--- a/SelectionInTree.st	Mon Mar 09 17:07:25 1998 +0100
+++ b/SelectionInTree.st	Mon Mar 09 17:08:44 1998 +0100
@@ -14,7 +14,7 @@
 
 Model subclass:#SelectionInTree
 	instanceVariableNames:'root list selection showRoot contentsAction labelAction
-		childrenAction iconAction'
+		childrenAction iconAction indicatorList indicatorTask accessLock'
 	classVariableNames:''
 	poolDictionaries:''
 	category:'Interface-Support-Models'
@@ -55,6 +55,12 @@
 "
 ! !
 
+!SelectionInTree class methodsFor:'instance creation'!
+
+new
+    ^ super new initialize
+! !
+
 !SelectionInTree methodsFor:'accessing'!
 
 list
@@ -75,6 +81,7 @@
     root notNil ifTrue: [
         root tree: nil
     ].
+    self stopRunningTasks.
 
     (root := aRoot) notNil ifTrue:[
         root parent:nil.
@@ -255,6 +262,8 @@
     |invalidate|
 
     self each:something do:[:aNode|
+        self stopIndicatorValidationFor:aNode.
+
         aNode parent notNil ifTrue:[
             aNode parent remove:aNode.
             invalidate := true
@@ -262,6 +271,7 @@
     ].
     invalidate == true ifTrue:[self recomputeList].
   ^ something
+
 !
 
 removeIndex:something
@@ -278,6 +288,7 @@
 
     (SortedCollection withAll:something) reverseDo:[:anIndex|
         node := list at:anIndex.
+        self stopIndicatorValidationFor:node.
 
         node parent notNil ifTrue:[
             node parent remove:node.
@@ -285,6 +296,7 @@
         ]
     ].
     invalidate == true ifTrue:[self recomputeList].
+
 !
 
 removeSelection
@@ -330,8 +342,12 @@
 !SelectionInTree methodsFor:'initialization'!
 
 initialize
+
+    showRoot := true.
+    indicatorList := OrderedCollection new.
+    accessLock    := Semaphore forMutualExclusion.
     super initialize.
-    showRoot := true.
+
 ! !
 
 !SelectionInTree methodsFor:'private'!
@@ -405,8 +421,78 @@
 
 ! !
 
+!SelectionInTree methodsFor:'update indication task'!
+
+startIndicatorValidationFor:aNode
+    "add a node to list of updating indications
+    "
+    |index|
+
+    accessLock critical:[
+        index := indicatorList identityIndexOf:aNode.
+
+        index ~~ 0 ifTrue:[
+            indicatorList removeIndex:index.    "/ reorganize list to be faster
+        ].
+        indicatorList addFirst:aNode.
+
+        indicatorTask isNil ifTrue:[
+            indicatorTask := [
+                [ self taskCycle ] whileTrue:[ Processor yield ]
+            ] forkAt:(Processor activePriority - 1)
+        ]
+    ].
+!
+
+stopIndicatorValidationFor:aNodeOrList
+    "remove a node or list of nodes from list of updating indications
+    "
+    accessLock critical:[
+        aNodeOrList isCollection ifTrue:[
+            aNodeOrList do:[:aNode|
+                indicatorList removeIdentical:aNode ifAbsent:nil
+            ]
+        ] ifFalse:[
+            indicatorList removeIdentical:aNodeOrList ifAbsent:nil
+        ]
+    ]
+
+
+!
+
+stopRunningTasks
+    "stop task
+    "
+    accessLock critical:[ indicatorList removeAll ]
+
+!
+
+taskCycle
+    "run one cycle
+    "
+    |node|
+
+    accessLock critical:[
+        indicatorList isEmpty ifTrue:[          "/ queue is empty; terminate task
+            indicatorTask := nil.
+            ^ false
+        ].
+        node := indicatorList removeFirst.      "/ run task on first node
+
+        node hasValidIndicator ifTrue:[         "/ up to date
+            ^ true
+        ].
+        node setShowIndicator:false             "/ disable registry
+    ].
+
+    (DirectoryContents directoryNamed:(node fileName) detect:(node matchAction)) ifTrue:[
+        node showIndicator:true
+    ].
+    ^ true
+! !
+
 !SelectionInTree class methodsFor:'documentation'!
 
 version
-    ^ '$Header: /cvs/stx/stx/libwidg2/SelectionInTree.st,v 1.9 1998-02-14 16:15:32 tz Exp $'
+    ^ '$Header: /cvs/stx/stx/libwidg2/SelectionInTree.st,v 1.10 1998-03-09 16:08:25 ca Exp $'
 ! !