package org.apache.lucene.index;
/**
* 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.
*/
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.IndexInput;
import org.apache.lucene.store.BufferedIndexInput;
import org.apache.lucene.store.IndexOutput;
import org.apache.lucene.store.Lock;
import java.util.HashMap;
import java.io.FileNotFoundException;
import java.io.IOException;
/**
* Class for accessing a compound stream.
* This class implements a directory, but is limited to only read operations.
* Directory methods that would normally modify data throw an exception.
* @lucene.experimental
*/
public class CompoundFileReader extends Directory {
private int readBufferSize;
private static final class FileEntry {
long offset;
long length;
}
// Base info
private Directory directory;
private String fileName;
private IndexInput stream;
private HashMap<String,FileEntry> entries = new HashMap<String,FileEntry>();
public CompoundFileReader(Directory dir, String name) throws IOException {
this(dir, name, BufferedIndexInput.BUFFER_SIZE);
}
public CompoundFileReader(Directory dir, String name, int readBufferSize) throws IOException {
directory = dir;
fileName = name;
this.readBufferSize = readBufferSize;
boolean success = false;
try {
stream = dir.openInput(name, readBufferSize);
// read the first VInt. If it is negative, it's the version number
// otherwise it's the count (pre-3.1 indexes)
int firstInt = stream.readVInt();
final int count;
final boolean stripSegmentName;
if (firstInt < CompoundFileWriter.FORMAT_PRE_VERSION) {
if (firstInt < CompoundFileWriter.FORMAT_CURRENT) {
throw new CorruptIndexException("Incompatible format version: "
+ firstInt + " expected " + CompoundFileWriter.FORMAT_CURRENT);
}
// It's a post-3.1 index, read the count.
count = stream.readVInt();
stripSegmentName = false;
} else {
count = firstInt;
stripSegmentName = true;
}
// read the directory and init files
FileEntry entry = null;
for (int i=0; i<count; i++) {
long offset = stream.readLong();
String id = stream.readString();
if (stripSegmentName) {
// Fix the id to not include the segment names. This is relevant for
// pre-3.1 indexes.
id = IndexFileNames.stripSegmentName(id);
}
if (entry != null) {
// set length of the previous entry
entry.length = offset - entry.offset;
}
entry = new FileEntry();
entry.offset = offset;
entries.put(id, entry);
}
// set the length of the final entry
if (entry != null) {
entry.length = stream.length() - entry.offset;
}
success = true;
} finally {
if (!success && (stream != null)) {
try {
stream.close();
} catch (IOException e) { }
}
}
}
public Directory getDirectory() {
return directory;
}
public String getName() {
return fileName;
}
@Override
public synchronized void close() throws IOException {
if (stream == null)
throw new IOException("Already closed");
entries.clear();
stream.close();
stream = null;
}
@Override
public synchronized IndexInput openInput(String id)
throws IOException
{
// Default to readBufferSize passed in when we were opened
return openInput(id, readBufferSize);
}
@Override
public synchronized IndexInput openInput(String id, int readBufferSize)
throws IOException
{
if (stream == null)
throw new IOException("Stream closed");
id = IndexFileNames.stripSegmentName(id);
FileEntry entry = entries.get(id);
if (entry == null)
throw new IOException("No sub-file with id " + id + " found");
return new CSIndexInput(stream, entry.offset, entry.length, readBufferSize);
}
/** Returns an array of strings, one for each file in the directory. */
@Override
public String[] listAll() {
String[] res = entries.keySet().toArray(new String[entries.size()]);
// Add the segment name
String seg = fileName.substring(0, fileName.indexOf('.'));
for (int i = 0; i < res.length; i++) {
res[i] = seg + res[i];
}
return res;
}
/** Returns true iff a file with the given name exists. */
@Override
public boolean fileExists(String name) {
return entries.containsKey(IndexFileNames.stripSegmentName(name));
}
/** Returns the time the compound file was last modified. */
@Override
public long fileModified(String name) throws IOException {
return directory.fileModified(fileName);
}
/** Set the modified time of the compound file to now. */
@Override
public void touchFile(String name) throws IOException {
directory.touchFile(fileName);
}
/** Not implemented
* @throws UnsupportedOperationException */
@Override
public void deleteFile(String name)
{
throw new UnsupportedOperationException();
}
/** Not implemented
* @throws UnsupportedOperationException */
public void renameFile(String from, String to)
{
throw new UnsupportedOperationException();
}
/** Returns the length of a file in the directory.
* @throws IOException if the file does not exist */
@Override
public long fileLength(String name) throws IOException {
FileEntry e = entries.get(IndexFileNames.stripSegmentName(name));
if (e == null)
throw new FileNotFoundException(name);
return e.length;
}
/** Not implemented
* @throws UnsupportedOperationException */
@Override
public IndexOutput createOutput(String name)
{
throw new UnsupportedOperationException();
}
/** Not implemented
* @throws UnsupportedOperationException */
@Override
public Lock makeLock(String name)
{
throw new UnsupportedOperationException();
}
/** Implementation of an IndexInput that reads from a portion of the
* compound file. The visibility is left as "package" *only* because
* this helps with testing since JUnit test cases in a different class
* can then access package fields of this class.
*/
static final class CSIndexInput extends BufferedIndexInput {
IndexInput base;
long fileOffset;
long length;
CSIndexInput(final IndexInput base, final long fileOffset, final long length)
{
this(base, fileOffset, length, BufferedIndexInput.BUFFER_SIZE);
}
CSIndexInput(final IndexInput base, final long fileOffset, final long length, int readBufferSize)
{
super(readBufferSize);
this.base = (IndexInput)base.clone();
this.fileOffset = fileOffset;
this.length = length;
}
@Override
public Object clone() {
CSIndexInput clone = (CSIndexInput)super.clone();
clone.base = (IndexInput)base.clone();
clone.fileOffset = fileOffset;
clone.length = length;
return clone;
}
/** Expert: implements buffer refill. Reads bytes from the current
* position in the input.
* @param b the array to read bytes into
* @param offset the offset in the array to start storing bytes
* @param len the number of bytes to read
*/
@Override
protected void readInternal(byte[] b, int offset, int len)
throws IOException
{
long start = getFilePointer();
if(start + len > length)
throw new IOException("read past EOF");
base.seek(fileOffset + start);
base.readBytes(b, offset, len, false);
}
/** Expert: implements seek. Sets current position in this file, where
* the next {@link #readInternal(byte[],int,int)} will occur.
* @see #readInternal(byte[],int,int)
*/
@Override
protected void seekInternal(long pos) {}
/** Closes the stream to further operations. */
@Override
public void close() throws IOException {
base.close();
}
@Override
public long length() {
return length;
}
@Override
public void copyBytes(IndexOutput out, long numBytes) throws IOException {
// Copy first whatever is in the buffer
numBytes -= flushBuffer(out, numBytes);
// If there are more bytes left to copy, delegate the copy task to the
// base IndexInput, in case it can do an optimized copy.
if (numBytes > 0) {
long start = getFilePointer();
if (start + numBytes > length) {
throw new IOException("read past EOF");
}
base.seek(fileOffset + start);
base.copyBytes(out, numBytes);
}
}
}
}