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/*
* Copyright 2019 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.turbine.processing;
import static com.google.common.base.Preconditions.checkArgument;
import static java.util.Objects.requireNonNull;
import com.google.turbine.binder.bound.EnumConstantValue;
import com.google.turbine.binder.bound.TurbineAnnotationValue;
import com.google.turbine.binder.bound.TurbineClassValue;
import com.google.turbine.binder.bound.TypeBoundClass;
import com.google.turbine.model.Const;
import com.google.turbine.model.Const.ArrayInitValue;
import com.google.turbine.model.Const.Value;
import com.google.turbine.type.AnnoInfo;
import java.lang.annotation.Annotation;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.util.ArrayList;
import java.util.List;
import javax.lang.model.type.MirroredTypeException;
import javax.lang.model.type.MirroredTypesException;
import javax.lang.model.type.TypeMirror;
/** An {@link InvocationHandler} for reflectively accessing annotations. */
class TurbineAnnotationProxy implements InvocationHandler {
static <A extends Annotation> A create(
ModelFactory factory, Class<A> annotationType, AnnoInfo anno) {
ClassLoader loader = annotationType.getClassLoader();
if (loader == null) {
// annotation was loaded from the system classloader, e.g. java.lang.annotation.*
loader = factory.processorLoader();
}
return annotationType.cast(
Proxy.newProxyInstance(
loader,
new Class<?>[] {annotationType},
new TurbineAnnotationProxy(factory, loader, annotationType, anno)));
}
private final ModelFactory factory;
private final ClassLoader loader;
private final Class<?> annotationType;
private final AnnoInfo anno;
TurbineAnnotationProxy(
ModelFactory factory, ClassLoader loader, Class<?> annotationType, AnnoInfo anno) {
this.factory = factory;
this.loader = loader;
this.annotationType = annotationType;
this.anno = anno;
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) {
switch (method.getName()) {
case "hashCode":
checkArgument(args == null);
return anno.hashCode();
case "annotationType":
checkArgument(args == null);
return annotationType;
case "equals":
checkArgument(args.length == 1);
return proxyEquals(args[0]);
case "toString":
checkArgument(args == null);
return anno.toString();
default:
break;
}
Const value = anno.values().get(method.getName());
if (value != null) {
return constValue(method.getReturnType(), factory, loader, value);
}
for (TypeBoundClass.MethodInfo m : factory.getSymbol(anno.sym()).methods()) {
if (m.name().contentEquals(method.getName())) {
return constValue(method.getReturnType(), factory, loader, m.defaultValue());
}
}
throw new NoSuchMethodError(method.getName());
}
public boolean proxyEquals(Object other) {
if (!annotationType.isInstance(other)) {
return false;
}
if (!Proxy.isProxyClass(other.getClass())) {
return false;
}
InvocationHandler handler = Proxy.getInvocationHandler(other);
if (!(handler instanceof TurbineAnnotationProxy)) {
return false;
}
TurbineAnnotationProxy that = (TurbineAnnotationProxy) handler;
return anno.equals(that.anno);
}
static Object constValue(
Class<?> returnType, ModelFactory factory, ClassLoader loader, Const value) {
switch (value.kind()) {
case PRIMITIVE:
return ((Value) value).getValue();
case ARRAY:
return constArrayValue(returnType, factory, loader, (Const.ArrayInitValue) value);
case ENUM_CONSTANT:
return constEnumValue(loader, (EnumConstantValue) value);
case ANNOTATION:
return constAnnotationValue(factory, loader, (TurbineAnnotationValue) value);
case CLASS_LITERAL:
return constClassValue(factory, (TurbineClassValue) value);
}
throw new AssertionError(value.kind());
}
private static Object constArrayValue(
Class<?> returnType, ModelFactory factory, ClassLoader loader, ArrayInitValue value) {
Class<?> componentType = requireNonNull(returnType.getComponentType());
if (componentType.equals(Class.class)) {
List<TypeMirror> result = new ArrayList<>();
for (Const element : value.elements()) {
result.add(factory.asTypeMirror(((TurbineClassValue) element).type()));
}
throw new MirroredTypesException(result);
}
Object result = Array.newInstance(componentType, value.elements().size());
int idx = 0;
for (Const element : value.elements()) {
Object v = constValue(returnType, factory, loader, element);
Array.set(result, idx++, v);
}
return result;
}
@SuppressWarnings("unchecked") // Enum.class
private static Object constEnumValue(ClassLoader loader, EnumConstantValue value) {
Class<?> clazz;
try {
clazz = loader.loadClass(value.sym().owner().toString());
} catch (ClassNotFoundException e) {
throw new LinkageError(e.getMessage(), e);
}
return Enum.valueOf(clazz.asSubclass(Enum.class), value.sym().name());
}
private static Object constAnnotationValue(
ModelFactory factory, ClassLoader loader, TurbineAnnotationValue value) {
try {
String name = value.sym().binaryName().replace('/', '.');
Class<? extends Annotation> clazz =
Class.forName(name, false, loader).asSubclass(Annotation.class);
return create(factory, clazz, value.info());
} catch (ClassNotFoundException e) {
throw new LinkageError(e.getMessage(), e);
}
}
private static Object constClassValue(ModelFactory factory, TurbineClassValue value) {
throw new MirroredTypeException(factory.asTypeMirror(value.type()));
}
}
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