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Groovy: A powerful, dynamic language for the JVM
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* 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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* 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.Memoized;
import org.codehaus.groovy.ast.ASTNode;
import org.codehaus.groovy.ast.AnnotatedNode;
import org.codehaus.groovy.ast.AnnotationNode;
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.expr.ClosureExpression;
import org.codehaus.groovy.ast.expr.Expression;
import org.codehaus.groovy.ast.expr.MethodCallExpression;
import org.codehaus.groovy.ast.stmt.BlockStatement;
import org.codehaus.groovy.ast.stmt.Statement;
import org.codehaus.groovy.classgen.VariableScopeVisitor;
import org.codehaus.groovy.control.CompilePhase;
import org.codehaus.groovy.control.SourceUnit;
import java.util.ArrayList;
import java.util.List;
import static org.codehaus.groovy.ast.ClassHelper.make;
import static org.codehaus.groovy.ast.tools.GeneralUtils.args;
import static org.codehaus.groovy.ast.tools.GeneralUtils.callThisX;
import static org.codehaus.groovy.ast.tools.GeneralUtils.callX;
import static org.codehaus.groovy.ast.tools.GeneralUtils.cloneParams;
import static org.codehaus.groovy.ast.tools.GeneralUtils.constX;
import static org.codehaus.groovy.ast.tools.GeneralUtils.fieldX;
import static org.codehaus.groovy.ast.tools.GeneralUtils.returnS;
import static org.codehaus.groovy.ast.tools.GeneralUtils.stmt;
import static org.codehaus.groovy.ast.tools.GeneralUtils.varX;
import static org.codehaus.groovy.ast.tools.GenericsUtils.newClass;
/**
* Handles generation of code for the {@link Memoized} annotation.
*
* @author Andrey Bloschetsov
*/
@GroovyASTTransformation(phase = CompilePhase.SEMANTIC_ANALYSIS)
public class MemoizedASTTransformation extends AbstractASTTransformation {
private static final String CLOSURE_CALL_METHOD_NAME = "call";
private static final Class MY_CLASS = Memoized.class;
private static final ClassNode MY_TYPE = make(MY_CLASS);
private static final String MY_TYPE_NAME = "@" + MY_TYPE.getNameWithoutPackage();
private static final String PROTECTED_CACHE_SIZE_NAME = "protectedCacheSize";
private static final String MAX_CACHE_SIZE_NAME = "maxCacheSize";
private static final String CLOSURE_LABEL = "Closure";
private static final String METHOD_LABEL = "Priv";
public void visit(ASTNode[] nodes, final SourceUnit source) {
init(nodes, source);
AnnotationNode annotationNode = (AnnotationNode) nodes[0];
AnnotatedNode annotatedNode = (AnnotatedNode) nodes[1];
if (MY_TYPE.equals(annotationNode.getClassNode()) && annotatedNode instanceof MethodNode) {
MethodNode methodNode = (MethodNode) annotatedNode;
if (methodNode.isAbstract()) {
addError("Annotation " + MY_TYPE_NAME + " cannot be used for abstract methods.", methodNode);
return;
}
if (methodNode.isVoidMethod()) {
addError("Annotation " + MY_TYPE_NAME + " cannot be used for void methods.", methodNode);
return;
}
ClassNode ownerClassNode = methodNode.getDeclaringClass();
MethodNode delegatingMethod = buildDelegatingMethod(methodNode, ownerClassNode);
ownerClassNode.addMethod(delegatingMethod);
int modifiers = FieldNode.ACC_PRIVATE | FieldNode.ACC_FINAL;
if (methodNode.isStatic()) {
modifiers = modifiers | FieldNode.ACC_STATIC;
}
int protectedCacheSize = getMemberIntValue(annotationNode, PROTECTED_CACHE_SIZE_NAME);
int maxCacheSize = getMemberIntValue(annotationNode, MAX_CACHE_SIZE_NAME);
MethodCallExpression memoizeClosureCallExpression =
buildMemoizeClosureCallExpression(delegatingMethod, protectedCacheSize, maxCacheSize);
String memoizedClosureFieldName = buildUniqueName(ownerClassNode, CLOSURE_LABEL, methodNode);
FieldNode memoizedClosureField = new FieldNode(memoizedClosureFieldName, modifiers,
newClass(ClassHelper.CLOSURE_TYPE), null, memoizeClosureCallExpression);
ownerClassNode.addField(memoizedClosureField);
BlockStatement newCode = new BlockStatement();
MethodCallExpression closureCallExpression = callX(
fieldX(memoizedClosureField), CLOSURE_CALL_METHOD_NAME, args(methodNode.getParameters()));
closureCallExpression.setImplicitThis(false);
newCode.addStatement(returnS(closureCallExpression));
methodNode.setCode(newCode);
VariableScopeVisitor visitor = new VariableScopeVisitor(source);
visitor.visitClass(ownerClassNode);
}
}
private MethodNode buildDelegatingMethod(final MethodNode annotatedMethod, final ClassNode ownerClassNode) {
Statement code = annotatedMethod.getCode();
int access = ACC_PROTECTED;
if (annotatedMethod.isStatic()) {
access = ACC_PRIVATE | ACC_STATIC;
}
MethodNode method = new MethodNode(
buildUniqueName(ownerClassNode, METHOD_LABEL, annotatedMethod),
access,
annotatedMethod.getReturnType(),
cloneParams(annotatedMethod.getParameters()),
annotatedMethod.getExceptions(),
code
);
List sourceAnnotations = annotatedMethod.getAnnotations();
method.addAnnotations(new ArrayList(sourceAnnotations));
return method;
}
private static final String MEMOIZE_METHOD_NAME = "memoize";
private static final String MEMOIZE_AT_MOST_METHOD_NAME = "memoizeAtMost";
private static final String MEMOIZE_AT_LEAST_METHOD_NAME = "memoizeAtLeast";
private static final String MEMOIZE_BETWEEN_METHOD_NAME = "memoizeBetween";
private MethodCallExpression buildMemoizeClosureCallExpression(MethodNode privateMethod,
int protectedCacheSize, int maxCacheSize) {
Parameter[] srcParams = privateMethod.getParameters();
Parameter[] newParams = cloneParams(srcParams);
List argList = new ArrayList(newParams.length);
for (int i = 0; i < srcParams.length; i++) {
argList.add(varX(newParams[i]));
}
ClosureExpression expression = new ClosureExpression(
newParams,
stmt(callThisX(privateMethod.getName(), args(argList)))
);
MethodCallExpression mce;
if (protectedCacheSize == 0 && maxCacheSize == 0) {
mce = callX(expression, MEMOIZE_METHOD_NAME);
} else if (protectedCacheSize == 0) {
mce = callX(expression, MEMOIZE_AT_MOST_METHOD_NAME, args(constX(maxCacheSize)));
} else if (maxCacheSize == 0) {
mce = callX(expression, MEMOIZE_AT_LEAST_METHOD_NAME, args(constX(protectedCacheSize)));
} else {
mce = callX(expression, MEMOIZE_BETWEEN_METHOD_NAME, args(constX(protectedCacheSize), constX(maxCacheSize)));
}
mce.setImplicitThis(false);
return mce;
}
private static String buildUniqueName(ClassNode owner, String ident, MethodNode methodNode) {
StringBuilder nameBuilder = new StringBuilder("memoizedMethod" + ident + "$").append(methodNode.getName());
if (methodNode.getParameters() != null) {
for (Parameter parameter : methodNode.getParameters()) {
nameBuilder.append(buildTypeName(parameter.getType()));
}
}
while (owner.getField(nameBuilder.toString()) != null) {
nameBuilder.insert(0, "_");
}
return nameBuilder.toString();
}
private static String buildTypeName(ClassNode type) {
if (type.isArray()) {
return String.format("%sArray", buildTypeName(type.getComponentType()));
}
return type.getNameWithoutPackage();
}
}