timer: Another approach to fix the issues on Pharo

Pharo's DateAndTime/Delay and VM interaction is bogus. If we execute
DateAndTime/Delay too early things will get stuck and take 100% of
the CPU.

Timer.st

@@ -67,7 +67,7 @@ Object subclass: Timer [
 ]
 
 Object subclass: TimerScheduler [
-    | queue sem loop quit lastDelay |
+    | queue sem loop quit processExited |
     <category: 'OsmoCore-Timer'>
     <comment: 'I can help to fire things at the right time. Right now I
 only work on seconds granularity because Time has no direct access to
@@ -94,26 +94,21 @@ bit difficult to do this race free.'>
         quit := true.
     ]
 
-    platformInit [
-        <category: 'creation'>
-        "Nothing for GST..."
-    ]
-
     initialize [
         <category: 'private'>
         queue := SortedCollection sortBlock: [:a :b | a timeout < b timeout].
         sem := Semaphore forMutualExclusion.
         quit := false.
-        self
-            startLoop;
-            platformInit.
+        self startLoop.
     ]
 
     startLoop [
         <category: 'creation'>
 
-        loop := [Processor activeProcess name: 'Osmo Timers'.
-                 self runTimers] fork.
+        processExited := Semaphore new.
+        loop := [[Processor activeProcess name: 'Osmo Timers'.
+                self runTimers
+                ] ensure: [processExited signal. loop := nil]] fork
     ]
 
     scheduleInSeconds: aDelay block: aBlock [
@@ -135,12 +130,7 @@ bit difficult to do this race free.'>
         <category: 'delay_loop'>
 
         [quit] whileFalse: [ | now |
-
-            "Remember the last delay so we can interrupt it on image resume on Pharo"
-            lastDelay := Delay forSeconds: 1.
-            lastDelay wait.
-            lastDelay := nil.
-
+            (Delay forSeconds: 1) wait.
             now := DateTime now.
             OsmoDispatcher dispatchBlock: [self fireTimers: now].
         ]

changes_for_pharo.st

@@ -1,25 +1,34 @@
 TimerScheduler extend [
     TimerScheduler class >> initialize [
         <category: 'loading'>
-        ^ self instance
+        "Pharo requires us to do some post-processing"
+        Smalltalk addToStartUpList: self.
+        Smalltalk addToShutDownList: self.
+        ^self instance.
     ]
 
     TimerScheduler class >> startUp [
-        Smalltalk at: #OsmoTimeScheduler ifPresent: [
-            OsmoTimeScheduler reinitialize.
-        ].
+        Smalltalk at: #OsmoTimeScheduler ifPresent: [:timer | timer doStartUp].
     ]
 
-    platformInit [
-        <category: 'creation'>
-        "Pharo requires us to do some post-processing"
-        Smalltalk addToStartUpList: self class.
+    TimerScheduler class >> shutDown: quitting [
+        Smalltalk at: #OsmoTimeScheduler ifPresent: [:timer | timer doShutDown].
     ]
 
-    reinitialize [
-        <category: 'creation'>
-        "(Delay forSeconds: 1) wait can get stuck in Pharo for-ever.. Change the approach"
-        lastDelay ifNotNil: [lastDelay signalWaitingProcess]
+    doShutDown [
+        <category: 'PharoHacks'>
+        loop ifNil: [^self].
+        quit := true.
+        processExited wait.
+        Transcript nextPutAll: 'Stopped the TimerScheduler process'; cr.
+    ]
+
+    doStartUp [
+        <category: 'PharoHacks'>
+        loop ifNotNil: [^self error: 'The loop should have vanished'].
+        Transcript nextPutAll: 'Starting the TimerScheduler loop again'; cr.
+        quit := false.
+        self startLoop.
     ]
 ]