Fix unlikely but possible race in `WeakValueDictionary`
It may happen that value in `valueArray` could have been already
collected by the GC but #clearDeadSlots have not yet been called.
When this happened, `#at:ifAbsentPut:` returned tombstone rather
than updating the dictionary with value from block.
This commit fixes this by checking whether `valueArray` contain
the tombstone and if so, clearing up the dead slots and restarting
the operation. HTH.
"
COPYRIGHT (c) 1995 by Claus Gittinger
All Rights Reserved
This software is furnished under a license and may be used
only in accordance with the terms of that license and with the
inclusion of the above copyright notice. This software may not
be provided or otherwise made available to, or used by, any
other person. No title to or ownership of the software is
hereby transferred.
"
"{ Package: 'stx:libbasic' }"
"{ NameSpace: Smalltalk }"
Registry subclass:#HandleRegistry
instanceVariableNames:''
classVariableNames:''
poolDictionaries:''
category:'System-Support'
!
!HandleRegistry class methodsFor:'documentation'!
copyright
"
COPYRIGHT (c) 1995 by Claus Gittinger
All Rights Reserved
This software is furnished under a license and may be used
only in accordance with the terms of that license and with the
inclusion of the above copyright notice. This software may not
be provided or otherwise made available to, or used by, any
other person. No title to or ownership of the software is
hereby transferred.
"
!
documentation
"
HandleRegistries are like Registries, in that they watch for the death of
a registered object. However, they send a self-change notification, passing the registered
handle as argument, instead of creating a shallow copy and letting it do the finalization.
Use Registry for objects which know themself how to clean up;
use HandleRegistry, if someone else does the cleanup.
[author:]
Claus Gittinger
"
! !
!HandleRegistry methodsFor:'dispose handling'!
informDispose:someHandle
"an element was disposed; let my dependents know about this"
self changed:#finalize with:someHandle
! !
!HandleRegistry methodsFor:'redefined to block'!
register:anObject
"not useful for HandleRegistry - use #register:as:"
self shouldNotImplement
!
registerChange:anObject
"not useful for HandleRegistry"
self shouldNotImplement
! !
!HandleRegistry class methodsFor:'documentation'!
version
^ '$Header$'
!
version_SVN
^ '$Id: HandleRegistry.st 10761 2012-01-19 11:46:00Z vranyj1 $'
! !