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1 | |
2 | package Class::MOP::Package; |
3 | |
4 | use strict; |
5 | use warnings; |
6 | |
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7 | use Scalar::Util 'blessed', 'reftype', 'weaken'; |
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8 | use Carp 'confess'; |
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9 | use Devel::GlobalDestruction 'in_global_destruction'; |
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10 | use Package::Stash; |
11 | |
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12 | use base 'Class::MOP::Object'; |
13 | |
14 | # creation ... |
15 | |
16 | sub initialize { |
17 | my ( $class, @args ) = @_; |
18 | |
19 | unshift @args, "package" if @args % 2; |
20 | |
21 | my %options = @args; |
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22 | my $package_name = delete $options{package}; |
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23 | |
24 | |
25 | # we hand-construct the class |
26 | # until we can bootstrap it |
27 | if ( my $meta = Class::MOP::get_metaclass_by_name($package_name) ) { |
28 | return $meta; |
29 | } else { |
30 | my $meta = ( ref $class || $class )->_new({ |
31 | 'package' => $package_name, |
32 | %options, |
33 | }); |
34 | Class::MOP::store_metaclass_by_name($package_name, $meta); |
35 | |
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36 | Class::MOP::weaken_metaclass($package_name) if $options{weaken}; |
37 | |
38 | |
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39 | return $meta; |
40 | } |
41 | } |
42 | |
43 | sub reinitialize { |
44 | my ( $class, @args ) = @_; |
45 | |
46 | unshift @args, "package" if @args % 2; |
47 | |
48 | my %options = @args; |
49 | my $package_name = delete $options{package}; |
50 | |
51 | (defined $package_name && $package_name |
52 | && (!blessed $package_name || $package_name->isa('Class::MOP::Package'))) |
53 | || confess "You must pass a package name or an existing Class::MOP::Package instance"; |
54 | |
55 | $package_name = $package_name->name |
56 | if blessed $package_name; |
57 | |
58 | Class::MOP::remove_metaclass_by_name($package_name); |
59 | |
60 | $class->initialize($package_name, %options); # call with first arg form for compat |
61 | } |
62 | |
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63 | sub create { |
64 | my $class = shift; |
65 | my @args = @_; |
66 | |
67 | return $class->initialize(@args); |
68 | } |
69 | |
70 | ## ANON packages |
71 | |
72 | { |
73 | # NOTE: |
74 | # this should be sufficient, if you have a |
75 | # use case where it is not, write a test and |
76 | # I will change it. |
77 | my $ANON_SERIAL = 0; |
78 | |
79 | my %ANON_PACKAGE_CACHE; |
80 | |
81 | # NOTE: |
82 | # we need a sufficiently annoying prefix |
83 | # this should suffice for now, this is |
84 | # used in a couple of places below, so |
85 | # need to put it up here for now. |
86 | sub _anon_package_prefix { 'Class::MOP::Package::__ANON__::SERIAL::' } |
87 | |
88 | sub is_anon { |
89 | my $self = shift; |
90 | no warnings 'uninitialized'; |
91 | my $prefix = $self->_anon_package_prefix; |
92 | $self->name =~ /^$prefix/; |
93 | } |
94 | |
95 | sub create_anon { |
96 | my ($class, %options) = @_; |
97 | |
98 | my $cache_ok = delete $options{cache}; |
99 | |
100 | my $cache_key = $class->_anon_cache_key(%options); |
101 | |
102 | if ($cache_ok && defined $ANON_PACKAGE_CACHE{$cache_key}) { |
103 | return $ANON_PACKAGE_CACHE{$cache_key}; |
104 | } |
105 | |
106 | $options{weaken} = !$cache_ok unless exists $options{weaken}; |
107 | |
108 | my $package_name = $class->_anon_package_prefix . ++$ANON_SERIAL; |
109 | |
110 | my $meta = $class->create($package_name, %options); |
111 | |
112 | if ($cache_ok) { |
113 | $ANON_PACKAGE_CACHE{$cache_key} = $meta; |
114 | weaken($ANON_PACKAGE_CACHE{$cache_key}); |
115 | } |
116 | |
117 | return $meta; |
118 | } |
119 | |
120 | sub _anon_cache_key { confess "Packages are not cacheable" } |
121 | |
122 | sub DESTROY { |
123 | my $self = shift; |
124 | |
125 | return if in_global_destruction(); # it'll happen soon anyway and this just makes things more complicated |
126 | |
127 | $self->_free_anon |
128 | if $self->is_anon; |
129 | } |
130 | |
131 | sub _free_anon { |
132 | my $self = shift; |
133 | my $name = $self->name; |
134 | |
135 | # Moose does a weird thing where it replaces the metaclass for |
136 | # class when fixing metaclass incompatibility. In that case, |
137 | # we don't want to clean out the namespace now. We can detect |
138 | # that because Moose will explicitly update the singleton |
139 | # cache in Class::MOP. |
140 | no warnings 'uninitialized'; |
141 | my $current_meta = Class::MOP::get_metaclass_by_name($name); |
142 | return if $current_meta ne $self; |
143 | |
144 | my ($first_fragments, $last_fragment) = ($name =~ /^(.*)::(.*)$/); |
145 | |
146 | no strict 'refs'; |
147 | @{$name . '::ISA'} = (); |
148 | %{$name . '::'} = (); |
149 | delete ${$first_fragments . '::'}{$last_fragment . '::'}; |
150 | |
151 | Class::MOP::remove_metaclass_by_name($name); |
152 | } |
153 | |
154 | } |
155 | |
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156 | sub _new { |
157 | my $class = shift; |
158 | |
159 | return Class::MOP::Class->initialize($class)->new_object(@_) |
160 | if $class ne __PACKAGE__; |
161 | |
162 | my $params = @_ == 1 ? $_[0] : {@_}; |
163 | |
164 | return bless { |
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165 | # Need to quote package to avoid a problem with PPI mis-parsing this |
166 | # as a package statement. |
167 | 'package' => $params->{package}, |
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168 | |
169 | # NOTE: |
170 | # because of issues with the Perl API |
171 | # to the typeglob in some versions, we |
172 | # need to just always grab a new |
173 | # reference to the hash in the accessor. |
174 | # Ideally we could just store a ref and |
175 | # it would Just Work, but oh well :\ |
176 | |
177 | namespace => \undef, |
178 | |
179 | } => $class; |
180 | } |
181 | |
182 | # Attributes |
183 | |
184 | # NOTE: |
185 | # all these attribute readers will be bootstrapped |
186 | # away in the Class::MOP bootstrap section |
187 | |
188 | sub _package_stash { |
189 | $_[0]->{_package_stash} ||= Package::Stash->new($_[0]->name) |
190 | } |
191 | sub namespace { |
192 | $_[0]->_package_stash->namespace |
193 | } |
194 | |
195 | # Class attributes |
196 | |
197 | # ... these functions have to touch the symbol table itself,.. yuk |
198 | |
199 | sub add_package_symbol { |
200 | my $self = shift; |
201 | $self->_package_stash->add_symbol(@_); |
202 | } |
203 | |
204 | sub remove_package_glob { |
205 | my $self = shift; |
206 | $self->_package_stash->remove_glob(@_); |
207 | } |
208 | |
209 | # ... these functions deal with stuff on the namespace level |
210 | |
211 | sub has_package_symbol { |
212 | my $self = shift; |
213 | $self->_package_stash->has_symbol(@_); |
214 | } |
215 | |
216 | sub get_package_symbol { |
217 | my $self = shift; |
218 | $self->_package_stash->get_symbol(@_); |
219 | } |
220 | |
221 | sub get_or_add_package_symbol { |
222 | my $self = shift; |
223 | $self->_package_stash->get_or_add_symbol(@_); |
224 | } |
225 | |
226 | sub remove_package_symbol { |
227 | my $self = shift; |
228 | $self->_package_stash->remove_symbol(@_); |
229 | } |
230 | |
231 | sub list_all_package_symbols { |
232 | my $self = shift; |
233 | $self->_package_stash->list_all_symbols(@_); |
234 | } |
235 | |
236 | sub get_all_package_symbols { |
237 | my $self = shift; |
238 | $self->_package_stash->get_all_symbols(@_); |
239 | } |
240 | |
241 | 1; |
242 | |
243 | # ABSTRACT: Package Meta Object |
244 | |
245 | __END__ |
246 | |
247 | =pod |
248 | |
249 | =head1 DESCRIPTION |
250 | |
251 | The Package Protocol provides an abstraction of a Perl 5 package. A |
252 | package is basically namespace, and this module provides methods for |
253 | looking at and changing that namespace's symbol table. |
254 | |
255 | =head1 METHODS |
256 | |
257 | =over 4 |
258 | |
259 | =item B<< Class::MOP::Package->initialize($package_name) >> |
260 | |
261 | This method creates a new C<Class::MOP::Package> instance which |
262 | represents specified package. If an existing metaclass object exists |
263 | for the package, that will be returned instead. |
264 | |
265 | =item B<< Class::MOP::Package->reinitialize($package) >> |
266 | |
267 | This method forcibly removes any existing metaclass for the package |
268 | before calling C<initialize>. In contrast to C<initialize>, you may |
269 | also pass an existing C<Class::MOP::Package> instance instead of just |
270 | a package name as C<$package>. |
271 | |
272 | Do not call this unless you know what you are doing. |
273 | |
274 | =item B<< $metapackage->name >> |
275 | |
276 | This is returns the package's name, as passed to the constructor. |
277 | |
278 | =item B<< $metapackage->namespace >> |
279 | |
280 | This returns a hash reference to the package's symbol table. The keys |
281 | are symbol names and the values are typeglob references. |
282 | |
283 | =item B<< $metapackage->add_package_symbol($variable_name, $initial_value) >> |
284 | |
285 | This method accepts a variable name and an optional initial value. The |
286 | C<$variable_name> must contain a leading sigil. |
287 | |
288 | This method creates the variable in the package's symbol table, and |
289 | sets it to the initial value if one was provided. |
290 | |
291 | =item B<< $metapackage->get_package_symbol($variable_name) >> |
292 | |
293 | Given a variable name, this method returns the variable as a reference |
294 | or undef if it does not exist. The C<$variable_name> must contain a |
295 | leading sigil. |
296 | |
297 | =item B<< $metapackage->get_or_add_package_symbol($variable_name) >> |
298 | |
299 | Given a variable name, this method returns the variable as a reference. |
300 | If it does not exist, a default value will be generated if possible. The |
301 | C<$variable_name> must contain a leading sigil. |
302 | |
303 | =item B<< $metapackage->has_package_symbol($variable_name) >> |
304 | |
305 | Returns true if there is a package variable defined for |
306 | C<$variable_name>. The C<$variable_name> must contain a leading sigil. |
307 | |
308 | =item B<< $metapackage->remove_package_symbol($variable_name) >> |
309 | |
310 | This will remove the package variable specified C<$variable_name>. The |
311 | C<$variable_name> must contain a leading sigil. |
312 | |
313 | =item B<< $metapackage->remove_package_glob($glob_name) >> |
314 | |
315 | Given the name of a glob, this will remove that glob from the |
316 | package's symbol table. Glob names do not include a sigil. Removing |
317 | the glob removes all variables and subroutines with the specified |
318 | name. |
319 | |
320 | =item B<< $metapackage->list_all_package_symbols($type_filter) >> |
321 | |
322 | This will list all the glob names associated with the current |
323 | package. These names do not have leading sigils. |
324 | |
325 | You can provide an optional type filter, which should be one of |
326 | 'SCALAR', 'ARRAY', 'HASH', or 'CODE'. |
327 | |
328 | =item B<< $metapackage->get_all_package_symbols($type_filter) >> |
329 | |
330 | This works much like C<list_all_package_symbols>, but it returns a |
331 | hash reference. The keys are glob names and the values are references |
332 | to the value for that name. |
333 | |
334 | =item B<< Class::MOP::Package->meta >> |
335 | |
336 | This will return a L<Class::MOP::Class> instance for this class. |
337 | |
338 | =back |
339 | |
340 | =cut |