off $self->name - foreach my $class_name (@class_list) { + foreach my $class_name (@class_list) { my $meta = Class::MOP::get_metaclass_by_name($class_name) || next; - + # NOTE: - # we need to deal with the possibility - # of class immutability here, and then - # get the name of the class appropriately + # we need to deal with the possibility + # of class immutability here, and then + # get the name of the class appropriately my $meta_type = ($meta->is_immutable ? $meta->get_mutable_metaclass_name() - : blessed($meta)); - + : blessed($meta)); + ($self->isa($meta_type)) - || confess $self->name . "->meta => (" . (blessed($self)) . ")" . - " is not compatible with the " . + || confess $self->name . "->meta => (" . (blessed($self)) . ")" . + " is not compatible with the " . $class_name . "->meta => (" . ($meta_type) . ")"; # NOTE: # we also need to check that instance metaclasses # are compatabile in the same the class. ($self->instance_metaclass->isa($meta->instance_metaclass)) - || confess $self->name . "->meta => (" . ($self->instance_metaclass) . ")" . - " is not compatible with the " . - $class_name . "->meta => (" . ($meta->instance_metaclass) . ")"; - } -} + || confess $self->name . "->meta => (" . ($self->instance_metaclass) . ")" . + " is not compatible with the " . + $class_name . "->meta => (" . ($meta->instance_metaclass) . ")"; + } +} ## ANON classes { # NOTE: - # this should be sufficient, if you have a - # use case where it is not, write a test and + # this should be sufficient, if you have a + # use case where it is not, write a test and # I will change it. my $ANON_CLASS_SERIAL = 0; - + # NOTE: # we need a sufficiently annoying prefix - # this should suffice for now, this is - # used in a couple of places below, so + # this should suffice for now, this is + # used in a couple of places below, so # need to put it up here for now. - my $ANON_CLASS_PREFIX = 'Class::MOP::Class::__ANON__::SERIAL::'; + my $ANON_CLASS_PREFIX = 'Class::MOP::Class::__ANON__::SERIAL::'; sub is_anon_class { my $self = shift; no warnings 'uninitialized'; - $self->name =~ /^$ANON_CLASS_PREFIX/ ? 1 : 0; + $self->name =~ /^$ANON_CLASS_PREFIX/ ? 1 : 0; } sub create_anon_class { - my ($class, %options) = @_; + my ($class, %options) = @_; my $package_name = $ANON_CLASS_PREFIX . ++$ANON_CLASS_SERIAL; return $class->create($package_name, %options); - } + } # NOTE: - # this will only get called for - # anon-classes, all other calls - # are assumed to occur during + # this will only get called for + # anon-classes, all other calls + # are assumed to occur during # global destruction and so don't # really need to be handled explicitly sub DESTROY { my $self = shift; - no warnings 'uninitialized'; + no warnings 'uninitialized'; return unless $self->name =~ /^$ANON_CLASS_PREFIX/; my ($serial_id) = ($self->name =~ /^$ANON_CLASS_PREFIX(\d+)/); - no strict 'refs'; + no strict 'refs'; foreach my $key (keys %{$ANON_CLASS_PREFIX . $serial_id}) { delete ${$ANON_CLASS_PREFIX . $serial_id}{$key}; } - delete ${'main::' . $ANON_CLASS_PREFIX}{$serial_id . '::'}; + delete ${'main::' . $ANON_CLASS_PREFIX}{$serial_id . '::'}; } } @@ -210,35 +228,47 @@ sub check_metaclass_compatability { sub create { my $class = shift; my $package_name = shift; - + (defined $package_name && $package_name) || confess "You must pass a package name"; (scalar @_ % 2 == 0) - || confess "You much pass all parameters as name => value pairs " . + || confess "You much pass all parameters as name => value pairs " . "(I found an uneven number of params in \@_)"; my (%options) = @_; + (ref $options{superclasses} eq 'ARRAY') + || confess "You must pass an ARRAY ref of superclasses" + if exists $options{superclasses}; + + (ref $options{attributes} eq 'ARRAY') + || confess "You must pass an ARRAY ref of attributes" + if exists $options{attributes}; + + (ref $options{methods} eq 'HASH') + || confess "You must pass an HASH ref of methods" + if exists $options{methods}; + my $code = "package $package_name;"; - $code .= "\$$package_name\:\:VERSION = '" . $options{version} . "';" + $code .= "\$$package_name\:\:VERSION = '" . $options{version} . "';" if exists $options{version}; - $code .= "\$$package_name\:\:AUTHORITY = '" . $options{authority} . "';" - if exists $options{authority}; - + $code .= "\$$package_name\:\:AUTHORITY = '" . $options{authority} . "';" + if exists $options{authority}; + eval $code; - confess "creation of $package_name failed : $@" if $@; - + confess "creation of $package_name failed : $@" if $@; + my $meta = $class->initialize($package_name); - - $meta->add_method('meta' => sub { + + $meta->add_method('meta' => sub { $class->initialize(blessed($_[0]) || $_[0]); }); - + $meta->superclasses(@{$options{superclasses}}) if exists $options{superclasses}; # NOTE: - # process attributes first, so that they can + # process attributes first, so that they can # install accessors, but locally defined methods # can then overwrite them. It is maybe a little odd, but # I think this should be the order of things. @@ -246,19 +276,19 @@ sub create { foreach my $attr (@{$options{attributes}}) { $meta->add_attribute($attr); } - } + } if (exists $options{methods}) { foreach my $method_name (keys %{$options{methods}}) { $meta->add_method($method_name, $options{methods}->{$method_name}); } - } + } return $meta; } ## Attribute readers # NOTE: -# all these attribute readers will be bootstrapped +# all these attribute readers will be bootstrapped # away in the Class::MOP bootstrap section sub get_attribute_map { $_[0]->{'%!attributes'} } @@ -268,27 +298,49 @@ sub instance_metaclass { $_[0]->{'$!instance_metaclass'} } # FIXME: # this is a prime canidate for conversion to XS -sub get_method_map { +sub get_method_map { my $self = shift; - my $map = $self->{'%!methods'}; + if (defined $self->{'$!_package_cache_flag'} && + $self->{'$!_package_cache_flag'} == Class::MOP::check_package_cache_flag($self->name)) { + return $self->{'%!methods'}; + } + + my $map = $self->{'%!methods'}; + my $class_name = $self->name; my $method_metaclass = $self->method_metaclass; - - foreach my $symbol ($self->list_all_package_symbols('CODE')) { - my $code = $self->get_package_symbol('&' . $symbol); - - next if exists $map->{$symbol} && - defined $map->{$symbol} && - $map->{$symbol}->body == $code; - - my $gv = svref_2object($code)->GV; - next if ($gv->STASH->NAME || '') ne $class_name && - ($gv->NAME || '') ne '__ANON__'; + + my %all_code = $self->get_all_package_symbols('CODE'); + + foreach my $symbol (keys %all_code) { + my $code = $all_code{$symbol}; + + next if exists $map->{$symbol} && + defined $map->{$symbol} && + $map->{$symbol}->body == $code; + + my ($pkg, $name) = Class::MOP::get_code_info($code); - $map->{$symbol} = $method_metaclass->wrap($code); + # NOTE: + # in 5.10 constant.pm the constants show up + # as being in the right package, but in pre-5.10 + # they show up as constant::__ANON__ so we + # make an exception here to be sure that things + # work as expected in both. + # - SL + unless ($pkg eq 'constant' && $name eq '__ANON__') { + next if ($pkg || '') ne $class_name || + (($name || '') ne '__ANON__' && ($pkg || '') ne $class_name); + } + + $map->{$symbol} = $method_metaclass->wrap( + $code, + package_name => $class_name, + name => $symbol, + ); } - + return $map; } @@ -297,7 +349,7 @@ sub get_method_map { sub new_object { my $class = shift; # NOTE: - # we need to protect the integrity of the + # we need to protect the integrity of the # Class::MOP::Class singletons here, so we # delegate this to &construct_class_instance # which will deal with the singletons @@ -313,14 +365,14 @@ sub construct_instance { foreach my $attr ($class->compute_all_applicable_attributes()) { $attr->initialize_instance_slot($meta_instance, $instance, \%params); } - # NOTE: + # NOTE: # this will only work for a HASH instance type if ($class->is_anon_class) { - (reftype($instance) eq 'HASH') + (Scalar::Util::reftype($instance) eq 'HASH') || confess "Currently only HASH based instances are supported with instance of anon-classes"; # NOTE: # At some point we should make this official - # as a reserved slot name, but right now I am + # as a reserved slot name, but right now I am # going to keep it here. # my $RESERVED_MOP_SLOT = '__MOP__'; $instance->{'__MOP__'} = $class; @@ -328,24 +380,39 @@ sub construct_instance { return $instance; } + sub get_meta_instance { - my $class = shift; - return $class->instance_metaclass->new( - $class, - $class->compute_all_applicable_attributes() + my $self = shift; + # NOTE: + # just about any fiddling with @ISA or + # any fiddling with attributes will + # also fiddle with the symbol table + # and therefore invalidate the package + # cache, in which case we should blow + # away the meta-instance cache. Of course + # this will invalidate it more often then + # is probably needed, but better safe + # then sorry. + # - SL + $self->{'$!_meta_instance'} = undef + if defined $self->{'$!_package_cache_flag'} && + $self->{'$!_package_cache_flag'} == Class::MOP::check_package_cache_flag($self->name); + $self->{'$!_meta_instance'} ||= $self->instance_metaclass->new( + $self, + $self->compute_all_applicable_attributes() ); } sub clone_object { my $class = shift; - my $instance = shift; + my $instance = shift; (blessed($instance) && $instance->isa($class->name)) || confess "You must pass an instance ($instance) of the metaclass (" . $class->name . ")"; # NOTE: - # we need to protect the integrity of the - # Class::MOP::Class singletons here, they + # we need to protect the integrity of the + # Class::MOP::Class singletons here, they # should not be cloned. - return $instance if $instance->isa('Class::MOP::Class'); + return $instance if $instance->isa('Class::MOP::Class'); $class->clone_instance($instance, @_); } @@ -354,48 +421,157 @@ sub clone_instance { (blessed($instance)) || confess "You can only clone instances, \$self is not a blessed instance"; my $meta_instance = $class->get_meta_instance(); - my $clone = $meta_instance->clone_instance($instance); + my $clone = $meta_instance->clone_instance($instance); foreach my $attr ($class->compute_all_applicable_attributes()) { - if (exists $params{$attr->init_arg}) { - $meta_instance->set_slot_value($clone, $attr->name, $params{$attr->init_arg}); + if ( defined( my $init_arg = $attr->init_arg ) ) { + if (exists $params{$init_arg}) { + $attr->set_value($clone, $params{$init_arg}); + } } - } - return $clone; + } + return $clone; +} + +sub rebless_instance { + my ($self, $instance, %params) = @_; + + my $old_metaclass; + if ($instance->can('meta')) { + ($instance->meta->isa('Class::MOP::Class')) + || confess 'Cannot rebless instance if ->meta is not an instance of Class::MOP::Class'; + $old_metaclass = $instance->meta; + } + else { + $old_metaclass = $self->initialize(blessed($instance)); + } + + my $meta_instance = $self->get_meta_instance(); + + $self->name->isa($old_metaclass->name) + || confess "You may rebless only into a subclass of (". $old_metaclass->name ."), of which (". $self->name .") isn't."; + + # rebless! + $meta_instance->rebless_instance_structure($instance, $self); + + foreach my $attr ( $self->compute_all_applicable_attributes ) { + if ( $attr->has_value($instance) ) { + if ( defined( my $init_arg = $attr->init_arg ) ) { + $params{$init_arg} = $attr->get_value($instance) + unless exists $params{$init_arg}; + } + else { + $attr->set_value($instance, $attr->get_value($instance)); + } + } + } + + foreach my $attr ($self->compute_all_applicable_attributes) { + $attr->initialize_instance_slot($meta_instance, $instance, \%params); + } + + $instance; } # Inheritance sub superclasses { - my $self = shift; + my $self = shift; + my $var_spec = { sigil => '@', type => 'ARRAY', name => 'ISA' }; if (@_) { my @supers = @_; - @{$self->get_package_symbol('@ISA')} = @supers; + @{$self->get_package_symbol($var_spec)} = @supers; # NOTE: - # we need to check the metaclass - # compatability here so that we can - # be sure that the superclass is - # not potentially creating an issues + # we need to check the metaclass + # compatibility here so that we can + # be sure that the superclass is + # not potentially creating an issues # we don't know about $self->check_metaclass_compatability(); } - @{$self->get_package_symbol('@ISA')}; + @{$self->get_package_symbol($var_spec)}; +} + +sub subclasses { + my $self = shift; + + my $super_class = $self->name; + my @derived_classes; + + my $find_derived_classes; + $find_derived_classes = sub { + my ($outer_class) = @_; + + my $symbol_table_hashref = do { no strict 'refs'; \%{"${outer_class}::"} }; + + SYMBOL: + for my $symbol ( keys %$symbol_table_hashref ) { + next SYMBOL if $symbol !~ /\A (\w+):: \z/x; + my $inner_class = $1; + + next SYMBOL if $inner_class eq 'SUPER'; # skip '*::SUPER' + + my $class = + $outer_class + ? "${outer_class}::$inner_class" + : $inner_class; + + if ( $class->isa($super_class) and $class ne $super_class ) { + push @derived_classes, $class; + } + + next SYMBOL if $class eq 'main'; # skip 'main::*' + + $find_derived_classes->($class); + } + }; + + my $root_class = q{}; + $find_derived_classes->($root_class); + + undef $find_derived_classes; + + @derived_classes = sort { $a->isa($b) ? 1 : $b->isa($a) ? -1 : 0 } @derived_classes; + + return @derived_classes; +} + + +sub linearized_isa { + return @{ mro::get_linear_isa( (shift)->name ) }; } sub class_precedence_list { my $self = shift; - # NOTE: - # We need to check for ciruclar inheirtance here. - # This will do nothing if all is well, and blow - # up otherwise. Yes, it's an ugly hack, better - # suggestions are welcome. - { ($self->name || return)->isa('This is a test for circular inheritance') } - # ... and now back to our regularly scheduled program - ( - $self->name, - map { - $self->initialize($_)->class_precedence_list() - } $self->superclasses() - ); + my $name = $self->name; + + unless (Class::MOP::IS_RUNNING_ON_5_10()) { + # NOTE: + # We need to check for circular inheritance here + # if we are are not on 5.10, cause 5.8 detects it + # late. This will do nothing if all is well, and + # blow up otherwise. Yes, it's an ugly hack, better + # suggestions are welcome. + # - SL + ($name || return)->isa('This is a test for circular inheritance') + } + + # if our mro is c3, we can + # just grab the linear_isa + if (mro::get_mro($name) eq 'c3') { + return @{ mro::get_linear_isa($name) } + } + else { + # NOTE: + # we can't grab the linear_isa for dfs + # since it has all the duplicates + # already removed. + return ( + $name, + map { + $self->initialize($_)->class_precedence_list() + } $self->superclasses() + ); + } } ## Methods @@ -404,21 +580,40 @@ sub add_method { my ($self, $method_name, $method) = @_; (defined $method_name && $method_name) || confess "You must define a method name"; - + my $body; if (blessed($method)) { - $body = $method->body; + $body = $method->body; + if ($method->package_name ne $self->name && + $method->name ne $method_name) { + warn "Hello there, got somethig for you." + . " Method says " . $method->package_name . " " . $method->name + . " Class says " . $self->name . " " . $method_name; + $method = $method->clone( + package_name => $self->name, + name => $method_name + ) if $method->can('clone'); + } } - else { + else { $body = $method; - ('CODE' eq (reftype($body) || '')) - || confess "Your code block must be a CODE reference"; - $method = $self->method_metaclass->wrap($body); + ('CODE' eq ref($body)) + || confess "Your code block must be a CODE reference"; + $method = $self->method_metaclass->wrap( + $body => ( + package_name => $self->name, + name => $method_name + ) + ); } $self->get_method_map->{$method_name} = $method; - my $full_method_name = ($self->name . '::' . $method_name); - $self->add_package_symbol("&${method_name}" => subname $full_method_name => $body); + my $full_method_name = ($self->name . '::' . $method_name); + $self->add_package_symbol( + { sigil => '&', type => 'CODE', name => $method_name }, + Class::MOP::subname($full_method_name => $body) + ); + $self->update_package_cache_flag; } { @@ -433,54 +628,60 @@ sub add_method { # die if it does not exist (defined $method) || confess "The method '$method_name' is not found in the inheritance hierarchy for class " . $self->name; - # and now make sure to wrap it + # and now make sure to wrap it # even if it is already wrapped # because we need a new sub ref $method = Class::MOP::Method::Wrapped->wrap($method); } else { - # now make sure we wrap it properly + # now make sure we wrap it properly $method = Class::MOP::Method::Wrapped->wrap($method) - unless $method->isa('Class::MOP::Method::Wrapped'); - } - $self->add_method($method_name => $method); + unless $method->isa('Class::MOP::Method::Wrapped'); + } + $self->add_method($method_name => $method); return $method; }; sub add_before_method_modifier { my ($self, $method_name, $method_modifier) = @_; (defined $method_name && $method_name) - || confess "You must pass in a method name"; + || confess "You must pass in a method name"; my $method = $fetch_and_prepare_method->($self, $method_name); - $method->add_before_modifier(subname ':before' => $method_modifier); + $method->add_before_modifier( + Class::MOP::subname(':before' => $method_modifier) + ); } sub add_after_method_modifier { my ($self, $method_name, $method_modifier) = @_; (defined $method_name && $method_name) - || confess "You must pass in a method name"; + || confess "You must pass in a method name"; my $method = $fetch_and_prepare_method->($self, $method_name); - $method->add_after_modifier(subname ':after' => $method_modifier); + $method->add_after_modifier( + Class::MOP::subname(':after' => $method_modifier) + ); } - + sub add_around_method_modifier { my ($self, $method_name, $method_modifier) = @_; (defined $method_name && $method_name) || confess "You must pass in a method name"; my $method = $fetch_and_prepare_method->($self, $method_name); - $method->add_around_modifier(subname ':around' => $method_modifier); - } + $method->add_around_modifier( + Class::MOP::subname(':around' => $method_modifier) + ); + } - # NOTE: + # NOTE: # the methods above used to be named like this: # ${pkg}::${method}:(before|after|around) # but this proved problematic when using one modifier # to wrap multiple methods (something which is likely # to happen pretty regularly IMO). So instead of naming - # it like this, I have chosen to just name them purely + # it like this, I have chosen to just name them purely # with their modifier names, like so: # :(before|after|around) - # The fact is that in a stack trace, it will be fairly + # The fact is that in a stack trace, it will be fairly # evident from the context what method they are attached # to, and so don't need the fully qualified name. } @@ -491,18 +692,21 @@ sub alias_method { || confess "You must define a method name"; my $body = (blessed($method) ? $method->body : $method); - ('CODE' eq (reftype($body) || '')) - || confess "Your code block must be a CODE reference"; - - $self->add_package_symbol("&${method_name}" => $body); + ('CODE' eq ref($body)) + || confess "Your code block must be a CODE reference"; + + $self->add_package_symbol( + { sigil => '&', type => 'CODE', name => $method_name } => $body + ); + $self->update_package_cache_flag; } sub has_method { my ($self, $method_name) = @_; (defined $method_name && $method_name) - || confess "You must define a method name"; - - return 0 unless exists $self->get_method_map->{$method_name}; + || confess "You must define a method name"; + + return 0 unless exists $self->get_method_map->{$method_name}; return 1; } @@ -510,13 +714,13 @@ sub get_method { my ($self, $method_name) = @_; (defined $method_name && $method_name) || confess "You must define a method name"; - + # NOTE: # I don't really need this here, because - # if the method_map is missing a key it + # if the method_map is missing a key it # will just return undef for me now # return unless $self->has_method($method_name); - + return $self->get_method_map->{$method_name}; } @@ -524,14 +728,15 @@ sub remove_method { my ($self, $method_name) = @_; (defined $method_name && $method_name) || confess "You must define a method name"; + + my $removed_method = delete $self->get_method_map->{$method_name}; - my $removed_method = $self->get_method($method_name); + $self->remove_package_symbol( + { sigil => '&', type => 'CODE', name => $method_name } + ); - do { - $self->remove_package_symbol("&${method_name}"); - delete $self->get_method_map->{$method_name}; - } if defined $removed_method; - + $self->update_package_cache_flag; + return $removed_method; } @@ -543,19 +748,11 @@ sub get_method_list { sub find_method_by_name { my ($self, $method_name) = @_; (defined $method_name && $method_name) - || confess "You must define a method name to find"; - # keep a record of what we have seen - # here, this will handle all the - # inheritence issues because we are - # using the &class_precedence_list - my %seen_class; - my @cpl = $self->class_precedence_list(); - foreach my $class (@cpl) { - next if $seen_class{$class}; - $seen_class{$class}++; + || confess "You must define a method name to find"; + foreach my $class ($self->linearized_isa) { # fetch the meta-class ... my $meta = $self->initialize($class); - return $meta->get_method($method_name) + return $meta->get_method($method_name) if $meta->has_method($method_name); } return; @@ -563,22 +760,15 @@ sub find_method_by_name { sub compute_all_applicable_methods { my $self = shift; - my @methods; - # keep a record of what we have seen - # here, this will handle all the - # inheritence issues because we are - # using the &class_precedence_list - my (%seen_class, %seen_method); - foreach my $class ($self->class_precedence_list()) { - next if $seen_class{$class}; - $seen_class{$class}++; + my (@methods, %seen_method); + foreach my $class ($self->linearized_isa) { # fetch the meta-class ... my $meta = $self->initialize($class); - foreach my $method_name ($meta->get_method_list()) { + foreach my $method_name ($meta->get_method_list()) { next if exists $seen_method{$method_name}; $seen_method{$method_name}++; push @methods => { - name => $method_name, + name => $method_name, class => $class, code => $meta->get_method($method_name) }; @@ -590,20 +780,13 @@ sub compute_all_applicable_methods { sub find_all_methods_by_name { my ($self, $method_name) = @_; (defined $method_name && $method_name) - || confess "You must define a method name to find"; + || confess "You must define a method name to find"; my @methods; - # keep a record of what we have seen - # here, this will handle all the - # inheritence issues because we are - # using the &class_precedence_list - my %seen_class; - foreach my $class ($self->class_precedence_list()) { - next if $seen_class{$class}; - $seen_class{$class}++; + foreach my $class ($self->linearized_isa) { # fetch the meta-class ... my $meta = $self->initialize($class); push @methods => { - name => $method_name, + name => $method_name, class => $class, code => $meta->get_method($method_name) } if $meta->has_method($method_name); @@ -614,20 +797,13 @@ sub find_all_methods_by_name { sub find_next_method_by_name { my ($self, $method_name) = @_; (defined $method_name && $method_name) - || confess "You must define a method name to find"; - # keep a record of what we have seen - # here, this will handle all the - # inheritence issues because we are - # using the &class_precedence_list - my %seen_class; - my @cpl = $self->class_precedence_list(); + || confess "You must define a method name to find"; + my @cpl = $self->linearized_isa; shift @cpl; # discard ourselves foreach my $class (@cpl) { - next if $seen_class{$class}; - $seen_class{$class}++; # fetch the meta-class ... my $meta = $self->initialize($class); - return $meta->get_method($method_name) + return $meta->get_method($method_name) if $meta->has_method($method_name); } return; @@ -642,20 +818,20 @@ sub add_attribute { my $attribute = blessed($_[0]) ? $_[0] : $self->attribute_metaclass->new(@_); # make sure it is derived from the correct type though ($attribute->isa('Class::MOP::Attribute')) - || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)"; + || confess "Your attribute must be an instance of Class::MOP::Attribute (or a subclass)"; # first we attach our new attribute - # because it might need certain information + # because it might need certain information # about the class which it is attached to $attribute->attach_to_class($self); - - # then we remove attributes of a conflicting - # name here so that we can properly detach - # the old attr object, and remove any + + # then we remove attributes of a conflicting + # name here so that we can properly detach + # the old attr object, and remove any # accessors it would have generated $self->remove_attribute($attribute->name) if $self->has_attribute($attribute->name); - + # then onto installing the new accessors $attribute->install_accessors(); $self->get_attribute_map->{$attribute->name} = $attribute; @@ -665,69 +841,55 @@ sub has_attribute { my ($self, $attribute_name) = @_; (defined $attribute_name && $attribute_name) || confess "You must define an attribute name"; - exists $self->get_attribute_map->{$attribute_name} ? 1 : 0; -} + exists $self->get_attribute_map->{$attribute_name} ? 1 : 0; +} sub get_attribute { my ($self, $attribute_name) = @_; (defined $attribute_name && $attribute_name) || confess "You must define an attribute name"; - return $self->get_attribute_map->{$attribute_name} + return $self->get_attribute_map->{$attribute_name} # NOTE: # this will return undef anyway, so no need ... - # if $self->has_attribute($attribute_name); - #return; -} + # if $self->has_attribute($attribute_name); + #return; +} sub remove_attribute { my ($self, $attribute_name) = @_; (defined $attribute_name && $attribute_name) || confess "You must define an attribute name"; - my $removed_attribute = $self->get_attribute_map->{$attribute_name}; + my $removed_attribute = $self->get_attribute_map->{$attribute_name}; return unless defined $removed_attribute; - delete $self->get_attribute_map->{$attribute_name}; - $removed_attribute->remove_accessors(); + delete $self->get_attribute_map->{$attribute_name}; + $removed_attribute->remove_accessors(); $removed_attribute->detach_from_class(); return $removed_attribute; -} +} sub get_attribute_list { my $self = shift; keys %{$self->get_attribute_map}; -} +} sub compute_all_applicable_attributes { my $self = shift; - my @attrs; - # keep a record of what we have seen - # here, this will handle all the - # inheritence issues because we are - # using the &class_precedence_list - my (%seen_class, %seen_attr); - foreach my $class ($self->class_precedence_list()) { - next if $seen_class{$class}; - $seen_class{$class}++; + my (@attrs, %seen_attr); + foreach my $class ($self->linearized_isa) { # fetch the meta-class ... my $meta = $self->initialize($class); - foreach my $attr_name ($meta->get_attribute_list()) { + foreach my $attr_name ($meta->get_attribute_list()) { next if exists $seen_attr{$attr_name}; $seen_attr{$attr_name}++; push @attrs => $meta->get_attribute($attr_name); } } - return @attrs; + return @attrs; } sub find_attribute_by_name { my ($self, $attr_name) = @_; - # keep a record of what we have seen - # here, this will handle all the - # inheritence issues because we are - # using the &class_precedence_list - my %seen_class; - foreach my $class ($self->class_precedence_list()) { - next if $seen_class{$class}; - $seen_class{$class}++; + foreach my $class ($self->linearized_isa) { # fetch the meta-class ... my $meta = $self->initialize($class); return $meta->get_attribute($attr_name) @@ -741,38 +903,91 @@ sub find_attribute_by_name { sub is_mutable { 1 } sub is_immutable { 0 } +# NOTE: +# Why I changed this (groditi) +# - One Metaclass may have many Classes through many Metaclass instances +# - One Metaclass should only have one Immutable Transformer instance +# - Each Class may have different Immutabilizing options +# - Therefore each Metaclass instance may have different Immutabilizing options +# - We need to store one Immutable Transformer instance per Metaclass +# - We need to store one set of Immutable Transformer options per Class +# - Upon make_mutable we may delete the Immutabilizing options +# - We could clean the immutable Transformer instance when there is no more +# immutable Classes of that type, but we can also keep it in case +# another class with this same Metaclass becomes immutable. It is a case +# of trading of storing an instance to avoid unnecessary instantiations of +# Immutable Transformers. You may view this as a memory leak, however +# Because we have few Metaclasses, in practice it seems acceptable +# - To allow Immutable Transformers instances to be cleaned up we could weaken +# the reference stored in $IMMUTABLE_TRANSFORMERS{$class} and ||= should DWIM + { - # NOTE: - # the immutable version of a - # particular metaclass is - # really class-level data so - # we don't want to regenerate - # it any more than we need to - my $IMMUTABLE_METACLASS; + my %IMMUTABLE_TRANSFORMERS; + my %IMMUTABLE_OPTIONS; sub make_immutable { - my ($self) = @_; - - $IMMUTABLE_METACLASS ||= Class::MOP::Immutable->new($self, { - read_only => [qw/superclasses/], - cannot_call => [qw/ - add_method - alias_method - remove_method - add_attribute - remove_attribute - add_package_symbol - remove_package_symbol - /], - memoize => { - class_precedence_list => 'ARRAY', - compute_all_applicable_attributes => 'ARRAY', - get_meta_instance => 'SCALAR', - get_method_map => 'SCALAR', - } - }); + my $self = shift; + my %options = @_; + my $class = blessed $self || $self; + + $IMMUTABLE_TRANSFORMERS{$class} ||= $self->create_immutable_transformer; + my $transformer = $IMMUTABLE_TRANSFORMERS{$class}; + + $transformer->make_metaclass_immutable($self, \%options); + $IMMUTABLE_OPTIONS{$self->name} = + { %options, IMMUTABLE_TRANSFORMER => $transformer }; + + if( exists $options{debug} && $options{debug} ){ + print STDERR "# of Metaclass options: ", keys %IMMUTABLE_OPTIONS; + print STDERR "# of Immutable transformers: ", keys %IMMUTABLE_TRANSFORMERS; + } - $IMMUTABLE_METACLASS->make_metaclass_immutable(@_) + 1; } + + sub make_mutable{ + my $self = shift; + return if $self->is_mutable; + my $options = delete $IMMUTABLE_OPTIONS{$self->name}; + confess "unable to find immutabilizing options" unless ref $options; + my $transformer = delete $options->{IMMUTABLE_TRANSFORMER}; + $transformer->make_metaclass_mutable($self, $options); + 1; + } +} + +sub create_immutable_transformer { + my $self = shift; + my $class = Class::MOP::Immutable->new($self, { + read_only => [qw/superclasses/], + cannot_call => [qw/ + add_method + alias_method + remove_method + add_attribute + remove_attribute + remove_package_symbol + /], + memoize => { + class_precedence_list => 'ARRAY', + linearized_isa => 'ARRAY', + compute_all_applicable_attributes => 'ARRAY', + get_meta_instance => 'SCALAR', + get_method_map => 'SCALAR', + }, + # NOTE: + # this is ugly, but so are typeglobs, + # so whattayahgonnadoboutit + # - SL + wrapped => { + add_package_symbol => sub { + my $original = shift; + confess "Cannot add package symbols to an immutable metaclass" + unless (caller(2))[3] eq 'Class::MOP::Package::get_package_symbol'; + goto $original->body; + }, + }, + }); + return $class; } 1; @@ -781,48 +996,48 @@ __END__ =pod -=head1 NAME +=head1 NAME Class::MOP::Class - Class Meta Object =head1 SYNOPSIS - # assuming that class Foo + # assuming that class Foo # has been defined, you can - + # use this for introspection ... - + # add a method to Foo ... Foo->meta->add_method('bar' => sub { ... }) - - # get a list of all the classes searched - # the method dispatcher in the correct order + + # get a list of all the classes searched + # the method dispatcher in the correct order Foo->meta->class_precedence_list() - + # remove a method from Foo Foo->meta->remove_method('bar'); - + # or use this to actually create classes ... - + Class::MOP::Class->create('Bar' => ( version => '0.01', superclasses => [ 'Foo' ], attributes => [ Class::MOP:::Attribute->new('$bar'), - Class::MOP:::Attribute->new('$baz'), + Class::MOP:::Attribute->new('$baz'), ], methods => { calculate_bar => sub { ... }, - construct_baz => sub { ... } + construct_baz => sub { ... } } )); =head1 DESCRIPTION -This is the largest and currently most complex part of the Perl 5 -meta-object protocol. It controls the introspection and -manipulation of Perl 5 classes (and it can create them too). The -best way to understand what this module can do, is to read the +This is the largest and currently most complex part of the Perl 5 +meta-object protocol. It controls the introspection and +manipulation of Perl 5 classes (and it can create them too). The +best way to understand what this module can do, is to read the documentation for each of it's methods. =head1 METHODS @@ -833,132 +1048,147 @@ documentation for each of it's methods. =item B -This will return a B instance which is related -to this class. Thereby allowing B to actually +This will return a B instance which is related +to this class. Thereby allowing B to actually introspect itself. -As with B, B will actually -bootstrap this module by installing a number of attribute meta-objects -into it's metaclass. This will allow this class to reap all the benifits -of the MOP when subclassing it. +As with B, B will actually +bootstrap this module by installing a number of attribute meta-objects +into it's metaclass. This will allow this class to reap all the benifits +of the MOP when subclassing it. =back =head2 Class construction -These methods will handle creating B objects, -which can be used to both create new classes, and analyze -pre-existing classes. +These methods will handle creating B objects, +which can be used to both create new classes, and analyze +pre-existing classes. -This module will internally store references to all the instances -you create with these methods, so that they do not need to be +This module will internally store references to all the instances +you create with these methods, so that they do not need to be created any more than nessecary. Basically, they are singletons. =over 4 -=item B ?$version, - authority =E ?$authority, - superclasses =E ?@superclasses, - methods =E ?%methods, +=item B ?$version, + authority =E ?$authority, + superclasses =E ?@superclasses, + methods =E ?%methods, attributes =E ?%attributes)> -This returns a B object, bringing the specified -C<$package_name> into existence and adding any of the C<$version>, -C<$authority>, C<@superclasses>, C<%methods> and C<%attributes> to +This returns a B object, bringing the specified +C<$package_name> into existence and adding any of the C<$version>, +C<$authority>, C<@superclasses>, C<%methods> and C<%attributes> to it. -=item B ?@superclasses, - methods =E ?%methods, +=item B ?@superclasses, + methods =E ?%methods, attributes =E ?%attributes)> -This will create an anonymous class, it works much like C but -it does not need a C<$package_name>. Instead it will create a suitably +This will create an anonymous class, it works much like C but +it does not need a C<$package_name>. Instead it will create a suitably unique package name for you to stash things into. -On very important distinction is that anon classes are destroyed once -the metaclass they are attached to goes out of scope. In the DESTROY -method, the created package will be removed from the symbol table. +On very important distinction is that anon classes are destroyed once +the metaclass they are attached to goes out of scope. In the DESTROY +method, the created package will be removed from the symbol table. It is also worth noting that any instances created with an anon-class -will keep a special reference to the anon-meta which will prevent the -anon-class from going out of scope until all instances of it have also -been destroyed. This however only works for HASH based instance types, -as we use a special reserved slot (C<__MOP__>) to store this. +will keep a special reference to the anon-meta which will prevent the +anon-class from going out of scope until all instances of it have also +been destroyed. This however only works for HASH based instance types, +as we use a special reserved slot (C<__MOP__>) to store this. =item B -This initializes and returns returns a B object +This initializes and returns returns a B object for a given a C<$package_name>. =item B This removes the old metaclass, and creates a new one in it's place. -Do B use this unless you really know what you are doing, it could -very easily make a very large mess of your program. +Do B use this unless you really know what you are doing, it could +very easily make a very large mess of your program. =item B -This will construct an instance of B, it is -here so that we can actually "tie the knot" for B -to use C once all the bootstrapping is done. This +This will construct an instance of B, it is +here so that we can actually "tie the knot" for B +to use C once all the bootstrapping is done. This method is used internally by C and should never be called from outside of that method really. =item B -This method is called as the very last thing in the -C method. This will check that the -metaclass you are creating is compatible with the metaclasses of all -your ancestors. For more inforamtion about metaclass compatibility +This method is called as the very last thing in the +C method. This will check that the +metaclass you are creating is compatible with the metaclasses of all +your ancestors. For more inforamtion about metaclass compatibility see the C section in L. +=item B + +This will reset the package cache flag for this particular metaclass +it is basically the value of the C +function. This is very rarely needed from outside of C +but in some cases you might want to use it, so it is here. + +=item B + +Clears the package cache flag to announce to the internals that we need +to rebuild the method map. + =back =head2 Object instance construction and cloning -These methods are B, it is up to you whether you want +These methods are B, it is up to you whether you want to use them or not. =over 4 =item B +Returns the class name of the instance metaclass, see L +for more information on the instance metaclasses. + =item B +Returns an instance of L to be used in the construction +of a new instance of the class. + =item B -This is a convience method for creating a new object of the class, and -blessing it into the appropriate package as well. Ideally your class +This is a convience method for creating a new object of the class, and +blessing it into the appropriate package as well. Ideally your class would call a C this method like so: - sub MyClass::new { + sub MyClass::new { my ($class, %param) = @_; $class->meta->new_object(%params); } -Of course the ideal place for this would actually be in C -but that is considered bad style, so we do not do that. - =item B -This method is used to construct an instace structure suitable for -C-ing into your package of choice. It works in conjunction +This method is used to construct an instance structure suitable for +C-ing into your package of choice. It works in conjunction with the Attribute protocol to collect all applicable attributes. -This will construct and instance using a HASH ref as storage -(currently only HASH references are supported). This will collect all -the applicable attributes and layout out the fields in the HASH ref, -it will then initialize them using either use the corresponding key -in C<%params> or any default value or initializer found in the +This will construct and instance using a HASH ref as storage +(currently only HASH references are supported). This will collect all +the applicable attributes and layout out the fields in the HASH ref, +it will then initialize them using either use the corresponding key +in C<%params> or any default value or initializer found in the attribute meta-object. =item B -This is a convience method for cloning an object instance, then -blessing it into the appropriate package. This method will call -C, which performs a shallow copy of the object, -see that methods documentation for more details. Ideally your +This is a convience method for cloning an object instance, then +blessing it into the appropriate package. This method will call +C, which performs a shallow copy of the object, +see that methods documentation for more details. Ideally your class would call a C this method like so: sub MyClass::clone { @@ -966,30 +1196,34 @@ class would call a C this method like so: $self->meta->clone_object($self, %params); } -Of course the ideal place for this would actually be in C -but that is considered bad style, so we do not do that. - =item B -This method is a compliment of C (which means if -you override C, you need to override this one too), +This method is a compliment of C (which means if +you override C, you need to override this one too), and clones the instance shallowly. -The cloned structure returned is (like with C) an -unCed HASH reference, it is your responsibility to then bless +The cloned structure returned is (like with C) an +unCed HASH reference, it is your responsibility to then bless this cloned structure into the right class (which C will do for you). -As of 0.11, this method will clone the C<$instance> structure shallowly, -as opposed to the deep cloning implemented in prior versions. After much -thought, research and discussion, I have decided that anything but basic -shallow cloning is outside the scope of the meta-object protocol. I -think Yuval "nothingmuch" Kogman put it best when he said that cloning +As of 0.11, this method will clone the C<$instance> structure shallowly, +as opposed to the deep cloning implemented in prior versions. After much +thought, research and discussion, I have decided that anything but basic +shallow cloning is outside the scope of the meta-object protocol. I +think Yuval "nothingmuch" Kogman put it best when he said that cloning is too I to be part of the MOP. +=item B + +This will change the class of C<$instance> to the class of the invoking +C. You may only rebless the instance to a subclass of +itself. You may pass in optional C<%params> which are like constructor +params and will override anything already defined in the instance. + =back -=head2 Informational +=head2 Informational These are a few predicate methods for asking information about the class. @@ -1015,22 +1249,24 @@ This returns true if the class has been made immutable. =item B -This is a read-write attribute which represents the superclass +This is a read-write attribute which represents the superclass relationships of the class the B instance is associated with. Basically, it can get and set the C<@ISA> for you. -B -Perl will occasionally perform some C<@ISA> and method caching, if -you decide to change your superclass relationship at runtime (which -is quite insane and very much not recommened), then you should be -aware of this and the fact that this module does not make any -attempt to address this issue. - =item B -This computes the a list of all the class's ancestors in the same order -in which method dispatch will be done. This is similair to -what B does, but we don't remove duplicate names. +This computes the a list of all the class's ancestors in the same order +in which method dispatch will be done. This is similair to what +B does, but we don't remove duplicate names. + +=item B + +This returns a list based on C but with all +duplicates removed. + +=item B + +This returns a list of subclasses for this class. =back @@ -1040,62 +1276,67 @@ what B does, but we don't remove duplicate names. =item B +Returns a HASH ref of name to CODE reference mapping for this class. + =item B +Returns the class name of the method metaclass, see L +for more information on the method metaclasses. + =item B -This will take a C<$method_name> and CODE reference to that -C<$method> and install it into the class's package. +This will take a C<$method_name> and CODE reference to that +C<$method> and install it into the class's package. -B: -This does absolutely nothing special to C<$method> -other than use B to make sure it is tagged with the -correct name, and therefore show up correctly in stack traces and +B: +This does absolutely nothing special to C<$method> +other than use B to make sure it is tagged with the +correct name, and therefore show up correctly in stack traces and such. =item B -This will take a C<$method_name> and CODE reference to that -C<$method> and alias the method into the class's package. +This will take a C<$method_name> and CODE reference to that +C<$method> and alias the method into the class's package. -B: -Unlike C, this will B try to name the -C<$method> using B, it only aliases the method in -the class's package. +B: +Unlike C, this will B try to name the +C<$method> using B, it only aliases the method in +the class's package. =item B -This just provides a simple way to check if the class implements -a specific C<$method_name>. It will I however, attempt to check +This just provides a simple way to check if the class implements +a specific C<$method_name>. It will I however, attempt to check if the class inherits the method (use C for that). -This will correctly handle functions defined outside of the package +This will correctly handle functions defined outside of the package that use a fully qualified name (C). -This will correctly handle functions renamed with B and -installed using the symbol tables. However, if you are naming the -subroutine outside of the package scope, you must use the fully -qualified name, including the package name, for C to -correctly identify it. +This will correctly handle functions renamed with B and +installed using the symbol tables. However, if you are naming the +subroutine outside of the package scope, you must use the fully +qualified name, including the package name, for C to +correctly identify it. -This will attempt to correctly ignore functions imported from other -packages using B. It breaks down if the function imported -is an C<__ANON__> sub (such as with C), which very well -may be a valid method being applied to the class. +This will attempt to correctly ignore functions imported from other +packages using B. It breaks down if the function imported +is an C<__ANON__> sub (such as with C), which very well +may be a valid method being applied to the class. -In short, this method cannot always be trusted to determine if the -C<$method_name> is actually a method. However, it will DWIM about +In short, this method cannot always be trusted to determine if the +C<$method_name> is actually a method. However, it will DWIM about 90% of the time, so it's a small trade off I think. =item B -This will return a Class::MOP::Method instance related to the specified +This will return a Class::MOP::Method instance related to the specified C<$method_name>, or return undef if that method does not exist. -The Class::MOP::Method is codifiable, so you can use it like a normal +The Class::MOP::Method is codifiable, so you can use it like a normal CODE reference, see L for more information. -=item B +=item B This will return a CODE reference of the specified C<$method_name>, or return undef if that method does not exist. @@ -1104,76 +1345,76 @@ Unlike C this will also look in the superclasses. =item B -This will attempt to remove a given C<$method_name> from the class. -It will return the CODE reference that it has removed, and will +This will attempt to remove a given C<$method_name> from the class. +It will return the CODE reference that it has removed, and will attempt to use B to clear the methods associated name. =item B -This will return a list of method names for all I defined -methods. It does B provide a list of all applicable methods, -including any inherited ones. If you want a list of all applicable +This will return a list of method names for all I defined +methods. It does B provide a list of all applicable methods, +including any inherited ones. If you want a list of all applicable methods, use the C method. =item B -This will return a list of all the methods names this class will -respond to, taking into account inheritance. The list will be a list of -HASH references, each one containing the following information; method -name, the name of the class in which the method lives and a CODE +This will return a list of all the methods names this class will +respond to, taking into account inheritance. The list will be a list of +HASH references, each one containing the following information; method +name, the name of the class in which the method lives and a CODE reference for the actual method. =item B -This will traverse the inheritence hierarchy and locate all methods -with a given C<$method_name>. Similar to -C it returns a list of HASH references -with the following information; method name (which will always be the -same as C<$method_name>), the name of the class in which the method +This will traverse the inheritence hierarchy and locate all methods +with a given C<$method_name>. Similar to +C it returns a list of HASH references +with the following information; method name (which will always be the +same as C<$method_name>), the name of the class in which the method lives and a CODE reference for the actual method. -The list of methods produced is a distinct list, meaning there are no -duplicates in it. This is especially useful for things like object -initialization and destruction where you only want the method called +The list of methods produced is a distinct list, meaning there are no +duplicates in it. This is especially useful for things like object +initialization and destruction where you only want the method called once, and in the correct order. =item B -This will return the first method to match a given C<$method_name> in -the superclasses, this is basically equivalent to calling +This will return the first method to match a given C<$method_name> in +the superclasses, this is basically equivalent to calling C, but it can be dispatched at runtime. =back =head2 Method Modifiers -Method modifiers are a concept borrowed from CLOS, in which a method -can be wrapped with I, I and I method modifiers -that will be called everytime the method is called. +Method modifiers are a concept borrowed from CLOS, in which a method +can be wrapped with I, I and I method modifiers +that will be called everytime the method is called. =head3 How method modifiers work? -Method modifiers work by wrapping the original method and then replacing -it in the classes symbol table. The wrappers will handle calling all the -modifiers in the appropariate orders and preserving the calling context -for the original method. - -Each method modifier serves a particular purpose, which may not be -obvious to users of other method wrapping modules. To start with, the -return values of I and I modifiers are ignored. This is -because thier purpose is B to filter the input and output of the -primary method (this is done with an I modifier). This may seem -like an odd restriction to some, but doing this allows for simple code -to be added at the begining or end of a method call without jeapordizing -the normal functioning of the primary method or placing any extra -responsibility on the code of the modifier. Of course if you have more -complex needs, then use the I modifier, which uses a variation -of continutation passing style to allow for a high degree of flexibility. - -Before and around modifiers are called in last-defined-first-called order, -while after modifiers are called in first-defined-first-called order. So +Method modifiers work by wrapping the original method and then replacing +it in the classes symbol table. The wrappers will handle calling all the +modifiers in the appropariate orders and preserving the calling context +for the original method. + +Each method modifier serves a particular purpose, which may not be +obvious to users of other method wrapping modules. To start with, the +return values of I and I modifiers are ignored. This is +because thier purpose is B to filter the input and output of the +primary method (this is done with an I modifier). This may seem +like an odd restriction to some, but doing this allows for simple code +to be added at the begining or end of a method call without jeapordizing +the normal functioning of the primary method or placing any extra +responsibility on the code of the modifier. Of course if you have more +complex needs, then use the I modifier, which uses a variation +of continutation passing style to allow for a high degree of flexibility. + +Before and around modifiers are called in last-defined-first-called order, +while after modifiers are called in first-defined-first-called order. So the call tree might looks something like this: - + before 2 before 1 around 2 @@ -1182,19 +1423,19 @@ the call tree might looks something like this: after 1 after 2 -To see examples of using method modifiers, see the following examples -included in the distribution; F, F, -F and F. There is also a +To see examples of using method modifiers, see the following examples +included in the distribution; F, F, +F and F. There is also a classic CLOS usage example in the test F<017_add_method_modifier.t>. =head3 What is the performance impact? -Of course there is a performance cost associated with method modifiers, -but we have made every effort to make that cost be directly proportional +Of course there is a performance cost associated with method modifiers, +but we have made every effort to make that cost be directly proportional to the amount of modifier features you utilize. -The wrapping method does it's best to B do as much work as it -absolutely needs to. In order to do this we have moved some of the +The wrapping method does it's best to B do as much work as it +absolutely needs to. In order to do this we have moved some of the performance costs to set-up time, where they are easier to amortize. All this said, my benchmarks have indicated the following: @@ -1205,122 +1446,127 @@ All this said, my benchmarks have indicated the following: simple wrapper with simple around modifier 500-550% slower simple wrapper with all 3 modifiers 1100% slower -These numbers may seem daunting, but you must remember, every feature -comes with some cost. To put things in perspective, just doing a simple +These numbers may seem daunting, but you must remember, every feature +comes with some cost. To put things in perspective, just doing a simple C which does nothing but extract the name of the method called -and return it costs about 400% over a normal method call. +and return it costs about 400% over a normal method call. =over 4 =item B -This will wrap the method at C<$method_name> and the supplied C<$code> -will be passed the C<@_> arguments, and called before the original -method is called. As specified above, the return value of the I -method modifiers is ignored, and it's ability to modify C<@_> is -fairly limited. If you need to do either of these things, use an +This will wrap the method at C<$method_name> and the supplied C<$code> +will be passed the C<@_> arguments, and called before the original +method is called. As specified above, the return value of the I +method modifiers is ignored, and it's ability to modify C<@_> is +fairly limited. If you need to do either of these things, use an C method modifier. =item B -This will wrap the method at C<$method_name> so that the original -method will be called, it's return values stashed, and then the +This will wrap the method at C<$method_name> so that the original +method will be called, it's return values stashed, and then the supplied C<$code> will be passed the C<@_> arguments, and called. -As specified above, the return value of the I method -modifiers is ignored, and it cannot modify the return values of -the original method. If you need to do either of these things, use an +As specified above, the return value of the I method +modifiers is ignored, and it cannot modify the return values of +the original method. If you need to do either of these things, use an C method modifier. =item B -This will wrap the method at C<$method_name> so that C<$code> -will be called and passed the original method as an extra argument -at the begining of the C<@_> argument list. This is a variation of -continuation passing style, where the function prepended to C<@_> -can be considered a continuation. It is up to C<$code> if it calls -the original method or not, there is no restriction on what the +This will wrap the method at C<$method_name> so that C<$code> +will be called and passed the original method as an extra argument +at the begining of the C<@_> argument list. This is a variation of +continuation passing style, where the function prepended to C<@_> +can be considered a continuation. It is up to C<$code> if it calls +the original method or not, there is no restriction on what the C<$code> can or cannot do. =back =head2 Attributes -It should be noted that since there is no one consistent way to define -the attributes of a class in Perl 5. These methods can only work with -the information given, and can not easily discover information on +It should be noted that since there is no one consistent way to define +the attributes of a class in Perl 5. These methods can only work with +the information given, and can not easily discover information on their own. See L for more details. =over 4 =item B +Returns the class name of the attribute metaclass, see L +for more information on the attribute metaclasses. + =item B -=item B +This returns a HASH ref of name to attribute meta-object mapping. + +=item B This stores the C<$attribute_meta_object> (or creates one from the -C<$attribute_name> and C<%attribute_spec>) in the B -instance associated with the given class. Unlike methods, attributes -within the MOP are stored as meta-information only. They will be used +C<$attribute_name> and C<%attribute_spec>) in the B +instance associated with the given class. Unlike methods, attributes +within the MOP are stored as meta-information only. They will be used later to construct instances from (see C above). -More details about the attribute meta-objects can be found in the +More details about the attribute meta-objects can be found in the L or the L section. -It should be noted that any accessor, reader/writer or predicate -methods which the C<$attribute_meta_object> has will be installed +It should be noted that any accessor, reader/writer or predicate +methods which the C<$attribute_meta_object> has will be installed into the class at this time. B -If an attribute already exists for C<$attribute_name>, the old one -will be removed (as well as removing all it's accessors), and then +If an attribute already exists for C<$attribute_name>, the old one +will be removed (as well as removing all it's accessors), and then the new one added. =item B -Checks to see if this class has an attribute by the name of +Checks to see if this class has an attribute by the name of C<$attribute_name> and returns a boolean. =item B -Returns the attribute meta-object associated with C<$attribute_name>, -if none is found, it will return undef. +Returns the attribute meta-object associated with C<$attribute_name>, +if none is found, it will return undef. =item B -This will remove the attribute meta-object stored at -C<$attribute_name>, then return the removed attribute meta-object. +This will remove the attribute meta-object stored at +C<$attribute_name>, then return the removed attribute meta-object. -B -Removing an attribute will only affect future instances of -the class, it will not make any attempt to remove the attribute from +B +Removing an attribute will only affect future instances of +the class, it will not make any attempt to remove the attribute from any existing instances of the class. -It should be noted that any accessor, reader/writer or predicate -methods which the attribute meta-object stored at C<$attribute_name> -has will be removed from the class at this time. This B make -these attributes somewhat inaccessable in previously created -instances. But if you are crazy enough to do this at runtime, then +It should be noted that any accessor, reader/writer or predicate +methods which the attribute meta-object stored at C<$attribute_name> +has will be removed from the class at this time. This B make +these attributes somewhat inaccessable in previously created +instances. But if you are crazy enough to do this at runtime, then you are crazy enough to deal with something like this :). =item B -This returns a list of attribute names which are defined in the local -class. If you want a list of all applicable attributes for a class, +This returns a list of attribute names which are defined in the local +class. If you want a list of all applicable attributes for a class, use the C method. =item B -This will traverse the inheritance heirachy and return a list of all -the applicable attributes for this class. It does not construct a -HASH reference like C because all -that same information is discoverable through the attribute +This will traverse the inheritance heirachy and return a list of all +the applicable attributes for this class. It does not construct a +HASH reference like C because all +that same information is discoverable through the attribute meta-object itself. =item B -This method will traverse the inheritance heirachy and find the -first attribute whose name matches C<$attr_name>, then return it. +This method will traverse the inheritance heirachy and find the +first attribute whose name matches C<$attr_name>, then return it. It will return undef if nothing is found. =back @@ -1331,10 +1577,19 @@ It will return undef if nothing is found. =item B -This method will invoke a tranforamtion upon the class which will -make it immutable. Details of this transformation can be found in +This method will invoke a tranforamtion upon the class which will +make it immutable. Details of this transformation can be found in the L documentation. +=item B + +This method will reverse tranforamtion upon the class which +made it immutable. + +=item B + +Create a transformer suitable for making this class immutable + =back =head1 AUTHORS @@ -1343,11 +1598,11 @@ Stevan Little Estevan@iinteractive.comE =head1 COPYRIGHT AND LICENSE -Copyright 2006, 2007 by Infinity Interactive, Inc. +Copyright 2006-2008 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. +it under the same terms as Perl itself. =cut