/usr/share/gnu-smalltalk/kernel/WeakObjects.st is in gnu-smalltalk-common 3.2.5-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 | "=====================================================================
|
| Weak collections
|
|
======================================================================"
"======================================================================
|
| Copyright 1999,2000,2001,2002,2007,2008,2009 Free Software Foundation, Inc.
| Written by Paolo Bonzini.
|
| This file is part of the GNU Smalltalk class library.
|
| The GNU Smalltalk class library is free software; you can redistribute it
| and/or modify it under the terms of the GNU Lesser General Public License
| as published by the Free Software Foundation; either version 2.1, or (at
| your option) any later version.
|
| The GNU Smalltalk class library is distributed in the hope that it will be
| useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
| General Public License for more details.
|
| You should have received a copy of the GNU Lesser General Public License
| along with the GNU Smalltalk class library; see the file COPYING.LIB.
| If not, write to the Free Software Foundation, 59 Temple Place - Suite
| 330, Boston, MA 02110-1301, USA.
|
======================================================================"
Array subclass: WeakArray [
| values nilValues |
<category: 'Collections-Weak'>
<comment: '
I am similar to a plain array, but my items are stored in a weak object,
so I track which of them are garbage collected.'>
WeakArray class >> new [
"Create a new WeakArray of size 0."
<category: 'instance creation'>
^self new: 0
]
WeakArray class >> new: size [
"Create a new WeakArray of the given size."
<category: 'instance creation'>
^self basicNew initialize: size
]
postLoad [
"Called after loading an object; must restore it to the state before
`preStore' was called. Make it weak again"
<category: 'loading'>
values makeWeak
]
initialize: size [
"Private - Initialize the values array; plus, make it weak and create
the ByteArray used to track garbage collected values"
<category: 'private'>
values := Array new: size.
values makeWeak.
nilValues := ByteArray new: size withAll: 1
]
values: anArray whichAreNil: nilArray [
"Private - Initialize the values array to anArray and make it weak;
plus, set to a copy of nilArray the ByteArray used to track garbage
collected values"
<category: 'private'>
values := anArray.
values makeWeak.
nilValues := ByteArray new: anArray size.
nilValues
replaceFrom: 1
to: anArray size
with: nilArray
startingAt: 1
]
at: index [
"Answer the index-th item of the receiver, or nil if it has been
garbage collected."
<category: 'accessing'>
^values at: index
]
atAll: indices put: object [
"Put object at every index contained in the indices collection"
<category: 'accessing'>
nilValues atAll: indices put: (object isNil ifTrue: [1] ifFalse: [0]).
^values atAll: indices put: object
]
atAllPut: object [
"Put object at every index in the receiver"
<category: 'accessing'>
nilValues atAllPut: (object isNil ifTrue: [1] ifFalse: [0]).
^values atAllPut: object
]
at: index put: object [
"Store the value associated to the given index; plus,
store in nilValues whether the object is nil. nil objects whose
associated item of nilValues is 1 were touched by the garbage
collector."
<category: 'accessing'>
nilValues at: index put: (object isNil ifTrue: [1] ifFalse: [0]).
^values at: index put: object
]
clearGCFlag: index [
"Clear the `object has been garbage collected' flag for the item
at the given index"
<category: 'accessing'>
| object |
object := values at: index.
nilValues at: index put: (object isNil ifTrue: [1] ifFalse: [0])
]
do: aBlock [
"Evaluate aBlock for all the elements in the array, including the
garbage collected ones (pass nil for those)."
<category: 'accessing'>
values do: aBlock
]
aliveObjectsDo: aBlock [
"Evaluate aBlock for all the elements in the array, excluding the
garbage collected ones. Note: a finalized object stays alive until
the next collection (the collector has no means to see whether it was
resuscitated by the finalizer), so an object being alive does not mean
that it is usable."
<category: 'accessing'>
| value |
1 to: self size
do:
[:i |
(value := values at: i) isNil
ifFalse: [aBlock value: value]
ifTrue: [(nilValues at: i) = 0 ifFalse: [aBlock value: value]]]
]
isAlive: index [
"Answer whether the item at the given index is still alive or has been
garbage collected. Note: a finalized object stays alive until the next
collection (the collector has no means to see whether it was resuscitated
by the finalizer), so an object being alive does not mean that it is
usable."
<category: 'accessing'>
^(values at: index) notNil or: [(nilValues at: index) = 1]
]
size [
"Answer the number of items in the receiver"
<category: 'accessing'>
^values size
]
asArray [
"Answer a non-weak version of the receiver"
<category: 'conversion'>
^values copy
]
deepCopy [
"Returns a deep copy of the receiver (the instance variables are
copies of the receiver's instance variables)"
<category: 'conversion'>
^self class basicNew values: values deepCopy whichAreNil: nilValues
]
shallowCopy [
"Returns a shallow copy of the receiver (the instance variables are
not copied)"
<category: 'conversion'>
^self class basicNew values: values shallowCopy whichAreNil: nilValues
]
species [
"Answer Array; this method is used in the #copyEmpty: message, which in
turn is used by all collection-returning methods (collect:, select:,
reject:, etc.)."
<category: 'conversion'>
^Array
]
]
Set subclass: WeakSet [
<shape: #pointer>
<category: 'Collections-Weak'>
<comment: '
I am similar to a plain set, but my items are stored in a weak array;
I track which of them are garbage collected and, as soon as I encounter
one of them, I swiftly remove all.'>
add: newObject [
"Add newObject to the set, if and only if the set doesn't already contain
an occurrence of it. Don't fail if a duplicate is found. Answer newObject"
<category: 'accessing'>
| index |
index := self findIndex: newObject.
(self primAt: index) isNil ifTrue: [
self incrementTally ifTrue: [index := self findIndex: newObject].
self primAt: index put: (self newAssociation: newObject)].
^newObject
]
do: aBlock [
"Enumerate all the non-nil members of the set"
<category: 'accessing'>
1 to: self primSize
do: [:i | (self primAt: i) notNil ifTrue: [aBlock value: (self primAt: i) key]]
]
postLoad [
"Called after loading an object; must restore it to the state before
`preStore' was called. Make it weak again"
<category: 'loading'>
1 to: self primSize
do: [:i | (self primAt: i) notNil ifTrue: [(self primAt: i) makeEphemeron]]
]
shallowCopy [
"Returns a shallow copy of the receiver (the instance variables are
not copied)"
<category: 'copying'>
| copy |
copy := self copyEmpty: self capacity.
self do: [:each | copy addWhileGrowing: (copy newAssociation: each)].
^copy
]
deepCopy [
"Returns a deep copy of the receiver (the instance variables are
copies of the receiver's instance variables)"
<category: 'copying'>
| copy |
copy := self copyEmpty: self capacity.
self do: [:each | copy addWhileGrowing: (copy newAssociation: each copy)].
^copy
]
newAssociation: key [
<category: 'private'>
^(HomedAssociation
key: key
value: nil
environment: self)
makeEphemeron;
yourself
]
mourn: anObject [
"Private - anObject has been found to have a weak key, remove it."
"What has to be passed to #remove: is the key, not the whole object."
<category: 'private'>
super mourn: anObject key
]
findElementIndex: anObject [
"Tries to see if anObject exists as an indexed variable. As soon as nil
is found, the index of that slot is answered"
<category: 'private methods'>
| index size element |
self beConsistent.
"Sorry for the lack of readability, but I want speed... :-)"
index := (anObject key hash scramble bitAnd: (size := self primSize) - 1) + 1.
[(element := self primAt: index) isNil
ifTrue: [^index].
index == size ifTrue: [index := 1] ifFalse: [index := index + 1]]
repeat
]
findIndex: anObject [
"Tries to see if anObject exists as an indexed variable. As soon as nil
or anObject is found, the index of that slot is answered"
<category: 'private'>
| index size element |
self beConsistent.
"Sorry for the lack of readability, but I want speed... :-)"
index := (anObject identityHash scramble
bitAnd: (size := self primSize) - 1) + 1.
[((element := self primAt: index) isNil or: [element key = anObject])
ifTrue: [^index].
index == size ifTrue: [index := 1] ifFalse: [index := index + 1]]
repeat
]
]
Dictionary subclass: WeakKeyDictionary [
| keys |
<shape: #pointer>
<category: 'Collections-Weak'>
<comment: '
I am similar to a plain Dictionary, but my keys are stored
in a weak array; I track which of them are garbage collected and, as
soon as I encounter one of them, I swiftly remove all the associations
for the garbage collected keys'>
WeakKeyDictionary class >> postLoad [
"Called after loading an object; must restore it to the state before
`preStore' was called. Make it weak again"
<category: 'hacks'>
1 to: self primSize
do: [:i | (self primAt: i) notNil ifTrue: [(self primAt: i) makeEphemeron]]
]
add: anAssociation [
"Store value as associated to the given key."
<category: 'accessing'>
| assoc |
assoc := anAssociation.
((assoc isKindOf: HomedAssociation) and: [assoc environment == self])
ifFalse:
[assoc := HomedAssociation
key: assoc key
value: assoc value
environment: self].
assoc makeEphemeron.
^super add: assoc
]
at: key put: value [
"Store value as associated to the given key."
<category: 'accessing'>
| assoc |
assoc := HomedAssociation
key: key
value: value
environment: self.
assoc makeEphemeron.
self add: assoc.
^value
]
]
LookupTable subclass: WeakValueLookupTable [
| values |
<shape: #pointer>
<category: 'Collections-Weak'>
<comment: '
I am similar to a plain LookupTable, but my values are stored
in a weak array; I track which of the values are garbage collected and,
as soon as one of them is accessed, I swiftly remove the associations
for the garbage collected values'>
WeakValueLookupTable class >> primNew: realSize [
"Answer a new, uninitialized instance of the receiver with the given size"
<category: 'hacks'>
^self basicNew: realSize
]
at: key ifAbsent: aBlock [
"Answer the value associated to the given key, or the result of evaluating
aBlock if the key is not found"
<category: 'hacks'>
| result |
result := super at: key ifAbsent: [^aBlock value].
result isNil ifFalse: [^result].
self beConsistent.
^super at: key ifAbsent: aBlock
]
at: key ifPresent: aBlock [
"If aKey is absent, answer nil. Else, evaluate aBlock passing the
associated value and answer the result of the invocation"
<category: 'hacks'>
^aBlock value: (self at: key ifAbsent: [^nil])
]
includesKey: key [
"Answer whether the receiver contains the given key."
<category: 'hacks'>
self at: key ifAbsent: [^false].
^true
]
beConsistent [
"Private - Clean the dictionary of key->(finalized value) pairs"
<category: 'private'>
| keys key |
keys := WriteStream on: (Array new: self size // 3 + 1).
1 to: self primSize
do:
[:index |
"Find values that are nil and should not be"
(values isAlive: index)
ifFalse:
[keys nextPut: (self primAt: index).
values clearGCFlag: index]].
self removeAllKeys: keys contents ifAbsent: [:key | ]
]
initialize: anInteger [
"Private - Initialize the values array; plus, make it weak and create
the ByteArray used to track garbage collected values"
<category: 'private'>
super initialize: anInteger.
values := WeakArray new: self primSize
]
primSize [
<category: 'private'>
^self basicSize
]
primAt: index [
<category: 'private'>
^self basicAt: index
]
primAt: index put: object [
<category: 'private'>
^self basicAt: index put: object
]
valueAt: index [
<category: 'private'>
^values at: index
]
valueAt: index put: object [
<category: 'private'>
^values at: index put: object
]
rehash [
"Rehash the receiver"
<category: 'rehashing'>
| key val |
key := Array new: self primSize.
val := Array new: values size.
self resetTally.
1 to: self primSize
do:
[:i |
"Find values that are nil and should not be"
(key := self primAt: i) notNil
ifTrue:
[(values isAlive: i)
ifTrue:
[key at: i put: (self primAt: i).
val at: i put: (self valueAt: i)]].
self primAt: i put: nil.
self valueAt: i put: nil].
1 to: self primSize
do:
[:i |
(key at: i) isNil
ifFalse: [self whileGrowingAt: (key at: i) put: (val at: i)]]
]
]
WeakSet subclass: WeakIdentitySet [
<shape: #pointer>
<category: 'Collections-Weak'>
<comment: '
I am similar to a plain identity set, but my keys are stored in a weak
array; I track which of them are garbage collected and, as soon as I
encounter one of them, I swiftly remove all the garbage collected keys'>
identityIncludes: anObject [
"Answer whether I include anObject exactly. As I am an
identity-set, this is the same as #includes:."
<category: 'accessing'>
^self includes: anObject
]
findIndex: anObject [
"Tries to see if anObject exists as an indexed variable. As soon as nil
or anObject is found, the index of that slot is answered"
<category: 'private methods'>
| index size element |
self beConsistent.
"Sorry for the lack of readability, but I want speed... :-)"
index := (anObject identityHash scramble
bitAnd: (size := self primSize) - 1) + 1.
[((element := self primAt: index) isNil or: [element key == anObject])
ifTrue: [^index].
index == size ifTrue: [index := 1] ifFalse: [index := index + 1]]
repeat
]
]
WeakKeyDictionary subclass: WeakKeyIdentityDictionary [
<shape: #pointer>
<category: 'Collections-Weak'>
<comment: '
I am similar to a plain identity dictionary, but my keys are stored
in a weak array; I track which of them are garbage collected and, as
soon as I encounter one of them, I swiftly remove all the associations
for the garbage collected keys'>
keysClass [
"Answer the class answered by #keys"
<category: 'private methods'>
^IdentitySet
]
hashFor: anObject [
"Return an hash value for the item, anObject"
<category: 'private methods'>
^anObject identityHash
]
findIndex: anObject [
"Tries to see if anObject exists as an indexed variable. As soon as nil
or anObject is found, the index of that slot is answered"
<category: 'private methods'>
| index size element |
self beConsistent.
"Sorry for the lack of readability, but I want speed... :-)"
index := (anObject identityHash scramble
bitAnd: (size := self primSize) - 1) + 1.
[((element := self primAt: index) isNil or: [element key == anObject])
ifTrue: [^index].
index == size ifTrue: [index := 1] ifFalse: [index := index + 1]]
repeat
]
]
WeakValueLookupTable subclass: WeakValueIdentityDictionary [
<shape: #pointer>
<category: 'Collections-Weak'>
<comment: '
I am similar to a plain identity dictionary, but my values are stored
in a weak array; I track which of the values are garbage collected and,
as soon as one of them is accessed, I swiftly remove the associations
for the garbage collected values'>
keysClass [
"Answer the class answered by #keys"
<category: 'private methods'>
^IdentitySet
]
hashFor: anObject [
"Return an hash value for the item, anObject"
<category: 'private methods'>
^anObject identityHash
]
findIndex: anObject [
"Tries to see if anObject exists as an indexed variable. As soon as nil
or anObject is found, the index of that slot is answered"
<category: 'private methods'>
| index size element |
self beConsistent.
"Sorry for the lack of readability, but I want speed... :-)"
index := (anObject identityHash scramble
bitAnd: (size := self primSize) - 1) + 1.
[((element := self primAt: index) isNil or: [element == anObject])
ifTrue: [^index].
index == size ifTrue: [index := 1] ifFalse: [index := index + 1]]
repeat
]
]
|