| 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.util.Collections; |
| import java.util.Iterator; |
| import java.util.TreeMap; |
| |
| 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.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.Terms; |
| import org.apache.lucene.store.Directory; |
| import org.apache.lucene.store.IOContext; |
| import org.apache.lucene.store.IndexInput; |
| import org.apache.lucene.util.BytesRef; |
| import org.apache.lucene.util.IOUtils; |
| import org.apache.lucene.util.RamUsageEstimator; |
| |
| /** 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); |
| |
| |
| // NOTE: data file is too costly to verify checksum against all the bytes on open, |
| // but for now we at least verify proper structure of the checksum footer: which looks |
| // for FOOTER_MAGIC + algorithmID. This is cheap and can detect some forms of corruption |
| // such as file truncation. |
| if (version >= BlockTreeTermsWriter.VERSION_CHECKSUM) { |
| CodecUtil.retrieveChecksum(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(); |
| if (numTerms <= 0) { |
| throw new CorruptIndexException("Illegal numTerms for field number: " + field + " (resource=" + in + ")"); |
| } |
| final int numBytes = in.readVInt(); |
| if (numBytes < 0) { |
| throw new CorruptIndexException("invalid rootCode for field number: " + field + ", numBytes=" + numBytes + " (resource=" + in + ")"); |
| } |
| final BytesRef rootCode = new BytesRef(new byte[numBytes]); |
| in.readBytes(rootCode.bytes, 0, numBytes); |
| rootCode.length = numBytes; |
| final FieldInfo fieldInfo = fieldInfos.fieldInfo(field); |
| if (fieldInfo == null) { |
| throw new CorruptIndexException("invalid field number: " + field + ", resource=" + in + ")"); |
| } |
| 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; |
| if (longsSize < 0) { |
| throw new CorruptIndexException("invalid longsSize for field: " + fieldInfo.name + ", longsSize=" + longsSize + " (resource=" + in + ")"); |
| } |
| 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(); |
| } |
| } |
| } |
