1 package DBM::Deep::Engine;
6 use warnings FATAL => 'all';
8 # Never import symbols into our namespace. We are a class, not a library.
15 # * Every method in here assumes that the storage has been appropriately
16 # safeguarded. This can be anything from flock() to some sort of manual
17 # mutex. But, it's the caller's responsability to make sure that this has
20 # Setup file and tag signatures. These should never change.
21 sub SIG_FILE () { 'DPDB' }
22 sub SIG_HEADER () { 'h' }
23 sub SIG_HASH () { 'H' }
24 sub SIG_ARRAY () { 'A' }
25 sub SIG_NULL () { 'N' }
26 sub SIG_DATA () { 'D' }
27 sub SIG_INDEX () { 'I' }
28 sub SIG_BLIST () { 'B' }
29 sub SIG_FREE () { 'F' }
34 # Please refer to the pack() documentation for further information
36 1 => 'C', # Unsigned char value (no order needed as it's just one byte)
37 2 => 'n', # Unsigned short in "network" (big-endian) order
38 4 => 'N', # Unsigned long in "network" (big-endian) order
39 8 => 'Q', # Usigned quad (no order specified, presumably machine-dependent)
42 ################################################################################
48 $args->{storage} = DBM::Deep::File->new( $args )
49 unless exists $args->{storage};
55 hash_size => 16, # In bytes
56 hash_chars => 256, # Number of chars the algorithm uses per byte
58 num_txns => 1, # The HEAD
59 trans_id => 0, # Default to the HEAD
61 data_sector_size => 64, # Size in bytes of each data sector
63 entries => {}, # This is the list of entries for transactions
67 # Never allow byte_size to be set directly.
68 delete $args->{byte_size};
69 if ( defined $args->{pack_size} ) {
70 if ( lc $args->{pack_size} eq 'small' ) {
71 $args->{byte_size} = 2;
73 elsif ( lc $args->{pack_size} eq 'medium' ) {
74 $args->{byte_size} = 4;
76 elsif ( lc $args->{pack_size} eq 'large' ) {
77 $args->{byte_size} = 8;
80 DBM::Deep->_throw_error( "Unknown pack_size value: '$args->{pack_size}'" );
84 # Grab the parameters we want to use
85 foreach my $param ( keys %$self ) {
86 next unless exists $args->{$param};
87 $self->{$param} = $args->{$param};
91 max_buckets => { floor => 16, ceil => 256 },
92 num_txns => { floor => 1, ceil => 255 },
93 data_sector_size => { floor => 32, ceil => 256 },
96 while ( my ($attr, $c) = each %validations ) {
97 if ( !defined $self->{$attr}
98 || !length $self->{$attr}
99 || $self->{$attr} =~ /\D/
100 || $self->{$attr} < $c->{floor}
102 $self->{$attr} = '(undef)' if !defined $self->{$attr};
103 warn "Floor of $attr is $c->{floor}. Setting it to $c->{floor} from '$self->{$attr}'\n";
104 $self->{$attr} = $c->{floor};
106 elsif ( $self->{$attr} > $c->{ceil} ) {
107 warn "Ceiling of $attr is $c->{ceil}. Setting it to $c->{ceil} from '$self->{$attr}'\n";
108 $self->{$attr} = $c->{ceil};
112 if ( !$self->{digest} ) {
114 $self->{digest} = \&Digest::MD5::md5;
120 ################################################################################
124 my ($obj, $key) = @_;
126 # This will be a Reference sector
127 my $sector = $self->_load_sector( $obj->_base_offset )
130 if ( $sector->staleness != $obj->_staleness ) {
134 my $key_md5 = $self->_apply_digest( $key );
136 my $value_sector = $sector->get_data_for({
141 unless ( $value_sector ) {
142 $value_sector = DBM::Deep::Engine::Sector::Null->new({
147 $sector->write_data({
150 value => $value_sector,
154 return $value_sector->data;
161 # This will be a Reference sector
162 my $sector = $self->_load_sector( $obj->_base_offset )
163 or DBM::Deep->_throw_error( "How did get_classname fail (no sector for '$obj')?!" );
165 if ( $sector->staleness != $obj->_staleness ) {
169 return $sector->get_classname;
174 my ($obj, $old_key, $new_key) = @_;
176 # This will be a Reference sector
177 my $sector = $self->_load_sector( $obj->_base_offset )
178 or DBM::Deep->_throw_error( "How did get_classname fail (no sector for '$obj')?!" );
180 if ( $sector->staleness != $obj->_staleness ) {
184 my $old_md5 = $self->_apply_digest( $old_key );
186 my $value_sector = $sector->get_data_for({
191 unless ( $value_sector ) {
192 $value_sector = DBM::Deep::Engine::Sector::Null->new({
197 $sector->write_data({
200 value => $value_sector,
204 if ( $value_sector->isa( 'DBM::Deep::Engine::Sector::Reference' ) ) {
205 $sector->write_data({
207 key_md5 => $self->_apply_digest( $new_key ),
208 value => $value_sector,
210 $value_sector->increment_refcount;
213 $sector->write_data({
215 key_md5 => $self->_apply_digest( $new_key ),
216 value => $value_sector->clone,
223 my ($obj, $key) = @_;
225 # This will be a Reference sector
226 my $sector = $self->_load_sector( $obj->_base_offset )
229 if ( $sector->staleness != $obj->_staleness ) {
233 my $data = $sector->get_data_for({
234 key_md5 => $self->_apply_digest( $key ),
238 # exists() returns 1 or '' for true/false.
239 return $data ? 1 : '';
244 my ($obj, $key) = @_;
246 my $sector = $self->_load_sector( $obj->_base_offset )
249 if ( $sector->staleness != $obj->_staleness ) {
253 return $sector->delete_key({
254 key_md5 => $self->_apply_digest( $key ),
261 my ($obj, $key, $value) = @_;
263 my $r = Scalar::Util::reftype( $value ) || '';
266 last if $r eq 'HASH';
267 last if $r eq 'ARRAY';
269 DBM::Deep->_throw_error(
270 "Storage of references of type '$r' is not supported."
274 # This will be a Reference sector
275 my $sector = $self->_load_sector( $obj->_base_offset )
276 or DBM::Deep->_throw_error( "Cannot write to a deleted spot in DBM::Deep." );
278 if ( $sector->staleness != $obj->_staleness ) {
279 DBM::Deep->_throw_error( "Cannot write to a deleted spot in DBM::Deep." );
283 if ( !defined $value ) {
284 $class = 'DBM::Deep::Engine::Sector::Null';
286 elsif ( $r eq 'ARRAY' || $r eq 'HASH' ) {
288 if ( $r eq 'ARRAY' ) {
289 $tmpvar = tied @$value;
290 } elsif ( $r eq 'HASH' ) {
291 $tmpvar = tied %$value;
295 my $is_dbm_deep = eval { local $SIG{'__DIE__'}; $tmpvar->isa( 'DBM::Deep' ); };
297 unless ( $is_dbm_deep ) {
298 DBM::Deep->_throw_error( "Cannot store something that is tied." );
301 unless ( $tmpvar->_engine->storage == $self->storage ) {
302 DBM::Deep->_throw_error( "Cannot store values across DBM::Deep files. Please use export() instead." );
305 # First, verify if we're storing the same thing to this spot. If we are, then
306 # this should be a no-op. -EJS, 2008-05-19
307 my $loc = $sector->get_data_location_for({
308 key_md5 => $self->_apply_digest( $key ),
312 if ( defined($loc) && $loc == $tmpvar->_base_offset ) {
316 #XXX Can this use $loc?
317 my $value_sector = $self->_load_sector( $tmpvar->_base_offset );
318 $sector->write_data({
320 key_md5 => $self->_apply_digest( $key ),
321 value => $value_sector,
323 $value_sector->increment_refcount;
328 $class = 'DBM::Deep::Engine::Sector::Reference';
329 $type = substr( $r, 0, 1 );
332 if ( tied($value) ) {
333 DBM::Deep->_throw_error( "Cannot store something that is tied." );
335 $class = 'DBM::Deep::Engine::Sector::Scalar';
338 # Create this after loading the reference sector in case something bad happens.
339 # This way, we won't allocate value sector(s) needlessly.
340 my $value_sector = $class->new({
346 $sector->write_data({
348 key_md5 => $self->_apply_digest( $key ),
349 value => $value_sector,
352 # This code is to make sure we write all the values in the $value to the disk
353 # and to make sure all changes to $value after the assignment are reflected
354 # on disk. This may be counter-intuitive at first, but it is correct dwimmery.
355 # NOTE - simply tying $value won't perform a STORE on each value. Hence, the
356 # copy to a temp value.
357 if ( $r eq 'ARRAY' ) {
359 tie @$value, 'DBM::Deep', {
360 base_offset => $value_sector->offset,
361 staleness => $value_sector->staleness,
362 storage => $self->storage,
366 bless $value, 'DBM::Deep::Array' unless Scalar::Util::blessed( $value );
368 elsif ( $r eq 'HASH' ) {
370 tie %$value, 'DBM::Deep', {
371 base_offset => $value_sector->offset,
372 staleness => $value_sector->staleness,
373 storage => $self->storage,
378 bless $value, 'DBM::Deep::Hash' unless Scalar::Util::blessed( $value );
384 # XXX Add staleness here
387 my ($obj, $prev_key) = @_;
389 # XXX Need to add logic about resetting the iterator if any key in the reference has changed
390 unless ( $prev_key ) {
391 $obj->{iterator} = DBM::Deep::Iterator->new({
392 base_offset => $obj->_base_offset,
397 return $obj->{iterator}->get_next_key( $obj );
400 ################################################################################
406 # We're opening the file.
407 unless ( $obj->_base_offset ) {
408 my $bytes_read = $self->_read_file_header;
410 # Creating a new file
411 unless ( $bytes_read ) {
412 $self->_write_file_header;
414 # 1) Create Array/Hash entry
415 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
419 $obj->{base_offset} = $initial_reference->offset;
420 $obj->{staleness} = $initial_reference->staleness;
422 $self->storage->flush;
424 # Reading from an existing file
426 $obj->{base_offset} = $bytes_read;
427 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
429 offset => $obj->_base_offset,
431 unless ( $initial_reference ) {
432 DBM::Deep->_throw_error("Corrupted file, no master index record");
435 unless ($obj->_type eq $initial_reference->type) {
436 DBM::Deep->_throw_error("File type mismatch");
439 $obj->{staleness} = $initial_reference->staleness;
443 $self->storage->set_inode;
452 if ( $self->trans_id ) {
453 DBM::Deep->_throw_error( "Cannot begin_work within an active transaction" );
456 my @slots = $self->read_txn_slots;
458 for my $i ( 0 .. $#slots ) {
462 $self->set_trans_id( $i + 1 );
467 DBM::Deep->_throw_error( "Cannot allocate transaction ID" );
469 $self->write_txn_slots( @slots );
471 if ( !$self->trans_id ) {
472 DBM::Deep->_throw_error( "Cannot begin_work - no available transactions" );
482 if ( !$self->trans_id ) {
483 DBM::Deep->_throw_error( "Cannot rollback without an active transaction" );
486 # Each entry is the file location for a bucket that has a modification for
487 # this transaction. The entries need to be expunged.
488 foreach my $entry (@{ $self->get_entries } ) {
489 # Remove the entry here
490 my $read_loc = $entry
494 + ($self->trans_id - 1) * ( $self->byte_size + $STALE_SIZE );
496 my $data_loc = $self->storage->read_at( $read_loc, $self->byte_size );
497 $data_loc = unpack( $StP{$self->byte_size}, $data_loc );
498 $self->storage->print_at( $read_loc, pack( $StP{$self->byte_size}, 0 ) );
500 if ( $data_loc > 1 ) {
501 $self->_load_sector( $data_loc )->free;
505 $self->clear_entries;
507 my @slots = $self->read_txn_slots;
508 $slots[$self->trans_id-1] = 0;
509 $self->write_txn_slots( @slots );
510 $self->inc_txn_staleness_counter( $self->trans_id );
511 $self->set_trans_id( 0 );
520 if ( !$self->trans_id ) {
521 DBM::Deep->_throw_error( "Cannot commit without an active transaction" );
524 foreach my $entry (@{ $self->get_entries } ) {
525 # Overwrite the entry in head with the entry in trans_id
530 my $head_loc = $self->storage->read_at( $base, $self->byte_size );
531 $head_loc = unpack( $StP{$self->byte_size}, $head_loc );
533 my $spot = $base + $self->byte_size + ($self->trans_id - 1) * ( $self->byte_size + $STALE_SIZE );
534 my $trans_loc = $self->storage->read_at(
535 $spot, $self->byte_size,
538 $self->storage->print_at( $base, $trans_loc );
539 $self->storage->print_at(
541 pack( $StP{$self->byte_size} . ' ' . $StP{$STALE_SIZE}, (0) x 2 ),
544 if ( $head_loc > 1 ) {
545 $self->_load_sector( $head_loc )->free;
549 $self->clear_entries;
551 my @slots = $self->read_txn_slots;
552 $slots[$self->trans_id-1] = 0;
553 $self->write_txn_slots( @slots );
554 $self->inc_txn_staleness_counter( $self->trans_id );
555 $self->set_trans_id( 0 );
562 my $bl = $self->txn_bitfield_len;
563 my $num_bits = $bl * 8;
564 return split '', unpack( 'b'.$num_bits,
565 $self->storage->read_at(
566 $self->trans_loc, $bl,
571 sub write_txn_slots {
573 my $num_bits = $self->txn_bitfield_len * 8;
574 $self->storage->print_at( $self->trans_loc,
575 pack( 'b'.$num_bits, join('', @_) ),
579 sub get_running_txn_ids {
581 my @transactions = $self->read_txn_slots;
582 my @trans_ids = map { $_+1} grep { $transactions[$_] } 0 .. $#transactions;
585 sub get_txn_staleness_counter {
589 # Hardcode staleness of 0 for the HEAD
590 return 0 unless $trans_id;
592 return unpack( $StP{$STALE_SIZE},
593 $self->storage->read_at(
594 $self->trans_loc + $self->txn_bitfield_len + $STALE_SIZE * ($trans_id - 1),
600 sub inc_txn_staleness_counter {
604 # Hardcode staleness of 0 for the HEAD
605 return 0 unless $trans_id;
607 $self->storage->print_at(
608 $self->trans_loc + $self->txn_bitfield_len + $STALE_SIZE * ($trans_id - 1),
609 pack( $StP{$STALE_SIZE}, $self->get_txn_staleness_counter( $trans_id ) + 1 ),
615 return [ keys %{ $self->{entries}{$self->trans_id} ||= {} } ];
620 my ($trans_id, $loc) = @_;
622 $self->{entries}{$trans_id} ||= {};
623 $self->{entries}{$trans_id}{$loc} = undef;
626 # If the buckets are being relocated because of a reindexing, the entries
627 # mechanism needs to be made aware of it.
630 my ($old_loc, $new_loc) = @_;
633 while ( my ($trans_id, $locs) = each %{ $self->{entries} } ) {
634 if ( exists $locs->{$old_loc} ) {
635 delete $locs->{$old_loc};
636 $locs->{$new_loc} = undef;
644 delete $self->{entries}{$self->trans_id};
647 ################################################################################
650 my $header_fixed = length( SIG_FILE ) + 1 + 4 + 4;
651 my $this_file_version = 3;
653 sub _write_file_header {
656 my $nt = $self->num_txns;
657 my $bl = $self->txn_bitfield_len;
659 my $header_var = 1 + 1 + 1 + 1 + $bl + $STALE_SIZE * ($nt - 1) + 3 * $self->byte_size;
661 my $loc = $self->storage->request_space( $header_fixed + $header_var );
663 $self->storage->print_at( $loc,
666 pack('N', $this_file_version), # At this point, we're at 9 bytes
667 pack('N', $header_var), # header size
668 # --- Above is $header_fixed. Below is $header_var
669 pack('C', $self->byte_size),
671 # These shenanigans are to allow a 256 within a C
672 pack('C', $self->max_buckets - 1),
673 pack('C', $self->data_sector_size - 1),
676 pack('C' . $bl, 0 ), # Transaction activeness bitfield
677 pack($StP{$STALE_SIZE}.($nt-1), 0 x ($nt-1) ), # Transaction staleness counters
678 pack($StP{$self->byte_size}, 0), # Start of free chain (blist size)
679 pack($StP{$self->byte_size}, 0), # Start of free chain (data size)
680 pack($StP{$self->byte_size}, 0), # Start of free chain (index size)
683 #XXX Set these less fragilely
684 $self->set_trans_loc( $header_fixed + 4 );
685 $self->set_chains_loc( $header_fixed + 4 + $bl + $STALE_SIZE * ($nt-1) );
690 sub _read_file_header {
693 my $buffer = $self->storage->read_at( 0, $header_fixed );
694 return unless length($buffer);
696 my ($file_signature, $sig_header, $file_version, $size) = unpack(
700 unless ( $file_signature eq SIG_FILE ) {
701 $self->storage->close;
702 DBM::Deep->_throw_error( "Signature not found -- file is not a Deep DB" );
705 unless ( $sig_header eq SIG_HEADER ) {
706 $self->storage->close;
707 DBM::Deep->_throw_error( "Pre-1.00 file version found" );
710 unless ( $file_version == $this_file_version ) {
711 $self->storage->close;
712 DBM::Deep->_throw_error(
713 "Wrong file version found - " . $file_version .
714 " - expected " . $this_file_version
718 my $buffer2 = $self->storage->read_at( undef, $size );
719 my @values = unpack( 'C C C C', $buffer2 );
721 if ( @values != 4 || grep { !defined } @values ) {
722 $self->storage->close;
723 DBM::Deep->_throw_error("Corrupted file - bad header");
726 #XXX Add warnings if values weren't set right
727 @{$self}{qw(byte_size max_buckets data_sector_size num_txns)} = @values;
729 # These shenangians are to allow a 256 within a C
730 $self->{max_buckets} += 1;
731 $self->{data_sector_size} += 1;
733 my $bl = $self->txn_bitfield_len;
735 my $header_var = scalar(@values) + $bl + $STALE_SIZE * ($self->num_txns - 1) + 3 * $self->byte_size;
736 unless ( $size == $header_var ) {
737 $self->storage->close;
738 DBM::Deep->_throw_error( "Unexpected size found ($size <-> $header_var)." );
741 $self->set_trans_loc( $header_fixed + scalar(@values) );
742 $self->set_chains_loc( $header_fixed + scalar(@values) + $bl + $STALE_SIZE * ($self->num_txns - 1) );
744 return length($buffer) + length($buffer2);
752 # Add a catch for offset of 0 or 1
753 return if !$offset || $offset <= 1;
755 my $type = $self->storage->read_at( $offset, 1 );
756 return if $type eq chr(0);
758 if ( $type eq $self->SIG_ARRAY || $type eq $self->SIG_HASH ) {
759 return DBM::Deep::Engine::Sector::Reference->new({
765 # XXX Don't we need key_md5 here?
766 elsif ( $type eq $self->SIG_BLIST ) {
767 return DBM::Deep::Engine::Sector::BucketList->new({
773 elsif ( $type eq $self->SIG_INDEX ) {
774 return DBM::Deep::Engine::Sector::Index->new({
780 elsif ( $type eq $self->SIG_NULL ) {
781 return DBM::Deep::Engine::Sector::Null->new({
787 elsif ( $type eq $self->SIG_DATA ) {
788 return DBM::Deep::Engine::Sector::Scalar->new({
794 # This was deleted from under us, so just return and let the caller figure it out.
795 elsif ( $type eq $self->SIG_FREE ) {
799 DBM::Deep->_throw_error( "'$offset': Don't know what to do with type '$type'" );
804 return $self->{digest}->(@_);
807 sub _add_free_blist_sector { shift->_add_free_sector( 0, @_ ) }
808 sub _add_free_data_sector { shift->_add_free_sector( 1, @_ ) }
809 sub _add_free_index_sector { shift->_add_free_sector( 2, @_ ) }
811 sub _add_free_sector {
813 my ($multiple, $offset, $size) = @_;
815 my $chains_offset = $multiple * $self->byte_size;
817 my $storage = $self->storage;
819 # Increment staleness.
820 # XXX Can this increment+modulo be done by "&= 0x1" ?
821 my $staleness = unpack( $StP{$STALE_SIZE}, $storage->read_at( $offset + SIG_SIZE, $STALE_SIZE ) );
822 $staleness = ($staleness + 1 ) % ( 2 ** ( 8 * $STALE_SIZE ) );
823 $storage->print_at( $offset + SIG_SIZE, pack( $StP{$STALE_SIZE}, $staleness ) );
825 my $old_head = $storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
827 $storage->print_at( $self->chains_loc + $chains_offset,
828 pack( $StP{$self->byte_size}, $offset ),
831 # Record the old head in the new sector after the signature and staleness counter
832 $storage->print_at( $offset + SIG_SIZE + $STALE_SIZE, $old_head );
835 sub _request_blist_sector { shift->_request_sector( 0, @_ ) }
836 sub _request_data_sector { shift->_request_sector( 1, @_ ) }
837 sub _request_index_sector { shift->_request_sector( 2, @_ ) }
839 sub _request_sector {
841 my ($multiple, $size) = @_;
843 my $chains_offset = $multiple * $self->byte_size;
845 my $old_head = $self->storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
846 my $loc = unpack( $StP{$self->byte_size}, $old_head );
848 # We don't have any free sectors of the right size, so allocate a new one.
850 my $offset = $self->storage->request_space( $size );
852 # Zero out the new sector. This also guarantees correct increases
854 $self->storage->print_at( $offset, chr(0) x $size );
859 # Read the new head after the signature and the staleness counter
860 my $new_head = $self->storage->read_at( $loc + SIG_SIZE + $STALE_SIZE, $self->byte_size );
861 $self->storage->print_at( $self->chains_loc + $chains_offset, $new_head );
862 $self->storage->print_at(
863 $loc + SIG_SIZE + $STALE_SIZE,
864 pack( $StP{$self->byte_size}, 0 ),
870 ################################################################################
875 # my $sectors = $self->dirty_sectors;
876 # for my $offset (sort { $a <=> $b } keys %{ $sectors }) {
877 # $self->storage->print_at( $offset, $self->sector_cache->{$offset} );
880 # Why do we need to have the storage flush? Shouldn't autoflush take care of things?
882 $self->storage->flush;
884 # $self->clear_dirty_sectors;
886 # $self->clear_sector_cache;
892 return $self->storage->lock_exclusive( $obj );
898 return $self->storage->lock_shared( $obj );
905 my $rv = $self->storage->unlock( $obj );
912 ################################################################################
914 sub storage { $_[0]{storage} }
915 sub byte_size { $_[0]{byte_size} }
916 sub hash_size { $_[0]{hash_size} }
917 sub hash_chars { $_[0]{hash_chars} }
918 sub num_txns { $_[0]{num_txns} }
919 sub max_buckets { $_[0]{max_buckets} }
920 sub blank_md5 { chr(0) x $_[0]->hash_size }
921 sub data_sector_size { $_[0]{data_sector_size} }
923 # This is a calculated value
924 sub txn_bitfield_len {
926 unless ( exists $self->{txn_bitfield_len} ) {
927 my $temp = ($self->num_txns) / 8;
928 if ( $temp > int( $temp ) ) {
929 $temp = int( $temp ) + 1;
931 $self->{txn_bitfield_len} = $temp;
933 return $self->{txn_bitfield_len};
936 sub trans_id { $_[0]{trans_id} }
937 sub set_trans_id { $_[0]{trans_id} = $_[1] }
939 sub trans_loc { $_[0]{trans_loc} }
940 sub set_trans_loc { $_[0]{trans_loc} = $_[1] }
942 sub chains_loc { $_[0]{chains_loc} }
943 sub set_chains_loc { $_[0]{chains_loc} = $_[1] }
945 sub cache { $_[0]{cache} ||= {} }
946 sub clear_cache { %{$_[0]->cache} = () }
952 my $spot = $self->_read_file_header();
961 'D' => $self->data_sector_size,
962 'B' => DBM::Deep::Engine::Sector::BucketList->new({engine=>$self,offset=>1})->size,
963 'I' => DBM::Deep::Engine::Sector::Index->new({engine=>$self,offset=>1})->size,
969 $return .= "NumTxns: " . $self->num_txns . $/;
971 # Read the free sector chains
973 foreach my $multiple ( 0 .. 2 ) {
974 $return .= "Chains($types{$multiple}):";
975 my $old_loc = $self->chains_loc + $multiple * $self->byte_size;
978 $StP{$self->byte_size},
979 $self->storage->read_at( $old_loc, $self->byte_size ),
982 # We're now out of free sectors of this kind.
987 $sectors{ $types{$multiple} }{ $loc } = undef;
988 $old_loc = $loc + SIG_SIZE + $STALE_SIZE;
995 while ( $spot < $self->storage->{end} ) {
996 # Read each sector in order.
997 my $sector = $self->_load_sector( $spot );
999 # Find it in the free-sectors that were found already
1000 foreach my $type ( keys %sectors ) {
1001 if ( exists $sectors{$type}{$spot} ) {
1002 my $size = $sizes{$type};
1003 $return .= sprintf "%08d: %s %04d\n", $spot, 'F' . $type, $size;
1009 die "********\n$return\nDidn't find free sector for $spot in chains\n********\n";
1012 $return .= sprintf "%08d: %s %04d", $spot, $sector->type, $sector->size;
1013 if ( $sector->type eq 'D' ) {
1014 $return .= ' ' . $sector->data;
1016 elsif ( $sector->type eq 'A' || $sector->type eq 'H' ) {
1017 $return .= ' REF: ' . $sector->get_refcount;
1019 elsif ( $sector->type eq 'B' ) {
1020 foreach my $bucket ( $sector->chopped_up ) {
1022 $return .= sprintf "%08d", unpack($StP{$self->byte_size},
1023 substr( $bucket->[-1], $self->hash_size, $self->byte_size),
1025 my $l = unpack( $StP{$self->byte_size},
1026 substr( $bucket->[-1],
1027 $self->hash_size + $self->byte_size,
1031 $return .= sprintf " %08d", $l;
1032 foreach my $txn ( 0 .. $self->num_txns - 2 ) {
1033 my $l = unpack( $StP{$self->byte_size},
1034 substr( $bucket->[-1],
1035 $self->hash_size + 2 * $self->byte_size + $txn * ($self->byte_size + $STALE_SIZE),
1039 $return .= sprintf " %08d", $l;
1045 $spot += $sector->size;
1052 ################################################################################
1054 package DBM::Deep::Iterator;
1062 engine => $args->{engine},
1063 base_offset => $args->{base_offset},
1066 Scalar::Util::weaken( $self->{engine} );
1071 sub reset { $_[0]{breadcrumbs} = [] }
1073 sub get_sector_iterator {
1077 my $sector = $self->{engine}->_load_sector( $loc )
1080 if ( $sector->isa( 'DBM::Deep::Engine::Sector::Index' ) ) {
1081 return DBM::Deep::Iterator::Index->new({
1086 elsif ( $sector->isa( 'DBM::Deep::Engine::Sector::BucketList' ) ) {
1087 return DBM::Deep::Iterator::BucketList->new({
1093 DBM::Deep->_throw_error( "get_sector_iterator(): Why did $loc make a $sector?" );
1100 my $crumbs = $self->{breadcrumbs};
1101 my $e = $self->{engine};
1103 unless ( @$crumbs ) {
1104 # This will be a Reference sector
1105 my $sector = $e->_load_sector( $self->{base_offset} )
1106 # If no sector is found, thist must have been deleted from under us.
1109 if ( $sector->staleness != $obj->_staleness ) {
1113 my $loc = $sector->get_blist_loc
1116 push @$crumbs, $self->get_sector_iterator( $loc );
1121 unless ( @$crumbs ) {
1126 my $iterator = $crumbs->[-1];
1128 # This level is done.
1129 if ( $iterator->at_end ) {
1134 if ( $iterator->isa( 'DBM::Deep::Iterator::Index' ) ) {
1135 # If we don't have any more, it will be caught at the
1137 if ( my $next = $iterator->get_next_iterator ) {
1138 push @$crumbs, $next;
1143 unless ( $iterator->isa( 'DBM::Deep::Iterator::BucketList' ) ) {
1144 DBM::Deep->_throw_error(
1145 "Should have a bucketlist iterator here - instead have $iterator"
1149 # At this point, we have a BucketList iterator
1150 my $key = $iterator->get_next_key;
1151 if ( defined $key ) {
1154 #XXX else { $iterator->set_to_end() } ?
1156 # We hit the end of the bucketlist iterator, so redo
1160 DBM::Deep->_throw_error( "get_next_key(): How did we get here?" );
1163 package DBM::Deep::Iterator::Index;
1166 my $self = bless $_[1] => $_[0];
1167 $self->{curr_index} = 0;
1173 return $self->{curr_index} >= $self->{iterator}{engine}->hash_chars;
1176 sub get_next_iterator {
1181 return if $self->at_end;
1182 $loc = $self->{sector}->get_entry( $self->{curr_index}++ );
1185 return $self->{iterator}->get_sector_iterator( $loc );
1188 package DBM::Deep::Iterator::BucketList;
1191 my $self = bless $_[1] => $_[0];
1192 $self->{curr_index} = 0;
1198 return $self->{curr_index} >= $self->{iterator}{engine}->max_buckets;
1204 return if $self->at_end;
1206 my $idx = $self->{curr_index}++;
1208 my $data_loc = $self->{sector}->get_data_location_for({
1213 #XXX Do we want to add corruption checks here?
1214 return $self->{sector}->get_key_for( $idx )->data;
1217 package DBM::Deep::Engine::Sector;
1220 my $self = bless $_[1], $_[0];
1221 Scalar::Util::weaken( $self->{engine} );
1227 #sub clone { DBM::Deep->_throw_error( "Must be implemented in the child class" ); }
1229 sub engine { $_[0]{engine} }
1230 sub offset { $_[0]{offset} }
1231 sub type { $_[0]{type} }
1235 return $self->engine->SIG_SIZE + $STALE_SIZE;
1241 my $e = $self->engine;
1243 $e->storage->print_at( $self->offset, $e->SIG_FREE );
1244 # Skip staleness counter
1245 $e->storage->print_at( $self->offset + $self->base_size,
1246 chr(0) x ($self->size - $self->base_size),
1249 my $free_meth = $self->free_meth;
1250 $e->$free_meth( $self->offset, $self->size );
1255 package DBM::Deep::Engine::Sector::Data;
1257 our @ISA = qw( DBM::Deep::Engine::Sector );
1260 sub size { $_[0]{engine}->data_sector_size }
1261 sub free_meth { return '_add_free_data_sector' }
1265 return ref($self)->new({
1266 engine => $self->engine,
1267 type => $self->type,
1268 data => $self->data,
1272 package DBM::Deep::Engine::Sector::Scalar;
1274 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1279 my $chain_loc = $self->chain_loc;
1281 $self->SUPER::free();
1284 $self->engine->_load_sector( $chain_loc )->free;
1290 sub type { $_[0]{engine}->SIG_DATA }
1294 my $engine = $self->engine;
1296 unless ( $self->offset ) {
1297 my $data_section = $self->size - $self->base_size - $engine->byte_size - 1;
1299 $self->{offset} = $engine->_request_data_sector( $self->size );
1301 my $data = delete $self->{data};
1302 my $dlen = length $data;
1304 my $curr_offset = $self->offset;
1305 while ( $continue ) {
1307 my $next_offset = 0;
1309 my ($leftover, $this_len, $chunk);
1310 if ( $dlen > $data_section ) {
1312 $this_len = $data_section;
1313 $chunk = substr( $data, 0, $this_len );
1315 $dlen -= $data_section;
1316 $next_offset = $engine->_request_data_sector( $self->size );
1317 $data = substr( $data, $this_len );
1320 $leftover = $data_section - $dlen;
1327 $engine->storage->print_at( $curr_offset, $self->type ); # Sector type
1329 $engine->storage->print_at( $curr_offset + $self->base_size,
1330 pack( $StP{$engine->byte_size}, $next_offset ), # Chain loc
1331 pack( $StP{1}, $this_len ), # Data length
1332 $chunk, # Data to be stored in this sector
1333 chr(0) x $leftover, # Zero-fill the rest
1336 $curr_offset = $next_offset;
1346 my $buffer = $self->engine->storage->read_at(
1347 $self->offset + $self->base_size + $self->engine->byte_size, 1
1350 return unpack( $StP{1}, $buffer );
1356 $StP{$self->engine->byte_size},
1357 $self->engine->storage->read_at(
1358 $self->offset + $self->base_size,
1359 $self->engine->byte_size,
1371 my $chain_loc = $self->chain_loc;
1373 $data .= $self->engine->storage->read_at(
1374 $self->offset + $self->base_size + $self->engine->byte_size + 1, $self->data_length,
1377 last unless $chain_loc;
1379 $self = $self->engine->_load_sector( $chain_loc );
1385 package DBM::Deep::Engine::Sector::Null;
1387 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1389 sub type { $_[0]{engine}->SIG_NULL }
1390 sub data_length { 0 }
1396 my $engine = $self->engine;
1398 unless ( $self->offset ) {
1399 my $leftover = $self->size - $self->base_size - 1 * $engine->byte_size - 1;
1401 $self->{offset} = $engine->_request_data_sector( $self->size );
1402 $engine->storage->print_at( $self->offset, $self->type ); # Sector type
1403 # Skip staleness counter
1404 $engine->storage->print_at( $self->offset + $self->base_size,
1405 pack( $StP{$engine->byte_size}, 0 ), # Chain loc
1406 pack( $StP{1}, $self->data_length ), # Data length
1407 chr(0) x $leftover, # Zero-fill the rest
1414 package DBM::Deep::Engine::Sector::Reference;
1416 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1421 my $e = $self->engine;
1423 unless ( $self->offset ) {
1424 my $classname = Scalar::Util::blessed( delete $self->{data} );
1425 my $leftover = $self->size - $self->base_size - 3 * $e->byte_size;
1427 my $class_offset = 0;
1428 if ( defined $classname ) {
1429 my $class_sector = DBM::Deep::Engine::Sector::Scalar->new({
1433 $class_offset = $class_sector->offset;
1436 $self->{offset} = $e->_request_data_sector( $self->size );
1437 $e->storage->print_at( $self->offset, $self->type ); # Sector type
1438 # Skip staleness counter
1439 $e->storage->print_at( $self->offset + $self->base_size,
1440 pack( $StP{$e->byte_size}, 0 ), # Index/BList loc
1441 pack( $StP{$e->byte_size}, $class_offset ), # Classname loc
1442 pack( $StP{$e->byte_size}, 1 ), # Initial refcount
1443 chr(0) x $leftover, # Zero-fill the rest
1447 $self->{type} = $e->storage->read_at( $self->offset, 1 );
1450 $self->{staleness} = unpack(
1452 $e->storage->read_at( $self->offset + $e->SIG_SIZE, $STALE_SIZE ),
1458 sub staleness { $_[0]{staleness} }
1460 sub get_data_location_for {
1464 # Assume that the head is not allowed unless otherwise specified.
1465 $args->{allow_head} = 0 unless exists $args->{allow_head};
1467 # Assume we don't create a new blist location unless otherwise specified.
1468 $args->{create} = 0 unless exists $args->{create};
1470 my $blist = $self->get_bucket_list({
1471 key_md5 => $args->{key_md5},
1472 key => $args->{key},
1473 create => $args->{create},
1475 return unless $blist && $blist->{found};
1477 # At this point, $blist knows where the md5 is. What it -doesn't- know yet
1478 # is whether or not this transaction has this key. That's part of the next
1480 my $location = $blist->get_data_location_for({
1481 allow_head => $args->{allow_head},
1491 my $location = $self->get_data_location_for( $args )
1494 return $self->engine->_load_sector( $location );
1501 my $blist = $self->get_bucket_list({
1502 key_md5 => $args->{key_md5},
1503 key => $args->{key},
1505 }) or DBM::Deep->_throw_error( "How did write_data fail (no blist)?!" );
1507 # Handle any transactional bookkeeping.
1508 if ( $self->engine->trans_id ) {
1509 if ( ! $blist->has_md5 ) {
1510 $blist->mark_deleted({
1516 my @trans_ids = $self->engine->get_running_txn_ids;
1517 if ( $blist->has_md5 ) {
1519 my $old_value = $blist->get_data_for;
1520 foreach my $other_trans_id ( @trans_ids ) {
1521 next if $blist->get_data_location_for({
1522 trans_id => $other_trans_id,
1526 trans_id => $other_trans_id,
1527 key => $args->{key},
1528 key_md5 => $args->{key_md5},
1529 value => $old_value->clone,
1536 foreach my $other_trans_id ( @trans_ids ) {
1537 #XXX This doesn't seem to possible to ever happen . . .
1538 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1539 $blist->mark_deleted({
1540 trans_id => $other_trans_id,
1547 #XXX Is this safe to do transactionally?
1548 # Free the place we're about to write to.
1549 if ( $blist->get_data_location_for({ allow_head => 0 }) ) {
1550 $blist->get_data_for({ allow_head => 0 })->free;
1554 key => $args->{key},
1555 key_md5 => $args->{key_md5},
1556 value => $args->{value},
1564 # XXX What should happen if this fails?
1565 my $blist = $self->get_bucket_list({
1566 key_md5 => $args->{key_md5},
1567 }) or DBM::Deep->_throw_error( "How did delete_key fail (no blist)?!" );
1569 # Save the location so that we can free the data
1570 my $location = $blist->get_data_location_for({
1573 my $old_value = $location && $self->engine->_load_sector( $location );
1575 my @trans_ids = $self->engine->get_running_txn_ids;
1577 # If we're the HEAD and there are running txns, then we need to clone this value to the other
1578 # transactions to preserve Isolation.
1579 if ( $self->engine->trans_id == 0 ) {
1581 foreach my $other_trans_id ( @trans_ids ) {
1582 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1584 trans_id => $other_trans_id,
1585 key => $args->{key},
1586 key_md5 => $args->{key_md5},
1587 value => $old_value->clone,
1595 $blist->mark_deleted( $args );
1598 $data = $old_value->data({ export => 1 });
1603 $data = $blist->delete_md5( $args );
1612 my $e = $self->engine;
1613 my $blist_loc = $e->storage->read_at( $self->offset + $self->base_size, $e->byte_size );
1614 return unpack( $StP{$e->byte_size}, $blist_loc );
1617 sub get_bucket_list {
1622 # XXX Add in check here for recycling?
1624 my $engine = $self->engine;
1626 my $blist_loc = $self->get_blist_loc;
1628 # There's no index or blist yet
1629 unless ( $blist_loc ) {
1630 return unless $args->{create};
1632 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1634 key_md5 => $args->{key_md5},
1637 $engine->storage->print_at( $self->offset + $self->base_size,
1638 pack( $StP{$engine->byte_size}, $blist->offset ),
1644 my $sector = $engine->_load_sector( $blist_loc )
1645 or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
1647 my $last_sector = undef;
1648 while ( $sector->isa( 'DBM::Deep::Engine::Sector::Index' ) ) {
1649 $blist_loc = $sector->get_entry( ord( substr( $args->{key_md5}, $i++, 1 ) ) );
1650 $last_sector = $sector;
1652 $sector = $engine->_load_sector( $blist_loc )
1653 or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
1661 # This means we went through the Index sector(s) and found an empty slot
1662 unless ( $sector ) {
1663 return unless $args->{create};
1665 DBM::Deep->_throw_error( "No last_sector when attempting to build a new entry" )
1666 unless $last_sector;
1668 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1670 key_md5 => $args->{key_md5},
1673 $last_sector->set_entry( ord( substr( $args->{key_md5}, $i - 1, 1 ) ) => $blist->offset );
1678 $sector->find_md5( $args->{key_md5} );
1680 # See whether or not we need to reindex the bucketlist
1681 # Yes, the double-braces are there for a reason. if() doesn't create a redo-able block,
1682 # so we have to create a bare block within the if() for redo-purposes. Patch and idea
1683 # submitted by sprout@cpan.org. -RobK, 2008-01-09
1684 if ( !$sector->has_md5 && $args->{create} && $sector->{idx} == -1 ) {{
1687 my $new_index = DBM::Deep::Engine::Sector::Index->new({
1692 #XXX q.v. the comments for this function.
1693 foreach my $entry ( $sector->chopped_up ) {
1694 my ($spot, $md5) = @{$entry};
1695 my $idx = ord( substr( $md5, $i, 1 ) );
1697 # XXX This is inefficient
1698 my $blist = $blist_cache{$idx}
1699 ||= DBM::Deep::Engine::Sector::BucketList->new({
1703 $new_index->set_entry( $idx => $blist->offset );
1705 my $new_spot = $blist->write_at_next_open( $md5 );
1706 $engine->reindex_entry( $spot => $new_spot );
1709 # Handle the new item separately.
1711 my $idx = ord( substr( $args->{key_md5}, $i, 1 ) );
1713 # If all the previous blist's items have been thrown into one
1714 # blist and the new item belongs in there too, we need
1716 if ( keys %blist_cache == 1 and each %blist_cache == $idx ) {
1719 my $blist = $blist_cache{$idx}
1720 ||= DBM::Deep::Engine::Sector::BucketList->new({
1724 $new_index->set_entry( $idx => $blist->offset );
1727 $blist->find_md5( $args->{key_md5} );
1729 key => $args->{key},
1730 key_md5 => $args->{key_md5},
1731 value => DBM::Deep::Engine::Sector::Null->new({
1737 # my $blist = $blist_cache{$idx}
1738 # ||= DBM::Deep::Engine::Sector::BucketList->new({
1739 # engine => $engine,
1742 # $new_index->set_entry( $idx => $blist->offset );
1744 # #XXX THIS IS HACKY!
1745 # $blist->find_md5( $args->{key_md5} );
1746 # $blist->write_md5({
1747 # key => $args->{key},
1748 # key_md5 => $args->{key_md5},
1749 # value => DBM::Deep::Engine::Sector::Null->new({
1750 # engine => $engine,
1756 if ( $last_sector ) {
1757 $last_sector->set_entry(
1758 ord( substr( $args->{key_md5}, $i - 1, 1 ) ),
1762 $engine->storage->print_at( $self->offset + $self->base_size,
1763 pack( $StP{$engine->byte_size}, $new_index->offset ),
1771 (undef, $sector) = %blist_cache;
1772 $last_sector = $new_index;
1776 $sector = $blist_cache{ ord( substr( $args->{key_md5}, $i, 1 ) ) };
1777 $sector->find_md5( $args->{key_md5} );
1783 sub get_class_offset {
1786 my $e = $self->engine;
1788 $StP{$e->byte_size},
1789 $e->storage->read_at(
1790 $self->offset + $self->base_size + 1 * $e->byte_size, $e->byte_size,
1798 my $class_offset = $self->get_class_offset;
1800 return unless $class_offset;
1802 return $self->engine->_load_sector( $class_offset )->data;
1811 unless ( $obj = $self->engine->cache->{ $self->offset } ) {
1812 $obj = DBM::Deep->new({
1813 type => $self->type,
1814 base_offset => $self->offset,
1815 staleness => $self->staleness,
1816 storage => $self->engine->storage,
1817 engine => $self->engine,
1820 if ( $self->engine->storage->{autobless} ) {
1821 my $classname = $self->get_classname;
1822 if ( defined $classname ) {
1823 bless $obj, $classname;
1827 $self->engine->cache->{$self->offset} = $obj;
1830 # We're not exporting, so just return.
1831 unless ( $args->{export} ) {
1835 # We shouldn't export if this is still referred to.
1836 if ( $self->get_refcount > 1 ) {
1840 return $obj->export;
1846 # We're not ready to be removed yet.
1847 if ( $self->decrement_refcount > 0 ) {
1851 # Rebless the object into DBM::Deep::Null.
1852 eval { %{ $self->engine->cache->{ $self->offset } } = (); };
1853 eval { @{ $self->engine->cache->{ $self->offset } } = (); };
1854 bless $self->engine->cache->{ $self->offset }, 'DBM::Deep::Null';
1855 delete $self->engine->cache->{ $self->offset };
1857 my $blist_loc = $self->get_blist_loc;
1858 $self->engine->_load_sector( $blist_loc )->free if $blist_loc;
1860 my $class_loc = $self->get_class_offset;
1861 $self->engine->_load_sector( $class_loc )->free if $class_loc;
1863 $self->SUPER::free();
1866 sub increment_refcount {
1869 my $refcount = $self->get_refcount;
1873 $self->write_refcount( $refcount );
1878 sub decrement_refcount {
1881 my $refcount = $self->get_refcount;
1885 $self->write_refcount( $refcount );
1893 my $e = $self->engine;
1895 $StP{$e->byte_size},
1896 $e->storage->read_at(
1897 $self->offset + $self->base_size + 2 * $e->byte_size, $e->byte_size,
1902 sub write_refcount {
1906 my $e = $self->engine;
1907 $e->storage->print_at(
1908 $self->offset + $self->base_size + 2 * $e->byte_size,
1909 pack( $StP{$e->byte_size}, $num ),
1913 package DBM::Deep::Engine::Sector::BucketList;
1915 our @ISA = qw( DBM::Deep::Engine::Sector );
1920 my $engine = $self->engine;
1922 unless ( $self->offset ) {
1923 my $leftover = $self->size - $self->base_size;
1925 $self->{offset} = $engine->_request_blist_sector( $self->size );
1926 $engine->storage->print_at( $self->offset, $engine->SIG_BLIST ); # Sector type
1927 # Skip staleness counter
1928 $engine->storage->print_at( $self->offset + $self->base_size,
1929 chr(0) x $leftover, # Zero-fill the data
1933 if ( $self->{key_md5} ) {
1942 $self->engine->storage->print_at( $self->offset + $self->base_size,
1943 chr(0) x ($self->size - $self->base_size), # Zero-fill the data
1949 unless ( $self->{size} ) {
1950 my $e = $self->engine;
1951 # Base + numbuckets * bucketsize
1952 $self->{size} = $self->base_size + $e->max_buckets * $self->bucket_size;
1954 return $self->{size};
1957 sub free_meth { return '_add_free_blist_sector' }
1962 my $e = $self->engine;
1963 foreach my $bucket ( $self->chopped_up ) {
1964 my $rest = $bucket->[-1];
1966 # Delete the keysector
1967 my $l = unpack( $StP{$e->byte_size}, substr( $rest, $e->hash_size, $e->byte_size ) );
1968 my $s = $e->_load_sector( $l ); $s->free if $s;
1970 # Delete the HEAD sector
1971 $l = unpack( $StP{$e->byte_size},
1973 $e->hash_size + $e->byte_size,
1977 $s = $e->_load_sector( $l ); $s->free if $s;
1979 foreach my $txn ( 0 .. $e->num_txns - 2 ) {
1980 my $l = unpack( $StP{$e->byte_size},
1982 $e->hash_size + 2 * $e->byte_size + $txn * ($e->byte_size + $STALE_SIZE),
1986 my $s = $e->_load_sector( $l ); $s->free if $s;
1990 $self->SUPER::free();
1995 unless ( $self->{bucket_size} ) {
1996 my $e = $self->engine;
1997 # Key + head (location) + transactions (location + staleness-counter)
1998 my $location_size = $e->byte_size + $e->byte_size + ($e->num_txns - 1) * ($e->byte_size + $STALE_SIZE);
1999 $self->{bucket_size} = $e->hash_size + $location_size;
2001 return $self->{bucket_size};
2004 # XXX This is such a poor hack. I need to rethink this code.
2008 my $e = $self->engine;
2011 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
2012 my $spot = $self->offset + $self->base_size + $idx * $self->bucket_size;
2013 my $md5 = $e->storage->read_at( $spot, $e->hash_size );
2015 #XXX If we're chopping, why would we ever have the blank_md5?
2016 last if $md5 eq $e->blank_md5;
2018 my $rest = $e->storage->read_at( undef, $self->bucket_size - $e->hash_size );
2019 push @buckets, [ $spot, $md5 . $rest ];
2025 sub write_at_next_open {
2029 #XXX This is such a hack!
2030 $self->{_next_open} = 0 unless exists $self->{_next_open};
2032 my $spot = $self->offset + $self->base_size + $self->{_next_open}++ * $self->bucket_size;
2033 $self->engine->storage->print_at( $spot, $entry );
2040 unless ( exists $self->{found} ) {
2043 return $self->{found};
2049 $self->{found} = undef;
2053 $self->{key_md5} = shift;
2056 # If we don't have an MD5, then what are we supposed to do?
2057 unless ( exists $self->{key_md5} ) {
2058 DBM::Deep->_throw_error( "Cannot find_md5 without a key_md5 set" );
2061 my $e = $self->engine;
2062 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
2063 my $potential = $e->storage->read_at(
2064 $self->offset + $self->base_size + $idx * $self->bucket_size, $e->hash_size,
2067 if ( $potential eq $e->blank_md5 ) {
2068 $self->{idx} = $idx;
2072 if ( $potential eq $self->{key_md5} ) {
2074 $self->{idx} = $idx;
2086 DBM::Deep->_throw_error( "write_md5: no key" ) unless exists $args->{key};
2087 DBM::Deep->_throw_error( "write_md5: no key_md5" ) unless exists $args->{key_md5};
2088 DBM::Deep->_throw_error( "write_md5: no value" ) unless exists $args->{value};
2090 my $engine = $self->engine;
2092 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
2094 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
2095 $engine->add_entry( $args->{trans_id}, $spot );
2097 unless ($self->{found}) {
2098 my $key_sector = DBM::Deep::Engine::Sector::Scalar->new({
2100 data => $args->{key},
2103 $engine->storage->print_at( $spot,
2105 pack( $StP{$engine->byte_size}, $key_sector->offset ),
2110 + $engine->hash_size
2111 + $engine->byte_size;
2113 if ( $args->{trans_id} ) {
2114 $loc += $engine->byte_size + ($args->{trans_id} - 1) * ( $engine->byte_size + $STALE_SIZE );
2116 $engine->storage->print_at( $loc,
2117 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
2118 pack( $StP{$STALE_SIZE}, $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
2122 $engine->storage->print_at( $loc,
2123 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
2133 my $engine = $self->engine;
2135 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
2137 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
2138 $engine->add_entry( $args->{trans_id}, $spot );
2141 + $engine->hash_size
2142 + $engine->byte_size;
2144 if ( $args->{trans_id} ) {
2145 $loc += $engine->byte_size + ($args->{trans_id} - 1) * ( $engine->byte_size + $STALE_SIZE );
2147 $engine->storage->print_at( $loc,
2148 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
2149 pack( $StP{$STALE_SIZE}, $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
2153 $engine->storage->print_at( $loc,
2154 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
2164 my $engine = $self->engine;
2165 return undef unless $self->{found};
2167 # Save the location so that we can free the data
2168 my $location = $self->get_data_location_for({
2171 my $key_sector = $self->get_key_for;
2173 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
2174 $engine->storage->print_at( $spot,
2175 $engine->storage->read_at(
2176 $spot + $self->bucket_size,
2177 $self->bucket_size * ( $engine->max_buckets - $self->{idx} - 1 ),
2179 chr(0) x $self->bucket_size,
2184 my $data_sector = $self->engine->_load_sector( $location );
2185 my $data = $data_sector->data({ export => 1 });
2191 sub get_data_location_for {
2196 $args->{allow_head} = 0 unless exists $args->{allow_head};
2197 $args->{trans_id} = $self->engine->trans_id unless exists $args->{trans_id};
2198 $args->{idx} = $self->{idx} unless exists $args->{idx};
2200 my $e = $self->engine;
2202 my $spot = $self->offset + $self->base_size
2203 + $args->{idx} * $self->bucket_size
2207 if ( $args->{trans_id} ) {
2208 $spot += $e->byte_size + ($args->{trans_id} - 1) * ( $e->byte_size + $STALE_SIZE );
2211 my $buffer = $e->storage->read_at(
2213 $e->byte_size + $STALE_SIZE,
2215 my ($loc, $staleness) = unpack( $StP{$e->byte_size} . ' ' . $StP{$STALE_SIZE}, $buffer );
2217 # XXX Merge the two if-clauses below
2218 if ( $args->{trans_id} ) {
2219 # We have found an entry that is old, so get rid of it
2220 if ( $staleness != (my $s = $e->get_txn_staleness_counter( $args->{trans_id} ) ) ) {
2221 $e->storage->print_at(
2223 pack( $StP{$e->byte_size} . ' ' . $StP{$STALE_SIZE}, (0) x 2 ),
2229 # If we're in a transaction and we never wrote to this location, try the
2231 if ( $args->{trans_id} && !$loc && $args->{allow_head} ) {
2232 return $self->get_data_location_for({
2235 idx => $args->{idx},
2239 return $loc <= 1 ? 0 : $loc;
2247 return unless $self->{found};
2248 my $location = $self->get_data_location_for({
2249 allow_head => $args->{allow_head},
2251 return $self->engine->_load_sector( $location );
2257 $idx = $self->{idx} unless defined $idx;
2259 if ( $idx >= $self->engine->max_buckets ) {
2260 DBM::Deep->_throw_error( "get_key_for(): Attempting to retrieve $idx" );
2263 my $location = $self->engine->storage->read_at(
2264 $self->offset + $self->base_size + $idx * $self->bucket_size + $self->engine->hash_size,
2265 $self->engine->byte_size,
2267 $location = unpack( $StP{$self->engine->byte_size}, $location );
2268 DBM::Deep->_throw_error( "get_key_for: No location?" ) unless $location;
2270 return $self->engine->_load_sector( $location );
2273 package DBM::Deep::Engine::Sector::Index;
2275 our @ISA = qw( DBM::Deep::Engine::Sector );
2280 my $engine = $self->engine;
2282 unless ( $self->offset ) {
2283 my $leftover = $self->size - $self->base_size;
2285 $self->{offset} = $engine->_request_index_sector( $self->size );
2286 $engine->storage->print_at( $self->offset, $engine->SIG_INDEX ); # Sector type
2287 # Skip staleness counter
2288 $engine->storage->print_at( $self->offset + $self->base_size,
2289 chr(0) x $leftover, # Zero-fill the rest
2299 unless ( $self->{size} ) {
2300 my $e = $self->engine;
2301 $self->{size} = $self->base_size + $e->byte_size * $e->hash_chars;
2303 return $self->{size};
2306 sub free_meth { return '_add_free_index_sector' }
2310 my $e = $self->engine;
2312 for my $i ( 0 .. $e->hash_chars - 1 ) {
2313 my $l = $self->get_entry( $i ) or next;
2314 $e->_load_sector( $l )->free;
2317 $self->SUPER::free();
2323 return $self->offset + $self->base_size + $idx * $self->engine->byte_size;
2330 my $e = $self->engine;
2332 DBM::Deep->_throw_error( "get_entry: Out of range ($idx)" )
2333 if $idx < 0 || $idx >= $e->hash_chars;
2336 $StP{$e->byte_size},
2337 $e->storage->read_at( $self->_loc_for( $idx ), $e->byte_size ),
2343 my ($idx, $loc) = @_;
2345 my $e = $self->engine;
2347 DBM::Deep->_throw_error( "set_entry: Out of range ($idx)" )
2348 if $idx < 0 || $idx >= $e->hash_chars;
2350 $self->engine->storage->print_at(
2351 $self->_loc_for( $idx ),
2352 pack( $StP{$e->byte_size}, $loc ),
2356 # This was copied from MARCEL's Class::Null. However, I couldn't use it because
2357 # I need an undef value, not an implementation of the Null Class pattern.
2358 package DBM::Deep::Null;
2361 'bool' => sub { undef },
2362 '""' => sub { undef },
2363 '0+' => sub { undef },
2365 nomethod => 'AUTOLOAD';
2367 sub AUTOLOAD { return; }