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Groovy: A powerful, dynamic language for the JVM
/*
* Licensed to the Apache Software Foundation (ASF) under one
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* 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
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* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
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* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.codehaus.groovy.transform;
import groovy.lang.Lazy;
import groovy.transform.Field;
import org.codehaus.groovy.GroovyBugError;
import org.codehaus.groovy.ast.ASTNode;
import org.codehaus.groovy.ast.AnnotatedNode;
import org.codehaus.groovy.ast.AnnotationNode;
import org.codehaus.groovy.ast.ClassCodeExpressionTransformer;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.FieldNode;
import org.codehaus.groovy.ast.MethodNode;
import org.codehaus.groovy.ast.Variable;
import org.codehaus.groovy.ast.VariableScope;
import org.codehaus.groovy.ast.expr.BinaryExpression;
import org.codehaus.groovy.ast.expr.ClosureExpression;
import org.codehaus.groovy.ast.expr.ConstantExpression;
import org.codehaus.groovy.ast.expr.DeclarationExpression;
import org.codehaus.groovy.ast.expr.Expression;
import org.codehaus.groovy.ast.expr.VariableExpression;
import org.codehaus.groovy.ast.stmt.ExpressionStatement;
import org.codehaus.groovy.classgen.VariableScopeVisitor;
import org.codehaus.groovy.control.CompilePhase;
import org.codehaus.groovy.control.SourceUnit;
import org.objectweb.asm.Opcodes;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import static org.codehaus.groovy.ast.ClassHelper.make;
/**
* Handles transformation for the @Field annotation.
*
* @author Paul King
* @author Cedric Champeau
*/
@GroovyASTTransformation(phase = CompilePhase.SEMANTIC_ANALYSIS)
public class FieldASTTransformation extends ClassCodeExpressionTransformer implements ASTTransformation, Opcodes {
private static final Class MY_CLASS = Field.class;
private static final ClassNode MY_TYPE = make(MY_CLASS);
private static final ClassNode LAZY_TYPE = make(Lazy.class);
private static final String MY_TYPE_NAME = "@" + MY_TYPE.getNameWithoutPackage();
private static final ClassNode ASTTRANSFORMCLASS_TYPE = make(GroovyASTTransformationClass.class);
private SourceUnit sourceUnit;
private DeclarationExpression candidate;
private boolean insideScriptBody;
private String variableName;
private FieldNode fieldNode;
private ClosureExpression currentClosure;
public void visit(ASTNode[] nodes, SourceUnit source) {
sourceUnit = source;
if (nodes.length != 2 || !(nodes[0] instanceof AnnotationNode) || !(nodes[1] instanceof AnnotatedNode)) {
throw new GroovyBugError("Internal error: expecting [AnnotationNode, AnnotatedNode] but got: " + Arrays.asList(nodes));
}
AnnotatedNode parent = (AnnotatedNode) nodes[1];
AnnotationNode node = (AnnotationNode) nodes[0];
if (!MY_TYPE.equals(node.getClassNode())) return;
if (parent instanceof DeclarationExpression) {
DeclarationExpression de = (DeclarationExpression) parent;
ClassNode cNode = de.getDeclaringClass();
if (!cNode.isScript()) {
addError("Annotation " + MY_TYPE_NAME + " can only be used within a Script.", parent);
return;
}
candidate = de;
// GROOVY-4548: temp fix to stop CCE until proper support is added
if (de.isMultipleAssignmentDeclaration()) {
addError("Annotation " + MY_TYPE_NAME + " not supported with multiple assignment notation.", parent);
return;
}
VariableExpression ve = de.getVariableExpression();
variableName = ve.getName();
// set owner null here, it will be updated by addField
fieldNode = new FieldNode(variableName, ve.getModifiers(), ve.getType(), null, de.getRightExpression());
fieldNode.setSourcePosition(de);
cNode.addField(fieldNode);
// GROOVY-4833 : annotations that are not Groovy transforms should be transferred to the generated field
// GROOVY-6112 : also copy acceptable Groovy transforms
final List annotations = de.getAnnotations();
for (AnnotationNode annotation : annotations) {
// GROOVY-6337 HACK: in case newly created field is @Lazy
if (annotation.getClassNode().equals(LAZY_TYPE)) {
LazyASTTransformation.visitField(annotation, fieldNode);
}
final ClassNode annotationClassNode = annotation.getClassNode();
if (notTransform(annotationClassNode) || acceptableTransform(annotation)) {
fieldNode.addAnnotation(annotation);
}
}
super.visitClass(cNode);
// GROOVY-5207 So that Closures can see newly added fields
// (not super efficient for a very large class with many @Fields but we chose simplicity
// and understandability of this solution over more complex but efficient alternatives)
VariableScopeVisitor scopeVisitor = new VariableScopeVisitor(source);
scopeVisitor.visitClass(cNode);
}
}
private boolean acceptableTransform(AnnotationNode annotation) {
// TODO also check for phase after sourceUnit.getPhase()? but will be ignored anyway?
// TODO we should only copy those annotations with FIELD_TARGET but haven't visited annotations
// and gathered target info at this phase, so we can't do this:
// return annotation.isTargetAllowed(AnnotationNode.FIELD_TARGET);
// instead just don't copy ourselves for now
return !annotation.getClassNode().equals(MY_TYPE);
}
private boolean notTransform(ClassNode annotationClassNode) {
return annotationClassNode.getAnnotations(ASTTRANSFORMCLASS_TYPE).isEmpty();
}
@Override
public Expression transform(Expression expr) {
if (expr == null) return null;
if (expr instanceof DeclarationExpression) {
DeclarationExpression de = (DeclarationExpression) expr;
if (de.getLeftExpression() == candidate.getLeftExpression()) {
if (insideScriptBody) {
// TODO make EmptyExpression work
// partially works but not if only thing in script
// return EmptyExpression.INSTANCE;
return new ConstantExpression(null);
}
addError("Annotation " + MY_TYPE_NAME + " can only be used within a Script body.", expr);
return expr;
}
} else if (insideScriptBody && expr instanceof VariableExpression && currentClosure != null) {
VariableExpression ve = (VariableExpression) expr;
if (ve.getName().equals(variableName)) {
// we may only check the variable name because the Groovy compiler
// already fails if a variable with the same name already exists in the scope.
// this means that a closure cannot shadow a class variable
ve.setAccessedVariable(fieldNode);
final VariableScope variableScope = currentClosure.getVariableScope();
final Iterator iterator = variableScope.getReferencedLocalVariablesIterator();
while (iterator.hasNext()) {
Variable next = iterator.next();
if (next.getName().equals(variableName)) iterator.remove();
}
variableScope.putReferencedClassVariable(fieldNode);
return ve;
}
}
return expr.transformExpression(this);
}
@Override
public void visitClosureExpression(final ClosureExpression expression) {
ClosureExpression old = currentClosure;
currentClosure = expression;
super.visitClosureExpression(expression);
currentClosure = old;
}
@Override
public void visitMethod(MethodNode node) {
Boolean oldInsideScriptBody = insideScriptBody;
if (node.isScriptBody()) insideScriptBody = true;
super.visitMethod(node);
insideScriptBody = oldInsideScriptBody;
}
@Override
public void visitExpressionStatement(ExpressionStatement es) {
Expression exp = es.getExpression();
if (exp instanceof BinaryExpression) {
exp.visit(this);
}
super.visitExpressionStatement(es);
}
protected SourceUnit getSourceUnit() {
return sourceUnit;
}
}