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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
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
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package org.codehaus.groovy.transform;
import org.codehaus.groovy.ast.ASTNode;
import org.codehaus.groovy.ast.AnnotationNode;
import org.codehaus.groovy.ast.ClassCodeExpressionTransformer;
import org.codehaus.groovy.ast.ClassHelper;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.FieldNode;
import org.codehaus.groovy.ast.MethodNode;
import org.codehaus.groovy.ast.Parameter;
import org.codehaus.groovy.ast.PropertyNode;
import org.codehaus.groovy.ast.expr.ClassExpression;
import org.codehaus.groovy.ast.expr.ClosureExpression;
import org.codehaus.groovy.ast.expr.DeclarationExpression;
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.CatchStatement;
import org.codehaus.groovy.classgen.VariableScopeVisitor;
import org.codehaus.groovy.control.CompilePhase;
import org.codehaus.groovy.control.SourceUnit;
import org.codehaus.groovy.control.messages.SyntaxErrorMessage;
import org.codehaus.groovy.ast.stmt.BlockStatement;
import org.codehaus.groovy.ast.stmt.ExpressionStatement;
import org.codehaus.groovy.ast.stmt.ForStatement;
import org.codehaus.groovy.syntax.SyntaxException;
import org.objectweb.asm.Opcodes;
import groovy.lang.Reference;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
/**
* Handles generation of code for the @Category annotation.
*
* Transformation logic is as follows:
*
* - all non-static methods converted to static ones with an additional 'self' parameter
* - references to 'this' changed to the additional 'self' parameter
*
*
* @author Alex Tkachman
*/
@GroovyASTTransformation(phase = CompilePhase.CANONICALIZATION)
public class CategoryASTTransformation implements ASTTransformation, Opcodes {
// should not use a static variable because of possible changes to node metadata
// which would be visible to other compilation units
private final VariableExpression thisExpression = createThisExpression();
private static VariableExpression createThisExpression() {
VariableExpression expr = new VariableExpression("$this");
expr.setClosureSharedVariable(true);
return expr;
}
/**
* Property invocations done on 'this' reference are transformed so that the invocations at runtime are
* done on the additional parameter 'self'
*/
public void visit(ASTNode[] nodes, final SourceUnit source) {
if (nodes.length != 2 || !(nodes[0] instanceof AnnotationNode) || !(nodes[1] instanceof ClassNode)) {
source.getErrorCollector().addError(
new SyntaxErrorMessage(new SyntaxException("@Category can only be added to a ClassNode but got: " + (nodes.length==2?nodes[1]:"nothing"),
nodes[0].getLineNumber(), nodes[0].getColumnNumber()), source));
}
AnnotationNode annotation = (AnnotationNode) nodes[0];
ClassNode parent = (ClassNode) nodes[1];
ClassNode targetClass = getTargetClass(source, annotation);
thisExpression.setType(targetClass);
final LinkedList> varStack = new LinkedList>();
if (!ensureNoInstanceFieldOrProperty(source, parent)) return;
Set names = new HashSet();
for (FieldNode field : parent.getFields()) {
names.add(field.getName());
}
for (PropertyNode field : parent.getProperties()) {
names.add(field.getName());
}
varStack.add(names);
final Reference parameter = new Reference();
final ClassCodeExpressionTransformer expressionTransformer = new ClassCodeExpressionTransformer() {
protected SourceUnit getSourceUnit() {
return source;
}
private void addVariablesToStack(Parameter[] params) {
Set names = new HashSet();
names.addAll(varStack.getLast());
for (Parameter param : params) {
names.add(param.getName());
}
varStack.add(names);
}
@Override
public void visitCatchStatement(CatchStatement statement) {
varStack.getLast().add(statement.getVariable().getName());
super.visitCatchStatement(statement);
varStack.getLast().remove(statement.getVariable().getName());
}
@Override
public void visitMethod(MethodNode node) {
addVariablesToStack(node.getParameters());
super.visitMethod(node);
varStack.removeLast();
}
@Override
public void visitBlockStatement(BlockStatement block) {
Set names = new HashSet();
names.addAll(varStack.getLast());
varStack.add(names);
super.visitBlockStatement(block);
varStack.remove(names);
}
@Override
public void visitClosureExpression(ClosureExpression ce) {
addVariablesToStack(ce.getParameters());
super.visitClosureExpression(ce);
varStack.removeLast();
}
@Override
public void visitDeclarationExpression(DeclarationExpression expression) {
if (expression.isMultipleAssignmentDeclaration()) {
TupleExpression te = expression.getTupleExpression();
List list = te.getExpressions();
for (Expression arg : list) {
VariableExpression ve = (VariableExpression) arg;
varStack.getLast().add(ve.getName());
}
} else {
VariableExpression ve = expression.getVariableExpression();
varStack.getLast().add(ve.getName());
}
super.visitDeclarationExpression(expression);
}
@Override
public void visitForLoop(ForStatement forLoop) {
Expression exp = forLoop.getCollectionExpression();
exp.visit(this);
Parameter loopParam = forLoop.getVariable();
if (loopParam != null) {
varStack.getLast().add(loopParam.getName());
}
super.visitForLoop(forLoop);
}
@Override
public void visitExpressionStatement(ExpressionStatement es) {
// GROOVY-3543: visit the declaration expressions so that declaration variables get added on the varStack
Expression exp = es.getExpression();
if (exp instanceof DeclarationExpression) {
exp.visit(this);
}
super.visitExpressionStatement(es);
}
@Override
public Expression transform(Expression exp) {
if (exp instanceof VariableExpression) {
VariableExpression ve = (VariableExpression) exp;
if (ve.getName().equals("this"))
return thisExpression;
else {
if (!varStack.getLast().contains(ve.getName())) {
return new PropertyExpression(thisExpression, ve.getName());
}
}
} else if (exp instanceof PropertyExpression) {
PropertyExpression pe = (PropertyExpression) exp;
if (pe.getObjectExpression() instanceof VariableExpression) {
VariableExpression vex = (VariableExpression) pe.getObjectExpression();
if (vex.isThisExpression()) {
pe.setObjectExpression(thisExpression);
return pe;
}
}
} else if (exp instanceof ClosureExpression) {
ClosureExpression ce = (ClosureExpression) exp;
ce.getVariableScope().putReferencedLocalVariable((Parameter) parameter.get());
Parameter[] params = ce.getParameters();
if (params == null) {
params = Parameter.EMPTY_ARRAY;
} else if (params.length == 0) {
params = new Parameter[]{
new Parameter(ClassHelper.OBJECT_TYPE, "it")
};
}
addVariablesToStack(params);
ce.getCode().visit(this);
varStack.removeLast();
}
return super.transform(exp);
}
};
for (MethodNode method : parent.getMethods()) {
if (!method.isStatic()) {
method.setModifiers(method.getModifiers() | Opcodes.ACC_STATIC);
final Parameter[] origParams = method.getParameters();
final Parameter[] newParams = new Parameter[origParams.length + 1];
Parameter p = new Parameter(targetClass, "$this");
p.setClosureSharedVariable(true);
newParams[0] = p;
parameter.set(p);
System.arraycopy(origParams, 0, newParams, 1, origParams.length);
method.setParameters(newParams);
expressionTransformer.visitMethod(method);
}
}
new VariableScopeVisitor(source, true).visitClass(parent);
}
private boolean ensureNoInstanceFieldOrProperty(final SourceUnit source, final ClassNode parent) {
boolean valid = true;
for (FieldNode fieldNode : parent.getFields()) {
if (!fieldNode.isStatic() && fieldNode.getLineNumber()>0) {
// if <0, probably an AST transform or internal code (like generated metaclass field, ...)
addUnsupportedError(fieldNode, source);
valid = false;
}
}
for (PropertyNode propertyNode : parent.getProperties()) {
if (!propertyNode.isStatic() && propertyNode.getLineNumber()>0) {
// if <0, probably an AST transform or internal code (like generated metaclass field, ...)
addUnsupportedError(propertyNode, source);
valid = false;
}
}
return valid;
}
private static void addUnsupportedError(ASTNode node, SourceUnit unit) {
unit.getErrorCollector().addErrorAndContinue(
new SyntaxErrorMessage(
new SyntaxException("The @Category transformation does not support instance "+
(node instanceof FieldNode?"fields":"properties")
+ " but found ["+getName(node)+"]",
node.getLineNumber(),
node.getColumnNumber()
), unit
));
}
private static String getName(ASTNode node) {
if (node instanceof FieldNode) return ((FieldNode) node).getName();
if (node instanceof PropertyNode) return ((PropertyNode) node).getName();
return node.getText();
}
private ClassNode getTargetClass(SourceUnit source, AnnotationNode annotation) {
Expression value = annotation.getMember("value");
if (value == null || !(value instanceof ClassExpression)) {
//noinspection ThrowableInstanceNeverThrown
source.getErrorCollector().addErrorAndContinue(new SyntaxErrorMessage(
new SyntaxException("@groovy.lang.Category must define 'value' which is the class to apply this category to",
annotation.getLineNumber(), annotation.getColumnNumber(), annotation.getLastLineNumber(), annotation.getLastColumnNumber()),
source));
return null;
} else {
ClassExpression ce = (ClassExpression) value;
return ce.getType();
}
}
}