/*
* Copyright 2011 Google Inc. All Rights Reserved.
*
* 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 com.google.devtools.j2objc.translate;
import com.google.common.collect.Lists;
import com.google.devtools.j2objc.ast.AbstractTypeDeclaration;
import com.google.devtools.j2objc.ast.AnnotationTypeDeclaration;
import com.google.devtools.j2objc.ast.Block;
import com.google.devtools.j2objc.ast.CompilationUnit;
import com.google.devtools.j2objc.ast.Expression;
import com.google.devtools.j2objc.ast.ExpressionStatement;
import com.google.devtools.j2objc.ast.FunctionInvocation;
import com.google.devtools.j2objc.ast.MethodDeclaration;
import com.google.devtools.j2objc.ast.NativeStatement;
import com.google.devtools.j2objc.ast.PrefixExpression;
import com.google.devtools.j2objc.ast.SimpleName;
import com.google.devtools.j2objc.ast.Statement;
import com.google.devtools.j2objc.ast.SuperMethodInvocation;
import com.google.devtools.j2objc.ast.ThisExpression;
import com.google.devtools.j2objc.ast.TreeUtil;
import com.google.devtools.j2objc.ast.TypeDeclaration;
import com.google.devtools.j2objc.ast.UnitTreeVisitor;
import com.google.devtools.j2objc.ast.VariableDeclarationFragment;
import com.google.devtools.j2objc.types.ExecutablePair;
import com.google.devtools.j2objc.types.FunctionElement;
import com.google.devtools.j2objc.types.GeneratedExecutableElement;
import com.google.devtools.j2objc.types.PointerType;
import com.google.devtools.j2objc.util.ElementUtil;
import com.google.devtools.j2objc.util.NameTable;
import com.google.devtools.j2objc.util.TypeUtil;
import java.util.List;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.element.Modifier;
import javax.lang.model.element.TypeElement;
import javax.lang.model.element.VariableElement;
import javax.lang.model.type.TypeMirror;
/**
* Adds release methods to Java classes, in preparation for translation
* to iOS. Because Objective-C allows messages to be sent to nil, all
* fields can be released regardless of whether they currently reference
* data.
*
* @author Tom Ball
*/
public class DestructorGenerator extends UnitTreeVisitor {
private final ExecutableElement superDeallocElement =
GeneratedExecutableElement.newMethodWithSelector(
NameTable.DEALLOC_METHOD, typeUtil.getVoid(), TypeUtil.NS_OBJECT)
.addModifiers(Modifier.PUBLIC);
public DestructorGenerator(CompilationUnit unit) {
super(unit);
}
@Override
public void endVisit(AnnotationTypeDeclaration node) {
addDeallocMethod(node);
}
@Override
public void endVisit(TypeDeclaration node) {
if (!node.isInterface()) {
addDeallocMethod(node);
}
}
private void addDeallocMethod(AbstractTypeDeclaration node) {
TypeElement type = node.getTypeElement();
boolean hasFinalize = hasFinalizeMethod(type);
List<Statement> releaseStatements = createReleaseStatements(node);
if (releaseStatements.isEmpty() && !hasFinalize) {
return;
}
ExecutableElement deallocElement = GeneratedExecutableElement.newMethodWithSelector(
NameTable.DEALLOC_METHOD, typeUtil.getVoid(), type)
.addModifiers(Modifier.PUBLIC);
MethodDeclaration deallocDecl = new MethodDeclaration(deallocElement);
deallocDecl.setHasDeclaration(false);
Block block = new Block();
deallocDecl.setBody(block);
List<Statement> stmts = block.getStatements();
if (hasFinalize) {
String clsName = nameTable.getFullName(type);
stmts.add(new NativeStatement("JreCheckFinalize(self, [" + clsName + " class]);"));
}
stmts.addAll(releaseStatements);
if (options.useReferenceCounting()) {
stmts.add(new ExpressionStatement(
new SuperMethodInvocation(new ExecutablePair(superDeallocElement))));
}
node.addBodyDeclaration(deallocDecl);
}
private boolean hasFinalizeMethod(TypeElement type) {
if (type == null || ElementUtil.getQualifiedName(type).equals("java.lang.Object")) {
return false;
}
for (ExecutableElement method : ElementUtil.getMethods(type)) {
if (ElementUtil.getName(method).equals(NameTable.FINALIZE_METHOD)
&& method.getParameters().isEmpty()) {
return true;
}
}
return hasFinalizeMethod(ElementUtil.getSuperclass(type));
}
private List<Statement> createReleaseStatements(AbstractTypeDeclaration node) {
List<Statement> statements = Lists.newArrayList();
for (VariableDeclarationFragment fragment : TreeUtil.getAllFields(node)) {
Statement releaseStmt = createRelease(fragment.getVariableElement());
if (releaseStmt != null) {
statements.add(releaseStmt);
}
}
return statements;
}
private Statement createRelease(VariableElement var) {
TypeMirror varType = var.asType();
if (ElementUtil.isStatic(var) || varType.getKind().isPrimitive()
|| ElementUtil.isWeakReference(var)) {
return null;
}
boolean isVolatile = ElementUtil.isVolatile(var);
boolean isRetainedWith = ElementUtil.isRetainedWithField(var);
String funcName = null;
if (isRetainedWith) {
funcName = isVolatile ? "JreVolatileRetainedWithRelease" : "JreRetainedWithRelease";
} else if (isVolatile) {
funcName = "JreReleaseVolatile";
} else if (options.useReferenceCounting()) {
funcName = "RELEASE_";
}
if (funcName == null) {
return null;
}
TypeMirror voidType = typeUtil.getVoid();
TypeMirror idType = TypeUtil.ID_TYPE;
FunctionElement element = new FunctionElement(funcName, voidType, null);
FunctionInvocation releaseInvocation = new FunctionInvocation(element, voidType);
if (isRetainedWith) {
element.addParameters(idType);
releaseInvocation.addArgument(
new ThisExpression(ElementUtil.getDeclaringClass(var).asType()));
}
element.addParameters(isVolatile ? TypeUtil.ID_PTR_TYPE : idType);
Expression arg = new SimpleName(var);
if (isVolatile) {
arg = new PrefixExpression(
new PointerType(varType), PrefixExpression.Operator.ADDRESS_OF, arg);
}
releaseInvocation.addArgument(arg);
return new ExpressionStatement(releaseInvocation);
}
}