| /* |
| * 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 static com.google.common.base.Preconditions.checkState; |
| import static java.lang.Boolean.getBoolean; |
| import static java.nio.channels.FileChannel.MapMode.READ_ONLY; |
| import static org.apache.jackrabbit.oak.commons.IOUtils.readFully; |
| |
| import java.io.EOFException; |
| import java.io.IOException; |
| import java.io.RandomAccessFile; |
| import java.nio.ByteBuffer; |
| import java.nio.MappedByteBuffer; |
| import java.nio.channels.FileChannel; |
| |
| /** |
| * A wrapper around either memory mapped files or random access files, to allow |
| * reading from a file. |
| */ |
| abstract class FileAccess { |
| |
| private static final boolean OFF_HEAP = getBoolean("access.off.heap"); |
| |
| abstract boolean isMemoryMapped(); |
| |
| abstract int length() throws IOException; |
| |
| abstract ByteBuffer read(int position, int length) throws IOException; |
| |
| abstract void close() throws IOException; |
| |
| //-----------------------------------------------------------< private >-- |
| |
| /** |
| * The implementation that uses memory mapped files. |
| */ |
| static class Mapped extends FileAccess { |
| |
| private final RandomAccessFile file; |
| |
| private MappedByteBuffer buffer; |
| |
| Mapped(RandomAccessFile file) throws IOException { |
| this.file = file; |
| this.buffer = file.getChannel().map(READ_ONLY, 0, file.length()); |
| } |
| |
| @Override |
| boolean isMemoryMapped() { |
| return true; |
| } |
| |
| @Override |
| public int length() { |
| return buffer.remaining(); |
| } |
| |
| @Override |
| public ByteBuffer read(int position, int length) { |
| ByteBuffer entry = buffer.asReadOnlyBuffer(); |
| entry.position(entry.position() + position); |
| entry.limit(entry.position() + length); |
| return entry.slice(); |
| } |
| |
| @Override |
| public void close() throws IOException { |
| buffer = null; |
| file.close(); |
| } |
| |
| } |
| |
| /** |
| * The implementation that uses random access file (reads are synchronized). |
| */ |
| static class Random extends FileAccess { |
| |
| private final RandomAccessFile file; |
| private final FileChannel channel; |
| |
| Random(RandomAccessFile file) { |
| this.file = file; |
| this.channel = file.getChannel(); |
| } |
| |
| @Override |
| boolean isMemoryMapped() { |
| return false; |
| } |
| |
| @Override |
| public synchronized int length() throws IOException { |
| long length = file.length(); |
| checkState(length < Integer.MAX_VALUE); |
| return (int) length; |
| } |
| |
| @Override |
| public synchronized ByteBuffer read(int position, int length) |
| throws IOException { |
| ByteBuffer entry; |
| if (OFF_HEAP) { |
| entry = ByteBuffer.allocateDirect(length); |
| } else { |
| entry = ByteBuffer.allocate(length); |
| } |
| if (readFully(channel, position, entry) < length) { |
| throw new EOFException(); |
| } |
| entry.flip(); |
| return entry; |
| } |
| |
| @Override |
| public synchronized void close() throws IOException { |
| file.close(); |
| } |
| |
| } |
| |
| } |