org.aotorrent.common.storage.FileStorage.java Source code

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Here is the source code for org.aotorrent.common.storage.FileStorage.java

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/*
 * Copyright 2014 Napolov Dmitry
 *
 * 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.aotorrent.common.storage;

import com.google.common.collect.Lists;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import org.aotorrent.common.TorrentFile;

import java.io.File;
import java.io.IOException;
import java.io.RandomAccessFile;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.Collection;
import java.util.List;

/**
 * User: dnapolov
 * Date: 11/25/13
 * Time: 6:17 PM
 */
public class FileStorage {

    private final List<TorrentFile> files;
    private final int pieceLength;

    public FileStorage(List<TorrentFile> files, int pieceLength) {
        this.files = files;
        this.pieceLength = pieceLength;
    }

    public void store(int pieceIndex, ByteBuf byteBuffer) throws IOException {
        Collection<StorageFilesInfo> storageFiles = getAffectedFiles(pieceIndex);

        for (StorageFilesInfo storageFile : storageFiles) {

            ByteBuf buf = Unpooled.buffer((int) storageFile.getLength());
            byteBuffer.getBytes((int) storageFile.getPieceOffset(), buf, (int) storageFile.getLength());

            final File file = storageFile.getFile();

            if (file.getParentFile() != null) {
                //noinspection ResultOfMethodCallIgnored
                file.getParentFile().mkdirs();
            }

            try (RandomAccessFile randomAccessFile = new RandomAccessFile(file.getCanonicalPath(), "rw")) {
                try (FileChannel fileChannel = randomAccessFile.getChannel()) {
                    fileChannel.position(storageFile.getFileOffset());
                    fileChannel.write(buf.nioBuffer());
                }
            }
        }
    }

    public ByteBuf read(int pieceIndex, int length) throws IOException {

        Collection<StorageFilesInfo> storageFiles = getAffectedFiles(pieceIndex);
        ByteBuffer buf = ByteBuffer.allocate(length);

        for (StorageFilesInfo storageFile : storageFiles) {
            try (RandomAccessFile randomAccessFile = new RandomAccessFile(storageFile.getFile(), "r")) {
                try (FileChannel fileChannel = randomAccessFile.getChannel()) {
                    ByteBuffer local = ByteBuffer.allocate((int) storageFile.getLength());
                    fileChannel.read(local, storageFile.getFileOffset());
                    local.flip();
                    buf.put(local);
                }
            }
        }
        buf.flip();
        return Unpooled.wrappedBuffer(buf);
    }

    private Collection<StorageFilesInfo> getAffectedFiles(int pieceIndex) {
        long pieceStartPosition = ((long) pieceIndex) * pieceLength;
        long pieceEndPosition = pieceStartPosition + pieceLength;
        long fileStartPosition = 0;
        long fileEndPosition;
        int fileIndex = 0;

        List<StorageFilesInfo> storageFilesInfos = Lists.newArrayList();

        while (fileIndex < files.size() && fileStartPosition < pieceEndPosition) {
            TorrentFile file = files.get(fileIndex);
            fileEndPosition = fileStartPosition + file.getLength();

            StorageFilesInfo sfi = null;

            if ((fileStartPosition <= pieceStartPosition) && (fileEndPosition > pieceStartPosition)) { // file starts earlier than piece, but included in it
                if (fileEndPosition >= pieceEndPosition) { // file takes whole piece
                    sfi = new StorageFilesInfo(new File(file.getPath()), 0, pieceStartPosition - fileStartPosition,
                            pieceLength);
                } else if (fileEndPosition < pieceEndPosition) { // file takes first part of piece
                    sfi = new StorageFilesInfo(new File(file.getPath()), 0, pieceStartPosition - fileStartPosition,
                            fileEndPosition - pieceStartPosition);
                }
            } else if ((fileStartPosition > pieceStartPosition) && (fileEndPosition < pieceEndPosition)) { // whole file is in piece
                sfi = new StorageFilesInfo(new File(file.getPath()), fileStartPosition - pieceStartPosition, 0,
                        file.getLength());
            } else if ((fileStartPosition > pieceStartPosition) && (fileEndPosition > pieceEndPosition)) { // file ends the piece
                sfi = new StorageFilesInfo(new File(file.getPath()), fileStartPosition - pieceStartPosition, 0,
                        pieceEndPosition - fileStartPosition);
            }

            if (sfi != null) {
                storageFilesInfos.add(sfi);
            }

            fileStartPosition = fileEndPosition;
            fileIndex++;
        }
        return storageFilesInfos;
    }

    private class StorageFilesInfo {

        private final File file;

        private final long pieceOffset;

        private final long fileOffset;

        private final long length;

        private StorageFilesInfo(File file, long pieceOffset, long fileOffset, long length) {
            this.file = file;
            this.pieceOffset = pieceOffset; //starting index of piece
            this.fileOffset = fileOffset;
            this.length = length;
        }

        public File getFile() {
            return file;
        }

        public long getPieceOffset() {
            return pieceOffset;
        }

        public long getFileOffset() {
            return fileOffset;
        }

        public long getLength() {
            return length;
        }
    }
}