/**
* 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
* "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.jooby.internal;
import java.io.InputStream;
import java.lang.reflect.Constructor;
import java.lang.reflect.Executable;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import org.jooby.Env;
import org.objectweb.asm.ClassReader;
import org.objectweb.asm.ClassVisitor;
import org.objectweb.asm.Label;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
import org.objectweb.asm.Type;
import com.google.common.base.Throwables;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.CacheLoader;
import com.google.common.cache.LoadingCache;
import com.google.common.io.Closeables;
import com.google.common.io.Resources;
import com.google.common.util.concurrent.UncheckedExecutionException;
public class RouteMetadata implements ParameterNameProvider {
private static final String[] NO_ARG = new String[0];
private final LoadingCache<Class<?>, Map<String, Object>> cache;
public RouteMetadata(final Env env) {
CacheLoader<Class<?>, Map<String, Object>> loader = CacheLoader
.from(RouteMetadata::extractMetadata);
cache = env.name().equals("dev")
? CacheBuilder.newBuilder().maximumSize(0).build(loader)
: CacheBuilder.newBuilder().build(loader);
}
@Override
public String[] names(final Executable exec) {
Map<String, Object> md = md(exec);
String key = paramsKey(exec);
return (String[]) md.get(key);
}
public int startAt(final Executable exec) {
Map<String, Object> md = md(exec);
return (Integer) md.getOrDefault(startAtKey(exec), -1);
}
private Map<String, Object> md(final Executable exec) {
try {
return cache.getUnchecked(exec.getDeclaringClass());
} catch (UncheckedExecutionException ex) {
throw Throwables.propagate(ex.getCause());
}
}
private static Map<String, Object> extractMetadata(final Class<?> owner) {
InputStream stream = null;
try {
Map<String, Object> md = new HashMap<>();
stream = Resources.getResource(owner, classfile(owner)).openStream();
new ClassReader(stream).accept(visitor(md), 0);
return md;
} catch (Exception ex) {
// won't happen, but...
throw new IllegalStateException("Can't read class: " + owner.getName(), ex);
} finally {
Closeables.closeQuietly(stream);
}
}
private static String classfile(final Class<?> owner) {
StringBuilder sb = new StringBuilder();
Class<?> dc = owner.getDeclaringClass();
while (dc != null) {
sb.insert(0, dc.getSimpleName()).append("$");
dc = dc.getDeclaringClass();
}
sb.append(owner.getSimpleName());
sb.append(".class");
return sb.toString();
}
private static ClassVisitor visitor(final Map<String, Object> md) {
return new ClassVisitor(Opcodes.ASM5) {
@Override
public MethodVisitor visitMethod(final int access, final String name,
final String desc, final String signature, final String[] exceptions) {
boolean isPublic = ((access & Opcodes.ACC_PUBLIC) > 0) ? true : false;
boolean isStatic = ((access & Opcodes.ACC_STATIC) > 0) ? true : false;
if (!isPublic || isStatic) {
// ignore
return null;
}
final String seed = name + desc;
Type[] args = Type.getArgumentTypes(desc);
String[] names = args.length == 0 ? NO_ARG : new String[args.length];
md.put(paramsKey(seed), names);
int minIdx = ((access & Opcodes.ACC_STATIC) > 0) ? 0 : 1;
int maxIdx = Arrays.stream(args).mapToInt(Type::getSize).sum();
return new MethodVisitor(Opcodes.ASM5) {
private int i = 0;
private boolean skipLocalTable = false;
@Override
public void visitParameter(final String name, final int access) {
skipLocalTable = true;
// save current parameter
names[i] = name;
// move to next
i += 1;
}
@Override
public void visitLineNumber(final int line, final Label start) {
// save line number
md.putIfAbsent(startAtKey(seed), line);
}
@Override
public void visitLocalVariable(final String name, final String desc,
final String signature,
final Label start, final Label end, final int index) {
if (!skipLocalTable) {
if (index >= minIdx && index <= maxIdx) {
// save current parameter
names[i] = name;
// move to next
i += 1;
}
}
}
};
}
};
}
private static String paramsKey(final Executable exec) {
return paramsKey(key(exec));
}
private static String paramsKey(final String key) {
return key + ".params";
}
private static String startAtKey(final Executable exec) {
return startAtKey(key(exec));
}
private static String startAtKey(final String key) {
return key + ".startAt";
}
@SuppressWarnings("rawtypes")
private static String key(final Executable exec) {
if (exec instanceof Method) {
return exec.getName() + Type.getMethodDescriptor((Method) exec);
} else {
return "<init>" + Type.getConstructorDescriptor((Constructor) exec);
}
}
}