"

 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.

"

CompiledCode subclass:#Method

	instanceVariableNames:'source sourcePosition category package'

	classVariableNames:'PrivateMethodSignal LastFileReference LastSourceFileName

		LastWhoClass'

	poolDictionaries:''

	category:'Kernel-Methods'

!

!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 a subclass 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

    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

"

!

dynamicMethods

"

    On systems which support dynamic loading of 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.

"

!

privacy 

"

    ST/X includes an EXPERIMENTAL implementation of method privacy.

    Individual methods may be set to private or protected via the

    #setPrivate and #setProtected 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 or super-send

    from the superclass, the class itself or subclasses.

    Protected methods may not be called from subclasses, 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 interface 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 ;-)

"

! !

!Method class methodsFor:'initialization'!

initialize

    PrivateMethodSignal isNil ifTrue:[

	"EXPERIMENTAL"

	PrivateMethodSignal := ExecutionErrorSignal newSignalMayProceed:true.

	PrivateMethodSignal nameClass:self message:#privateMethodSignal.

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

    ]

! !

!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:[

	source := manager nextObject.

    ].

    code := manager nextObject.

    snapId == ObjectMemory snapshotID ifTrue:[

	ObjectMemory incrementSnapshotID

    ].

    m := Method basicNew.

    cat notNil ifTrue:[m category:cat].

    m flags:flags.

    m literals:lits.

    m byteCode:code.

    sourcePos isNil ifTrue:[

	m source:source

    ] ifFalse:[

	m sourceFilename:sourceFilename position:sourcePos

    ].

    ^ m

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

! !

!Method class methodsFor:'queries'!

isBuiltInClass

    "this class is known by the run-time-system"

    ^ self == Method

!

maxNumberOfArguments

    "this limit will be removed in one of the next versions ..."

    ^ 15  "cannot be easily changed; should ask the VM about this number"

!

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

%}

! !

!Method class methodsFor:'special'!

flushSourceStreamCache

    LastSourceFileName := nil

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

! !

!Method methodsFor:'accessing'!

category

    "return the methods category or nil"

    ^ category

!

category:aStringOrSymbol

    "set the methods category"

    category := aStringOrSymbol asSymbol

!

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 stream|

    src := self source.

    src isNil ifTrue:[^ nil].

    stream := ReadStream on:src.

    (stream skipThrough:Character doubleQuote) isNil ifTrue:[^ nil].

    ^ stream upTo:Character doubleQuote.

    "

     (Method compiledMethodAt:#comment) comment 

    "

!

flags

    "return the flags (number of method variables, stacksize etc.).

     Dont depend on the values in the flag field - it may change

     without notice."

    ^ flags

!

flags:newFlags

    "set the flags (number of method variables, stacksize).

     WARNING: for internal use by the compiler only."

    "protect myself a bit - putting in an object would crash me ..."

    (newFlags isMemberOf:SmallInteger) ifTrue:[

	flags := newFlags

    ]

!

getSource

    ^ source

!

isIgnored

    "return true, if this is an ignored method.

     Ignored methods are physically present in the source file,

     but no code is generated for it by stc, and the VM does not see

     it in its message lookup.

     (i.e. setting a method to #ignored, and sending that selector,

      leads to either the superclasses implementation to be called, 

      or a doesNotUnderstand exception to be raised)

     Notice: this is a nonstandard feature, not supported

     by other smalltalk implementations and not specified in the ANSI spec.

     This is EXPERIMENTAL - and being evaluated for usability.

     It may change or even vanish (if it shows to be not useful)."

%{  /* NOCONTEXT */

#if defined(F_IGNORED) && defined(M_PRIVACY)

    int f = _intVal(_INST(flags));

    if ((f & M_PRIVACY) == F_IGNORED) {

	RETURN (true);

    }

#endif

%}.

    ^ false

!

isPrivate

    "return true, if this is a private method.

     Execution of private methods is only allowed via self/super sends

     from superclasses, the class itself or subclasses.

     If a private method is called by some other class, a runtime

     error (PrivateMethodSignal) is raised.

     Notice: method privacy is a nonstandard feature, not supported

     by other smalltalk implementations and not specified in the ANSI spec.

     This is EXPERIMENTAL - and being evaluated for usability.

     It may change or even vanish (if it shows to be not useful)."

%{  /* NOCONTEXT */

    /* I made this a primitive to get the define constant from stc.h */

#if defined(F_PRIVATE) && defined(M_PRIVACY)

    int f = _intVal(_INST(flags));

    if ((f & M_PRIVACY) == F_PRIVATE) {

	RETURN (true);

    }

#endif

%}.

    ^ false

!

isProtected

    "return true, if this is a protected method.

     Execution of protected methods is only allowed via self sends

     from superclasses or the class itself.

     If a protected method is called by some other class, a runtime

     error (PrivateMethodSignal) is raised.

     Notice: method privacy is a nonstandard feature, not supported

     by other smalltalk implementations and not specified in the ANSI spec.

     This is EXPERIMENTAL - and being evaluated for usability.

     It may change or even vanish (if it shows to be not useful)."

%{  /* NOCONTEXT */

    /* I made this a primitive to get the define constant from stc.h */

#if defined(F_CLASSPRIVATE) && defined(M_PRIVACY)

    int f = _intVal(_INST(flags));

    if ((f & M_PRIVACY) == F_CLASSPRIVATE) {

	RETURN (true);

    }

#endif

%}.

    ^ false

!

isPublic

    "return true, if this is a public method - I.e. can be executed via any send.

     This is the default and how other smalltalk implementations treat all methods.

     Notice: method privacy is a nonstandard feature, not supported

     by other smalltalk implementations and not specified in the ANSI spec.

     This is EXPERIMENTAL - and being evaluated for usability.

     It may change or even vanish (if it shows to be not useful)."

%{  /* NOCONTEXT */

    /* I made this a primitive to get the define constant from stc.h */

#if defined(M_PRIVACY) && (defined(F_PRIVATE) || defined(F_CLASSPRIVATE) || defined(F_IGNORED))

    int f = _intVal(_INST(flags));

# ifdef F_PRIVATE

    if ((f & M_PRIVACY) == F_PRIVATE) {

	RETURN (false);

    }

# endif

# ifdef F_CLASSPRIVATE

    if ((f & M_PRIVACY) == F_CLASSPRIVATE) {

	RETURN (false);

    }

# endif

# ifdef F_IGNORED

    if ((f & M_PRIVACY) == F_IGNORED) {

	RETURN (false);

    }

# endif

#endif

%}.

    ^ true

!

isRestricted

    "return the flag bit stating that this method is restricted.

     Execution of the receiver will only be allowed if the system is not in

     'trap restricted mode' (-->ObjectMemory) otherise a runtime 

     error (PrivateMethodSignal) is raised.

     Notice: method restriction is a nonstandard feature, not supported

     by other smalltalk implementations and not specified in the ANSI spec.

     This is EXPERIMENTAL - and being evaluated for usability.

     It may change or even vanish (if it shows to be not useful)."

%{  /* NOCONTEXT */

#ifdef F_RESTRICTED

    int f = _intVal(_INST(flags));

    if (f & F_RESTRICTED) {

	RETURN (true);

    }

#endif

%}.

    ^ false

!

numberOfMethodArgs

    "return the number of arguments, the method expects." 

%{  /* NOCONTEXT */

    /* made this a primitive to get define in stc.h */

#ifdef F_NARGS

    RETURN (_MKSMALLINT((_intVal(_INST(flags)) & F_NARGS) >> F_NARGSHIFT));

#endif

%}

.

    "

     The old implementation simply counted the arguments from

     the methods source - new versions include this information

     in the flag instVar, for more security in #perform:

    "

    ^ self methodArgNames size

!

numberOfMethodArgs:aNumber

    "currently, the number of arguments is NOT remembered in

     methods, but this will be added soon to allow for more checking

     in #perform:.

     The limitation in the max. number of arguments is due to the

     missing SENDxx functions in the VM and cases in #perform. This too 

     will be removed in a later release, allowing any number of arguments.

     - for use by compiler only."

    (aNumber between:0 and:self class maxNumberOfArguments) ifFalse:[

	self error:('ST/X only supports up to a maximum of ' ,

		    self class maxNumberOfArguments printString ,

		    ' method arguments').

	^ self

    ].

%{

    /* made this a primitive to get define in stc.h */

#ifdef F_NARGS