/*
* Copyright 2008-2014 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.GroovyBugError;
import org.codehaus.groovy.ast.ASTNode;
import org.codehaus.groovy.ast.AnnotatedNode;
import org.codehaus.groovy.ast.AnnotationNode;
import org.codehaus.groovy.ast.ClassNode;
import org.codehaus.groovy.ast.FieldNode;
import org.codehaus.groovy.ast.MethodNode;
import org.codehaus.groovy.ast.expr.Expression;
import org.codehaus.groovy.ast.stmt.Statement;
import org.codehaus.groovy.ast.stmt.TryCatchStatement;
import org.codehaus.groovy.control.CompilePhase;
import org.codehaus.groovy.control.SourceUnit;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import static org.codehaus.groovy.ast.ClassHelper.make;
import static org.codehaus.groovy.ast.tools.GeneralUtils.block;
import static org.codehaus.groovy.ast.tools.GeneralUtils.callX;
import static org.codehaus.groovy.ast.tools.GeneralUtils.ctorX;
import static org.codehaus.groovy.ast.tools.GeneralUtils.stmt;
import static org.codehaus.groovy.ast.tools.GeneralUtils.varX;
/**
* 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 {@code @}WithReadLock will obtain a read lock and release it in a finally block.<br>
* Any method annotated with {@code @}WithWriteLock will obtain a write lock and release it in a finally block.<br>
* For more information see {@link WithReadLock} and {@link WithWriteLock}
*
* @author Hamlet D'Arcy
*/
@GroovyASTTransformation(phase = CompilePhase.CANONICALIZATION)
public class ReadWriteLockASTTransformation extends AbstractASTTransformation {
private static final ClassNode READ_LOCK_TYPE = make(WithReadLock.class);
private static final ClassNode WRITE_LOCK_TYPE = make(WithWriteLock.class);
private static final ClassNode LOCK_TYPE = make(ReentrantReadWriteLock.class);
public static final String DEFAULT_STATIC_LOCKNAME = "$REENTRANTLOCK";
public static final String DEFAULT_INSTANCE_LOCKNAME = "$reentrantlock";
public void visit(ASTNode[] nodes, SourceUnit source) {
init(nodes, source);
AnnotatedNode parent = (AnnotatedNode) nodes[1];
AnnotationNode node = (AnnotationNode) nodes[0];
final boolean isWriteLock;
if (READ_LOCK_TYPE.equals(node.getClassNode())) {
isWriteLock = false;
} else if (WRITE_LOCK_TYPE.equals(node.getClassNode())) {
isWriteLock = true;
} else {
throw new GroovyBugError("Internal error: expecting [" + READ_LOCK_TYPE.getName() + ", " + WRITE_LOCK_TYPE.getName() + "]" + " but got: " + node.getClassNode().getName());
}
String myTypeName = "@" + node.getClassNode().getNameWithoutPackage();
String value = getMemberStringValue(node, "value");
if (parent instanceof MethodNode) {
MethodNode mNode = (MethodNode) parent;
ClassNode cNode = mNode.getDeclaringClass();
String lockExpr = determineLock(value, cNode, mNode.isStatic(), myTypeName);
if (lockExpr == null) return;
// get lock type
final Expression lockType;
if (isWriteLock) {
lockType = callX(varX(lockExpr, LOCK_TYPE), "writeLock");
} else {
lockType = callX(varX(lockExpr, LOCK_TYPE), "readLock");
}
Expression acquireLock = callX(lockType, "lock");
Expression releaseLock = callX(lockType, "unlock");
Statement originalCode = mNode.getCode();
mNode.setCode(block(
stmt(acquireLock),
new TryCatchStatement(originalCode, stmt(releaseLock))));
}
}
private String determineLock(String value, ClassNode targetClass, boolean isStatic, String myTypeName) {
if (value != null && value.length() > 0 && !value.equalsIgnoreCase(DEFAULT_INSTANCE_LOCKNAME)) {
FieldNode existingLockField = targetClass.getDeclaredField(value);
if (existingLockField == null) {
addError("Error during " + myTypeName + " processing: lock field with name '" + value + "' not found in class " + targetClass.getName(), targetClass);
return null;
}
if (existingLockField.isStatic() != isStatic) {
addError("Error during " + myTypeName + " processing: lock field with name '" + value + "' should " + (isStatic ? "" : "not ") + "be static", existingLockField);
return null;
}
return value;
}
if (isStatic) {
FieldNode field = targetClass.getDeclaredField(DEFAULT_STATIC_LOCKNAME);
if (field == null) {
int visibility = ACC_PRIVATE | ACC_STATIC | ACC_FINAL;
targetClass.addField(DEFAULT_STATIC_LOCKNAME, visibility, LOCK_TYPE, createLockObject());
} else if (!field.isStatic()) {
addError("Error during " + myTypeName + " processing: " + DEFAULT_STATIC_LOCKNAME + " field must be static", field);
return null;
}
return DEFAULT_STATIC_LOCKNAME;
}
FieldNode field = targetClass.getDeclaredField(DEFAULT_INSTANCE_LOCKNAME);
if (field == null) {
int visibility = ACC_PRIVATE | ACC_FINAL;
targetClass.addField(DEFAULT_INSTANCE_LOCKNAME, visibility, LOCK_TYPE, createLockObject());
} else if (field.isStatic()) {
addError("Error during " + myTypeName + " processing: " + DEFAULT_INSTANCE_LOCKNAME + " field must not be static", field);
return null;
}
return DEFAULT_INSTANCE_LOCKNAME;
}
private Expression createLockObject() {
return ctorX(LOCK_TYPE);
}
}