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/**
* 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.IOException;
import java.io.InputStream;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.Seekable;
import org.apache.hadoop.io.LongWritable;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.compress.CodecPool;
import org.apache.hadoop.io.compress.CompressionCodec;
import org.apache.hadoop.io.compress.CompressionCodecFactory;
import org.apache.hadoop.io.compress.Decompressor;
import org.apache.hadoop.io.compress.SplitCompressionInputStream;
import org.apache.hadoop.io.compress.SplittableCompressionCodec;
import org.apache.hadoop.mapreduce.lib.input.CompressedSplitLineReader;
import org.apache.hadoop.mapreduce.lib.input.SplitLineReader;
import org.apache.hadoop.mapreduce.lib.input.UncompressedSplitLineReader;
import io.prestosql.hadoop.$internal.org.slf4j.Logger;
import io.prestosql.hadoop.$internal.org.slf4j.LoggerFactory;
/**
* Treats keys as offset in file and value as line.
*/
@InterfaceAudience.LimitedPrivate({"MapReduce", "Pig"})
@InterfaceStability.Unstable
public class LineRecordReader implements RecordReader {
private static final Logger LOG =
LoggerFactory.getLogger(LineRecordReader.class.getName());
private CompressionCodecFactory compressionCodecs = null;
private long start;
private long pos;
private long end;
private SplitLineReader in;
private FSDataInputStream fileIn;
private final Seekable filePosition;
int maxLineLength;
private CompressionCodec codec;
private Decompressor decompressor;
/**
* A class that provides a line reader from an input stream.
* @deprecated Use {@link org.apache.hadoop.util.LineReader} instead.
*/
@Deprecated
public static class LineReader extends org.apache.hadoop.util.LineReader {
LineReader(InputStream in) {
super(in);
}
LineReader(InputStream in, int bufferSize) {
super(in, bufferSize);
}
public LineReader(InputStream in, Configuration conf) throws IOException {
super(in, conf);
}
LineReader(InputStream in, byte[] recordDelimiter) {
super(in, recordDelimiter);
}
LineReader(InputStream in, int bufferSize, byte[] recordDelimiter) {
super(in, bufferSize, recordDelimiter);
}
public LineReader(InputStream in, Configuration conf,
byte[] recordDelimiter) throws IOException {
super(in, conf, recordDelimiter);
}
}
public LineRecordReader(Configuration job,
FileSplit split) throws IOException {
this(job, split, null);
}
public LineRecordReader(Configuration job, FileSplit split,
byte[] recordDelimiter) throws IOException {
this.maxLineLength = job.getInt(org.apache.hadoop.mapreduce.lib.input.
LineRecordReader.MAX_LINE_LENGTH, Integer.MAX_VALUE);
start = split.getStart();
end = start + split.getLength();
final Path file = split.getPath();
compressionCodecs = new CompressionCodecFactory(job);
codec = compressionCodecs.getCodec(file);
// open the file and seek to the start of the split
final FileSystem fs = file.getFileSystem(job);
fileIn = fs.open(file);
if (isCompressedInput()) {
decompressor = CodecPool.getDecompressor(codec);
if (codec instanceof SplittableCompressionCodec) {
final SplitCompressionInputStream cIn =
((SplittableCompressionCodec)codec).createInputStream(
fileIn, decompressor, start, end,
SplittableCompressionCodec.READ_MODE.BYBLOCK);
in = new CompressedSplitLineReader(cIn, job, recordDelimiter);
start = cIn.getAdjustedStart();
end = cIn.getAdjustedEnd();
filePosition = cIn; // take pos from compressed stream
} else {
if (start != 0) {
// So we have a split that is part of a file stored using
// a Compression codec that cannot be split.
throw new IOException("Cannot seek in " +
codec.getClass().getSimpleName() + " compressed stream");
}
in = new SplitLineReader(codec.createInputStream(fileIn,
decompressor), job, recordDelimiter);
filePosition = fileIn;
}
} else {
fileIn.seek(start);
in = new UncompressedSplitLineReader(
fileIn, job, recordDelimiter, split.getLength());
filePosition = fileIn;
}
// If this is not the first split, we always throw away first record
// because we always (except the last split) read one extra line in
// next() method.
if (start != 0) {
start += in.readLine(new Text(), 0, maxBytesToConsume(start));
}
this.pos = start;
}
public LineRecordReader(InputStream in, long offset, long endOffset,
int maxLineLength) {
this(in, offset, endOffset, maxLineLength, null);
}
public LineRecordReader(InputStream in, long offset, long endOffset,
int maxLineLength, byte[] recordDelimiter) {
this.maxLineLength = maxLineLength;
this.in = new SplitLineReader(in, recordDelimiter);
this.start = offset;
this.pos = offset;
this.end = endOffset;
filePosition = null;
}
public LineRecordReader(InputStream in, long offset, long endOffset,
Configuration job)
throws IOException{
this(in, offset, endOffset, job, null);
}
public LineRecordReader(InputStream in, long offset, long endOffset,
Configuration job, byte[] recordDelimiter)
throws IOException{
this.maxLineLength = job.getInt(org.apache.hadoop.mapreduce.lib.input.
LineRecordReader.MAX_LINE_LENGTH, Integer.MAX_VALUE);
this.in = new SplitLineReader(in, job, recordDelimiter);
this.start = offset;
this.pos = offset;
this.end = endOffset;
filePosition = null;
}
public LongWritable createKey() {
return new LongWritable();
}
public Text createValue() {
return new Text();
}
private boolean isCompressedInput() {
return (codec != null);
}
private int maxBytesToConsume(long pos) {
return isCompressedInput()
? Integer.MAX_VALUE
: (int) Math.max(Math.min(Integer.MAX_VALUE, end - pos), maxLineLength);
}
private long getFilePosition() throws IOException {
long retVal;
if (isCompressedInput() && null != filePosition) {
retVal = filePosition.getPos();
} else {
retVal = pos;
}
return retVal;
}
private int skipUtfByteOrderMark(Text value) throws IOException {
// Strip BOM(Byte Order Mark)
// Text only support UTF-8, we only need to check UTF-8 BOM
// (0xEF,0xBB,0xBF) at the start of the text stream.
int newMaxLineLength = (int) Math.min(3L + (long) maxLineLength,
Integer.MAX_VALUE);
int newSize = in.readLine(value, newMaxLineLength, maxBytesToConsume(pos));
// Even we read 3 extra bytes for the first line,
// we won't alter existing behavior (no backwards incompat issue).
// Because the newSize is less than maxLineLength and
// the number of bytes copied to Text is always no more than newSize.
// If the return size from readLine is not less than maxLineLength,
// we will discard the current line and read the next line.
pos += newSize;
int textLength = value.getLength();
byte[] textBytes = value.getBytes();
if ((textLength >= 3) && (textBytes[0] == (byte)0xEF) &&
(textBytes[1] == (byte)0xBB) && (textBytes[2] == (byte)0xBF)) {
// find UTF-8 BOM, strip it.
LOG.info("Found UTF-8 BOM and skipped it");
textLength -= 3;
newSize -= 3;
if (textLength > 0) {
// It may work to use the same buffer and not do the copyBytes
textBytes = value.copyBytes();
value.set(textBytes, 3, textLength);
} else {
value.clear();
}
}
return newSize;
}
/** Read a line. */
public synchronized boolean next(LongWritable key, Text value)
throws IOException {
// We always read one extra line, which lies outside the upper
// split limit i.e. (end - 1)
while (getFilePosition() <= end || in.needAdditionalRecordAfterSplit()) {
key.set(pos);
int newSize = 0;
if (pos == 0) {
newSize = skipUtfByteOrderMark(value);
} else {
newSize = in.readLine(value, maxLineLength, maxBytesToConsume(pos));
pos += newSize;
}
if (newSize == 0) {
return false;
}
if (newSize < maxLineLength) {
return true;
}
// line too long. try again
LOG.info("Skipped line of size " + newSize + " at pos " + (pos - newSize));
}
return false;
}
/**
* Get the progress within the split
*/
public synchronized float getProgress() throws IOException {
if (start == end) {
return 0.0f;
} else {
return Math.min(1.0f, (getFilePosition() - start) / (float)(end - start));
}
}
public synchronized long getPos() throws IOException {
return pos;
}
public synchronized void close() throws IOException {
try {
if (in != null) {
in.close();
}
} finally {
if (decompressor != null) {
CodecPool.returnDecompressor(decompressor);
decompressor = null;
}
}
}
}