[dbsrgits/DBM-Deep.git] / lib / DBM / Deep / Sector / File / Reference.pm

package DBM::Deep::Sector::File::Reference;

use 5.006_000;

use strict;
use warnings FATAL => 'all';

use base qw( DBM::Deep::Sector::File::Data );

my $STALE_SIZE = 2;

# Please refer to the pack() documentation for further information
my %StP = (
    1 => 'C', # Unsigned char value (no order needed as it's just one byte)
    2 => 'n', # Unsigned short in "network" (big-endian) order
    4 => 'N', # Unsigned long in "network" (big-endian) order
    8 => 'Q', # Usigned quad (no order specified, presumably machine-dependent)
);

sub _init {
    my $self = shift;

    my $e = $self->engine;

    unless ( $self->offset ) {
        my $classname = Scalar::Util::blessed( delete $self->{data} );
        my $leftover = $self->size - $self->base_size - 3 * $e->byte_size;

        my $class_offset = 0;
        if ( defined $classname ) {
            my $class_sector = DBM::Deep::Sector::File::Scalar->new({
                engine => $e,
                data   => $classname,
            });
            $class_offset = $class_sector->offset;
        }

        $self->{offset} = $e->_request_data_sector( $self->size );
        $e->storage->print_at( $self->offset, $self->type ); # Sector type
        # Skip staleness counter
        $e->storage->print_at( $self->offset + $self->base_size,
            pack( $StP{$e->byte_size}, 0 ),             # Index/BList loc
            pack( $StP{$e->byte_size}, $class_offset ), # Classname loc
            pack( $StP{$e->byte_size}, 1 ),             # Initial refcount
            chr(0) x $leftover,                         # Zero-fill the rest
        );
    }
    else {
        $self->{type} = $e->storage->read_at( $self->offset, 1 );
    }

    $self->{staleness} = unpack(
        $StP{$STALE_SIZE},
        $e->storage->read_at( $self->offset + $e->SIG_SIZE, $STALE_SIZE ),
    );

    return;
}

sub staleness { $_[0]{staleness} }

sub get_data_location_for {
    my $self = shift;
    my ($args) = @_;

    # Assume that the head is not allowed unless otherwise specified.
    $args->{allow_head} = 0 unless exists $args->{allow_head};

    # Assume we don't create a new blist location unless otherwise specified.
    $args->{create} = 0 unless exists $args->{create};

    my $blist = $self->get_bucket_list({
        key_md5 => $args->{key_md5},
        key => $args->{key},
        create  => $args->{create},
    });
    return unless $blist && $blist->{found};

    # At this point, $blist knows where the md5 is. What it -doesn't- know yet
    # is whether or not this transaction has this key. That's part of the next
    # function call.
    my $location = $blist->get_data_location_for({
        allow_head => $args->{allow_head},
    }) or return;

    return $location;
}

sub get_data_for {
    my $self = shift;
    my ($args) = @_;

    my $location = $self->get_data_location_for( $args )
        or return;

    return DBM::Deep::Sector::File->load( $self->engine, $location );
}

sub write_data {
    my $self = shift;
    my ($args) = @_;

    my $blist = $self->get_bucket_list({
        key_md5 => $args->{key_md5},
        key => $args->{key},
        create  => 1,
    }) or DBM::Deep->_throw_error( "How did write_data fail (no blist)?!" );

    # Handle any transactional bookkeeping.
    if ( $self->engine->trans_id ) {
        if ( ! $blist->has_md5 ) {
            $blist->mark_deleted({
                trans_id => 0,
            });
        }
    }
    else {
        my @trans_ids = $self->engine->get_running_txn_ids;
        if ( $blist->has_md5 ) {
            if ( @trans_ids ) {
                my $old_value = $blist->get_data_for;
                foreach my $other_trans_id ( @trans_ids ) {
                    next if $blist->get_data_location_for({
                        trans_id   => $other_trans_id,
                        allow_head => 0,
                    });
                    $blist->write_md5({
                        trans_id => $other_trans_id,
                        key      => $args->{key},
                        key_md5  => $args->{key_md5},
                        value    => $old_value->clone,
                    });
                }
            }
        }
        else {
            if ( @trans_ids ) {
                foreach my $other_trans_id ( @trans_ids ) {
                    #XXX This doesn't seem to possible to ever happen . . .
                    next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
                    $blist->mark_deleted({
                        trans_id => $other_trans_id,
                    });
                }
            }
        }
    }

    #XXX Is this safe to do transactionally?
    # Free the place we're about to write to.
    if ( $blist->get_data_location_for({ allow_head => 0 }) ) {
        $blist->get_data_for({ allow_head => 0 })->free;
    }

    $blist->write_md5({
        key      => $args->{key},
        key_md5  => $args->{key_md5},
        value    => $args->{value},
    });
}

sub delete_key {
    my $self = shift;
    my ($args) = @_;

    # This can return nothing if we are deleting an entry in a hashref that was
    # auto-vivified as part of the delete process. For example:
    #     my $x = {};
    #     delete $x->{foo}{bar};
    my $blist = $self->get_bucket_list({
        key_md5 => $args->{key_md5},
    }) or return;

    # Save the location so that we can free the data
    my $location = $blist->get_data_location_for({
        allow_head => 0,
    });
    my $old_value = $location && DBM::Deep::Sector::File->load( $self->engine, $location );

    my @trans_ids = $self->engine->get_running_txn_ids;

    # If we're the HEAD and there are running txns, then we need to clone this value to the other
    # transactions to preserve Isolation.
    if ( $self->engine->trans_id == 0 ) {
        if ( @trans_ids ) {
            foreach my $other_trans_id ( @trans_ids ) {
                next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
                $blist->write_md5({
                    trans_id => $other_trans_id,
                    key      => $args->{key},
                    key_md5  => $args->{key_md5},
                    value    => $old_value->clone,
                });
            }
        }
    }

    my $data;
    if ( @trans_ids ) {
        $blist->mark_deleted( $args );

        if ( $old_value ) {
            $data = $old_value->data({ export => 1 });
            $old_value->free;
        }
    }
    else {
        $data = $blist->delete_md5( $args );
    }

    return $data;
}

sub get_blist_loc {
    my $self = shift;

    my $e = $self->engine;
    my $blist_loc = $e->storage->read_at( $self->offset + $self->base_size, $e->byte_size );
    return unpack( $StP{$e->byte_size}, $blist_loc );
}

sub get_bucket_list {
    my $self = shift;
    my ($args) = @_;
    $args ||= {};

    # XXX Add in check here for recycling?

    my $engine = $self->engine;

    my $blist_loc = $self->get_blist_loc;

    # There's no index or blist yet
    unless ( $blist_loc ) {
        return unless $args->{create};

        my $blist = DBM::Deep::Sector::File::BucketList->new({
            engine  => $engine,
            key_md5 => $args->{key_md5},
        });

        $engine->storage->print_at( $self->offset + $self->base_size,
            pack( $StP{$engine->byte_size}, $blist->offset ),
        );

        return $blist;
    }

    my $sector = DBM::Deep::Sector::File->load( $engine, $blist_loc )
        or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
    my $i = 0;
    my $last_sector = undef;
    while ( $sector->isa( 'DBM::Deep::Sector::File::Index' ) ) {
        $blist_loc = $sector->get_entry( ord( substr( $args->{key_md5}, $i++, 1 ) ) );
        $last_sector = $sector;
        if ( $blist_loc ) {
            $sector = DBM::Deep::Sector::File->load( $engine, $blist_loc )
                or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
        }
        else {
            $sector = undef;
            last;
        }
    }

    # This means we went through the Index sector(s) and found an empty slot
    unless ( $sector ) {
        return unless $args->{create};

        DBM::Deep->_throw_error( "No last_sector when attempting to build a new entry" )
            unless $last_sector;

        my $blist = DBM::Deep::Sector::File::BucketList->new({
            engine  => $engine,
            key_md5 => $args->{key_md5},
        });

        $last_sector->set_entry( ord( substr( $args->{key_md5}, $i - 1, 1 ) ) => $blist->offset );

        return $blist;
    }

    $sector->find_md5( $args->{key_md5} );

    # See whether or not we need to reindex the bucketlist
    # Yes, the double-braces are there for a reason. if() doesn't create a redo-able block,
    # so we have to create a bare block within the if() for redo-purposes. Patch and idea
    # submitted by sprout@cpan.org. -RobK, 2008-01-09
    if ( !$sector->has_md5 && $args->{create} && $sector->{idx} == -1 ) {{
        my $redo;

        my $new_index = DBM::Deep::Sector::File::Index->new({
            engine => $engine,
        });

        my %blist_cache;
        #XXX q.v. the comments for this function.
        foreach my $entry ( $sector->chopped_up ) {
            my ($spot, $md5) = @{$entry};
            my $idx = ord( substr( $md5, $i, 1 ) );

            # XXX This is inefficient
            my $blist = $blist_cache{$idx}
                ||= DBM::Deep::Sector::File::BucketList->new({
                    engine => $engine,
                });

            $new_index->set_entry( $idx => $blist->offset );

            my $new_spot = $blist->write_at_next_open( $md5 );
            $engine->reindex_entry( $spot => $new_spot );
        }

        # Handle the new item separately.
        {
            my $idx = ord( substr( $args->{key_md5}, $i, 1 ) );

            # If all the previous blist's items have been thrown into one
            # blist and the new item belongs in there too, we need
            # another index.
            if ( keys %blist_cache == 1 and each %blist_cache == $idx ) {
                ++$i, ++$redo;
            } else {
                my $blist = $blist_cache{$idx}
                    ||= DBM::Deep::Sector::File::BucketList->new({
                        engine => $engine,
                    });
    
                $new_index->set_entry( $idx => $blist->offset );
    
                #XXX THIS IS HACKY!
                $blist->find_md5( $args->{key_md5} );
                $blist->write_md5({
                    key     => $args->{key},
                    key_md5 => $args->{key_md5},
                    value   => DBM::Deep::Sector::File::Null->new({
                        engine => $engine,
                        data   => undef,
                    }),
                });
            }
#            my $blist = $blist_cache{$idx}
#                ||= DBM::Deep::Sector::File::BucketList->new({
#                    engine => $engine,
#                });
#
#            $new_index->set_entry( $idx => $blist->offset );
#
#            #XXX THIS IS HACKY!
#            $blist->find_md5( $args->{key_md5} );
#            $blist->write_md5({
#                key     => $args->{key},
#                key_md5 => $args->{key_md5},
#                value   => DBM::Deep::Sector::File::Null->new({
#                    engine => $engine,
#                    data   => undef,
#                }),
#            });
        }

        if ( $last_sector ) {
            $last_sector->set_entry(
                ord( substr( $args->{key_md5}, $i - 1, 1 ) ),
                $new_index->offset,
            );
        } else {
            $engine->storage->print_at( $self->offset + $self->base_size,
                pack( $StP{$engine->byte_size}, $new_index->offset ),
            );
        }

        $sector->clear;
        $sector->free;

        if ( $redo ) {
            (undef, $sector) = %blist_cache;
            $last_sector = $new_index;
            redo;
        }

        $sector = $blist_cache{ ord( substr( $args->{key_md5}, $i, 1 ) ) };
        $sector->find_md5( $args->{key_md5} );
    }}

    return $sector;
}

sub get_class_offset {
    my $self = shift;

    my $e = $self->engine;
    return unpack(
        $StP{$e->byte_size},
        $e->storage->read_at(
            $self->offset + $self->base_size + 1 * $e->byte_size, $e->byte_size,
        ),
    );
}

sub get_classname {
    my $self = shift;

    my $class_offset = $self->get_class_offset;

    return unless $class_offset;

    return DBM::Deep::Sector::File->load( $self->engine, $class_offset )->data;
}

sub data {
    my $self = shift;
    my ($args) = @_;
    $args ||= {};

    my $obj;
    unless ( $obj = $self->engine->cache->{ $self->offset } ) {
        $obj = DBM::Deep->new({
            type        => $self->type,
            base_offset => $self->offset,
            staleness   => $self->staleness,
            storage     => $self->engine->storage,
            engine      => $self->engine,
        });

        if ( $self->engine->storage->{autobless} ) {
            my $classname = $self->get_classname;
            if ( defined $classname ) {
                bless $obj, $classname;
            }
        }

        $self->engine->cache->{$self->offset} = $obj;
    }

    # We're not exporting, so just return.
    unless ( $args->{export} ) {
        return $obj;
    }

    # We shouldn't export if this is still referred to.
    if ( $self->get_refcount > 1 ) {
        return $obj;
    }

    return $obj->export;
}

sub free {
    my $self = shift;

    # We're not ready to be removed yet.
    if ( $self->decrement_refcount > 0 ) {
        return;
    }

    # Rebless the object into DBM::Deep::Null.
    eval { %{ $self->engine->cache->{ $self->offset } } = (); };
    eval { @{ $self->engine->cache->{ $self->offset } } = (); };
    bless $self->engine->cache->{ $self->offset }, 'DBM::Deep::Null';
    delete $self->engine->cache->{ $self->offset };

    my $blist_loc = $self->get_blist_loc;
    DBM::Deep::Sector::File->load( $self->engine, $blist_loc )->free if $blist_loc;

    my $class_loc = $self->get_class_offset;
    DBM::Deep::Sector::File->load( $self->engine, $class_loc )->free if $class_loc;

    $self->SUPER::free();
}

sub increment_refcount {
    my $self = shift;

    my $refcount = $self->get_refcount;

    $refcount++;

    $self->write_refcount( $refcount );

    return $refcount;
}

sub decrement_refcount {
    my $self = shift;

    my $refcount = $self->get_refcount;

    $refcount--;

    $self->write_refcount( $refcount );

    return $refcount;
}

sub get_refcount {
    my $self = shift;

    my $e = $self->engine;
    return unpack(
        $StP{$e->byte_size},
        $e->storage->read_at(
            $self->offset + $self->base_size + 2 * $e->byte_size, $e->byte_size,
        ),
    );
}

sub write_refcount {
    my $self = shift;
    my ($num) = @_;

    my $e = $self->engine;
    $e->storage->print_at(
        $self->offset + $self->base_size + 2 * $e->byte_size,
        pack( $StP{$e->byte_size}, $num ),
    );
}

1;
__END__
Commit	Line	Data
2c70efe1	1	package DBM::Deep::Sector::File::Reference;
f0276afb	2
	3	use 5.006_000;
	4
	5	use strict;
	6	use warnings FATAL => 'all';
	7
2c70efe1	8	use base qw( DBM::Deep::Sector::File::Data );
f0276afb	9
5ae752e2	10	my $STALE_SIZE = 2;
	11
	12	# Please refer to the pack() documentation for further information
	13	my %StP = (
	14	1 => 'C', # Unsigned char value (no order needed as it's just one byte)
	15	2 => 'n', # Unsigned short in "network" (big-endian) order
	16	4 => 'N', # Unsigned long in "network" (big-endian) order
	17	8 => 'Q', # Usigned quad (no order specified, presumably machine-dependent)
	18	);
	19
f0276afb	20	sub _init {
	21	my $self = shift;
	22
	23	my $e = $self->engine;
	24
	25	unless ( $self->offset ) {
	26	my $classname = Scalar::Util::blessed( delete $self->{data} );
	27	my $leftover = $self->size - $self->base_size - 3 * $e->byte_size;
	28
	29	my $class_offset = 0;
	30	if ( defined $classname ) {
2c70efe1	31	my $class_sector = DBM::Deep::Sector::File::Scalar->new({
f0276afb	32	engine => $e,
	33	data => $classname,
	34	});
	35	$class_offset = $class_sector->offset;
	36	}
	37
	38	$self->{offset} = $e->_request_data_sector( $self->size );
	39	$e->storage->print_at( $self->offset, $self->type ); # Sector type
	40	# Skip staleness counter
	41	$e->storage->print_at( $self->offset + $self->base_size,
	42	pack( $StP{$e->byte_size}, 0 ), # Index/BList loc
	43	pack( $StP{$e->byte_size}, $class_offset ), # Classname loc
	44	pack( $StP{$e->byte_size}, 1 ), # Initial refcount
	45	chr(0) x $leftover, # Zero-fill the rest
	46	);
	47	}
	48	else {
	49	$self->{type} = $e->storage->read_at( $self->offset, 1 );
	50	}
	51
	52	$self->{staleness} = unpack(
	53	$StP{$STALE_SIZE},
	54	$e->storage->read_at( $self->offset + $e->SIG_SIZE, $STALE_SIZE ),
	55	);
	56
	57	return;
	58	}
	59
	60	sub staleness { $_[0]{staleness} }
	61
	62	sub get_data_location_for {
	63	my $self = shift;
	64	my ($args) = @_;
	65
	66	# Assume that the head is not allowed unless otherwise specified.
	67	$args->{allow_head} = 0 unless exists $args->{allow_head};
	68
	69	# Assume we don't create a new blist location unless otherwise specified.
	70	$args->{create} = 0 unless exists $args->{create};
	71
	72	my $blist = $self->get_bucket_list({
	73	key_md5 => $args->{key_md5},
	74	key => $args->{key},
	75	create => $args->{create},
	76	});
	77	return unless $blist && $blist->{found};
	78
	79	# At this point, $blist knows where the md5 is. What it -doesn't- know yet
	80	# is whether or not this transaction has this key. That's part of the next
	81	# function call.
	82	my $location = $blist->get_data_location_for({
	83	allow_head => $args->{allow_head},
	84	}) or return;
	85
	86	return $location;
	87	}
	88
	89	sub get_data_for {
	90	my $self = shift;
	91	my ($args) = @_;
	92
	93	my $location = $self->get_data_location_for( $args )
	94	or return;
	95
2c70efe1	96	return DBM::Deep::Sector::File->load( $self->engine, $location );
f0276afb	97	}
	98
	99	sub write_data {
	100	my $self = shift;
	101	my ($args) = @_;
	102
	103	my $blist = $self->get_bucket_list({
	104	key_md5 => $args->{key_md5},
	105	key => $args->{key},
	106	create => 1,
	107	}) or DBM::Deep->_throw_error( "How did write_data fail (no blist)?!" );
	108
	109	# Handle any transactional bookkeeping.
	110	if ( $self->engine->trans_id ) {
	111	if ( ! $blist->has_md5 ) {
	112	$blist->mark_deleted({
	113	trans_id => 0,
	114	});
	115	}
	116	}
	117	else {
	118	my @trans_ids = $self->engine->get_running_txn_ids;
	119	if ( $blist->has_md5 ) {
	120	if ( @trans_ids ) {
	121	my $old_value = $blist->get_data_for;
	122	foreach my $other_trans_id ( @trans_ids ) {
	123	next if $blist->get_data_location_for({
	124	trans_id => $other_trans_id,
	125	allow_head => 0,
	126	});
	127	$blist->write_md5({
	128	trans_id => $other_trans_id,
	129	key => $args->{key},
	130	key_md5 => $args->{key_md5},
	131	value => $old_value->clone,
	132	});
	133	}
	134	}
	135	}
	136	else {
	137	if ( @trans_ids ) {
	138	foreach my $other_trans_id ( @trans_ids ) {
	139	#XXX This doesn't seem to possible to ever happen . . .
	140	next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
	141	$blist->mark_deleted({
	142	trans_id => $other_trans_id,
	143	});
	144	}
	145	}
	146	}
	147	}
	148
	149	#XXX Is this safe to do transactionally?
	150	# Free the place we're about to write to.
	151	if ( $blist->get_data_location_for({ allow_head => 0 }) ) {
	152	$blist->get_data_for({ allow_head => 0 })->free;
	153	}
	154
	155	$blist->write_md5({
	156	key => $args->{key},
	157	key_md5 => $args->{key_md5},
	158	value => $args->{value},
	159	});
	160	}
161
162	sub delete_key {
163	my $self = shift;
164	my ($args) = @_;
165
c803879b	166	# This can return nothing if we are deleting an entry in a hashref that was
	167	# auto-vivified as part of the delete process. For example:
	168	# my $x = {};
	169	# delete $x->{foo}{bar};
f0276afb	170	my $blist = $self->get_bucket_list({
f0276afb	171	key_md5 => $args->{key_md5},
c803879b	172	}) or return;
f0276afb	173
	174	# Save the location so that we can free the data
	175	my $location = $blist->get_data_location_for({
	176	allow_head => 0,
	177	});
2c70efe1	178	my $old_value = $location && DBM::Deep::Sector::File->load( $self->engine, $location );
f0276afb	179
	180	my @trans_ids = $self->engine->get_running_txn_ids;
	181
	182	# If we're the HEAD and there are running txns, then we need to clone this value to the other
	183	# transactions to preserve Isolation.
	184	if ( $self->engine->trans_id == 0 ) {
	185	if ( @trans_ids ) {
	186	foreach my $other_trans_id ( @trans_ids ) {
	187	next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
	188	$blist->write_md5({
	189	trans_id => $other_trans_id,
	190	key => $args->{key},
	191	key_md5 => $args->{key_md5},
	192	value => $old_value->clone,
	193	});
	194	}
	195	}
	196	}
	197
	198	my $data;
	199	if ( @trans_ids ) {
	200	$blist->mark_deleted( $args );
	201
	202	if ( $old_value ) {
	203	$data = $old_value->data({ export => 1 });
	204	$old_value->free;
	205	}
	206	}
	207	else {
	208	$data = $blist->delete_md5( $args );
	209	}
	210
	211	return $data;
	212	}
	213
	214	sub get_blist_loc {
	215	my $self = shift;
	216
	217	my $e = $self->engine;
	218	my $blist_loc = $e->storage->read_at( $self->offset + $self->base_size, $e->byte_size );
	219	return unpack( $StP{$e->byte_size}, $blist_loc );
	220	}
	221
	222	sub get_bucket_list {
	223	my $self = shift;
	224	my ($args) = @_;
	225	$args \|\|= {};
	226
	227	# XXX Add in check here for recycling?
	228
	229	my $engine = $self->engine;
	230
	231	my $blist_loc = $self->get_blist_loc;
	232
	233	# There's no index or blist yet
	234	unless ( $blist_loc ) {
	235	return unless $args->{create};
	236
2c70efe1	237	my $blist = DBM::Deep::Sector::File::BucketList->new({
f0276afb	238	engine => $engine,
	239	key_md5 => $args->{key_md5},
	240	});
	241
	242	$engine->storage->print_at( $self->offset + $self->base_size,
	243	pack( $StP{$engine->byte_size}, $blist->offset ),
	244	);
	245
	246	return $blist;
	247	}
	248
2c70efe1	249	my $sector = DBM::Deep::Sector::File->load( $engine, $blist_loc )
f0276afb	250	or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
	251	my $i = 0;
	252	my $last_sector = undef;
2c70efe1	253	while ( $sector->isa( 'DBM::Deep::Sector::File::Index' ) ) {
f0276afb	254	$blist_loc = $sector->get_entry( ord( substr( $args->{key_md5}, $i++, 1 ) ) );
	255	$last_sector = $sector;
	256	if ( $blist_loc ) {
2c70efe1	257	$sector = DBM::Deep::Sector::File->load( $engine, $blist_loc )
f0276afb	258	or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
	259	}
	260	else {
	261	$sector = undef;
	262	last;
	263	}
	264	}
	265
	266	# This means we went through the Index sector(s) and found an empty slot
	267	unless ( $sector ) {
	268	return unless $args->{create};
	269
	270	DBM::Deep->_throw_error( "No last_sector when attempting to build a new entry" )
	271	unless $last_sector;
	272
2c70efe1	273	my $blist = DBM::Deep::Sector::File::BucketList->new({
f0276afb	274	engine => $engine,
	275	key_md5 => $args->{key_md5},
	276	});
	277
	278	$last_sector->set_entry( ord( substr( $args->{key_md5}, $i - 1, 1 ) ) => $blist->offset );
	279
	280	return $blist;
	281	}
	282
	283	$sector->find_md5( $args->{key_md5} );
	284
	285	# See whether or not we need to reindex the bucketlist
	286	# Yes, the double-braces are there for a reason. if() doesn't create a redo-able block,
	287	# so we have to create a bare block within the if() for redo-purposes. Patch and idea
	288	# submitted by sprout@cpan.org. -RobK, 2008-01-09
	289	if ( !$sector->has_md5 && $args->{create} && $sector->{idx} == -1 ) {{
	290	my $redo;
	291
2c70efe1	292	my $new_index = DBM::Deep::Sector::File::Index->new({
f0276afb	293	engine => $engine,
	294	});
	295
	296	my %blist_cache;
	297	#XXX q.v. the comments for this function.
	298	foreach my $entry ( $sector->chopped_up ) {
	299	my ($spot, $md5) = @{$entry};
	300	my $idx = ord( substr( $md5, $i, 1 ) );
	301
	302	# XXX This is inefficient
	303	my $blist = $blist_cache{$idx}
2c70efe1	304	\|\|= DBM::Deep::Sector::File::BucketList->new({
f0276afb	305	engine => $engine,
	306	});
	307
	308	$new_index->set_entry( $idx => $blist->offset );
	309
	310	my $new_spot = $blist->write_at_next_open( $md5 );
	311	$engine->reindex_entry( $spot => $new_spot );
	312	}
	313
	314	# Handle the new item separately.
	315	{
	316	my $idx = ord( substr( $args->{key_md5}, $i, 1 ) );
	317
	318	# If all the previous blist's items have been thrown into one
	319	# blist and the new item belongs in there too, we need
	320	# another index.
	321	if ( keys %blist_cache == 1 and each %blist_cache == $idx ) {
	322	++$i, ++$redo;
	323	} else {
	324	my $blist = $blist_cache{$idx}
2c70efe1	325	\|\|= DBM::Deep::Sector::File::BucketList->new({
f0276afb	326	engine => $engine,
	327	});
	328
	329	$new_index->set_entry( $idx => $blist->offset );
	330
	331	#XXX THIS IS HACKY!
	332	$blist->find_md5( $args->{key_md5} );
	333	$blist->write_md5({
	334	key => $args->{key},
	335	key_md5 => $args->{key_md5},
2c70efe1	336	value => DBM::Deep::Sector::File::Null->new({
f0276afb	337	engine => $engine,
	338	data => undef,
	339	}),
	340	});
	341	}
	342	# my $blist = $blist_cache{$idx}
2c70efe1	343	# \|\|= DBM::Deep::Sector::File::BucketList->new({
f0276afb	344	# engine => $engine,
	345	# });
	346	#
	347	# $new_index->set_entry( $idx => $blist->offset );
	348	#
	349	# #XXX THIS IS HACKY!
	350	# $blist->find_md5( $args->{key_md5} );
	351	# $blist->write_md5({
	352	# key => $args->{key},
	353	# key_md5 => $args->{key_md5},
2c70efe1	354	# value => DBM::Deep::Sector::File::Null->new({
f0276afb	355	# engine => $engine,
	356	# data => undef,
	357	# }),
	358	# });
	359	}
	360
	361	if ( $last_sector ) {
	362	$last_sector->set_entry(
	363	ord( substr( $args->{key_md5}, $i - 1, 1 ) ),
	364	$new_index->offset,
	365	);
	366	} else {
	367	$engine->storage->print_at( $self->offset + $self->base_size,
	368	pack( $StP{$engine->byte_size}, $new_index->offset ),
	369	);
	370	}
	371
	372	$sector->clear;
	373	$sector->free;
	374
	375	if ( $redo ) {
	376	(undef, $sector) = %blist_cache;
	377	$last_sector = $new_index;
	378	redo;
	379	}
	380
	381	$sector = $blist_cache{ ord( substr( $args->{key_md5}, $i, 1 ) ) };
	382	$sector->find_md5( $args->{key_md5} );
	383	}}
	384
	385	return $sector;
	386	}
	387
	388	sub get_class_offset {
	389	my $self = shift;
	390
	391	my $e = $self->engine;
	392	return unpack(
	393	$StP{$e->byte_size},
	394	$e->storage->read_at(
	395	$self->offset + $self->base_size + 1 * $e->byte_size, $e->byte_size,
	396	),
	397	);
	398	}
	399
	400	sub get_classname {
	401	my $self = shift;
	402
	403	my $class_offset = $self->get_class_offset;
	404
	405	return unless $class_offset;
	406
2c70efe1	407	return DBM::Deep::Sector::File->load( $self->engine, $class_offset )->data;
f0276afb	408	}
	409
	410	sub data {
	411	my $self = shift;
	412	my ($args) = @_;
	413	$args \|\|= {};
	414
	415	my $obj;
	416	unless ( $obj = $self->engine->cache->{ $self->offset } ) {
	417	$obj = DBM::Deep->new({
	418	type => $self->type,
	419	base_offset => $self->offset,
	420	staleness => $self->staleness,
	421	storage => $self->engine->storage,
	422	engine => $self->engine,
	423	});
	424
	425	if ( $self->engine->storage->{autobless} ) {
	426	my $classname = $self->get_classname;
	427	if ( defined $classname ) {
	428	bless $obj, $classname;
	429	}
	430	}
	431
	432	$self->engine->cache->{$self->offset} = $obj;
	433	}
	434
	435	# We're not exporting, so just return.
	436	unless ( $args->{export} ) {
	437	return $obj;
	438	}
	439
	440	# We shouldn't export if this is still referred to.
	441	if ( $self->get_refcount > 1 ) {
	442	return $obj;
	443	}
	444
	445	return $obj->export;
	446	}
	447
	448	sub free {
	449	my $self = shift;
	450
	451	# We're not ready to be removed yet.
	452	if ( $self->decrement_refcount > 0 ) {
	453	return;
	454	}
	455
	456	# Rebless the object into DBM::Deep::Null.
	457	eval { %{ $self->engine->cache->{ $self->offset } } = (); };
	458	eval { @{ $self->engine->cache->{ $self->offset } } = (); };
	459	bless $self->engine->cache->{ $self->offset }, 'DBM::Deep::Null';
	460	delete $self->engine->cache->{ $self->offset };
	461
	462	my $blist_loc = $self->get_blist_loc;
2c70efe1	463	DBM::Deep::Sector::File->load( $self->engine, $blist_loc )->free if $blist_loc;
f0276afb	464
f0276afb	465	my $class_loc = $self->get_class_offset;
2c70efe1	466	DBM::Deep::Sector::File->load( $self->engine, $class_loc )->free if $class_loc;
f0276afb	467
	468	$self->SUPER::free();
	469	}
	470
	471	sub increment_refcount {
	472	my $self = shift;
	473
	474	my $refcount = $self->get_refcount;
	475
	476	$refcount++;
	477
	478	$self->write_refcount( $refcount );
	479
	480	return $refcount;
	481	}
	482
	483	sub decrement_refcount {
	484	my $self = shift;
	485
	486	my $refcount = $self->get_refcount;
	487
	488	$refcount--;
	489
	490	$self->write_refcount( $refcount );
	491
	492	return $refcount;
	493	}
	494
	495	sub get_refcount {
	496	my $self = shift;
	497
	498	my $e = $self->engine;
	499	return unpack(
	500	$StP{$e->byte_size},
	501	$e->storage->read_at(
	502	$self->offset + $self->base_size + 2 * $e->byte_size, $e->byte_size,
	503	),
	504	);
	505	}
	506
	507	sub write_refcount {
	508	my $self = shift;
	509	my ($num) = @_;
	510
	511	my $e = $self->engine;
	512	$e->storage->print_at(
	513	$self->offset + $self->base_size + 2 * $e->byte_size,
	514	pack( $StP{$e->byte_size}, $num ),
	515	);
	516	}
	517
	518	1;
	519	__END__