Commit | Line | Data |
ab3370e7 |
1 | package Role::Tiny; |
2 | |
119014a7 |
3 | sub _getglob { \*{$_[0]} } |
5e03b55c |
4 | sub _getstash { \%{"$_[0]::"} } |
119014a7 |
5 | |
b1eebd55 |
6 | use strict; |
7 | use warnings FATAL => 'all'; |
ab3370e7 |
8 | |
9 | our %INFO; |
10 | our %APPLIED_TO; |
1947330a |
11 | our %COMPOSED; |
ab3370e7 |
12 | |
cf62c989 |
13 | # Module state workaround totally stolen from Zefram's Module::Runtime. |
14 | |
15 | BEGIN { |
16 | *_WORK_AROUND_BROKEN_MODULE_STATE = "$]" < 5.009 ? sub(){1} : sub(){0}; |
17 | } |
18 | |
19 | sub Role::Tiny::__GUARD__::DESTROY { |
20 | delete $INC{$_[0]->[0]} if @{$_[0]}; |
21 | } |
5e03b55c |
22 | |
fb5074f6 |
23 | sub _load_module { |
fb5074f6 |
24 | (my $proto = $_[0]) =~ s/::/\//g; |
cf62c989 |
25 | $proto .= '.pm'; |
26 | return 1 if $INC{$proto}; |
5e03b55c |
27 | # can't just ->can('can') because a sub-package Foo::Bar::Baz |
28 | # creates a 'Baz::' key in Foo::Bar's symbol table |
29 | return 1 if grep !/::$/, keys %{_getstash($_[0])||{}}; |
cf62c989 |
30 | my $guard = _WORK_AROUND_BROKEN_MODULE_STATE |
31 | && bless([ $proto ], 'Role::Tiny::__GUARD__'); |
32 | require $proto; |
33 | pop @$guard if _WORK_AROUND_BROKEN_MODULE_STATE; |
fb5074f6 |
34 | return 1; |
35 | } |
36 | |
ab3370e7 |
37 | sub import { |
38 | my $target = caller; |
a1164a0b |
39 | my $me = shift; |
de3d4906 |
40 | strictures->import; |
1ba11455 |
41 | return if $INFO{$target}; # already exported into this package |
ab3370e7 |
42 | # get symbol table reference |
43 | my $stash = do { no strict 'refs'; \%{"${target}::"} }; |
44 | # install before/after/around subs |
45 | foreach my $type (qw(before after around)) { |
5a247406 |
46 | *{_getglob "${target}::${type}"} = sub { |
7568ba55 |
47 | require Class::Method::Modifiers; |
ab3370e7 |
48 | push @{$INFO{$target}{modifiers}||=[]}, [ $type => @_ ]; |
49 | }; |
50 | } |
5a247406 |
51 | *{_getglob "${target}::requires"} = sub { |
ab3370e7 |
52 | push @{$INFO{$target}{requires}||=[]}, @_; |
53 | }; |
5a247406 |
54 | *{_getglob "${target}::with"} = sub { |
55 | die "Only one role supported at a time by with" if @_ > 1; |
369a4c50 |
56 | $me->apply_role_to_package($target, $_[0]); |
96d3f07a |
57 | }; |
7b8177f8 |
58 | # grab all *non-constant* (stash slot is not a scalarref) subs present |
ab3370e7 |
59 | # in the symbol table and store their refaddrs (no need to forcibly |
60 | # inflate constant subs into real subs) - also add '' to here (this |
61 | # is used later) |
62 | @{$INFO{$target}{not_methods}={}}{ |
faa9ce11 |
63 | '', map { *$_{CODE}||() } grep !ref($_), values %$stash |
ab3370e7 |
64 | } = (); |
65 | # a role does itself |
66 | $APPLIED_TO{$target} = { $target => undef }; |
67 | } |
68 | |
69 | sub apply_role_to_package { |
369a4c50 |
70 | my ($me, $to, $role) = @_; |
1947330a |
71 | |
fb5074f6 |
72 | _load_module($role); |
73 | |
ab3370e7 |
74 | die "This is apply_role_to_package" if ref($to); |
1947330a |
75 | die "${role} is not a Role::Tiny" unless my $info = $INFO{$role}; |
76 | |
77 | $me->_check_requires($to, $role, @{$info->{requires}||[]}); |
78 | |
79 | $me->_install_methods($to, $role); |
80 | |
81 | $me->_install_modifiers($to, $info->{modifiers}); |
82 | |
83 | # only add does() method to classes and only if they don't have one |
84 | if (not $INFO{$to} and not $to->can('does')) { |
85 | *{_getglob "${to}::does"} = \&does_role; |
86 | } |
87 | |
1947330a |
88 | # copy our role list into the target's |
89 | @{$APPLIED_TO{$to}||={}}{keys %{$APPLIED_TO{$role}}} = (); |
90 | } |
91 | |
92 | sub apply_roles_to_object { |
93 | my ($me, $object, @roles) = @_; |
94 | die "No roles supplied!" unless @roles; |
95 | my $class = ref($object); |
96 | bless($object, $me->create_class_with_roles($class, @roles)); |
97 | $object; |
98 | } |
99 | |
100 | sub create_class_with_roles { |
101 | my ($me, $superclass, @roles) = @_; |
102 | |
fb5074f6 |
103 | die "No roles supplied!" unless @roles; |
104 | |
c69190f1 |
105 | my $new_name = join( |
106 | '__WITH__', $superclass, my $compose_name = join '__AND__', @roles |
107 | ); |
108 | |
1947330a |
109 | return $new_name if $COMPOSED{class}{$new_name}; |
110 | |
111 | foreach my $role (@roles) { |
fb5074f6 |
112 | _load_module($role); |
1947330a |
113 | die "${role} is not a Role::Tiny" unless my $info = $INFO{$role}; |
114 | } |
115 | |
786e5ba0 |
116 | if ($] >= 5.010) { |
7568ba55 |
117 | require mro; |
b1eebd55 |
118 | } else { |
7568ba55 |
119 | require MRO::Compat; |
b1eebd55 |
120 | } |
1947330a |
121 | |
122 | my @composable = map $me->_composable_package_for($_), reverse @roles; |
123 | |
124 | *{_getglob("${new_name}::ISA")} = [ @composable, $superclass ]; |
125 | |
126 | my @info = map +($INFO{$_} ? $INFO{$_} : ()), @roles; |
127 | |
128 | $me->_check_requires( |
129 | $new_name, $compose_name, |
130 | do { my %h; @h{map @{$_->{requires}||[]}, @info} = (); keys %h } |
131 | ); |
1947330a |
132 | |
133 | *{_getglob "${new_name}::does"} = \&does_role unless $new_name->can('does'); |
134 | |
135 | @{$APPLIED_TO{$new_name}||={}}{ |
136 | map keys %{$APPLIED_TO{$_}}, @roles |
137 | } = (); |
138 | |
139 | $COMPOSED{class}{$new_name} = 1; |
140 | return $new_name; |
141 | } |
142 | |
143 | sub _composable_package_for { |
144 | my ($me, $role) = @_; |
145 | my $composed_name = 'Role::Tiny::_COMPOSABLE::'.$role; |
146 | return $composed_name if $COMPOSED{role}{$composed_name}; |
147 | $me->_install_methods($composed_name, $role); |
148 | my $base_name = $composed_name.'::_BASE'; |
149 | *{_getglob("${composed_name}::ISA")} = [ $base_name ]; |
150 | my $modifiers = $INFO{$role}{modifiers}||[]; |
b1eebd55 |
151 | my @mod_base; |
1947330a |
152 | foreach my $modified ( |
153 | do { my %h; @h{map $_->[1], @$modifiers} = (); keys %h } |
154 | ) { |
b1eebd55 |
155 | push @mod_base, "sub ${modified} { shift->next::method(\@_) }"; |
1947330a |
156 | } |
59812c87 |
157 | { |
158 | local $@; |
159 | eval(my $code = join "\n", "package ${base_name};", @mod_base); |
160 | die "Evaling failed: $@\nTrying to eval:\n${code}" if $@; |
161 | } |
1947330a |
162 | $me->_install_modifiers($composed_name, $modifiers); |
163 | $COMPOSED{role}{$composed_name} = 1; |
164 | return $composed_name; |
165 | } |
166 | |
167 | sub _check_requires { |
168 | my ($me, $to, $name, @requires) = @_; |
169 | if (my @requires_fail = grep !$to->can($_), @requires) { |
170 | # role -> role, add to requires, role -> class, error out |
171 | if (my $to_info = $INFO{$to}) { |
172 | push @{$to_info->{requires}||=[]}, @requires_fail; |
173 | } else { |
174 | die "Can't apply ${name} to ${to} - missing ".join(', ', @requires_fail); |
175 | } |
176 | } |
177 | } |
178 | |
4db3a740 |
179 | sub _concrete_methods_of { |
180 | my ($me, $role) = @_; |
1947330a |
181 | my $info = $INFO{$role}; |
4db3a740 |
182 | $info->{methods} ||= do { |
ab3370e7 |
183 | # grab role symbol table |
184 | my $stash = do { no strict 'refs'; \%{"${role}::"}}; |
185 | my $not_methods = $info->{not_methods}; |
186 | +{ |
187 | # grab all code entries that aren't in the not_methods list |
188 | map { |
934ea2c1 |
189 | my $code = *{$stash->{$_}}{CODE}; |
190 | # rely on the '' key we added in import for "no code here" |
191 | exists $not_methods->{$code||''} ? () : ($_ => $code) |
faa9ce11 |
192 | } grep !ref($stash->{$_}), keys %$stash |
ab3370e7 |
193 | }; |
194 | }; |
4db3a740 |
195 | } |
196 | |
197 | sub methods_provided_by { |
198 | my ($me, $role) = @_; |
199 | die "${role} is not a Role::Tiny" unless my $info = $INFO{$role}; |
200 | (keys %{$me->_concrete_methods_of($role)}, @{$info->{requires}||[]}); |
201 | } |
202 | |
203 | sub _install_methods { |
204 | my ($me, $to, $role) = @_; |
205 | |
206 | my $info = $INFO{$role}; |
207 | |
208 | my $methods = $me->_concrete_methods_of($role); |
1947330a |
209 | |
ab3370e7 |
210 | # grab target symbol table |
211 | my $stash = do { no strict 'refs'; \%{"${to}::"}}; |
1947330a |
212 | |
ab3370e7 |
213 | # determine already extant methods of target |
214 | my %has_methods; |
215 | @has_methods{grep |
faa9ce11 |
216 | +(ref($stash->{$_}) || *{$stash->{$_}}{CODE}), |
ab3370e7 |
217 | keys %$stash |
218 | } = (); |
ab3370e7 |
219 | |
1947330a |
220 | foreach my $i (grep !exists $has_methods{$_}, keys %$methods) { |
ab3370e7 |
221 | no warnings 'once'; |
5a247406 |
222 | *{_getglob "${to}::${i}"} = $methods->{$i}; |
ab3370e7 |
223 | } |
1947330a |
224 | } |
ab3370e7 |
225 | |
1947330a |
226 | sub _install_modifiers { |
227 | my ($me, $to, $modifiers) = @_; |
dccea57d |
228 | if (my $info = $INFO{$to}) { |
229 | push @{$info->{modifiers}}, @{$modifiers||[]}; |
230 | } else { |
231 | foreach my $modifier (@{$modifiers||[]}) { |
232 | $me->_install_single_modifier($to, @$modifier); |
233 | } |
96d3f07a |
234 | } |
ab3370e7 |
235 | } |
236 | |
dccea57d |
237 | sub _install_single_modifier { |
238 | my ($me, @args) = @_; |
239 | Class::Method::Modifiers::install_modifier(@args); |
240 | } |
241 | |
ab3370e7 |
242 | sub does_role { |
390ac406 |
243 | my ($proto, $role) = @_; |
244 | return exists $APPLIED_TO{ref($proto)||$proto}{$role}; |
ab3370e7 |
245 | } |
246 | |
247 | 1; |
5febcf4d |
248 | |
0b6e5fff |
249 | =head1 NAME |
250 | |
251 | Role::Tiny - Roles. Like a nouvelle cusine portion size slice of Moose. |
5febcf4d |
252 | |
253 | =head1 SYNOPSIS |
254 | |
255 | package Some::Role; |
256 | |
257 | use Role::Tiny; |
258 | |
259 | sub foo { ... } |
260 | |
261 | sub bar { ... } |
262 | |
263 | 1; |
264 | |
265 | else where |
266 | |
267 | package Some::Class; |
268 | |
a1164a0b |
269 | use Role::Tiny::With; |
5febcf4d |
270 | |
271 | # bar gets imported, but not foo |
a1164a0b |
272 | with 'Some::Role'; |
5febcf4d |
273 | |
274 | sub foo { ... } |
275 | |
276 | 1; |
277 | |
278 | =head1 DESCRIPTION |
279 | |
280 | C<Role::Tiny> is a minimalist role composition tool. |
281 | |
282 | =head1 ROLE COMPOSITION |
283 | |
284 | Role composition can be thought of as much more clever and meaningful multiple |
285 | inheritance. The basics of this implementation of roles is: |
286 | |
287 | =over 2 |
288 | |
289 | =item * |
290 | |
291 | If a method is already defined on a class, that method will not be composed in |
292 | from the role. |
293 | |
294 | =item * |
295 | |
296 | If a method that the role L</requires> to be implemented is not implemented, |
297 | role application will fail loudly. |
298 | |
0d39f9d3 |
299 | =back |
300 | |
5febcf4d |
301 | Unlike L<Class::C3>, where the B<last> class inherited from "wins," role |
302 | composition is the other way around, where first wins. In a more complete |
303 | system (see L<Moose>) roles are checked to see if they clash. The goal of this |
304 | is to be much simpler, hence disallowing composition of multiple roles at once. |
305 | |
306 | =head1 METHODS |
307 | |
308 | =head2 apply_role_to_package |
309 | |
369a4c50 |
310 | Role::Tiny->apply_role_to_package('Some::Package', 'Some::Role'); |
5febcf4d |
311 | |
a1164a0b |
312 | Composes role with package. See also L<Role::Tiny::With>. |
5febcf4d |
313 | |
314 | =head2 apply_roles_to_object |
315 | |
316 | Role::Tiny->apply_roles_to_object($foo, qw(Some::Role1 Some::Role2)); |
317 | |
318 | Composes roles in order into object directly. Object is reblessed into the |
319 | resulting class. |
320 | |
321 | =head2 create_class_with_roles |
322 | |
323 | Role::Tiny->create_class_with_roles('Some::Base', qw(Some::Role1 Some::Role2)); |
324 | |
325 | Creates a new class based on base, with the roles composed into it in order. |
326 | New class is returned. |
327 | |
54e4000d |
328 | =head1 SUBROUTINES |
5febcf4d |
329 | |
330 | =head2 does_role |
331 | |
54e4000d |
332 | if (Role::Tiny::does_role($foo, 'Some::Role')) { |
5febcf4d |
333 | ... |
334 | } |
335 | |
336 | Returns true if class has been composed with role. |
337 | |
54e4000d |
338 | This subroutine is also installed as ->does on any class a Role::Tiny is |
339 | composed into unless that class already has an ->does method, so |
340 | |
341 | if ($foo->does_role('Some::Role')) { |
342 | ... |
343 | } |
344 | |
345 | will work for classes but to test a role, one must use ::does_role directly |
346 | |
5febcf4d |
347 | =head1 IMPORTED SUBROUTINES |
348 | |
349 | =head2 requires |
350 | |
351 | requires qw(foo bar); |
352 | |
353 | Declares a list of methods that must be defined to compose role. |
354 | |
355 | =head2 with |
356 | |
357 | with 'Some::Role1'; |
358 | with 'Some::Role2'; |
359 | |
360 | Composes another role into the current role. Only one role may be composed in |
361 | at a time to allow the code to remain as simple as possible. |
362 | |
363 | =head2 before |
364 | |
365 | before foo => sub { ... }; |
366 | |
367 | See L<< Class::Method::Modifiers/before method(s) => sub { ... } >> for full |
368 | documentation. |
369 | |
370 | =head2 around |
371 | |
372 | around foo => sub { ... }; |
373 | |
374 | See L<< Class::Method::Modifiers/around method(s) => sub { ... } >> for full |
375 | documentation. |
376 | |
377 | =head2 after |
378 | |
379 | after foo => sub { ... }; |
380 | |
381 | See L<< Class::Method::Modifiers/after method(s) => sub { ... } >> for full |
382 | documentation. |
383 | |
40f3e3aa |
384 | =head1 AUTHORS |
385 | |
386 | See L<Moo> for authors. |
387 | |
388 | =head1 COPYRIGHT AND LICENSE |
389 | |
390 | See L<Moo> for the copyright and license. |
391 | |
392 | =cut |