/*
* Copyright 2008-2010 the original author or authors.
*
* Licensed 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.transform;
import org.codehaus.groovy.control.CompilePhase;
import org.codehaus.groovy.control.SourceUnit;
import org.codehaus.groovy.control.messages.SyntaxErrorMessage;
import org.codehaus.groovy.ast.expr.*;
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.ast.*;
import org.codehaus.groovy.syntax.SyntaxException;
import org.objectweb.asm.Opcodes;
import groovy.lang.Reference;
import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
/**
* Handles generation of code for the @Category annotation.
* <p>
* Transformation logic is as follows:
* <ul>
* <li>all non-static methods converted to static ones with an additional 'self' parameter
* <li>references to 'this' changed to the additional 'self' parameter
* </ul>
*
* @author Alex Tkachman
*/
@GroovyASTTransformation(phase = CompilePhase.CANONICALIZATION)
public class CategoryASTTransformation implements ASTTransformation, Opcodes {
private static final VariableExpression THIS_EXPRESSION;
static {
THIS_EXPRESSION = new VariableExpression("$this");
THIS_EXPRESSION.setClosureSharedVariable(true);
}
/**
* 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)) {
throw new RuntimeException("Internal error: expecting [AnnotationNode, ClassNode] but got: " + Arrays.asList(nodes));
}
AnnotationNode annotation = (AnnotationNode) nodes[0];
ClassNode parent = (ClassNode) nodes[1];
ClassNode targetClass = getTargetClass(source, annotation);
final LinkedList<Set<String>> varStack = new LinkedList<Set<String>>();
Set<String> names = new HashSet<String>();
for (FieldNode field : parent.getFields()) {
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<String> names = new HashSet<String>();
names.addAll(varStack.getLast());
for (Parameter param : params) {
names.add(param.getName());
}
varStack.add(names);
}
@Override
public void visitMethod(MethodNode node) {
addVariablesToStack(node.getParameters());
super.visitMethod(node);
varStack.removeLast();
}
@Override
public void visitBlockStatement(BlockStatement block) {
Set<String> names = new HashSet<String>();
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<Expression> 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 THIS_EXPRESSION;
else {
if (!varStack.getLast().contains(ve.getName())) {
return new PropertyExpression(THIS_EXPRESSION, 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(THIS_EXPRESSION);
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 = new Parameter[0];
} 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);
}
}
}
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()),
source));
return null;
} else {
ClassExpression ce = (ClassExpression) value;
return ce.getType();
}
}
}