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Groovy: A powerful, dynamic language for the JVM
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.codehaus.groovy.classgen;
import org.codehaus.groovy.ast.ClassHelper;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.FieldNode;
import org.codehaus.groovy.ast.InnerClassNode;
import org.codehaus.groovy.ast.MethodNode;
import org.codehaus.groovy.ast.Parameter;
import org.codehaus.groovy.ast.PropertyNode;
import org.codehaus.groovy.ast.VariableScope;
import org.codehaus.groovy.ast.expr.ClosureExpression;
import org.codehaus.groovy.ast.expr.ConstructorCallExpression;
import org.codehaus.groovy.ast.expr.Expression;
import org.codehaus.groovy.ast.expr.PropertyExpression;
import org.codehaus.groovy.ast.expr.TupleExpression;
import org.codehaus.groovy.ast.expr.VariableExpression;
import org.codehaus.groovy.ast.stmt.BlockStatement;
import org.codehaus.groovy.ast.stmt.ExpressionStatement;
import org.codehaus.groovy.control.CompilationUnit;
import org.codehaus.groovy.control.SourceUnit;
import org.objectweb.asm.Opcodes;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
public class InnerClassVisitor extends InnerClassVisitorHelper implements Opcodes {
private final SourceUnit sourceUnit;
private ClassNode classNode;
private static final int PUBLIC_SYNTHETIC = Opcodes.ACC_PUBLIC + Opcodes.ACC_SYNTHETIC;
private FieldNode thisField = null;
private MethodNode currentMethod;
private FieldNode currentField;
private boolean processingObjInitStatements = false;
private boolean inClosure = false;
public InnerClassVisitor(CompilationUnit cu, SourceUnit su) {
sourceUnit = su;
}
@Override
protected SourceUnit getSourceUnit() {
return sourceUnit;
}
@Override
public void visitClass(ClassNode node) {
this.classNode = node;
thisField = null;
InnerClassNode innerClass = null;
if (!node.isEnum() && !node.isInterface() && node instanceof InnerClassNode) {
innerClass = (InnerClassNode) node;
if (!isStatic(innerClass) && innerClass.getVariableScope() == null) {
thisField = innerClass.addField("this$0", PUBLIC_SYNTHETIC, node.getOuterClass().getPlainNodeReference(), null);
}
}
super.visitClass(node);
if (node.isEnum() || node.isInterface()) return;
if (innerClass == null) return;
if (node.getSuperClass().isInterface()) {
node.addInterface(node.getUnresolvedSuperClass());
node.setUnresolvedSuperClass(ClassHelper.OBJECT_TYPE);
}
}
@Override
public void visitClosureExpression(ClosureExpression expression) {
boolean inClosureOld = inClosure;
inClosure = true;
super.visitClosureExpression(expression);
inClosure = inClosureOld;
}
@Override
protected void visitObjectInitializerStatements(ClassNode node) {
processingObjInitStatements = true;
super.visitObjectInitializerStatements(node);
processingObjInitStatements = false;
}
private static boolean shouldHandleImplicitThisForInnerClass(ClassNode cn) {
if (cn.isEnum() || cn.isInterface()) return false;
if ((cn.getModifiers() & Opcodes.ACC_STATIC) != 0) return false;
if (!(cn instanceof InnerClassNode)) return false;
InnerClassNode innerClass = (InnerClassNode) cn;
// scope != null means aic, we don't handle that here
if (innerClass.getVariableScope() != null) return false;
// static inner classes don't need this$0
return (innerClass.getModifiers() & ACC_STATIC) == 0;
}
@Override
protected void visitConstructorOrMethod(MethodNode node, boolean isConstructor) {
this.currentMethod = node;
visitAnnotations(node);
visitClassCodeContainer(node.getCode());
// GROOVY-5681: initial expressions should be visited too!
for (Parameter param : node.getParameters()) {
if (param.hasInitialExpression()) {
param.getInitialExpression().visit(this);
}
visitAnnotations(param);
}
this.currentMethod = null;
}
@Override
public void visitField(FieldNode node) {
this.currentField = node;
super.visitField(node);
this.currentField = null;
}
@Override
public void visitProperty(PropertyNode node) {
final FieldNode field = node.getField();
final Expression init = field.getInitialExpression();
field.setInitialValueExpression(null);
super.visitProperty(node);
field.setInitialValueExpression(init);
}
@Override
public void visitConstructorCallExpression(ConstructorCallExpression call) {
super.visitConstructorCallExpression(call);
if (!call.isUsingAnonymousInnerClass()) {
passThisReference(call);
return;
}
InnerClassNode innerClass = (InnerClassNode) call.getType();
ClassNode outerClass = innerClass.getOuterClass();
ClassNode superClass = innerClass.getSuperClass();
if (superClass instanceof InnerClassNode
&& !superClass.isInterface()
&& !(superClass.isStaticClass()||((superClass.getModifiers()&ACC_STATIC)==ACC_STATIC))) {
insertThis0ToSuperCall(call, innerClass);
}
if (!innerClass.getDeclaredConstructors().isEmpty()) return;
if ((innerClass.getModifiers() & ACC_STATIC) != 0) return;
VariableScope scope = innerClass.getVariableScope();
if (scope == null) return;
// expressions = constructor call arguments
List expressions = ((TupleExpression) call.getArguments()).getExpressions();
// block = init code for the constructor we produce
BlockStatement block = new BlockStatement();
// parameters = parameters of the constructor
final int additionalParamCount = 1 + scope.getReferencedLocalVariablesCount();
List parameters = new ArrayList(expressions.size() + additionalParamCount);
// superCallArguments = arguments for the super call == the constructor call arguments
List superCallArguments = new ArrayList(expressions.size());
// first we add a super() call for all expressions given in the
// constructor call expression
int pCount = additionalParamCount;
for (Expression expr : expressions) {
pCount++;
// add one parameter for each expression in the
// constructor call
Parameter param = new Parameter(ClassHelper.OBJECT_TYPE, "p" + pCount);
parameters.add(param);
// add to super call
superCallArguments.add(new VariableExpression(param));
}
// add the super call
ConstructorCallExpression cce = new ConstructorCallExpression(
ClassNode.SUPER,
new TupleExpression(superCallArguments)
);
block.addStatement(new ExpressionStatement(cce));
// we need to add "this" to access unknown methods/properties
// this is saved in a field named this$0
pCount = 0;
expressions.add(pCount, VariableExpression.THIS_EXPRESSION);
boolean isStatic = isStaticThis(innerClass,scope);
ClassNode outerClassType = getClassNode(outerClass, isStatic);
if (!isStatic && inClosure) outerClassType = ClassHelper.CLOSURE_TYPE;
outerClassType = outerClassType.getPlainNodeReference();
Parameter thisParameter = new Parameter(outerClassType, "p" + pCount);
parameters.add(pCount, thisParameter);
thisField = innerClass.addField("this$0", PUBLIC_SYNTHETIC, outerClassType, null);
addFieldInit(thisParameter, thisField, block);
// for each shared variable we add a reference and save it as field
for (Iterator it = scope.getReferencedLocalVariablesIterator(); it.hasNext();) {
pCount++;
org.codehaus.groovy.ast.Variable var = (org.codehaus.groovy.ast.Variable) it.next();
VariableExpression ve = new VariableExpression(var);
ve.setClosureSharedVariable(true);
ve.setUseReferenceDirectly(true);
expressions.add(pCount, ve);
ClassNode rawReferenceType = ClassHelper.REFERENCE_TYPE.getPlainNodeReference();
Parameter p = new Parameter(rawReferenceType, "p" + pCount);
parameters.add(pCount, p);
p.setOriginType(var.getOriginType());
final VariableExpression initial = new VariableExpression(p);
initial.setSynthetic(true);
initial.setUseReferenceDirectly(true);
final FieldNode pField = innerClass.addFieldFirst(ve.getName(), PUBLIC_SYNTHETIC,rawReferenceType, initial);
pField.setHolder(true);
pField.setOriginType(ClassHelper.getWrapper(var.getOriginType()));
}
innerClass.addConstructor(ACC_SYNTHETIC, parameters.toArray(new Parameter[0]), ClassNode.EMPTY_ARRAY, block);
}
private boolean isStaticThis(InnerClassNode innerClass, VariableScope scope) {
if (inClosure) return false;
boolean ret = innerClass.isStaticClass();
if ( innerClass.getEnclosingMethod()!=null) {
ret = ret || innerClass.getEnclosingMethod().isStatic();
} else if (currentField!=null) {
ret = ret || currentField.isStatic();
} else if (currentMethod!=null && "".equals(currentMethod.getName())) {
ret = true;
}
return ret;
}
// this is the counterpart of addThisReference(). To non-static inner classes, outer this should be
// passed as the first argument implicitly.
private void passThisReference(ConstructorCallExpression call) {
ClassNode cn = call.getType().redirect();
if (!shouldHandleImplicitThisForInnerClass(cn)) return;
boolean isInStaticContext = true;
if (currentMethod != null)
isInStaticContext = currentMethod.getVariableScope().isInStaticContext();
else if (currentField != null)
isInStaticContext = currentField.isStatic();
else if (processingObjInitStatements)
isInStaticContext = false;
// if constructor call is not in static context, return
if (isInStaticContext) {
// constructor call is in static context and the inner class is non-static - 1st arg is supposed to be
// passed as enclosing "this" instance
//
Expression args = call.getArguments();
if (args instanceof TupleExpression && ((TupleExpression) args).getExpressions().isEmpty()) {
addError("No enclosing instance passed in constructor call of a non-static inner class", call);
}
return;
}
insertThis0ToSuperCall(call, cn);
}
private void insertThis0ToSuperCall(final ConstructorCallExpression call, final ClassNode cn) {
// calculate outer class which we need for this$0
ClassNode parent = classNode;
int level = 0;
for (; parent != null && parent != cn.getOuterClass(); parent = parent.getOuterClass()) {
level++;
}
// if constructor call is not in outer class, don't pass 'this' implicitly. Return.
if (parent == null) return;
//add this parameter to node
Expression argsExp = call.getArguments();
if (argsExp instanceof TupleExpression) {
TupleExpression argsListExp = (TupleExpression) argsExp;
Expression this0 = VariableExpression.THIS_EXPRESSION;
for (int i = 0; i != level; ++i)
this0 = new PropertyExpression(this0, "this$0");
argsListExp.getExpressions().add(0, this0);
}
}
}