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.\" ========================================================================
.\"
.IX Title "KiokuDB::LiveObjects 3pm"
.TH KiokuDB::LiveObjects 3pm "2014-03-25" "perl v5.18.2" "User Contributed Perl Documentation"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
KiokuDB::LiveObjects \- Live object set tracking
.SH "VERSION"
.IX Header "VERSION"
version 0.57
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
.Vb 1
\&    $live_objects\->insert( $entry => $object );
\&
\&    $live_objects\->insert( $id => $object );
\&
\&    my $id = $live_objects\->object_to_id( $object );
\&
\&    my $obj = $live_objects\->id_to_object( $id );
\&
\&    my $scope = $live_objects\->new_scope;
.Ve
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
This object keeps track of the set of live objects, their associated IDs, and
the storage entries.
.SH "ATTRIBUTES"
.IX Header "ATTRIBUTES"
.IP "clear_leaks" 4
.IX Item "clear_leaks"
Boolean. Defaults to false.
.Sp
If true, when the last known scope is removed but some objects are still live
they will be removed from the live object set.
.Sp
Note that this does \fB\s-1NOT\s0\fR prevent leaks (memory cannot be reclaimed), it
merely prevents stale objects from staying loaded.
.IP "leak_tracker" 4
.IX Item "leak_tracker"
This is a coderef or object.
.Sp
If any objects are leaked (see \f(CW\*(C`clear_leaks\*(C'\fR) then the this can be used to
report them, or to break the circular structure.
.Sp
When an object is provided the \f(CW\*(C`leaked_objects\*(C'\fR method is called. The coderef
is simply invoked with the objects as arguments.
.Sp
Triggered after \f(CW\*(C`clear_leaks\*(C'\fR causes \f(CW\*(C`clear\*(C'\fR to be called.
.Sp
For example, to break cycles you can use Data::Structure::Util's
\&\f(CW\*(C`circular_off\*(C'\fR function:
.Sp
.Vb 1
\&    use Data::Structure::Util qw(circular_off);
\&
\&    $dir\->live_objects\->leak_tracker(sub {
\&        my @leaked_objects = @_;
\&        circular_off($_) for @leaked_objects;
\&    });
.Ve
.IP "keep_entries" 4
.IX Item "keep_entries"
\&\fB\s-1EXPERIMENTAL\s0\fR
.Sp
When true (the default), KiokuDB::Entries loaded from the backend or created
by the collapser are kept around.
.Sp
This results in a considerable memory overhead, so it's no longer required.
.SH "METHODS"
.IX Header "METHODS"
.IP "insert" 4
.IX Item "insert"
Takes pairs, id or entry as the key, and object as the value, registering the
objects.
.IP "objects_to_ids" 4
.IX Item "objects_to_ids"
.PD 0
.IP "object_to_id" 4
.IX Item "object_to_id"
.PD
Given objects, returns their IDs, or undef for objects which not registered.
.IP "objects_to_entries" 4
.IX Item "objects_to_entries"
.PD 0
.IP "object_to_entry" 4
.IX Item "object_to_entry"
.PD
Given objects, find the corresponding entries.
.IP "ids_to_objects" 4
.IX Item "ids_to_objects"
.PD 0
.IP "id_to_object" 4
.IX Item "id_to_object"
.PD
Given IDs, find the corresponding objects.
.IP "ids_to_entries" 4
.IX Item "ids_to_entries"
Given IDs, find the corresponding entries.
.IP "update_entries" 4
.IX Item "update_entries"
Given entries, replaces the live entries of the corresponding objects with the
newly updated ones.
.Sp
The objects must already be in the live object set.
.Sp
This method is called on a successful transaction commit.
.IP "new_scope" 4
.IX Item "new_scope"
Creates a new KiokuDB::LiveObjects::Scope, with the current scope as its
parent.
.IP "current_scope" 4
.IX Item "current_scope"
The current KiokuDB::LiveObjects::Scope instance.
.Sp
This is the scope into which newly registered objects are pushed.
.IP "new_txn" 4
.IX Item "new_txn"
Creates a new KiokuDB::LiveObjects::TXNScope, with the current txn scope as
its parent.
.IP "txn_scope" 4
.IX Item "txn_scope"
The current KiokuDB::LiveObjects::TXNScope.
.IP "clear" 4
.IX Item "clear"
Forces a clear of the live object set.
.Sp
This removes all objects and entries, and can be useful in the case of leaks
(to prevent false positives on lookups).
.Sp
Note that this does not actually break the circular structures, so the leak is
unresolved, but the objects are no longer considered live by the KiokuDB instance.
.IP "live_entries" 4
.IX Item "live_entries"
.PD 0
.IP "live_objects" 4
.IX Item "live_objects"
.IP "live_ids" 4
.IX Item "live_ids"
.PD
Enumerates the live entries, objects or ids.
.IP "rollback_entries" 4
.IX Item "rollback_entries"
Called by \*(L"rollback\*(R" in KiokuDB::LiveObjects::TXNScope.
.IP "remove" 4
.IX Item "remove"
Removes entries from the live object set.
.ie n .IP "remove_scope $scope" 4
.el .IP "remove_scope \f(CW$scope\fR" 4
.IX Item "remove_scope $scope"
Removes a scope from the set of known scopes.
.Sp
Also calls \f(CW\*(C`detach_scope\*(C'\fR, and calls \f(CW\*(C`KiokuDB::LiveObjects::Scope/clear\*(C'\fR on
the scope itself.
.ie n .IP "detach_scope $scope" 4
.el .IP "detach_scope \f(CW$scope\fR" 4
.IX Item "detach_scope $scope"
Detaches \f(CW$scope\fR if it's the current scope.
.Sp
This prevents \f(CW\*(C`push\*(C'\fR from being called on this scope object implicitly
anymore.
.SH "AUTHOR"
.IX Header "AUTHOR"
Yuval Kogman <nothingmuch@woobling.org>
.SH "COPYRIGHT AND LICENSE"
.IX Header "COPYRIGHT AND LICENSE"
This software is copyright (c) 2014 by Yuval Kogman, Infinity Interactive.
.PP
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.