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;
450 if ( $self->trans_id ) {
451 DBM::Deep->_throw_error( "Cannot begin_work within an active transaction" );
454 my @slots = $self->read_txn_slots;
456 for my $i ( 0 .. $#slots ) {
460 $self->set_trans_id( $i + 1 );
465 DBM::Deep->_throw_error( "Cannot allocate transaction ID" );
467 $self->write_txn_slots( @slots );
469 if ( !$self->trans_id ) {
470 DBM::Deep->_throw_error( "Cannot begin_work - no available transactions" );
480 if ( !$self->trans_id ) {
481 DBM::Deep->_throw_error( "Cannot rollback without an active transaction" );
484 # Each entry is the file location for a bucket that has a modification for
485 # this transaction. The entries need to be expunged.
486 foreach my $entry (@{ $self->get_entries } ) {
487 # Remove the entry here
488 my $read_loc = $entry
492 + ($self->trans_id - 1) * ( $self->byte_size + $STALE_SIZE );
494 my $data_loc = $self->storage->read_at( $read_loc, $self->byte_size );
495 $data_loc = unpack( $StP{$self->byte_size}, $data_loc );
496 $self->storage->print_at( $read_loc, pack( $StP{$self->byte_size}, 0 ) );
498 if ( $data_loc > 1 ) {
499 $self->_load_sector( $data_loc )->free;
503 $self->clear_entries;
505 my @slots = $self->read_txn_slots;
506 $slots[$self->trans_id-1] = 0;
507 $self->write_txn_slots( @slots );
508 $self->inc_txn_staleness_counter( $self->trans_id );
509 $self->set_trans_id( 0 );
518 if ( !$self->trans_id ) {
519 DBM::Deep->_throw_error( "Cannot commit without an active transaction" );
522 foreach my $entry (@{ $self->get_entries } ) {
523 # Overwrite the entry in head with the entry in trans_id
528 my $head_loc = $self->storage->read_at( $base, $self->byte_size );
529 $head_loc = unpack( $StP{$self->byte_size}, $head_loc );
531 my $spot = $base + $self->byte_size + ($self->trans_id - 1) * ( $self->byte_size + $STALE_SIZE );
532 my $trans_loc = $self->storage->read_at(
533 $spot, $self->byte_size,
536 $self->storage->print_at( $base, $trans_loc );
537 $self->storage->print_at(
539 pack( $StP{$self->byte_size} . ' ' . $StP{$STALE_SIZE}, (0) x 2 ),
542 if ( $head_loc > 1 ) {
543 $self->_load_sector( $head_loc )->free;
547 $self->clear_entries;
549 my @slots = $self->read_txn_slots;
550 $slots[$self->trans_id-1] = 0;
551 $self->write_txn_slots( @slots );
552 $self->inc_txn_staleness_counter( $self->trans_id );
553 $self->set_trans_id( 0 );
560 my $bl = $self->txn_bitfield_len;
561 my $num_bits = $bl * 8;
562 return split '', unpack( 'b'.$num_bits,
563 $self->storage->read_at(
564 $self->trans_loc, $bl,
569 sub write_txn_slots {
571 my $num_bits = $self->txn_bitfield_len * 8;
572 $self->storage->print_at( $self->trans_loc,
573 pack( 'b'.$num_bits, join('', @_) ),
577 sub get_running_txn_ids {
579 my @transactions = $self->read_txn_slots;
580 my @trans_ids = map { $_+1} grep { $transactions[$_] } 0 .. $#transactions;
583 sub get_txn_staleness_counter {
587 # Hardcode staleness of 0 for the HEAD
588 return 0 unless $trans_id;
590 return unpack( $StP{$STALE_SIZE},
591 $self->storage->read_at(
592 $self->trans_loc + $self->txn_bitfield_len + $STALE_SIZE * ($trans_id - 1),
598 sub inc_txn_staleness_counter {
602 # Hardcode staleness of 0 for the HEAD
603 return 0 unless $trans_id;
605 $self->storage->print_at(
606 $self->trans_loc + $self->txn_bitfield_len + $STALE_SIZE * ($trans_id - 1),
607 pack( $StP{$STALE_SIZE}, $self->get_txn_staleness_counter( $trans_id ) + 1 ),
613 return [ keys %{ $self->{entries}{$self->trans_id} ||= {} } ];
618 my ($trans_id, $loc) = @_;
620 $self->{entries}{$trans_id} ||= {};
621 $self->{entries}{$trans_id}{$loc} = undef;
624 # If the buckets are being relocated because of a reindexing, the entries
625 # mechanism needs to be made aware of it.
628 my ($old_loc, $new_loc) = @_;
631 while ( my ($trans_id, $locs) = each %{ $self->{entries} } ) {
632 if ( exists $locs->{$old_loc} ) {
633 delete $locs->{$old_loc};
634 $locs->{$new_loc} = undef;
642 delete $self->{entries}{$self->trans_id};
645 ################################################################################
648 my $header_fixed = length( SIG_FILE ) + 1 + 4 + 4;
649 my $this_file_version = 3;
651 sub _write_file_header {
654 my $nt = $self->num_txns;
655 my $bl = $self->txn_bitfield_len;
657 my $header_var = 1 + 1 + 1 + 1 + $bl + $STALE_SIZE * ($nt - 1) + 3 * $self->byte_size;
659 my $loc = $self->storage->request_space( $header_fixed + $header_var );
661 $self->storage->print_at( $loc,
664 pack('N', $this_file_version), # At this point, we're at 9 bytes
665 pack('N', $header_var), # header size
666 # --- Above is $header_fixed. Below is $header_var
667 pack('C', $self->byte_size),
669 # These shenanigans are to allow a 256 within a C
670 pack('C', $self->max_buckets - 1),
671 pack('C', $self->data_sector_size - 1),
674 pack('C' . $bl, 0 ), # Transaction activeness bitfield
675 pack($StP{$STALE_SIZE}.($nt-1), 0 x ($nt-1) ), # Transaction staleness counters
676 pack($StP{$self->byte_size}, 0), # Start of free chain (blist size)
677 pack($StP{$self->byte_size}, 0), # Start of free chain (data size)
678 pack($StP{$self->byte_size}, 0), # Start of free chain (index size)
681 #XXX Set these less fragilely
682 $self->set_trans_loc( $header_fixed + 4 );
683 $self->set_chains_loc( $header_fixed + 4 + $bl + $STALE_SIZE * ($nt-1) );
688 sub _read_file_header {
691 my $buffer = $self->storage->read_at( 0, $header_fixed );
692 return unless length($buffer);
694 my ($file_signature, $sig_header, $file_version, $size) = unpack(
698 unless ( $file_signature eq SIG_FILE ) {
699 $self->storage->close;
700 DBM::Deep->_throw_error( "Signature not found -- file is not a Deep DB" );
703 unless ( $sig_header eq SIG_HEADER ) {
704 $self->storage->close;
705 DBM::Deep->_throw_error( "Pre-1.00 file version found" );
708 unless ( $file_version == $this_file_version ) {
709 $self->storage->close;
710 DBM::Deep->_throw_error(
711 "Wrong file version found - " . $file_version .
712 " - expected " . $this_file_version
716 my $buffer2 = $self->storage->read_at( undef, $size );
717 my @values = unpack( 'C C C C', $buffer2 );
719 if ( @values != 4 || grep { !defined } @values ) {
720 $self->storage->close;
721 DBM::Deep->_throw_error("Corrupted file - bad header");
724 #XXX Add warnings if values weren't set right
725 @{$self}{qw(byte_size max_buckets data_sector_size num_txns)} = @values;
727 # These shenangians are to allow a 256 within a C
728 $self->{max_buckets} += 1;
729 $self->{data_sector_size} += 1;
731 my $bl = $self->txn_bitfield_len;
733 my $header_var = scalar(@values) + $bl + $STALE_SIZE * ($self->num_txns - 1) + 3 * $self->byte_size;
734 unless ( $size == $header_var ) {
735 $self->storage->close;
736 DBM::Deep->_throw_error( "Unexpected size found ($size <-> $header_var)." );
739 $self->set_trans_loc( $header_fixed + scalar(@values) );
740 $self->set_chains_loc( $header_fixed + scalar(@values) + $bl + $STALE_SIZE * ($self->num_txns - 1) );
742 return length($buffer) + length($buffer2);
750 # Add a catch for offset of 0 or 1
751 return if !$offset || $offset <= 1;
753 my $type = $self->storage->read_at( $offset, 1 );
754 return if $type eq chr(0);
756 if ( $type eq $self->SIG_ARRAY || $type eq $self->SIG_HASH ) {
757 return DBM::Deep::Engine::Sector::Reference->new({
763 # XXX Don't we need key_md5 here?
764 elsif ( $type eq $self->SIG_BLIST ) {
765 return DBM::Deep::Engine::Sector::BucketList->new({
771 elsif ( $type eq $self->SIG_INDEX ) {
772 return DBM::Deep::Engine::Sector::Index->new({
778 elsif ( $type eq $self->SIG_NULL ) {
779 return DBM::Deep::Engine::Sector::Null->new({
785 elsif ( $type eq $self->SIG_DATA ) {
786 return DBM::Deep::Engine::Sector::Scalar->new({
792 # This was deleted from under us, so just return and let the caller figure it out.
793 elsif ( $type eq $self->SIG_FREE ) {
797 DBM::Deep->_throw_error( "'$offset': Don't know what to do with type '$type'" );
802 return $self->{digest}->(@_);
805 sub _add_free_blist_sector { shift->_add_free_sector( 0, @_ ) }
806 sub _add_free_data_sector { shift->_add_free_sector( 1, @_ ) }
807 sub _add_free_index_sector { shift->_add_free_sector( 2, @_ ) }
809 sub _add_free_sector {
811 my ($multiple, $offset, $size) = @_;
813 my $chains_offset = $multiple * $self->byte_size;
815 my $storage = $self->storage;
817 # Increment staleness.
818 # XXX Can this increment+modulo be done by "&= 0x1" ?
819 my $staleness = unpack( $StP{$STALE_SIZE}, $storage->read_at( $offset + SIG_SIZE, $STALE_SIZE ) );
820 $staleness = ($staleness + 1 ) % ( 2 ** ( 8 * $STALE_SIZE ) );
821 $storage->print_at( $offset + SIG_SIZE, pack( $StP{$STALE_SIZE}, $staleness ) );
823 my $old_head = $storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
825 $storage->print_at( $self->chains_loc + $chains_offset,
826 pack( $StP{$self->byte_size}, $offset ),
829 # Record the old head in the new sector after the signature and staleness counter
830 $storage->print_at( $offset + SIG_SIZE + $STALE_SIZE, $old_head );
833 sub _request_blist_sector { shift->_request_sector( 0, @_ ) }
834 sub _request_data_sector { shift->_request_sector( 1, @_ ) }
835 sub _request_index_sector { shift->_request_sector( 2, @_ ) }
837 sub _request_sector {
839 my ($multiple, $size) = @_;
841 my $chains_offset = $multiple * $self->byte_size;
843 my $old_head = $self->storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
844 my $loc = unpack( $StP{$self->byte_size}, $old_head );
846 # We don't have any free sectors of the right size, so allocate a new one.
848 my $offset = $self->storage->request_space( $size );
850 # Zero out the new sector. This also guarantees correct increases
852 $self->storage->print_at( $offset, chr(0) x $size );
857 # Read the new head after the signature and the staleness counter
858 my $new_head = $self->storage->read_at( $loc + SIG_SIZE + $STALE_SIZE, $self->byte_size );
859 $self->storage->print_at( $self->chains_loc + $chains_offset, $new_head );
860 $self->storage->print_at(
861 $loc + SIG_SIZE + $STALE_SIZE,
862 pack( $StP{$self->byte_size}, 0 ),
868 ################################################################################
873 # my $sectors = $self->dirty_sectors;
874 # for my $offset (sort { $a <=> $b } keys %{ $sectors }) {
875 # $self->storage->print_at( $offset, $self->sector_cache->{$offset} );
878 # Why do we need to have the storage flush? Shouldn't autoflush take care of things?
880 $self->storage->flush;
882 # $self->clear_dirty_sectors;
884 # $self->clear_sector_cache;
890 return $self->storage->lock_exclusive( $obj );
896 return $self->storage->lock_shared( $obj );
903 my $rv = $self->storage->unlock( $obj );
910 ################################################################################
912 sub storage { $_[0]{storage} }
913 sub byte_size { $_[0]{byte_size} }
914 sub hash_size { $_[0]{hash_size} }
915 sub hash_chars { $_[0]{hash_chars} }
916 sub num_txns { $_[0]{num_txns} }
917 sub max_buckets { $_[0]{max_buckets} }
918 sub blank_md5 { chr(0) x $_[0]->hash_size }
919 sub data_sector_size { $_[0]{data_sector_size} }
921 # This is a calculated value
922 sub txn_bitfield_len {
924 unless ( exists $self->{txn_bitfield_len} ) {
925 my $temp = ($self->num_txns) / 8;
926 if ( $temp > int( $temp ) ) {
927 $temp = int( $temp ) + 1;
929 $self->{txn_bitfield_len} = $temp;
931 return $self->{txn_bitfield_len};
934 sub trans_id { $_[0]{trans_id} }
935 sub set_trans_id { $_[0]{trans_id} = $_[1] }
937 sub trans_loc { $_[0]{trans_loc} }
938 sub set_trans_loc { $_[0]{trans_loc} = $_[1] }
940 sub chains_loc { $_[0]{chains_loc} }
941 sub set_chains_loc { $_[0]{chains_loc} = $_[1] }
943 sub cache { $_[0]{cache} ||= {} }
944 sub clear_cache { %{$_[0]->cache} = () }
950 my $spot = $self->_read_file_header();
959 'D' => $self->data_sector_size,
960 'B' => DBM::Deep::Engine::Sector::BucketList->new({engine=>$self,offset=>1})->size,
961 'I' => DBM::Deep::Engine::Sector::Index->new({engine=>$self,offset=>1})->size,
967 $return .= "NumTxns: " . $self->num_txns . $/;
969 # Read the free sector chains
971 foreach my $multiple ( 0 .. 2 ) {
972 $return .= "Chains($types{$multiple}):";
973 my $old_loc = $self->chains_loc + $multiple * $self->byte_size;
976 $StP{$self->byte_size},
977 $self->storage->read_at( $old_loc, $self->byte_size ),
980 # We're now out of free sectors of this kind.
985 $sectors{ $types{$multiple} }{ $loc } = undef;
986 $old_loc = $loc + SIG_SIZE + $STALE_SIZE;
993 while ( $spot < $self->storage->{end} ) {
994 # Read each sector in order.
995 my $sector = $self->_load_sector( $spot );
997 # Find it in the free-sectors that were found already
998 foreach my $type ( keys %sectors ) {
999 if ( exists $sectors{$type}{$spot} ) {
1000 my $size = $sizes{$type};
1001 $return .= sprintf "%08d: %s %04d\n", $spot, 'F' . $type, $size;
1007 die "********\n$return\nDidn't find free sector for $spot in chains\n********\n";
1010 $return .= sprintf "%08d: %s %04d", $spot, $sector->type, $sector->size;
1011 if ( $sector->type eq 'D' ) {
1012 $return .= ' ' . $sector->data;
1014 elsif ( $sector->type eq 'A' || $sector->type eq 'H' ) {
1015 $return .= ' REF: ' . $sector->get_refcount;
1017 elsif ( $sector->type eq 'B' ) {
1018 foreach my $bucket ( $sector->chopped_up ) {
1020 $return .= sprintf "%08d", unpack($StP{$self->byte_size},
1021 substr( $bucket->[-1], $self->hash_size, $self->byte_size),
1023 my $l = unpack( $StP{$self->byte_size},
1024 substr( $bucket->[-1],
1025 $self->hash_size + $self->byte_size,
1029 $return .= sprintf " %08d", $l;
1030 foreach my $txn ( 0 .. $self->num_txns - 2 ) {
1031 my $l = unpack( $StP{$self->byte_size},
1032 substr( $bucket->[-1],
1033 $self->hash_size + 2 * $self->byte_size + $txn * ($self->byte_size + $STALE_SIZE),
1037 $return .= sprintf " %08d", $l;
1043 $spot += $sector->size;
1050 ################################################################################
1052 package DBM::Deep::Iterator;
1060 engine => $args->{engine},
1061 base_offset => $args->{base_offset},
1064 Scalar::Util::weaken( $self->{engine} );
1069 sub reset { $_[0]{breadcrumbs} = [] }
1071 sub get_sector_iterator {
1075 my $sector = $self->{engine}->_load_sector( $loc )
1078 if ( $sector->isa( 'DBM::Deep::Engine::Sector::Index' ) ) {
1079 return DBM::Deep::Iterator::Index->new({
1084 elsif ( $sector->isa( 'DBM::Deep::Engine::Sector::BucketList' ) ) {
1085 return DBM::Deep::Iterator::BucketList->new({
1091 DBM::Deep->_throw_error( "get_sector_iterator(): Why did $loc make a $sector?" );
1098 my $crumbs = $self->{breadcrumbs};
1099 my $e = $self->{engine};
1101 unless ( @$crumbs ) {
1102 # This will be a Reference sector
1103 my $sector = $e->_load_sector( $self->{base_offset} )
1104 # If no sector is found, thist must have been deleted from under us.
1107 if ( $sector->staleness != $obj->_staleness ) {
1111 my $loc = $sector->get_blist_loc
1114 push @$crumbs, $self->get_sector_iterator( $loc );
1119 unless ( @$crumbs ) {
1124 my $iterator = $crumbs->[-1];
1126 # This level is done.
1127 if ( $iterator->at_end ) {
1132 if ( $iterator->isa( 'DBM::Deep::Iterator::Index' ) ) {
1133 # If we don't have any more, it will be caught at the
1135 if ( my $next = $iterator->get_next_iterator ) {
1136 push @$crumbs, $next;
1141 unless ( $iterator->isa( 'DBM::Deep::Iterator::BucketList' ) ) {
1142 DBM::Deep->_throw_error(
1143 "Should have a bucketlist iterator here - instead have $iterator"
1147 # At this point, we have a BucketList iterator
1148 my $key = $iterator->get_next_key;
1149 if ( defined $key ) {
1152 #XXX else { $iterator->set_to_end() } ?
1154 # We hit the end of the bucketlist iterator, so redo
1158 DBM::Deep->_throw_error( "get_next_key(): How did we get here?" );
1161 package DBM::Deep::Iterator::Index;
1164 my $self = bless $_[1] => $_[0];
1165 $self->{curr_index} = 0;
1171 return $self->{curr_index} >= $self->{iterator}{engine}->hash_chars;
1174 sub get_next_iterator {
1179 return if $self->at_end;
1180 $loc = $self->{sector}->get_entry( $self->{curr_index}++ );
1183 return $self->{iterator}->get_sector_iterator( $loc );
1186 package DBM::Deep::Iterator::BucketList;
1189 my $self = bless $_[1] => $_[0];
1190 $self->{curr_index} = 0;
1196 return $self->{curr_index} >= $self->{iterator}{engine}->max_buckets;
1202 return if $self->at_end;
1204 my $idx = $self->{curr_index}++;
1206 my $data_loc = $self->{sector}->get_data_location_for({
1211 #XXX Do we want to add corruption checks here?
1212 return $self->{sector}->get_key_for( $idx )->data;
1215 package DBM::Deep::Engine::Sector;
1218 my $self = bless $_[1], $_[0];
1219 Scalar::Util::weaken( $self->{engine} );
1225 #sub clone { DBM::Deep->_throw_error( "Must be implemented in the child class" ); }
1227 sub engine { $_[0]{engine} }
1228 sub offset { $_[0]{offset} }
1229 sub type { $_[0]{type} }
1233 return $self->engine->SIG_SIZE + $STALE_SIZE;
1239 my $e = $self->engine;
1241 $e->storage->print_at( $self->offset, $e->SIG_FREE );
1242 # Skip staleness counter
1243 $e->storage->print_at( $self->offset + $self->base_size,
1244 chr(0) x ($self->size - $self->base_size),
1247 my $free_meth = $self->free_meth;
1248 $e->$free_meth( $self->offset, $self->size );
1253 package DBM::Deep::Engine::Sector::Data;
1255 our @ISA = qw( DBM::Deep::Engine::Sector );
1258 sub size { $_[0]{engine}->data_sector_size }
1259 sub free_meth { return '_add_free_data_sector' }
1263 return ref($self)->new({
1264 engine => $self->engine,
1265 type => $self->type,
1266 data => $self->data,
1270 package DBM::Deep::Engine::Sector::Scalar;
1272 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1277 my $chain_loc = $self->chain_loc;
1279 $self->SUPER::free();
1282 $self->engine->_load_sector( $chain_loc )->free;
1288 sub type { $_[0]{engine}->SIG_DATA }
1292 my $engine = $self->engine;
1294 unless ( $self->offset ) {
1295 my $data_section = $self->size - $self->base_size - $engine->byte_size - 1;
1297 $self->{offset} = $engine->_request_data_sector( $self->size );
1299 my $data = delete $self->{data};
1300 my $dlen = length $data;
1302 my $curr_offset = $self->offset;
1303 while ( $continue ) {
1305 my $next_offset = 0;
1307 my ($leftover, $this_len, $chunk);
1308 if ( $dlen > $data_section ) {
1310 $this_len = $data_section;
1311 $chunk = substr( $data, 0, $this_len );
1313 $dlen -= $data_section;
1314 $next_offset = $engine->_request_data_sector( $self->size );
1315 $data = substr( $data, $this_len );
1318 $leftover = $data_section - $dlen;
1325 $engine->storage->print_at( $curr_offset, $self->type ); # Sector type
1327 $engine->storage->print_at( $curr_offset + $self->base_size,
1328 pack( $StP{$engine->byte_size}, $next_offset ), # Chain loc
1329 pack( $StP{1}, $this_len ), # Data length
1330 $chunk, # Data to be stored in this sector
1331 chr(0) x $leftover, # Zero-fill the rest
1334 $curr_offset = $next_offset;
1344 my $buffer = $self->engine->storage->read_at(
1345 $self->offset + $self->base_size + $self->engine->byte_size, 1
1348 return unpack( $StP{1}, $buffer );
1354 $StP{$self->engine->byte_size},
1355 $self->engine->storage->read_at(
1356 $self->offset + $self->base_size,
1357 $self->engine->byte_size,
1369 my $chain_loc = $self->chain_loc;
1371 $data .= $self->engine->storage->read_at(
1372 $self->offset + $self->base_size + $self->engine->byte_size + 1, $self->data_length,
1375 last unless $chain_loc;
1377 $self = $self->engine->_load_sector( $chain_loc );
1383 package DBM::Deep::Engine::Sector::Null;
1385 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1387 sub type { $_[0]{engine}->SIG_NULL }
1388 sub data_length { 0 }
1394 my $engine = $self->engine;
1396 unless ( $self->offset ) {
1397 my $leftover = $self->size - $self->base_size - 1 * $engine->byte_size - 1;
1399 $self->{offset} = $engine->_request_data_sector( $self->size );
1400 $engine->storage->print_at( $self->offset, $self->type ); # Sector type
1401 # Skip staleness counter
1402 $engine->storage->print_at( $self->offset + $self->base_size,
1403 pack( $StP{$engine->byte_size}, 0 ), # Chain loc
1404 pack( $StP{1}, $self->data_length ), # Data length
1405 chr(0) x $leftover, # Zero-fill the rest
1412 package DBM::Deep::Engine::Sector::Reference;
1414 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1419 my $e = $self->engine;
1421 unless ( $self->offset ) {
1422 my $classname = Scalar::Util::blessed( delete $self->{data} );
1423 my $leftover = $self->size - $self->base_size - 3 * $e->byte_size;
1425 my $class_offset = 0;
1426 if ( defined $classname ) {
1427 my $class_sector = DBM::Deep::Engine::Sector::Scalar->new({
1431 $class_offset = $class_sector->offset;
1434 $self->{offset} = $e->_request_data_sector( $self->size );
1435 $e->storage->print_at( $self->offset, $self->type ); # Sector type
1436 # Skip staleness counter
1437 $e->storage->print_at( $self->offset + $self->base_size,
1438 pack( $StP{$e->byte_size}, 0 ), # Index/BList loc
1439 pack( $StP{$e->byte_size}, $class_offset ), # Classname loc
1440 pack( $StP{$e->byte_size}, 1 ), # Initial refcount
1441 chr(0) x $leftover, # Zero-fill the rest
1445 $self->{type} = $e->storage->read_at( $self->offset, 1 );
1448 $self->{staleness} = unpack(
1450 $e->storage->read_at( $self->offset + $e->SIG_SIZE, $STALE_SIZE ),
1456 sub staleness { $_[0]{staleness} }
1458 sub get_data_location_for {
1462 # Assume that the head is not allowed unless otherwise specified.
1463 $args->{allow_head} = 0 unless exists $args->{allow_head};
1465 # Assume we don't create a new blist location unless otherwise specified.
1466 $args->{create} = 0 unless exists $args->{create};
1468 my $blist = $self->get_bucket_list({
1469 key_md5 => $args->{key_md5},
1470 key => $args->{key},
1471 create => $args->{create},
1473 return unless $blist && $blist->{found};
1475 # At this point, $blist knows where the md5 is. What it -doesn't- know yet
1476 # is whether or not this transaction has this key. That's part of the next
1478 my $location = $blist->get_data_location_for({
1479 allow_head => $args->{allow_head},
1489 my $location = $self->get_data_location_for( $args )
1492 return $self->engine->_load_sector( $location );
1499 my $blist = $self->get_bucket_list({
1500 key_md5 => $args->{key_md5},
1501 key => $args->{key},
1503 }) or DBM::Deep->_throw_error( "How did write_data fail (no blist)?!" );
1505 # Handle any transactional bookkeeping.
1506 if ( $self->engine->trans_id ) {
1507 if ( ! $blist->has_md5 ) {
1508 $blist->mark_deleted({
1514 my @trans_ids = $self->engine->get_running_txn_ids;
1515 if ( $blist->has_md5 ) {
1517 my $old_value = $blist->get_data_for;
1518 foreach my $other_trans_id ( @trans_ids ) {
1519 next if $blist->get_data_location_for({
1520 trans_id => $other_trans_id,
1524 trans_id => $other_trans_id,
1525 key => $args->{key},
1526 key_md5 => $args->{key_md5},
1527 value => $old_value->clone,
1534 foreach my $other_trans_id ( @trans_ids ) {
1535 #XXX This doesn't seem to possible to ever happen . . .
1536 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1537 $blist->mark_deleted({
1538 trans_id => $other_trans_id,
1545 #XXX Is this safe to do transactionally?
1546 # Free the place we're about to write to.
1547 if ( $blist->get_data_location_for({ allow_head => 0 }) ) {
1548 $blist->get_data_for({ allow_head => 0 })->free;
1552 key => $args->{key},
1553 key_md5 => $args->{key_md5},
1554 value => $args->{value},
1562 # XXX What should happen if this fails?
1563 my $blist = $self->get_bucket_list({
1564 key_md5 => $args->{key_md5},
1565 }) or DBM::Deep->_throw_error( "How did delete_key fail (no blist)?!" );
1567 # Save the location so that we can free the data
1568 my $location = $blist->get_data_location_for({
1571 my $old_value = $location && $self->engine->_load_sector( $location );
1573 my @trans_ids = $self->engine->get_running_txn_ids;
1575 # If we're the HEAD and there are running txns, then we need to clone this value to the other
1576 # transactions to preserve Isolation.
1577 if ( $self->engine->trans_id == 0 ) {
1579 foreach my $other_trans_id ( @trans_ids ) {
1580 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1582 trans_id => $other_trans_id,
1583 key => $args->{key},
1584 key_md5 => $args->{key_md5},
1585 value => $old_value->clone,
1593 $blist->mark_deleted( $args );
1596 $data = $old_value->data({ export => 1 });
1601 $data = $blist->delete_md5( $args );
1610 my $e = $self->engine;
1611 my $blist_loc = $e->storage->read_at( $self->offset + $self->base_size, $e->byte_size );
1612 return unpack( $StP{$e->byte_size}, $blist_loc );
1615 sub get_bucket_list {
1620 # XXX Add in check here for recycling?
1622 my $engine = $self->engine;
1624 my $blist_loc = $self->get_blist_loc;
1626 # There's no index or blist yet
1627 unless ( $blist_loc ) {
1628 return unless $args->{create};
1630 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1632 key_md5 => $args->{key_md5},
1635 $engine->storage->print_at( $self->offset + $self->base_size,
1636 pack( $StP{$engine->byte_size}, $blist->offset ),
1642 my $sector = $engine->_load_sector( $blist_loc )
1643 or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
1645 my $last_sector = undef;
1646 while ( $sector->isa( 'DBM::Deep::Engine::Sector::Index' ) ) {
1647 $blist_loc = $sector->get_entry( ord( substr( $args->{key_md5}, $i++, 1 ) ) );
1648 $last_sector = $sector;
1650 $sector = $engine->_load_sector( $blist_loc )
1651 or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
1659 # This means we went through the Index sector(s) and found an empty slot
1660 unless ( $sector ) {
1661 return unless $args->{create};
1663 DBM::Deep->_throw_error( "No last_sector when attempting to build a new entry" )
1664 unless $last_sector;
1666 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1668 key_md5 => $args->{key_md5},
1671 $last_sector->set_entry( ord( substr( $args->{key_md5}, $i - 1, 1 ) ) => $blist->offset );
1676 $sector->find_md5( $args->{key_md5} );
1678 # See whether or not we need to reindex the bucketlist
1679 # Yes, the double-braces are there for a reason. if() doesn't create a redo-able block,
1680 # so we have to create a bare block within the if() for redo-purposes. Patch and idea
1681 # submitted by sprout@cpan.org. -RobK, 2008-01-09
1682 if ( !$sector->has_md5 && $args->{create} && $sector->{idx} == -1 ) {{
1685 my $new_index = DBM::Deep::Engine::Sector::Index->new({
1690 #XXX q.v. the comments for this function.
1691 foreach my $entry ( $sector->chopped_up ) {
1692 my ($spot, $md5) = @{$entry};
1693 my $idx = ord( substr( $md5, $i, 1 ) );
1695 # XXX This is inefficient
1696 my $blist = $blist_cache{$idx}
1697 ||= DBM::Deep::Engine::Sector::BucketList->new({
1701 $new_index->set_entry( $idx => $blist->offset );
1703 my $new_spot = $blist->write_at_next_open( $md5 );
1704 $engine->reindex_entry( $spot => $new_spot );
1707 # Handle the new item separately.
1709 my $idx = ord( substr( $args->{key_md5}, $i, 1 ) );
1711 # If all the previous blist's items have been thrown into one
1712 # blist and the new item belongs in there too, we need
1714 if ( keys %blist_cache == 1 and each %blist_cache == $idx ) {
1717 my $blist = $blist_cache{$idx}
1718 ||= DBM::Deep::Engine::Sector::BucketList->new({
1722 $new_index->set_entry( $idx => $blist->offset );
1725 $blist->find_md5( $args->{key_md5} );
1727 key => $args->{key},
1728 key_md5 => $args->{key_md5},
1729 value => DBM::Deep::Engine::Sector::Null->new({
1735 # my $blist = $blist_cache{$idx}
1736 # ||= DBM::Deep::Engine::Sector::BucketList->new({
1737 # engine => $engine,
1740 # $new_index->set_entry( $idx => $blist->offset );
1742 # #XXX THIS IS HACKY!
1743 # $blist->find_md5( $args->{key_md5} );
1744 # $blist->write_md5({
1745 # key => $args->{key},
1746 # key_md5 => $args->{key_md5},
1747 # value => DBM::Deep::Engine::Sector::Null->new({
1748 # engine => $engine,
1754 if ( $last_sector ) {
1755 $last_sector->set_entry(
1756 ord( substr( $args->{key_md5}, $i - 1, 1 ) ),
1760 $engine->storage->print_at( $self->offset + $self->base_size,
1761 pack( $StP{$engine->byte_size}, $new_index->offset ),
1769 (undef, $sector) = %blist_cache;
1770 $last_sector = $new_index;
1774 $sector = $blist_cache{ ord( substr( $args->{key_md5}, $i, 1 ) ) };
1775 $sector->find_md5( $args->{key_md5} );
1781 sub get_class_offset {
1784 my $e = $self->engine;
1786 $StP{$e->byte_size},
1787 $e->storage->read_at(
1788 $self->offset + $self->base_size + 1 * $e->byte_size, $e->byte_size,
1796 my $class_offset = $self->get_class_offset;
1798 return unless $class_offset;
1800 return $self->engine->_load_sector( $class_offset )->data;
1809 unless ( $obj = $self->engine->cache->{ $self->offset } ) {
1810 $obj = DBM::Deep->new({
1811 type => $self->type,
1812 base_offset => $self->offset,
1813 staleness => $self->staleness,
1814 storage => $self->engine->storage,
1815 engine => $self->engine,
1818 if ( $self->engine->storage->{autobless} ) {
1819 my $classname = $self->get_classname;
1820 if ( defined $classname ) {
1821 bless $obj, $classname;
1825 $self->engine->cache->{$self->offset} = $obj;
1828 # We're not exporting, so just return.
1829 unless ( $args->{export} ) {
1833 # We shouldn't export if this is still referred to.
1834 if ( $self->get_refcount > 1 ) {
1838 return $obj->export;
1844 # We're not ready to be removed yet.
1845 if ( $self->decrement_refcount > 0 ) {
1849 # Rebless the object into DBM::Deep::Null.
1850 eval { %{ $self->engine->cache->{ $self->offset } } = (); };
1851 eval { @{ $self->engine->cache->{ $self->offset } } = (); };
1852 bless $self->engine->cache->{ $self->offset }, 'DBM::Deep::Null';
1853 delete $self->engine->cache->{ $self->offset };
1855 my $blist_loc = $self->get_blist_loc;
1856 $self->engine->_load_sector( $blist_loc )->free if $blist_loc;
1858 my $class_loc = $self->get_class_offset;
1859 $self->engine->_load_sector( $class_loc )->free if $class_loc;
1861 $self->SUPER::free();
1864 sub increment_refcount {
1867 my $refcount = $self->get_refcount;
1871 $self->write_refcount( $refcount );
1876 sub decrement_refcount {
1879 my $refcount = $self->get_refcount;
1883 $self->write_refcount( $refcount );
1891 my $e = $self->engine;
1893 $StP{$e->byte_size},
1894 $e->storage->read_at(
1895 $self->offset + $self->base_size + 2 * $e->byte_size, $e->byte_size,
1900 sub write_refcount {
1904 my $e = $self->engine;
1905 $e->storage->print_at(
1906 $self->offset + $self->base_size + 2 * $e->byte_size,
1907 pack( $StP{$e->byte_size}, $num ),
1911 package DBM::Deep::Engine::Sector::BucketList;
1913 our @ISA = qw( DBM::Deep::Engine::Sector );
1918 my $engine = $self->engine;
1920 unless ( $self->offset ) {
1921 my $leftover = $self->size - $self->base_size;
1923 $self->{offset} = $engine->_request_blist_sector( $self->size );
1924 $engine->storage->print_at( $self->offset, $engine->SIG_BLIST ); # Sector type
1925 # Skip staleness counter
1926 $engine->storage->print_at( $self->offset + $self->base_size,
1927 chr(0) x $leftover, # Zero-fill the data
1931 if ( $self->{key_md5} ) {
1940 $self->engine->storage->print_at( $self->offset + $self->base_size,
1941 chr(0) x ($self->size - $self->base_size), # Zero-fill the data
1947 unless ( $self->{size} ) {
1948 my $e = $self->engine;
1949 # Base + numbuckets * bucketsize
1950 $self->{size} = $self->base_size + $e->max_buckets * $self->bucket_size;
1952 return $self->{size};
1955 sub free_meth { return '_add_free_blist_sector' }
1960 my $e = $self->engine;
1961 foreach my $bucket ( $self->chopped_up ) {
1962 my $rest = $bucket->[-1];
1964 # Delete the keysector
1965 my $l = unpack( $StP{$e->byte_size}, substr( $rest, $e->hash_size, $e->byte_size ) );
1966 my $s = $e->_load_sector( $l ); $s->free if $s;
1968 # Delete the HEAD sector
1969 $l = unpack( $StP{$e->byte_size},
1971 $e->hash_size + $e->byte_size,
1975 $s = $e->_load_sector( $l ); $s->free if $s;
1977 foreach my $txn ( 0 .. $e->num_txns - 2 ) {
1978 my $l = unpack( $StP{$e->byte_size},
1980 $e->hash_size + 2 * $e->byte_size + $txn * ($e->byte_size + $STALE_SIZE),
1984 my $s = $e->_load_sector( $l ); $s->free if $s;
1988 $self->SUPER::free();
1993 unless ( $self->{bucket_size} ) {
1994 my $e = $self->engine;
1995 # Key + head (location) + transactions (location + staleness-counter)
1996 my $location_size = $e->byte_size + $e->byte_size + ($e->num_txns - 1) * ($e->byte_size + $STALE_SIZE);
1997 $self->{bucket_size} = $e->hash_size + $location_size;
1999 return $self->{bucket_size};
2002 # XXX This is such a poor hack. I need to rethink this code.
2006 my $e = $self->engine;
2009 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
2010 my $spot = $self->offset + $self->base_size + $idx * $self->bucket_size;
2011 my $md5 = $e->storage->read_at( $spot, $e->hash_size );
2013 #XXX If we're chopping, why would we ever have the blank_md5?
2014 last if $md5 eq $e->blank_md5;
2016 my $rest = $e->storage->read_at( undef, $self->bucket_size - $e->hash_size );
2017 push @buckets, [ $spot, $md5 . $rest ];
2023 sub write_at_next_open {
2027 #XXX This is such a hack!
2028 $self->{_next_open} = 0 unless exists $self->{_next_open};
2030 my $spot = $self->offset + $self->base_size + $self->{_next_open}++ * $self->bucket_size;
2031 $self->engine->storage->print_at( $spot, $entry );
2038 unless ( exists $self->{found} ) {
2041 return $self->{found};
2047 $self->{found} = undef;
2051 $self->{key_md5} = shift;
2054 # If we don't have an MD5, then what are we supposed to do?
2055 unless ( exists $self->{key_md5} ) {
2056 DBM::Deep->_throw_error( "Cannot find_md5 without a key_md5 set" );
2059 my $e = $self->engine;
2060 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
2061 my $potential = $e->storage->read_at(
2062 $self->offset + $self->base_size + $idx * $self->bucket_size, $e->hash_size,
2065 if ( $potential eq $e->blank_md5 ) {
2066 $self->{idx} = $idx;
2070 if ( $potential eq $self->{key_md5} ) {
2072 $self->{idx} = $idx;
2084 DBM::Deep->_throw_error( "write_md5: no key" ) unless exists $args->{key};
2085 DBM::Deep->_throw_error( "write_md5: no key_md5" ) unless exists $args->{key_md5};
2086 DBM::Deep->_throw_error( "write_md5: no value" ) unless exists $args->{value};
2088 my $engine = $self->engine;
2090 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
2092 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
2093 $engine->add_entry( $args->{trans_id}, $spot );
2095 unless ($self->{found}) {
2096 my $key_sector = DBM::Deep::Engine::Sector::Scalar->new({
2098 data => $args->{key},
2101 $engine->storage->print_at( $spot,
2103 pack( $StP{$engine->byte_size}, $key_sector->offset ),
2108 + $engine->hash_size
2109 + $engine->byte_size;
2111 if ( $args->{trans_id} ) {
2112 $loc += $engine->byte_size + ($args->{trans_id} - 1) * ( $engine->byte_size + $STALE_SIZE );
2114 $engine->storage->print_at( $loc,
2115 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
2116 pack( $StP{$STALE_SIZE}, $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
2120 $engine->storage->print_at( $loc,
2121 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
2131 my $engine = $self->engine;
2133 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
2135 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
2136 $engine->add_entry( $args->{trans_id}, $spot );
2139 + $engine->hash_size
2140 + $engine->byte_size;
2142 if ( $args->{trans_id} ) {
2143 $loc += $engine->byte_size + ($args->{trans_id} - 1) * ( $engine->byte_size + $STALE_SIZE );
2145 $engine->storage->print_at( $loc,
2146 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
2147 pack( $StP{$STALE_SIZE}, $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
2151 $engine->storage->print_at( $loc,
2152 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
2162 my $engine = $self->engine;
2163 return undef unless $self->{found};
2165 # Save the location so that we can free the data
2166 my $location = $self->get_data_location_for({
2169 my $key_sector = $self->get_key_for;
2171 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
2172 $engine->storage->print_at( $spot,
2173 $engine->storage->read_at(
2174 $spot + $self->bucket_size,
2175 $self->bucket_size * ( $engine->max_buckets - $self->{idx} - 1 ),
2177 chr(0) x $self->bucket_size,
2182 my $data_sector = $self->engine->_load_sector( $location );
2183 my $data = $data_sector->data({ export => 1 });
2189 sub get_data_location_for {
2194 $args->{allow_head} = 0 unless exists $args->{allow_head};
2195 $args->{trans_id} = $self->engine->trans_id unless exists $args->{trans_id};
2196 $args->{idx} = $self->{idx} unless exists $args->{idx};
2198 my $e = $self->engine;
2200 my $spot = $self->offset + $self->base_size
2201 + $args->{idx} * $self->bucket_size
2205 if ( $args->{trans_id} ) {
2206 $spot += $e->byte_size + ($args->{trans_id} - 1) * ( $e->byte_size + $STALE_SIZE );
2209 my $buffer = $e->storage->read_at(
2211 $e->byte_size + $STALE_SIZE,
2213 my ($loc, $staleness) = unpack( $StP{$e->byte_size} . ' ' . $StP{$STALE_SIZE}, $buffer );
2215 # XXX Merge the two if-clauses below
2216 if ( $args->{trans_id} ) {
2217 # We have found an entry that is old, so get rid of it
2218 if ( $staleness != (my $s = $e->get_txn_staleness_counter( $args->{trans_id} ) ) ) {
2219 $e->storage->print_at(
2221 pack( $StP{$e->byte_size} . ' ' . $StP{$STALE_SIZE}, (0) x 2 ),
2227 # If we're in a transaction and we never wrote to this location, try the
2229 if ( $args->{trans_id} && !$loc && $args->{allow_head} ) {
2230 return $self->get_data_location_for({
2233 idx => $args->{idx},
2237 return $loc <= 1 ? 0 : $loc;
2245 return unless $self->{found};
2246 my $location = $self->get_data_location_for({
2247 allow_head => $args->{allow_head},
2249 return $self->engine->_load_sector( $location );
2255 $idx = $self->{idx} unless defined $idx;
2257 if ( $idx >= $self->engine->max_buckets ) {
2258 DBM::Deep->_throw_error( "get_key_for(): Attempting to retrieve $idx" );
2261 my $location = $self->engine->storage->read_at(
2262 $self->offset + $self->base_size + $idx * $self->bucket_size + $self->engine->hash_size,
2263 $self->engine->byte_size,
2265 $location = unpack( $StP{$self->engine->byte_size}, $location );
2266 DBM::Deep->_throw_error( "get_key_for: No location?" ) unless $location;
2268 return $self->engine->_load_sector( $location );
2271 package DBM::Deep::Engine::Sector::Index;
2273 our @ISA = qw( DBM::Deep::Engine::Sector );
2278 my $engine = $self->engine;
2280 unless ( $self->offset ) {
2281 my $leftover = $self->size - $self->base_size;
2283 $self->{offset} = $engine->_request_index_sector( $self->size );
2284 $engine->storage->print_at( $self->offset, $engine->SIG_INDEX ); # Sector type
2285 # Skip staleness counter
2286 $engine->storage->print_at( $self->offset + $self->base_size,
2287 chr(0) x $leftover, # Zero-fill the rest
2297 unless ( $self->{size} ) {
2298 my $e = $self->engine;
2299 $self->{size} = $self->base_size + $e->byte_size * $e->hash_chars;
2301 return $self->{size};
2304 sub free_meth { return '_add_free_index_sector' }
2308 my $e = $self->engine;
2310 for my $i ( 0 .. $e->hash_chars - 1 ) {
2311 my $l = $self->get_entry( $i ) or next;
2312 $e->_load_sector( $l )->free;
2315 $self->SUPER::free();
2321 return $self->offset + $self->base_size + $idx * $self->engine->byte_size;
2328 my $e = $self->engine;
2330 DBM::Deep->_throw_error( "get_entry: Out of range ($idx)" )
2331 if $idx < 0 || $idx >= $e->hash_chars;
2334 $StP{$e->byte_size},
2335 $e->storage->read_at( $self->_loc_for( $idx ), $e->byte_size ),
2341 my ($idx, $loc) = @_;
2343 my $e = $self->engine;
2345 DBM::Deep->_throw_error( "set_entry: Out of range ($idx)" )
2346 if $idx < 0 || $idx >= $e->hash_chars;
2348 $self->engine->storage->print_at(
2349 $self->_loc_for( $idx ),
2350 pack( $StP{$e->byte_size}, $loc ),
2354 # This was copied from MARCEL's Class::Null. However, I couldn't use it because
2355 # I need an undef value, not an implementation of the Null Class pattern.
2356 package DBM::Deep::Null;
2359 'bool' => sub { undef },
2360 '""' => sub { undef },
2361 '0+' => sub { undef },
2363 nomethod => 'AUTOLOAD';
2365 sub AUTOLOAD { return; }