| Current File : //proc/thread-self/root/usr/share/perl5/Package/Stash/PP.pm |
package Package::Stash::PP;
use strict;
use warnings;
# ABSTRACT: Pure perl implementation of the Package::Stash API
our $VERSION = '0.40';
use B;
use Carp qw(confess);
use Scalar::Util qw(blessed reftype weaken);
use Symbol;
# before 5.12, assigning to the ISA glob would make it lose its magical ->isa
# powers
use constant BROKEN_ISA_ASSIGNMENT => ($] < 5.012);
# before 5.10, stashes don't ever seem to drop to a refcount of zero, so
# weakening them isn't helpful
use constant BROKEN_WEAK_STASH => ($] < 5.010);
# before 5.10, the scalar slot was always treated as existing if the
# glob existed
use constant BROKEN_SCALAR_INITIALIZATION => ($] < 5.010);
# add_method on anon stashes triggers rt.perl #1804 otherwise
# fixed in perl commit v5.13.3-70-g0fe688f
use constant BROKEN_GLOB_ASSIGNMENT => ($] < 5.013004);
# pre-5.10, ->isa lookups were cached in the ::ISA::CACHE:: slot
use constant HAS_ISA_CACHE => ($] < 5.010);
#pod =head1 SYNOPSIS
#pod
#pod use Package::Stash;
#pod
#pod =head1 DESCRIPTION
#pod
#pod This is a backend for L<Package::Stash> implemented in pure perl, for those without a compiler or who would like to use this inline in scripts.
#pod
#pod =cut
sub new {
my $class = shift;
my ($package) = @_;
if (!defined($package) || (ref($package) && reftype($package) ne 'HASH')) {
confess "Package::Stash->new must be passed the name of the "
. "package to access";
}
elsif (ref($package) && reftype($package) eq 'HASH') {
confess "The PP implementation of Package::Stash does not support "
. "anonymous stashes before perl 5.14"
if BROKEN_GLOB_ASSIGNMENT;
return bless {
'namespace' => $package,
}, $class;
}
elsif ($package =~ /\A[0-9A-Z_a-z]+(?:::[0-9A-Z_a-z]+)*\z/) {
return bless {
'package' => $package,
}, $class;
}
else {
confess "$package is not a module name";
}
}
sub name {
confess "Can't call name as a class method"
unless blessed($_[0]);
confess "Can't get the name of an anonymous package"
unless defined($_[0]->{package});
return $_[0]->{package};
}
sub namespace {
confess "Can't call namespace as a class method"
unless blessed($_[0]);
if (BROKEN_WEAK_STASH) {
no strict 'refs';
return \%{$_[0]->name . '::'};
}
else {
return $_[0]->{namespace} if defined $_[0]->{namespace};
{
no strict 'refs';
$_[0]->{namespace} = \%{$_[0]->name . '::'};
}
weaken($_[0]->{namespace});
return $_[0]->{namespace};
}
}
{
my %SIGIL_MAP = (
'$' => 'SCALAR',
'@' => 'ARRAY',
'%' => 'HASH',
'&' => 'CODE',
'' => 'IO',
);
sub _deconstruct_variable_name {
my ($variable) = @_;
my @ret;
if (ref($variable) eq 'HASH') {
@ret = @{$variable}{qw[name sigil type]};
}
else {
(defined $variable && length $variable)
|| confess "You must pass a variable name";
my $sigil = substr($variable, 0, 1, '');
if (exists $SIGIL_MAP{$sigil}) {
@ret = ($variable, $sigil, $SIGIL_MAP{$sigil});
}
else {
@ret = ("${sigil}${variable}", '', $SIGIL_MAP{''});
}
}
# XXX in pure perl, this will access things in inner packages,
# in xs, this will segfault - probably look more into this at
# some point
($ret[0] !~ /::/)
|| confess "Variable names may not contain ::";
return @ret;
}
}
sub _valid_for_type {
my ($value, $type) = @_;
if ($type eq 'HASH' || $type eq 'ARRAY'
|| $type eq 'IO' || $type eq 'CODE') {
return reftype($value) eq $type;
}
else {
my $ref = reftype($value);
return !defined($ref) || $ref eq 'SCALAR' || $ref eq 'REF' || $ref eq 'LVALUE' || $ref eq 'REGEXP' || $ref eq 'VSTRING';
}
}
sub add_symbol {
my ($self, $variable, $initial_value, %opts) = @_;
my ($name, $sigil, $type) = _deconstruct_variable_name($variable);
if (@_ > 2) {
_valid_for_type($initial_value, $type)
|| confess "$initial_value is not of type $type";
# cheap fail-fast check for PERLDBf_SUBLINE and '&'
if ($^P and $^P & 0x10 && $sigil eq '&') {
my $filename = $opts{filename};
my $first_line_num = $opts{first_line_num};
(undef, $filename, $first_line_num) = caller
if not defined $filename;
my $last_line_num = $opts{last_line_num} || ($first_line_num ||= 0);
# http://perldoc.perl.org/perldebguts.html#Debugger-Internals
$DB::sub{$self->name . '::' . $name} = "$filename:$first_line_num-$last_line_num";
}
}
if (BROKEN_GLOB_ASSIGNMENT) {
if (@_ > 2) {
no strict 'refs';
no warnings 'redefine';
*{ $self->name . '::' . $name } = ref $initial_value
? $initial_value : \$initial_value;
}
else {
no strict 'refs';
if (BROKEN_ISA_ASSIGNMENT && $name eq 'ISA') {
*{ $self->name . '::' . $name };
}
else {
my $undef = _undef_ref_for_type($type);
*{ $self->name . '::' . $name } = $undef;
}
}
}
else {
my $namespace = $self->namespace;
{
# using glob aliasing instead of Symbol::gensym, because otherwise,
# magic doesn't get applied properly.
# see <20120710063744.19360.qmail@lists-nntp.develooper.com> on p5p
local *__ANON__:: = $namespace;
no strict 'refs';
no warnings 'void';
no warnings 'once';
*{"__ANON__::$name"};
}
if (@_ > 2) {
no warnings 'redefine';
*{ $namespace->{$name} } = ref $initial_value
? $initial_value : \$initial_value;
}
else {
return if BROKEN_ISA_ASSIGNMENT && $name eq 'ISA';
*{ $namespace->{$name} } = _undef_ref_for_type($type);
}
}
}
sub _undef_ref_for_type {
my ($type) = @_;
if ($type eq 'ARRAY') {
return [];
}
elsif ($type eq 'HASH') {
return {};
}
elsif ($type eq 'SCALAR') {
return \undef;
}
elsif ($type eq 'IO') {
return Symbol::geniosym;
}
elsif ($type eq 'CODE') {
confess "Don't know how to vivify CODE variables";
}
else {
confess "Unknown type $type in vivication";
}
}
sub remove_glob {
my ($self, $name) = @_;
delete $self->namespace->{$name};
}
sub has_symbol {
my ($self, $variable) = @_;
my ($name, $sigil, $type) = _deconstruct_variable_name($variable);
my $namespace = $self->namespace;
return unless exists $namespace->{$name};
my $entry_ref = \$namespace->{$name};
if (reftype($entry_ref) eq 'GLOB') {
if ($type eq 'SCALAR') {
if (BROKEN_SCALAR_INITIALIZATION) {
return defined ${ *{$entry_ref}{$type} };
}
else {
my $sv = B::svref_2object($entry_ref)->SV;
return $sv->isa('B::SV')
|| ($sv->isa('B::SPECIAL')
&& $B::specialsv_name[$$sv] ne 'Nullsv');
}
}
else {
return defined *{$entry_ref}{$type};
}
}
else {
# a symbol table entry can be -1 (stub), string (stub with prototype),
# or reference (constant)
return $type eq 'CODE';
}
}
sub get_symbol {
my ($self, $variable, %opts) = @_;
my ($name, $sigil, $type) = _deconstruct_variable_name($variable);
my $namespace = $self->namespace;
if (!exists $namespace->{$name}) {
if ($opts{vivify}) {
$self->add_symbol($variable);
}
else {
return undef;
}
}
my $entry_ref = \$namespace->{$name};
if (ref($entry_ref) eq 'GLOB') {
return *{$entry_ref}{$type};
}
else {
if ($type eq 'CODE') {
if (BROKEN_GLOB_ASSIGNMENT || defined($self->{package})) {
no strict 'refs';
return \&{ $self->name . '::' . $name };
}
# XXX we should really be able to support arbitrary anonymous
# stashes here... (not just via Package::Anon)
if (blessed($namespace) && $namespace->isa('Package::Anon')) {
# ->can will call gv_init for us, which inflates the glob
# don't know how to do this in general
$namespace->bless(\(my $foo))->can($name);
}
else {
confess "Don't know how to inflate a " . ref($entry_ref)
. " into a full coderef (perhaps you could use"
. " Package::Anon instead of a bare stash?)"
}
return *{ $namespace->{$name} }{CODE};
}
else {
return undef;
}
}
}
sub get_or_add_symbol {
my $self = shift;
$self->get_symbol(@_, vivify => 1);
}
sub remove_symbol {
my ($self, $variable) = @_;
my ($name, $sigil, $type) = _deconstruct_variable_name($variable);
# FIXME:
# no doubt this is grossly inefficient and
# could be done much easier and faster in XS
my %desc = (
SCALAR => { sigil => '$', type => 'SCALAR', name => $name },
ARRAY => { sigil => '@', type => 'ARRAY', name => $name },
HASH => { sigil => '%', type => 'HASH', name => $name },
CODE => { sigil => '&', type => 'CODE', name => $name },
IO => { sigil => '', type => 'IO', name => $name },
);
confess "This should never ever ever happen" if !$desc{$type};
my @types_to_store = grep { $type ne $_ && $self->has_symbol($desc{$_}) }
keys %desc;
my %values = map { $_, $self->get_symbol($desc{$_}) } @types_to_store;
$values{SCALAR} = $self->get_symbol($desc{SCALAR})
if !defined $values{SCALAR}
&& $type ne 'SCALAR'
&& BROKEN_SCALAR_INITIALIZATION;
$self->remove_glob($name);
$self->add_symbol($desc{$_} => $values{$_})
for grep { defined $values{$_} } keys %values;
}
sub list_all_symbols {
my ($self, $type_filter) = @_;
my $namespace = $self->namespace;
if (HAS_ISA_CACHE) {
return grep { $_ ne '::ISA::CACHE::' } keys %{$namespace}
unless defined $type_filter;
}
else {
return keys %{$namespace}
unless defined $type_filter;
}
# NOTE:
# or we can filter based on
# type (SCALAR|ARRAY|HASH|CODE)
if ($type_filter eq 'CODE') {
return grep {
# any non-typeglob in the symbol table is a constant or stub
ref(\$namespace->{$_}) ne 'GLOB'
# regular subs are stored in the CODE slot of the typeglob
|| defined(*{$namespace->{$_}}{CODE})
} keys %{$namespace};
}
elsif ($type_filter eq 'SCALAR') {
return grep {
!(HAS_ISA_CACHE && $_ eq '::ISA::CACHE::') &&
(BROKEN_SCALAR_INITIALIZATION
? (ref(\$namespace->{$_}) eq 'GLOB'
&& defined(${*{$namespace->{$_}}{'SCALAR'}}))
: (do {
my $entry = \$namespace->{$_};
ref($entry) eq 'GLOB'
&& B::svref_2object($entry)->SV->isa('B::SV')
}))
} keys %{$namespace};
}
else {
return grep {
ref(\$namespace->{$_}) eq 'GLOB'
&& defined(*{$namespace->{$_}}{$type_filter})
} keys %{$namespace};
}
}
sub get_all_symbols {
my ($self, $type_filter) = @_;
my $namespace = $self->namespace;
return { %{$namespace} } unless defined $type_filter;
return {
map { $_ => $self->get_symbol({name => $_, type => $type_filter}) }
$self->list_all_symbols($type_filter)
}
}
__END__
=pod
=encoding UTF-8
=head1 NAME
Package::Stash::PP - Pure perl implementation of the Package::Stash API
=head1 VERSION
version 0.40
=head1 SYNOPSIS
use Package::Stash;
=head1 DESCRIPTION
This is a backend for L<Package::Stash> implemented in pure perl, for those without a compiler or who would like to use this inline in scripts.
=head1 BUGS
=for stopwords TODO
=over 4
=item * remove_symbol also replaces the associated typeglob
This can cause unexpected behavior when doing manipulation at compile time -
removing subroutines will still allow them to be called from within the package
as subroutines (although they will not be available as methods). This can be
considered a feature in some cases (this is how L<namespace::clean> works, for
instance), but should not be relied upon - use C<remove_glob> directly if you
want this behavior.
=item * Some minor memory leaks
The pure perl implementation has a couple minor memory leaks (see the TODO
tests in t/20-leaks.t) that I'm having a hard time tracking down - these may be
core perl bugs, it's hard to tell.
=back
=head1 SEE ALSO
=over 4
=item * L<Class::MOP::Package>
This module is a factoring out of code that used to live here
=back
=for Pod::Coverage BROKEN_ISA_ASSIGNMENT
add_symbol
get_all_symbols
get_or_add_symbol
get_symbol
has_symbol
list_all_symbols
name
namespace
new
remove_glob
=head1 SUPPORT
Bugs may be submitted through L<the RT bug tracker|https://rt.cpan.org/Public/Dist/Display.html?Name=Package-Stash>
(or L<bug-Package-Stash@rt.cpan.org|mailto:bug-Package-Stash@rt.cpan.org>).
=head1 AUTHOR
Mostly copied from code from L<Class::MOP::Package>, by Stevan Little and the
Moose Cabal.
=head1 COPYRIGHT AND LICENSE
This software is copyright (c) 2022 by Jesse Luehrs.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.
=cut