"

stx:libscm - a new source code management library for Smalltalk/X

Copyright (C) 2012-2015 Jan Vrany

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Lesser General Public

License as published by the Free Software Foundation; either

version 2.1 of the License. 

This library is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public

License along with this library; if not, write to the Free Software

Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

"

"{ Package: 'stx:libscm/common' }"

Object subclass:#SCMCodeMonitor

	instanceVariableNames:'sequenceNumber'

	classVariableNames:'Current SequenceNumberMax'

	poolDictionaries:''

	category:'SCM-Common-StX'

!

!SCMCodeMonitor class methodsFor:'documentation'!

copyright

"

stx:libscm - a new source code management library for Smalltalk/X

Copyright (C) 2012-2015 Jan Vrany

This library is free software; you can redistribute it and/or

modify it under the terms of the GNU Lesser General Public

License as published by the Free Software Foundation; either

version 2.1 of the License. 

This library is distributed in the hope that it will be useful,

but WITHOUT ANY WARRANTY; without even the implied warranty of

MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public

License along with this library; if not, write to the Free Software

Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

"

!

documentation

"

    SCMCodeMonitor is helper class that monitors code changes

    in Smalltalk. Upon each change (class or method added/removed/moved

    to package/...) it increases internal sequenceNumber.

    Client may use that sequence number to check whether some

    cached data are still valid - they should be considered

    out-of-date if sequence number from monitor differs from

    sequence number remembered when cached value has been 

    computed.

    [author:]

        Jan Vrany <jan.vrany@fit.cvut.cz>

    [instance variables:]

    [class variables:]

    [see also:]

"

! !

!SCMCodeMonitor class methodsFor:'initialization'!

initialize

    "Invoked at system start or when the class is dynamically loaded."

    "/ please change as required (and remove this comment)

    SequenceNumberMax := SmallInteger maxVal

    "Modified: / 28-02-2014 / 23:25:01 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!SCMCodeMonitor class methodsFor:'instance creation'!

new

    "return an initialized instance"

    ^ self basicNew initialize.

! !

!SCMCodeMonitor class methodsFor:'accessing'!

sequenceNumber

    Current isNil ifTrue:[ 

        Current := self new.

    ].

    ^ Current sequenceNumber

    "Created: / 28-02-2014 / 23:23:26 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!SCMCodeMonitor methodsFor:'accessing'!

sequenceNumber

    ^ sequenceNumber

    "Created: / 28-02-2014 / 23:29:17 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!SCMCodeMonitor methodsFor:'change & update'!

update:something with:aParameter from:changedObject

    "Invoked when an object that I depend upon sends a change notification."

    ((something == #methodInClass) 

        or:[ something == #projectOrganization

        or:[ something == #classRemove 

        or:[ something == #newClass ]]]

    ) ifTrue:[ 

        sequenceNumber := sequenceNumber == SequenceNumberMax ifTrue:[0] ifFalse:[sequenceNumber := sequenceNumber + 1].

        ^ self

    ].

    ^ self

"/    Transcript showCR: '>> ', something

    "Modified: / 01-03-2014 / 00:13:17 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

!SCMCodeMonitor methodsFor:'initialization'!

initialize

    "Invoked when a new instance is created."

    sequenceNumber := 0.

    Smalltalk addDependent: self.  

    "/ super initialize.   -- commented since inherited method does nothing

    "Modified: / 28-02-2014 / 23:25:14 / Jan Vrany <jan.vrany@fit.cvut.cz>"

! !

SCMCodeMonitor initialize!