/usr/share/gnu-smalltalk/kernel/Metaclass.st is in gnu-smalltalk-common 3.2.5-1.
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|
| Metaclass Method Definitions
|
|
======================================================================"
"======================================================================
|
| Copyright 1988,92,94,95,99,2000,2001,2002,2005,2007,2008,2009
| Free Software Foundation, Inc.
| Written by Steve Byrne, Brad Diller and Paolo Bonzini.
|
| This file is part of the GNU Smalltalk class library.
|
| The GNU Smalltalk class 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, or (at
| your option) any later version.
|
| The GNU Smalltalk class 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 the GNU Smalltalk class library; see the file COPYING.LIB.
| If not, write to the Free Software Foundation, 59 Temple Place - Suite
| 330, Boston, MA 02110-1301, USA.
|
======================================================================"
ClassDescription subclass: Metaclass [
| instanceClass |
<category: 'Language-Implementation'>
<comment: 'I am the root of the class hierarchy. My instances are metaclasses, one for
each real class. My instances have a single instance, which they hold
onto, which is the class that they are the metaclass of. I provide methods
for creation of actual class objects from metaclass object, and the creation
of metaclass objects, which are my instances. If this is confusing to you,
it should be...the Smalltalk metaclass system is strange and complex.'>
Metaclass class >> subclassOf: superMeta [
"Answer a new metaclass representing a subclass of superMeta"
<category: 'instance creation'>
| newMeta |
newMeta := self new.
newMeta superclass: superMeta.
superMeta addSubclass: newMeta.
newMeta initMetaclass: superMeta.
^newMeta
]
addClassVarName: aString [
"Add a class variable with the given name to the class pool dictionary"
<category: 'delegation'>
^self instanceClass addClassVarName: aString
]
removeClassVarName: aString [
"Removes the class variable from the class, error if not present, or
still in use."
<category: 'delegation'>
^self instanceClass removeClassVarName: aString
]
name [
"Answer the class name - it has none, actually"
<category: 'delegation'>
^nil
]
allSharedPoolDictionariesDo: aBlock [
"Answer the shared pools visible from methods in the metaclass,
in the correct search order."
<category: 'delegation'>
self asClass allSharedPoolDictionariesDo: aBlock
]
category [
"Answer the class category"
<category: 'delegation'>
^self asClass category
]
comment [
"Answer the class comment"
<category: 'delegation'>
^self asClass comment
]
environment [
"Answer the namespace in which the receiver is implemented"
<category: 'delegation'>
^self asClass environment
]
classPool [
"Answer the class pool dictionary"
<category: 'delegation'>
^self instanceClass classPool
]
classVarNames [
"Answer the names of the variables in the class pool dictionary"
<category: 'delegation'>
^self instanceClass classVarNames
]
debuggerClass [
"Answer the debugger class that was set in the instance class"
<category: 'delegation'>
^self instanceClass debuggerClass
]
allClassVarNames [
"Answer the names of the variables in the receiver's class pool dictionary
and in each of the superclasses' class pool dictionaries"
<category: 'delegation'>
^self instanceClass allClassVarNames
]
addSharedPool: aDictionary [
"Add the given shared pool to the list of the class' pool dictionaries"
<category: 'delegation'>
^self instanceClass addSharedPool: aDictionary
]
removeSharedPool: aDictionary [
"Remove the given dictionary to the list of the class' pool dictionaries"
<category: 'delegation'>
^self instanceClass removeSharedPool: aDictionary
]
sharedPools [
"Return the names of the shared pools defined by the class"
<category: 'delegation'>
^self instanceClass sharedPools
]
allSharedPools [
"Return the names of the shared pools defined by the class and any of
its superclasses"
<category: 'delegation'>
^self instanceClass allSharedPools
]
pragmaHandlerFor: aSymbol [
"Answer the (possibly inherited) registered handler for pragma
aSymbol, or nil if not found."
<category: 'delegation'>
^self instanceClass pragmaHandlerFor: aSymbol
]
name: className environment: aNamespace subclassOf: theSuperclass [
"Private - create a full featured class and install it, or change the
superclass or shape of an existing one; instance variable names,
class variable names and pool dictionaries are left untouched."
<category: 'basic'>
| aClass variableArray inheritedShape |
variableArray := theSuperclass notNil
ifTrue: [theSuperclass allInstVarNames]
ifFalse: [#()].
"Look for an existing metaclass"
aClass := aNamespace hereAt: className ifAbsent: [nil].
aClass isNil
ifTrue:
[^self
newMeta: className
environment: aNamespace
subclassOf: theSuperclass
instanceVariableArray: variableArray
shape: (theSuperclass isNil
ifTrue: [ nil ]
ifFalse: [ theSuperclass inheritShape ifTrue: [ #inherit ] ])
classPool: BindingDictionary new
poolDictionaries: #()
category: nil].
variableArray := variableArray , aClass instVarNames.
^self
name: className
environment: aNamespace
subclassOf: theSuperclass
instanceVariableArray: variableArray
shape: aClass shape
classPool: aClass classPool
poolDictionaries: aClass sharedPoolDictionaries
category: aClass category
]
name: newName environment: aNamespace subclassOf: theSuperclass instanceVariableNames: stringOfInstVarNames shape: shape classVariableNames: stringOfClassVarNames poolDictionaries: stringOfPoolNames category: categoryName [
"Private - parse the instance and class variables, and the pool
dictionaries, then create the class."
<category: 'basic'>
"Inherit instance variables from parent"
| variableArray classVarDict sharedPoolNames |
variableArray := self parseInstanceVariableString: stringOfInstVarNames.
variableArray := theSuperclass notNil
ifTrue: [theSuperclass allInstVarNames , variableArray]
ifFalse: [variableArray].
classVarDict := self parse: stringOfClassVarNames
toDictionary: BindingDictionary new.
sharedPoolNames := self parsePools: stringOfPoolNames in: aNamespace.
^self
name: newName asSymbol
environment: aNamespace
subclassOf: theSuperclass
instanceVariableArray: variableArray
shape: shape
classPool: classVarDict
poolDictionaries: sharedPoolNames
category: categoryName
]
name: className environment: aNamespace subclassOf: newSuperclass instanceVariableArray: variableArray shape: shape classPool: classVarDict poolDictionaries: sharedPoolNames category: categoryName [
"Private - create a full featured class and install it, or change an
existing one"
<category: 'basic'>
| aClass realShape needToRecompileMetaclasses needToRecompileClasses |
realShape := shape == #word
ifTrue: [CSymbols.CLongSize = 4 ifTrue: [#uint] ifFalse: [#uint64]]
ifFalse: [shape].
"Look for an existing metaclass"
aClass := aNamespace hereAt: className ifAbsent: [nil].
aClass isNil
ifTrue:
[^self
newMeta: className
environment: aNamespace
subclassOf: newSuperclass
instanceVariableArray: variableArray
shape: realShape
classPool: classVarDict
poolDictionaries: sharedPoolNames
category: categoryName].
aClass isVariable & realShape notNil
ifTrue:
[aClass shape == realShape
ifFalse:
[SystemExceptions.MutationError
signal: 'Cannot change shape of variable class']].
newSuperclass isUntrusted & self class isUntrusted not
ifTrue:
[SystemExceptions.MutationError
signal: 'Cannot move trusted class below untrusted superclass'].
needToRecompileMetaclasses := false.
aClass classPool isNil
ifTrue: [aClass setClassVariables: classVarDict]
ifFalse:
[classVarDict keysDo:
[:key |
(aClass classPool includesKey: key) ifFalse: [aClass addClassVarName: key]].
aClass classPool keys do:
[:aKey |
(classVarDict includesKey: aKey)
ifFalse:
[aClass removeClassVarName: aKey.
needToRecompileMetaclasses := true]]].
"If instance or indexed variables change, update
instance variables and instance spec of the class and all its subclasses"
(needToRecompileClasses := variableArray ~= aClass allInstVarNames
| needToRecompileMetaclasses) | (aClass shape ~~ realShape)
ifTrue:
[aClass instanceCount > 0 ifTrue: [ObjectMemory globalGarbageCollect].
aClass
updateInstanceVars: variableArray
superclass: newSuperclass
shape: realShape].
"Now add/remove pool dictionaries. FIXME: They may affect name binding,
so we should probably recompile everything if they change."
aClass sharedPoolDictionaries isEmpty
ifTrue: [aClass setSharedPools: sharedPoolNames]
ifFalse:
[sharedPoolNames do:
[:dict |
(aClass sharedPoolDictionaries includes: dict)
ifFalse: [aClass addSharedPool: dict]].
aClass sharedPoolDictionaries copy do:
[:dict |
(sharedPoolNames includes: dict)
ifFalse:
[aClass removeSharedPool: dict.
needToRecompileMetaclasses := true]]].
aClass superclass ~~ newSuperclass
ifTrue:
["Mutate the class if the set of class-instance variables changes."
self superclass allInstVarNames ~= newSuperclass class allInstVarNames
ifTrue:
[aClass class
updateInstanceVars:
newSuperclass class allInstVarNames,
aClass class instVarNames
superclass: newSuperclass class
shape: aClass class shape].
"Fix references between classes..."
aClass superclass removeSubclass: aClass.
newSuperclass addSubclass: aClass.
aClass superclass: newSuperclass.
needToRecompileClasses := true.
"...and between metaclasses..."
self superclass removeSubclass: self.
newSuperclass class addSubclass: self.
self superclass: newSuperclass class.
needToRecompileMetaclasses := true].
aClass category: categoryName.
"Please note that I need to recompile the classes in this sequence;
otherwise, the same error is propagated to each selector which is compiled
after an error is detected even though there are no further compilation
errors. Apparently, there is a bug in the primitive #primCompile:. This
can be cleaned up later"
needToRecompileClasses | needToRecompileMetaclasses
ifTrue:
[aClass compileAll.
needToRecompileMetaclasses ifTrue: [aClass class compileAll].
aClass compileAllSubclasses.
needToRecompileMetaclasses ifTrue: [aClass class compileAllSubclasses]].
Behavior flushCache.
^aClass
]
newMeta: className environment: aNamespace subclassOf: theSuperclass instanceVariableArray: arrayOfInstVarNames shape: shape classPool: classVarDict poolDictionaries: sharedPoolNames category: categoryName [
"Private - create a full featured class and install it"
<category: 'basic'>
| aClass |
aClass := self new.
classVarDict environment: aClass.
instanceClass := aClass.
aNamespace at: className put: aClass.
theSuperclass isNil ifFalse: [theSuperclass addSubclass: aClass].
Behavior flushCache.
^aClass
superclass: theSuperclass;
setName: className;
setEnvironment: aNamespace;
setInstanceVariables: arrayOfInstVarNames;
setInstanceSpec: shape instVars: arrayOfInstVarNames size;
setClassVariables: classVarDict;
setSharedPools: sharedPoolNames;
makeUntrusted: theSuperclass isUntrusted;
category: categoryName;
yourself
]
primaryInstance [
"Answer the only instance of the metaclass - present for compatibility"
<category: 'accessing'>
^instanceClass
]
soleInstance [
"Answer the only instance of the metaclass - present for compatibility"
<category: 'accessing'>
^instanceClass
]
instanceClass [
"Answer the only instance of the metaclass"
<category: 'accessing'>
^instanceClass
]
nameIn: aNamespace [
"Answer the class name when the class is referenced from aNamespace."
<category: 'printing'>
^self instanceClass nameIn: aNamespace
]
printOn: aStream in: aNamespace [
"Print on aStream the class name when the class is referenced from
aNamespace."
<category: 'printing'>
instanceClass printOn: aStream in: aNamespace.
aStream nextPutAll: ' class'
]
printOn: aStream [
"Print a represention of the receiver on aStream"
<category: 'printing'>
instanceClass printOn: aStream.
aStream nextPutAll: ' class'
]
storeOn: aStream [
"Store Smalltalk code compiling to the receiver on aStream"
<category: 'printing'>
instanceClass storeOn: aStream.
aStream nextPutAll: ' class'
]
initMetaclass: theSuperclass [
<category: 'private'>
instanceVariables := theSuperclass allInstVarNames.
instanceSpec := theSuperclass instanceSpec
]
parsePools: aString in: aNamespace [
<category: 'private'>
| tokens |
tokens := aString subStrings asArray.
^tokens collect:
[:poolName |
(poolName substrings: $.) inject: aNamespace
into:
[:namespace :key |
self validateIdentifier: key.
namespace at: key asGlobalKey
ifAbsent: [SystemExceptions.NotFound signalOn: poolName what: 'pool']]]
]
parse: aString toDictionary: dict [
<category: 'private'>
| tokenArray |
tokenArray := self parseVariableString: aString.
tokenArray do: [:element | dict at: element asSymbol put: nil].
^dict
]
growClassInstance [
<category: 'private'>
| newClass numInstVars |
newClass := self new.
numInstVars := self instSize.
1 to: numInstVars - 1
do: [:i | newClass instVarAt: i put: (instanceClass instVarAt: i)].
instanceClass become: newClass
]
asClass [
<category: 'testing functionality'>
^instanceClass
]
isMetaclass [
<category: 'testing functionality'>
^true
]
fileOutOn: aFileStream [
"File out complete class description: class definition, class and
instance methods"
<category: 'filing'>
instanceClass fileOutOn: aFileStream
]
]
|