package org.infinispan.lucene.impl;
import java.io.IOException;
import org.apache.lucene.store.IndexOutput;
import org.infinispan.AdvancedCache;
import org.infinispan.Cache;
import org.infinispan.context.Flag;
import org.infinispan.lucene.ChunkCacheKey;
import org.infinispan.lucene.FileCacheKey;
import org.infinispan.lucene.FileMetadata;
import org.infinispan.util.logging.Log;
import org.infinispan.util.logging.LogFactory;
/**
* Responsible for writing to a <code>Directory</code>
*
* @since 4.0
* @author Sanne Grinovero
* @author Lukasz Moren
* @author Davide Di Somma
* @see org.apache.lucene.store.Directory
* @see org.apache.lucene.store.IndexInput
*/
public final class InfinispanIndexOutput extends IndexOutput {
private static final Log log = LogFactory.getLog(InfinispanIndexOutput.class);
private static final boolean trace = log.isTraceEnabled();
private final int bufferSize;
private final Cache<ChunkCacheKey, Object> chunksCache;
private final Cache<ChunkCacheKey, Object> chunksCacheForStorage;
private final AdvancedCache<FileCacheKey, FileMetadata> metadataCache;
private final FileMetadata file;
private final FileCacheKey fileKey;
private final FileListOperations fileOps;
private byte[] buffer;
/**
* First bytes are rewritten at close - we can minimize locking needs by flushing the first chunk
* only once (as final operation: so always keep a pointer to the first buffer)
*/
private byte[] firstChunkBuffer;
private int positionInBuffer = 0;
private long filePosition = 0;
private int currentChunkNumber = 0;
public InfinispanIndexOutput(final AdvancedCache<FileCacheKey, FileMetadata> metadataCache, final AdvancedCache<ChunkCacheKey, Object> chunksCache, final FileCacheKey fileKey, final int bufferSize, final FileListOperations fileList) {
this.metadataCache = metadataCache;
this.chunksCache = chunksCache;
this.chunksCacheForStorage = chunksCache.withFlags(Flag.IGNORE_RETURN_VALUES);
this.fileKey = fileKey;
this.bufferSize = bufferSize;
this.fileOps = fileList;
this.buffer = new byte[this.bufferSize];
this.firstChunkBuffer = buffer;
this.file = new FileMetadata(bufferSize);
if (trace) {
log.tracef("Opened new IndexOutput for file:%s in index: %s", fileKey.getFileName(), fileKey.getIndexName());
}
}
private byte[] getChunkById(FileCacheKey fileKey, int chunkNumber, int bufferSize) {
if (file.getNumberOfChunks() <= chunkNumber) {
return new byte[bufferSize];
}
ChunkCacheKey key = new ChunkCacheKey(fileKey.getIndexName(), fileKey.getFileName(), chunkNumber, bufferSize);
byte[] readBuffer = (byte[]) chunksCache.get(key);
if (readBuffer==null) {
return new byte[bufferSize];
}
else if (readBuffer.length == bufferSize) {
return readBuffer;
}
else {
byte[] newBuffer = new byte[bufferSize];
System.arraycopy(readBuffer, 0, newBuffer, 0, readBuffer.length);
return newBuffer;
}
}
private static int getPositionInBuffer(final long pos, final int bufferSize) {
return (int) (pos % bufferSize);
}
private static int getChunkNumberFromPosition(final long pos, final int bufferSize) {
return (int) ((pos) / (bufferSize));
}
private void newChunk() {
storeCurrentBuffer(false);// save data first
currentChunkNumber++;
// check if we have to create new chunk, or get already existing in cache for modification
buffer = getChunkById(fileKey, currentChunkNumber, bufferSize);
positionInBuffer = 0;
}
@Override
public final void writeByte(final byte b) {
if (isNewChunkNeeded()) {
newChunk();
}
buffer[positionInBuffer++] = b;
filePosition++;
}
@Override
public final void writeBytes(final byte[] b, final int offset, final int length) {
int writtenBytes = 0;
while (writtenBytes < length) {
if (isNewChunkNeeded()) {
newChunk();
}
int pieceLength = Math.min(bufferSize - positionInBuffer, length - writtenBytes);
System.arraycopy(b, offset + writtenBytes, buffer, positionInBuffer, pieceLength);
positionInBuffer += pieceLength;
filePosition += pieceLength;
writtenBytes += pieceLength;
}
}
private boolean isNewChunkNeeded() {
return (positionInBuffer == buffer.length);
}
@Override
public void flush() {
storeCurrentBuffer(false);
}
protected void storeCurrentBuffer(final boolean isClose) {
if (currentChunkNumber == 0 && ! isClose) {
//we don't store the first chunk until the close operation: this way
//we guarantee each chunk is written only once an minimize locking needs.
return;
}
// size changed, apply change to file header
resizeFileIfNeeded();
byte[] bufferToFlush = buffer;
boolean writingOnLastChunk = isWritingOnLastChunk();
if (writingOnLastChunk) {
int newBufferSize = (int) (file.getSize() % bufferSize);
if (newBufferSize != 0) {
bufferToFlush = new byte[newBufferSize];
System.arraycopy(buffer, 0, bufferToFlush, 0, newBufferSize);
}
}
// add chunk to cache
if ( ! writingOnLastChunk || this.positionInBuffer != 0) {
// store the current chunk
storeBufferAsChunk(bufferToFlush, currentChunkNumber);
}
}
/**
* @param bufferToFlush
* @param chunkNumber
*/
private void storeBufferAsChunk(final byte[] bufferToFlush, final int chunkNumber) {
ChunkCacheKey key = new ChunkCacheKey(fileKey.getIndexName(), fileKey.getFileName(), chunkNumber, bufferSize);
if (trace) log.tracef("Storing segment chunk: %s", key);
chunksCacheForStorage.put(key, bufferToFlush);
}
private void resizeFileIfNeeded() {
if (file.getSize() < filePosition) {
file.setSize(filePosition);
}
}
@Override
public void close() {
if (currentChunkNumber==0) {
//store current chunk, possibly resizing it
storeCurrentBuffer(true);
}
else {
//no need to resize first chunk, just store it:
storeBufferAsChunk(this.firstChunkBuffer, 0);
storeCurrentBuffer(true);
}
buffer = null;
firstChunkBuffer = null;
// override existing file header with updated accesstime
file.touch();
metadataCache.withFlags(Flag.IGNORE_RETURN_VALUES).put(fileKey, file);
fileOps.addFileName(this.fileKey.getFileName());
if (trace) {
log.tracef("Closed IndexOutput for %s", fileKey);
}
}
@Override
public long getFilePointer() {
return filePosition;
}
@Override
public void seek(final long pos) throws IOException {
final int requestedChunkNumber = getChunkNumberFromPosition(pos, bufferSize);
if (pos > file.getSize()) {
resizeFileIfNeeded();
if (pos > file.getSize()) // check again, might be fixed by the resize
throw new IOException(fileKey.getFileName() + ": seeking past end of file");
}
if (requestedChunkNumber != currentChunkNumber) {
storeCurrentBuffer(false);
if (requestedChunkNumber != 0) {
buffer = getChunkById(fileKey, requestedChunkNumber, bufferSize);
}
else {
buffer = firstChunkBuffer;
}
currentChunkNumber = requestedChunkNumber;
}
positionInBuffer = getPositionInBuffer(pos, bufferSize);
filePosition = pos;
}
@Override
public long length() {
return file.getSize();
}
private boolean isWritingOnLastChunk() {
final int lastChunkNumber = file.getNumberOfChunks() - 1;
return currentChunkNumber >= lastChunkNumber;
}
}