| /* |
| * 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.apache.jackrabbit.oak.segment.file.tar; |
| |
| import org.apache.jackrabbit.oak.segment.util.ReaderAtEnd; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.UUID; |
| import java.util.zip.CRC32; |
| |
| import static com.google.common.collect.Lists.newArrayListWithCapacity; |
| import static com.google.common.collect.Maps.newHashMapWithExpectedSize; |
| import static org.apache.jackrabbit.oak.segment.file.tar.TarConstants.GRAPH_MAGIC; |
| |
| public final class GraphLoader { |
| |
| private static final Logger log = LoggerFactory.getLogger(GraphLoader.class); |
| |
| private static final int FOOTER_SIZE = 16; |
| |
| private GraphLoader() { |
| } |
| |
| /** |
| * Loads the optional pre-compiled graph entry from the given tar file. |
| * |
| * @return the graph or {@code null} if one was not found |
| * @throws IOException if the tar file could not be read |
| */ |
| public static ByteBuffer loadGraph(ReaderAtEnd readerAtEnd) throws IOException { |
| ByteBuffer meta = readerAtEnd.readAtEnd(FOOTER_SIZE, FOOTER_SIZE); |
| |
| int crc32 = meta.getInt(); |
| int count = meta.getInt(); |
| int bytes = meta.getInt(); |
| int magic = meta.getInt(); |
| |
| if (magic != GRAPH_MAGIC) { |
| log.warn("Invalid graph magic number"); |
| return null; |
| } |
| |
| if (count < 0) { |
| log.warn("Invalid number of entries"); |
| return null; |
| } |
| |
| if (bytes < 4 + count * 34) { |
| log.warn("Invalid entry size"); |
| return null; |
| } |
| |
| ByteBuffer graph = readerAtEnd.readAtEnd(bytes, bytes); |
| |
| byte[] b = new byte[bytes - FOOTER_SIZE]; |
| |
| graph.mark(); |
| graph.get(b); |
| graph.reset(); |
| |
| CRC32 checksum = new CRC32(); |
| checksum.update(b); |
| |
| if (crc32 != (int) checksum.getValue()) { |
| log.warn("Invalid graph checksum in tar file"); |
| return null; |
| } |
| |
| return graph; |
| } |
| |
| public static Map<UUID, List<UUID>> parseGraph(ByteBuffer buffer) { |
| int nEntries = buffer.getInt(buffer.limit() - 12); |
| |
| Map<UUID, List<UUID>> graph = newHashMapWithExpectedSize(nEntries); |
| |
| for (int i = 0; i < nEntries; i++) { |
| long msb = buffer.getLong(); |
| long lsb = buffer.getLong(); |
| int nVertices = buffer.getInt(); |
| |
| List<UUID> vertices = newArrayListWithCapacity(nVertices); |
| |
| for (int j = 0; j < nVertices; j++) { |
| long vMsb = buffer.getLong(); |
| long vLsb = buffer.getLong(); |
| vertices.add(new UUID(vMsb, vLsb)); |
| } |
| |
| graph.put(new UUID(msb, lsb), vertices); |
| } |
| |
| return graph; |
| } |
| } |