lucene/src/java/org/apache/lucene/index/CompoundFileReader.java - lucene-solr - Git at Google

 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.Collection;
 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 (files: " + entries.keySet() + ")");

         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);
     }

     /** 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();
     }

     @Override
     public void sync(Collection<String> names) throws IOException {
     }

     /** 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);
           }
         }

     }

 }
	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.Collection;
	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 (files: " + entries.keySet() + ")");

	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);
	}

	/** 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();
	}

	@Override
	public void sync(Collection<String> names) throws IOException {
	}

	/** 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);
	}
	}

	}

	}