1 package DBM::Deep::Engine;
8 our $VERSION = q(1.0010);
10 use Scalar::Util qw(refaddr reftype);
13 # * Every method in here assumes that the storage has been appropriately
14 # safeguarded. This can be anything from flock() to some sort of manual
15 # mutex. But, it's the caller's responsability to make sure that this has
18 # Setup file and tag signatures. These should never change.
19 sub SIG_FILE () { 'DPDB' }
20 sub SIG_HEADER () { 'h' }
21 sub SIG_HASH () { 'H' }
22 sub SIG_ARRAY () { 'A' }
23 sub SIG_NULL () { 'N' }
24 sub SIG_DATA () { 'D' }
25 sub SIG_INDEX () { 'I' }
26 sub SIG_BLIST () { 'B' }
27 sub SIG_FREE () { 'F' }
32 # Please refer to the pack() documentation for further information
34 1 => 'C', # Unsigned char value (no order needed as it's just one byte)
35 2 => 'n', # Unsigned short in "network" (big-endian) order
36 4 => 'N', # Unsigned long in "network" (big-endian) order
37 8 => 'Q', # Usigned quad (no order specified, presumably machine-dependent)
40 ################################################################################
50 hash_size => 16, # In bytes
51 hash_chars => 256, # Number of chars the algorithm uses per byte
53 num_txns => 1, # The HEAD
54 trans_id => 0, # Default to the HEAD
56 data_sector_size => 64, # Size in bytes of each data sector
58 entries => {}, # This is the list of entries for transactions
62 # Never allow byte_size to be set directly.
63 delete $args->{byte_size};
64 if ( defined $args->{pack_size} ) {
65 if ( lc $args->{pack_size} eq 'small' ) {
66 $args->{byte_size} = 2;
68 elsif ( lc $args->{pack_size} eq 'medium' ) {
69 $args->{byte_size} = 4;
71 elsif ( lc $args->{pack_size} eq 'large' ) {
72 $args->{byte_size} = 8;
75 DBM::Deep->_throw_error( "Unknown pack_size value: '$args->{pack_size}'" );
79 # Grab the parameters we want to use
80 foreach my $param ( keys %$self ) {
81 next unless exists $args->{$param};
82 $self->{$param} = $args->{$param};
86 max_buckets => { floor => 16, ceil => 256 },
87 num_txns => { floor => 1, ceil => 255 },
88 data_sector_size => { floor => 32, ceil => 256 },
91 while ( my ($attr, $c) = each %validations ) {
92 if ( !defined $self->{$attr}
93 || !length $self->{$attr}
94 || $self->{$attr} =~ /\D/
95 || $self->{$attr} < $c->{floor}
97 $self->{$attr} = '(undef)' if !defined $self->{$attr};
98 warn "Floor of $attr is $c->{floor}. Setting it to $c->{floor} from '$self->{$attr}'\n";
99 $self->{$attr} = $c->{floor};
101 elsif ( $self->{$attr} > $c->{ceil} ) {
102 warn "Ceiling of $attr is $c->{ceil}. Setting it to $c->{ceil} from '$self->{$attr}'\n";
103 $self->{$attr} = $c->{ceil};
107 if ( !$self->{digest} ) {
109 $self->{digest} = \&Digest::MD5::md5;
115 ################################################################################
119 my ($obj, $key) = @_;
121 # This will be a Reference sector
122 my $sector = $self->_load_sector( $obj->_base_offset )
125 if ( $sector->staleness != $obj->_staleness ) {
129 my $key_md5 = $self->_apply_digest( $key );
131 my $value_sector = $sector->get_data_for({
136 unless ( $value_sector ) {
137 $value_sector = DBM::Deep::Engine::Sector::Null->new({
142 $sector->write_data({
145 value => $value_sector,
149 return $value_sector->data;
156 # This will be a Reference sector
157 my $sector = $self->_load_sector( $obj->_base_offset )
158 or DBM::Deep->_throw_error( "How did get_classname fail (no sector for '$obj')?!" );
160 if ( $sector->staleness != $obj->_staleness ) {
164 return $sector->get_classname;
169 my ($obj, $old_key, $new_key) = @_;
171 # This will be a Reference sector
172 my $sector = $self->_load_sector( $obj->_base_offset )
173 or DBM::Deep->_throw_error( "How did get_classname fail (no sector for '$obj')?!" );
175 if ( $sector->staleness != $obj->_staleness ) {
179 my $old_md5 = $self->_apply_digest( $old_key );
181 my $value_sector = $sector->get_data_for({
186 unless ( $value_sector ) {
187 $value_sector = DBM::Deep::Engine::Sector::Null->new({
192 $sector->write_data({
195 value => $value_sector,
199 if ( $value_sector->isa( 'DBM::Deep::Engine::Sector::Reference' ) ) {
200 $sector->write_data({
202 key_md5 => $self->_apply_digest( $new_key ),
203 value => $value_sector,
205 $value_sector->increment_refcount;
208 $sector->write_data({
210 key_md5 => $self->_apply_digest( $new_key ),
211 value => $value_sector->clone,
218 my ($obj, $key) = @_;
220 # This will be a Reference sector
221 my $sector = $self->_load_sector( $obj->_base_offset )
224 if ( $sector->staleness != $obj->_staleness ) {
228 my $data = $sector->get_data_for({
229 key_md5 => $self->_apply_digest( $key ),
233 # exists() returns 1 or '' for true/false.
234 return $data ? 1 : '';
239 my ($obj, $key) = @_;
241 my $sector = $self->_load_sector( $obj->_base_offset )
244 if ( $sector->staleness != $obj->_staleness ) {
248 return $sector->delete_key({
249 key_md5 => $self->_apply_digest( $key ),
256 my ($obj, $key, $value) = @_;
258 my $r = Scalar::Util::reftype( $value ) || '';
261 last if $r eq 'HASH';
262 last if $r eq 'ARRAY';
264 DBM::Deep->_throw_error(
265 "Storage of references of type '$r' is not supported."
269 # This will be a Reference sector
270 my $sector = $self->_load_sector( $obj->_base_offset )
271 or DBM::Deep->_throw_error( "Cannot write to a deleted spot in DBM::Deep." );
273 if ( $sector->staleness != $obj->_staleness ) {
274 DBM::Deep->_throw_error( "Cannot write to a deleted spot in DBM::Deep.n" );
278 if ( !defined $value ) {
279 $class = 'DBM::Deep::Engine::Sector::Null';
281 elsif ( $r eq 'ARRAY' || $r eq 'HASH' ) {
284 # Checking if $value is tied and getting it's underlying variable
287 if ( $r eq 'ARRAY' ) {
288 $tmpvar = tied @$value;
289 } elsif ( $r eq 'HASH' ) {
290 $tmpvar = tied %$value;
294 # Checking if underlying variable is a DBM::Deep instance
296 my $is_ref_dbm_deep = eval { local $SIG{'__DIE__'}; $tmpvar->isa( 'DBM::Deep' ); };
297 if ( $is_ref_dbm_deep ) {
299 # Checking if storage of destination and source variables is the same
301 if ( $tmpvar->_engine->storage == $self->storage ) {
303 # If yes - loading source sector and getting it's data reference address
305 my $value_sector = $self->_load_sector( $tmpvar->_base_offset );
306 my $data_addr = refaddr $value_sector->data;
309 # Getting destination reference address for data by key
311 if ( reftype $sector->data eq 'ARRAY' ) {
312 $origin_addr = refaddr ${$sector->data}[$key];
313 } elsif ( reftype $sector->data eq 'HASH' ) {
314 $origin_addr = refaddr ${$sector->data}{$key};
318 # Do nothing if reference addresses of source and destination data are same
320 if (defined $data_addr && defined $origin_addr) {
321 return 1 if ($data_addr == $origin_addr);
324 DBM::Deep->_throw_error( "Cannot store values across DBM::Deep files. Please use export() instead." );
328 my $is_dbm_deep = eval { local $SIG{'__DIE__'}; $value->isa( 'DBM::Deep' ); };
329 if ( $is_dbm_deep ) {
330 if ( $value->_engine->storage == $self->storage ) {
331 my $value_sector = $self->_load_sector( $value->_base_offset );
332 $sector->write_data({
334 key_md5 => $self->_apply_digest( $key ),
335 value => $value_sector,
337 $value_sector->increment_refcount;
341 DBM::Deep->_throw_error( "Cannot store values across DBM::Deep files. Please use export() instead." );
343 if ( $r eq 'ARRAY' && tied(@$value) ) {
344 DBM::Deep->_throw_error( "Cannot store something that is tied." );
346 if ( $r eq 'HASH' && tied(%$value) ) {
347 DBM::Deep->_throw_error( "Cannot store something that is tied." );
349 $class = 'DBM::Deep::Engine::Sector::Reference';
350 $type = substr( $r, 0, 1 );
353 if ( tied($value) ) {
354 DBM::Deep->_throw_error( "Cannot store something that is tied." );
356 $class = 'DBM::Deep::Engine::Sector::Scalar';
359 # Create this after loading the reference sector in case something bad happens.
360 # This way, we won't allocate value sector(s) needlessly.
361 my $value_sector = $class->new({
366 $sector->write_data({
368 key_md5 => $self->_apply_digest( $key ),
369 value => $value_sector,
372 # This code is to make sure we write all the values in the $value to the disk
373 # and to make sure all changes to $value after the assignment are reflected
374 # on disk. This may be counter-intuitive at first, but it is correct dwimmery.
375 # NOTE - simply tying $value won't perform a STORE on each value. Hence, the
376 # copy to a temp value.
377 if ( $r eq 'ARRAY' ) {
379 tie @$value, 'DBM::Deep', {
380 base_offset => $value_sector->offset,
381 staleness => $value_sector->staleness,
382 storage => $self->storage,
386 bless $value, 'DBM::Deep::Array' unless Scalar::Util::blessed( $value );
388 elsif ( $r eq 'HASH' ) {
390 tie %$value, 'DBM::Deep', {
391 base_offset => $value_sector->offset,
392 staleness => $value_sector->staleness,
393 storage => $self->storage,
398 bless $value, 'DBM::Deep::Hash' unless Scalar::Util::blessed( $value );
404 # XXX Add staleness here
407 my ($obj, $prev_key) = @_;
409 # XXX Need to add logic about resetting the iterator if any key in the reference has changed
410 unless ( $prev_key ) {
411 $obj->{iterator} = DBM::Deep::Iterator->new({
412 base_offset => $obj->_base_offset,
417 return $obj->{iterator}->get_next_key( $obj );
420 ################################################################################
426 # We're opening the file.
427 unless ( $obj->_base_offset ) {
428 my $bytes_read = $self->_read_file_header;
430 # Creating a new file
431 unless ( $bytes_read ) {
432 $self->_write_file_header;
434 # 1) Create Array/Hash entry
435 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
439 $obj->{base_offset} = $initial_reference->offset;
440 $obj->{staleness} = $initial_reference->staleness;
442 $self->storage->flush;
444 # Reading from an existing file
446 $obj->{base_offset} = $bytes_read;
447 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
449 offset => $obj->_base_offset,
451 unless ( $initial_reference ) {
452 DBM::Deep->_throw_error("Corrupted file, no master index record");
455 unless ($obj->_type eq $initial_reference->type) {
456 DBM::Deep->_throw_error("File type mismatch");
459 $obj->{staleness} = $initial_reference->staleness;
470 if ( $self->trans_id ) {
471 DBM::Deep->_throw_error( "Cannot begin_work within an active transaction" );
474 my @slots = $self->read_txn_slots;
476 for my $i ( 0 .. $#slots ) {
480 $self->set_trans_id( $i + 1 );
485 DBM::Deep->_throw_error( "Cannot allocate transaction ID" );
487 $self->write_txn_slots( @slots );
489 if ( !$self->trans_id ) {
490 DBM::Deep->_throw_error( "Cannot begin_work - no available transactions" );
500 if ( !$self->trans_id ) {
501 DBM::Deep->_throw_error( "Cannot rollback without an active transaction" );
504 # Each entry is the file location for a bucket that has a modification for
505 # this transaction. The entries need to be expunged.
506 foreach my $entry (@{ $self->get_entries } ) {
507 # Remove the entry here
508 my $read_loc = $entry
512 + ($self->trans_id - 1) * ( $self->byte_size + $STALE_SIZE );
514 my $data_loc = $self->storage->read_at( $read_loc, $self->byte_size );
515 $data_loc = unpack( $StP{$self->byte_size}, $data_loc );
516 $self->storage->print_at( $read_loc, pack( $StP{$self->byte_size}, 0 ) );
518 if ( $data_loc > 1 ) {
519 $self->_load_sector( $data_loc )->free;
523 $self->clear_entries;
525 my @slots = $self->read_txn_slots;
526 $slots[$self->trans_id-1] = 0;
527 $self->write_txn_slots( @slots );
528 $self->inc_txn_staleness_counter( $self->trans_id );
529 $self->set_trans_id( 0 );
538 if ( !$self->trans_id ) {
539 DBM::Deep->_throw_error( "Cannot commit without an active transaction" );
542 foreach my $entry (@{ $self->get_entries } ) {
543 # Overwrite the entry in head with the entry in trans_id
548 my $head_loc = $self->storage->read_at( $base, $self->byte_size );
549 $head_loc = unpack( $StP{$self->byte_size}, $head_loc );
551 my $spot = $base + $self->byte_size + ($self->trans_id - 1) * ( $self->byte_size + $STALE_SIZE );
552 my $trans_loc = $self->storage->read_at(
553 $spot, $self->byte_size,
556 $self->storage->print_at( $base, $trans_loc );
557 $self->storage->print_at(
559 pack( $StP{$self->byte_size} . ' ' . $StP{$STALE_SIZE}, (0) x 2 ),
562 if ( $head_loc > 1 ) {
563 $self->_load_sector( $head_loc )->free;
567 $self->clear_entries;
569 my @slots = $self->read_txn_slots;
570 $slots[$self->trans_id-1] = 0;
571 $self->write_txn_slots( @slots );
572 $self->inc_txn_staleness_counter( $self->trans_id );
573 $self->set_trans_id( 0 );
580 my $bl = $self->txn_bitfield_len;
581 my $num_bits = $bl * 8;
582 return split '', unpack( 'b'.$num_bits,
583 $self->storage->read_at(
584 $self->trans_loc, $bl,
589 sub write_txn_slots {
591 my $num_bits = $self->txn_bitfield_len * 8;
592 $self->storage->print_at( $self->trans_loc,
593 pack( 'b'.$num_bits, join('', @_) ),
597 sub get_running_txn_ids {
599 my @transactions = $self->read_txn_slots;
600 my @trans_ids = map { $_+1} grep { $transactions[$_] } 0 .. $#transactions;
603 sub get_txn_staleness_counter {
607 # Hardcode staleness of 0 for the HEAD
608 return 0 unless $trans_id;
610 return unpack( $StP{$STALE_SIZE},
611 $self->storage->read_at(
612 $self->trans_loc + $self->txn_bitfield_len + $STALE_SIZE * ($trans_id - 1),
618 sub inc_txn_staleness_counter {
622 # Hardcode staleness of 0 for the HEAD
623 return 0 unless $trans_id;
625 $self->storage->print_at(
626 $self->trans_loc + $self->txn_bitfield_len + $STALE_SIZE * ($trans_id - 1),
627 pack( $StP{$STALE_SIZE}, $self->get_txn_staleness_counter( $trans_id ) + 1 ),
633 return [ keys %{ $self->{entries}{$self->trans_id} ||= {} } ];
638 my ($trans_id, $loc) = @_;
640 $self->{entries}{$trans_id} ||= {};
641 $self->{entries}{$trans_id}{$loc} = undef;
644 # If the buckets are being relocated because of a reindexing, the entries
645 # mechanism needs to be made aware of it.
648 my ($old_loc, $new_loc) = @_;
651 while ( my ($trans_id, $locs) = each %{ $self->{entries} } ) {
652 foreach my $orig_loc ( keys %{ $locs } ) {
653 if ( $orig_loc == $old_loc ) {
654 delete $locs->{orig_loc};
655 $locs->{$new_loc} = undef;
664 delete $self->{entries}{$self->trans_id};
667 ################################################################################
670 my $header_fixed = length( SIG_FILE ) + 1 + 4 + 4;
671 my $this_file_version = 3;
673 sub _write_file_header {
676 my $nt = $self->num_txns;
677 my $bl = $self->txn_bitfield_len;
679 my $header_var = 1 + 1 + 1 + 1 + $bl + $STALE_SIZE * ($nt - 1) + 3 * $self->byte_size;
681 my $loc = $self->storage->request_space( $header_fixed + $header_var );
683 $self->storage->print_at( $loc,
686 pack('N', $this_file_version), # At this point, we're at 9 bytes
687 pack('N', $header_var), # header size
688 # --- Above is $header_fixed. Below is $header_var
689 pack('C', $self->byte_size),
691 # These shenanigans are to allow a 256 within a C
692 pack('C', $self->max_buckets - 1),
693 pack('C', $self->data_sector_size - 1),
696 pack('C' . $bl, 0 ), # Transaction activeness bitfield
697 pack($StP{$STALE_SIZE}.($nt-1), 0 x ($nt-1) ), # Transaction staleness counters
698 pack($StP{$self->byte_size}, 0), # Start of free chain (blist size)
699 pack($StP{$self->byte_size}, 0), # Start of free chain (data size)
700 pack($StP{$self->byte_size}, 0), # Start of free chain (index size)
703 #XXX Set these less fragilely
704 $self->set_trans_loc( $header_fixed + 4 );
705 $self->set_chains_loc( $header_fixed + 4 + $bl + $STALE_SIZE * ($nt-1) );
710 sub _read_file_header {
713 my $buffer = $self->storage->read_at( 0, $header_fixed );
714 return unless length($buffer);
716 my ($file_signature, $sig_header, $file_version, $size) = unpack(
720 unless ( $file_signature eq SIG_FILE ) {
721 $self->storage->close;
722 DBM::Deep->_throw_error( "Signature not found -- file is not a Deep DB" );
725 unless ( $sig_header eq SIG_HEADER ) {
726 $self->storage->close;
727 DBM::Deep->_throw_error( "Pre-1.00 file version found" );
730 unless ( $file_version == $this_file_version ) {
731 $self->storage->close;
732 DBM::Deep->_throw_error(
733 "Wrong file version found - " . $file_version .
734 " - expected " . $this_file_version
738 my $buffer2 = $self->storage->read_at( undef, $size );
739 my @values = unpack( 'C C C C', $buffer2 );
741 if ( @values != 4 || grep { !defined } @values ) {
742 $self->storage->close;
743 DBM::Deep->_throw_error("Corrupted file - bad header");
746 #XXX Add warnings if values weren't set right
747 @{$self}{qw(byte_size max_buckets data_sector_size num_txns)} = @values;
749 # These shenangians are to allow a 256 within a C
750 $self->{max_buckets} += 1;
751 $self->{data_sector_size} += 1;
753 my $bl = $self->txn_bitfield_len;
755 my $header_var = scalar(@values) + $bl + $STALE_SIZE * ($self->num_txns - 1) + 3 * $self->byte_size;
756 unless ( $size == $header_var ) {
757 $self->storage->close;
758 DBM::Deep->_throw_error( "Unexpected size found ($size <-> $header_var)." );
761 $self->set_trans_loc( $header_fixed + scalar(@values) );
762 $self->set_chains_loc( $header_fixed + scalar(@values) + $bl + $STALE_SIZE * ($self->num_txns - 1) );
764 return length($buffer) + length($buffer2);
772 # Add a catch for offset of 0 or 1
773 return if !$offset || $offset <= 1;
775 my $type = $self->storage->read_at( $offset, 1 );
776 return if $type eq chr(0);
778 if ( $type eq $self->SIG_ARRAY || $type eq $self->SIG_HASH ) {
779 return DBM::Deep::Engine::Sector::Reference->new({
785 # XXX Don't we need key_md5 here?
786 elsif ( $type eq $self->SIG_BLIST ) {
787 return DBM::Deep::Engine::Sector::BucketList->new({
793 elsif ( $type eq $self->SIG_INDEX ) {
794 return DBM::Deep::Engine::Sector::Index->new({
800 elsif ( $type eq $self->SIG_NULL ) {
801 return DBM::Deep::Engine::Sector::Null->new({
807 elsif ( $type eq $self->SIG_DATA ) {
808 return DBM::Deep::Engine::Sector::Scalar->new({
814 # This was deleted from under us, so just return and let the caller figure it out.
815 elsif ( $type eq $self->SIG_FREE ) {
819 DBM::Deep->_throw_error( "'$offset': Don't know what to do with type '$type'" );
824 return $self->{digest}->(@_);
827 sub _add_free_blist_sector { shift->_add_free_sector( 0, @_ ) }
828 sub _add_free_data_sector { shift->_add_free_sector( 1, @_ ) }
829 sub _add_free_index_sector { shift->_add_free_sector( 2, @_ ) }
831 sub _add_free_sector {
833 my ($multiple, $offset, $size) = @_;
835 my $chains_offset = $multiple * $self->byte_size;
837 my $storage = $self->storage;
839 # Increment staleness.
840 # XXX Can this increment+modulo be done by "&= 0x1" ?
841 my $staleness = unpack( $StP{$STALE_SIZE}, $storage->read_at( $offset + SIG_SIZE, $STALE_SIZE ) );
842 $staleness = ($staleness + 1 ) % ( 2 ** ( 8 * $STALE_SIZE ) );
843 $storage->print_at( $offset + SIG_SIZE, pack( $StP{$STALE_SIZE}, $staleness ) );
845 my $old_head = $storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
847 $storage->print_at( $self->chains_loc + $chains_offset,
848 pack( $StP{$self->byte_size}, $offset ),
851 # Record the old head in the new sector after the signature and staleness counter
852 $storage->print_at( $offset + SIG_SIZE + $STALE_SIZE, $old_head );
855 sub _request_blist_sector { shift->_request_sector( 0, @_ ) }
856 sub _request_data_sector { shift->_request_sector( 1, @_ ) }
857 sub _request_index_sector { shift->_request_sector( 2, @_ ) }
859 sub _request_sector {
861 my ($multiple, $size) = @_;
863 my $chains_offset = $multiple * $self->byte_size;
865 my $old_head = $self->storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
866 my $loc = unpack( $StP{$self->byte_size}, $old_head );
868 # We don't have any free sectors of the right size, so allocate a new one.
870 my $offset = $self->storage->request_space( $size );
872 # Zero out the new sector. This also guarantees correct increases
874 $self->storage->print_at( $offset, chr(0) x $size );
879 # Read the new head after the signature and the staleness counter
880 my $new_head = $self->storage->read_at( $loc + SIG_SIZE + $STALE_SIZE, $self->byte_size );
881 $self->storage->print_at( $self->chains_loc + $chains_offset, $new_head );
882 $self->storage->print_at(
883 $loc + SIG_SIZE + $STALE_SIZE,
884 pack( $StP{$self->byte_size}, 0 ),
890 ################################################################################
892 sub storage { $_[0]{storage} }
893 sub byte_size { $_[0]{byte_size} }
894 sub hash_size { $_[0]{hash_size} }
895 sub hash_chars { $_[0]{hash_chars} }
896 sub num_txns { $_[0]{num_txns} }
897 sub max_buckets { $_[0]{max_buckets} }
898 sub blank_md5 { chr(0) x $_[0]->hash_size }
899 sub data_sector_size { $_[0]{data_sector_size} }
901 # This is a calculated value
902 sub txn_bitfield_len {
904 unless ( exists $self->{txn_bitfield_len} ) {
905 my $temp = ($self->num_txns) / 8;
906 if ( $temp > int( $temp ) ) {
907 $temp = int( $temp ) + 1;
909 $self->{txn_bitfield_len} = $temp;
911 return $self->{txn_bitfield_len};
914 sub trans_id { $_[0]{trans_id} }
915 sub set_trans_id { $_[0]{trans_id} = $_[1] }
917 sub trans_loc { $_[0]{trans_loc} }
918 sub set_trans_loc { $_[0]{trans_loc} = $_[1] }
920 sub chains_loc { $_[0]{chains_loc} }
921 sub set_chains_loc { $_[0]{chains_loc} = $_[1] }
923 sub cache { $_[0]{cache} ||= {} }
924 sub clear_cache { %{$_[0]->cache} = () }
930 my $spot = $self->_read_file_header();
939 'D' => $self->data_sector_size,
940 'B' => DBM::Deep::Engine::Sector::BucketList->new({engine=>$self,offset=>1})->size,
941 'I' => DBM::Deep::Engine::Sector::Index->new({engine=>$self,offset=>1})->size,
947 $return .= "NumTxns: " . $self->num_txns . $/;
949 # Read the free sector chains
951 foreach my $multiple ( 0 .. 2 ) {
952 $return .= "Chains($types{$multiple}):";
953 my $old_loc = $self->chains_loc + $multiple * $self->byte_size;
956 $StP{$self->byte_size},
957 $self->storage->read_at( $old_loc, $self->byte_size ),
960 # We're now out of free sectors of this kind.
965 $sectors{ $types{$multiple} }{ $loc } = undef;
966 $old_loc = $loc + SIG_SIZE + $STALE_SIZE;
973 while ( $spot < $self->storage->{end} ) {
974 # Read each sector in order.
975 my $sector = $self->_load_sector( $spot );
977 # Find it in the free-sectors that were found already
978 foreach my $type ( keys %sectors ) {
979 if ( exists $sectors{$type}{$spot} ) {
980 my $size = $sizes{$type};
981 $return .= sprintf "%08d: %s %04d\n", $spot, 'F' . $type, $size;
987 die "********\n$return\nDidn't find free sector for $spot in chains\n********\n";
990 $return .= sprintf "%08d: %s %04d", $spot, $sector->type, $sector->size;
991 if ( $sector->type eq 'D' ) {
992 $return .= ' ' . $sector->data;
994 elsif ( $sector->type eq 'A' || $sector->type eq 'H' ) {
995 $return .= ' REF: ' . $sector->get_refcount;
997 elsif ( $sector->type eq 'B' ) {
998 foreach my $bucket ( $sector->chopped_up ) {
1000 $return .= sprintf "%08d", unpack($StP{$self->byte_size},
1001 substr( $bucket->[-1], $self->hash_size, $self->byte_size),
1003 my $l = unpack( $StP{$self->byte_size},
1004 substr( $bucket->[-1],
1005 $self->hash_size + $self->byte_size,
1009 $return .= sprintf " %08d", $l;
1010 foreach my $txn ( 0 .. $self->num_txns - 2 ) {
1011 my $l = unpack( $StP{$self->byte_size},
1012 substr( $bucket->[-1],
1013 $self->hash_size + 2 * $self->byte_size + $txn * ($self->byte_size + $STALE_SIZE),
1017 $return .= sprintf " %08d", $l;
1023 $spot += $sector->size;
1030 ################################################################################
1032 package DBM::Deep::Iterator;
1040 engine => $args->{engine},
1041 base_offset => $args->{base_offset},
1044 Scalar::Util::weaken( $self->{engine} );
1049 sub reset { $_[0]{breadcrumbs} = [] }
1051 sub get_sector_iterator {
1055 my $sector = $self->{engine}->_load_sector( $loc )
1058 if ( $sector->isa( 'DBM::Deep::Engine::Sector::Index' ) ) {
1059 return DBM::Deep::Iterator::Index->new({
1064 elsif ( $sector->isa( 'DBM::Deep::Engine::Sector::BucketList' ) ) {
1065 return DBM::Deep::Iterator::BucketList->new({
1071 DBM::Deep->_throw_error( "get_sector_iterator(): Why did $loc make a $sector?" );
1078 my $crumbs = $self->{breadcrumbs};
1079 my $e = $self->{engine};
1081 unless ( @$crumbs ) {
1082 # This will be a Reference sector
1083 my $sector = $e->_load_sector( $self->{base_offset} )
1084 # If no sector is found, thist must have been deleted from under us.
1087 if ( $sector->staleness != $obj->_staleness ) {
1091 my $loc = $sector->get_blist_loc
1094 push @$crumbs, $self->get_sector_iterator( $loc );
1099 unless ( @$crumbs ) {
1104 my $iterator = $crumbs->[-1];
1106 # This level is done.
1107 if ( $iterator->at_end ) {
1112 if ( $iterator->isa( 'DBM::Deep::Iterator::Index' ) ) {
1113 # If we don't have any more, it will be caught at the
1115 if ( my $next = $iterator->get_next_iterator ) {
1116 push @$crumbs, $next;
1121 unless ( $iterator->isa( 'DBM::Deep::Iterator::BucketList' ) ) {
1122 DBM::Deep->_throw_error(
1123 "Should have a bucketlist iterator here - instead have $iterator"
1127 # At this point, we have a BucketList iterator
1128 my $key = $iterator->get_next_key;
1129 if ( defined $key ) {
1132 #XXX else { $iterator->set_to_end() } ?
1134 # We hit the end of the bucketlist iterator, so redo
1138 DBM::Deep->_throw_error( "get_next_key(): How did we get here?" );
1141 package DBM::Deep::Iterator::Index;
1144 my $self = bless $_[1] => $_[0];
1145 $self->{curr_index} = 0;
1151 return $self->{curr_index} >= $self->{iterator}{engine}->hash_chars;
1154 sub get_next_iterator {
1159 return if $self->at_end;
1160 $loc = $self->{sector}->get_entry( $self->{curr_index}++ );
1163 return $self->{iterator}->get_sector_iterator( $loc );
1166 package DBM::Deep::Iterator::BucketList;
1169 my $self = bless $_[1] => $_[0];
1170 $self->{curr_index} = 0;
1176 return $self->{curr_index} >= $self->{iterator}{engine}->max_buckets;
1182 return if $self->at_end;
1184 my $idx = $self->{curr_index}++;
1186 my $data_loc = $self->{sector}->get_data_location_for({
1191 #XXX Do we want to add corruption checks here?
1192 return $self->{sector}->get_key_for( $idx )->data;
1195 package DBM::Deep::Engine::Sector;
1198 my $self = bless $_[1], $_[0];
1199 Scalar::Util::weaken( $self->{engine} );
1205 #sub clone { DBM::Deep->_throw_error( "Must be implemented in the child class" ); }
1207 sub engine { $_[0]{engine} }
1208 sub offset { $_[0]{offset} }
1209 sub type { $_[0]{type} }
1213 return $self->engine->SIG_SIZE + $STALE_SIZE;
1219 my $e = $self->engine;
1221 $e->storage->print_at( $self->offset, $e->SIG_FREE );
1222 # Skip staleness counter
1223 $e->storage->print_at( $self->offset + $self->base_size,
1224 chr(0) x ($self->size - $self->base_size),
1227 my $free_meth = $self->free_meth;
1228 $e->$free_meth( $self->offset, $self->size );
1233 package DBM::Deep::Engine::Sector::Data;
1235 our @ISA = qw( DBM::Deep::Engine::Sector );
1238 sub size { $_[0]{engine}->data_sector_size }
1239 sub free_meth { return '_add_free_data_sector' }
1243 return ref($self)->new({
1244 engine => $self->engine,
1245 type => $self->type,
1246 data => $self->data,
1250 package DBM::Deep::Engine::Sector::Scalar;
1252 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1257 my $chain_loc = $self->chain_loc;
1259 $self->SUPER::free();
1262 $self->engine->_load_sector( $chain_loc )->free;
1268 sub type { $_[0]{engine}->SIG_DATA }
1272 my $engine = $self->engine;
1274 unless ( $self->offset ) {
1275 my $data_section = $self->size - $self->base_size - $engine->byte_size - 1;
1277 $self->{offset} = $engine->_request_data_sector( $self->size );
1279 my $data = delete $self->{data};
1280 my $dlen = length $data;
1282 my $curr_offset = $self->offset;
1283 while ( $continue ) {
1285 my $next_offset = 0;
1287 my ($leftover, $this_len, $chunk);
1288 if ( $dlen > $data_section ) {
1290 $this_len = $data_section;
1291 $chunk = substr( $data, 0, $this_len );
1293 $dlen -= $data_section;
1294 $next_offset = $engine->_request_data_sector( $self->size );
1295 $data = substr( $data, $this_len );
1298 $leftover = $data_section - $dlen;
1305 $engine->storage->print_at( $curr_offset, $self->type ); # Sector type
1307 $engine->storage->print_at( $curr_offset + $self->base_size,
1308 pack( $StP{$engine->byte_size}, $next_offset ), # Chain loc
1309 pack( $StP{1}, $this_len ), # Data length
1310 $chunk, # Data to be stored in this sector
1311 chr(0) x $leftover, # Zero-fill the rest
1314 $curr_offset = $next_offset;
1324 my $buffer = $self->engine->storage->read_at(
1325 $self->offset + $self->base_size + $self->engine->byte_size, 1
1328 return unpack( $StP{1}, $buffer );
1334 $StP{$self->engine->byte_size},
1335 $self->engine->storage->read_at(
1336 $self->offset + $self->base_size,
1337 $self->engine->byte_size,
1347 my $chain_loc = $self->chain_loc;
1349 $data .= $self->engine->storage->read_at(
1350 $self->offset + $self->base_size + $self->engine->byte_size + 1, $self->data_length,
1353 last unless $chain_loc;
1355 $self = $self->engine->_load_sector( $chain_loc );
1361 package DBM::Deep::Engine::Sector::Null;
1363 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1365 sub type { $_[0]{engine}->SIG_NULL }
1366 sub data_length { 0 }
1372 my $engine = $self->engine;
1374 unless ( $self->offset ) {
1375 my $leftover = $self->size - $self->base_size - 1 * $engine->byte_size - 1;
1377 $self->{offset} = $engine->_request_data_sector( $self->size );
1378 $engine->storage->print_at( $self->offset, $self->type ); # Sector type
1379 # Skip staleness counter
1380 $engine->storage->print_at( $self->offset + $self->base_size,
1381 pack( $StP{$engine->byte_size}, 0 ), # Chain loc
1382 pack( $StP{1}, $self->data_length ), # Data length
1383 chr(0) x $leftover, # Zero-fill the rest
1390 package DBM::Deep::Engine::Sector::Reference;
1392 our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1397 my $e = $self->engine;
1399 unless ( $self->offset ) {
1400 my $classname = Scalar::Util::blessed( delete $self->{data} );
1401 my $leftover = $self->size - $self->base_size - 3 * $e->byte_size;
1403 my $class_offset = 0;
1404 if ( defined $classname ) {
1405 my $class_sector = DBM::Deep::Engine::Sector::Scalar->new({
1409 $class_offset = $class_sector->offset;
1412 $self->{offset} = $e->_request_data_sector( $self->size );
1413 $e->storage->print_at( $self->offset, $self->type ); # Sector type
1414 # Skip staleness counter
1415 $e->storage->print_at( $self->offset + $self->base_size,
1416 pack( $StP{$e->byte_size}, 0 ), # Index/BList loc
1417 pack( $StP{$e->byte_size}, $class_offset ), # Classname loc
1418 pack( $StP{$e->byte_size}, 1 ), # Initial refcount
1419 chr(0) x $leftover, # Zero-fill the rest
1423 $self->{type} = $e->storage->read_at( $self->offset, 1 );
1426 $self->{staleness} = unpack(
1428 $e->storage->read_at( $self->offset + $e->SIG_SIZE, $STALE_SIZE ),
1434 sub staleness { $_[0]{staleness} }
1440 # Assume that the head is not allowed unless otherwise specified.
1441 $args->{allow_head} = 0 unless exists $args->{allow_head};
1443 # Assume we don't create a new blist location unless otherwise specified.
1444 $args->{create} = 0 unless exists $args->{create};
1446 my $blist = $self->get_bucket_list({
1447 key_md5 => $args->{key_md5},
1448 key => $args->{key},
1449 create => $args->{create},
1451 return unless $blist && $blist->{found};
1453 # At this point, $blist knows where the md5 is. What it -doesn't- know yet
1454 # is whether or not this transaction has this key. That's part of the next
1456 my $location = $blist->get_data_location_for({
1457 allow_head => $args->{allow_head},
1460 return $self->engine->_load_sector( $location );
1467 my $blist = $self->get_bucket_list({
1468 key_md5 => $args->{key_md5},
1469 key => $args->{key},
1471 }) or DBM::Deep->_throw_error( "How did write_data fail (no blist)?!" );
1473 # Handle any transactional bookkeeping.
1474 if ( $self->engine->trans_id ) {
1475 if ( ! $blist->has_md5 ) {
1476 $blist->mark_deleted({
1482 my @trans_ids = $self->engine->get_running_txn_ids;
1483 if ( $blist->has_md5 ) {
1485 my $old_value = $blist->get_data_for;
1486 foreach my $other_trans_id ( @trans_ids ) {
1487 next if $blist->get_data_location_for({
1488 trans_id => $other_trans_id,
1492 trans_id => $other_trans_id,
1493 key => $args->{key},
1494 key_md5 => $args->{key_md5},
1495 value => $old_value->clone,
1502 foreach my $other_trans_id ( @trans_ids ) {
1503 #XXX This doesn't seem to possible to ever happen . . .
1504 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1505 $blist->mark_deleted({
1506 trans_id => $other_trans_id,
1513 #XXX Is this safe to do transactionally?
1514 # Free the place we're about to write to.
1515 if ( $blist->get_data_location_for({ allow_head => 0 }) ) {
1516 $blist->get_data_for({ allow_head => 0 })->free;
1520 key => $args->{key},
1521 key_md5 => $args->{key_md5},
1522 value => $args->{value},
1530 # XXX What should happen if this fails?
1531 my $blist = $self->get_bucket_list({
1532 key_md5 => $args->{key_md5},
1533 }) or DBM::Deep->_throw_error( "How did delete_key fail (no blist)?!" );
1535 # Save the location so that we can free the data
1536 my $location = $blist->get_data_location_for({
1539 my $old_value = $location && $self->engine->_load_sector( $location );
1541 my @trans_ids = $self->engine->get_running_txn_ids;
1543 # If we're the HEAD and there are running txns, then we need to clone this value to the other
1544 # transactions to preserve Isolation.
1545 if ( $self->engine->trans_id == 0 ) {
1547 foreach my $other_trans_id ( @trans_ids ) {
1548 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1550 trans_id => $other_trans_id,
1551 key => $args->{key},
1552 key_md5 => $args->{key_md5},
1553 value => $old_value->clone,
1561 $blist->mark_deleted( $args );
1564 $data = $old_value->data;
1569 $data = $blist->delete_md5( $args );
1578 my $e = $self->engine;
1579 my $blist_loc = $e->storage->read_at( $self->offset + $self->base_size, $e->byte_size );
1580 return unpack( $StP{$e->byte_size}, $blist_loc );
1583 sub get_bucket_list {
1588 # XXX Add in check here for recycling?
1590 my $engine = $self->engine;
1592 my $blist_loc = $self->get_blist_loc;
1594 # There's no index or blist yet
1595 unless ( $blist_loc ) {
1596 return unless $args->{create};
1598 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1600 key_md5 => $args->{key_md5},
1603 $engine->storage->print_at( $self->offset + $self->base_size,
1604 pack( $StP{$engine->byte_size}, $blist->offset ),
1610 my $sector = $engine->_load_sector( $blist_loc )
1611 or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
1613 my $last_sector = undef;
1614 while ( $sector->isa( 'DBM::Deep::Engine::Sector::Index' ) ) {
1615 $blist_loc = $sector->get_entry( ord( substr( $args->{key_md5}, $i++, 1 ) ) );
1616 $last_sector = $sector;
1618 $sector = $engine->_load_sector( $blist_loc )
1619 or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
1627 # This means we went through the Index sector(s) and found an empty slot
1628 unless ( $sector ) {
1629 return unless $args->{create};
1631 DBM::Deep->_throw_error( "No last_sector when attempting to build a new entry" )
1632 unless $last_sector;
1634 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1636 key_md5 => $args->{key_md5},
1639 $last_sector->set_entry( ord( substr( $args->{key_md5}, $i - 1, 1 ) ) => $blist->offset );
1644 $sector->find_md5( $args->{key_md5} );
1646 # See whether or not we need to reindex the bucketlist
1647 # Yes, the double-braces are there for a reason. if() doesn't create a redo-able block,
1648 # so we have to create a bare block within the if() for redo-purposes. Patch and idea
1649 # submitted by sprout@cpan.org. -RobK, 2008-01-09
1650 if ( !$sector->has_md5 && $args->{create} && $sector->{idx} == -1 ) {{
1653 my $new_index = DBM::Deep::Engine::Sector::Index->new({
1658 #XXX q.v. the comments for this function.
1659 foreach my $entry ( $sector->chopped_up ) {
1660 my ($spot, $md5) = @{$entry};
1661 my $idx = ord( substr( $md5, $i, 1 ) );
1663 # XXX This is inefficient
1664 my $blist = $blist_cache{$idx}
1665 ||= DBM::Deep::Engine::Sector::BucketList->new({
1669 $new_index->set_entry( $idx => $blist->offset );
1671 my $new_spot = $blist->write_at_next_open( $md5 );
1672 $engine->reindex_entry( $spot => $new_spot );
1675 # Handle the new item separately.
1677 my $idx = ord( substr( $args->{key_md5}, $i, 1 ) );
1679 # If all the previous blist's items have been thrown into one
1680 # blist and the new item belongs in there too, we need
1682 if ( keys %blist_cache == 1 and each %blist_cache == $idx ) {
1685 my $blist = $blist_cache{$idx}
1686 ||= DBM::Deep::Engine::Sector::BucketList->new({
1690 $new_index->set_entry( $idx => $blist->offset );
1693 $blist->find_md5( $args->{key_md5} );
1695 key => $args->{key},
1696 key_md5 => $args->{key_md5},
1697 value => DBM::Deep::Engine::Sector::Null->new({
1703 # my $blist = $blist_cache{$idx}
1704 # ||= DBM::Deep::Engine::Sector::BucketList->new({
1705 # engine => $engine,
1708 # $new_index->set_entry( $idx => $blist->offset );
1710 # #XXX THIS IS HACKY!
1711 # $blist->find_md5( $args->{key_md5} );
1712 # $blist->write_md5({
1713 # key => $args->{key},
1714 # key_md5 => $args->{key_md5},
1715 # value => DBM::Deep::Engine::Sector::Null->new({
1716 # engine => $engine,
1722 if ( $last_sector ) {
1723 $last_sector->set_entry(
1724 ord( substr( $args->{key_md5}, $i - 1, 1 ) ),
1728 $engine->storage->print_at( $self->offset + $self->base_size,
1729 pack( $StP{$engine->byte_size}, $new_index->offset ),
1737 (undef, $sector) = %blist_cache;
1738 $last_sector = $new_index;
1742 $sector = $blist_cache{ ord( substr( $args->{key_md5}, $i, 1 ) ) };
1743 $sector->find_md5( $args->{key_md5} );
1749 sub get_class_offset {
1752 my $e = $self->engine;
1754 $StP{$e->byte_size},
1755 $e->storage->read_at(
1756 $self->offset + $self->base_size + 1 * $e->byte_size, $e->byte_size,
1764 my $class_offset = $self->get_class_offset;
1766 return unless $class_offset;
1768 return $self->engine->_load_sector( $class_offset )->data;
1774 unless ( $self->engine->cache->{ $self->offset } ) {
1775 my $new_obj = DBM::Deep->new({
1776 type => $self->type,
1777 base_offset => $self->offset,
1778 staleness => $self->staleness,
1779 storage => $self->engine->storage,
1780 engine => $self->engine,
1783 if ( $self->engine->storage->{autobless} ) {
1784 my $classname = $self->get_classname;
1785 if ( defined $classname ) {
1786 bless $new_obj, $classname;
1790 $self->engine->cache->{$self->offset} = $new_obj;
1792 return $self->engine->cache->{$self->offset};
1798 # We're not ready to be removed yet.
1799 if ( $self->decrement_refcount > 0 ) {
1803 # Rebless the object into DBM::Deep::Null.
1804 eval { %{ $self->engine->cache->{ $self->offset } } = (); };
1805 eval { @{ $self->engine->cache->{ $self->offset } } = (); };
1806 bless $self->engine->cache->{ $self->offset }, 'DBM::Deep::Null';
1807 delete $self->engine->cache->{ $self->offset };
1809 my $blist_loc = $self->get_blist_loc;
1810 $self->engine->_load_sector( $blist_loc )->free if $blist_loc;
1812 my $class_loc = $self->get_class_offset;
1813 $self->engine->_load_sector( $class_loc )->free if $class_loc;
1815 $self->SUPER::free();
1818 sub increment_refcount {
1821 my $refcount = $self->get_refcount;
1825 $self->write_refcount( $refcount );
1830 sub decrement_refcount {
1833 my $refcount = $self->get_refcount;
1837 $self->write_refcount( $refcount );
1845 my $e = $self->engine;
1847 $StP{$e->byte_size},
1848 $e->storage->read_at(
1849 $self->offset + $self->base_size + 2 * $e->byte_size, $e->byte_size,
1854 sub write_refcount {
1858 my $e = $self->engine;
1859 $e->storage->print_at(
1860 $self->offset + $self->base_size + 2 * $e->byte_size,
1861 pack( $StP{$e->byte_size}, $num ),
1865 package DBM::Deep::Engine::Sector::BucketList;
1867 our @ISA = qw( DBM::Deep::Engine::Sector );
1872 my $engine = $self->engine;
1874 unless ( $self->offset ) {
1875 my $leftover = $self->size - $self->base_size;
1877 $self->{offset} = $engine->_request_blist_sector( $self->size );
1878 $engine->storage->print_at( $self->offset, $engine->SIG_BLIST ); # Sector type
1879 # Skip staleness counter
1880 $engine->storage->print_at( $self->offset + $self->base_size,
1881 chr(0) x $leftover, # Zero-fill the data
1885 if ( $self->{key_md5} ) {
1894 $self->engine->storage->print_at( $self->offset + $self->base_size,
1895 chr(0) x ($self->size - $self->base_size), # Zero-fill the data
1901 unless ( $self->{size} ) {
1902 my $e = $self->engine;
1903 # Base + numbuckets * bucketsize
1904 $self->{size} = $self->base_size + $e->max_buckets * $self->bucket_size;
1906 return $self->{size};
1909 sub free_meth { return '_add_free_blist_sector' }
1914 my $e = $self->engine;
1915 foreach my $bucket ( $self->chopped_up ) {
1916 my $rest = $bucket->[-1];
1918 # Delete the keysector
1919 my $l = unpack( $StP{$e->byte_size}, substr( $rest, $e->hash_size, $e->byte_size ) );
1920 my $s = $e->_load_sector( $l ); $s->free if $s;
1922 # Delete the HEAD sector
1923 $l = unpack( $StP{$e->byte_size},
1925 $e->hash_size + $e->byte_size,
1929 $s = $e->_load_sector( $l ); $s->free if $s;
1931 foreach my $txn ( 0 .. $e->num_txns - 2 ) {
1932 my $l = unpack( $StP{$e->byte_size},
1934 $e->hash_size + 2 * $e->byte_size + $txn * ($e->byte_size + $STALE_SIZE),
1938 my $s = $e->_load_sector( $l ); $s->free if $s;
1942 $self->SUPER::free();
1947 unless ( $self->{bucket_size} ) {
1948 my $e = $self->engine;
1949 # Key + head (location) + transactions (location + staleness-counter)
1950 my $location_size = $e->byte_size + $e->byte_size + ($e->num_txns - 1) * ($e->byte_size + $STALE_SIZE);
1951 $self->{bucket_size} = $e->hash_size + $location_size;
1953 return $self->{bucket_size};
1956 # XXX This is such a poor hack. I need to rethink this code.
1960 my $e = $self->engine;
1963 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
1964 my $spot = $self->offset + $self->base_size + $idx * $self->bucket_size;
1965 my $md5 = $e->storage->read_at( $spot, $e->hash_size );
1967 #XXX If we're chopping, why would we ever have the blank_md5?
1968 last if $md5 eq $e->blank_md5;
1970 my $rest = $e->storage->read_at( undef, $self->bucket_size - $e->hash_size );
1971 push @buckets, [ $spot, $md5 . $rest ];
1977 sub write_at_next_open {
1981 #XXX This is such a hack!
1982 $self->{_next_open} = 0 unless exists $self->{_next_open};
1984 my $spot = $self->offset + $self->base_size + $self->{_next_open}++ * $self->bucket_size;
1985 $self->engine->storage->print_at( $spot, $entry );
1992 unless ( exists $self->{found} ) {
1995 return $self->{found};
2001 $self->{found} = undef;
2005 $self->{key_md5} = shift;
2008 # If we don't have an MD5, then what are we supposed to do?
2009 unless ( exists $self->{key_md5} ) {
2010 DBM::Deep->_throw_error( "Cannot find_md5 without a key_md5 set" );
2013 my $e = $self->engine;
2014 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
2015 my $potential = $e->storage->read_at(
2016 $self->offset + $self->base_size + $idx * $self->bucket_size, $e->hash_size,
2019 if ( $potential eq $e->blank_md5 ) {
2020 $self->{idx} = $idx;
2024 if ( $potential eq $self->{key_md5} ) {
2026 $self->{idx} = $idx;
2038 DBM::Deep->_throw_error( "write_md5: no key" ) unless exists $args->{key};
2039 DBM::Deep->_throw_error( "write_md5: no key_md5" ) unless exists $args->{key_md5};
2040 DBM::Deep->_throw_error( "write_md5: no value" ) unless exists $args->{value};
2042 my $engine = $self->engine;
2044 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
2046 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
2047 $engine->add_entry( $args->{trans_id}, $spot );
2049 unless ($self->{found}) {
2050 my $key_sector = DBM::Deep::Engine::Sector::Scalar->new({
2052 data => $args->{key},
2055 $engine->storage->print_at( $spot,
2057 pack( $StP{$engine->byte_size}, $key_sector->offset ),
2062 + $engine->hash_size
2063 + $engine->byte_size;
2065 if ( $args->{trans_id} ) {
2066 $loc += $engine->byte_size + ($args->{trans_id} - 1) * ( $engine->byte_size + $STALE_SIZE );
2068 $engine->storage->print_at( $loc,
2069 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
2070 pack( $StP{$STALE_SIZE}, $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
2074 $engine->storage->print_at( $loc,
2075 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
2085 my $engine = $self->engine;
2087 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
2089 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
2090 $engine->add_entry( $args->{trans_id}, $spot );
2093 + $engine->hash_size
2094 + $engine->byte_size;
2096 if ( $args->{trans_id} ) {
2097 $loc += $engine->byte_size + ($args->{trans_id} - 1) * ( $engine->byte_size + $STALE_SIZE );
2099 $engine->storage->print_at( $loc,
2100 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
2101 pack( $StP{$STALE_SIZE}, $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
2105 $engine->storage->print_at( $loc,
2106 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
2116 my $engine = $self->engine;
2117 return undef unless $self->{found};
2119 # Save the location so that we can free the data
2120 my $location = $self->get_data_location_for({
2123 my $key_sector = $self->get_key_for;
2125 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
2126 $engine->storage->print_at( $spot,
2127 $engine->storage->read_at(
2128 $spot + $self->bucket_size,
2129 $self->bucket_size * ( $engine->max_buckets - $self->{idx} - 1 ),
2131 chr(0) x $self->bucket_size,
2136 my $data_sector = $self->engine->_load_sector( $location );
2137 my $data = $data_sector->data;
2143 sub get_data_location_for {
2148 $args->{allow_head} = 0 unless exists $args->{allow_head};
2149 $args->{trans_id} = $self->engine->trans_id unless exists $args->{trans_id};
2150 $args->{idx} = $self->{idx} unless exists $args->{idx};
2152 my $e = $self->engine;
2154 my $spot = $self->offset + $self->base_size
2155 + $args->{idx} * $self->bucket_size
2159 if ( $args->{trans_id} ) {
2160 $spot += $e->byte_size + ($args->{trans_id} - 1) * ( $e->byte_size + $STALE_SIZE );
2163 my $buffer = $e->storage->read_at(
2165 $e->byte_size + $STALE_SIZE,
2167 my ($loc, $staleness) = unpack( $StP{$e->byte_size} . ' ' . $StP{$STALE_SIZE}, $buffer );
2169 # XXX Merge the two if-clauses below
2170 if ( $args->{trans_id} ) {
2171 # We have found an entry that is old, so get rid of it
2172 if ( $staleness != (my $s = $e->get_txn_staleness_counter( $args->{trans_id} ) ) ) {
2173 $e->storage->print_at(
2175 pack( $StP{$e->byte_size} . ' ' . $StP{$STALE_SIZE}, (0) x 2 ),
2181 # If we're in a transaction and we never wrote to this location, try the
2183 if ( $args->{trans_id} && !$loc && $args->{allow_head} ) {
2184 return $self->get_data_location_for({
2187 idx => $args->{idx},
2191 return $loc <= 1 ? 0 : $loc;
2199 return unless $self->{found};
2200 my $location = $self->get_data_location_for({
2201 allow_head => $args->{allow_head},
2203 return $self->engine->_load_sector( $location );
2209 $idx = $self->{idx} unless defined $idx;
2211 if ( $idx >= $self->engine->max_buckets ) {
2212 DBM::Deep->_throw_error( "get_key_for(): Attempting to retrieve $idx" );
2215 my $location = $self->engine->storage->read_at(
2216 $self->offset + $self->base_size + $idx * $self->bucket_size + $self->engine->hash_size,
2217 $self->engine->byte_size,
2219 $location = unpack( $StP{$self->engine->byte_size}, $location );
2220 DBM::Deep->_throw_error( "get_key_for: No location?" ) unless $location;
2222 return $self->engine->_load_sector( $location );
2225 package DBM::Deep::Engine::Sector::Index;
2227 our @ISA = qw( DBM::Deep::Engine::Sector );
2232 my $engine = $self->engine;
2234 unless ( $self->offset ) {
2235 my $leftover = $self->size - $self->base_size;
2237 $self->{offset} = $engine->_request_index_sector( $self->size );
2238 $engine->storage->print_at( $self->offset, $engine->SIG_INDEX ); # Sector type
2239 # Skip staleness counter
2240 $engine->storage->print_at( $self->offset + $self->base_size,
2241 chr(0) x $leftover, # Zero-fill the rest
2251 unless ( $self->{size} ) {
2252 my $e = $self->engine;
2253 $self->{size} = $self->base_size + $e->byte_size * $e->hash_chars;
2255 return $self->{size};
2258 sub free_meth { return '_add_free_index_sector' }
2262 my $e = $self->engine;
2264 for my $i ( 0 .. $e->hash_chars - 1 ) {
2265 my $l = $self->get_entry( $i ) or next;
2266 $e->_load_sector( $l )->free;
2269 $self->SUPER::free();
2275 return $self->offset + $self->base_size + $idx * $self->engine->byte_size;
2282 my $e = $self->engine;
2284 DBM::Deep->_throw_error( "get_entry: Out of range ($idx)" )
2285 if $idx < 0 || $idx >= $e->hash_chars;
2288 $StP{$e->byte_size},
2289 $e->storage->read_at( $self->_loc_for( $idx ), $e->byte_size ),
2295 my ($idx, $loc) = @_;
2297 my $e = $self->engine;
2299 DBM::Deep->_throw_error( "set_entry: Out of range ($idx)" )
2300 if $idx < 0 || $idx >= $e->hash_chars;
2302 $self->engine->storage->print_at(
2303 $self->_loc_for( $idx ),
2304 pack( $StP{$e->byte_size}, $loc ),
2308 # This was copied from MARCEL's Class::Null. However, I couldn't use it because
2309 # I need an undef value, not an implementation of the Null Class pattern.
2310 package DBM::Deep::Null;
2313 'bool' => sub { undef },
2314 '""' => sub { undef },
2315 '0+' => sub { undef },
2317 nomethod => 'AUTOLOAD';
2319 sub AUTOLOAD { return; }