"{ Package: 'stx:libview2' }"

EventListener subclass:#ScreenLock

	instanceVariableNames:'workstation lastInactiveTime lockAfterSeconds lockChannel

		lockChannelOut processor lockedViews hiddenViews'

	classVariableNames:''

	poolDictionaries:''

	category:'Interface-Support'

!

!ScreenLock class methodsFor:'documentation'!

documentation

"

    documentation to be added.

    [author:]

	Stefan Vogel (stefan@nilpferd)

    [see also:]

    [instance variables:]

    [class variables:]

"

!

examples

"

                                                                [exBegin]

    |screenLock|

    screenLock := ScreenLock forDevice:Screen current.

    screenLock lock.

    Delay waitForSeconds:3.

    screenLock unlock.

    screenLock unlisten.

                                                                [exEnd]

                                                                [exBegin]

    |screenLock|

    screenLock := ScreenLock forDevice:Screen current.

    Delay waitForSeconds:1.

    screenLock checkTime.

    Delay waitForSeconds:12.

    screenLock checkTime.

    Delay waitForSeconds:3.

    screenLock unlock.

    screenLock unlisten.

                                                                [exEnd]

                                                                [exBegin]

    |screenLock channel running|

    screenLock := ScreenLock forDevice:Screen current.

    screenLock lockAfterSeconds:4.

    [

        channel := false asValue.

        channel onChangeEvaluate:[

            channel value ifTrue:[

                self information:'Application is locked\\Hit ok to unlock' withCRs.

                channel value:false.

            ].

        ].

        screenLock lockChannel:channel.

        [

            Delay waitForSeconds:2.

            screenLock checkTime.

        ] loop.

    ] valueNowOrOnUnwindDo:[

        screenLock unlisten.

    ].

                                                                [exEnd]

"

! !

!ScreenLock class methodsFor:'instance creation'!

forDevice:aWorkstation

    ^ self new initializeForDevice:aWorkstation

! !

!ScreenLock methodsFor:'accessing'!

lockAfterSeconds

    "return the value of the instance variable 'lockAfterSeconds' (automatically generated)"

    ^ lockAfterSeconds

!

lockAfterSeconds:something

    "set the value of the instance variable 'lockAfterSeconds' (automatically generated)"

    lockAfterSeconds := something.

!

lockChannel

    lockChannel isNil ifTrue:[

        self lockChannel:false asValue.

    ].

    ^ lockChannel

!

lockChannel:something

    lockChannel notNil ifTrue:[ 

        lockChannel removeDependent:self.

    ].

    lockChannel := something.

    lockChannel addDependent:self.

!

lockChannelOut

    lockChannelOut isNil ifTrue:[

        lockChannelOut := false asValue.

    ].

    ^ lockChannelOut

!

lockChannelOut:something

    "set the value of the instance variable 'lockChannelOut' (automatically generated)"

    lockChannelOut := something.

!

processor

    "return the value of the instance variable 'processor' (automatically generated)"

    ^ processor

!

processor:something

    "set the value of the instance variable 'processor' (automatically generated)"

    processor := something.

!

workstation

    "return the value of the instance variable 'workstation' (automatically generated)"

    ^ workstation

!

workstation:something

    "set the value of the instance variable 'workstation' (automatically generated)"

    workstation := something.

! !

!ScreenLock methodsFor:'change & update'!

update:aspect with:param from:anObject

    |lock|

    anObject == lockChannel ifTrue:[

        aspect == #value ifTrue:[

            "/ lockChannel is a value holder

            lock := lockChannel value.

        ] ifFalse:[

            "/ lockChannel is a block or something else

            lock := param.

        ].

        "lock or unlock the screen

         If a processor is defined, let the processor perform the unlock,

         so that posssible Display errors do not affect the sender"

        lock == true ifTrue:[

            processor isNil ifTrue:[

                self lockScreen.

            ] ifFalse:[

                processor enqueueMessage:#lockScreen for:self arguments:#().

            ].

        ] ifFalse:[

            processor isNil ifTrue:[

                self unlockScreen.

            ] ifFalse:[

                processor enqueueMessage:#unlockScreen for:self arguments:#().

            ].

        ]

    ].

! !

!ScreenLock methodsFor:'events'!

buttonMotion:state x:x y:y view:aView

    ^ self gotEventForView:aView.

!

buttonMultiPress:button x:x y:y view:aView

    ^ self gotEventForView:aView.

!

buttonPress:button x:x y:y view:aView

    ^ self gotEventForView:aView.

!

buttonRelease:button x:x y:y view:aView

    ^ self gotEventForView:aView.

!

keyPress:key x:x y:y view:aView

    ^ self gotEventForView:aView.

!

keyRelease:key x:x y:y view:aView

    ^ self gotEventForView:aView.

!

mouseWheelMotion:state x:x y:y amount:amount deltaTime:dTime view:aView

    ^ self gotEventForView:aView.

! !

!ScreenLock methodsFor:'lock interface'!

checkTime

    |now|

    lockedViews isNil ifTrue:[

        now := Timestamp now.

        lastInactiveTime notNil ifTrue:[

            (lastInactiveTime addSeconds:lockAfterSeconds value) < now ifTrue:[

                self lock

            ].

        ] ifFalse:[

            lastInactiveTime := now.

        ].

    ].

!

lock

   "trigger locking of screen"

    self lockChannel value:true.

!

unlisten

    "do not listen for events any longer.

     This must be called when a screen lock is detached from a

     screen."

    workstation removeEventListener:self

!

unlock

   "trigger unlocking of screen"

    self lockChannel value:false.

! !

!ScreenLock methodsFor:'private'!

gotEventForView:v

    "got an event.

     Reset the inactive timer.

     If locked, eat all user events (for security)"

    lockedViews isNil ifTrue:[

        lastInactiveTime := nil.        

        ^ false.

    ].

    ^ lockedViews includes:v.

!

initializeForDevice:aWorkstation

     lockAfterSeconds := 10.

     workstation := aWorkstation.

     workstation addEventListener:self.

!

lockScreen

    "lock the screen"

    lockedViews := workstation allViews.

    hiddenViews := lockedViews select:[:v|

        "close popupViews, they will leave the modal loop when 

         they are unmapped.

         This is a kludge, but invisible popUpViews are 

         currently not supported"

        v isPopUpView ifTrue:[

            v hide.

        ].

        v shown and:[v isTopView].

    ].

    hiddenViews do:[:v|

        v beInvisible.

    ].

    lockChannelOut notNil ifTrue:[      

        lockChannelOut value:true.

    ].

!

unlockScreen

    lastInactiveTime := nil.

    hiddenViews do:[:v|

        "don't try to restore views that have been closed while

         being invisible"

        v id notNil ifTrue:[

            v beVisible.

        ].

    ].

    hiddenViews := lockedViews := nil.

    lockChannelOut notNil ifTrue:[      

        lockChannelOut value:false.

    ].

! !

!ScreenLock methodsFor:'queries'!

isLocked

    ^ lockedViews notNil

! !

!ScreenLock class methodsFor:'documentation'!

version

    ^ '$Header: /cvs/stx/stx/libview2/ScreenLock.st,v 1.7 2004-03-20 19:20:31 stefan Exp $'

! !