X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FRole%2FTiny.pm;h=a99c90ae7e7645933435ad6eaaec9ce30490003c;hb=c334a5c17366c11619fa319233059854491de274;hp=337c25d84fd513808d45a18b4ebe106cd9678197;hpb=a16d301ee1659572170ed6baebb3f5e2451b35f5;p=gitmo%2FRole-Tiny.git diff --git a/lib/Role/Tiny.pm b/lib/Role/Tiny.pm index 337c25d..a99c90a 100644 --- a/lib/Role/Tiny.pm +++ b/lib/Role/Tiny.pm @@ -1,19 +1,53 @@ package Role::Tiny; -use strictures 1; -use Class::Tiny::_Utils; +sub _getglob { \*{$_[0]} } +sub _getstash { \%{"$_[0]::"} } + +use strict; +use warnings FATAL => 'all'; + +our $VERSION = '1.000000'; # 1.0.0 +$VERSION = eval $VERSION; our %INFO; our %APPLIED_TO; +our %COMPOSED; + +# Module state workaround totally stolen from Zefram's Module::Runtime. + +BEGIN { + *_WORK_AROUND_BROKEN_MODULE_STATE = "$]" < 5.009 ? sub(){1} : sub(){0}; +} + +sub Role::Tiny::__GUARD__::DESTROY { + delete $INC{$_[0]->[0]} if @{$_[0]}; +} + +sub _load_module { + (my $proto = $_[0]) =~ s/::/\//g; + $proto .= '.pm'; + return 1 if $INC{$proto}; + # can't just ->can('can') because a sub-package Foo::Bar::Baz + # creates a 'Baz::' key in Foo::Bar's symbol table + return 1 if grep !/::$/, keys %{_getstash($_[0])||{}}; + my $guard = _WORK_AROUND_BROKEN_MODULE_STATE + && bless([ $proto ], 'Role::Tiny::__GUARD__'); + require $proto; + pop @$guard if _WORK_AROUND_BROKEN_MODULE_STATE; + return 1; +} sub import { my $target = caller; + my $me = shift; strictures->import; + return if $INFO{$target}; # already exported into this package # get symbol table reference my $stash = do { no strict 'refs'; \%{"${target}::"} }; # install before/after/around subs foreach my $type (qw(before after around)) { *{_getglob "${target}::${type}"} = sub { + require Class::Method::Modifiers; push @{$INFO{$target}{modifiers}||=[]}, [ $type => @_ ]; }; } @@ -22,32 +56,133 @@ sub import { }; *{_getglob "${target}::with"} = sub { die "Only one role supported at a time by with" if @_ > 1; - Role::Tiny->apply_role_to_package($_[0], $target); - }; - *{_getglob "${target}::has"} = sub { - my ($name, %spec) = @_; - ($INFO{$target}{accessor_maker} ||= do { - require Method::Generate::Accessor; - Method::Generate::Accessor->new - })->generate_method($target, $name, \%spec); - $INFO{$target}{attributes}{$name} = \%spec; + $me->apply_role_to_package($target, $_[0]); }; - # grab all *non-constant* (ref eq 'SCALAR') subs present + # grab all *non-constant* (stash slot is not a scalarref) subs present # in the symbol table and store their refaddrs (no need to forcibly # inflate constant subs into real subs) - also add '' to here (this # is used later) @{$INFO{$target}{not_methods}={}}{ - '', map { *$_{CODE}||() } grep !(ref eq 'SCALAR'), values %$stash + '', map { *$_{CODE}||() } grep !ref($_), values %$stash } = (); # a role does itself $APPLIED_TO{$target} = { $target => undef }; } sub apply_role_to_package { - my ($class, $role, $to) = @_; + my ($me, $to, $role) = @_; + + _load_module($role); + die "This is apply_role_to_package" if ref($to); - die "Not a Role::Tiny" unless my $info = $INFO{$role}; - my $methods = $info->{methods} ||= do { + die "${role} is not a Role::Tiny" unless my $info = $INFO{$role}; + + $me->_check_requires($to, $role, @{$info->{requires}||[]}); + + $me->_install_methods($to, $role); + + $me->_install_modifiers($to, $info->{modifiers}); + + # only add does() method to classes and only if they don't have one + if (not $INFO{$to} and not $to->can('does')) { + *{_getglob "${to}::does"} = \&does_role; + } + + # copy our role list into the target's + @{$APPLIED_TO{$to}||={}}{keys %{$APPLIED_TO{$role}}} = (); +} + +sub apply_roles_to_object { + my ($me, $object, @roles) = @_; + die "No roles supplied!" unless @roles; + my $class = ref($object); + bless($object, $me->create_class_with_roles($class, @roles)); + $object; +} + +sub create_class_with_roles { + my ($me, $superclass, @roles) = @_; + + die "No roles supplied!" unless @roles; + + my $new_name = join( + '__WITH__', $superclass, my $compose_name = join '__AND__', @roles + ); + + return $new_name if $COMPOSED{class}{$new_name}; + + foreach my $role (@roles) { + _load_module($role); + die "${role} is not a Role::Tiny" unless my $info = $INFO{$role}; + } + + if ($] >= 5.010) { + require mro; + } else { + require MRO::Compat; + } + + my @composable = map $me->_composable_package_for($_), reverse @roles; + + *{_getglob("${new_name}::ISA")} = [ @composable, $superclass ]; + + my @info = map +($INFO{$_} ? $INFO{$_} : ()), @roles; + + $me->_check_requires( + $new_name, $compose_name, + do { my %h; @h{map @{$_->{requires}||[]}, @info} = (); keys %h } + ); + + *{_getglob "${new_name}::does"} = \&does_role unless $new_name->can('does'); + + @{$APPLIED_TO{$new_name}||={}}{ + map keys %{$APPLIED_TO{$_}}, @roles + } = (); + + $COMPOSED{class}{$new_name} = 1; + return $new_name; +} + +sub _composable_package_for { + my ($me, $role) = @_; + my $composed_name = 'Role::Tiny::_COMPOSABLE::'.$role; + return $composed_name if $COMPOSED{role}{$composed_name}; + $me->_install_methods($composed_name, $role); + my $base_name = $composed_name.'::_BASE'; + *{_getglob("${composed_name}::ISA")} = [ $base_name ]; + my $modifiers = $INFO{$role}{modifiers}||[]; + my @mod_base; + foreach my $modified ( + do { my %h; @h{map $_->[1], @$modifiers} = (); keys %h } + ) { + push @mod_base, "sub ${modified} { shift->next::method(\@_) }"; + } + { + local $@; + eval(my $code = join "\n", "package ${base_name};", @mod_base); + die "Evaling failed: $@\nTrying to eval:\n${code}" if $@; + } + $me->_install_modifiers($composed_name, $modifiers); + $COMPOSED{role}{$composed_name} = 1; + return $composed_name; +} + +sub _check_requires { + my ($me, $to, $name, @requires) = @_; + if (my @requires_fail = grep !$to->can($_), @requires) { + # role -> role, add to requires, role -> class, error out + if (my $to_info = $INFO{$to}) { + push @{$to_info->{requires}||=[]}, @requires_fail; + } else { + die "Can't apply ${name} to ${to} - missing ".join(', ', @requires_fail); + } + } +} + +sub _concrete_methods_of { + my ($me, $role) = @_; + my $info = $INFO{$role}; + $info->{methods} ||= do { # grab role symbol table my $stash = do { no strict 'refs'; \%{"${role}::"}}; my $not_methods = $info->{not_methods}; @@ -57,60 +192,230 @@ sub apply_role_to_package { my $code = *{$stash->{$_}}{CODE}; # rely on the '' key we added in import for "no code here" exists $not_methods->{$code||''} ? () : ($_ => $code) - } grep !(ref($stash->{$_}) eq 'SCALAR'), keys %$stash + } grep !ref($stash->{$_}), keys %$stash }; }; +} + +sub methods_provided_by { + my ($me, $role) = @_; + die "${role} is not a Role::Tiny" unless my $info = $INFO{$role}; + (keys %{$me->_concrete_methods_of($role)}, @{$info->{requires}||[]}); +} + +sub _install_methods { + my ($me, $to, $role) = @_; + + my $info = $INFO{$role}; + + my $methods = $me->_concrete_methods_of($role); + # grab target symbol table my $stash = do { no strict 'refs'; \%{"${to}::"}}; + # determine already extant methods of target my %has_methods; @has_methods{grep - +((ref($stash->{$_}) eq 'SCALAR') || (*{$stash->{$_}}{CODE})), + +(ref($stash->{$_}) || *{$stash->{$_}}{CODE}), keys %$stash } = (); - if (my @requires_fail - = grep !exists $has_methods{$_}, @{$info->{requires}||[]}) { - # role -> role, add to requires, role -> class, error out - if (my $to_info = $INFO{$to}) { - push @{$to_info->{requires}||=[]}, @requires_fail; - } else { - die "Can't apply ${role} to ${to} - missing ".join(', ', @requires_fail); - } - } - my @to_install = grep !exists $has_methods{$_}, keys %$methods; - foreach my $i (@to_install) { + foreach my $i (grep !exists $has_methods{$_}, keys %$methods) { no warnings 'once'; *{_getglob "${to}::${i}"} = $methods->{$i}; } +} - foreach my $modifier (@{$info->{modifiers}||[]}) { - _install_modifier($to, @{$modifier}); - } - - # only add does() method to classes and only if they don't have one - if (not $INFO{$to} and not $to->can('does')) { - ${_getglob "${to}::does"} = \&does_role; - } - - if (my $attr_info = $info->{attributes}) { - if ($INFO{$to}) { - @{$INFO{$to}{attributes}||={}}{keys %$attr_info} = values %$attr_info; - } else { - # only fiddle with the constructor if the target is a Class::Tiny class - if (my $con = Class::Tiny->_constructor_maker_for($to)) { - $con->register_attribute_specs(%$attr_info); - } +sub _install_modifiers { + my ($me, $to, $modifiers) = @_; + if (my $info = $INFO{$to}) { + push @{$info->{modifiers}}, @{$modifiers||[]}; + } else { + foreach my $modifier (@{$modifiers||[]}) { + $me->_install_single_modifier($to, @$modifier); } } +} - # copy our role list into the target's - @{$APPLIED_TO{$to}||={}}{keys %{$APPLIED_TO{$role}}} = (); +sub _install_single_modifier { + my ($me, @args) = @_; + Class::Method::Modifiers::install_modifier(@args); } sub does_role { - my ($package, $role) = @_; - return exists $APPLIED_TO{$package}{$role}; + my ($proto, $role) = @_; + return exists $APPLIED_TO{ref($proto)||$proto}{$role}; } 1; + +=head1 NAME + +Role::Tiny - Roles. Like a nouvelle cusine portion size slice of Moose. + +=head1 SYNOPSIS + + package Some::Role; + + use Role::Tiny; + + sub foo { ... } + + sub bar { ... } + + 1; + +else where + + package Some::Class; + + use Role::Tiny::With; + + # bar gets imported, but not foo + with 'Some::Role'; + + sub foo { ... } + + 1; + +=head1 DESCRIPTION + +C is a minimalist role composition tool. + +=head1 ROLE COMPOSITION + +Role composition can be thought of as much more clever and meaningful multiple +inheritance. The basics of this implementation of roles is: + +=over 2 + +=item * + +If a method is already defined on a class, that method will not be composed in +from the role. + +=item * + +If a method that the role L to be implemented is not implemented, +role application will fail loudly. + +=back + +Unlike L, where the B class inherited from "wins," role +composition is the other way around, where first wins. In a more complete +system (see L) roles are checked to see if they clash. The goal of this +is to be much simpler, hence disallowing composition of multiple roles at once. + +=head1 METHODS + +=head2 apply_role_to_package + + Role::Tiny->apply_role_to_package('Some::Package', 'Some::Role'); + +Composes role with package. See also L. + +=head2 apply_roles_to_object + + Role::Tiny->apply_roles_to_object($foo, qw(Some::Role1 Some::Role2)); + +Composes roles in order into object directly. Object is reblessed into the +resulting class. + +=head2 create_class_with_roles + + Role::Tiny->create_class_with_roles('Some::Base', qw(Some::Role1 Some::Role2)); + +Creates a new class based on base, with the roles composed into it in order. +New class is returned. + +=head1 SUBROUTINES + +=head2 does_role + + if (Role::Tiny::does_role($foo, 'Some::Role')) { + ... + } + +Returns true if class has been composed with role. + +This subroutine is also installed as ->does on any class a Role::Tiny is +composed into unless that class already has an ->does method, so + + if ($foo->does_role('Some::Role')) { + ... + } + +will work for classes but to test a role, one must use ::does_role directly + +=head1 IMPORTED SUBROUTINES + +=head2 requires + + requires qw(foo bar); + +Declares a list of methods that must be defined to compose role. + +=head2 with + + with 'Some::Role1'; + with 'Some::Role2'; + +Composes another role into the current role. Only one role may be composed in +at a time to allow the code to remain as simple as possible. + +=head2 before + + before foo => sub { ... }; + +See L<< Class::Method::Modifiers/before method(s) => sub { ... } >> for full +documentation. + +=head2 around + + around foo => sub { ... }; + +See L<< Class::Method::Modifiers/around method(s) => sub { ... } >> for full +documentation. + +=head2 after + + after foo => sub { ... }; + +See L<< Class::Method::Modifiers/after method(s) => sub { ... } >> for full +documentation. + +=head1 AUTHOR + +mst - Matt S. Trout (cpan:MSTROUT) + +=head1 CONTRIBUTORS + +dg - David Leadbeater (cpan:DGL) + +frew - Arthur Axel "fREW" Schmidt (cpan:FREW) + +hobbs - Andrew Rodland (cpan:ARODLAND) + +jnap - John Napiorkowski (cpan:JJNAPIORK) + +ribasushi - Peter Rabbitson (cpan:RIBASUSHI) + +chip - Chip Salzenberg (cpan:CHIPS) + +ajgb - Alex J. G. Burzyński (cpan:AJGB) + +doy - Jesse Luehrs (cpan:DOY) + +perigrin - Chris Prather (cpan:PERIGRIN) + +=head1 COPYRIGHT + +Copyright (c) 2010-2012 the Role::Tiny L and L +as listed above. + +=head1 LICENSE + +This library is free software and may be distributed under the same terms +as perl itself. + +=cut