LUCENE-4055: use codec header instead

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/lucene4055@1342219 13f79535-47bb-0310-9956-ffa450edef68

lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40FieldInfosFormat.java

@@ -18,25 +18,25 @@ package org.apache.lucene.codecs.lucene40;
  */
 
 import java.io.IOException;
-import java.util.Set;
 
 import org.apache.lucene.codecs.FieldInfosFormat;
 import org.apache.lucene.codecs.FieldInfosReader;
 import org.apache.lucene.codecs.FieldInfosWriter;
 import org.apache.lucene.index.DocValues; // javadoc
 import org.apache.lucene.index.DocValues.Type; // javadoc
-import org.apache.lucene.index.SegmentInfo;
 import org.apache.lucene.store.DataOutput; // javadoc
+import org.apache.lucene.util.CodecUtil; // javadoc
 
 /**
  * Lucene 4.0 Field Infos format.
  * <p>
  * <p>Field names are stored in the field info file, with suffix <tt>.fnm</tt>.</p>
- * <p>FieldInfos (.fnm) --&gt; FNMVersion,FieldsCount, &lt;FieldName,FieldNumber,
+ * <p>FieldInfos (.fnm) --&gt; Header,FieldsCount, &lt;FieldName,FieldNumber,
  * FieldBits,DocValuesBits,Attributes&gt; <sup>FieldsCount</sup></p>
  * <p>Data types:
  * <ul>
- *   <li>FNMVersion, FieldsCount --&gt; {@link DataOutput#writeVInt VInt}</li>
+ *   <li>Header --&gt; {@link CodecUtil#checkHeader CodecHeader}</li>
+ *   <li>FieldsCount --&gt; {@link DataOutput#writeVInt VInt}</li>
  *   <li>FieldName --&gt; {@link DataOutput#writeString String}</li>
  *   <li>FieldBits, DocValuesBits --&gt; {@link DataOutput#writeByte Byte}</li>
  *   <li>FieldNumber --&gt; {@link DataOutput#writeInt VInt}</li>
@@ -45,7 +45,6 @@ import org.apache.lucene.store.DataOutput; // javadoc
  * </p>
  * Field Descriptions:
  * <ul>
- *   <li>FNMVersion is <code>Lucene40FieldInfosWriter.FORMAT_CURRENT</code>.</li>
  *   <li>FieldsCount: the number of fields in this file.</li>
  *   <li>FieldName: name of the field as a UTF-8 String.</li>
  *   <li>FieldNumber: the field's number. Note that unlike previous versions of

lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40FieldInfosReader.java

@@ -18,6 +18,7 @@ import org.apache.lucene.index.DocValues;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.IOContext;
 import org.apache.lucene.store.IndexInput;
+import org.apache.lucene.util.CodecUtil;
 
 /**
  * Licensed to the Apache Software Foundation (ASF) under one or more
@@ -44,22 +45,15 @@ import org.apache.lucene.store.IndexInput;
  */
 public class Lucene40FieldInfosReader extends FieldInfosReader {
 
-  static final int FORMAT_MINIMUM = Lucene40FieldInfosWriter.FORMAT_START;
-
   @Override
   public FieldInfos read(Directory directory, String segmentName, IOContext iocontext) throws IOException {
     final String fileName = IndexFileNames.segmentFileName(segmentName, "", Lucene40FieldInfosWriter.FIELD_INFOS_EXTENSION);
     IndexInput input = directory.openInput(fileName, iocontext);
     
     try {
-      final int format = input.readVInt();
-
-      if (format > FORMAT_MINIMUM) {
-        throw new IndexFormatTooOldException(input, format, FORMAT_MINIMUM, Lucene40FieldInfosWriter.FORMAT_CURRENT);
-      }
-      if (format < Lucene40FieldInfosWriter.FORMAT_CURRENT) {
-        throw new IndexFormatTooNewException(input, format, FORMAT_MINIMUM, Lucene40FieldInfosWriter.FORMAT_CURRENT);
-      }
+      CodecUtil.checkHeader(input, Lucene40FieldInfosWriter.CODEC_NAME, 
+                                   Lucene40FieldInfosWriter.FORMAT_START, 
+                                   Lucene40FieldInfosWriter.FORMAT_CURRENT);
 
       final int size = input.readVInt(); //read in the size
       FieldInfo infos[] = new FieldInfo[size];

lucene/core/src/java/org/apache/lucene/codecs/lucene40/Lucene40FieldInfosWriter.java

@@ -27,6 +27,7 @@ import org.apache.lucene.index.FieldInfo.IndexOptions;
 import org.apache.lucene.store.Directory;
 import org.apache.lucene.store.IOContext;
 import org.apache.lucene.store.IndexOutput;
+import org.apache.lucene.util.CodecUtil;
 
 /**
  * Lucene 4.0 FieldInfos writer.
@@ -39,10 +40,8 @@ public class Lucene40FieldInfosWriter extends FieldInfosWriter {
   /** Extension of field infos */
   static final String FIELD_INFOS_EXTENSION = "fnm";
   
-  // per-field codec support, records index values for fields
-  static final int FORMAT_START = -4;
-
-  // whenever you add a new format, make it 1 smaller (negative version logic)!
+  static final String CODEC_NAME = "Lucene40FieldInfos";
+  static final int FORMAT_START = 0;
   static final int FORMAT_CURRENT = FORMAT_START;
   
   static final byte IS_INDEXED = 0x1;
@@ -58,7 +57,7 @@ public class Lucene40FieldInfosWriter extends FieldInfosWriter {
     final String fileName = IndexFileNames.segmentFileName(segmentName, "", FIELD_INFOS_EXTENSION);
     IndexOutput output = directory.createOutput(fileName, context);
     try {
-      output.writeVInt(FORMAT_CURRENT);
+      CodecUtil.writeHeader(output, CODEC_NAME, FORMAT_CURRENT);
       output.writeVInt(infos.size());
       for (FieldInfo fi : infos) {
         IndexOptions indexOptions = fi.getIndexOptions();

lucene/core/src/java/org/apache/lucene/index/IndexWriter.java

@@ -2386,6 +2386,8 @@ public class IndexWriter implements Closeable, TwoPhaseCommit {
       // only violate the codec this way if it's preflex &
       // shares doc stores
       // nocommit what to do....
+      // cant we determine a file is a 3.x shared doc store file if hasSharedDocStore=true
+      // and the segment prefix != info.info.name instead of this stuff?
       if (Lucene3xSegmentInfoFormat.getDocStoreIsCompoundFile(info.info)) {
         codecDocStoreFiles.add(IndexFileNames.segmentFileName(dsName, "", "cfx"));
       } else {