/*
* 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 groovy.transform.WithReadLock;
import groovy.transform.WithWriteLock;
import org.codehaus.groovy.ast.*;
import org.codehaus.groovy.ast.expr.*;
import org.codehaus.groovy.ast.stmt.*;
import org.codehaus.groovy.control.CompilePhase;
import org.codehaus.groovy.control.SourceUnit;
import org.codehaus.groovy.syntax.Token;
import org.objectweb.asm.Opcodes;
import java.util.Arrays;
import java.util.concurrent.locks.ReentrantReadWriteLock;
/**
* Handles generation of code for the {@code @}WithReadLock and {@code @}WithWriteLock annotation. <br/>
* This transformation adds an instance of ReentrantReadWriteLock to the class. <br/>
* Any method annotated with @WithReadLock will obtain a read lock and release it in a finally block.<br/>
* Any method annotated with @WithWriteLock will obtain a write lock and release it in a finally block.<br/>
* For more information see {@link WithReadLock} and {@link WithWriteLock}<br/>
* @author Hamlet D'Arcy
*/
@GroovyASTTransformation(phase = CompilePhase.CANONICALIZATION)
public class ReadWriteLockASTTransformation implements ASTTransformation, Opcodes {
private static final ClassNode READ_LOCK_TYPE = new ClassNode(WithReadLock.class);
private static final ClassNode WRITE_LOCK_TYPE = new ClassNode(WithWriteLock.class);
private static final ClassNode LOCK_TYPE = new ClassNode(ReentrantReadWriteLock.class);
private static final Token ASSIGN = Token.newSymbol("=", -1, -1);
public void visit(ASTNode[] nodes, SourceUnit source) {
if (nodes.length != 2 || !(nodes[0] instanceof AnnotationNode) || !(nodes[1] instanceof AnnotatedNode)) {
throw new RuntimeException("Internal error: expecting [AnnotationNode, AnnotatedNode] but got: " + Arrays.asList(nodes));
}
AnnotatedNode parent = (AnnotatedNode) nodes[1];
AnnotationNode node = (AnnotationNode) nodes[0];
if (!READ_LOCK_TYPE.equals(node.getClassNode()) && !WRITE_LOCK_TYPE.equals(node.getClassNode())) return;
boolean isWriteLock = false;
if (READ_LOCK_TYPE.equals(node.getClassNode())) {
isWriteLock = true;
}
String myTypeName = "@" + node.getClassNode().getNameWithoutPackage();
Expression valueExpr = node.getMember("value");
String value = null;
if (valueExpr instanceof ConstantExpression) {
ConstantExpression ce = (ConstantExpression) valueExpr;
Object valueObject = ce.getValue();
if (valueObject != null) value = valueObject.toString();
}
if (parent instanceof MethodNode) {
MethodNode mNode = (MethodNode) parent;
ClassNode cNode = mNode.getDeclaringClass();
String lockExpr = determineLock(value, cNode, mNode.isStatic(), myTypeName);
// get lock type
final Expression lockType;
if (isWriteLock) {
lockType = new MethodCallExpression(new VariableExpression(lockExpr), "writeLock", ArgumentListExpression.EMPTY_ARGUMENTS);
} else {
lockType = new MethodCallExpression(new VariableExpression(lockExpr), "readLock", ArgumentListExpression.EMPTY_ARGUMENTS);
}
MethodCallExpression acquireLock = new MethodCallExpression(lockType, "lock", ArgumentListExpression.EMPTY_ARGUMENTS);
MethodCallExpression releaseLock = new MethodCallExpression(lockType, "unlock", ArgumentListExpression.EMPTY_ARGUMENTS);
Statement originalCode = mNode.getCode();
BlockStatement body = new BlockStatement();
body.addStatement(new ExpressionStatement(acquireLock));
body.addStatement(new TryCatchStatement(originalCode, new ExpressionStatement(releaseLock)));
mNode.setCode(body);
}
}
private String determineLock(String value, ClassNode targetClass, boolean isStatic, String myTypeName) {
if (value != null && value.length() > 0 && !value.equalsIgnoreCase("$reentrantlock")) {
if (targetClass.getDeclaredField(value) == null) {
throw new RuntimeException("Error during " + myTypeName + " processing: lock field with name '" + value + "' not found in class " + targetClass.getName());
}
if (targetClass.getDeclaredField(value).isStatic() != isStatic) {
throw new RuntimeException("Error during " + myTypeName + " processing: lock field with name '" + value + "' should " + (isStatic ? "" : "not ") + "be static");
}
return value;
}
if (isStatic) {
FieldNode field = targetClass.getDeclaredField("$REENTRANTLOCK");
if (field == null) {
int visibility = ACC_PRIVATE | ACC_STATIC | ACC_FINAL;
targetClass.addField("$REENTRANTLOCK", visibility, LOCK_TYPE, createLockObject());
} else if (!field.isStatic()) {
throw new RuntimeException("Error during " + myTypeName + " processing: $REENTRANTLOCK field must be static");
}
return "$REENTRANTLOCK";
}
FieldNode field = targetClass.getDeclaredField("$reentrantlock");
if (field == null) {
int visibility = ACC_PRIVATE | ACC_FINAL;
targetClass.addField("$reentrantlock", visibility, LOCK_TYPE, createLockObject());
} else if (field.isStatic()) {
throw new RuntimeException("Error during " + myTypeName + " processing: $reentrantlock field must not be static");
}
return "$reentrantlock";
}
private Expression createLockObject() {
return new ConstructorCallExpression(LOCK_TYPE, MethodCallExpression.NO_ARGUMENTS);
}
}