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 java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.IOContext;
import org.apache.lucene.util.IOUtils;
final class StandardDirectoryReader extends DirectoryReader {
private final IndexWriter writer;
private final SegmentInfos segmentInfos;
private final boolean applyAllDeletes;
/** called only from static open() methods */
StandardDirectoryReader(Directory directory, AtomicReader[] readers, IndexWriter writer,
SegmentInfos sis, boolean applyAllDeletes) {
super(directory, readers);
this.writer = writer;
this.segmentInfos = sis;
this.applyAllDeletes = applyAllDeletes;
}
/** called from DirectoryReader.open(...) methods */
static DirectoryReader open(final Directory directory, final IndexCommit commit) throws IOException {
return (DirectoryReader) new SegmentInfos.FindSegmentsFile(directory) {
@Override
protected Object doBody(String segmentFileName) throws IOException {
SegmentInfos sis = new SegmentInfos();
sis.read(directory, segmentFileName);
final SegmentReader[] readers = new SegmentReader[sis.size()];
for (int i = sis.size()-1; i >= 0; i--) {
IOException prior = null;
boolean success = false;
try {
readers[i] = new SegmentReader(sis.info(i), IOContext.READ);
success = true;
} catch(IOException ex) {
prior = ex;
} finally {
if (!success) {
IOUtils.closeWhileHandlingException(prior, readers);
}
}
}
return new StandardDirectoryReader(directory, readers, null, sis, false);
}
}.run(commit);
}
/** Used by near real-time search */
static DirectoryReader open(IndexWriter writer, SegmentInfos infos, boolean applyAllDeletes) throws IOException {
// IndexWriter synchronizes externally before calling
// us, which ensures infos will not change; so there's
// no need to process segments in reverse order
final int numSegments = infos.size();
List<SegmentReader> readers = new ArrayList<>();
final Directory dir = writer.getDirectory();
final SegmentInfos segmentInfos = infos.clone();
int infosUpto = 0;
boolean success = false;
try {
for (int i = 0; i < numSegments; i++) {
// NOTE: important that we use infos not
// segmentInfos here, so that we are passing the
// actual instance of SegmentInfoPerCommit in
// IndexWriter's segmentInfos:
final SegmentCommitInfo info = infos.info(i);
assert info.info.dir == dir;
final ReadersAndUpdates rld = writer.readerPool.get(info, true);
try {
final SegmentReader reader = rld.getReadOnlyClone(IOContext.READ);
if (reader.numDocs() > 0 || writer.getKeepFullyDeletedSegments()) {
// Steal the ref:
readers.add(reader);
infosUpto++;
} else {
reader.decRef();
segmentInfos.remove(infosUpto);
}
} finally {
writer.readerPool.release(rld);
}
}
writer.incRefDeleter(segmentInfos);
StandardDirectoryReader result = new StandardDirectoryReader(dir,
readers.toArray(new SegmentReader[readers.size()]), writer,
segmentInfos, applyAllDeletes);
success = true;
return result;
} finally {
if (!success) {
for (SegmentReader r : readers) {
try {
r.decRef();
} catch (Throwable th) {
// ignore any exception that is thrown here to not mask any original
// exception.
}
}
}
}
}
/** This constructor is only used for {@link #doOpenIfChanged(SegmentInfos)} */
private static DirectoryReader open(Directory directory, SegmentInfos infos, List<? extends AtomicReader> oldReaders) throws IOException {
// we put the old SegmentReaders in a map, that allows us
// to lookup a reader using its segment name
final Map<String,Integer> segmentReaders = new HashMap<>();
if (oldReaders != null) {
// create a Map SegmentName->SegmentReader
for (int i = 0, c = oldReaders.size(); i < c; i++) {
final SegmentReader sr = (SegmentReader) oldReaders.get(i);
segmentReaders.put(sr.getSegmentName(), Integer.valueOf(i));
}
}
SegmentReader[] newReaders = new SegmentReader[infos.size()];
// remember which readers are shared between the old and the re-opened
// DirectoryReader - we have to incRef those readers
boolean[] readerShared = new boolean[infos.size()];
for (int i = infos.size() - 1; i>=0; i--) {
// find SegmentReader for this segment
Integer oldReaderIndex = segmentReaders.get(infos.info(i).info.name);
if (oldReaderIndex == null) {
// this is a new segment, no old SegmentReader can be reused
newReaders[i] = null;
} else {
// there is an old reader for this segment - we'll try to reopen it
newReaders[i] = (SegmentReader) oldReaders.get(oldReaderIndex.intValue());
}
boolean success = false;
Throwable prior = null;
try {
SegmentReader newReader;
if (newReaders[i] == null || infos.info(i).info.getUseCompoundFile() != newReaders[i].getSegmentInfo().info.getUseCompoundFile()) {
// this is a new reader; in case we hit an exception we can close it safely
newReader = new SegmentReader(infos.info(i), IOContext.READ);
readerShared[i] = false;
newReaders[i] = newReader;
} else {
if (newReaders[i].getSegmentInfo().getDelGen() == infos.info(i).getDelGen()
&& newReaders[i].getSegmentInfo().getFieldInfosGen() == infos.info(i).getFieldInfosGen()) {
// No change; this reader will be shared between
// the old and the new one, so we must incRef
// it:
readerShared[i] = true;
newReaders[i].incRef();
} else {
// there are changes to the reader, either liveDocs or DV updates
readerShared[i] = false;
// Steal the ref returned by SegmentReader ctor:
assert infos.info(i).info.dir == newReaders[i].getSegmentInfo().info.dir;
assert infos.info(i).hasDeletions() || infos.info(i).hasFieldUpdates();
if (newReaders[i].getSegmentInfo().getDelGen() == infos.info(i).getDelGen()) {
// only DV updates
newReaders[i] = new SegmentReader(infos.info(i), newReaders[i], newReaders[i].getLiveDocs(), newReaders[i].numDocs());
} else {
// both DV and liveDocs have changed
newReaders[i] = new SegmentReader(infos.info(i), newReaders[i]);
}
}
}
success = true;
} catch (Throwable ex) {
prior = ex;
} finally {
if (!success) {
for (i++; i < infos.size(); i++) {
if (newReaders[i] != null) {
try {
if (!readerShared[i]) {
// this is a new subReader that is not used by the old one,
// we can close it
newReaders[i].close();
} else {
// this subReader is also used by the old reader, so instead
// closing we must decRef it
newReaders[i].decRef();
}
} catch (Throwable t) {
if (prior == null) prior = t;
}
}
}
}
// throw the first exception
IOUtils.reThrow(prior);
}
}
return new StandardDirectoryReader(directory, newReaders, null, infos, false);
}
@Override
public String toString() {
final StringBuilder buffer = new StringBuilder();
buffer.append(getClass().getSimpleName());
buffer.append('(');
final String segmentsFile = segmentInfos.getSegmentsFileName();
if (segmentsFile != null) {
buffer.append(segmentsFile).append(":").append(segmentInfos.getVersion());
}
if (writer != null) {
buffer.append(":nrt");
}
for (final AtomicReader r : getSequentialSubReaders()) {
buffer.append(' ');
buffer.append(r);
}
buffer.append(')');
return buffer.toString();
}
@Override
protected DirectoryReader doOpenIfChanged() throws IOException {
return doOpenIfChanged((IndexCommit) null);
}
@Override
protected DirectoryReader doOpenIfChanged(final IndexCommit commit) throws IOException {
ensureOpen();
// If we were obtained by writer.getReader(), re-ask the
// writer to get a new reader.
if (writer != null) {
return doOpenFromWriter(commit);
} else {
return doOpenNoWriter(commit);
}
}
@Override
protected DirectoryReader doOpenIfChanged(IndexWriter writer, boolean applyAllDeletes) throws IOException {
ensureOpen();
if (writer == this.writer && applyAllDeletes == this.applyAllDeletes) {
return doOpenFromWriter(null);
} else {
return writer.getReader(applyAllDeletes);
}
}
private DirectoryReader doOpenFromWriter(IndexCommit commit) throws IOException {
if (commit != null) {
return doOpenFromCommit(commit);
}
if (writer.nrtIsCurrent(segmentInfos)) {
return null;
}
DirectoryReader reader = writer.getReader(applyAllDeletes);
// If in fact no changes took place, return null:
if (reader.getVersion() == segmentInfos.getVersion()) {
reader.decRef();
return null;
}
return reader;
}
private DirectoryReader doOpenNoWriter(IndexCommit commit) throws IOException {
if (commit == null) {
if (isCurrent()) {
return null;
}
} else {
if (directory != commit.getDirectory()) {
throw new IOException("the specified commit does not match the specified Directory");
}
if (segmentInfos != null && commit.getSegmentsFileName().equals(segmentInfos.getSegmentsFileName())) {
return null;
}
}
return doOpenFromCommit(commit);
}
private DirectoryReader doOpenFromCommit(IndexCommit commit) throws IOException {
return (DirectoryReader) new SegmentInfos.FindSegmentsFile(directory) {
@Override
protected Object doBody(String segmentFileName) throws IOException {
final SegmentInfos infos = new SegmentInfos();
infos.read(directory, segmentFileName);
return doOpenIfChanged(infos);
}
}.run(commit);
}
DirectoryReader doOpenIfChanged(SegmentInfos infos) throws IOException {
return StandardDirectoryReader.open(directory, infos, getSequentialSubReaders());
}
@Override
public long getVersion() {
ensureOpen();
return segmentInfos.getVersion();
}
@Override
public boolean isCurrent() throws IOException {
ensureOpen();
if (writer == null || writer.isClosed()) {
// Fully read the segments file: this ensures that it's
// completely written so that if
// IndexWriter.prepareCommit has been called (but not
// yet commit), then the reader will still see itself as
// current:
SegmentInfos sis = new SegmentInfos();
sis.read(directory);
// we loaded SegmentInfos from the directory
return sis.getVersion() == segmentInfos.getVersion();
} else {
return writer.nrtIsCurrent(segmentInfos);
}
}
@Override
protected void doClose() throws IOException {
Throwable firstExc = null;
for (final AtomicReader r : getSequentialSubReaders()) {
// try to close each reader, even if an exception is thrown
try {
r.decRef();
} catch (Throwable t) {
if (firstExc == null) {
firstExc = t;
}
}
}
if (writer != null) {
writer.decRefDeleter(segmentInfos);
// Since we just closed, writer may now be able to
// delete unused files:
writer.deletePendingFiles();
}
// throw the first exception
IOUtils.reThrow(firstExc);
}
@Override
public IndexCommit getIndexCommit() throws IOException {
ensureOpen();
return new ReaderCommit(segmentInfos, directory);
}
static final class ReaderCommit extends IndexCommit {
private String segmentsFileName;
Collection<String> files;
Directory dir;
long generation;
final Map<String,String> userData;
private final int segmentCount;
ReaderCommit(SegmentInfos infos, Directory dir) throws IOException {
segmentsFileName = infos.getSegmentsFileName();
this.dir = dir;
userData = infos.getUserData();
files = Collections.unmodifiableCollection(infos.files(dir, true));
generation = infos.getGeneration();
segmentCount = infos.size();
}
@Override
public String toString() {
return "DirectoryReader.ReaderCommit(" + segmentsFileName + ")";
}
@Override
public int getSegmentCount() {
return segmentCount;
}
@Override
public String getSegmentsFileName() {
return segmentsFileName;
}
@Override
public Collection<String> getFileNames() {
return files;
}
@Override
public Directory getDirectory() {
return dir;
}
@Override
public long getGeneration() {
return generation;
}
@Override
public boolean isDeleted() {
return false;
}
@Override
public Map<String,String> getUserData() {
return userData;
}
@Override
public void delete() {
throw new UnsupportedOperationException("This IndexCommit does not support deletions");
}
}
}