"

 COPYRIGHT (c) 1991 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

nil subclass:#Autoload

	instanceVariableNames:''

	classVariableNames:'LazyLoading AutoloadFailedSignal LoadedClasses'

	poolDictionaries:''

	category:'Kernel-Classes'

!

!Autoload class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1991 by Claus Gittinger

	      All Rights Reserved

 This software is furnished under a license and may be used

 only in accordance with the terms of that license and with the

 inclusion of the above copyright notice.   This software may not

 be provided or otherwise made available to, or used by, any

 other person.  No title to or ownership of the software is

 hereby transferred.

"

!

documentation

"

    In memory limited systems (as my 8Mb 386 is) all seldom-used classes are made

    subclasses of this class. 

    Autoload catches all messages and files-In the corresponding code

    when first used. 

    Then the caught message is resent to the (now existing) class.

    Class files are searched along the searchPath (see Smalltalk),

    and any of binary-classFile, byteCode-classFile or sourceFile are

    loaded, whichever is found first. For binaries to be loaded,

    these must be found in the 'bin' directory. Sources must be found

    in the 'source' directory.

    (Usually, Autoload classes finds the source file and loads that one).

    When started, the patches startup script arranges for the abbreviation

    file 'include/abbrev.stc' to be read and installs autoload stubs for

    all classes listed in that file, which do not exists already.

    The abbreviation file is maintained by the production environment

    and updated by makefile rules - therefore, it should not be edited

    manually.

    Late addition: above comment is no longer true - I have made now almost

    all Demos & Goodies be autoloaded ... even for big systems.

    [class variables:]

	LazyLoading             <Boolean>       if true, the loaded classes 

						methods will NOT be compiled at 

						autoload time, but instead when 

						first called. This allows for a 

						faster load. However, expect short 

						pauses later when the methods are

						first executed.

	AutoloadFailedSignal    <Signal>        signal raised if an autoloaded 

						classes source is not available.

	LoadedClasses           <Collection>    set of classes that heve been

						autoloaded (for later unload)

    [see also:]

	Smalltalk

    [author:]

	Claus Gittinger

"

! !

!Autoload class methodsFor:'initialization'!

initialize

    "initialize the failure-signal"

    AutoloadFailedSignal isNil ifTrue:[

	LazyLoading := false.

	AutoloadFailedSignal := Object errorSignal newSignalMayProceed:true.

	AutoloadFailedSignal nameClass:self message:#autoloadFailedSignal.

	AutoloadFailedSignal notifierString:'autoload failed '.

	self setSuperclass:nil.

	ObjectMemory flushCaches.

    ]

    "Modified: 20.5.1997 / 19:06:25 / cg"

! !

!Autoload class methodsFor:'Signal constants'!

autoloadFailedSignal

    "return the signal raised when an autoload fails"

    ^ AutoloadFailedSignal

! !

!Autoload class methodsFor:'adding/removing autoloaded classes'!

addClass:aClassName

    "given a name, install a corresponding autoload class stub for it"

    self addClass:aClassName inCategory:'autoloaded-Classes'

    "

     Autoload addClass:'Clock'

    "

    "Modified: 24.4.1996 / 19:54:16 / cg"

!

addClass:aClassName inCategory:aCategory

    "given a name, install a corresponding autoload class stub for it"

    |nameSymbol|

    nameSymbol := aClassName asSymbol.

    (Smalltalk at:nameSymbol) isNil ifTrue:[

	Autoload subclass:nameSymbol

	     instanceVariableNames:''

	     classVariableNames:''

	     poolDictionaries:''

	     category:aCategory.

    ]

    "

     Autoload addClass:'Clock' inCategory:'autoloaded-Demos'

    "

    "Modified: 24.4.1996 / 19:54:20 / cg"

!

removeClass:aClass

    "remove a class from the list of loaded classes"

    LoadedClasses remove:aClass ifAbsent:[]

    "Modified: 24.4.1996 / 19:54:35 / cg"

! !

!Autoload class methodsFor:'fileout'!

basicFileOutDefinitionOn:aStream withNameSpace:forceNameSpace

    "print an expression to define myself on aStream.

     Since autoloaded classes dont know their real definition, simply

     output some comment string making things clear in the browser."

    |myName fileName nm mgr classFileName packageDir|

    (self == Autoload) ifTrue:[^ super basicFileOutDefinitionOn:aStream withNameSpace:forceNameSpace].

    myName := self name.

    aStream nextPutAll:'"' ; nextPutLine:'Notice from Autoload:'; cr;

	    spaces:4; nextPutLine:myName , ' is not yet loaded.'; cr.

    aStream nextPutAll:'to load, execute: '.

    aStream cr; cr; spaces:4; nextPutLine:myName  , ' autoload'.

    aStream cr; nextPutLine:'or use the browsers load-function (in the class menu).'.

    "

     the following is simply informative ...

     actually, its a hack & kludge - there ought to be a method for this

     in Smalltalk 

     (knowing the details of loading here is no good coding style)

    "

    fileName := Smalltalk fileNameForClass:myName.

    (ObjectFileLoader notNil and:[Smalltalk loadBinaries]) ifTrue:[

	(nm := Smalltalk libraryFileNameOfClass:myName) notNil ifTrue:[

	    nm := nm , ' (a classLibrary, possibly including more classes)'

	] ifFalse:[

	    nm := Smalltalk getBinaryFileName:(fileName , '.so').

	    nm isNil ifTrue:[

		nm := Smalltalk getBinaryFileName:(fileName , '.o')

	    ].

	    nm notNil ifTrue:[

		nm := nm , ' (a classBinary)'

	    ]

	].

    ].

    nm isNil ifTrue:[

	nm := Smalltalk getFileInFileName:(fileName , '.st').

	nm isNil ifTrue:[

	    nm := Smalltalk getSourceFileName:(fileName , '.st').

	].

    ].

    nm notNil ifTrue:[

	aStream cr; nextPutLine:'When accessed, ' , myName , ' will automatically be loaded'.

	aStream nextPutLine:'from: '; spaces:4; nextPutAll:nm.

	nm asFilename isSymbolicLink ifTrue:[

	    aStream cr; cr.

	    aStream nextPutLine:'which is a link to: '; spaces:4; 

		    nextPutAll:(nm asFilename linkInfo path).

	]

    ] ifFalse:[

	aStream cr; nextPutLine:'There is currently no file to load ' , myName , ' from.'; cr.

	(mgr := Smalltalk at:#SourceCodeManager) notNil ifTrue:[

	    classFileName := Smalltalk fileNameForClass:myName.

	    packageDir := Smalltalk sourceDirectoryNameOfClass:myName.

	].

	(classFileName notNil and:[packageDir notNil]) ifTrue:[

	    aStream nextPutAll:'When accessed, I''ll ask the sourceCodeManager to load the code 

from "' , classFileName , '.st" in the "' , packageDir , '" package.'.

	] ifFalse:[

	    aStream nextPutAll:'When accessed, an error will be reported.'.

	]

    ].

    aStream cr; nextPutAll:'"'.

    "Modified: 30.12.1996 / 17:25:15 / cg"

    "Created: 5.1.1997 / 14:31:33 / cg"

! !

!Autoload class methodsFor:'lazy compilation'!

compileLazy

    "return the lazy loading flag - if on, fileIn is much faster,

     but pauses are to be expected later, since methods are compiled

     when first executed."

    ^ LazyLoading

!

compileLazy:aBoolean

    "turn on/off lazy loading - if on, fileIn is much faster,

     but pauses are to be expected later, since methods are compiled

     when first executed.

     If you like it, add a line to your startup file."

    LazyLoading := aBoolean

! !

!Autoload class methodsFor:'loading'!

autoload

    "use this to force loading

     - it is defined a noop in all non-autoloading classes"

    |mySelf myName myNameSpace newClass oldMeta project prevMode package|

    mySelf := self.

    myName := self name asSymbol.

    myNameSpace := self nameSpace.

    "remove myself - to avoid recompilation"

    Smalltalk at:myName put:nil.

    "load it"

    (Object infoPrinting and:[Smalltalk silentLoading ~~ true]) ifTrue:[

	Transcript showCR:('autoloading ', myName , ' ...'); endEntry.

    ].

    [

	prevMode := ClassCategoryReader sourceMode.

"/

"/ no- do not do this; it may lead to trouble ...

"/        ClassCategoryReader sourceMode:#reference.

	"/

	"/ in order to not get a package of private (or whatever),

	"/ temporarily set the currentProject to nil.

	"/ we will later set the classes package to something useful

	"/

	Project notNil ifTrue:[

	    project := Project current.

	    Project setProject:nil.

	].

	Class nameSpaceQuerySignal answer:myNameSpace "Smalltalk" 

	do:[

	].

	ClassCategoryReader sourceMode:prevMode.

	project notNil ifTrue:[

	    Project setProject:project.

	].

    ] valueOnUnwindDo:[

	ClassCategoryReader sourceMode:prevMode.

	project notNil ifTrue:[

	    Project setProject:project.

	].

	Smalltalk at:myName put:mySelf.

    ].

    "did it work ?"

    newClass := Smalltalk at:myName.

    Smalltalk at:myName put:mySelf.   "will be undone by become:"

    "no - report the error"

    newClass isNil ifTrue:[

	"

	 this signal is raised, if an autoloaded class

	 cannot be loaded. Usually, this happends when

	 some sourcefile is missing, not readable or if 

	 an entry is missing in the abbreviation file.

	 Check for a readable file named <myName>.st 

	 in the 'source' directory and (if its a long fileName) 

	 for a corresponding entry in the abbreviation file

	 'include/abbrev.stc'.

	 Finally, your searchpath could be set wrong -

	 both 'source' and 'include' directories must be found in

	 one of the directories named in systemPath.

	 In the debugger, press 'abort' to continue execution.

	" 

	AutoloadFailedSignal

	    raiseRequestWith:self

	    errorString:('autoload of ' , myName , ' failed').

	^ nil

    ].

    "/

    "/ autoloaded classes get their package from the revision (if present)

    "/ this only happens with autoloaded sourceFiles which have no package

    "/ info encoded. (binary classes have it)

    "/ If there is no such information, give it my package (if I have one)

    "/

    newClass setPackageFromRevision.

    (newClass package isNil 

    or:[newClass package = 'no package']) ifTrue:[

	package := self package.

	(package notNil and:[package ~= 'no package'])

	ifTrue:[

	    newClass setPackage:package.

	].

    ].

    LoadedClasses isNil ifTrue:[

	LoadedClasses := IdentitySet new.

    ].

    LoadedClasses add:newClass.

    "wow - it worked. now the big trick ..."

"/    newClass class setSoleInstance:self.   "/ will be undone by become ...

    oldMeta := self class.

self setName:(self name , ' (auto)').

    self becomeSameAs:newClass.

    oldMeta becomeSameAs:newClass class.

    ObjectMemory flushCaches.

    LoadedClasses rehash.

    (newClass class implements:#initialize) ifTrue:[

	newClass initialize.

    ].

    newClass privateClassesDo:[:aPrivateClass |

	(aPrivateClass class implements:#initialize) ifTrue:[

	    aPrivateClass initialize.

	]

    ].

    newClass postAutoload.

    ^ newClass

! !

!Autoload class methodsFor:'message catching'!

basicNew

    "catch basicNew - load the class and send it to the real one"

    ^ self doesNotUnderstand:(Message selector:#basicNew)

    "Modified: 24.4.1996 / 19:53:10 / cg"

!

basicNew:arg

    "catch basicNew: - load the class and send it to the real one"

    ^ self doesNotUnderstand:(Message selector:#basicNew: with:arg)

    "Modified: 24.4.1996 / 19:53:16 / cg"

!

comment

    "return the classes comment.

     Autoloaded classes have no comment; but I myself have one"

    (self == Autoload) ifTrue:[^ super comment].

    ^ 'not yet loaded'

!

doesNotUnderstand:aMessage

    "caught a message; load the class and retry the message"

    |newClass|

    self ~~ Autoload ifTrue:[

	newClass := self autoload.

	newClass notNil ifTrue:[

	    ^ newClass perform:(aMessage selector)

		 withArguments:(aMessage arguments)

	]

    ].

    ^ super doesNotUnderstand:aMessage

    "Modified: 24.4.1996 / 19:53:27 / cg"

!

new

    "catch new - load the class and resend #new to the real one"

    ^ self doesNotUnderstand:(Message selector:#new)

    "Modified: 26.5.1997 / 14:59:52 / cg"

!

new:arg

    "catch new: - load the class and resend #new: it to the real one"

    ^ self doesNotUnderstand:(Message selector:#new: with:arg)

    "Modified: 26.5.1997 / 14:59:58 / cg"

!

readFrom:aStream 

    "catch  - load the class and send it to the real one"

    ^ self doesNotUnderstand:(Message selector:#readFrom: with:aStream)

    "Created: 22.5.1996 / 23:44:23 / stefan"

!

readFrom:aStream onError:exceptionBlock

    "catch  - load the class and send it to the real one"

    ^ self doesNotUnderstand:(Message selector:#readFrom:onError: with:aStream with:exceptionBlock)

    "Created: 22.5.1996 / 23:03:39 / stefan"

!

readFromString:aString

    "catch  - load the class and send it to the real one"

    ^ self doesNotUnderstand:(Message selector:#readFromString: with:aString)

    "Created: 22.5.1996 / 23:46:15 / stefan"

!

readFromString:aString onError:exceptionBlock

    "catch  - load the class and send it to the real one"

    ^ self doesNotUnderstand:(Message selector:#readFromString:onError: with:aString with:exceptionBlock)

    "Created: 22.5.1996 / 23:04:49 / stefan"

!

respondsTo:aSelector

    "catch respondsTo: - load the class and resend #respondsTo: it to the real one"

    self == Autoload ifTrue:[

	^ super respondsTo:aSelector

    ].

    ^ self doesNotUnderstand:(Message selector:#respondsTo: with:aSelector)

    "Modified: 26.5.1997 / 14:59:58 / cg"

!

subclass:nameSymbol instanceVariableNames:instVarNames classVariableNames:cVarNames poolDictionaries:pools category:cat