segmentinfos.cs

Lucene.Net 版本源码 测试通过

/*
 * 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.
 */

using System;
using Directory = Lucene.Net.Store.Directory;
using IndexInput = Lucene.Net.Store.IndexInput;
using IndexOutput = Lucene.Net.Store.IndexOutput;

namespace Lucene.Net.Index
{
	
	[Serializable]
	public sealed class SegmentInfos : System.Collections.ArrayList
	{
		private class AnonymousClassFindSegmentsFile:FindSegmentsFile
		{
			private void  InitBlock(SegmentInfos enclosingInstance)
			{
				this.enclosingInstance = enclosingInstance;
			}
			private SegmentInfos enclosingInstance;
			public SegmentInfos Enclosing_Instance
			{
				get
				{
					return enclosingInstance;
				}
				
			}
			internal AnonymousClassFindSegmentsFile(SegmentInfos enclosingInstance, Lucene.Net.Store.Directory Param1):base(Param1)
			{
				InitBlock(enclosingInstance);
			}
			
			public override System.Object DoBody(System.String segmentFileName)
			{
				Enclosing_Instance.Read(directory, segmentFileName);
				return null;
			}
		}
		private class AnonymousClassFindSegmentsFile1:FindSegmentsFile
		{
			internal AnonymousClassFindSegmentsFile1(Lucene.Net.Store.Directory Param1):base(Param1)
			{
			}
			public override System.Object DoBody(System.String segmentFileName)
			{
				
				IndexInput input = directory.OpenInput(segmentFileName);
				
				int format = 0;
				long version = 0;
				try
				{
					format = input.ReadInt();
					if (format < 0)
					{
						if (format < Lucene.Net.Index.SegmentInfos.FORMAT_SINGLE_NORM_FILE)
							throw new System.IO.IOException("Unknown format version: " + format);
						version = input.ReadLong(); // read version
					}
				}
				finally
				{
					input.Close();
				}
				
				if (format < 0)
					return (long) version;
				
				// We cannot be sure about the format of the file.
				// Therefore we have to read the whole file and cannot simply seek to the version entry.
				SegmentInfos sis = new SegmentInfos();
				sis.Read(directory, segmentFileName);
				return (long) sis.GetVersion();
			}
		}
		
		/// <summary>The file format version, a negative number. </summary>
		/* Works since counter, the old 1st entry, is always >= 0 */
		public const int FORMAT = - 1;
		
		/// <summary>This format adds details used for lockless commits.  It differs
		/// slightly from the previous format in that file names
		/// are never re-used (write once).  Instead, each file is
		/// written to the next generation.  For example,
		/// segments_1, segments_2, etc.  This allows us to not use
		/// a commit lock.  See <a
		/// href="http://lucene.apache.org/java/docs/fileformats.html">file
		/// formats</a> for details.
		/// </summary>
		public const int FORMAT_LOCKLESS = - 2;
		
		/// <summary>This is the current file format written.  It adds a
		/// "hasSingleNormFile" flag into each segment info.
		/// See <a href="http://issues.apache.org/jira/browse/LUCENE-756">LUCENE-756</a>
		/// for details.
		/// </summary>
		public const int FORMAT_SINGLE_NORM_FILE = - 3;
		
		public int counter = 0; // used to name new segments
		/// <summary> counts how often the index has been changed by adding or deleting docs.
		/// starting with the current time in milliseconds forces to create unique version numbers.
		/// </summary>
		private long version = System.DateTime.Now.Millisecond;
		
		private long generation = 0; // generation of the "segments_N" for the next commit
		private long lastGeneration = 0; // generation of the "segments_N" file we last successfully read
		// or wrote; this is normally the same as generation except if
		// there was an IOException that had interrupted a commit
		
		/// <summary> If non-null, information about loading segments_N files</summary>
		/// <seealso cref="#setInfoStream.">
		/// </seealso>
		private static System.IO.TextWriter infoStream;
		
		public SegmentInfo Info(int i)
		{
			return (SegmentInfo) this[i];
		}
		
		/// <summary> Get the generation (N) of the current segments_N file
		/// from a list of files.
		/// 
		/// </summary>
		/// <param name="files">-- array of file names to check
		/// </param>
		public static long GetCurrentSegmentGeneration(System.String[] files)
		{
			if (files == null)
			{
				return - 1;
			}
			long max = - 1;
			int prefixLen = IndexFileNames.SEGMENTS.Length + 1;
			for (int i = 0; i < files.Length; i++)
			{
				System.String file = files[i];
				if (file.StartsWith(IndexFileNames.SEGMENTS) && !file.Equals(IndexFileNames.SEGMENTS_GEN))
				{
					if (file.Equals(IndexFileNames.SEGMENTS))
					{
						// Pre lock-less commits:
						if (max == - 1)
						{
							max = 0;
						}
					}
					else
					{
						long v = System.Convert.ToInt64(file.Substring(prefixLen), 16);
						if (v > max)
						{
							max = v;
						}
					}
				}
			}
			return max;
		}
		
		/// <summary> Get the generation (N) of the current segments_N file
		/// in the directory.
		/// 
		/// </summary>
		/// <param name="directory">-- directory to search for the latest segments_N file
		/// </param>
		public static long GetCurrentSegmentGeneration(Directory directory)
		{
			System.String[] files = directory.List();
			if (files == null)
			{
				throw new System.IO.IOException("Cannot read directory " + directory);
			}
			return GetCurrentSegmentGeneration(files);
		}
		
		/// <summary> Get the filename of the current segments_N file
		/// from a list of files.
		/// 
		/// </summary>
		/// <param name="files">-- array of file names to check
		/// </param>
		
		public static System.String GetCurrentSegmentFileName(System.String[] files)
		{
			return IndexFileNames.FileNameFromGeneration(IndexFileNames.SEGMENTS, "", GetCurrentSegmentGeneration(files));
		}
		
		/// <summary> Get the filename of the current segments_N file
		/// in the directory.
		/// 
		/// </summary>
		/// <param name="directory">-- directory to search for the latest segments_N file
		/// </param>
		public static System.String GetCurrentSegmentFileName(Directory directory)
		{
			return IndexFileNames.FileNameFromGeneration(IndexFileNames.SEGMENTS, "", GetCurrentSegmentGeneration(directory));
		}
		
		/// <summary> Get the segments_N filename in use by this segment infos.</summary>
		public System.String GetCurrentSegmentFileName()
		{
			return IndexFileNames.FileNameFromGeneration(IndexFileNames.SEGMENTS, "", lastGeneration);
		}
		
		/// <summary> Get the next segments_N filename that will be written.</summary>
		public System.String GetNextSegmentFileName()
		{
			long nextGeneration;
			
			if (generation == - 1)
			{
				nextGeneration = 1;
			}
			else
			{
				nextGeneration = generation + 1;
			}
			return IndexFileNames.FileNameFromGeneration(IndexFileNames.SEGMENTS, "", nextGeneration);
		}
		
		/// <summary> Read a particular segmentFileName.  Note that this may
		/// throw an IOException if a commit is in process.
		/// 
		/// </summary>
		/// <param name="directory">-- directory containing the segments file
		/// </param>
		/// <param name="segmentFileName">-- segment file to load
		/// </param>
		public void  Read(Directory directory, System.String segmentFileName)
		{
			bool success = false;
			
			IndexInput input = directory.OpenInput(segmentFileName);
			
			if (segmentFileName.Equals(IndexFileNames.SEGMENTS))
			{
				generation = 0;
			}
			else
			{
				generation = System.Convert.ToInt64(segmentFileName.Substring(1 + IndexFileNames.SEGMENTS.Length), 16);
			}
			lastGeneration = generation;
			
			try
			{
				int format = input.ReadInt();
				if (format < 0)
				{
					// file contains explicit format info
					// check that it is a format we can understand
					if (format < FORMAT_SINGLE_NORM_FILE)
						throw new System.IO.IOException("Unknown format version: " + format);
					version = input.ReadLong(); // read version
					counter = input.ReadInt(); // read counter
				}
				else
				{
					// file is in old format without explicit format info
					counter = format;
				}
				
				for (int i = input.ReadInt(); i > 0; i--)
				{
					// read segmentInfos
					Add(new SegmentInfo(directory, format, input));
				}
				
				if (format >= 0)
				{
					// in old format the version number may be at the end of the file
					if (input.GetFilePointer() >= input.Length())
						version = System.DateTime.Now.Millisecond;
					// old file format without version number
					else
						version = input.ReadLong(); // read version
				}
				success = true;
			}
			finally
			{
				input.Close();
				if (!success)
				{
					// Clear any segment infos we had loaded so we
					// have a clean slate on retry:
					Clear();
				}
			}
		}
		/// <summary> This version of read uses the retry logic (for lock-less
		/// commits) to find the right segments file to load.
		/// </summary>
		public void  Read(Directory directory)
		{
			
			generation = lastGeneration = - 1;
			
			new AnonymousClassFindSegmentsFile(this, directory).run();
		}
		
		public void  Write(Directory directory)
		{
			
			System.String segmentFileName = GetNextSegmentFileName();
			
			// Always advance the generation on write:
			if (generation == - 1)
			{
				generation = 1;
			}
			else
			{
				generation++;
			}
			
			IndexOutput output = directory.CreateOutput(segmentFileName);
			
			try
			{
				output.WriteInt(FORMAT_SINGLE_NORM_FILE); // write FORMAT
				output.WriteLong(++version); // every write changes
				// the index
				output.WriteInt(counter); // write counter
				output.WriteInt(Count); // write infos
				for (int i = 0; i < Count; i++)
				{
					Info(i).Write(output);
				}
			}
			finally
			{
				output.Close();
			}
			
			try
			{
				output = directory.CreateOutput(IndexFileNames.SEGMENTS_GEN);
				try
				{
					output.WriteInt(FORMAT_LOCKLESS);
					output.WriteLong(generation);
					output.WriteLong(generation);
				}
				finally
				{
					output.Close();
				}
			}
			catch (System.IO.IOException e)
			{
				// It's OK if we fail to write this file since it's
				// used only as one of the retry fallbacks.