make the ISA special-casing more sane
[gitmo/Package-Stash.git] / lib / Package / Stash.pm
CommitLineData
e94260da 1package Package::Stash;
f10f6217 2use strict;
3use warnings;
988beb41 4# ABSTRACT: routines for manipulating stashes
f10f6217 5
6use Carp qw(confess);
7use Scalar::Util qw(reftype);
f4979588 8
f4979588 9=head1 SYNOPSIS
10
e94260da 11 my $stash = Package::Stash->new('Foo');
683542f5 12 $stash->add_package_symbol('%foo', {bar => 1});
13 # $Foo::foo{bar} == 1
14 $stash->has_package_symbol('$foo') # false
15 my $namespace = $stash->namespace;
16 *{ $namespace->{foo} }{HASH} # {bar => 1}
f4979588 17
18=head1 DESCRIPTION
19
683542f5 20Manipulating stashes (Perl's symbol tables) is occasionally necessary, but
21incredibly messy, and easy to get wrong. This module hides all of that behind a
22simple API.
23
56a29840 24NOTE: Most methods in this class require a variable specification that includes
25a sigil. If this sigil is absent, it is assumed to represent the IO slot.
26
988beb41 27=method new $package_name
683542f5 28
e94260da 29Creates a new C<Package::Stash> object, for the package given as the only
683542f5 30argument.
f4979588 31
32=cut
33
f10f6217 34sub new {
35 my $class = shift;
e55970bc 36 my ($package) = @_;
37 my $namespace;
38 {
39 no strict 'refs';
40 # supposedly this caused a bug in earlier perls, but I can't reproduce
41 # it, so re-enabling the caching
42 $namespace = \%{$package . '::'};
43 }
44 return bless {
45 'package' => $package,
46 'namespace' => $namespace,
47 }, $class;
f10f6217 48}
49
988beb41 50=method name
683542f5 51
52Returns the name of the package that this object represents.
53
54=cut
55
f10f6217 56sub name {
57 return $_[0]->{package};
58}
59
988beb41 60=method namespace
683542f5 61
62Returns the raw stash itself.
63
64=cut
65
f10f6217 66sub namespace {
e55970bc 67 return $_[0]->{namespace};
f10f6217 68}
69
70{
71 my %SIGIL_MAP = (
72 '$' => 'SCALAR',
73 '@' => 'ARRAY',
74 '%' => 'HASH',
75 '&' => 'CODE',
56a29840 76 '' => 'IO',
f10f6217 77 );
78
79 sub _deconstruct_variable_name {
80 my ($self, $variable) = @_;
81
56a29840 82 (defined $variable && length $variable)
f10f6217 83 || confess "You must pass a variable name";
84
85 my $sigil = substr($variable, 0, 1, '');
86
56a29840 87 if (exists $SIGIL_MAP{$sigil}) {
88 return ($variable, $sigil, $SIGIL_MAP{$sigil});
89 }
90 else {
91 return ("${sigil}${variable}", '', $SIGIL_MAP{''});
92 }
f10f6217 93 }
94}
95
988beb41 96=method add_package_symbol $variable $value %opts
683542f5 97
98Adds a new package symbol, for the symbol given as C<$variable>, and optionally
99gives it an initial value of C<$value>. C<$variable> should be the name of
100variable including the sigil, so
101
e94260da 102 Package::Stash->new('Foo')->add_package_symbol('%foo')
683542f5 103
104will create C<%Foo::foo>.
105
c61010aa 106Valid options (all optional) are C<filename>, C<first_line_num>, and
107C<last_line_num>.
108
109C<$opts{filename}>, C<$opts{first_line_num}>, and C<$opts{last_line_num}> can
110be used to indicate where the symbol should be regarded as having been defined.
4ada57e0 111Currently these values are only used if the symbol is a subroutine ('C<&>'
c61010aa 112sigil) and only if C<$^P & 0x10> is true, in which case the special C<%DB::sub>
113hash is updated to record the values of C<filename>, C<first_line_num>, and
114C<last_line_num> for the subroutine. If these are not passed, their values are
115inferred (as much as possible) from C<caller> information.
4ada57e0 116
117This is especially useful for debuggers and profilers, which use C<%DB::sub> to
118determine where the source code for a subroutine can be found. See
119L<http://perldoc.perl.org/perldebguts.html#Debugger-Internals> for more
120information about C<%DB::sub>.
121
683542f5 122=cut
123
3634ce60 124sub _valid_for_type {
125 my $self = shift;
126 my ($value, $type) = @_;
127 if ($type eq 'HASH' || $type eq 'ARRAY'
128 || $type eq 'IO' || $type eq 'CODE') {
129 return reftype($value) eq $type;
130 }
131 else {
132 my $ref = reftype($value);
133 return !defined($ref) || $ref eq 'SCALAR' || $ref eq 'REF' || $ref eq 'LVALUE';
134 }
135}
136
f10f6217 137sub add_package_symbol {
640de369 138 my ($self, $variable, $initial_value, %opts) = @_;
f10f6217 139
140 my ($name, $sigil, $type) = ref $variable eq 'HASH'
141 ? @{$variable}{qw[name sigil type]}
142 : $self->_deconstruct_variable_name($variable);
143
4ada57e0 144 my $pkg = $self->name;
145
3634ce60 146 if (@_ > 2) {
147 $self->_valid_for_type($initial_value, $type)
148 || confess "$initial_value is not of type $type";
3634ce60 149
4ada57e0 150 # cheap fail-fast check for PERLDBf_SUBLINE and '&'
151 if ($^P and $^P & 0x10 && $sigil eq '&') {
640de369 152 my $filename = $opts{filename};
153 my $first_line_num = $opts{first_line_num};
4ada57e0 154
640de369 155 (undef, $filename, $first_line_num) = caller
4ada57e0 156 if not defined $filename;
640de369 157
158 my $last_line_num = $opts{last_line_num} || ($first_line_num ||= 0);
4ada57e0 159
160 # http://perldoc.perl.org/perldebguts.html#Debugger-Internals
640de369 161 $DB::sub{$pkg . '::' . $name} = "$filename:$first_line_num-$last_line_num";
4ada57e0 162 }
163 }
f10f6217 164
165 no strict 'refs';
166 no warnings 'redefine', 'misc', 'prototype';
167 *{$pkg . '::' . $name} = ref $initial_value ? $initial_value : \$initial_value;
168}
169
988beb41 170=method remove_package_glob $name
683542f5 171
172Removes all package variables with the given name, regardless of sigil.
173
174=cut
175
f10f6217 176sub remove_package_glob {
177 my ($self, $name) = @_;
178 no strict 'refs';
179 delete ${$self->name . '::'}{$name};
180}
181
182# ... these functions deal with stuff on the namespace level
183
988beb41 184=method has_package_symbol $variable
683542f5 185
186Returns whether or not the given package variable (including sigil) exists.
187
188=cut
189
f10f6217 190sub has_package_symbol {
191 my ($self, $variable) = @_;
192
193 my ($name, $sigil, $type) = ref $variable eq 'HASH'
194 ? @{$variable}{qw[name sigil type]}
195 : $self->_deconstruct_variable_name($variable);
196
197 my $namespace = $self->namespace;
198
199 return unless exists $namespace->{$name};
200
201 my $entry_ref = \$namespace->{$name};
202 if (reftype($entry_ref) eq 'GLOB') {
203 if ( $type eq 'SCALAR' ) {
204 return defined ${ *{$entry_ref}{SCALAR} };
205 }
206 else {
207 return defined *{$entry_ref}{$type};
208 }
209 }
210 else {
211 # a symbol table entry can be -1 (stub), string (stub with prototype),
212 # or reference (constant)
213 return $type eq 'CODE';
214 }
215}
216
988beb41 217=method get_package_symbol $variable
683542f5 218
219Returns the value of the given package variable (including sigil).
220
221=cut
222
f10f6217 223sub get_package_symbol {
e55803fc 224 my ($self, $variable, %opts) = @_;
f10f6217 225
226 my ($name, $sigil, $type) = ref $variable eq 'HASH'
227 ? @{$variable}{qw[name sigil type]}
228 : $self->_deconstruct_variable_name($variable);
229
230 my $namespace = $self->namespace;
231
f8e7797c 232 if ($opts{vivify} && !exists $namespace->{$name}) {
233 if ($type eq 'ARRAY') {
234 $self->add_package_symbol(
235 $variable,
236 # setting our own arrayref manually loses the magicalness or
237 # something
238 $name eq 'ISA' ? () : ([])
239 );
e55803fc 240 }
f8e7797c 241 elsif ($type eq 'HASH') {
e55803fc 242 $self->add_package_symbol($variable, {});
243 }
244 else {
245 # FIXME
246 $self->add_package_symbol($variable)
247 }
30d1a098 248 }
f10f6217 249
250 my $entry_ref = \$namespace->{$name};
251
252 if (ref($entry_ref) eq 'GLOB') {
253 return *{$entry_ref}{$type};
254 }
255 else {
256 if ($type eq 'CODE') {
257 no strict 'refs';
258 return \&{ $self->name . '::' . $name };
259 }
260 else {
261 return undef;
262 }
263 }
264}
265
988beb41 266=method get_or_add_package_symbol $variable
e55803fc 267
268Like C<get_package_symbol>, except that it will return an empty hashref or
269arrayref if the variable doesn't exist.
270
271=cut
272
273sub get_or_add_package_symbol {
274 my $self = shift;
275 $self->get_package_symbol(@_, vivify => 1);
276}
277
988beb41 278=method remove_package_symbol $variable
683542f5 279
280Removes the package variable described by C<$variable> (which includes the
281sigil); other variables with the same name but different sigils will be
282untouched.
283
284=cut
285
f10f6217 286sub remove_package_symbol {
287 my ($self, $variable) = @_;
288
289 my ($name, $sigil, $type) = ref $variable eq 'HASH'
290 ? @{$variable}{qw[name sigil type]}
291 : $self->_deconstruct_variable_name($variable);
292
293 # FIXME:
9a3d1390 294 # no doubt this is grossly inefficient and
f10f6217 295 # could be done much easier and faster in XS
296
b1a00d0e 297 my ($scalar_desc, $array_desc, $hash_desc, $code_desc, $io_desc) = (
f10f6217 298 { sigil => '$', type => 'SCALAR', name => $name },
299 { sigil => '@', type => 'ARRAY', name => $name },
300 { sigil => '%', type => 'HASH', name => $name },
301 { sigil => '&', type => 'CODE', name => $name },
b1a00d0e 302 { sigil => '', type => 'IO', name => $name },
f10f6217 303 );
304
b1a00d0e 305 my ($scalar, $array, $hash, $code, $io);
f10f6217 306 if ($type eq 'SCALAR') {
307 $array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc);
308 $hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc);
309 $code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc);
b1a00d0e 310 $io = $self->get_package_symbol($io_desc) if $self->has_package_symbol($io_desc);
f10f6217 311 }
312 elsif ($type eq 'ARRAY') {
42fa5cfc 313 $scalar = $self->get_package_symbol($scalar_desc);
f10f6217 314 $hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc);
315 $code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc);
b1a00d0e 316 $io = $self->get_package_symbol($io_desc) if $self->has_package_symbol($io_desc);
f10f6217 317 }
318 elsif ($type eq 'HASH') {
42fa5cfc 319 $scalar = $self->get_package_symbol($scalar_desc);
f10f6217 320 $array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc);
321 $code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc);
b1a00d0e 322 $io = $self->get_package_symbol($io_desc) if $self->has_package_symbol($io_desc);
f10f6217 323 }
324 elsif ($type eq 'CODE') {
42fa5cfc 325 $scalar = $self->get_package_symbol($scalar_desc);
f10f6217 326 $array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc);
327 $hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc);
b1a00d0e 328 $io = $self->get_package_symbol($io_desc) if $self->has_package_symbol($io_desc);
329 }
330 elsif ($type eq 'IO') {
42fa5cfc 331 $scalar = $self->get_package_symbol($scalar_desc);
b1a00d0e 332 $array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc);
333 $hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc);
334 $code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc);
f10f6217 335 }
336 else {
337 confess "This should never ever ever happen";
338 }
339
340 $self->remove_package_glob($name);
341
42fa5cfc 342 $self->add_package_symbol($scalar_desc => $scalar);
f10f6217 343 $self->add_package_symbol($array_desc => $array) if defined $array;
344 $self->add_package_symbol($hash_desc => $hash) if defined $hash;
345 $self->add_package_symbol($code_desc => $code) if defined $code;
b1a00d0e 346 $self->add_package_symbol($io_desc => $io) if defined $io;
f10f6217 347}
348
988beb41 349=method list_all_package_symbols $type_filter
683542f5 350
351Returns a list of package variable names in the package, without sigils. If a
352C<type_filter> is passed, it is used to select package variables of a given
353type, where valid types are the slots of a typeglob ('SCALAR', 'CODE', 'HASH',
354etc).
355
356=cut
357
f10f6217 358sub list_all_package_symbols {
359 my ($self, $type_filter) = @_;
360
361 my $namespace = $self->namespace;
362 return keys %{$namespace} unless defined $type_filter;
363
364 # NOTE:
9a3d1390 365 # or we can filter based on
f10f6217 366 # type (SCALAR|ARRAY|HASH|CODE)
367 if ($type_filter eq 'CODE') {
368 return grep {
369 (ref($namespace->{$_})
370 ? (ref($namespace->{$_}) eq 'SCALAR')
371 : (ref(\$namespace->{$_}) eq 'GLOB'
372 && defined(*{$namespace->{$_}}{CODE})));
373 } keys %{$namespace};
374 } else {
375 return grep { *{$namespace->{$_}}{$type_filter} } keys %{$namespace};
376 }
377}
f4979588 378
0992f4ec 379=head1 BUGS
380
381No known bugs.
382
383Please report any bugs through RT: email
384C<bug-package-stash at rt.cpan.org>, or browse to
385L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Package-Stash>.
386
f4979588 387=head1 SEE ALSO
388
f4979588 389=over 4
390
988beb41 391=item * L<Class::MOP::Package>
f4979588 392
988beb41 393This module is a factoring out of code that used to live here
f4979588 394
395=back
396
0992f4ec 397=head1 SUPPORT
398
399You can find this documentation for this module with the perldoc command.
400
401 perldoc Package::Stash
402
403You can also look for information at:
404
405=over 4
406
407=item * AnnoCPAN: Annotated CPAN documentation
408
409L<http://annocpan.org/dist/Package-Stash>
410
411=item * CPAN Ratings
412
413L<http://cpanratings.perl.org/d/Package-Stash>
414
415=item * RT: CPAN's request tracker
416
417L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Package-Stash>
418
419=item * Search CPAN
420
421L<http://search.cpan.org/dist/Package-Stash>
422
423=back
424
425=head1 AUTHOR
426
427Jesse Luehrs <doy at tozt dot net>
428
429Mostly copied from code from L<Class::MOP::Package>, by Stevan Little and the
430Moose Cabal.
431
f4979588 432=cut
433
4341;