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/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch 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.elasticsearch.common.compress;
import org.elasticsearch.common.Nullable;
import org.elasticsearch.common.bytes.BytesReference;
import org.elasticsearch.common.io.Streams;
import org.elasticsearch.common.io.stream.BytesStreamOutput;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.xcontent.XContentFactory;
import org.elasticsearch.common.xcontent.XContentType;
import java.io.IOException;
import java.util.Objects;
/**
*/
public class CompressorFactory {
public static final Compressor COMPRESSOR = new DeflateCompressor();
public static boolean isCompressed(BytesReference bytes) {
return compressor(bytes) != null;
}
@Nullable
public static Compressor compressor(BytesReference bytes) {
if (COMPRESSOR.isCompressed(bytes)) {
// bytes should be either detected as compressed or as xcontent,
// if we have bytes that can be either detected as compressed or
// as a xcontent, we have a problem
assert XContentFactory.xContentType(bytes) == null;
return COMPRESSOR;
}
XContentType contentType = XContentFactory.xContentType(bytes);
if (contentType == null) {
if (isAncient(bytes)) {
throw new IllegalStateException("unsupported compression: index was created before v2.0.0.beta1 and wasn't upgraded?");
}
throw new NotXContentException("Compressor detection can only be called on some xcontent bytes or compressed xcontent bytes");
}
return null;
}
/** true if the bytes were compressed with LZF: only used before elasticsearch 2.0 */
private static boolean isAncient(BytesReference bytes) {
return bytes.length() >= 3 &&
bytes.get(0) == 'Z' &&
bytes.get(1) == 'V' &&
(bytes.get(2) == 0 || bytes.get(2) == 1);
}
/**
* Uncompress the provided data, data can be detected as compressed using {@link #isCompressed(BytesReference)}.
* @throws NullPointerException a NullPointerException will be thrown when bytes is null
*/
public static BytesReference uncompressIfNeeded(BytesReference bytes) throws IOException {
Compressor compressor = compressor(Objects.requireNonNull(bytes, "the BytesReference must not be null"));
BytesReference uncompressed;
if (compressor != null) {
uncompressed = uncompress(bytes, compressor);
} else {
uncompressed = bytes;
}
return uncompressed;
}
/** Decompress the provided {@link BytesReference}. */
public static BytesReference uncompress(BytesReference bytes) throws IOException {
Compressor compressor = compressor(bytes);
if (compressor == null) {
throw new NotCompressedException();
}
return uncompress(bytes, compressor);
}
private static BytesReference uncompress(BytesReference bytes, Compressor compressor) throws IOException {
StreamInput compressed = compressor.streamInput(bytes.streamInput());
BytesStreamOutput bStream = new BytesStreamOutput();
Streams.copy(compressed, bStream);
compressed.close();
return bStream.bytes();
}
}