/**
* 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.fs.shell;
import java.io.IOException;
import java.io.InputStream;
import java.util.LinkedList;
import java.util.zip.GZIPInputStream;
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.FileStatus;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.shell.PathExceptions.PathIsDirectoryException;
import org.apache.hadoop.io.DataInputBuffer;
import org.apache.hadoop.io.DataOutputBuffer;
import org.apache.hadoop.io.IOUtils;
import org.apache.hadoop.io.SequenceFile;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableComparable;
import org.apache.hadoop.io.compress.CompressionCodec;
import org.apache.hadoop.io.compress.CompressionCodecFactory;
import org.apache.hadoop.util.ReflectionUtils;
/**
* Display contents of files
*/
@InterfaceAudience.Private
@InterfaceStability.Evolving
class Display extends FsCommand {
public static void registerCommands(CommandFactory factory) {
factory.addClass(Cat.class, "-cat");
factory.addClass(Text.class, "-text");
}
/**
* Displays file content to stdout
*/
public static class Cat extends Display {
public static final String NAME = "cat";
public static final String USAGE = "[-ignoreCrc] <src> ...";
public static final String DESCRIPTION =
"Fetch all files that match the file pattern <src> \n" +
"and display their content on stdout.\n";
private boolean verifyChecksum = true;
@Override
protected void processOptions(LinkedList<String> args)
throws IOException {
CommandFormat cf = new CommandFormat(1, Integer.MAX_VALUE, "ignoreCrc");
cf.parse(args);
verifyChecksum = !cf.getOpt("ignoreCrc");
}
@Override
protected void processPath(PathData item) throws IOException {
if (item.stat.isDirectory()) {
throw new PathIsDirectoryException(item.toString());
}
item.fs.setVerifyChecksum(verifyChecksum);
printToStdout(getInputStream(item));
}
private void printToStdout(InputStream in) throws IOException {
try {
IOUtils.copyBytes(in, out, getConf(), false);
} finally {
in.close();
}
}
protected InputStream getInputStream(PathData item) throws IOException {
return item.fs.open(item.path);
}
}
/**
* Same behavior as "-cat", but handles zip and TextRecordInputStream
* encodings.
*/
public static class Text extends Cat {
public static final String NAME = "text";
public static final String USAGE = Cat.USAGE;
public static final String DESCRIPTION =
"Takes a source file and outputs the file in text format.\n" +
"The allowed formats are zip and TextRecordInputStream.";
@Override
protected InputStream getInputStream(PathData item) throws IOException {
FSDataInputStream i = (FSDataInputStream)super.getInputStream(item);
// Check type of stream first
switch(i.readShort()) {
case 0x1f8b: { // RFC 1952
// Must be gzip
i.seek(0);
return new GZIPInputStream(i);
}
case 0x5345: { // 'S' 'E'
// Might be a SequenceFile
if (i.readByte() == 'Q') {
i.close();
return new TextRecordInputStream(item.stat);
}
}
default: {
// Check the type of compression instead, depending on Codec class's
// own detection methods, based on the provided path.
CompressionCodecFactory cf = new CompressionCodecFactory(getConf());
CompressionCodec codec = cf.getCodec(item.path);
if (codec != null) {
i.seek(0);
return codec.createInputStream(i);
}
break;
}
}
// File is non-compressed, or not a file container we know.
i.seek(0);
return i;
}
}
protected class TextRecordInputStream extends InputStream {
SequenceFile.Reader r;
WritableComparable<?> key;
Writable val;
DataInputBuffer inbuf;
DataOutputBuffer outbuf;
public TextRecordInputStream(FileStatus f) throws IOException {
final Path fpath = f.getPath();
final Configuration lconf = getConf();
r = new SequenceFile.Reader(lconf,
SequenceFile.Reader.file(fpath));
key = ReflectionUtils.newInstance(
r.getKeyClass().asSubclass(WritableComparable.class), lconf);
val = ReflectionUtils.newInstance(
r.getValueClass().asSubclass(Writable.class), lconf);
inbuf = new DataInputBuffer();
outbuf = new DataOutputBuffer();
}
public int read() throws IOException {
int ret;
if (null == inbuf || -1 == (ret = inbuf.read())) {
if (!r.next(key, val)) {
return -1;
}
byte[] tmp = key.toString().getBytes();
outbuf.write(tmp, 0, tmp.length);
outbuf.write('\t');
tmp = val.toString().getBytes();
outbuf.write(tmp, 0, tmp.length);
outbuf.write('\n');
inbuf.reset(outbuf.getData(), outbuf.getLength());
outbuf.reset();
ret = inbuf.read();
}
return ret;
}
public void close() throws IOException {
r.close();
super.close();
}
}
}