/*
* 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.jclouds.glacier.util;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import java.io.IOException;
import java.io.InputStream;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import org.jclouds.io.Payload;
import com.google.common.base.Objects;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableList.Builder;
import com.google.common.collect.ImmutableSortedMap;
import com.google.common.hash.HashCode;
import com.google.common.hash.Hashing;
import com.google.common.hash.HashingInputStream;
import com.google.common.io.ByteStreams;
import com.google.common.io.Closeables;
public final class TreeHash {
private static final int CHUNK_SIZE = 1024 * 1024;
private final HashCode treeHash;
private final HashCode linearHash;
private TreeHash(HashCode treeHash, HashCode linearHash) {
this.treeHash = checkNotNull(treeHash, "treeHash");
this.linearHash = checkNotNull(linearHash, "linearHash");
}
public HashCode getLinearHash() {
return linearHash;
}
public HashCode getTreeHash() {
return treeHash;
}
@Override
public int hashCode() {
return Objects.hashCode(this.treeHash, this.linearHash);
}
@Override
public boolean equals(Object obj) {
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
TreeHash other = (TreeHash) obj;
return Objects.equal(this.treeHash, other.treeHash) && Objects.equal(this.linearHash, other.linearHash);
}
@Override
public String toString() {
return "TreeHash [treeHash=" + treeHash + ", linearHash=" + linearHash + "]";
}
private static HashCode hashList(Collection<HashCode> hashList) {
Builder<HashCode> result = ImmutableList.builder();
while (hashList.size() > 1) {
//Hash pairs of values and add them to the result list.
for (Iterator<HashCode> it = hashList.iterator(); it.hasNext();) {
HashCode hc1 = it.next();
if (it.hasNext()) {
HashCode hc2 = it.next();
result.add(Hashing.sha256().newHasher()
.putBytes(hc1.asBytes())
.putBytes(hc2.asBytes())
.hash());
} else {
result.add(hc1);
}
}
hashList = result.build();
result = ImmutableList.builder();
}
return hashList.iterator().next();
}
/**
* Builds the Hash and the TreeHash values of the payload.
*
* @return The calculated TreeHash.
* @see <a href="http://docs.aws.amazon.com/amazonglacier/latest/dev/checksum-calculations.html" />
*/
public static TreeHash buildTreeHashFromPayload(Payload payload) throws IOException {
InputStream is = null;
try {
is = checkNotNull(payload, "payload").openStream();
Builder<HashCode> list = ImmutableList.builder();
HashingInputStream linearHis = new HashingInputStream(Hashing.sha256(), is);
while (true) {
HashingInputStream chunkedHis = new HashingInputStream(
Hashing.sha256(), ByteStreams.limit(linearHis, CHUNK_SIZE));
long count = ByteStreams.copy(chunkedHis, ByteStreams.nullOutputStream());
if (count == 0) {
break;
}
list.add(chunkedHis.hash());
}
//The result list contains exactly one element now.
return new TreeHash(hashList(list.build()), linearHis.hash());
} finally {
Closeables.closeQuietly(is);
}
}
/**
* Builds a TreeHash based on a map of hashed chunks.
*
* @return The calculated TreeHash.
* @see <a href="http://docs.aws.amazon.com/amazonglacier/latest/dev/checksum-calculations.html" />
*/
public static HashCode buildTreeHashFromMap(Map<Integer, HashCode> map) {
checkArgument(!map.isEmpty(), "The map cannot be empty.");
return hashList(ImmutableSortedMap.copyOf(map).values());
}
}