[gitmo/Package-Stash.git] / lib / Stash / Manip.pm

package Stash::Manip;
use strict;
use warnings;

use Carp qw(confess);
use Scalar::Util qw(reftype);

=head1 NAME

Stash::Manip - routines for manipulating stashes

=head1 SYNOPSIS

  my $stash = Stash::Manip->new('Foo');
  $stash->add_package_symbol('%foo', {bar => 1});
  # $Foo::foo{bar} == 1
  $stash->has_package_symbol('$foo') # false
  my $namespace = $stash->namespace;
  *{ $namespace->{foo} }{HASH} # {bar => 1}

=head1 DESCRIPTION

Manipulating stashes (Perl's symbol tables) is occasionally necessary, but
incredibly messy, and easy to get wrong. This module hides all of that behind a
simple API.

=head1 METHODS

=cut

=head2 new $package_name

Creates a new C<Stash::Manip> object, for the package given as the only
argument.

=cut

sub new {
    my $class = shift;
    my ($namespace) = @_;
    return bless { package => $namespace }, $class;
}

=head2 name

Returns the name of the package that this object represents.

=cut

sub name {
    return $_[0]->{package};
}

=head2 namespace

Returns the raw stash itself.

=cut

sub namespace {
    # NOTE:
    # because of issues with the Perl API 
    # to the typeglob in some versions, we 
    # need to just always grab a new 
    # reference to the hash here. Ideally 
    # we could just store a ref and it would
    # Just Work, but oh well :\    
    no strict 'refs';
    return \%{$_[0]->name . '::'};
}

{
    my %SIGIL_MAP = (
        '$' => 'SCALAR',
        '@' => 'ARRAY',
        '%' => 'HASH',
        '&' => 'CODE',
    );

    sub _deconstruct_variable_name {
        my ($self, $variable) = @_;

        (defined $variable)
            || confess "You must pass a variable name";

        my $sigil = substr($variable, 0, 1, '');

        (defined $sigil)
            || confess "The variable name must include a sigil";

        (exists $SIGIL_MAP{$sigil})
            || confess "I do not recognize that sigil '$sigil'";

        return ($variable, $sigil, $SIGIL_MAP{$sigil});
    }
}

=head2 add_package_symbol $variable $value

Adds a new package symbol, for the symbol given as C<$variable>, and optionally
gives it an initial value of C<$value>. C<$variable> should be the name of
variable including the sigil, so

  Stash::Manip->new('Foo')->add_package_symbol('%foo')

will create C<%Foo::foo>.

=cut

sub add_package_symbol {
    my ($self, $variable, $initial_value) = @_;

    my ($name, $sigil, $type) = ref $variable eq 'HASH'
        ? @{$variable}{qw[name sigil type]}
        : $self->_deconstruct_variable_name($variable);

    my $pkg = $self->name;

    no strict 'refs';
    no warnings 'redefine', 'misc', 'prototype';
    *{$pkg . '::' . $name} = ref $initial_value ? $initial_value : \$initial_value;
}

=head2 remove_package_glob $name

Removes all package variables with the given name, regardless of sigil.

=cut

sub remove_package_glob {
    my ($self, $name) = @_;
    no strict 'refs';
    delete ${$self->name . '::'}{$name};
}

# ... these functions deal with stuff on the namespace level

=head2 has_package_symbol $variable

Returns whether or not the given package variable (including sigil) exists.

=cut

sub has_package_symbol {
    my ($self, $variable) = @_;

    my ($name, $sigil, $type) = ref $variable eq 'HASH'
        ? @{$variable}{qw[name sigil type]}
        : $self->_deconstruct_variable_name($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' ) {
            return defined ${ *{$entry_ref}{SCALAR} };
        }
        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';
    }
}

=head2 get_package_symbol $variable

Returns the value of the given package variable (including sigil).

=cut

sub get_package_symbol {
    my ($self, $variable) = @_;

    my ($name, $sigil, $type) = ref $variable eq 'HASH'
        ? @{$variable}{qw[name sigil type]}
        : $self->_deconstruct_variable_name($variable);

    my $namespace = $self->namespace;

    # FIXME
    $self->add_package_symbol($variable)
        unless exists $namespace->{$name};

    my $entry_ref = \$namespace->{$name};

    if (ref($entry_ref) eq 'GLOB') {
        return *{$entry_ref}{$type};
    }
    else {
        if ($type eq 'CODE') {
            no strict 'refs';
            return \&{ $self->name . '::' . $name };
        }
        else {
            return undef;
        }
    }
}

=head2 remove_package_symbol $variable

Removes the package variable described by C<$variable> (which includes the
sigil); other variables with the same name but different sigils will be
untouched.

=cut

sub remove_package_symbol {
    my ($self, $variable) = @_;

    my ($name, $sigil, $type) = ref $variable eq 'HASH'
        ? @{$variable}{qw[name sigil type]}
        : $self->_deconstruct_variable_name($variable);

    # FIXME:
    # no doubt this is grossly inefficient and 
    # could be done much easier and faster in XS

    my ($scalar_desc, $array_desc, $hash_desc, $code_desc) = (
        { sigil => '$', type => 'SCALAR', name => $name },
        { sigil => '@', type => 'ARRAY',  name => $name },
        { sigil => '%', type => 'HASH',   name => $name },
        { sigil => '&', type => 'CODE',   name => $name },
    );

    my ($scalar, $array, $hash, $code);
    if ($type eq 'SCALAR') {
        $array  = $self->get_package_symbol($array_desc)  if $self->has_package_symbol($array_desc);
        $hash   = $self->get_package_symbol($hash_desc)   if $self->has_package_symbol($hash_desc);
        $code   = $self->get_package_symbol($code_desc)   if $self->has_package_symbol($code_desc);
    }
    elsif ($type eq 'ARRAY') {
        $scalar = $self->get_package_symbol($scalar_desc) if $self->has_package_symbol($scalar_desc);
        $hash   = $self->get_package_symbol($hash_desc)   if $self->has_package_symbol($hash_desc);
        $code   = $self->get_package_symbol($code_desc)   if $self->has_package_symbol($code_desc);
    }
    elsif ($type eq 'HASH') {
        $scalar = $self->get_package_symbol($scalar_desc) if $self->has_package_symbol($scalar_desc);
        $array  = $self->get_package_symbol($array_desc)  if $self->has_package_symbol($array_desc);
        $code   = $self->get_package_symbol($code_desc)   if $self->has_package_symbol($code_desc);
    }
    elsif ($type eq 'CODE') {
        $scalar = $self->get_package_symbol($scalar_desc) if $self->has_package_symbol($scalar_desc);
        $array  = $self->get_package_symbol($array_desc)  if $self->has_package_symbol($array_desc);
        $hash   = $self->get_package_symbol($hash_desc)   if $self->has_package_symbol($hash_desc);
    }
    else {
        confess "This should never ever ever happen";
    }

    $self->remove_package_glob($name);

    $self->add_package_symbol($scalar_desc => $scalar) if defined $scalar;
    $self->add_package_symbol($array_desc  => $array)  if defined $array;
    $self->add_package_symbol($hash_desc   => $hash)   if defined $hash;
    $self->add_package_symbol($code_desc   => $code)   if defined $code;
}

=head2 list_all_package_symbols $type_filter

Returns a list of package variable names in the package, without sigils. If a
C<type_filter> is passed, it is used to select package variables of a given
type, where valid types are the slots of a typeglob ('SCALAR', 'CODE', 'HASH',
etc).

=cut

sub list_all_package_symbols {
    my ($self, $type_filter) = @_;

    my $namespace = $self->namespace;
    return keys %{$namespace} unless defined $type_filter;

    # NOTE:
    # or we can filter based on 
    # type (SCALAR|ARRAY|HASH|CODE)
    if ($type_filter eq 'CODE') {
        return grep {
            (ref($namespace->{$_})
                ? (ref($namespace->{$_}) eq 'SCALAR')
                : (ref(\$namespace->{$_}) eq 'GLOB'
                   && defined(*{$namespace->{$_}}{CODE})));
        } keys %{$namespace};
    } else {
        return grep { *{$namespace->{$_}}{$type_filter} } keys %{$namespace};
    }
}

=head1 BUGS

No known bugs.

Please report any bugs through RT: email
C<bug-stash-manip at rt.cpan.org>, or browse to
L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Stash-Manip>.

=head1 SEE ALSO

L<Class::MOP::Package> - this module is a factoring out of code that used to
live here

=head1 SUPPORT

You can find this documentation for this module with the perldoc command.

    perldoc Stash::Manip

You can also look for information at:

=over 4

=item * AnnoCPAN: Annotated CPAN documentation

L<http://annocpan.org/dist/Stash-Manip>

=item * CPAN Ratings

L<http://cpanratings.perl.org/d/Stash-Manip>

=item * RT: CPAN's request tracker

L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Stash-Manip>

=item * Search CPAN

L<http://search.cpan.org/dist/Stash-Manip>

=back

=head1 AUTHOR

  Jesse Luehrs <doy at tozt dot net>

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) 2010 by Jesse Luehrs.

This is free software; you can redistribute it and/or modify it under
the same terms as perl itself.

=cut

1;
Commit	Line	Data
f4979588	1	package Stash::Manip;
f10f6217	2	use strict;
	3	use warnings;
	4
	5	use Carp qw(confess);
	6	use Scalar::Util qw(reftype);
f4979588	7
	8	=head1 NAME
	9
683542f5	10	Stash::Manip - routines for manipulating stashes
f4979588	11
	12	=head1 SYNOPSIS
	13
683542f5	14	my $stash = Stash::Manip->new('Foo');
	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	23	Manipulating stashes (Perl's symbol tables) is occasionally necessary, but
	24	incredibly messy, and easy to get wrong. This module hides all of that behind a
	25	simple API.
	26
	27	=head1 METHODS
	28
	29	=cut
	30
	31	=head2 new $package_name
	32
	33	Creates a new C<Stash::Manip> object, for the package given as the only
	34	argument.
f4979588	35
	36	=cut
	37
f10f6217	38	sub new {
	39	my $class = shift;
	40	my ($namespace) = @_;
	41	return bless { package => $namespace }, $class;
	42	}
	43
683542f5	44	=head2 name
	45
	46	Returns the name of the package that this object represents.
	47
	48	=cut
	49
f10f6217	50	sub name {
	51	return $_[0]->{package};
	52	}
	53
683542f5	54	=head2 namespace
	55
	56	Returns the raw stash itself.
	57
	58	=cut
	59
f10f6217	60	sub namespace {
	61	# NOTE:
	62	# because of issues with the Perl API
	63	# to the typeglob in some versions, we
	64	# need to just always grab a new
	65	# reference to the hash here. Ideally
	66	# we could just store a ref and it would
	67	# Just Work, but oh well :\
	68	no strict 'refs';
	69	return \%{$_[0]->name . '::'};
	70	}
	71
	72	{
	73	my %SIGIL_MAP = (
	74	'$' => 'SCALAR',
	75	'@' => 'ARRAY',
	76	'%' => 'HASH',
	77	'&' => 'CODE',
	78	);
	79
	80	sub _deconstruct_variable_name {
	81	my ($self, $variable) = @_;
	82
	83	(defined $variable)
	84	\|\| confess "You must pass a variable name";
	85
	86	my $sigil = substr($variable, 0, 1, '');
	87
	88	(defined $sigil)
	89	\|\| confess "The variable name must include a sigil";
	90
	91	(exists $SIGIL_MAP{$sigil})
	92	\|\| confess "I do not recognize that sigil '$sigil'";
	93
	94	return ($variable, $sigil, $SIGIL_MAP{$sigil});
	95	}
	96	}
	97
683542f5	98	=head2 add_package_symbol $variable $value
	99
	100	Adds a new package symbol, for the symbol given as C<$variable>, and optionally
	101	gives it an initial value of C<$value>. C<$variable> should be the name of
	102	variable including the sigil, so
	103
	104	Stash::Manip->new('Foo')->add_package_symbol('%foo')
	105
	106	will create C<%Foo::foo>.
	107
	108	=cut
	109
f10f6217	110	sub add_package_symbol {
	111	my ($self, $variable, $initial_value) = @_;
	112
	113	my ($name, $sigil, $type) = ref $variable eq 'HASH'
	114	? @{$variable}{qw[name sigil type]}
	115	: $self->_deconstruct_variable_name($variable);
	116
	117	my $pkg = $self->name;
	118
	119	no strict 'refs';
	120	no warnings 'redefine', 'misc', 'prototype';
	121	*{$pkg . '::' . $name} = ref $initial_value ? $initial_value : \$initial_value;
	122	}
	123
683542f5	124	=head2 remove_package_glob $name
	125
	126	Removes all package variables with the given name, regardless of sigil.
	127
	128	=cut
	129
f10f6217	130	sub remove_package_glob {
	131	my ($self, $name) = @_;
	132	no strict 'refs';
	133	delete ${$self->name . '::'}{$name};
	134	}
	135
	136	# ... these functions deal with stuff on the namespace level
	137
683542f5	138	=head2 has_package_symbol $variable
	139
	140	Returns whether or not the given package variable (including sigil) exists.
	141
	142	=cut
	143
f10f6217	144	sub has_package_symbol {
	145	my ($self, $variable) = @_;
	146
	147	my ($name, $sigil, $type) = ref $variable eq 'HASH'
	148	? @{$variable}{qw[name sigil type]}
	149	: $self->_deconstruct_variable_name($variable);
	150
	151	my $namespace = $self->namespace;
	152
	153	return unless exists $namespace->{$name};
	154
	155	my $entry_ref = \$namespace->{$name};
	156	if (reftype($entry_ref) eq 'GLOB') {
	157	if ( $type eq 'SCALAR' ) {
	158	return defined ${ *{$entry_ref}{SCALAR} };
	159	}
	160	else {
	161	return defined *{$entry_ref}{$type};
	162	}
	163	}
	164	else {
	165	# a symbol table entry can be -1 (stub), string (stub with prototype),
	166	# or reference (constant)
	167	return $type eq 'CODE';
	168	}
	169	}
	170
683542f5	171	=head2 get_package_symbol $variable
	172
	173	Returns the value of the given package variable (including sigil).
	174
	175	=cut
	176
f10f6217	177	sub get_package_symbol {
	178	my ($self, $variable) = @_;
	179
	180	my ($name, $sigil, $type) = ref $variable eq 'HASH'
	181	? @{$variable}{qw[name sigil type]}
	182	: $self->_deconstruct_variable_name($variable);
	183
	184	my $namespace = $self->namespace;
	185
	186	# FIXME
	187	$self->add_package_symbol($variable)
	188	unless exists $namespace->{$name};
	189
	190	my $entry_ref = \$namespace->{$name};
	191
	192	if (ref($entry_ref) eq 'GLOB') {
	193	return *{$entry_ref}{$type};
	194	}
	195	else {
	196	if ($type eq 'CODE') {
	197	no strict 'refs';
	198	return \&{ $self->name . '::' . $name };
	199	}
	200	else {
	201	return undef;
	202	}
	203	}
	204	}
	205
683542f5	206	=head2 remove_package_symbol $variable
	207
	208	Removes the package variable described by C<$variable> (which includes the
	209	sigil); other variables with the same name but different sigils will be
	210	untouched.
	211
	212	=cut
	213
f10f6217	214	sub remove_package_symbol {
	215	my ($self, $variable) = @_;
	216
	217	my ($name, $sigil, $type) = ref $variable eq 'HASH'
	218	? @{$variable}{qw[name sigil type]}
	219	: $self->_deconstruct_variable_name($variable);
	220
	221	# FIXME:
	222	# no doubt this is grossly inefficient and
	223	# could be done much easier and faster in XS
	224
	225	my ($scalar_desc, $array_desc, $hash_desc, $code_desc) = (
	226	{ sigil => '$', type => 'SCALAR', name => $name },
	227	{ sigil => '@', type => 'ARRAY', name => $name },
	228	{ sigil => '%', type => 'HASH', name => $name },
	229	{ sigil => '&', type => 'CODE', name => $name },
	230	);
	231
	232	my ($scalar, $array, $hash, $code);
	233	if ($type eq 'SCALAR') {
	234	$array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc);
	235	$hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc);
	236	$code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc);
	237	}
	238	elsif ($type eq 'ARRAY') {
	239	$scalar = $self->get_package_symbol($scalar_desc) if $self->has_package_symbol($scalar_desc);
	240	$hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc);
	241	$code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc);
	242	}
	243	elsif ($type eq 'HASH') {
	244	$scalar = $self->get_package_symbol($scalar_desc) if $self->has_package_symbol($scalar_desc);
	245	$array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc);
	246	$code = $self->get_package_symbol($code_desc) if $self->has_package_symbol($code_desc);
	247	}
	248	elsif ($type eq 'CODE') {
	249	$scalar = $self->get_package_symbol($scalar_desc) if $self->has_package_symbol($scalar_desc);
	250	$array = $self->get_package_symbol($array_desc) if $self->has_package_symbol($array_desc);
	251	$hash = $self->get_package_symbol($hash_desc) if $self->has_package_symbol($hash_desc);
	252	}
	253	else {
	254	confess "This should never ever ever happen";
	255	}
	256
	257	$self->remove_package_glob($name);
	258
	259	$self->add_package_symbol($scalar_desc => $scalar) if defined $scalar;
	260	$self->add_package_symbol($array_desc => $array) if defined $array;
	261	$self->add_package_symbol($hash_desc => $hash) if defined $hash;
	262	$self->add_package_symbol($code_desc => $code) if defined $code;
	263	}
	264
683542f5	265	=head2 list_all_package_symbols $type_filter
	266
	267	Returns a list of package variable names in the package, without sigils. If a
	268	C<type_filter> is passed, it is used to select package variables of a given
	269	type, where valid types are the slots of a typeglob ('SCALAR', 'CODE', 'HASH',
	270	etc).
	271
	272	=cut
	273
f10f6217	274	sub list_all_package_symbols {
	275	my ($self, $type_filter) = @_;
	276
	277	my $namespace = $self->namespace;
	278	return keys %{$namespace} unless defined $type_filter;
	279
	280	# NOTE:
	281	# or we can filter based on
	282	# type (SCALAR\|ARRAY\|HASH\|CODE)
	283	if ($type_filter eq 'CODE') {
	284	return grep {
	285	(ref($namespace->{$_})
	286	? (ref($namespace->{$_}) eq 'SCALAR')
	287	: (ref(\$namespace->{$_}) eq 'GLOB'
	288	&& defined(*{$namespace->{$_}}{CODE})));
	289	} keys %{$namespace};
	290	} else {
	291	return grep { *{$namespace->{$_}}{$type_filter} } keys %{$namespace};
	292	}
	293	}
f4979588	294
	295	=head1 BUGS
	296
	297	No known bugs.
	298
	299	Please report any bugs through RT: email
	300	C<bug-stash-manip at rt.cpan.org>, or browse to
	301	L<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Stash-Manip>.
	302
	303	=head1 SEE ALSO
	304
683542f5	305	L<Class::MOP::Package> - this module is a factoring out of code that used to
683542f5	306	live here
f4979588	307
	308	=head1 SUPPORT
	309
	310	You can find this documentation for this module with the perldoc command.
	311
	312	perldoc Stash::Manip
	313
	314	You can also look for information at:
	315
	316	=over 4
	317
	318	=item * AnnoCPAN: Annotated CPAN documentation
	319
	320	L<http://annocpan.org/dist/Stash-Manip>
	321
	322	=item * CPAN Ratings
	323
	324	L<http://cpanratings.perl.org/d/Stash-Manip>
	325
	326	=item * RT: CPAN's request tracker
	327
	328	L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Stash-Manip>
	329
	330	=item * Search CPAN
	331
	332	L<http://search.cpan.org/dist/Stash-Manip>
	333
	334	=back
	335
	336	=head1 AUTHOR
	337
	338	Jesse Luehrs <doy at tozt dot net>
	339
683542f5	340	Mostly copied from code from L<Class::MOP::Package>, by Stevan Little and the
	341	Moose Cabal.
	342
f4979588	343	=head1 COPYRIGHT AND LICENSE
	344
	345	This software is copyright (c) 2010 by Jesse Luehrs.
	346
	347	This is free software; you can redistribute it and/or modify it under
	348	the same terms as perl itself.
	349
	350	=cut
	351
	352	1;