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;
import java.util.List;
import java.util.ArrayList;
final class SegmentInfo {
static final int NO = -1; // e.g. no norms; no deletes;
static final int YES = 1; // e.g. have norms; have deletes;
static final int CHECK_DIR = 0; // e.g. must check dir to see if there are norms/deletions
static final int WITHOUT_GEN = 0; // a file name that has no GEN in it.
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; NO if there
// are no deletes; CHECK_DIR if it's a pre-2.1 segment
// (and we must check filesystem); YES or higher if
// there are deletes at generation N
private long[] normGen; // current generation of each field's norm file.
// If this array is null, for lockLess this means no
// separate norms. For preLockLess this means we must
// check filesystem. If this array is not null, its
// values mean: NO says this field has no separate
// norms; CHECK_DIR says it is a preLockLess segment and
// filesystem must be checked; >= YES says this field
// has separate norms with the specified generation
private byte isCompoundFile; // NO if it is not; YES if it is; CHECK_DIR 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).
private List files; // cached list of files that this segment uses
// in the Directory
public SegmentInfo(String name, int docCount, Directory dir) {
this.name = name;
this.docCount = docCount;
this.dir = dir;
delGen = NO;
isCompoundFile = CHECK_DIR;
preLockless = true;
hasSingleNormFile = false;
}
public SegmentInfo(String name, int docCount, Directory dir, boolean isCompoundFile, boolean hasSingleNormFile) {
this(name, docCount, dir);
this.isCompoundFile = (byte) (isCompoundFile ? YES : NO);
this.hasSingleNormFile = hasSingleNormFile;
preLockless = false;
}
/**
* Copy everything from src SegmentInfo into our instance.
*/
void reset(SegmentInfo src) {
files = null;
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
*/
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 == NO) {
normGen = null;
} else {
normGen = new long[numNormGen];
for(int j=0;j<numNormGen;j++) {
normGen[j] = input.readLong();
}
}
isCompoundFile = input.readByte();
preLockless = (isCompoundFile == CHECK_DIR);
} else {
delGen = CHECK_DIR;
normGen = null;
isCompoundFile = CHECK_DIR;
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) {
// Do nothing: thus leaving normGen[k]==CHECK_DIR (==0), so that later we know
// we have to check filesystem for norm files, because this is prelockless.
} else {
// This is a FORMAT_LOCKLESS segment, which means
// there are no separate norms:
for(int i=0;i<numFields;i++) {
normGen[i] = NO;
}
}
}
}
boolean hasDeletions()
throws IOException {
// Cases:
//
// delGen == NO: this means this segment was written
// by the LOCKLESS code and for certain does not have
// deletions yet
//
// delGen == CHECK_DIR: this means this segment was written by
// pre-LOCKLESS code which means we must check
// directory to see if .del file exists
//
// delGen >= YES: this means this segment was written by
// the LOCKLESS code and for certain has
// deletions
//
if (delGen == NO) {
return false;
} else if (delGen >= YES) {
return true;
} else {
return dir.fileExists(getDelFileName());
}
}
void advanceDelGen() {
// delGen 0 is reserved for pre-LOCKLESS format
if (delGen == NO) {
delGen = YES;
} else {
delGen++;
}
files = null;
}
void clearDelGen() {
delGen = NO;
files = null;
}
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 == NO) {
// In this case we know there is no deletion filename
// against this segment
return null;
} else {
// If delGen is CHECK_DIR, it's the pre-lockless-commit file format
return IndexFileNames.fileNameFromGeneration(name, "." + IndexFileNames.DELETES_EXTENSION, 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] == CHECK_DIR)) {
// Must fallback to directory file exists check:
String fileName = name + ".s" + fieldNumber;
return dir.fileExists(fileName);
} else if (normGen == null || normGen[fieldNumber] == NO) {
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();
if (result == null)
throw new IOException("cannot read directory " + dir + ": list() returned null");
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 >= 1
// (meaning they definitely have separate norms):
for(int i=0;i<normGen.length;i++) {
if (normGen[i] >= YES) {
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] == CHECK_DIR) {
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] == NO) {
normGen[fieldIndex] = YES;
} else {
normGen[fieldIndex]++;
}
files = null;
}
/**
* 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 = CHECK_DIR;
} 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, WITHOUT_GEN);
}
// case 3: norm file for each field
prefix = ".f";
return IndexFileNames.fileNameFromGeneration(name, prefix + number, WITHOUT_GEN);
}
/**
* 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 = YES;
} else {
this.isCompoundFile = NO;
}
files = null;
}
/**
* Returns true if this segment is stored as a compound
* file; else, false.
*/
boolean getUseCompoundFile() throws IOException {
if (isCompoundFile == NO) {
return false;
} else if (isCompoundFile == YES) {
return true;
} else {
return dir.fileExists(name + "." + IndexFileNames.COMPOUND_FILE_EXTENSION);
}
}
/**
* 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(NO);
} else {
output.writeInt(normGen.length);
for(int j = 0; j < normGen.length; j++) {
output.writeLong(normGen[j]);
}
}
output.writeByte(isCompoundFile);
}
/*
* Return all files referenced by this SegmentInfo. The
* returns List is a locally cached List so you should not
* modify it.
*/
public List files() throws IOException {
if (files != null) {
// Already cached:
return files;
}
files = new ArrayList();
boolean useCompoundFile = getUseCompoundFile();
if (useCompoundFile) {
files.add(name + "." + IndexFileNames.COMPOUND_FILE_EXTENSION);
} else {
for (int i = 0; i < IndexFileNames.INDEX_EXTENSIONS_IN_COMPOUND_FILE.length; i++) {
String ext = IndexFileNames.INDEX_EXTENSIONS_IN_COMPOUND_FILE[i];
String fileName = name + "." + ext;
if (dir.fileExists(fileName)) {
files.add(fileName);
}
}
}
String delFileName = IndexFileNames.fileNameFromGeneration(name, "." + IndexFileNames.DELETES_EXTENSION, delGen);
if (delFileName != null && (delGen >= YES || dir.fileExists(delFileName))) {
files.add(delFileName);
}
// Careful logic for norms files
if (normGen != null) {
for(int i=0;i<normGen.length;i++) {
long gen = normGen[i];
if (gen >= YES) {
// Definitely a separate norm file, with generation:
files.add(IndexFileNames.fileNameFromGeneration(name, "." + IndexFileNames.SEPARATE_NORMS_EXTENSION + i, gen));
} else if (NO == gen) {
// No separate norms but maybe plain norms
// in the non compound file case:
if (!hasSingleNormFile && !useCompoundFile) {
String fileName = name + "." + IndexFileNames.PLAIN_NORMS_EXTENSION + i;
if (dir.fileExists(fileName)) {
files.add(fileName);
}
}
} else if (CHECK_DIR == gen) {
// Pre-2.1: we have to check file existence
String fileName = null;
if (useCompoundFile) {
fileName = name + "." + IndexFileNames.SEPARATE_NORMS_EXTENSION + i;
} else if (!hasSingleNormFile) {
fileName = name + "." + IndexFileNames.PLAIN_NORMS_EXTENSION + i;
}
if (fileName != null && dir.fileExists(fileName)) {
files.add(fileName);
}
}
}
} else if (preLockless || (!hasSingleNormFile && !useCompoundFile)) {
// Pre-2.1: we have to scan the dir to find all
// matching _X.sN/_X.fN files for our segment:
String prefix;
if (useCompoundFile)
prefix = name + "." + IndexFileNames.SEPARATE_NORMS_EXTENSION;
else
prefix = name + "." + IndexFileNames.PLAIN_NORMS_EXTENSION;
int prefixLength = prefix.length();
String[] allFiles = dir.list();
if (allFiles == null)
throw new IOException("cannot read directory " + dir + ": list() returned null");
for(int i=0;i<allFiles.length;i++) {
String fileName = allFiles[i];
if (fileName.length() > prefixLength && Character.isDigit(fileName.charAt(prefixLength)) && fileName.startsWith(prefix)) {
files.add(fileName);
}
}
}
return files;
}
}
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