package MooseX::Object::Pluggable;
use Carp;
-use strict;
-use warnings;
use Moose::Role;
-use Class::Inspector;
+use Class::MOP;
+use Module::Pluggable::Object;
-
-our $VERSION = '0.0002';
+our $VERSION = '0.0009';
=head1 NAME
package MyApp;
use Moose;
-
+
with 'MooseX::Object::Pluggable';
...
=head1 DESCRIPTION
This module is meant to be loaded as a role from Moose-based classes
-it will add five methods and five attributes to assist you with the loading
+it will add five methods and four attributes to assist you with the loading
and handling of plugins and extensions for plugins. I understand that this may
pollute your namespace, however I took great care in using the least ambiguous
names possible.
their consuming classes, so it is important to watch for load order as plugins can
and will overload each other. You may also add attributes through has.
-Even thouch C<override> will work in basic cases, I STRONGLY discourage it's use
+Please note that when you load at runtime you lose the ability to wrap C<BUILD>
+and roles using C<has> will not go through compile time checks like C<required>
+and <default>.
+
+Even though C<override> will work , I STRONGLY discourage it's use
and a warning will be thrown if you try to use it.
-This is closely linked to the way multiple roles being applies is handles and is not
+This is closely linked to the way multiple roles being applied is handled and is not
likely to change. C<override> bevavior is closely linked to inheritance and thus will
likely not work as you expect it in multiple inheritance situations. Point being,
save yourself the headache.
=head1 How plugins are loaded
-You don't really need to understand anything except for the first paragraph.
-
-The first time you load a plugin a new anonymous L<Moose::Meta::Class> will be
-created. This class will inherit from your pluggable object and then your object
-will be reblessed to an instance of this anonymous class. This means that
+When roles are applied at runtime an anonymous class will wrap your class and
C<$self-E<gt>blessed> and C<ref $self> will no longer return the name of your object,
-they will instead return the name of the anonymous class created at runtime. Your
-original class name can be located at C<($self-E<gt>meta-E<gt>superclasses)[0]>
+they will instead return the name of the anonymous class created at runtime.
+See C<_original_class_name>.
-Once the anonymous subclass exists all plugin roles will be C<apply>ed to this class
-directly. This "subclass" though is in fact now C<$self> and it C<isa($yourclassname)>.
- If this is confusing.. it should be, thats why you let me handle it. Just know that it
-has to be done this way in order for plugins to override core functionality.
+=head1 Usage
-=head1
-
-For a simple example see the tests for this distribution.
+For a simple example see the tests included in this distribution.
=head1 Attributes
String. The prefix to use for plugin names provided. MyApp::Plugin is sensible.
-=head2 _plugin_ext
-
-Boolean. Indicates whether we should attempt to load plugin extensions.
-Defaults to true;
-
-=head2 _plugin_ext_ns
+=head2 _plugin_app_ns
-String. The namespace plugin extensions have. Defaults to 'ExtensionFor'.
+ArrayRef, Accessor automatically dereferences into array on a read call.
+By default will be filled with the class name and it's prescedents, it is used
+to determine which directories to look for plugins as well as which plugins
+take presedence upon namespace collitions. This allows you to subclass a pluggable
+class and still use it's plugins while using yours first if they are available.
-This means that is _plugin_ns is "MyApp::Plugin" and _plugin_ext_ns is
-"ExtensionFor" loading plugin "Bar" would search for extensions in
-"MyApp::Plugin::Bar::ExtensionFor::*".
-
-=head2 _plugin_loaded
-
-HashRef. Keeps an inventory of what plugins are loaded and what the actual
-module name is to avoid multiple loading.
+=cut
-=head2 __plugin_subclass
+=head2 _plugin_locator
-Object. This holds the subclass of our pluggable object in the form of an
-anonymous L<Moose::Meta::Class> instance. All roles are actually applied to
-this instance instead of the original class instance in order to not lose
-the original object name as roles are applied. The anonymous class will be
-automatically generated upon first use.
+An automatically built instance of L<Module::Pluggable::Object> used to locate
+available plugins.
=cut
#--------#---------#---------#---------#---------#---------#---------#---------#
-has _plugin_ns => (is => 'rw', required => 1, isa => 'Str',
- default => 'Plugin');
-
-has _plugin_ext => (is => 'rw', required => 1, isa => 'Bool',
- default => 1);
-has _plugin_ext_ns => (is => 'rw', required => 1, isa => 'Str',
- default => 'ExtensionFor');
-has _plugin_loaded => (is => 'rw', required => 1, isa => 'HashRef',
- default => sub{ {} });
-
-has __plugin_subclass => ( is => 'rw', required => 0, isa => 'Object', );
+has _plugin_ns =>
+ (
+ is => 'rw',
+ required => 1,
+ isa => 'Str',
+ default => sub{ 'Plugin' },
+ );
+
+has _plugin_loaded =>
+ (
+ is => 'rw',
+ required => 1,
+ isa => 'HashRef',
+ default => sub{ {} }
+ );
+
+has _plugin_app_ns =>
+ (
+ is => 'rw',
+ required => 1,
+ isa => 'ArrayRef',
+ lazy => 1,
+ auto_deref => 1,
+ builder => '_build_plugin_app_ns',
+ trigger => sub{ $_[0]->_clear_plugin_locator if $_[0]->_has_plugin_locator; },
+ );
+
+has _plugin_locator =>
+ (
+ is => 'rw',
+ required => 1,
+ lazy => 1,
+ isa => 'Module::Pluggable::Object',
+ clearer => '_clear_plugin_locator',
+ predicate => '_has_plugin_locator',
+ builder => '_build_plugin_locator'
+ );
#--------#---------#---------#---------#---------#---------#---------#---------#
=head1 Public Methods
+=head2 load_plugins @plugins
+
=head2 load_plugin $plugin
-This is the only method you should be using.
-Load the apropriate role for C<$plugin> as well as any
-extensions it provides if extensions are enabled.
+Load the apropriate role for C<$plugin>.
=cut
-sub load_plugin{
- my ($self, $plugin) = @_;
- die("You must provide a plugin name") unless $plugin;
+sub load_plugins {
+ my ($self, @plugins) = @_;
+ die("You must provide a plugin name") unless @plugins;
my $loaded = $self->_plugin_loaded;
- return 1 if exists $loaded->{$plugin};
-
- my $role = $self->_role_from_plugin($plugin);
+ my @load = grep { not exists $loaded->{$_} } @plugins;
+ my @roles = map { $self->_role_from_plugin($_) } @load;
+
+ if ( $self->_load_and_apply_role(@roles) ) {
+ @{ $loaded }{@load} = @roles;
+ return 1;
+ } else {
+ return;
+ }
+}
- $loaded->{$plugin} = $role if $self->_load_and_apply_role($role);
- $self->load_plugin_ext($plugin) if $self->_plugin_ext;
- return exists $loaded->{$plugin};
+sub load_plugin {
+ my $self = shift;
+ $self->load_plugins(@_);
}
+=head2 _original_class_name
-=head2 _load_plugin_ext
-
-Will load any extensions for a particular plugin. This should be called
-automatically by C<load_plugin> so you don't need to worry about it.
-It basically attempts to load any extension that exists for a plugin
-that is already loaded. The only reason for using this is if you want to
-keep _plugin_ext as false and only load extensions manually, which I don't
-recommend.
+Because of the way roles apply C<$self-E<gt>blessed> and C<ref $self> will
+no longer return what you expect. Instead use this class to get your original
+class name.
=cut
-sub load_plugin_ext{
- my ($self, $plugin) = @_;
- die("You must provide a plugin name") unless $plugin;
- my $role = $self->_role_from_plugin($plugin);
-
- # $p for plugin, $r for role
- while( my($p,$r) = each %{ $self->_plugin_loaded }){
- my $ext = join "::", $role, $self->_plugin_ext_ns, $p;
-
- $self->_load_and_apply_role( $ext )
- if Class::Inspector->installed($ext);
-
- #go back to prev loaded modules and load extensions for current module?
- #my $ext2 = join "::", $r, $self->_plugin_ext_ns, $plugin;
- #$self->_load_and_apply_role( $ext2 )
- # if Class::Inspector->installed($ext2);
- }
+sub _original_class_name{
+ my $self = shift;
+ return (grep {$_ !~ /^Moose::/} $self->meta->class_precedence_list)[0];
}
-=head1 Private Methods
-
-There's nothing stopping you from using these, but if you are using them
-you are probably doing something wrong.
-=head2 _plugin_subclass
-
-Creates, if needed and returns the anonymous instance of the consuming objects
-subclass to which roles will be applied to.
-
-=cut
+=head1 Private Methods
-sub _plugin_subclass{
- my $self = shift;
- my $anon_class = $self->__plugin_subclass;
-
- #initialize if we havnt been initialized already.
- unless(ref $anon_class && $self->meta->is_anon_class){
-
- #create an anon class that inherits from $self that plugins can be
- #applied to safely and store it within the $self instance.
- $anon_class = Moose::Meta::Class->
- create_anon_class(superclasses => [$self->meta->name]);
- $self->__plugin_subclass( $anon_class );
-
- #rebless $self as the anon class which now inherits from ourselves
- #this allows the anon class to override methods in the consuming
- #class while keeping a stable name and set of superclasses
- bless $self => $anon_class->name
- unless $self->meta->name eq $anon_class->name;
- }
-
- return $anon_class;
-}
+There's nothing stopping you from using these, but if you are using them
+for anything thats not really complicated you are probably doing
+something wrong.
=head2 _role_from_plugin $plugin
-Creates a role name from a plugin name. If the plugin name is prepended
+Creates a role name from a plugin name. If the plugin name is prepended
with a C<+> it will be treated as a full name returned as is. Otherwise
-a string consisting of C<$plugin> prepended with the application name
-and C<_plugin_ns> will be returned. Example
-
- #assuming appname MyApp and C<_plugin_ns> 'Plugin'
+a string consisting of C<$plugin> prepended with the C<_plugin_ns>
+and the first valid value from C<_plugin_app_ns> will be returned. Example
+
+ #assuming appname MyApp and C<_plugin_ns> 'Plugin'
$self->_role_from_plugin("MyPlugin"); # MyApp::Plugin::MyPlugin
=cut
sub _role_from_plugin{
my ($self, $plugin) = @_;
- my $name = $self->meta->is_anon_class ?
- ($self->meta->superclasses)[0] : $self->blessed;
+ return $1 if( $plugin =~ /^\+(.*)/ );
+
+ my $o = join '::', $self->_plugin_ns, $plugin;
+ #Father, please forgive me for I have sinned.
+ my @roles = grep{ /${o}$/ } $self->_plugin_locator->plugins;
+
+ croak("Unable to locate plugin '$plugin'") unless @roles;
+ return $roles[0] if @roles == 1;
- $plugin =~ /^\+(.*)/ ? $1 : join '::', $name, $self->_plugin_ns, $plugin;
+ my $i = 0;
+ my %presedence_list = map{ $i++; "${_}::${o}", $i } $self->_plugin_app_ns;
+
+ @roles = sort{ $presedence_list{$a} <=> $presedence_list{$b}} @roles;
+
+ return shift @roles;
}
-=head2 _load_and_apply_role $role
+=head2 _load_and_apply_role @roles
-Require C<$role> if it is not already loaded and apply it to
-C<_plugin_subclass>. This is the meat of this module.
+Require C<$role> if it is not already loaded and apply it. This is
+the meat of this module.
=cut
sub _load_and_apply_role{
- my ($self, $role) = @_;
- die("You must provide a role name") unless $role;
+ my ($self, @roles) = @_;
+ die("You must provide a role name") unless @roles;
- #Throw exception if plugin is not installed
- die("$role is not available on this system")
- unless Class::Inspector->installed($role);
+ foreach my $role ( @roles ) {
+ eval { Class::MOP::load_class($role) };
+ confess("Failed to load role: ${role} $@") if $@;
- #don't re-require...
- unless( Class::Inspector->loaded($role) ){
- eval "require $role" || die("Failed to load role: $role");
+ carp("Using 'override' is strongly discouraged and may not behave ".
+ "as you expect it to. Please use 'around'")
+ if scalar keys %{ $role->meta->get_override_method_modifiers_map };
}
- carp("Using 'override' is strongly discouraged and may not behave ".
- "as you expect it to. Please use 'around'")
- if scalar keys %{ $role->meta->get_override_method_modifiers_map };
-
- #apply the plugin to the anon subclass
- die("Failed to apply plugin: $role")
- unless $role->meta->apply( $self->_plugin_subclass );
+ Moose::Util::apply_all_roles( $self, @roles );
return 1;
}
+=head2 _build_plugin_app_ns
+
+Automatically builds the _plugin_app_ns attribute with the classes in the
+class presedence list that are not part of Moose.
+
+=cut
+
+sub _build_plugin_app_ns{
+ my $self = shift;
+ my @names = (grep {$_ !~ /^Moose::/} $self->meta->class_precedence_list);
+ return \@names;
+}
+
+=head2 _build_plugin_locator
+
+Automatically creates a L<Module::Pluggable::Object> instance with the correct
+search_path.
+
+=cut
+
+sub _build_plugin_locator{
+ my $self = shift;
+
+ my $locator = Module::Pluggable::Object->new
+ ( search_path =>
+ [ map { join '::', ($_, $self->_plugin_ns) } $self->_plugin_app_ns ]
+ );
+ return $locator;
+}
+
+=head2 meta
+
+Keep tests happy. See L<Moose>
+
+=cut
1;
=head1 SEE ALSO
-L<Moose>, L<Moose::Role>
+L<Moose>, L<Moose::Role>, L<Class::Inspector>
=head1 AUTHOR
projects / gitmo/MooseX-Object-Pluggable.git / blobdiff