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 org.apache.lucene.store.Directory;
import org.apache.lucene.store.IndexOutput;
import org.apache.lucene.store.IndexInput;
import java.io.IOException;
final class SegmentInfo {
public String name; // unique name in dir
public int docCount; // number of docs in seg
public Directory dir; // where segment resides
private boolean preLockless; // true if this is a segments file written before
// lock-less commits (2.1)
private long delGen; // current generation of del file; -1 if there
// are no deletes; 0 if it's a pre-2.1 segment
// (and we must check filesystem); 1 or higher if
// there are deletes at generation N
private long[] normGen; // current generations of each field's norm file.
// If this array is null, we must check filesystem
// when preLockLess is true. Else,
// there are no separate norms
private byte isCompoundFile; // -1 if it is not; 1 if it is; 0 if it's
// pre-2.1 (ie, must check file system to see
// if <name>.cfs and <name>.nrm exist)
private boolean hasSingleNormFile; // true if this segment maintains norms in a single file;
// false otherwise
// this is currently false for segments populated by DocumentWriter
// and true for newly created merged segments (both
// compound and non compound).
public SegmentInfo(String name, int docCount, Directory dir) {
this.name = name;
this.docCount = docCount;
this.dir = dir;
delGen = -1;
isCompoundFile = 0;
preLockless = true;
hasSingleNormFile = false;
}
public SegmentInfo(String name, int docCount, Directory dir, boolean isCompoundFile, boolean hasSingleNormFile) {
this(name, docCount, dir);
this.isCompoundFile = (byte) (isCompoundFile ? 1 : -1);
this.hasSingleNormFile = hasSingleNormFile;
preLockless = false;
}
/**
* Copy everything from src SegmentInfo into our instance.
*/
void reset(SegmentInfo src) {
name = src.name;
docCount = src.docCount;
dir = src.dir;
preLockless = src.preLockless;
delGen = src.delGen;
if (src.normGen == null) {
normGen = null;
} else {
normGen = new long[src.normGen.length];
System.arraycopy(src.normGen, 0, normGen, 0, src.normGen.length);
}
isCompoundFile = src.isCompoundFile;
hasSingleNormFile = src.hasSingleNormFile;
}
/**
* Construct a new SegmentInfo instance by reading a
* previously saved SegmentInfo from input.
*
* @param dir directory to load from
* @param format format of the segments info file
* @param input input handle to read segment info from
*/
public SegmentInfo(Directory dir, int format, IndexInput input) throws IOException {
this.dir = dir;
name = input.readString();
docCount = input.readInt();
if (format <= SegmentInfos.FORMAT_LOCKLESS) {
delGen = input.readLong();
if (format <= SegmentInfos.FORMAT_SINGLE_NORM_FILE) {
hasSingleNormFile = (1 == input.readByte());
} else {
hasSingleNormFile = false;
}
int numNormGen = input.readInt();
if (numNormGen == -1) {
normGen = null;
} else {
normGen = new long[numNormGen];
for(int j=0;j<numNormGen;j++) {
normGen[j] = input.readLong();
}
}
isCompoundFile = input.readByte();
preLockless = isCompoundFile == 0;
} else {
delGen = 0;
normGen = null;
isCompoundFile = 0;
preLockless = true;
hasSingleNormFile = false;
}
}
void setNumFields(int numFields) {
if (normGen == null) {
// normGen is null if we loaded a pre-2.1 segment
// file, or, if this segments file hasn't had any
// norms set against it yet:
normGen = new long[numFields];
if (!preLockless) {
// This is a FORMAT_LOCKLESS segment, which means
// there are no norms:
for(int i=0;i<numFields;i++) {
normGen[i] = -1;
}
}
}
}
boolean hasDeletions()
throws IOException {
// Cases:
//
// delGen == -1: this means this segment was written
// by the LOCKLESS code and for certain does not have
// deletions yet
//
// delGen == 0: this means this segment was written by
// pre-LOCKLESS code which means we must check
// directory to see if .del file exists
//
// delGen > 0: this means this segment was written by
// the LOCKLESS code and for certain has
// deletions
//
if (delGen == -1) {
return false;
} else if (delGen > 0) {
return true;
} else {
return dir.fileExists(getDelFileName());
}
}
void advanceDelGen() {
// delGen 0 is reserved for pre-LOCKLESS format
if (delGen == -1) {
delGen = 1;
} else {
delGen++;
}
}
void clearDelGen() {
delGen = -1;
}
public Object clone () {
SegmentInfo si = new SegmentInfo(name, docCount, dir);
si.isCompoundFile = isCompoundFile;
si.delGen = delGen;
si.preLockless = preLockless;
si.hasSingleNormFile = hasSingleNormFile;
if (normGen != null) {
si.normGen = (long[]) normGen.clone();
}
return si;
}
String getDelFileName() {
if (delGen == -1) {
// In this case we know there is no deletion filename
// against this segment
return null;
} else {
// If delGen is 0, it's the pre-lockless-commit file format
return IndexFileNames.fileNameFromGeneration(name, ".del", delGen);
}
}
/**
* Returns true if this field for this segment has saved a separate norms file (_<segment>_N.sX).
*
* @param fieldNumber the field index to check
*/
boolean hasSeparateNorms(int fieldNumber)
throws IOException {
if ((normGen == null && preLockless) || (normGen != null && normGen[fieldNumber] == 0)) {
// Must fallback to directory file exists check:
String fileName = name + ".s" + fieldNumber;
return dir.fileExists(fileName);
} else if (normGen == null || normGen[fieldNumber] == -1) {
return false;
} else {
return true;
}
}
/**
* Returns true if any fields in this segment have separate norms.
*/
boolean hasSeparateNorms()
throws IOException {
if (normGen == null) {
if (!preLockless) {
// This means we were created w/ LOCKLESS code and no
// norms are written yet:
return false;
} else {
// This means this segment was saved with pre-LOCKLESS
// code. So we must fallback to the original
// directory list check:
String[] result = dir.list();
String pattern;
pattern = name + ".s";
int patternLength = pattern.length();
for(int i = 0; i < result.length; i++){
if(result[i].startsWith(pattern) && Character.isDigit(result[i].charAt(patternLength)))
return true;
}
return false;
}
} else {
// This means this segment was saved with LOCKLESS
// code so we first check whether any normGen's are >
// 0 (meaning they definitely have separate norms):
for(int i=0;i<normGen.length;i++) {
if (normGen[i] > 0) {
return true;
}
}
// Next we look for any == 0. These cases were
// pre-LOCKLESS and must be checked in directory:
for(int i=0;i<normGen.length;i++) {
if (normGen[i] == 0) {
if (hasSeparateNorms(i)) {
return true;
}
}
}
}
return false;
}
/**
* Increment the generation count for the norms file for
* this field.
*
* @param fieldIndex field whose norm file will be rewritten
*/
void advanceNormGen(int fieldIndex) {
if (normGen[fieldIndex] == -1) {
normGen[fieldIndex] = 1;
} else {
normGen[fieldIndex]++;
}
}
/**
* Get the file name for the norms file for this field.
*
* @param number field index
*/
String getNormFileName(int number) throws IOException {
String prefix;
long gen;
if (normGen == null) {
gen = 0;
} else {
gen = normGen[number];
}
if (hasSeparateNorms(number)) {
// case 1: separate norm
prefix = ".s";
return IndexFileNames.fileNameFromGeneration(name, prefix + number, gen);
}
if (hasSingleNormFile) {
// case 2: lockless (or nrm file exists) - single file for all norms
prefix = "." + IndexFileNames.NORMS_EXTENSION;
return IndexFileNames.fileNameFromGeneration(name, prefix, 0);
}
// case 3: norm file for each field
prefix = ".f";
return IndexFileNames.fileNameFromGeneration(name, prefix + number, 0);
}
/**
* Mark whether this segment is stored as a compound file.
*
* @param isCompoundFile true if this is a compound file;
* else, false
*/
void setUseCompoundFile(boolean isCompoundFile) {
if (isCompoundFile) {
this.isCompoundFile = 1;
} else {
this.isCompoundFile = -1;
}
}
/**
* Returns true if this segment is stored as a compound
* file; else, false.
*/
boolean getUseCompoundFile() throws IOException {
if (isCompoundFile == -1) {
return false;
} else if (isCompoundFile == 1) {
return true;
} else {
return dir.fileExists(name + ".cfs");
}
}
/**
* Save this segment's info.
*/
void write(IndexOutput output)
throws IOException {
output.writeString(name);
output.writeInt(docCount);
output.writeLong(delGen);
output.writeByte((byte) (hasSingleNormFile ? 1:0));
if (normGen == null) {
output.writeInt(-1);
} else {
output.writeInt(normGen.length);
for(int j = 0; j < normGen.length; j++) {
output.writeLong(normGen[j]);
}
}
output.writeByte(isCompoundFile);
}
}
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