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.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import org.apache.lucene.codecs.Codec;
import org.apache.lucene.codecs.DocValuesFormat;
import org.apache.lucene.codecs.DocValuesProducer;
import org.apache.lucene.codecs.StoredFieldsReader;
import org.apache.lucene.codecs.TermVectorsReader;
import org.apache.lucene.index.FieldInfo.DocValuesType;
import org.apache.lucene.search.FieldCache;
import org.apache.lucene.store.CompoundFileDirectory;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.IOContext;
import org.apache.lucene.util.Bits;
import org.apache.lucene.util.CloseableThreadLocal;
/**
* IndexReader implementation over a single segment.
* <p>
* Instances pointing to the same segment (but with different deletes, etc)
* may share the same core data.
* @lucene.experimental
*/
public final class SegmentReader extends AtomicReader {
private final SegmentCommitInfo si;
private final Bits liveDocs;
// Normally set to si.docCount - si.delDocCount, unless we
// were created as an NRT reader from IW, in which case IW
// tells us the docCount:
private final int numDocs;
final SegmentCoreReaders core;
final SegmentDocValues segDocValues;
final CloseableThreadLocal<Map<String,Object>> docValuesLocal = new CloseableThreadLocal<Map<String,Object>>() {
@Override
protected Map<String,Object> initialValue() {
return new HashMap<>();
}
};
final CloseableThreadLocal<Map<String,Bits>> docsWithFieldLocal = new CloseableThreadLocal<Map<String,Bits>>() {
@Override
protected Map<String,Bits> initialValue() {
return new HashMap<>();
}
};
final Map<String,DocValuesProducer> dvProducers = new HashMap<>();
final FieldInfos fieldInfos;
private final List<Long> dvGens = new ArrayList<>();
/**
* Constructs a new SegmentReader with a new core.
* @throws CorruptIndexException if the index is corrupt
* @throws IOException if there is a low-level IO error
*/
// TODO: why is this public?
public SegmentReader(SegmentCommitInfo si, IOContext context) throws IOException {
this.si = si;
// TODO if the segment uses CFS, we may open the CFS file twice: once for
// reading the FieldInfos (if they are not gen'd) and second time by
// SegmentCoreReaders. We can open the CFS here and pass to SCR, but then it
// results in less readable code (resource not closed where it was opened).
// Best if we could somehow read FieldInfos in SCR but not keep it there, but
// constructors don't allow returning two things...
fieldInfos = readFieldInfos(si);
core = new SegmentCoreReaders(this, si.info.dir, si, context);
segDocValues = new SegmentDocValues();
boolean success = false;
final Codec codec = si.info.getCodec();
try {
if (si.hasDeletions()) {
// NOTE: the bitvector is stored using the regular directory, not cfs
liveDocs = codec.liveDocsFormat().readLiveDocs(directory(), si, IOContext.READONCE);
} else {
assert si.getDelCount() == 0;
liveDocs = null;
}
numDocs = si.info.getDocCount() - si.getDelCount();
if (fieldInfos.hasDocValues()) {
initDocValuesProducers(codec);
}
success = true;
} finally {
// With lock-less commits, it's entirely possible (and
// fine) to hit a FileNotFound exception above. In
// this case, we want to explicitly close any subset
// of things that were opened so that we don't have to
// wait for a GC to do so.
if (!success) {
doClose();
}
}
}
/** Create new SegmentReader sharing core from a previous
* SegmentReader and loading new live docs from a new
* deletes file. Used by openIfChanged. */
SegmentReader(SegmentCommitInfo si, SegmentReader sr) throws IOException {
this(si, sr,
si.info.getCodec().liveDocsFormat().readLiveDocs(si.info.dir, si, IOContext.READONCE),
si.info.getDocCount() - si.getDelCount());
}
/** Create new SegmentReader sharing core from a previous
* SegmentReader and using the provided in-memory
* liveDocs. Used by IndexWriter to provide a new NRT
* reader */
SegmentReader(SegmentCommitInfo si, SegmentReader sr, Bits liveDocs, int numDocs) throws IOException {
this.si = si;
this.liveDocs = liveDocs;
this.numDocs = numDocs;
this.core = sr.core;
core.incRef();
this.segDocValues = sr.segDocValues;
// System.out.println("[" + Thread.currentThread().getName() + "] SR.init: sharing reader: " + sr + " for gens=" + sr.genDVProducers.keySet());
// increment refCount of DocValuesProducers that are used by this reader
boolean success = false;
try {
final Codec codec = si.info.getCodec();
if (si.getFieldInfosGen() == -1) {
fieldInfos = sr.fieldInfos;
} else {
fieldInfos = readFieldInfos(si);
}
if (fieldInfos.hasDocValues()) {
initDocValuesProducers(codec);
}
success = true;
} finally {
if (!success) {
doClose();
}
}
}
// initialize the per-field DocValuesProducer
private void initDocValuesProducers(Codec codec) throws IOException {
final Directory dir = core.cfsReader != null ? core.cfsReader : si.info.dir;
final DocValuesFormat dvFormat = codec.docValuesFormat();
final Map<Long,List<FieldInfo>> genInfos = getGenInfos();
// System.out.println("[" + Thread.currentThread().getName() + "] SR.initDocValuesProducers: segInfo=" + si + "; gens=" + genInfos.keySet());
for (Entry<Long,List<FieldInfo>> e : genInfos.entrySet()) {
Long gen = e.getKey();
List<FieldInfo> infos = e.getValue();
DocValuesProducer dvp = segDocValues.getDocValuesProducer(gen, si, IOContext.READ, dir, dvFormat, infos);
for (FieldInfo fi : infos) {
dvProducers.put(fi.name, dvp);
}
}
dvGens.addAll(genInfos.keySet());
}
/**
* Reads the most recent {@link FieldInfos} of the given segment info.
*
* @lucene.internal
*/
static FieldInfos readFieldInfos(SegmentCommitInfo info) throws IOException {
final Directory dir;
final boolean closeDir;
if (info.getFieldInfosGen() == -1 && info.info.getUseCompoundFile()) {
// no fieldInfos gen and segment uses a compound file
dir = new CompoundFileDirectory(info.info.dir,
IndexFileNames.segmentFileName(info.info.name, "", IndexFileNames.COMPOUND_FILE_EXTENSION),
IOContext.READONCE,
false);
closeDir = true;
} else {
// gen'd FIS are read outside CFS, or the segment doesn't use a compound file
dir = info.info.dir;
closeDir = false;
}
try {
final String segmentSuffix = info.getFieldInfosGen() == -1 ? "" : Long.toString(info.getFieldInfosGen(), Character.MAX_RADIX);
return info.info.getCodec().fieldInfosFormat().getFieldInfosReader().read(dir, info.info.name, segmentSuffix, IOContext.READONCE);
} finally {
if (closeDir) {
dir.close();
}
}
}
// returns a gen->List<FieldInfo> mapping. Fields without DV updates have gen=-1
private Map<Long,List<FieldInfo>> getGenInfos() {
final Map<Long,List<FieldInfo>> genInfos = new HashMap<>();
for (FieldInfo fi : fieldInfos) {
if (fi.getDocValuesType() == null) {
continue;
}
long gen = fi.getDocValuesGen();
List<FieldInfo> infos = genInfos.get(gen);
if (infos == null) {
infos = new ArrayList<>();
genInfos.put(gen, infos);
}
infos.add(fi);
}
return genInfos;
}
@Override
public Bits getLiveDocs() {
ensureOpen();
return liveDocs;
}
@Override
protected void doClose() throws IOException {
//System.out.println("SR.close seg=" + si);
try {
core.decRef();
} finally {
dvProducers.clear();
docValuesLocal.close();
docsWithFieldLocal.close();
segDocValues.decRef(dvGens);
}
}
@Override
public FieldInfos getFieldInfos() {
ensureOpen();
return fieldInfos;
}
/** Expert: retrieve thread-private {@link
* StoredFieldsReader}
* @lucene.internal */
public StoredFieldsReader getFieldsReader() {
ensureOpen();
return core.fieldsReaderLocal.get();
}
@Override
public void document(int docID, StoredFieldVisitor visitor) throws IOException {
checkBounds(docID);
getFieldsReader().visitDocument(docID, visitor);
}
@Override
public Fields fields() {
ensureOpen();
return core.fields;
}
@Override
public int numDocs() {
// Don't call ensureOpen() here (it could affect performance)
return numDocs;
}
@Override
public int maxDoc() {
// Don't call ensureOpen() here (it could affect performance)
return si.info.getDocCount();
}
/** Expert: retrieve thread-private {@link
* TermVectorsReader}
* @lucene.internal */
public TermVectorsReader getTermVectorsReader() {
ensureOpen();
return core.termVectorsLocal.get();
}
@Override
public Fields getTermVectors(int docID) throws IOException {
TermVectorsReader termVectorsReader = getTermVectorsReader();
if (termVectorsReader == null) {
return null;
}
checkBounds(docID);
return termVectorsReader.get(docID);
}
private void checkBounds(int docID) {
if (docID < 0 || docID >= maxDoc()) {
throw new IndexOutOfBoundsException("docID must be >= 0 and < maxDoc=" + maxDoc() + " (got docID=" + docID + ")");
}
}
@Override
public String toString() {
// SegmentInfo.toString takes dir and number of
// *pending* deletions; so we reverse compute that here:
return si.toString(si.info.dir, si.info.getDocCount() - numDocs - si.getDelCount());
}
/**
* Return the name of the segment this reader is reading.
*/
public String getSegmentName() {
return si.info.name;
}
/**
* Return the SegmentInfoPerCommit of the segment this reader is reading.
*/
public SegmentCommitInfo getSegmentInfo() {
return si;
}
/** Returns the directory this index resides in. */
public Directory directory() {
// Don't ensureOpen here -- in certain cases, when a
// cloned/reopened reader needs to commit, it may call
// this method on the closed original reader
return si.info.dir;
}
// This is necessary so that cloned SegmentReaders (which
// share the underlying postings data) will map to the
// same entry in the FieldCache. See LUCENE-1579.
@Override
public Object getCoreCacheKey() {
// NOTE: if this ever changes, be sure to fix
// SegmentCoreReader.notifyCoreClosedListeners to match!
// Today it passes "this" as its coreCacheKey:
return core;
}
@Override
public Object getCombinedCoreAndDeletesKey() {
return this;
}
// returns the FieldInfo that corresponds to the given field and type, or
// null if the field does not exist, or not indexed as the requested
// DovDocValuesType.
private FieldInfo getDVField(String field, DocValuesType type) {
FieldInfo fi = fieldInfos.fieldInfo(field);
if (fi == null) {
// Field does not exist
return null;
}
if (fi.getDocValuesType() == null) {
// Field was not indexed with doc values
return null;
}
if (fi.getDocValuesType() != type) {
// Field DocValues are different than requested type
return null;
}
return fi;
}
@Override
public NumericDocValues getNumericDocValues(String field) throws IOException {
ensureOpen();
FieldInfo fi = getDVField(field, DocValuesType.NUMERIC);
if (fi == null) {
return null;
}
DocValuesProducer dvProducer = dvProducers.get(field);
assert dvProducer != null;
Map<String,Object> dvFields = docValuesLocal.get();
NumericDocValues dvs = (NumericDocValues) dvFields.get(field);
if (dvs == null) {
dvs = dvProducer.getNumeric(fi);
dvFields.put(field, dvs);
}
return dvs;
}
@Override
public Bits getDocsWithField(String field) throws IOException {
ensureOpen();
FieldInfo fi = fieldInfos.fieldInfo(field);
if (fi == null) {
// Field does not exist
return null;
}
if (fi.getDocValuesType() == null) {
// Field was not indexed with doc values
return null;
}
DocValuesProducer dvProducer = dvProducers.get(field);
assert dvProducer != null;
Map<String,Bits> dvFields = docsWithFieldLocal.get();
Bits dvs = dvFields.get(field);
if (dvs == null) {
dvs = dvProducer.getDocsWithField(fi);
dvFields.put(field, dvs);
}
return dvs;
}
@Override
public BinaryDocValues getBinaryDocValues(String field) throws IOException {
ensureOpen();
FieldInfo fi = getDVField(field, DocValuesType.BINARY);
if (fi == null) {
return null;
}
DocValuesProducer dvProducer = dvProducers.get(field);
assert dvProducer != null;
Map<String,Object> dvFields = docValuesLocal.get();
BinaryDocValues dvs = (BinaryDocValues) dvFields.get(field);
if (dvs == null) {
dvs = dvProducer.getBinary(fi);
dvFields.put(field, dvs);
}
return dvs;
}
@Override
public SortedDocValues getSortedDocValues(String field) throws IOException {
ensureOpen();
FieldInfo fi = getDVField(field, DocValuesType.SORTED);
if (fi == null) {
return null;
}
DocValuesProducer dvProducer = dvProducers.get(field);
assert dvProducer != null;
Map<String,Object> dvFields = docValuesLocal.get();
SortedDocValues dvs = (SortedDocValues) dvFields.get(field);
if (dvs == null) {
dvs = dvProducer.getSorted(fi);
dvFields.put(field, dvs);
}
return dvs;
}
@Override
public SortedSetDocValues getSortedSetDocValues(String field) throws IOException {
ensureOpen();
FieldInfo fi = getDVField(field, DocValuesType.SORTED_SET);
if (fi == null) {
return null;
}
DocValuesProducer dvProducer = dvProducers.get(field);
assert dvProducer != null;
Map<String,Object> dvFields = docValuesLocal.get();
SortedSetDocValues dvs = (SortedSetDocValues) dvFields.get(field);
if (dvs == null) {
dvs = dvProducer.getSortedSet(fi);
dvFields.put(field, dvs);
}
return dvs;
}
@Override
public NumericDocValues getNormValues(String field) throws IOException {
ensureOpen();
FieldInfo fi = fieldInfos.fieldInfo(field);
if (fi == null || !fi.hasNorms()) {
// Field does not exist or does not index norms
return null;
}
return core.getNormValues(fi);
}
/**
* Called when the shared core for this SegmentReader
* is closed.
* <p>
* This listener is called only once all SegmentReaders
* sharing the same core are closed. At this point it
* is safe for apps to evict this reader from any caches
* keyed on {@link #getCoreCacheKey}. This is the same
* interface that {@link FieldCache} uses, internally,
* to evict entries.</p>
*
* @lucene.experimental
*/
public static interface CoreClosedListener {
/** Invoked when the shared core of the original {@code
* SegmentReader} has closed. */
public void onClose(Object ownerCoreCacheKey);
}
/** Expert: adds a CoreClosedListener to this reader's shared core */
public void addCoreClosedListener(CoreClosedListener listener) {
ensureOpen();
core.addCoreClosedListener(listener);
}
/** Expert: removes a CoreClosedListener from this reader's shared core */
public void removeCoreClosedListener(CoreClosedListener listener) {
ensureOpen();
core.removeCoreClosedListener(listener);
}
/** Returns approximate RAM Bytes used */
public long ramBytesUsed() {
ensureOpen();
long ramBytesUsed = 0;
if (segDocValues != null) {
ramBytesUsed += segDocValues.ramBytesUsed();
}
if (core != null) {
ramBytesUsed += core.ramBytesUsed();
}
return ramBytesUsed;
}
}