X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=blobdiff_plain;f=lib%2FMooseX%2FStorage.pm;h=b5731d4f8a48de84b3384d4d8261d4470b3fdec6;hb=e44b5f5498b782752d2c91b6796698c86143a2f0;hp=e3e2c3ecf5155857b3808115b4cc24a20c235231;hpb=e97396242e8acc8dff6cf3f4f5961ee1fbd8498e;p=gitmo%2FMooseX-Storage.git

diff --git a/lib/MooseX/Storage.pm b/lib/MooseX/Storage.pm
index e3e2c3e..b5731d4 100644
--- a/lib/MooseX/Storage.pm
+++ b/lib/MooseX/Storage.pm
@@ -1,27 +1,107 @@
 
 package MooseX::Storage;
+use Moose qw(confess);
+
+use MooseX::Storage::Meta::Attribute::DoNotSerialize;
+use String::RewritePrefix ();
+
+our $VERSION   = '0.32';
+our $AUTHORITY = 'cpan:STEVAN';
 
 sub import {
     my $pkg = caller();
-    $pkg->meta->alias_method('Storage' => sub {
-        my $engine_name = 'MooseX::Storage::' . (shift);
-        Class::MOP::load_class($engine_name) 
-            || die "Could not load engine ($engine_name) for package ($pkg)";
-        return $engine_name;
-    });
+
+    return if $pkg eq 'main';
+
+    ($pkg->can('meta'))
+        || confess "This package can only be used in Moose based classes";
+
+    $pkg->meta->add_method('Storage' => __PACKAGE__->meta->find_method_by_name('_injected_storage_role_generator'));
+}
+
+my %HORRIBLE_GC_AVOIDANCE_HACK;
+
+sub _rewrite_role_name {
+    my ($self, $base, $string) = @_;
+
+    my $role_name = scalar String::RewritePrefix->rewrite(
+        {
+            ''  => "MooseX::Storage::$base\::",
+            '=' => '',
+        },
+        $string,
+    );
+}
+
+sub _expand_role {
+    my ($self, $base, $value) = @_;
+
+    return unless defined $value;
+
+    if (ref $value) {
+        confess "too many args in arrayref role declaration" if @$value > 2;
+        my ($class, $param) = @$value;
+
+        $class = $self->_rewrite_role_name($base => $class);
+        Class::MOP::load_class($class);
+
+        my $role = $class->meta->generate_role(parameters => $param);
+
+        $HORRIBLE_GC_AVOIDANCE_HACK{ $role->name } = $role;
+        return $role->name;
+    } else {
+        my $class = $self->_rewrite_role_name($base, $value);
+        Class::MOP::load_class($class);
+
+        my $role = $class;
+
+        if ($class->meta->isa(
+            'MooseX::Role::Parameterized::Meta::Role::Parameterizable'
+        )) {
+            $role = $class->meta->generate_role(parameters => undef);
+            $HORRIBLE_GC_AVOIDANCE_HACK{ $role->name } = $role;
+            return $role->name;
+        }
+
+        return $class;
+    }
 }
 
-package MooseX::Storage::Base;
-use Moose::Role;
+sub _injected_storage_role_generator {
+    my %params = @_;
+
+    $params{base} = '=MooseX::Storage::Basic' unless defined $params{base};
+
+    my @roles = __PACKAGE__->_expand_role(Base => $params{base});
 
-requires 'pack';
-requires 'unpack';
+    # NOTE:
+    # you don't have to have a format
+    # role, this just means you dont
+    # get anything other than pack/unpack
+    push @roles, __PACKAGE__->_expand_role(Format => $params{format});
 
-requires 'freeze';
-requires 'thaw';
+    # NOTE:
+    # many IO roles don't make sense unless
+    # you have also have a format role chosen
+    # too, the exception being StorableFile
+    #
+    # NOTE:
+    # we dont need this code anymore, cause
+    # the role composition will catch it for
+    # us. This allows the StorableFile to work
+    #(exists $params{'format'})
+    #    || confess "You must specify a format role in order to use an IO role";
+    push @roles, __PACKAGE__->_expand_role(IO => $params{io});
 
-requires 'load';
-requires 'store';
+    # Note:
+    # These traits alter the behaviour of the engine, the user can
+    # specify these per role-usage
+    for my $trait ( @{ $params{'traits'} ||= [] } ) {
+        push @roles, __PACKAGE__->_expand_role(Traits => $trait);
+    }
+
+    return @roles;
+}
 
 1;
 
@@ -29,4 +109,247 @@ __END__
 
 =pod
 
+=head1 NAME
+
+MooseX::Storage - A serialization framework for Moose classes
+
+=head1 SYNOPSIS
+
+  package Point;
+  use Moose;
+  use MooseX::Storage;
+
+  our $VERSION = '0.01';
+
+  with Storage('format' => 'JSON', 'io' => 'File');
+
+  has 'x' => (is => 'rw', isa => 'Int');
+  has 'y' => (is => 'rw', isa => 'Int');
+
+  1;
+
+  my $p = Point->new(x => 10, y => 10);
+
+  ## methods to pack/unpack an
+  ## object in perl data structures
+
+  # pack the class into a hash
+  $p->pack(); # { __CLASS__ => 'Point-0.01', x => 10, y => 10 }
+
+  # unpack the hash into a class
+  my $p2 = Point->unpack({ __CLASS__ => 'Point-0.01', x => 10, y => 10 });
+
+  ## methods to freeze/thaw into
+  ## a specified serialization format
+  ## (in this case JSON)
+
+  # pack the class into a JSON string
+  $p->freeze(); # { "__CLASS__" : "Point-0.01", "x" : 10, "y" : 10 }
+
+  # unpack the JSON string into a class
+  my $p2 = Point->thaw('{ "__CLASS__" : "Point-0.01", "x" : 10, "y" : 10 }');
+
+  ## methods to load/store a class
+  ## on the file system
+
+  $p->store('my_point.json');
+
+  my $p2 = Point->load('my_point.json');
+
+=head1 DESCRIPTION
+
+MooseX::Storage is a serialization framework for Moose, it provides
+a very flexible and highly pluggable way to serialize Moose classes
+to a number of different formats and styles.
+
+=head2 Important Note
+
+This is still an early release of this module, so use with caution.
+It's outward facing serialization API should be considered stable,
+but I still reserve the right to make tweaks if I need too. Anything
+beyond the basic pack/unpack, freeze/thaw and load/store should not
+be relied on.
+
+=head2 Levels of Serialization
+
+There are 3 levels to the serialization, each of which builds upon
+the other and each of which can be customized to the specific needs
+of your class.
+
+=over 4
+
+=item B<base>
+
+The first (base) level is C<pack> and C<unpack>. In this level the
+class is serialized into a Perl HASH reference, it is tagged with the
+class name and each instance attribute is stored. Very simple.
+
+This level is not optional, it is the bare minumum that
+MooseX::Storage provides and all other levels build on top of this.
+
+See L<MooseX::Storage::Basic> for the fundamental implementation and
+options to C<pack> and C<unpack>
+
+=item B<format>
+
+The second (format) level is C<freeze> and C<thaw>. In this level the
+output of C<pack> is sent to C<freeze> or the output of C<thaw> is sent
+to C<unpack>. This levels primary role is to convert to and from the
+specific serialization format and Perl land.
+
+This level is optional, if you don't want/need it, you don't have to
+have it. You can just use C<pack>/C<unpack> instead.
+
+=item B<io>
+
+The third (io) level is C<load> and C<store>. In this level we are reading
+and writing data to file/network/database/etc.
+
+This level is also optional, in most cases it does require a C<format> role
+to also be used, the exception being the C<StorableFile> role.
+
+=back
+
+=head2 Behaviour modifiers
+
+The serialization behaviour can be changed by supplying C<traits>.
+This can be done as follows:
+
+  use MooseX::Storage;
+  with Storage( traits => [Trait1, Trait2,...] );
+
+The following traits are currently bundled with C<MooseX::Storage>:
+
+=over 4
+
+=item OnlyWhenBuilt
+
+Only attributes that have been built (ie, where the predicate returns
+'true') will be serialized. This avoids any potentially expensive computations.
+
+See L<MooseX::Storage::Traits::OnlyWhenBuilt> for details.
+
+=back
+
+=head2 How we serialize
+
+There are always limits to any serialization framework, there are just
+some things which are really difficult to serialize properly and some
+things which cannot be serialized at all.
+
+=head2 What can be serialized?
+
+Currently only numbers, string, ARRAY refs, HASH refs and other
+MooseX::Storage enabled objects are supported.
+
+With Array and Hash references the first level down is inspected and
+any objects found are serialized/deserialized for you. We do not do
+this recusively by default, however this feature may become an
+option eventually.
+
+The specific serialize/deserialize routine is determined by the
+Moose type constraint a specific attribute has. In most cases subtypes
+of the supported types are handled correctly, and there is a facility
+for adding handlers for custom types as well. This will get documented
+eventually, but it is currently still in development.
+
+=head2 What can not be serialized?
+
+We do not support CODE references yet, but this support might be added
+in using B::Deparse or some other deep magic.
+
+Scalar refs are not supported, mostly because there is no way to know
+if the value being referenced will be there when the object is inflated.
+I highly doubt will be ever support this in a general sense, but it
+would be possible to add this yourself for a small specific case.
+
+Circular references are specifically disallowed, however if you break
+the cycles yourself then re-assemble them later you can get around this.
+The reason we disallow circular refs is because they are not always supported
+in all formats we use, and they tend to be very tricky to do for all
+possible cases. It is almost always something you want to have tight control
+over anyway.
+
+=head1 CAVEAT
+
+This is B<not> a persistence framework; changes to your object after
+you load or store it will not be reflected in the stored class.
+
+=head1 EXPORTS
+
+=over 4
+
+=item B<Storage (%options)>
+
+This module will export the C<Storage> method and can be used to
+load a specific set of MooseX::Storage roles to implement a specific
+combination of features. It is meant to make things easier, but it
+is by no means the only way. You can still compose your roles by
+hand if you like.
+
+By default, options are assumed to be short forms.  For example, this:
+
+  Storage(format => 'JSON');
+
+...will result in looking for MooseX::Storage::Format::JSON.  To use a role
+that is not under the default namespace prefix, start with an equal sign:
+
+  Storage(format => '=My::Private::JSONFormat');
+
+To use a parameterized role (for which, see L<MooseX::Role::Parameterized>) you
+can pass an arrayref of the role name (in short or long form, as above) and its
+parameters:
+
+  Storage(format => [ JSONpm => { json_opts => { pretty => 1 } } ]);
+
+=back
+
+=head1 METHODS
+
+=over 4
+
+=item B<import>
+
+=back
+
+=head2 Introspection
+
+=over 4
+
+=item B<meta>
+
+=back
+
+=head1 TODO
+
+This module needs docs and probably a Cookbook of some kind as well.
+This is an early release, so that is my excuse for now :)
+
+For the time being, please read the tests and feel free to email me
+if you have any questions. This module can also be discussed on IRC
+in the #moose channel on irc.perl.org.
+
+=head1 BUGS
+
+All complex software has bugs lurking in it, and this module is no
+exception. If you find a bug please either email me, or add the bug
+to cpan-RT.
+
+=head1 AUTHOR
+
+Chris Prather E<lt>chris.prather@iinteractive.comE<gt>
+
+Stevan Little E<lt>stevan.little@iinteractive.comE<gt>
+
+Yuval Kogman E<lt>yuval.kogman@iinteractive.comE<gt>
+
+=head1 COPYRIGHT AND LICENSE
+
+Copyright 2007-2008 by Infinity Interactive, Inc.
+
+L<http://www.iinteractive.com>
+
+This library is free software; you can redistribute it and/or modify
+it under the same terms as Perl itself.
+
 =cut