Fixed hardcoded 0 staleness for HEAD in inc_txn_staleness_counter
[dbsrgits/DBM-Deep.git] / lib / DBM / Deep / Engine.pm
CommitLineData
a20d9a3f 1package DBM::Deep::Engine;
2
b48ae6ec 3use 5.006_000;
460b1067 4
a20d9a3f 5use strict;
f72b2dfb 6use warnings;
a20d9a3f 7
9f83dc31 8our $VERSION = q(1.0004);
86867f3a 9
359a01ac 10use Scalar::Util ();
a20d9a3f 11
21838116 12# File-wide notes:
9a63e1f2 13# * Every method in here assumes that the storage has been appropriately
c3aafc14 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
16# been done.
21838116 17
8db25060 18# Setup file and tag signatures. These should never change.
8db25060 19sub SIG_FILE () { 'DPDB' }
460b1067 20sub SIG_HEADER () { 'h' }
8db25060 21sub SIG_HASH () { 'H' }
22sub SIG_ARRAY () { 'A' }
8db25060 23sub SIG_NULL () { 'N' }
24sub SIG_DATA () { 'D' }
25sub SIG_INDEX () { 'I' }
26sub SIG_BLIST () { 'B' }
7b1e1aa1 27sub SIG_FREE () { 'F' }
8db25060 28sub SIG_SIZE () { 1 }
f72b2dfb 29
30my $STALE_SIZE = 2;
8db25060 31
9a63e1f2 32# Please refer to the pack() documentation for further information
33my %StP = (
f72b2dfb 34 1 => 'C', # Unsigned char value (no order needed as it's just one byte)
9a63e1f2 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)
38);
83371fe3 39
c3aafc14 40################################################################################
c3aafc14 41
612969fb 42sub new {
43 my $class = shift;
44 my ($args) = @_;
45
46 my $self = bless {
9a63e1f2 47 byte_size => 4,
48
49 digest => undef,
50 hash_size => 16, # In bytes
51 hash_chars => 256, # Number of chars the algorithm uses per byte
612969fb 52 max_buckets => 16,
f72b2dfb 53 num_txns => 1, # The HEAD
9a63e1f2 54 trans_id => 0, # Default to the HEAD
460b1067 55
f72b2dfb 56 data_sector_size => 64, # Size in bytes of each data sector
57
9a63e1f2 58 entries => {}, # This is the list of entries for transactions
83371fe3 59 storage => undef,
612969fb 60 }, $class;
61
f72b2dfb 62 # Never allow byte_size to be set directly.
63 delete $args->{byte_size};
e0098e7f 64 if ( defined $args->{pack_size} ) {
65 if ( lc $args->{pack_size} eq 'small' ) {
9a63e1f2 66 $args->{byte_size} = 2;
e0098e7f 67 }
68 elsif ( lc $args->{pack_size} eq 'medium' ) {
9a63e1f2 69 $args->{byte_size} = 4;
e0098e7f 70 }
71 elsif ( lc $args->{pack_size} eq 'large' ) {
9a63e1f2 72 $args->{byte_size} = 8;
e0098e7f 73 }
74 else {
9a63e1f2 75 DBM::Deep->_throw_error( "Unknown pack_size value: '$args->{pack_size}'" );
e0098e7f 76 }
77 }
78
fde3db1a 79 # Grab the parameters we want to use
80 foreach my $param ( keys %$self ) {
81 next unless exists $args->{$param};
3e9498a1 82 $self->{$param} = $args->{$param};
fde3db1a 83 }
84
f72b2dfb 85 my %validations = (
86 max_buckets => { floor => 16, ceil => 256 },
87 num_txns => { floor => 1, ceil => 255 },
88 data_sector_size => { floor => 32, ceil => 256 },
89 );
90
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}
96 ) {
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};
100 }
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} = $c->{ceil};
104 }
e0098e7f 105 }
106
9a63e1f2 107 if ( !$self->{digest} ) {
108 require Digest::MD5;
109 $self->{digest} = \&Digest::MD5::md5;
110 }
111
260a80b4 112 return $self;
113}
114
9a63e1f2 115################################################################################
460b1067 116
9a63e1f2 117sub read_value {
c3aafc14 118 my $self = shift;
9a63e1f2 119 my ($obj, $key) = @_;
120
121 # This will be a Reference sector
122 my $sector = $self->_load_sector( $obj->_base_offset )
123 or return;
124
125 if ( $sector->staleness != $obj->_staleness ) {
126 return;
127 }
128
129 my $key_md5 = $self->_apply_digest( $key );
130
131 my $value_sector = $sector->get_data_for({
132 key_md5 => $key_md5,
133 allow_head => 1,
134 });
135
136 unless ( $value_sector ) {
137 $value_sector = DBM::Deep::Engine::Sector::Null->new({
138 engine => $self,
139 data => undef,
140 });
141
142 $sector->write_data({
143 key_md5 => $key_md5,
144 key => $key,
145 value => $value_sector,
146 });
147 }
148
149 return $value_sector->data;
c3aafc14 150}
151
9a63e1f2 152sub get_classname {
260a80b4 153 my $self = shift;
9a63e1f2 154 my ($obj) = @_;
260a80b4 155
9a63e1f2 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')?!" );
612969fb 159
9a63e1f2 160 if ( $sector->staleness != $obj->_staleness ) {
161 return;
162 }
ea2f6d67 163
9a63e1f2 164 return $sector->get_classname;
1bf65be7 165}
166
e137c258 167sub make_reference {
168 my $self = shift;
169 my ($obj, $old_key, $new_key) = @_;
170
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')?!" );
174
175 if ( $sector->staleness != $obj->_staleness ) {
176 return;
177 }
178
179 my $old_md5 = $self->_apply_digest( $old_key );
180
181 my $value_sector = $sector->get_data_for({
182 key_md5 => $old_md5,
183 allow_head => 1,
184 });
185
186 unless ( $value_sector ) {
187 $value_sector = DBM::Deep::Engine::Sector::Null->new({
188 engine => $self,
189 data => undef,
190 });
191
192 $sector->write_data({
193 key_md5 => $old_md5,
194 key => $old_key,
195 value => $value_sector,
196 });
197 }
198
199 if ( $value_sector->isa( 'DBM::Deep::Engine::Sector::Reference' ) ) {
200 $sector->write_data({
201 key => $new_key,
202 key_md5 => $self->_apply_digest( $new_key ),
203 value => $value_sector,
204 });
205 $value_sector->increment_refcount;
206 }
207 else {
208 $sector->write_data({
209 key => $new_key,
210 key_md5 => $self->_apply_digest( $new_key ),
211 value => $value_sector->clone,
212 });
213 }
214}
215
9a63e1f2 216sub key_exists {
0d0f3d5d 217 my $self = shift;
9a63e1f2 218 my ($obj, $key) = @_;
0d0f3d5d 219
9a63e1f2 220 # This will be a Reference sector
221 my $sector = $self->_load_sector( $obj->_base_offset )
222 or return '';
0d0f3d5d 223
9a63e1f2 224 if ( $sector->staleness != $obj->_staleness ) {
225 return '';
226 }
0d0f3d5d 227
9a63e1f2 228 my $data = $sector->get_data_for({
229 key_md5 => $self->_apply_digest( $key ),
230 allow_head => 1,
231 });
20b7f047 232
9a63e1f2 233 # exists() returns 1 or '' for true/false.
234 return $data ? 1 : '';
0d0f3d5d 235}
236
9a63e1f2 237sub delete_key {
e064ccd1 238 my $self = shift;
9a63e1f2 239 my ($obj, $key) = @_;
e064ccd1 240
9a63e1f2 241 my $sector = $self->_load_sector( $obj->_base_offset )
242 or return;
460b1067 243
9a63e1f2 244 if ( $sector->staleness != $obj->_staleness ) {
245 return;
246 }
247
248 return $sector->delete_key({
249 key_md5 => $self->_apply_digest( $key ),
250 allow_head => 0,
251 });
252}
253
254sub write_value {
255 my $self = shift;
256 my ($obj, $key, $value) = @_;
257
258 my $r = Scalar::Util::reftype( $value ) || '';
259 {
260 last if $r eq '';
261 last if $r eq 'HASH';
262 last if $r eq 'ARRAY';
e064ccd1 263
9a63e1f2 264 DBM::Deep->_throw_error(
265 "Storage of references of type '$r' is not supported."
266 );
460b1067 267 }
260a80b4 268
e137c258 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." );
272
273 if ( $sector->staleness != $obj->_staleness ) {
274 DBM::Deep->_throw_error( "Cannot write to a deleted spot in DBM::Deep.n" );
275 }
276
9a63e1f2 277 my ($class, $type);
278 if ( !defined $value ) {
279 $class = 'DBM::Deep::Engine::Sector::Null';
280 }
281 elsif ( $r eq 'ARRAY' || $r eq 'HASH' ) {
e137c258 282 my $is_dbm_deep = eval { local $SIG{'__DIE__'}; $value->isa( 'DBM::Deep' ); };
283 if ( $is_dbm_deep ) {
284 if ( $value->_engine->storage == $self->storage ) {
285 my $value_sector = $self->_load_sector( $value->_base_offset );
286 $sector->write_data({
287 key => $key,
288 key_md5 => $self->_apply_digest( $key ),
289 value => $value_sector,
290 });
291 $value_sector->increment_refcount;
292 return 1;
293 }
294
295 DBM::Deep->_throw_error( "Cannot store values across DBM::Deep files. Please use export() instead." );
296 }
9a63e1f2 297 if ( $r eq 'ARRAY' && tied(@$value) ) {
298 DBM::Deep->_throw_error( "Cannot store something that is tied." );
299 }
300 if ( $r eq 'HASH' && tied(%$value) ) {
301 DBM::Deep->_throw_error( "Cannot store something that is tied." );
302 }
303 $class = 'DBM::Deep::Engine::Sector::Reference';
304 $type = substr( $r, 0, 1 );
305 }
306 else {
e137c258 307 if ( tied($value) ) {
308 DBM::Deep->_throw_error( "Cannot store something that is tied." );
309 }
9a63e1f2 310 $class = 'DBM::Deep::Engine::Sector::Scalar';
460b1067 311 }
9b2370e0 312
9a63e1f2 313 # Create this after loading the reference sector in case something bad happens.
314 # This way, we won't allocate value sector(s) needlessly.
315 my $value_sector = $class->new({
316 engine => $self,
317 data => $value,
318 type => $type,
319 });
320
321 $sector->write_data({
322 key => $key,
323 key_md5 => $self->_apply_digest( $key ),
324 value => $value_sector,
325 });
326
327 # This code is to make sure we write all the values in the $value to the disk
328 # and to make sure all changes to $value after the assignment are reflected
329 # on disk. This may be counter-intuitive at first, but it is correct dwimmery.
330 # NOTE - simply tying $value won't perform a STORE on each value. Hence, the
331 # copy to a temp value.
332 if ( $r eq 'ARRAY' ) {
333 my @temp = @$value;
334 tie @$value, 'DBM::Deep', {
335 base_offset => $value_sector->offset,
336 staleness => $value_sector->staleness,
337 storage => $self->storage,
338 engine => $self,
339 };
340 @$value = @temp;
341 bless $value, 'DBM::Deep::Array' unless Scalar::Util::blessed( $value );
e064ccd1 342 }
9a63e1f2 343 elsif ( $r eq 'HASH' ) {
344 my %temp = %$value;
345 tie %$value, 'DBM::Deep', {
346 base_offset => $value_sector->offset,
347 staleness => $value_sector->staleness,
348 storage => $self->storage,
349 engine => $self,
350 };
e064ccd1 351
9a63e1f2 352 %$value = %temp;
353 bless $value, 'DBM::Deep::Hash' unless Scalar::Util::blessed( $value );
354 }
460b1067 355
9a63e1f2 356 return 1;
e064ccd1 357}
358
9a63e1f2 359# XXX Add staleness here
360sub get_next_key {
460b1067 361 my $self = shift;
9a63e1f2 362 my ($obj, $prev_key) = @_;
70b55428 363
9a63e1f2 364 # XXX Need to add logic about resetting the iterator if any key in the reference has changed
365 unless ( $prev_key ) {
366 $obj->{iterator} = DBM::Deep::Iterator->new({
367 base_offset => $obj->_base_offset,
368 engine => $self,
369 });
370 }
118ba343 371
9a63e1f2 372 return $obj->{iterator}->get_next_key( $obj );
373}
118ba343 374
9a63e1f2 375################################################################################
260a80b4 376
9a63e1f2 377sub setup_fh {
378 my $self = shift;
379 my ($obj) = @_;
359a01ac 380
9a63e1f2 381 # We're opening the file.
382 unless ( $obj->_base_offset ) {
383 my $bytes_read = $self->_read_file_header;
118ba343 384
9a63e1f2 385 # Creating a new file
386 unless ( $bytes_read ) {
387 $self->_write_file_header;
118ba343 388
9a63e1f2 389 # 1) Create Array/Hash entry
390 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
391 engine => $self,
392 type => $obj->_type,
393 });
394 $obj->{base_offset} = $initial_reference->offset;
395 $obj->{staleness} = $initial_reference->staleness;
118ba343 396
9a63e1f2 397 $self->storage->flush;
118ba343 398 }
9a63e1f2 399 # Reading from an existing file
118ba343 400 else {
401 $obj->{base_offset} = $bytes_read;
9a63e1f2 402 my $initial_reference = DBM::Deep::Engine::Sector::Reference->new({
403 engine => $self,
404 offset => $obj->_base_offset,
405 });
406 unless ( $initial_reference ) {
407 DBM::Deep->_throw_error("Corrupted file, no master index record");
359a01ac 408 }
118ba343 409
9a63e1f2 410 unless ($obj->_type eq $initial_reference->type) {
411 DBM::Deep->_throw_error("File type mismatch");
118ba343 412 }
9a63e1f2 413
414 $obj->{staleness} = $initial_reference->staleness;
118ba343 415 }
118ba343 416 }
9a63e1f2 417
418 return 1;
419}
420
421sub begin_work {
422 my $self = shift;
423 my ($obj) = @_;
424
425 if ( $self->trans_id ) {
426 DBM::Deep->_throw_error( "Cannot begin_work within an active transaction" );
427 }
428
429 my @slots = $self->read_txn_slots;
f72b2dfb 430 my $found;
431 for my $i ( 0 .. $#slots ) {
9a63e1f2 432 next if $slots[$i];
f72b2dfb 433
9a63e1f2 434 $slots[$i] = 1;
f72b2dfb 435 $self->set_trans_id( $i + 1 );
436 $found = 1;
9a63e1f2 437 last;
438 }
f72b2dfb 439 unless ( $found ) {
440 DBM::Deep->_throw_error( "Cannot allocate transaction ID" );
441 }
9a63e1f2 442 $self->write_txn_slots( @slots );
443
444 if ( !$self->trans_id ) {
445 DBM::Deep->_throw_error( "Cannot begin_work - no available transactions" );
446 }
447
448 return;
449}
450
451sub rollback {
452 my $self = shift;
453 my ($obj) = @_;
454
455 if ( !$self->trans_id ) {
456 DBM::Deep->_throw_error( "Cannot rollback without an active transaction" );
457 }
458
459 # Each entry is the file location for a bucket that has a modification for
460 # this transaction. The entries need to be expunged.
461 foreach my $entry (@{ $self->get_entries } ) {
462 # Remove the entry here
463 my $read_loc = $entry
464 + $self->hash_size
465 + $self->byte_size
f72b2dfb 466 + $self->byte_size
467 + ($self->trans_id - 1) * ( $self->byte_size + $STALE_SIZE );
9a63e1f2 468
469 my $data_loc = $self->storage->read_at( $read_loc, $self->byte_size );
470 $data_loc = unpack( $StP{$self->byte_size}, $data_loc );
471 $self->storage->print_at( $read_loc, pack( $StP{$self->byte_size}, 0 ) );
472
473 if ( $data_loc > 1 ) {
474 $self->_load_sector( $data_loc )->free;
475 }
260a80b4 476 }
e06824f8 477
9a63e1f2 478 $self->clear_entries;
70b55428 479
9a63e1f2 480 my @slots = $self->read_txn_slots;
f72b2dfb 481 $slots[$self->trans_id-1] = 0;
9a63e1f2 482 $self->write_txn_slots( @slots );
483 $self->inc_txn_staleness_counter( $self->trans_id );
484 $self->set_trans_id( 0 );
6fde4ed2 485
70b55428 486 return 1;
487}
488
9a63e1f2 489sub commit {
16d1ad9b 490 my $self = shift;
9a63e1f2 491 my ($obj) = @_;
492
493 if ( !$self->trans_id ) {
494 DBM::Deep->_throw_error( "Cannot commit without an active transaction" );
495 }
496
497 foreach my $entry (@{ $self->get_entries } ) {
498 # Overwrite the entry in head with the entry in trans_id
499 my $base = $entry
500 + $self->hash_size
501 + $self->byte_size;
502
503 my $head_loc = $self->storage->read_at( $base, $self->byte_size );
504 $head_loc = unpack( $StP{$self->byte_size}, $head_loc );
f72b2dfb 505
506 my $spot = $base + $self->byte_size + ($self->trans_id - 1) * ( $self->byte_size + $STALE_SIZE );
9a63e1f2 507 my $trans_loc = $self->storage->read_at(
f72b2dfb 508 $spot, $self->byte_size,
9a63e1f2 509 );
510
511 $self->storage->print_at( $base, $trans_loc );
512 $self->storage->print_at(
f72b2dfb 513 $spot,
514 pack( $StP{$self->byte_size} . ' ' . $StP{$STALE_SIZE}, (0) x 2 ),
9a63e1f2 515 );
516
517 if ( $head_loc > 1 ) {
518 $self->_load_sector( $head_loc )->free;
519 }
520 }
521
522 $self->clear_entries;
523
524 my @slots = $self->read_txn_slots;
f72b2dfb 525 $slots[$self->trans_id-1] = 0;
9a63e1f2 526 $self->write_txn_slots( @slots );
527 $self->inc_txn_staleness_counter( $self->trans_id );
528 $self->set_trans_id( 0 );
529
530 return 1;
16d1ad9b 531}
532
9a63e1f2 533sub read_txn_slots {
d4b1166e 534 my $self = shift;
f72b2dfb 535 my $bl = $self->txn_bitfield_len;
536 my $num_bits = $bl * 8;
537 return split '', unpack( 'b'.$num_bits,
9a63e1f2 538 $self->storage->read_at(
f72b2dfb 539 $self->trans_loc, $bl,
9a63e1f2 540 )
541 );
542}
20f7b20c 543
9a63e1f2 544sub write_txn_slots {
545 my $self = shift;
f72b2dfb 546 my $num_bits = $self->txn_bitfield_len * 8;
9a63e1f2 547 $self->storage->print_at( $self->trans_loc,
f72b2dfb 548 pack( 'b'.$num_bits, join('', @_) ),
7dcefff3 549 );
9a63e1f2 550}
551
552sub get_running_txn_ids {
553 my $self = shift;
554 my @transactions = $self->read_txn_slots;
f72b2dfb 555 my @trans_ids = map { $_+1} grep { $transactions[$_] } 0 .. $#transactions;
9a63e1f2 556}
557
558sub get_txn_staleness_counter {
559 my $self = shift;
560 my ($trans_id) = @_;
20f7b20c 561
9a63e1f2 562 # Hardcode staleness of 0 for the HEAD
563 return 0 unless $trans_id;
f37c15ab 564
f72b2dfb 565 return unpack( $StP{$STALE_SIZE},
9a63e1f2 566 $self->storage->read_at(
90fb1a24 567 $self->trans_loc + $self->txn_bitfield_len + $STALE_SIZE * ($trans_id - 1),
568 $STALE_SIZE,
9a63e1f2 569 )
570 );
d4b1166e 571}
572
9a63e1f2 573sub inc_txn_staleness_counter {
d4b1166e 574 my $self = shift;
9a63e1f2 575 my ($trans_id) = @_;
20f7b20c 576
9a63e1f2 577 # Hardcode staleness of 0 for the HEAD
a24e7f93 578 return 0 unless $trans_id;
20f7b20c 579
9a63e1f2 580 $self->storage->print_at(
90fb1a24 581 $self->trans_loc + $self->txn_bitfield_len + $STALE_SIZE * ($trans_id - 1),
f72b2dfb 582 pack( $StP{$STALE_SIZE}, $self->get_txn_staleness_counter( $trans_id ) + 1 ),
86867f3a 583 );
9a63e1f2 584}
20f7b20c 585
9a63e1f2 586sub get_entries {
587 my $self = shift;
588 return [ keys %{ $self->{entries}{$self->trans_id} ||= {} } ];
d4b1166e 589}
590
9a63e1f2 591sub add_entry {
ea2f6d67 592 my $self = shift;
9a63e1f2 593 my ($trans_id, $loc) = @_;
ea2f6d67 594
9a63e1f2 595 $self->{entries}{$trans_id} ||= {};
596 $self->{entries}{$trans_id}{$loc} = undef;
597}
ea2f6d67 598
9a63e1f2 599# If the buckets are being relocated because of a reindexing, the entries
600# mechanism needs to be made aware of it.
601sub reindex_entry {
602 my $self = shift;
603 my ($old_loc, $new_loc) = @_;
604
605 TRANS:
606 while ( my ($trans_id, $locs) = each %{ $self->{entries} } ) {
607 foreach my $orig_loc ( keys %{ $locs } ) {
608 if ( $orig_loc == $old_loc ) {
609 delete $locs->{orig_loc};
610 $locs->{$new_loc} = undef;
611 next TRANS;
612 }
613 }
ea2f6d67 614 }
ea2f6d67 615}
616
9a63e1f2 617sub clear_entries {
d4b1166e 618 my $self = shift;
9a63e1f2 619 delete $self->{entries}{$self->trans_id};
620}
eea0d863 621
9a63e1f2 622################################################################################
eea0d863 623
9a63e1f2 624{
625 my $header_fixed = length( SIG_FILE ) + 1 + 4 + 4;
da1f1300 626 my $this_file_version = 3;
9a63e1f2 627
628 sub _write_file_header {
629 my $self = shift;
630
f72b2dfb 631 my $nt = $self->num_txns;
632 my $bl = $self->txn_bitfield_len;
633
634 my $header_var = 1 + 1 + 1 + 1 + $bl + $STALE_SIZE * ($nt - 1) + 3 * $self->byte_size;
9a63e1f2 635
636 my $loc = $self->storage->request_space( $header_fixed + $header_var );
637
638 $self->storage->print_at( $loc,
639 SIG_FILE,
640 SIG_HEADER,
f72b2dfb 641 pack('N', $this_file_version), # At this point, we're at 9 bytes
642 pack('N', $header_var), # header size
9a63e1f2 643 # --- Above is $header_fixed. Below is $header_var
644 pack('C', $self->byte_size),
f72b2dfb 645
646 # These shenanigans are to allow a 256 within a C
647 pack('C', $self->max_buckets - 1),
648 pack('C', $self->data_sector_size - 1),
649
650 pack('C', $nt),
651 pack('C' . $bl, 0 ), # Transaction activeness bitfield
652 pack($StP{$STALE_SIZE}.($nt-1), 0 x ($nt-1) ), # Transaction staleness counters
9a63e1f2 653 pack($StP{$self->byte_size}, 0), # Start of free chain (blist size)
654 pack($StP{$self->byte_size}, 0), # Start of free chain (data size)
655 pack($StP{$self->byte_size}, 0), # Start of free chain (index size)
eea0d863 656 );
eea0d863 657
f72b2dfb 658 #XXX Set these less fragilely
659 $self->set_trans_loc( $header_fixed + 4 );
660 $self->set_chains_loc( $header_fixed + 4 + $bl + $STALE_SIZE * ($nt-1) );
20f7b20c 661
9a63e1f2 662 return;
c9b6d0d8 663 }
75be6413 664
9a63e1f2 665 sub _read_file_header {
666 my $self = shift;
ea2f6d67 667
9a63e1f2 668 my $buffer = $self->storage->read_at( 0, $header_fixed );
669 return unless length($buffer);
019404df 670
f72b2dfb 671 my ($file_signature, $sig_header, $file_version, $size) = unpack(
9a63e1f2 672 'A4 A N N', $buffer
673 );
ea2f6d67 674
9a63e1f2 675 unless ( $file_signature eq SIG_FILE ) {
676 $self->storage->close;
677 DBM::Deep->_throw_error( "Signature not found -- file is not a Deep DB" );
678 }
ea2f6d67 679
9a63e1f2 680 unless ( $sig_header eq SIG_HEADER ) {
681 $self->storage->close;
f72b2dfb 682 DBM::Deep->_throw_error( "Pre-1.00 file version found" );
683 }
684
685 unless ( $file_version == $this_file_version ) {
686 $self->storage->close;
687 DBM::Deep->_throw_error(
688 "Wrong file version found - " . $file_version .
689 " - expected " . $this_file_version
690 );
75be6413 691 }
504185fb 692
9a63e1f2 693 my $buffer2 = $self->storage->read_at( undef, $size );
f72b2dfb 694 my @values = unpack( 'C C C C', $buffer2 );
386bab6c 695
f72b2dfb 696 if ( @values != 4 || grep { !defined } @values ) {
9a63e1f2 697 $self->storage->close;
698 DBM::Deep->_throw_error("Corrupted file - bad header");
ea2f6d67 699 }
700
9a63e1f2 701 #XXX Add warnings if values weren't set right
f72b2dfb 702 @{$self}{qw(byte_size max_buckets data_sector_size num_txns)} = @values;
ea2f6d67 703
f72b2dfb 704 # These shenangians are to allow a 256 within a C
705 $self->{max_buckets} += 1;
706 $self->{data_sector_size} += 1;
707
708 my $bl = $self->txn_bitfield_len;
709
710 my $header_var = scalar(@values) + $bl + $STALE_SIZE * ($self->num_txns - 1) + 3 * $self->byte_size;
9a63e1f2 711 unless ( $size == $header_var ) {
712 $self->storage->close;
713 DBM::Deep->_throw_error( "Unexpected size found ($size <-> $header_var)." );
c9b6d0d8 714 }
20f7b20c 715
f72b2dfb 716 $self->set_trans_loc( $header_fixed + scalar(@values) );
717 $self->set_chains_loc( $header_fixed + scalar(@values) + $bl + $STALE_SIZE * ($self->num_txns - 1) );
718
9a63e1f2 719 return length($buffer) + length($buffer2);
720 }
d5d7c51d 721}
722
9a63e1f2 723sub _load_sector {
d5d7c51d 724 my $self = shift;
9a63e1f2 725 my ($offset) = @_;
d5d7c51d 726
9a63e1f2 727 # Add a catch for offset of 0 or 1
728 return if $offset <= 1;
d5d7c51d 729
9a63e1f2 730 my $type = $self->storage->read_at( $offset, 1 );
731 return if $type eq chr(0);
d5d7c51d 732
9a63e1f2 733 if ( $type eq $self->SIG_ARRAY || $type eq $self->SIG_HASH ) {
734 return DBM::Deep::Engine::Sector::Reference->new({
735 engine => $self,
736 type => $type,
737 offset => $offset,
738 });
f37c15ab 739 }
9a63e1f2 740 # XXX Don't we need key_md5 here?
741 elsif ( $type eq $self->SIG_BLIST ) {
742 return DBM::Deep::Engine::Sector::BucketList->new({
743 engine => $self,
744 type => $type,
745 offset => $offset,
746 });
d5d7c51d 747 }
9a63e1f2 748 elsif ( $type eq $self->SIG_INDEX ) {
749 return DBM::Deep::Engine::Sector::Index->new({
750 engine => $self,
751 type => $type,
752 offset => $offset,
753 });
d5d7c51d 754 }
9a63e1f2 755 elsif ( $type eq $self->SIG_NULL ) {
756 return DBM::Deep::Engine::Sector::Null->new({
757 engine => $self,
758 type => $type,
759 offset => $offset,
760 });
d5d7c51d 761 }
9a63e1f2 762 elsif ( $type eq $self->SIG_DATA ) {
763 return DBM::Deep::Engine::Sector::Scalar->new({
764 engine => $self,
765 type => $type,
766 offset => $offset,
767 });
9d4fa373 768 }
9a63e1f2 769 # This was deleted from under us, so just return and let the caller figure it out.
770 elsif ( $type eq $self->SIG_FREE ) {
771 return;
20f7b20c 772 }
d4b1166e 773
9a63e1f2 774 DBM::Deep->_throw_error( "'$offset': Don't know what to do with type '$type'" );
d4b1166e 775}
776
9a63e1f2 777sub _apply_digest {
75be6413 778 my $self = shift;
9a63e1f2 779 return $self->{digest}->(@_);
780}
16d1ad9b 781
9a63e1f2 782sub _add_free_blist_sector { shift->_add_free_sector( 0, @_ ) }
783sub _add_free_data_sector { shift->_add_free_sector( 1, @_ ) }
784sub _add_free_index_sector { shift->_add_free_sector( 2, @_ ) }
75be6413 785
9a63e1f2 786sub _add_free_sector {
787 my $self = shift;
788 my ($multiple, $offset, $size) = @_;
75be6413 789
9a63e1f2 790 my $chains_offset = $multiple * $self->byte_size;
75be6413 791
9a63e1f2 792 my $storage = $self->storage;
75be6413 793
9a63e1f2 794 # Increment staleness.
795 # XXX Can this increment+modulo be done by "&= 0x1" ?
f72b2dfb 796 my $staleness = unpack( $StP{$STALE_SIZE}, $storage->read_at( $offset + SIG_SIZE, $STALE_SIZE ) );
797 $staleness = ($staleness + 1 ) % ( 2 ** ( 8 * $STALE_SIZE ) );
798 $storage->print_at( $offset + SIG_SIZE, pack( $StP{$STALE_SIZE}, $staleness ) );
75be6413 799
9a63e1f2 800 my $old_head = $storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
75be6413 801
9a63e1f2 802 $storage->print_at( $self->chains_loc + $chains_offset,
803 pack( $StP{$self->byte_size}, $offset ),
804 );
75be6413 805
9a63e1f2 806 # Record the old head in the new sector after the signature and staleness counter
f72b2dfb 807 $storage->print_at( $offset + SIG_SIZE + $STALE_SIZE, $old_head );
9a63e1f2 808}
75be6413 809
9a63e1f2 810sub _request_blist_sector { shift->_request_sector( 0, @_ ) }
811sub _request_data_sector { shift->_request_sector( 1, @_ ) }
812sub _request_index_sector { shift->_request_sector( 2, @_ ) }
7b1e1aa1 813
9a63e1f2 814sub _request_sector {
815 my $self = shift;
816 my ($multiple, $size) = @_;
75be6413 817
9a63e1f2 818 my $chains_offset = $multiple * $self->byte_size;
2603d86e 819
9a63e1f2 820 my $old_head = $self->storage->read_at( $self->chains_loc + $chains_offset, $self->byte_size );
821 my $loc = unpack( $StP{$self->byte_size}, $old_head );
75be6413 822
9a63e1f2 823 # We don't have any free sectors of the right size, so allocate a new one.
824 unless ( $loc ) {
825 my $offset = $self->storage->request_space( $size );
7b1e1aa1 826
9a63e1f2 827 # Zero out the new sector. This also guarantees correct increases
828 # in the filesize.
829 $self->storage->print_at( $offset, chr(0) x $size );
7b1e1aa1 830
9a63e1f2 831 return $offset;
7b1e1aa1 832 }
833
9a63e1f2 834 # Read the new head after the signature and the staleness counter
f72b2dfb 835 my $new_head = $self->storage->read_at( $loc + SIG_SIZE + $STALE_SIZE, $self->byte_size );
9a63e1f2 836 $self->storage->print_at( $self->chains_loc + $chains_offset, $new_head );
837 $self->storage->print_at(
f72b2dfb 838 $loc + SIG_SIZE + $STALE_SIZE,
9a63e1f2 839 pack( $StP{$self->byte_size}, 0 ),
7b1e1aa1 840 );
75be6413 841
9a63e1f2 842 return $loc;
75be6413 843}
844
9a63e1f2 845################################################################################
8db25060 846
9a63e1f2 847sub storage { $_[0]{storage} }
848sub byte_size { $_[0]{byte_size} }
849sub hash_size { $_[0]{hash_size} }
850sub hash_chars { $_[0]{hash_chars} }
851sub num_txns { $_[0]{num_txns} }
852sub max_buckets { $_[0]{max_buckets} }
853sub blank_md5 { chr(0) x $_[0]->hash_size }
f72b2dfb 854sub data_sector_size { $_[0]{data_sector_size} }
855
856# This is a calculated value
857sub txn_bitfield_len {
858 my $self = shift;
859 unless ( exists $self->{txn_bitfield_len} ) {
860 my $temp = ($self->num_txns) / 8;
861 if ( $temp > int( $temp ) ) {
862 $temp = int( $temp ) + 1;
863 }
864 $self->{txn_bitfield_len} = $temp;
865 }
866 return $self->{txn_bitfield_len};
867}
8db25060 868
9a63e1f2 869sub trans_id { $_[0]{trans_id} }
870sub set_trans_id { $_[0]{trans_id} = $_[1] }
8db25060 871
9a63e1f2 872sub trans_loc { $_[0]{trans_loc} }
873sub set_trans_loc { $_[0]{trans_loc} = $_[1] }
874
875sub chains_loc { $_[0]{chains_loc} }
876sub set_chains_loc { $_[0]{chains_loc} = $_[1] }
877
9f83dc31 878sub _dump_file {
879 my $self = shift;
880
881 # Read the header
882 my $spot = $self->_read_file_header();
883
884 my %types = (
885 0 => 'B',
886 1 => 'D',
887 2 => 'I',
888 );
889
890 my %sizes = (
891 'D' => $self->data_sector_size,
990141bb 892 'B' => DBM::Deep::Engine::Sector::BucketList->new({engine=>$self,offset=>1})->size,
893 'I' => DBM::Deep::Engine::Sector::Index->new({engine=>$self,offset=>1})->size,
9f83dc31 894 );
895
90fb1a24 896 my $return = "";
9f83dc31 897 # Read the free sector chains
898 my %sectors;
899 foreach my $multiple ( 0 .. 2 ) {
90fb1a24 900 $return .= "Chains($types{$multiple}):";
901 my $old_loc = $self->chains_loc + $multiple * $self->byte_size;
9f83dc31 902 while ( 1 ) {
903 my $loc = unpack(
904 $StP{$self->byte_size},
905 $self->storage->read_at( $old_loc, $self->byte_size ),
906 );
907
908 # We're now out of free sectors of this kind.
909 unless ( $loc ) {
910 last;
911 }
912
913 $sectors{ $types{$multiple} }{ $loc } = undef;
914 $old_loc = $loc + SIG_SIZE + $STALE_SIZE;
90fb1a24 915 $return .= " $loc";
9f83dc31 916 }
90fb1a24 917 $return .= $/;
9f83dc31 918 }
919
9f83dc31 920 SECTOR:
921 while ( $spot < $self->storage->{end} ) {
922 # Read each sector in order.
923 my $sector = $self->_load_sector( $spot );
924 if ( !$sector ) {
925 # Find it in the free-sectors that were found already
926 foreach my $type ( keys %sectors ) {
927 if ( exists $sectors{$type}{$spot} ) {
928 my $size = $sizes{$type};
929 $return .= sprintf "%08d: %s %04d\n", $spot, 'F' . $type, $size;
930 $spot += $size;
931 next SECTOR;
932 }
933 }
934
90fb1a24 935 die "********\n$return\nDidn't find free sector for $spot in chains\n********\n";
9f83dc31 936 }
937 else {
938 $return .= sprintf "%08d: %s %04d", $spot, $sector->type, $sector->size;
939 if ( $sector->type eq 'D' ) {
940 $return .= ' ' . $sector->data;
941 }
942 elsif ( $sector->type eq 'A' || $sector->type eq 'H' ) {
943 $return .= ' REF: ' . $sector->get_refcount;
944 }
945 elsif ( $sector->type eq 'B' ) {
946 foreach my $bucket ( $sector->chopped_up ) {
947 $return .= "\n ";
a24e7f93 948 $return .= sprintf "%08d", unpack($StP{$self->byte_size},
9f83dc31 949 substr( $bucket->[-1], $self->hash_size, $self->byte_size),
950 );
951 foreach my $txn ( 0 .. $self->num_txns - 1 ) {
952 my $l = unpack( $StP{$self->byte_size},
953 substr( $bucket->[-1],
954 $self->hash_size + $self->byte_size + $txn * ($self->byte_size + $STALE_SIZE),
955 $self->byte_size,
956 ),
957 );
a24e7f93 958 $return .= sprintf " %08d", $l;
9f83dc31 959 }
960 }
961 }
962 $return .= $/;
963
964 $spot += $sector->size;
965 }
966 }
967
968 return $return;
969}
970
9a63e1f2 971################################################################################
972
973package DBM::Deep::Iterator;
974
975sub new {
976 my $class = shift;
977 my ($args) = @_;
978
979 my $self = bless {
980 breadcrumbs => [],
981 engine => $args->{engine},
982 base_offset => $args->{base_offset},
983 }, $class;
984
985 Scalar::Util::weaken( $self->{engine} );
986
987 return $self;
988}
989
990sub reset { $_[0]{breadcrumbs} = [] }
991
992sub get_sector_iterator {
993 my $self = shift;
994 my ($loc) = @_;
995
996 my $sector = $self->{engine}->_load_sector( $loc )
997 or return;
998
999 if ( $sector->isa( 'DBM::Deep::Engine::Sector::Index' ) ) {
1000 return DBM::Deep::Iterator::Index->new({
1001 iterator => $self,
1002 sector => $sector,
685e40f1 1003 });
9a63e1f2 1004 }
1005 elsif ( $sector->isa( 'DBM::Deep::Engine::Sector::BucketList' ) ) {
1006 return DBM::Deep::Iterator::BucketList->new({
1007 iterator => $self,
1008 sector => $sector,
1009 });
1010 }
8db25060 1011
9a63e1f2 1012 DBM::Deep->_throw_error( "get_sector_iterator(): Why did $loc make a $sector?" );
1013}
1014
1015sub get_next_key {
1016 my $self = shift;
1017 my ($obj) = @_;
1018
1019 my $crumbs = $self->{breadcrumbs};
1020 my $e = $self->{engine};
1021
1022 unless ( @$crumbs ) {
1023 # This will be a Reference sector
1024 my $sector = $e->_load_sector( $self->{base_offset} )
1025 # If no sector is found, thist must have been deleted from under us.
1026 or return;
1027
1028 if ( $sector->staleness != $obj->_staleness ) {
1029 return;
8db25060 1030 }
1031
9a63e1f2 1032 my $loc = $sector->get_blist_loc
1033 or return;
1034
1035 push @$crumbs, $self->get_sector_iterator( $loc );
8db25060 1036 }
8db25060 1037
9a63e1f2 1038 FIND_NEXT_KEY: {
1039 # We're at the end.
1040 unless ( @$crumbs ) {
1041 $self->reset;
8db25060 1042 return;
1043 }
8db25060 1044
9a63e1f2 1045 my $iterator = $crumbs->[-1];
1046
1047 # This level is done.
1048 if ( $iterator->at_end ) {
1049 pop @$crumbs;
1050 redo FIND_NEXT_KEY;
1051 }
1052
1053 if ( $iterator->isa( 'DBM::Deep::Iterator::Index' ) ) {
1054 # If we don't have any more, it will be caught at the
1055 # prior check.
1056 if ( my $next = $iterator->get_next_iterator ) {
1057 push @$crumbs, $next;
1058 }
1059 redo FIND_NEXT_KEY;
1060 }
1061
1062 unless ( $iterator->isa( 'DBM::Deep::Iterator::BucketList' ) ) {
1063 DBM::Deep->_throw_error(
1064 "Should have a bucketlist iterator here - instead have $iterator"
1065 );
1066 }
1067
1068 # At this point, we have a BucketList iterator
1069 my $key = $iterator->get_next_key;
1070 if ( defined $key ) {
1071 return $key;
1072 }
1073 #XXX else { $iterator->set_to_end() } ?
1074
1075 # We hit the end of the bucketlist iterator, so redo
1076 redo FIND_NEXT_KEY;
8db25060 1077 }
1078
9a63e1f2 1079 DBM::Deep->_throw_error( "get_next_key(): How did we get here?" );
8db25060 1080}
1081
9a63e1f2 1082package DBM::Deep::Iterator::Index;
1083
1084sub new {
1085 my $self = bless $_[1] => $_[0];
1086 $self->{curr_index} = 0;
1087 return $self;
1088}
1089
1090sub at_end {
beac1dff 1091 my $self = shift;
9a63e1f2 1092 return $self->{curr_index} >= $self->{iterator}{engine}->hash_chars;
1093}
9020ee8c 1094
9a63e1f2 1095sub get_next_iterator {
1096 my $self = shift;
94e8af14 1097
9a63e1f2 1098 my $loc;
1099 while ( !$loc ) {
1100 return if $self->at_end;
1101 $loc = $self->{sector}->get_entry( $self->{curr_index}++ );
386bab6c 1102 }
94e8af14 1103
9a63e1f2 1104 return $self->{iterator}->get_sector_iterator( $loc );
1105}
1106
1107package DBM::Deep::Iterator::BucketList;
1108
1109sub new {
1110 my $self = bless $_[1] => $_[0];
1111 $self->{curr_index} = 0;
1112 return $self;
1113}
1114
1115sub at_end {
1116 my $self = shift;
1117 return $self->{curr_index} >= $self->{iterator}{engine}->max_buckets;
1118}
1119
1120sub get_next_key {
1121 my $self = shift;
1122
1123 return if $self->at_end;
1124
1125 my $idx = $self->{curr_index}++;
1126
1127 my $data_loc = $self->{sector}->get_data_location_for({
1128 allow_head => 1,
1129 idx => $idx,
1130 }) or return;
1131
1132 #XXX Do we want to add corruption checks here?
1133 return $self->{sector}->get_key_for( $idx )->data;
1134}
1135
1136package DBM::Deep::Engine::Sector;
1137
1138sub new {
1139 my $self = bless $_[1], $_[0];
1140 Scalar::Util::weaken( $self->{engine} );
1141 $self->_init;
1142 return $self;
1143}
1144
1145#sub _init {}
1146#sub clone { DBM::Deep->_throw_error( "Must be implemented in the child class" ); }
1147
1148sub engine { $_[0]{engine} }
1149sub offset { $_[0]{offset} }
1150sub type { $_[0]{type} }
1151
1152sub base_size {
1153 my $self = shift;
f72b2dfb 1154 return $self->engine->SIG_SIZE + $STALE_SIZE;
9a63e1f2 1155}
1156
1157sub free {
1158 my $self = shift;
1159
1160 my $e = $self->engine;
1161
1162 $e->storage->print_at( $self->offset, $e->SIG_FREE );
1163 # Skip staleness counter
1164 $e->storage->print_at( $self->offset + $self->base_size,
1165 chr(0) x ($self->size - $self->base_size),
1166 );
1167
1168 my $free_meth = $self->free_meth;
1169 $e->$free_meth( $self->offset, $self->size );
1170
beac1dff 1171 return;
9020ee8c 1172}
ab0e4957 1173
9a63e1f2 1174package DBM::Deep::Engine::Sector::Data;
1175
1176our @ISA = qw( DBM::Deep::Engine::Sector );
1177
1178# This is in bytes
f72b2dfb 1179sub size { $_[0]{engine}->data_sector_size }
9a63e1f2 1180sub free_meth { return '_add_free_data_sector' }
1181
1182sub clone {
beac1dff 1183 my $self = shift;
9a63e1f2 1184 return ref($self)->new({
1185 engine => $self->engine,
9a63e1f2 1186 type => $self->type,
f72b2dfb 1187 data => $self->data,
9a63e1f2 1188 });
1189}
1190
1191package DBM::Deep::Engine::Sector::Scalar;
1192
1193our @ISA = qw( DBM::Deep::Engine::Sector::Data );
ab0e4957 1194
9a63e1f2 1195sub free {
1196 my $self = shift;
633df1fd 1197
9a63e1f2 1198 my $chain_loc = $self->chain_loc;
633df1fd 1199
9a63e1f2 1200 $self->SUPER::free();
633df1fd 1201
9a63e1f2 1202 if ( $chain_loc ) {
1203 $self->engine->_load_sector( $chain_loc )->free;
633df1fd 1204 }
1205
9a63e1f2 1206 return;
1207}
1208
1209sub type { $_[0]{engine}->SIG_DATA }
1210sub _init {
1211 my $self = shift;
1212
1213 my $engine = $self->engine;
1214
1215 unless ( $self->offset ) {
f72b2dfb 1216 my $data_section = $self->size - $self->base_size - $engine->byte_size - 1;
7a960a12 1217
9a63e1f2 1218 $self->{offset} = $engine->_request_data_sector( $self->size );
7a960a12 1219
9a63e1f2 1220 my $data = delete $self->{data};
1221 my $dlen = length $data;
1222 my $continue = 1;
1223 my $curr_offset = $self->offset;
1224 while ( $continue ) {
633df1fd 1225
9a63e1f2 1226 my $next_offset = 0;
1227
1228 my ($leftover, $this_len, $chunk);
1229 if ( $dlen > $data_section ) {
1230 $leftover = 0;
1231 $this_len = $data_section;
1232 $chunk = substr( $data, 0, $this_len );
1233
1234 $dlen -= $data_section;
1235 $next_offset = $engine->_request_data_sector( $self->size );
1236 $data = substr( $data, $this_len );
1237 }
1238 else {
1239 $leftover = $data_section - $dlen;
1240 $this_len = $dlen;
1241 $chunk = $data;
ea2f6d67 1242
9a63e1f2 1243 $continue = 0;
ea2f6d67 1244 }
9a63e1f2 1245
1246 $engine->storage->print_at( $curr_offset, $self->type ); # Sector type
1247 # Skip staleness
1248 $engine->storage->print_at( $curr_offset + $self->base_size,
1249 pack( $StP{$engine->byte_size}, $next_offset ), # Chain loc
1250 pack( $StP{1}, $this_len ), # Data length
1251 $chunk, # Data to be stored in this sector
1252 chr(0) x $leftover, # Zero-fill the rest
1253 );
1254
1255 $curr_offset = $next_offset;
633df1fd 1256 }
1257
9a63e1f2 1258 return;
386bab6c 1259 }
9a63e1f2 1260}
7a960a12 1261
9a63e1f2 1262sub data_length {
1263 my $self = shift;
7a960a12 1264
9a63e1f2 1265 my $buffer = $self->engine->storage->read_at(
1266 $self->offset + $self->base_size + $self->engine->byte_size, 1
1267 );
633df1fd 1268
9a63e1f2 1269 return unpack( $StP{1}, $buffer );
ab0e4957 1270}
1271
9a63e1f2 1272sub chain_loc {
beac1dff 1273 my $self = shift;
9a63e1f2 1274 return unpack(
1275 $StP{$self->engine->byte_size},
1276 $self->engine->storage->read_at(
1277 $self->offset + $self->base_size,
1278 $self->engine->byte_size,
1279 ),
1280 );
1281}
912d50b1 1282
9a63e1f2 1283sub data {
1284 my $self = shift;
1285
1286 my $data;
1287 while ( 1 ) {
1288 my $chain_loc = $self->chain_loc;
1289
1290 $data .= $self->engine->storage->read_at(
1291 $self->offset + $self->base_size + $self->engine->byte_size + 1, $self->data_length,
1292 );
1293
1294 last unless $chain_loc;
1295
1296 $self = $self->engine->_load_sector( $chain_loc );
ea2f6d67 1297 }
9a63e1f2 1298
1299 return $data;
912d50b1 1300}
1301
9a63e1f2 1302package DBM::Deep::Engine::Sector::Null;
1303
1304our @ISA = qw( DBM::Deep::Engine::Sector::Data );
1305
1306sub type { $_[0]{engine}->SIG_NULL }
1307sub data_length { 0 }
1308sub data { return }
1309
1310sub _init {
beac1dff 1311 my $self = shift;
d0b74c17 1312
9a63e1f2 1313 my $engine = $self->engine;
d0b74c17 1314
9a63e1f2 1315 unless ( $self->offset ) {
1316 my $leftover = $self->size - $self->base_size - 1 * $engine->byte_size - 1;
d0b74c17 1317
9a63e1f2 1318 $self->{offset} = $engine->_request_data_sector( $self->size );
1319 $engine->storage->print_at( $self->offset, $self->type ); # Sector type
1320 # Skip staleness counter
1321 $engine->storage->print_at( $self->offset + $self->base_size,
1322 pack( $StP{$engine->byte_size}, 0 ), # Chain loc
1323 pack( $StP{1}, $self->data_length ), # Data length
1324 chr(0) x $leftover, # Zero-fill the rest
1325 );
d0b74c17 1326
9a63e1f2 1327 return;
1328 }
1329}
d0b74c17 1330
9a63e1f2 1331package DBM::Deep::Engine::Sector::Reference;
16d1ad9b 1332
9a63e1f2 1333our @ISA = qw( DBM::Deep::Engine::Sector::Data );
d0b74c17 1334
9a63e1f2 1335sub _init {
1336 my $self = shift;
d5d7c51d 1337
9a63e1f2 1338 my $e = $self->engine;
d5d7c51d 1339
9a63e1f2 1340 unless ( $self->offset ) {
1341 my $classname = Scalar::Util::blessed( delete $self->{data} );
e137c258 1342 my $leftover = $self->size - $self->base_size - 3 * $e->byte_size;
9a63e1f2 1343
1344 my $class_offset = 0;
1345 if ( defined $classname ) {
1346 my $class_sector = DBM::Deep::Engine::Sector::Scalar->new({
1347 engine => $e,
1348 data => $classname,
1349 });
1350 $class_offset = $class_sector->offset;
d0b74c17 1351 }
1352
9a63e1f2 1353 $self->{offset} = $e->_request_data_sector( $self->size );
1354 $e->storage->print_at( $self->offset, $self->type ); # Sector type
1355 # Skip staleness counter
1356 $e->storage->print_at( $self->offset + $self->base_size,
1357 pack( $StP{$e->byte_size}, 0 ), # Index/BList loc
1358 pack( $StP{$e->byte_size}, $class_offset ), # Classname loc
e137c258 1359 pack( $StP{$e->byte_size}, 1 ), # Initial refcount
9a63e1f2 1360 chr(0) x $leftover, # Zero-fill the rest
1361 );
1362 }
1363 else {
1364 $self->{type} = $e->storage->read_at( $self->offset, 1 );
beac1dff 1365 }
d0b74c17 1366
9a63e1f2 1367 $self->{staleness} = unpack(
f72b2dfb 1368 $StP{$STALE_SIZE},
1369 $e->storage->read_at( $self->offset + $e->SIG_SIZE, $STALE_SIZE ),
9a63e1f2 1370 );
1371
1372 return;
6736c116 1373}
1374
9a63e1f2 1375sub free {
d0b74c17 1376 my $self = shift;
d0b74c17 1377
e137c258 1378 # We're not ready to be removed yet.
1379 if ( $self->decrement_refcount > 0 ) {
1380 return;
1381 }
1382
9a63e1f2 1383 my $blist_loc = $self->get_blist_loc;
1384 $self->engine->_load_sector( $blist_loc )->free if $blist_loc;
d0b74c17 1385
9a63e1f2 1386 my $class_loc = $self->get_class_offset;
1387 $self->engine->_load_sector( $class_loc )->free if $class_loc;
d0b74c17 1388
9a63e1f2 1389 $self->SUPER::free();
d0b74c17 1390}
1391
9a63e1f2 1392sub staleness { $_[0]{staleness} }
1393
1394sub get_data_for {
6736c116 1395 my $self = shift;
9a63e1f2 1396 my ($args) = @_;
d0b74c17 1397
9a63e1f2 1398 # Assume that the head is not allowed unless otherwise specified.
1399 $args->{allow_head} = 0 unless exists $args->{allow_head};
6736c116 1400
9a63e1f2 1401 # Assume we don't create a new blist location unless otherwise specified.
1402 $args->{create} = 0 unless exists $args->{create};
d0b74c17 1403
9a63e1f2 1404 my $blist = $self->get_bucket_list({
1405 key_md5 => $args->{key_md5},
1406 key => $args->{key},
1407 create => $args->{create},
1408 });
1409 return unless $blist && $blist->{found};
e5fc7e69 1410
9a63e1f2 1411 # At this point, $blist knows where the md5 is. What it -doesn't- know yet
1412 # is whether or not this transaction has this key. That's part of the next
1413 # function call.
1414 my $location = $blist->get_data_location_for({
1415 allow_head => $args->{allow_head},
1416 }) or return;
e5fc7e69 1417
9a63e1f2 1418 return $self->engine->_load_sector( $location );
1419}
d0b74c17 1420
9a63e1f2 1421sub write_data {
1422 my $self = shift;
1423 my ($args) = @_;
1424
1425 my $blist = $self->get_bucket_list({
1426 key_md5 => $args->{key_md5},
1427 key => $args->{key},
1428 create => 1,
1429 }) or DBM::Deep->_throw_error( "How did write_data fail (no blist)?!" );
1430
1431 # Handle any transactional bookkeeping.
1432 if ( $self->engine->trans_id ) {
1433 if ( ! $blist->has_md5 ) {
1434 $blist->mark_deleted({
1435 trans_id => 0,
1436 });
1437 }
42717e46 1438 }
e5fc7e69 1439 else {
9a63e1f2 1440 my @trans_ids = $self->engine->get_running_txn_ids;
1441 if ( $blist->has_md5 ) {
1442 if ( @trans_ids ) {
1443 my $old_value = $blist->get_data_for;
1444 foreach my $other_trans_id ( @trans_ids ) {
1445 next if $blist->get_data_location_for({
1446 trans_id => $other_trans_id,
1447 allow_head => 0,
1448 });
1449 $blist->write_md5({
1450 trans_id => $other_trans_id,
1451 key => $args->{key},
1452 key_md5 => $args->{key_md5},
1453 value => $old_value->clone,
1454 });
1455 }
beac1dff 1456 }
9a63e1f2 1457 }
1458 else {
1459 if ( @trans_ids ) {
1460 foreach my $other_trans_id ( @trans_ids ) {
1461 #XXX This doesn't seem to possible to ever happen . . .
1462 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1463 $blist->mark_deleted({
1464 trans_id => $other_trans_id,
1465 });
ea2f6d67 1466 }
9a63e1f2 1467 }
1468 }
1469 }
ea2f6d67 1470
9a63e1f2 1471 #XXX Is this safe to do transactionally?
1472 # Free the place we're about to write to.
1473 if ( $blist->get_data_location_for({ allow_head => 0 }) ) {
1474 $blist->get_data_for({ allow_head => 0 })->free;
1475 }
8db25060 1476
9a63e1f2 1477 $blist->write_md5({
1478 key => $args->{key},
1479 key_md5 => $args->{key_md5},
1480 value => $args->{value},
1481 });
1482}
d0b74c17 1483
9a63e1f2 1484sub delete_key {
1485 my $self = shift;
1486 my ($args) = @_;
86867f3a 1487
9a63e1f2 1488 # XXX What should happen if this fails?
1489 my $blist = $self->get_bucket_list({
1490 key_md5 => $args->{key_md5},
1491 }) or DBM::Deep->_throw_error( "How did delete_key fail (no blist)?!" );
1492
1493 # Save the location so that we can free the data
1494 my $location = $blist->get_data_location_for({
1495 allow_head => 0,
1496 });
1497 my $old_value = $location && $self->engine->_load_sector( $location );
1498
1499 my @trans_ids = $self->engine->get_running_txn_ids;
1500
90fb1a24 1501 # If we're the HEAD and there are running txns, then we need to clone this value to the other
1502 # transactions to preserve Isolation.
9a63e1f2 1503 if ( $self->engine->trans_id == 0 ) {
1504 if ( @trans_ids ) {
1505 foreach my $other_trans_id ( @trans_ids ) {
1506 next if $blist->get_data_location_for({ trans_id => $other_trans_id, allow_head => 0 });
1507 $blist->write_md5({
1508 trans_id => $other_trans_id,
1509 key => $args->{key},
1510 key_md5 => $args->{key_md5},
1511 value => $old_value->clone,
1512 });
beac1dff 1513 }
8db25060 1514 }
9a63e1f2 1515 }
d0b74c17 1516
9a63e1f2 1517 my $data;
1518 if ( @trans_ids ) {
1519 $blist->mark_deleted( $args );
1520
1521 if ( $old_value ) {
1522 $data = $old_value->data;
1523 $old_value->free;
1524 }
1525 }
1526 else {
1527 $data = $blist->delete_md5( $args );
42717e46 1528 }
d0b74c17 1529
9a63e1f2 1530 return $data;
6736c116 1531}
1532
9a63e1f2 1533sub get_blist_loc {
1534 my $self = shift;
75be6413 1535
9a63e1f2 1536 my $e = $self->engine;
1537 my $blist_loc = $e->storage->read_at( $self->offset + $self->base_size, $e->byte_size );
1538 return unpack( $StP{$e->byte_size}, $blist_loc );
1539}
1540
1541sub get_bucket_list {
75be6413 1542 my $self = shift;
9a63e1f2 1543 my ($args) = @_;
1544 $args ||= {};
1545
1546 # XXX Add in check here for recycling?
1547
1548 my $engine = $self->engine;
1549
1550 my $blist_loc = $self->get_blist_loc;
1551
1552 # There's no index or blist yet
1553 unless ( $blist_loc ) {
1554 return unless $args->{create};
1555
1556 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1557 engine => $engine,
1558 key_md5 => $args->{key_md5},
1559 });
1560
1561 $engine->storage->print_at( $self->offset + $self->base_size,
1562 pack( $StP{$engine->byte_size}, $blist->offset ),
1563 );
1564
1565 return $blist;
1566 }
1567
1568 my $sector = $engine->_load_sector( $blist_loc )
1569 or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
1570 my $i = 0;
1571 my $last_sector = undef;
1572 while ( $sector->isa( 'DBM::Deep::Engine::Sector::Index' ) ) {
1573 $blist_loc = $sector->get_entry( ord( substr( $args->{key_md5}, $i++, 1 ) ) );
1574 $last_sector = $sector;
1575 if ( $blist_loc ) {
1576 $sector = $engine->_load_sector( $blist_loc )
1577 or DBM::Deep->_throw_error( "Cannot read sector at $blist_loc in get_bucket_list()" );
1578 }
1579 else {
1580 $sector = undef;
1581 last;
1582 }
1583 }
1584
1585 # This means we went through the Index sector(s) and found an empty slot
1586 unless ( $sector ) {
1587 return unless $args->{create};
1588
1589 DBM::Deep->_throw_error( "No last_sector when attempting to build a new entry" )
1590 unless $last_sector;
1591
1592 my $blist = DBM::Deep::Engine::Sector::BucketList->new({
1593 engine => $engine,
1594 key_md5 => $args->{key_md5},
1595 });
1596
1597 $last_sector->set_entry( ord( substr( $args->{key_md5}, $i - 1, 1 ) ) => $blist->offset );
1598
1599 return $blist;
1600 }
75be6413 1601
9a63e1f2 1602 $sector->find_md5( $args->{key_md5} );
1603
1604 # See whether or not we need to reindex the bucketlist
1605 if ( !$sector->has_md5 && $args->{create} && $sector->{idx} == -1 ) {
1606 my $new_index = DBM::Deep::Engine::Sector::Index->new({
1607 engine => $engine,
1608 });
1609
1610 my %blist_cache;
1611 #XXX q.v. the comments for this function.
1612 foreach my $entry ( $sector->chopped_up ) {
1613 my ($spot, $md5) = @{$entry};
1614 my $idx = ord( substr( $md5, $i, 1 ) );
1615
1616 # XXX This is inefficient
1617 my $blist = $blist_cache{$idx}
1618 ||= DBM::Deep::Engine::Sector::BucketList->new({
1619 engine => $engine,
1620 });
1621
1622 $new_index->set_entry( $idx => $blist->offset );
1623
1624 my $new_spot = $blist->write_at_next_open( $md5 );
1625 $engine->reindex_entry( $spot => $new_spot );
1626 }
1627
1628 # Handle the new item separately.
1629 {
1630 my $idx = ord( substr( $args->{key_md5}, $i, 1 ) );
1631 my $blist = $blist_cache{$idx}
1632 ||= DBM::Deep::Engine::Sector::BucketList->new({
1633 engine => $engine,
1634 });
1635
1636 $new_index->set_entry( $idx => $blist->offset );
1637
1638 #XXX THIS IS HACKY!
1639 $blist->find_md5( $args->{key_md5} );
1640 $blist->write_md5({
1641 key => $args->{key},
1642 key_md5 => $args->{key_md5},
1643 value => DBM::Deep::Engine::Sector::Null->new({
1644 engine => $engine,
1645 data => undef,
1646 }),
1647 });
1648 }
1649
1650 if ( $last_sector ) {
1651 $last_sector->set_entry(
1652 ord( substr( $args->{key_md5}, $i - 1, 1 ) ),
1653 $new_index->offset,
1654 );
1655 } else {
1656 $engine->storage->print_at( $self->offset + $self->base_size,
1657 pack( $StP{$engine->byte_size}, $new_index->offset ),
1658 );
1659 }
1660
90fb1a24 1661 $sector->clear;
9a63e1f2 1662 $sector->free;
1663
1664 $sector = $blist_cache{ ord( substr( $args->{key_md5}, $i, 1 ) ) };
1665 $sector->find_md5( $args->{key_md5} );
1666 }
1667
1668 return $sector;
1669}
1670
1671sub get_class_offset {
1672 my $self = shift;
1673
1674 my $e = $self->engine;
ea2f6d67 1675 return unpack(
9a63e1f2 1676 $StP{$e->byte_size},
1677 $e->storage->read_at(
1678 $self->offset + $self->base_size + 1 * $e->byte_size, $e->byte_size,
75be6413 1679 ),
1680 );
75be6413 1681}
1682
9a63e1f2 1683sub get_classname {
d608b06e 1684 my $self = shift;
21838116 1685
9a63e1f2 1686 my $class_offset = $self->get_class_offset;
1687
1688 return unless $class_offset;
1689
1690 return $self->engine->_load_sector( $class_offset )->data;
1691}
1692
1693#XXX Add singleton handling here
1694sub data {
1695 my $self = shift;
1696
1697 my $new_obj = DBM::Deep->new({
1698 type => $self->type,
1699 base_offset => $self->offset,
1700 staleness => $self->staleness,
1701 storage => $self->engine->storage,
1702 engine => $self->engine,
1703 });
1704
1705 if ( $self->engine->storage->{autobless} ) {
1706 my $classname = $self->get_classname;
1707 if ( defined $classname ) {
1708 bless $new_obj, $classname;
1709 }
1710 }
1711
1712 return $new_obj;
1713}
1714
e137c258 1715sub increment_refcount {
1716 my $self = shift;
1717
1718 my $e = $self->engine;
1719 my $refcount = unpack(
1720 $StP{$e->byte_size},
1721 $e->storage->read_at(
1722 $self->offset + $self->base_size + 2 * $e->byte_size, $e->byte_size,
1723 ),
1724 );
1725
1726 $refcount++;
1727
1728 $e->storage->print_at(
1729 $self->offset + $self->base_size + 2 * $e->byte_size,
1730 pack( $StP{$e->byte_size}, $refcount ),
1731 );
1732
1733 return $refcount;
1734}
1735
1736sub decrement_refcount {
1737 my $self = shift;
1738
1739 my $e = $self->engine;
1740 my $refcount = unpack(
1741 $StP{$e->byte_size},
1742 $e->storage->read_at(
1743 $self->offset + $self->base_size + 2 * $e->byte_size, $e->byte_size,
1744 ),
1745 );
1746
1747 $refcount--;
1748
1749 $e->storage->print_at(
1750 $self->offset + $self->base_size + 2 * $e->byte_size,
1751 pack( $StP{$e->byte_size}, $refcount ),
1752 );
1753
1754 return $refcount;
1755}
1756
1757sub get_refcount {
1758 my $self = shift;
1759
1760 my $e = $self->engine;
1761 return unpack(
1762 $StP{$e->byte_size},
1763 $e->storage->read_at(
1764 $self->offset + $self->base_size + 2 * $e->byte_size, $e->byte_size,
1765 ),
1766 );
1767}
1768
9a63e1f2 1769package DBM::Deep::Engine::Sector::BucketList;
1770
1771our @ISA = qw( DBM::Deep::Engine::Sector );
1772
1773sub _init {
1774 my $self = shift;
1775
1776 my $engine = $self->engine;
1777
1778 unless ( $self->offset ) {
1779 my $leftover = $self->size - $self->base_size;
1780
1781 $self->{offset} = $engine->_request_blist_sector( $self->size );
1782 $engine->storage->print_at( $self->offset, $engine->SIG_BLIST ); # Sector type
1783 # Skip staleness counter
1784 $engine->storage->print_at( $self->offset + $self->base_size,
1785 chr(0) x $leftover, # Zero-fill the data
9a187d8c 1786 );
9a63e1f2 1787 }
d608b06e 1788
9a63e1f2 1789 if ( $self->{key_md5} ) {
1790 $self->find_md5;
d608b06e 1791 }
1792
9a63e1f2 1793 return $self;
d608b06e 1794}
1795
90fb1a24 1796sub clear {
1797 my $self = shift;
1798 $self->engine->storage->print_at( $self->offset + $self->base_size,
1799 chr(0) x ($self->size - $self->base_size), # Zero-fill the data
1800 );
1801}
1802
9a63e1f2 1803sub size {
994ccd8e 1804 my $self = shift;
9a63e1f2 1805 unless ( $self->{size} ) {
1806 my $e = $self->engine;
1807 # Base + numbuckets * bucketsize
1808 $self->{size} = $self->base_size + $e->max_buckets * $self->bucket_size;
1809 }
1810 return $self->{size};
1811}
994ccd8e 1812
9a63e1f2 1813sub free_meth { return '_add_free_blist_sector' }
7b1e1aa1 1814
9f83dc31 1815sub free {
1816 my $self = shift;
1817
1818 my $e = $self->engine;
1819 foreach my $bucket ( $self->chopped_up ) {
1820 my $rest = $bucket->[-1];
1821
1822 # Delete the keysector
1823 my $l = unpack( $StP{$e->byte_size}, substr( $rest, $e->hash_size, $e->byte_size ) );
1824 my $s = $e->_load_sector( $l ); $s->free if $s;
1825
1826 foreach my $txn ( 0 .. $e->num_txns - 1 ) {
1827 my $l = unpack( $StP{$e->byte_size},
1828 substr( $rest,
1829 $e->hash_size + $e->byte_size + $txn * ($e->byte_size + $STALE_SIZE),
1830 $e->byte_size,
1831 ),
1832 );
1833 my $s = $e->_load_sector( $l ); $s->free if $s;
1834 }
1835 }
1836
1837 $self->SUPER::free();
1838}
1839
9a63e1f2 1840sub bucket_size {
1841 my $self = shift;
1842 unless ( $self->{bucket_size} ) {
1843 my $e = $self->engine;
1844 # Key + head (location) + transactions (location + staleness-counter)
f72b2dfb 1845 my $location_size = $e->byte_size + $e->byte_size + ($e->num_txns - 1) * ($e->byte_size + $STALE_SIZE);
9a63e1f2 1846 $self->{bucket_size} = $e->hash_size + $location_size;
1847 }
1848 return $self->{bucket_size};
1849}
7b1e1aa1 1850
9a63e1f2 1851# XXX This is such a poor hack. I need to rethink this code.
1852sub chopped_up {
1853 my $self = shift;
1854
1855 my $e = $self->engine;
1856
1857 my @buckets;
1858 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
1859 my $spot = $self->offset + $self->base_size + $idx * $self->bucket_size;
1860 my $md5 = $e->storage->read_at( $spot, $e->hash_size );
1861
1862 #XXX If we're chopping, why would we ever have the blank_md5?
1863 last if $md5 eq $e->blank_md5;
1864
1865 my $rest = $e->storage->read_at( undef, $self->bucket_size - $e->hash_size );
1866 push @buckets, [ $spot, $md5 . $rest ];
1867 }
1868
1869 return @buckets;
994ccd8e 1870}
1871
9a63e1f2 1872sub write_at_next_open {
1873 my $self = shift;
1874 my ($entry) = @_;
1875
1876 #XXX This is such a hack!
1877 $self->{_next_open} = 0 unless exists $self->{_next_open};
1878
1879 my $spot = $self->offset + $self->base_size + $self->{_next_open}++ * $self->bucket_size;
1880 $self->engine->storage->print_at( $spot, $entry );
1881
1882 return $spot;
e96daec8 1883}
1884
9a63e1f2 1885sub has_md5 {
1886 my $self = shift;
1887 unless ( exists $self->{found} ) {
1888 $self->find_md5;
1889 }
1890 return $self->{found};
1891}
86867f3a 1892
9a63e1f2 1893sub find_md5 {
1894 my $self = shift;
1895
1896 $self->{found} = undef;
1897 $self->{idx} = -1;
1898
1899 if ( @_ ) {
1900 $self->{key_md5} = shift;
1901 }
1902
1903 # If we don't have an MD5, then what are we supposed to do?
1904 unless ( exists $self->{key_md5} ) {
1905 DBM::Deep->_throw_error( "Cannot find_md5 without a key_md5 set" );
1906 }
1907
1908 my $e = $self->engine;
1909 foreach my $idx ( 0 .. $e->max_buckets - 1 ) {
1910 my $potential = $e->storage->read_at(
1911 $self->offset + $self->base_size + $idx * $self->bucket_size, $e->hash_size,
1912 );
1913
1914 if ( $potential eq $e->blank_md5 ) {
1915 $self->{idx} = $idx;
86867f3a 1916 return;
9a63e1f2 1917 }
1918
1919 if ( $potential eq $self->{key_md5} ) {
1920 $self->{found} = 1;
1921 $self->{idx} = $idx;
86867f3a 1922 return;
9a63e1f2 1923 }
86867f3a 1924 }
1925
1926 return;
1927}
1928
9a63e1f2 1929sub write_md5 {
86867f3a 1930 my $self = shift;
9a63e1f2 1931 my ($args) = @_;
1932
1933 DBM::Deep->_throw_error( "write_md5: no key" ) unless exists $args->{key};
1934 DBM::Deep->_throw_error( "write_md5: no key_md5" ) unless exists $args->{key_md5};
1935 DBM::Deep->_throw_error( "write_md5: no value" ) unless exists $args->{value};
86867f3a 1936
9a63e1f2 1937 my $engine = $self->engine;
86867f3a 1938
9a63e1f2 1939 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
86867f3a 1940
9a63e1f2 1941 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1942 $engine->add_entry( $args->{trans_id}, $spot );
1943
1944 unless ($self->{found}) {
1945 my $key_sector = DBM::Deep::Engine::Sector::Scalar->new({
1946 engine => $engine,
1947 data => $args->{key},
1948 });
1949
1950 $engine->storage->print_at( $spot,
1951 $args->{key_md5},
1952 pack( $StP{$engine->byte_size}, $key_sector->offset ),
1953 );
86867f3a 1954 }
1955
9a63e1f2 1956 my $loc = $spot
1957 + $engine->hash_size
f72b2dfb 1958 + $engine->byte_size;
9a63e1f2 1959
f72b2dfb 1960 if ( $args->{trans_id} ) {
1961 $loc += $engine->byte_size + ($args->{trans_id} - 1) * ( $engine->byte_size + $STALE_SIZE );
1962
1963 $engine->storage->print_at( $loc,
1964 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
1965 pack( $StP{$STALE_SIZE}, $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
1966 );
1967 }
1968 else {
1969 $engine->storage->print_at( $loc,
1970 pack( $StP{$engine->byte_size}, $args->{value}->offset ),
1971 );
1972 }
9a63e1f2 1973}
1974
1975sub mark_deleted {
1976 my $self = shift;
1977 my ($args) = @_;
1978 $args ||= {};
1979
1980 my $engine = $self->engine;
1981
1982 $args->{trans_id} = $engine->trans_id unless exists $args->{trans_id};
1983
1984 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
1985 $engine->add_entry( $args->{trans_id}, $spot );
1986
1987 my $loc = $spot
1988 + $engine->hash_size
f72b2dfb 1989 + $engine->byte_size;
1990
1991 if ( $args->{trans_id} ) {
1992 $loc += $engine->byte_size + ($args->{trans_id} - 1) * ( $engine->byte_size + $STALE_SIZE );
1993
1994 $engine->storage->print_at( $loc,
1995 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
1996 pack( $StP{$STALE_SIZE}, $engine->get_txn_staleness_counter( $args->{trans_id} ) ),
1997 );
1998 }
1999 else {
2000 $engine->storage->print_at( $loc,
2001 pack( $StP{$engine->byte_size}, 1 ), # 1 is the marker for deleted
2002 );
2003 }
9a63e1f2 2004
9a63e1f2 2005}
2006
2007sub delete_md5 {
2008 my $self = shift;
2009 my ($args) = @_;
2010
2011 my $engine = $self->engine;
2012 return undef unless $self->{found};
2013
2014 # Save the location so that we can free the data
2015 my $location = $self->get_data_location_for({
2016 allow_head => 0,
2017 });
2018 my $key_sector = $self->get_key_for;
2019
2020 my $spot = $self->offset + $self->base_size + $self->{idx} * $self->bucket_size;
2021 $engine->storage->print_at( $spot,
2022 $engine->storage->read_at(
2023 $spot + $self->bucket_size,
2024 $self->bucket_size * ( $engine->max_buckets - $self->{idx} - 1 ),
2025 ),
2026 chr(0) x $self->bucket_size,
2027 );
2028
2029 $key_sector->free;
2030
2031 my $data_sector = $self->engine->_load_sector( $location );
2032 my $data = $data_sector->data;
2033 $data_sector->free;
2034
2035 return $data;
2036}
2037
2038sub get_data_location_for {
2039 my $self = shift;
2040 my ($args) = @_;
2041 $args ||= {};
2042
2043 $args->{allow_head} = 0 unless exists $args->{allow_head};
2044 $args->{trans_id} = $self->engine->trans_id unless exists $args->{trans_id};
2045 $args->{idx} = $self->{idx} unless exists $args->{idx};
2046
2047 my $e = $self->engine;
2048
2049 my $spot = $self->offset + $self->base_size
2050 + $args->{idx} * $self->bucket_size
2051 + $e->hash_size
f72b2dfb 2052 + $e->byte_size;
2053
2054 if ( $args->{trans_id} ) {
2055 $spot += $e->byte_size + ($args->{trans_id} - 1) * ( $e->byte_size + $STALE_SIZE );
2056 }
9a63e1f2 2057
2058 my $buffer = $e->storage->read_at(
2059 $spot,
f72b2dfb 2060 $e->byte_size + $STALE_SIZE,
9a63e1f2 2061 );
f72b2dfb 2062 my ($loc, $staleness) = unpack( $StP{$e->byte_size} . ' ' . $StP{$STALE_SIZE}, $buffer );
2063
2064 if ( $args->{trans_id} ) {
2065 # We have found an entry that is old, so get rid of it
2066 if ( $staleness != (my $s = $e->get_txn_staleness_counter( $args->{trans_id} ) ) ) {
2067 $e->storage->print_at(
2068 $spot,
2069 pack( $StP{$e->byte_size} . ' ' . $StP{$STALE_SIZE}, (0) x 2 ),
2070 );
2071 $loc = 0;
2072 }
86867f3a 2073 }
2074
9a63e1f2 2075 # If we're in a transaction and we never wrote to this location, try the
2076 # HEAD instead.
2077 if ( $args->{trans_id} && !$loc && $args->{allow_head} ) {
2078 return $self->get_data_location_for({
2079 trans_id => 0,
2080 allow_head => 1,
2081 idx => $args->{idx},
2082 });
2083 }
2084 return $loc <= 1 ? 0 : $loc;
2085}
2086
2087sub get_data_for {
2088 my $self = shift;
2089 my ($args) = @_;
2090 $args ||= {};
2091
2092 return unless $self->{found};
2093 my $location = $self->get_data_location_for({
2094 allow_head => $args->{allow_head},
2095 });
2096 return $self->engine->_load_sector( $location );
2097}
2098
2099sub get_key_for {
2100 my $self = shift;
2101 my ($idx) = @_;
2102 $idx = $self->{idx} unless defined $idx;
2103
2104 if ( $idx >= $self->engine->max_buckets ) {
2105 DBM::Deep->_throw_error( "get_key_for(): Attempting to retrieve $idx" );
86867f3a 2106 }
2107
9a63e1f2 2108 my $location = $self->engine->storage->read_at(
2109 $self->offset + $self->base_size + $idx * $self->bucket_size + $self->engine->hash_size,
2110 $self->engine->byte_size,
2111 );
2112 $location = unpack( $StP{$self->engine->byte_size}, $location );
2113 DBM::Deep->_throw_error( "get_key_for: No location?" ) unless $location;
2114
2115 return $self->engine->_load_sector( $location );
2116}
86867f3a 2117
9a63e1f2 2118package DBM::Deep::Engine::Sector::Index;
2119
2120our @ISA = qw( DBM::Deep::Engine::Sector );
2121
2122sub _init {
2123 my $self = shift;
2124
2125 my $engine = $self->engine;
2126
2127 unless ( $self->offset ) {
2128 my $leftover = $self->size - $self->base_size;
2129
2130 $self->{offset} = $engine->_request_index_sector( $self->size );
2131 $engine->storage->print_at( $self->offset, $engine->SIG_INDEX ); # Sector type
2132 # Skip staleness counter
2133 $engine->storage->print_at( $self->offset + $self->base_size,
2134 chr(0) x $leftover, # Zero-fill the rest
2135 );
2136 }
2137
2138 return $self;
2139}
2140
f72b2dfb 2141#XXX Change here
9a63e1f2 2142sub size {
2143 my $self = shift;
2144 unless ( $self->{size} ) {
2145 my $e = $self->engine;
2146 $self->{size} = $self->base_size + $e->byte_size * $e->hash_chars;
2147 }
2148 return $self->{size};
2149}
2150
2151sub free_meth { return '_add_free_index_sector' }
2152
2153sub free {
2154 my $self = shift;
2155 my $e = $self->engine;
2156
2157 for my $i ( 0 .. $e->hash_chars - 1 ) {
2158 my $l = $self->get_entry( $i ) or next;
2159 $e->_load_sector( $l )->free;
86867f3a 2160 }
2161
9a63e1f2 2162 $self->SUPER::free();
2163}
2164
2165sub _loc_for {
2166 my $self = shift;
2167 my ($idx) = @_;
2168 return $self->offset + $self->base_size + $idx * $self->engine->byte_size;
2169}
2170
2171sub get_entry {
2172 my $self = shift;
2173 my ($idx) = @_;
2174
2175 my $e = $self->engine;
2176
2177 DBM::Deep->_throw_error( "get_entry: Out of range ($idx)" )
2178 if $idx < 0 || $idx >= $e->hash_chars;
2179
2180 return unpack(
2181 $StP{$e->byte_size},
2182 $e->storage->read_at( $self->_loc_for( $idx ), $e->byte_size ),
2183 );
2184}
2185
2186sub set_entry {
2187 my $self = shift;
2188 my ($idx, $loc) = @_;
2189
2190 my $e = $self->engine;
2191
2192 DBM::Deep->_throw_error( "set_entry: Out of range ($idx)" )
2193 if $idx < 0 || $idx >= $e->hash_chars;
2194
2195 $self->engine->storage->print_at(
2196 $self->_loc_for( $idx ),
2197 pack( $StP{$e->byte_size}, $loc ),
2198 );
86867f3a 2199}
2200
a20d9a3f 22011;
2202__END__