named args for add_package_symbol
[gitmo/Package-Stash-PP.git] / lib / Package / Stash.pm
CommitLineData
e94260da 1package Package::Stash;
f10f6217 2use strict;
3use warnings;
4
5use Carp qw(confess);
6use Scalar::Util qw(reftype);
f4979588 7
8=head1 NAME
9
e94260da 10Package::Stash - routines for manipulating stashes
f4979588 11
12=head1 SYNOPSIS
13
e94260da 14 my $stash = Package::Stash->new('Foo');
683542f5 15 $stash->add_package_symbol('%foo', {bar => 1});
16 # $Foo::foo{bar} == 1
17 $stash->has_package_symbol('$foo') # false
18 my $namespace = $stash->namespace;
19 *{ $namespace->{foo} }{HASH} # {bar => 1}
f4979588 20
21=head1 DESCRIPTION
22
683542f5 23Manipulating stashes (Perl's symbol tables) is occasionally necessary, but
24incredibly messy, and easy to get wrong. This module hides all of that behind a
25simple API.
26
56a29840 27NOTE: Most methods in this class require a variable specification that includes
28a sigil. If this sigil is absent, it is assumed to represent the IO slot.
29
683542f5 30=head1 METHODS
31
32=cut
33
34=head2 new $package_name
35
e94260da 36Creates a new C<Package::Stash> object, for the package given as the only
683542f5 37argument.
f4979588 38
39=cut
40
f10f6217 41sub new {
42 my $class = shift;
43 my ($namespace) = @_;
60146e1c 44 return bless { 'package' => $namespace }, $class;
f10f6217 45}
46
683542f5 47=head2 name
48
49Returns the name of the package that this object represents.
50
51=cut
52
f10f6217 53sub name {
54 return $_[0]->{package};
55}
56
683542f5 57=head2 namespace
58
59Returns the raw stash itself.
60
61=cut
62
f10f6217 63sub namespace {
64 # NOTE:
65 # because of issues with the Perl API
66 # to the typeglob in some versions, we
67 # need to just always grab a new
68 # reference to the hash here. Ideally
69 # we could just store a ref and it would
70 # Just Work, but oh well :\
71 no strict 'refs';
72 return \%{$_[0]->name . '::'};
73}
74
75{
76 my %SIGIL_MAP = (
77 '$' => 'SCALAR',
78 '@' => 'ARRAY',
79 '%' => 'HASH',
80 '&' => 'CODE',
56a29840 81 '' => 'IO',
f10f6217 82 );
83
84 sub _deconstruct_variable_name {
85 my ($self, $variable) = @_;
86
56a29840 87 (defined $variable && length $variable)
f10f6217 88 || confess "You must pass a variable name";
89
90 my $sigil = substr($variable, 0, 1, '');
91
56a29840 92 if (exists $SIGIL_MAP{$sigil}) {
93 return ($variable, $sigil, $SIGIL_MAP{$sigil});
94 }
95 else {
96 return ("${sigil}${variable}", '', $SIGIL_MAP{''});
97 }
f10f6217 98 }
99}
100
4ada57e0 101=head2 add_package_symbol $variable $value $filename $firstlinenum $lastlinenum
683542f5 102
103Adds a new package symbol, for the symbol given as C<$variable>, and optionally
104gives it an initial value of C<$value>. C<$variable> should be the name of
105variable including the sigil, so
106
e94260da 107 Package::Stash->new('Foo')->add_package_symbol('%foo')
683542f5 108
109will create C<%Foo::foo>.
110
4ada57e0 111The optional $filename, $firstlinenum, and $lastlinenum arguments can be used
112to indicate where the symbol should be regarded as having been defined.
113Currently these values are only used if the symbol is a subroutine ('C<&>'
114sigil) and only if C<$^P & 0x10> is true. In which case the special
115C<%DB::sub> hash is updated to record the values of $filename, $firstlinenum,
116and $lastlinenum for the subroutine.
117
118This is especially useful for debuggers and profilers, which use C<%DB::sub> to
119determine where the source code for a subroutine can be found. See
120L<http://perldoc.perl.org/perldebguts.html#Debugger-Internals> for more
121information about C<%DB::sub>.
122
683542f5 123=cut
124
3634ce60 125sub _valid_for_type {
126 my $self = shift;
127 my ($value, $type) = @_;
128 if ($type eq 'HASH' || $type eq 'ARRAY'
129 || $type eq 'IO' || $type eq 'CODE') {
130 return reftype($value) eq $type;
131 }
132 else {
133 my $ref = reftype($value);
134 return !defined($ref) || $ref eq 'SCALAR' || $ref eq 'REF' || $ref eq 'LVALUE';
135 }
136}
137
f10f6217 138sub add_package_symbol {
640de369 139 my ($self, $variable, $initial_value, %opts) = @_;
f10f6217 140
141 my ($name, $sigil, $type) = ref $variable eq 'HASH'
142 ? @{$variable}{qw[name sigil type]}
143 : $self->_deconstruct_variable_name($variable);
144
4ada57e0 145 my $pkg = $self->name;
146
3634ce60 147 if (@_ > 2) {
148 $self->_valid_for_type($initial_value, $type)
149 || confess "$initial_value is not of type $type";
3634ce60 150
4ada57e0 151 # cheap fail-fast check for PERLDBf_SUBLINE and '&'
152 if ($^P and $^P & 0x10 && $sigil eq '&') {
640de369 153 my $filename = $opts{filename};
154 my $first_line_num = $opts{first_line_num};
4ada57e0 155
640de369 156 (undef, $filename, $first_line_num) = caller
4ada57e0 157 if not defined $filename;
640de369 158
159 my $last_line_num = $opts{last_line_num} || ($first_line_num ||= 0);
4ada57e0 160
161 # http://perldoc.perl.org/perldebguts.html#Debugger-Internals
640de369 162 $DB::sub{$pkg . '::' . $name} = "$filename:$first_line_num-$last_line_num";
4ada57e0 163 }
164 }
f10f6217 165
166 no strict 'refs';
167 no warnings 'redefine', 'misc', 'prototype';
168 *{$pkg . '::' . $name} = ref $initial_value ? $initial_value : \$initial_value;
169}
170
683542f5 171=head2 remove_package_glob $name
172
173Removes all package variables with the given name, regardless of sigil.
174
175=cut
176
f10f6217 177sub remove_package_glob {
178 my ($self, $name) = @_;
179 no strict 'refs';
180 delete ${$self->name . '::'}{$name};
181}
182
183# ... these functions deal with stuff on the namespace level
184
683542f5 185=head2 has_package_symbol $variable
186
187Returns whether or not the given package variable (including sigil) exists.
188
189=cut
190
f10f6217 191sub has_package_symbol {
192 my ($self, $variable) = @_;
193
194 my ($name, $sigil, $type) = ref $variable eq 'HASH'
195 ? @{$variable}{qw[name sigil type]}
196 : $self->_deconstruct_variable_name($variable);
197
198 my $namespace = $self->namespace;
199
200 return unless exists $namespace->{$name};
201
202 my $entry_ref = \$namespace->{$name};
203 if (reftype($entry_ref) eq 'GLOB') {
204 if ( $type eq 'SCALAR' ) {
205 return defined ${ *{$entry_ref}{SCALAR} };
206 }
207 else {
208 return defined *{$entry_ref}{$type};
209 }
210 }
211 else {
212 # a symbol table entry can be -1 (stub), string (stub with prototype),
213 # or reference (constant)
214 return $type eq 'CODE';
215 }
216}
217
683542f5 218=head2 get_package_symbol $variable
219
220Returns the value of the given package variable (including sigil).
221
222=cut
223
f10f6217 224sub get_package_symbol {
225 my ($self, $variable) = @_;
226
227 my ($name, $sigil, $type) = ref $variable eq 'HASH'
228 ? @{$variable}{qw[name sigil type]}
229 : $self->_deconstruct_variable_name($variable);
230
231 my $namespace = $self->namespace;
232
30d1a098 233 if (!exists $namespace->{$name}) {
b746972e 234 # assigning to the result of this function like
235 # @{$stash->get_package_symbol('@ISA')} = @new_ISA
236 # makes the result not visible until the variable is explicitly
237 # accessed... in the case of @ISA, this might never happen
238 # for instance, assigning like that and then calling $obj->isa
239 # will fail. see t/005-isa.t
240 if ($type eq 'ARRAY' && $name ne 'ISA') {
a2a2164a 241 $self->add_package_symbol($variable, []);
242 }
243 elsif ($type eq 'HASH') {
244 $self->add_package_symbol($variable, {});
245 }
246 else {
247 # FIXME
248 $self->add_package_symbol($variable)
249 }
30d1a098 250 }
f10f6217 251
252 my $entry_ref = \$namespace->{$name};
253
254 if (ref($entry_ref) eq 'GLOB') {
255 return *{$entry_ref}{$type};
256 }
257 else {
258 if ($type eq 'CODE') {
259 no strict 'refs';
260 return \&{ $self->name . '::' . $name };
261 }
262 else {
263 return undef;
264 }
265 }
266}
267
683542f5 268=head2 remove_package_symbol $variable
269
270Removes the package variable described by C<$variable> (which includes the
271sigil); other variables with the same name but different sigils will be
272untouched.
273
274=cut
275
f10f6217 276sub remove_package_symbol {
277 my ($self, $variable) = @_;
278
279 my ($name, $sigil, $type) = ref $variable eq 'HASH'
280 ? @{$variable}{qw[name sigil type]}
281 : $self->_deconstruct_variable_name($variable);
282
283 # FIXME:
284 # no doubt this is grossly inefficient and
285 # could be done much easier and faster in XS
286
b1a00d0e 287 my ($scalar_desc, $array_desc, $hash_desc, $code_desc, $io_desc) = (
f10f6217 288 { sigil => '$', type => 'SCALAR', name => $name },
289 { sigil => '@', type => 'ARRAY', name => $name },
290 { sigil => '%', type => 'HASH', name => $name },
291 { sigil => '&', type => 'CODE', name => $name },
b1a00d0e 292 { sigil => '', type => 'IO', name => $name },
f10f6217 293 );
294
b1a00d0e 295 my ($scalar, $array, $hash, $code, $io);
f10f6217 296 if ($type eq 'SCALAR') {
297 $array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc);
298 $hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc);
299 $code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc);
b1a00d0e 300 $io = $self->get_package_symbol($io_desc) if $self->has_package_symbol($io_desc);
f10f6217 301 }
302 elsif ($type eq 'ARRAY') {
42fa5cfc 303 $scalar = $self->get_package_symbol($scalar_desc);
f10f6217 304 $hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc);
305 $code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc);
b1a00d0e 306 $io = $self->get_package_symbol($io_desc) if $self->has_package_symbol($io_desc);
f10f6217 307 }
308 elsif ($type eq 'HASH') {
42fa5cfc 309 $scalar = $self->get_package_symbol($scalar_desc);
f10f6217 310 $array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc);
311 $code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc);
b1a00d0e 312 $io = $self->get_package_symbol($io_desc) if $self->has_package_symbol($io_desc);
f10f6217 313 }
314 elsif ($type eq 'CODE') {
42fa5cfc 315 $scalar = $self->get_package_symbol($scalar_desc);
f10f6217 316 $array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc);
317 $hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc);
b1a00d0e 318 $io = $self->get_package_symbol($io_desc) if $self->has_package_symbol($io_desc);
319 }
320 elsif ($type eq 'IO') {
42fa5cfc 321 $scalar = $self->get_package_symbol($scalar_desc);
b1a00d0e 322 $array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc);
323 $hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc);
324 $code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc);
f10f6217 325 }
326 else {
327 confess "This should never ever ever happen";
328 }
329
330 $self->remove_package_glob($name);
331
42fa5cfc 332 $self->add_package_symbol($scalar_desc => $scalar);
f10f6217 333 $self->add_package_symbol($array_desc => $array) if defined $array;
334 $self->add_package_symbol($hash_desc => $hash) if defined $hash;
335 $self->add_package_symbol($code_desc => $code) if defined $code;
b1a00d0e 336 $self->add_package_symbol($io_desc => $io) if defined $io;
f10f6217 337}
338
683542f5 339=head2 list_all_package_symbols $type_filter
340
341Returns a list of package variable names in the package, without sigils. If a
342C<type_filter> is passed, it is used to select package variables of a given
343type, where valid types are the slots of a typeglob ('SCALAR', 'CODE', 'HASH',
344etc).
345
346=cut
347
f10f6217 348sub list_all_package_symbols {
349 my ($self, $type_filter) = @_;
350
351 my $namespace = $self->namespace;
352 return keys %{$namespace} unless defined $type_filter;
353
354 # NOTE:
355 # or we can filter based on
356 # type (SCALAR|ARRAY|HASH|CODE)
357 if ($type_filter eq 'CODE') {
358 return grep {
359 (ref($namespace->{$_})
360 ? (ref($namespace->{$_}) eq 'SCALAR')
361 : (ref(\$namespace->{$_}) eq 'GLOB'
362 && defined(*{$namespace->{$_}}{CODE})));
363 } keys %{$namespace};
364 } else {
365 return grep { *{$namespace->{$_}}{$type_filter} } keys %{$namespace};
366 }
367}
f4979588 368
369=head1 BUGS
370
371No known bugs.
372
373Please report any bugs through RT: email
e94260da 374C<bug-package-stash at rt.cpan.org>, or browse to
375L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Package-Stash>.
f4979588 376
377=head1 SEE ALSO
378
683542f5 379L<Class::MOP::Package> - this module is a factoring out of code that used to
380live here
f4979588 381
382=head1 SUPPORT
383
384You can find this documentation for this module with the perldoc command.
385
e94260da 386 perldoc Package::Stash
f4979588 387
388You can also look for information at:
389
390=over 4
391
392=item * AnnoCPAN: Annotated CPAN documentation
393
e94260da 394L<http://annocpan.org/dist/Package-Stash>
f4979588 395
396=item * CPAN Ratings
397
e94260da 398L<http://cpanratings.perl.org/d/Package-Stash>
f4979588 399
400=item * RT: CPAN's request tracker
401
e94260da 402L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Package-Stash>
f4979588 403
404=item * Search CPAN
405
e94260da 406L<http://search.cpan.org/dist/Package-Stash>
f4979588 407
408=back
409
410=head1 AUTHOR
411
412 Jesse Luehrs <doy at tozt dot net>
413
683542f5 414Mostly copied from code from L<Class::MOP::Package>, by Stevan Little and the
415Moose Cabal.
416
f4979588 417=head1 COPYRIGHT AND LICENSE
418
419This software is copyright (c) 2010 by Jesse Luehrs.
420
421This is free software; you can redistribute it and/or modify it under
422the same terms as perl itself.
423
424=cut
425
4261;