[squeak-dev] The Inbox: Kernel-jar.1377.mcz

commits at source.squeak.org commits at source.squeak.org
Wed Mar 3 22:06:50 UTC 2021


A new version of Kernel was added to project The Inbox:
http://source.squeak.org/inbox/Kernel-jar.1377.mcz

==================== Summary ====================

Name: Kernel-jar.1377
Author: jar
Time: 3 March 2021, 11:06:44.192499 pm
UUID: b99e562a-887b-7e4e-9c11-6818ca1acaeb
Ancestors: Kernel-nice.1376

Fix inconsistent bahavior in #isTerminated and #isSuspended

=============== Diff against Kernel-nice.1376 ===============

Item was changed:
  ----- Method: Process>>isSuspended (in category 'testing') -----
  isSuspended
+ 	"A process is suspended if it has non-nil suspendedContext (e.g. new or 
+ 	previously suspended with the suspend primitive) and is not terminated or
+ 	waiting in a scheduler or a semaphore queue (i.e. is not runnable or blocked)."
+ 	
+ 	^myList isNil
+ 		and: [suspendedContext notNil]
+ 		and: [self isTerminated not]!
- 	"A process is suspended if it has been suspended with the suspend primitive.
- 	 It is distinguishable from the active process and a terminated process by
- 	 having a non-nil suspendedContext that is either not the bottom context
- 	 or has not reached its endPC."
- 	^nil == myList
- 	  and: [nil ~~ suspendedContext
- 	  and: [suspendedContext isBottomContext
- 			ifTrue: [suspendedContext closure
- 						ifNil: [suspendedContext methodClass ~~ Process
- 							or: [suspendedContext selector ~~ #terminate]]
- 						ifNotNil: [suspendedContext pc < suspendedContext closure endPC]]
- 			ifFalse: [true]]]!

Item was changed:
  ----- Method: Process>>isTerminated (in category 'testing') -----
  isTerminated
+ 	"Answer if the receiver is terminated, or at least terminating, i.e. if one 
+ 	of the following conditions is satisfied:
+ 	(1) the receiver is a defunct process (suspendedContext = nil or pc = nil)
+ 	(2) we catch the active process termination by adding a first temporary 
+ 	in Process>>terminate called terminationStatus and having Process>>
+ 	terminate assign #terminated to it when termination is essentially complete
+ 	(3) the suspendedContext is the bottomContext and the pc is at the endPC"
+ 
+ 	self isActiveProcess ifTrue: [^false].
- 	"Answer if the receiver is terminated, or at least terminating."
- 	self isActiveProcess ifTrue: [^ false].
  	^suspendedContext isNil
+ 	or: [suspendedContext isDead]
+ 	or: [suspendedContext methodClass == Process
+ 		and: [suspendedContext selector == #terminate]
+ 		and: [(suspendedContext tempAt: 1) == #terminated]]
+ 	or: [suspendedContext isBottomContext and: [suspendedContext atEnd]]!
- 	  or: ["If the suspendedContext is the bottomContext it is the block in Process>>newProcess.
- 		   If so, and the pc is at the endPC, the block has already sent and returned
- 		   from value and there is nothing more to do."
- 		suspendedContext isBottomContext
- 		and: [suspendedContext closure
- 						ifNil: [suspendedContext methodClass == Process
- 							and: [suspendedContext selector == #terminate]]
- 						ifNotNil: [suspendedContext pc >= suspendedContext closure endPC]]]!

Item was changed:
  ----- Method: Process>>terminate (in category 'changing process state') -----
  terminate 
  	"Stop the process that the receiver represents forever.
  	 Unwind to execute pending ensure:/ifCurtailed: blocks before terminating.
  	 If the process is in the middle of a critical: critical section, release it properly."
  
+ 	| terminationStatus ctxt unwindBlock oldList |
- 	| ctxt unwindBlock oldList |
  	self isActiveProcess ifTrue:
  		[ctxt := thisContext.
  		 [ctxt := ctxt findNextUnwindContextUpTo: nil.
  		  ctxt ~~ nil] whileTrue:
  			[(ctxt tempAt: 2) ifNil:
  				["N.B. Unlike Context>>unwindTo: we do not set complete (tempAt: 2) to true."
  				 unwindBlock := ctxt tempAt: 1.
  				 thisContext terminateTo: ctxt.
  				 unwindBlock value]].
  		thisContext terminateTo: nil.
+ 		terminationStatus := #terminated.
  		self suspend.
  		"If the process is resumed this will provoke a cannotReturn: error.
  		 Would self debug: thisContext title: 'Resuming a terminated process' be better?"
  		^self].
  
  	"Always suspend the process first so it doesn't accidentally get woken up.
  	 N.B. If oldList is a LinkedList then the process is runnable. If it is a Semaphore/Mutex et al
  	 then the process is blocked, and if it is nil then the process is already suspended."
  	oldList := self suspend.
  	suspendedContext ifNotNil:
  		["Release any method marked with the <criticalSection> pragma.
  		  The argument is whether the process is runnable."
  		 self releaseCriticalSection: (oldList isNil or: [oldList class == LinkedList]).
  
  		"If terminating a process halfways through an unwind, try to complete that unwind block first."
  		(suspendedContext findNextUnwindContextUpTo: nil) ifNotNil:
  			[:outer|
  			 (suspendedContext findContextSuchThat:[:c| c closure == (outer tempAt: 1)]) ifNotNil:
  				[:inner| "This is an unwind block currently under evaluation"
  				 suspendedContext runUntilErrorOrReturnFrom: inner]].
  
  		ctxt := self popTo: suspendedContext bottomContext.
  		ctxt == suspendedContext bottomContext ifFalse:
  			[self debug: ctxt title: 'Unwind error during termination'].
  		"Set the context to its endPC for the benefit of isTerminated."
  		ctxt pc: ctxt endPC]!



More information about the Squeak-dev mailing list