/*
* Copyright 2016 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.gradle.internal.classloader;
import com.google.common.base.Charsets;
import com.google.common.hash.HashCode;
import com.google.common.hash.Hasher;
import com.google.common.hash.Hashing;
import org.gradle.api.Nullable;
import java.util.Map;
import java.util.WeakHashMap;
public class ConfigurableClassLoaderHierarchyHasher implements ClassLoaderHierarchyHasher {
private final Map<ClassLoader, byte[]> knownClassLoaders;
private final ClassLoaderHasher classLoaderHasher;
public ConfigurableClassLoaderHierarchyHasher(Map<ClassLoader, String> knownClassLoaders, ClassLoaderHasher classLoaderHasher) {
this.classLoaderHasher = classLoaderHasher;
Map<ClassLoader, byte[]> hashes = new WeakHashMap<ClassLoader, byte[]>();
for (Map.Entry<ClassLoader, String> entry : knownClassLoaders.entrySet()) {
hashes.put(entry.getKey(), entry.getValue().getBytes(Charsets.UTF_8));
}
this.knownClassLoaders = hashes;
}
@Nullable
@Override
public HashCode getClassLoaderHash(ClassLoader classLoader) {
Visitor visitor = new Visitor();
visitor.visit(classLoader);
return visitor.getHash();
}
private class Visitor extends ClassLoaderVisitor {
private final Hasher hasher = Hashing.md5().newHasher();
private boolean foundUnknown;
@Override
public void visit(ClassLoader classLoader) {
if (addToHash(classLoader)) {
super.visit(classLoader);
}
}
public HashCode getHash() {
return foundUnknown ? null : hasher.hash();
}
private boolean addToHash(ClassLoader cl) {
byte[] knownId = knownClassLoaders.get(cl);
if (knownId != null) {
hasher.putBytes(knownId);
return false;
}
if (cl instanceof CachingClassLoader || cl instanceof MultiParentClassLoader) {
return true;
}
HashCode hash = classLoaderHasher.getHash(cl);
if (hash != null) {
hasher.putBytes(hash.asBytes());
return true;
}
foundUnknown = true;
return false;
}
}
}