| /** |
| * 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.hadoop.mapred; |
| |
| import java.io.EOFException; |
| import java.io.IOException; |
| import java.io.InputStream; |
| |
| import org.apache.hadoop.fs.ChecksumException; |
| import org.apache.hadoop.io.IOUtils; |
| import org.apache.hadoop.util.DataChecksum; |
| /** |
| * A checksum input stream, used for IFiles. |
| * Used to validate the checksum of files created by {@link IFileOutputStream}. |
| * |
| * <FRAMEWORK-USE-ONLY> |
| * This method is intended only for use by the Map/Reduce framework and not |
| * for external users |
| * |
| */ |
| |
| public class IFileInputStream extends InputStream { |
| |
| private final InputStream in; //The input stream to be verified for checksum. |
| private final long length; //The total length of the input file |
| private final long dataLength; |
| private DataChecksum sum; |
| private long currentOffset = 0; |
| private final byte b[] = new byte[1]; |
| private byte csum[] = null; |
| private int checksumSize; |
| |
| private boolean disableChecksumValidation = false; |
| |
| /** |
| * Create a checksum input stream that reads |
| * @param in The input stream to be verified for checksum. |
| * @param len The length of the input stream including checksum bytes. |
| */ |
| public IFileInputStream(InputStream in, long len) { |
| this.in = in; |
| sum = DataChecksum.newDataChecksum(DataChecksum.CHECKSUM_CRC32, |
| Integer.MAX_VALUE); |
| checksumSize = sum.getChecksumSize(); |
| length = len; |
| dataLength = length - checksumSize; |
| } |
| |
| /** |
| * Close the input stream. Note that we need to read to the end of the |
| * stream to validate the checksum. |
| */ |
| @Override |
| public void close() throws IOException { |
| if (currentOffset < dataLength) { |
| byte[] t = new byte[Math.min((int) |
| (Integer.MAX_VALUE & (dataLength - currentOffset)), 32 * 1024)]; |
| while (currentOffset < dataLength) { |
| int n = read(t, 0, t.length); |
| if (0 == n) { |
| throw new EOFException("Could not validate checksum"); |
| } |
| } |
| } |
| in.close(); |
| } |
| |
| @Override |
| public long skip(long n) throws IOException { |
| throw new IOException("Skip not supported for IFileInputStream"); |
| } |
| |
| public long getPosition() { |
| return (currentOffset >= dataLength) ? dataLength : currentOffset; |
| } |
| |
| public long getSize() { |
| return checksumSize; |
| } |
| |
| /** |
| * Read bytes from the stream. |
| * At EOF, checksum is validated, but the checksum |
| * bytes are not passed back in the buffer. |
| */ |
| public int read(byte[] b, int off, int len) throws IOException { |
| |
| if (currentOffset >= dataLength) { |
| return -1; |
| } |
| |
| return doRead(b,off,len); |
| } |
| |
| /** |
| * Read bytes from the stream. |
| * At EOF, checksum is validated and sent back |
| * as the last four bytes of the buffer. The caller should handle |
| * these bytes appropriately |
| */ |
| public int readWithChecksum(byte[] b, int off, int len) throws IOException { |
| |
| if (currentOffset == length) { |
| return -1; |
| } |
| else if (currentOffset >= dataLength) { |
| // If the previous read drained off all the data, then just return |
| // the checksum now. Note that checksum validation would have |
| // happened in the earlier read |
| int lenToCopy = (int) (checksumSize - (currentOffset - dataLength)); |
| if (len < lenToCopy) { |
| lenToCopy = len; |
| } |
| System.arraycopy(csum, (int) (currentOffset - dataLength), b, off, |
| lenToCopy); |
| currentOffset += lenToCopy; |
| return lenToCopy; |
| } |
| |
| int bytesRead = doRead(b,off,len); |
| |
| if (currentOffset == dataLength) { |
| if (len >= bytesRead + checksumSize) { |
| System.arraycopy(csum, 0, b, off + bytesRead, checksumSize); |
| bytesRead += checksumSize; |
| currentOffset += checksumSize; |
| } |
| } |
| return bytesRead; |
| } |
| |
| private int doRead(byte[]b, int off, int len) throws IOException { |
| |
| // If we are trying to read past the end of data, just read |
| // the left over data |
| if (currentOffset + len > dataLength) { |
| len = (int) dataLength - (int)currentOffset; |
| } |
| |
| int bytesRead = in.read(b, off, len); |
| |
| if (bytesRead < 0) { |
| throw new ChecksumException("Checksum Error", 0); |
| } |
| |
| sum.update(b,off,bytesRead); |
| |
| currentOffset += bytesRead; |
| |
| if (disableChecksumValidation) { |
| return bytesRead; |
| } |
| |
| if (currentOffset == dataLength) { |
| // The last four bytes are checksum. Strip them and verify |
| csum = new byte[checksumSize]; |
| IOUtils.readFully(in, csum, 0, checksumSize); |
| if (!sum.compare(csum, 0)) { |
| throw new ChecksumException("Checksum Error", 0); |
| } |
| } |
| return bytesRead; |
| } |
| |
| |
| @Override |
| public int read() throws IOException { |
| b[0] = 0; |
| int l = read(b,0,1); |
| if (l < 0) return l; |
| |
| // Upgrade the b[0] to an int so as not to misinterpret the |
| // first bit of the byte as a sign bit |
| int result = 0xFF & b[0]; |
| return result; |
| } |
| |
| public byte[] getChecksum() { |
| return csum; |
| } |
| |
| void disableChecksumValidation() { |
| disableChecksumValidation = true; |
| } |
| } |