package org.apache.lucene.codecs.blocktree;
/*
* 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.io.PrintStream;
import java.util.Collections;
import java.util.Iterator;
import java.util.TreeMap;
import org.apache.lucene.codecs.BlockTermState;
import org.apache.lucene.codecs.CodecUtil;
import org.apache.lucene.codecs.FieldsProducer;
import org.apache.lucene.codecs.PostingsReaderBase;
import org.apache.lucene.index.CorruptIndexException;
import org.apache.lucene.index.DocsAndPositionsEnum;
import org.apache.lucene.index.DocsEnum;
import org.apache.lucene.index.FieldInfo.IndexOptions;
import org.apache.lucene.index.FieldInfo;
import org.apache.lucene.index.FieldInfos;
import org.apache.lucene.index.IndexFileNames;
import org.apache.lucene.index.SegmentInfo;
import org.apache.lucene.index.TermState;
import org.apache.lucene.index.Terms;
import org.apache.lucene.index.TermsEnum;
import org.apache.lucene.store.ByteArrayDataInput;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.IOContext;
import org.apache.lucene.store.IndexInput;
import org.apache.lucene.util.ArrayUtil;
import org.apache.lucene.util.Bits;
import org.apache.lucene.util.BytesRef;
import org.apache.lucene.util.IOUtils;
import org.apache.lucene.util.RamUsageEstimator;
import org.apache.lucene.util.StringHelper;
import org.apache.lucene.util.automaton.CompiledAutomaton;
import org.apache.lucene.util.automaton.RunAutomaton;
import org.apache.lucene.util.automaton.Transition;
import org.apache.lucene.util.fst.ByteSequenceOutputs;
import org.apache.lucene.util.fst.FST;
import org.apache.lucene.util.fst.Outputs;
import org.apache.lucene.util.fst.Util;
/** A block-based terms index and dictionary that assigns
* terms to variable length blocks according to how they
* share prefixes. The terms index is a prefix trie
* whose leaves are term blocks. The advantage of this
* approach is that seekExact is often able to
* determine a term cannot exist without doing any IO, and
* intersection with Automata is very fast. Note that this
* terms dictionary has it's own fixed terms index (ie, it
* does not support a pluggable terms index
* implementation).
*
* <p><b>NOTE</b>: this terms dictionary does not support
* index divisor when opening an IndexReader. Instead, you
* can change the min/maxItemsPerBlock during indexing.</p>
*
* <p>The data structure used by this implementation is very
* similar to a burst trie
* (http://citeseer.ist.psu.edu/viewdoc/summary?doi=10.1.1.18.3499),
* but with added logic to break up too-large blocks of all
* terms sharing a given prefix into smaller ones.</p>
*
* <p>Use {@link org.apache.lucene.index.CheckIndex} with the <code>-verbose</code>
* option to see summary statistics on the blocks in the
* dictionary.
*
* See {@link BlockTreeTermsWriter}.
*
* @lucene.experimental
*/
public class BlockTreeTermsReader extends FieldsProducer {
private static long BASE_RAM_BYTES_USED = RamUsageEstimator.shallowSizeOfInstance(BlockTreeTermsReader.class);
// Open input to the main terms dict file (_X.tib)
final IndexInput in;
//private static final boolean DEBUG = BlockTreeTermsWriter.DEBUG;
// Reads the terms dict entries, to gather state to
// produce DocsEnum on demand
final PostingsReaderBase postingsReader;
private final TreeMap<String,FieldReader> fields = new TreeMap<>();
/** File offset where the directory starts in the terms file. */
private long dirOffset;
/** File offset where the directory starts in the index file. */
private long indexDirOffset;
final String segment;
private final int version;
/** Sole constructor. */
public BlockTreeTermsReader(Directory dir, FieldInfos fieldInfos, SegmentInfo info,
PostingsReaderBase postingsReader, IOContext ioContext,
String segmentSuffix, int indexDivisor)
throws IOException {
this.postingsReader = postingsReader;
this.segment = info.name;
in = dir.openInput(IndexFileNames.segmentFileName(segment, segmentSuffix, BlockTreeTermsWriter.TERMS_EXTENSION),
ioContext);
boolean success = false;
IndexInput indexIn = null;
try {
version = readHeader(in);
if (indexDivisor != -1) {
indexIn = dir.openInput(IndexFileNames.segmentFileName(segment, segmentSuffix, BlockTreeTermsWriter.TERMS_INDEX_EXTENSION),
ioContext);
int indexVersion = readIndexHeader(indexIn);
if (indexVersion != version) {
throw new CorruptIndexException("mixmatched version files: " + in + "=" + version + "," + indexIn + "=" + indexVersion);
}
}
// verify
if (indexIn != null && version >= BlockTreeTermsWriter.VERSION_CHECKSUM) {
CodecUtil.checksumEntireFile(indexIn);
}
// Have PostingsReader init itself
postingsReader.init(in);
// Read per-field details
seekDir(in, dirOffset);
if (indexDivisor != -1) {
seekDir(indexIn, indexDirOffset);
}
final int numFields = in.readVInt();
if (numFields < 0) {
throw new CorruptIndexException("invalid numFields: " + numFields + " (resource=" + in + ")");
}
for(int i=0;i<numFields;i++) {
final int field = in.readVInt();
final long numTerms = in.readVLong();
assert numTerms >= 0;
final int numBytes = in.readVInt();
final BytesRef rootCode = new BytesRef(new byte[numBytes]);
in.readBytes(rootCode.bytes, 0, numBytes);
rootCode.length = numBytes;
final FieldInfo fieldInfo = fieldInfos.fieldInfo(field);
assert fieldInfo != null: "field=" + field;
final long sumTotalTermFreq = fieldInfo.getIndexOptions() == IndexOptions.DOCS_ONLY ? -1 : in.readVLong();
final long sumDocFreq = in.readVLong();
final int docCount = in.readVInt();
final int longsSize = version >= BlockTreeTermsWriter.VERSION_META_ARRAY ? in.readVInt() : 0;
BytesRef minTerm, maxTerm;
if (version >= BlockTreeTermsWriter.VERSION_MIN_MAX_TERMS) {
minTerm = readBytesRef(in);
maxTerm = readBytesRef(in);
} else {
minTerm = maxTerm = null;
}
if (docCount < 0 || docCount > info.getDocCount()) { // #docs with field must be <= #docs
throw new CorruptIndexException("invalid docCount: " + docCount + " maxDoc: " + info.getDocCount() + " (resource=" + in + ")");
}
if (sumDocFreq < docCount) { // #postings must be >= #docs with field
throw new CorruptIndexException("invalid sumDocFreq: " + sumDocFreq + " docCount: " + docCount + " (resource=" + in + ")");
}
if (sumTotalTermFreq != -1 && sumTotalTermFreq < sumDocFreq) { // #positions must be >= #postings
throw new CorruptIndexException("invalid sumTotalTermFreq: " + sumTotalTermFreq + " sumDocFreq: " + sumDocFreq + " (resource=" + in + ")");
}
final long indexStartFP = indexDivisor != -1 ? indexIn.readVLong() : 0;
FieldReader previous = fields.put(fieldInfo.name,
new FieldReader(this, fieldInfo, numTerms, rootCode, sumTotalTermFreq, sumDocFreq, docCount,
indexStartFP, longsSize, indexIn, minTerm, maxTerm));
if (previous != null) {
throw new CorruptIndexException("duplicate field: " + fieldInfo.name + " (resource=" + in + ")");
}
}
if (indexDivisor != -1) {
indexIn.close();
}
success = true;
} finally {
if (!success) {
// this.close() will close in:
IOUtils.closeWhileHandlingException(indexIn, this);
}
}
}
private static BytesRef readBytesRef(IndexInput in) throws IOException {
BytesRef bytes = new BytesRef();
bytes.length = in.readVInt();
bytes.bytes = new byte[bytes.length];
in.readBytes(bytes.bytes, 0, bytes.length);
return bytes;
}
/** Reads terms file header. */
protected int readHeader(IndexInput input) throws IOException {
int version = CodecUtil.checkHeader(input, BlockTreeTermsWriter.TERMS_CODEC_NAME,
BlockTreeTermsWriter.VERSION_START,
BlockTreeTermsWriter.VERSION_CURRENT);
if (version < BlockTreeTermsWriter.VERSION_APPEND_ONLY) {
dirOffset = input.readLong();
}
return version;
}
/** Reads index file header. */
protected int readIndexHeader(IndexInput input) throws IOException {
int version = CodecUtil.checkHeader(input, BlockTreeTermsWriter.TERMS_INDEX_CODEC_NAME,
BlockTreeTermsWriter.VERSION_START,
BlockTreeTermsWriter.VERSION_CURRENT);
if (version < BlockTreeTermsWriter.VERSION_APPEND_ONLY) {
indexDirOffset = input.readLong();
}
return version;
}
/** Seek {@code input} to the directory offset. */
protected void seekDir(IndexInput input, long dirOffset)
throws IOException {
if (version >= BlockTreeTermsWriter.VERSION_CHECKSUM) {
input.seek(input.length() - CodecUtil.footerLength() - 8);
dirOffset = input.readLong();
} else if (version >= BlockTreeTermsWriter.VERSION_APPEND_ONLY) {
input.seek(input.length() - 8);
dirOffset = input.readLong();
}
input.seek(dirOffset);
}
// for debugging
// private static String toHex(int v) {
// return "0x" + Integer.toHexString(v);
// }
@Override
public void close() throws IOException {
try {
IOUtils.close(in, postingsReader);
} finally {
// Clear so refs to terms index is GCable even if
// app hangs onto us:
fields.clear();
}
}
@Override
public Iterator<String> iterator() {
return Collections.unmodifiableSet(fields.keySet()).iterator();
}
@Override
public Terms terms(String field) throws IOException {
assert field != null;
return fields.get(field);
}
@Override
public int size() {
return fields.size();
}
// for debugging
String brToString(BytesRef b) {
if (b == null) {
return "null";
} else {
try {
return b.utf8ToString() + " " + b;
} catch (Throwable t) {
// If BytesRef isn't actually UTF8, or it's eg a
// prefix of UTF8 that ends mid-unicode-char, we
// fallback to hex:
return b.toString();
}
}
}
@Override
public long ramBytesUsed() {
long sizeInByes = BASE_RAM_BYTES_USED
+ ((postingsReader!=null) ? postingsReader.ramBytesUsed() : 0)
+ fields.size() * 2L * RamUsageEstimator.NUM_BYTES_OBJECT_REF;
for(FieldReader reader : fields.values()) {
sizeInByes += reader.ramBytesUsed();
}
return sizeInByes;
}
@Override
public void checkIntegrity() throws IOException {
if (version >= BlockTreeTermsWriter.VERSION_CHECKSUM) {
// term dictionary
CodecUtil.checksumEntireFile(in);
// postings
postingsReader.checkIntegrity();
}
}
}