"

 COPYRIGHT (c) 1989 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.

"

"{ Package: 'stx:libbasic' }"

CompiledCode variableSubclass:#Method

	instanceVariableNames:'source sourcePosition category package mclass'

	classVariableNames:'PrivateMethodSignal LastFileReference LastSourceFileName

		LastWhoClass LastFileLock LastMethodSources CompilationLock'

	poolDictionaries:''

	category:'Kernel-Methods'

!

Object subclass:#MethodWhoInfo

	instanceVariableNames:'myClass mySelector'

	classVariableNames:''

	poolDictionaries:''

	privateIn:Method

!

!Method class methodsFor:'documentation'!

copyright

"

 COPYRIGHT (c) 1989 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

"

    this class defines protocol for executable methods;

    both compiled and interpreted methods are represented by this class.

    Compiled methods have a non-nil code field, while interpreted methods have

    a nil code field and non-nil byteCode field.

    If there are both non-nil code and bytecode fields, the VM will execute

    the machine-code of a method. If both are nil when executed, a noByteCode

    message is sent by the VM to the method where a signal is raised.

    The methods sourcecode is represented by source and sourcePosition:

    - if sourcePosition is a Number, the source-field is the fileName and

      sourcePosition is the character offset of the source-chunk in this source file.

    - If sourcePosition is nil, the source is the string in the source field.

    (an old version used ExternalString instances here, but that lead to

     10000 additional little objects ...)

    The flags field defines things like the number of method-locals,

    method arguments and stack requirements (for interpreted methods).

    Do not depend on any value in the flags field - it may change without

    notice.

    Notice, that in ST/X, method can be subclassed; executable code is

    identified not by being an instance of Block or Method, but instead by

    having the executable flag bit set in the class. The VM can execute anything

    which is identified as executable (assuming that the first instance variable

    is the machine-code address) - this allows for easy future extension.

    [Instance variables:]

	source          <String>        the source itself (if sourcePosition isNil)

					or the fileName where the source is found

	sourcePosition  <Integer>       the position of the methods chunk in the file

	category        <Symbol>        the methods category

	package         <Symbol>        the package, in which the methods was defined

	mclass          <Class>         the class in which I am defined

	indexed slots                   literals

    [Class variables:]

	PrivateMethodSignal             raised on privacy violation (see docu)

	LastFileReference               weak reference to the last sourceFile

	LastSourceFileName              to speedup source access via NFS

    WARNING: layout known by compiler and runtime system - dont change

    [author:]

	Claus Gittinger

"

!

dynamicMethods

"

    On systems which support dynamic loading of stc-compiled machine code (SYS5.4, Linux),

    methods may now be compiled to machine code from within the browser,

    and the resulting machine code object be loaded in.

    The ObjectFileLoader keeps (weak) handles to the resulting methods and

    invalidates the corresponding method objects, if the underlying methods

    object code is unloaded.

    Invalid methods will trap into the debugger when executed;

    also, the browser marks them as '(* not executable *)' in its method list.

    Notice: this has nothing to do with JIT compilation, which is always possible.

    JIT-compilation is done from bytecodes to a machineCode cache.

    In contrast, dynamic loading of stc-compiled code goes via intermediate C-code

    which is compiled by the machines native C-compiler.

    As opposed to JITted code, this allows for embedded primitive C-code.

"

!

privacy 

"

    ST/X includes an EXPERIMENTAL implementation of method privacy.

    Individual methods may be set to private or protected via the

    privacy:#private and privacy:#protected messages. Also, categories may be

    filedIn as a whole as private using #privateMethodsFor: or as

    protected using #protectedMethodsFor: instead of the well known #methodsFor:.

    The additional #publicMethodsFor: is for documentation purposes, and

    is equivalent to #methodsFor: (also to support fileIn of ENVY methods).

    Private methods may be executed only when called via a self-send

    from the superclass-methods and self or super-sends from methods in the

    class itself or subclasses.

    Protected methods may not be called from subclasses-methods, 

    i.e. they may only be called via self sends from within the current class.

    (i.e. private methods are less private than protected ones)

    When such a situation arises, the VM (runtime system) will raise the

    PrivateMethodSignal exception (if nonNil), which usually brings you into the

    debugger.

    If PrivateMethodSignal is nil, the VM will not check for this, and

    execution is as usual. (you may want to nil-it for production code,

    and leave it non nil during development).

    NOTICE: there is no (not yet ?) standard defined for method privacy,

    however, the definition protocol was designed to be somewhat ENVY compatible 

    (from what can be deduced by reading PD code).

    Also, the usability of privacy is still to be tested.

    This interface, the implementation and the rules for when a privacy violation

    may change (in case of some ANSI standard being defined).

    Be warned and send me suggestions & critics (constructive ;-)

    Late note (Feb 2000):

	the privacy feature has new been in ST/X for some years and was NOT heavily

	used - neither at eXept, nor by customers.

	In Smalltalk, it seems to be a very questionable feature, actually limiting

	code reusability.

	The privacy features are left in the system to demonstrate that it can be

	done in Smalltalk (for religious C++ fans ... to avoid useless discussions)

	(the check is not expensive, w.r.t. the VM runtime behavior).

"

! !

!Method class methodsFor:'initialization'!

initialize

    "create signals"

    PrivateMethodSignal isNil ifTrue:[

	"EXPERIMENTAL"

	PrivateMethodSignal := ExecutionErrorSignal newSignalMayProceed:true.

	PrivateMethodSignal nameClass:self message:#privateMethodSignal.

	PrivateMethodSignal notifierString:'attempt to execute private/protected method'.

    ].

    LastFileLock isNil ifTrue:[

	LastFileLock := Semaphore forMutualExclusion name:'LastFileLock'.

	LastFileReference := WeakArray new:1.

	LastFileReference at:1 put:0.

    ].

    CompilationLock := RecursionLock new name:'MethodCompilation'.

    "Modified: 22.4.1996 / 16:34:38 / cg"

    "Modified: 3.1.1997 / 16:58:16 / stefan"

! !

!Method class methodsFor:'Signal constants'!

privateMethodSignal

    "return the signal raised when a private/protected method is called

     by some other object (i.e. not a self- or super send)"

    ^ PrivateMethodSignal

! !

!Method class methodsFor:'binary storage'!

binaryDefinitionFrom: stream manager: manager

    "read my definition from stream."

    |cls sel|

    "type-byte"

    stream nextByte == 0 ifTrue:[

	"

	 built-in method

	"

	cls := manager nextObject.

	sel := manager nextObject.

	"

	 mhmh - on the source system, this was a machinecode

	 method, while here its an interpreted one ...

	"

	cls isLoaded ifFalse:[

	    cls autoload

	].

	^ cls compiledMethodAt:sel

    ].

    "

     bytecode method

    "

    ^ super binaryDefinitionFrom:stream manager:manager

!

binaryFullDefinitionFrom:stream manager:manager

    "retrieve a full bytecoded-method."

    |snapId cat flags code lits m sourceFilename sourcePos source|

    snapId := manager nextObject.

    cat := manager nextObject.

    flags := manager nextObject.

    lits := manager nextObject.

    sourceFilename := manager nextObject.

    sourcePos := manager nextObject.

    sourcePos isNil ifTrue:[

    ].

    code := manager nextObject.

    snapId == ObjectMemory snapshotID ifTrue:[

    ].

    m := Method basicNew:(lits size).

    m flags:flags.

    m literals:lits.

    m byteCode:code.

    sourcePos isNil ifTrue:[

    ] ifFalse:[

    ].

    ^ m

    "Created: 16.1.1996 / 14:44:08 / cg"

    "Modified: 24.6.1996 / 12:29:35 / stefan"

    "Modified: 5.1.1997 / 01:09:56 / cg"

! !

!Method class methodsFor:'queries'!

isBuiltInClass

    "return true if this class is known by the run-time-system.

     Here, true is returned for myself, false for subclasses."

    ^ self == Method

    "Modified: 23.4.1996 / 15:59:50 / cg"

!

methodPrivacySupported

    "return true, if the system was compiled to support methodPrivacy.

     You should not depend on that feature being available."

%{  /* NOCONTEXT */

#if defined(F_PRIVATE) || defined(F_CLASSPRIVATE)

    RETURN (true);

#else

    RETURN (false);

#endif

%}

!

resourceTypes

    "get the types of resources for which a spec definition and corresponding editor exist"

    ^#(canvas menu image fileImage help hierarchicalList tabList tableColumns)

! !

!Method class methodsFor:'special'!

flushSourceStreamCache

    LastSourceFileName := LastMethodSources := nil

    "Created: 9.2.1996 / 19:05:28 / cg"

"

self flushSourceStreamCache

"

! !

!Method methodsFor:'accessing'!

category

    "return the methods category or nil"

    ^ category

!

category:aStringOrSymbol

    "set the methods category"

    aStringOrSymbol notNil ifTrue:[

    ]

    "Modified: / 13.11.1998 / 23:55:05 / cg"

!

comment

    "return the methods comment.

     This is done by searching for and returning the first comment

     from the methods source (excluding any double-quotes). 

     Returns nil if there is no comment (or source is not available)."

    |src comment comments parser|

    src := self source.

    src isNil ifTrue:[^ nil].

    parser := Parser for:src in:nil.

    parser ignoreErrors; ignoreWarnings; saveComments:true.

    parser parseMethodSpec.

    comments := parser comments.

    comments size ~~ 0 ifTrue:[

	comment := comments first string.

	(comment withoutSpaces endsWith:'}') ifTrue:[

	    "if first comment is a pragma, take next comment"

	    comment := comments at:2 ifAbsent:nil.

	    comment notNil ifTrue:[

		comment := comment string.

	    ].

	].

    ].

    ^ comment.

    "

     (Method compiledMethodAt:#comment) comment  

     (Object class compiledMethodAt:#infoPrinting:) comment  

    "

    "Modified: / 17.2.1998 / 14:50:00 / cg"

    "Modified: / 23.2.1998 / 10:26:08 / stefan"

!

getSource

    "low-level access to the source instance-variable.

     For internal (compiler) use only.

     This is NOT always the methods source string"

    ^ source

!

getSourcePosition

    "low-level access to the sourcePosition instance-variable.

     For internal (compiler) use only.

     This is NOT always the methods sourcePosition"

    ^ sourcePosition

!

localSourceFilename:aFileName position:aNumber

    "set the methods sourcefile/position indicating, that 

     this is a local file."

    source := aFileName.

    sourcePosition := aNumber negated

    "Created: 16.1.1997 / 01:25:52 / cg"

!

localSourceStream

    "try to open a stream from a local source file,

     searching in standard places."

    |fileName aStream|

    package notNil ifTrue:[

	fileName := Smalltalk getSourceFileName:(package copyReplaceAll:$: with:$/) , '/' , source.

	fileName notNil ifTrue:[

	    aStream := fileName asFilename readStream.

	    aStream notNil ifTrue:[^ aStream].

	].

    ].

    fileName := Smalltalk getSourceFileName:source.

    fileName notNil ifTrue:[

	aStream := fileName asFilename readStream.

	aStream notNil ifTrue:[^ aStream].

    ].

    ^ nil

!

makeLocalStringSource

    "assure that the methods source code is stored locally as a string

     within the method (as opposed to an external string, which is accessed

     by reading the source code file).

     This is required, when a methods package is changed, to assure that its

     sourceCode is not lost."

    source notNil ifTrue:[

	sourcePosition notNil ifTrue:[

	    self source:(self source)

	]

    ].

!

mclass:aClass

    (mclass notNil and:[aClass notNil]) ifTrue:[

        'Method [warning]: mclass already set' errorPrintCR.

    ].

    mclass := aClass.

!

package

    "return the package-symbol"

    |cls|

    package notNil ifTrue:[ ^ package ].

    (cls := self mclass) isNil ifTrue:[

	^ ''

    ].

    ^ cls package ? ''

    "Modified: / 29.12.1998 / 01:16:05 / cg"

!

package:aSymbol

    "set the package-symbol"

    self makeLocalStringSource.

    package := aSymbol

!

setPackage:aSymbol

    "set the package-symbol"

    package := aSymbol

!

source

    "return the sourcestring for the receiver"

    |aStream fileName junk who myClass mgr className|

    "

     if sourcePosition is nonNil, its the fileName and

     abs(sourcePosition) is the offset.

     Otherwise, source is the real source

    "

    sourcePosition isNil ifTrue:[^ source].