/// <summary> Initialize the deleter: find all previous commits in /// the Directory, incref the files they reference, call /// the policy to let it delete commits. This will remove /// any files not referenced by any of the commits. /// </summary> /// <throws> CorruptIndexException if the index is corrupt </throws> /// <throws> IOException if there is a low-level IO error </throws> public IndexFileDeleter(Directory directory, IndexDeletionPolicy policy, SegmentInfos segmentInfos, System.IO.StreamWriter infoStream, DocumentsWriter docWriter, System.Collections.Generic.Dictionary <string, string> synced) { this.docWriter = docWriter; this.infoStream = infoStream; this.synced = synced; if (infoStream != null) { Message("init: current segments file is \"" + segmentInfos.GetCurrentSegmentFileName() + "\"; deletionPolicy=" + policy); } this.policy = policy; this.directory = directory; // First pass: walk the files and initialize our ref // counts: long currentGen = segmentInfos.GetGeneration(); IndexFileNameFilter filter = IndexFileNameFilter.GetFilter(); System.String[] files = directory.ListAll(); CommitPoint currentCommitPoint = null; for (int i = 0; i < files.Length; i++) { System.String fileName = files[i]; if (filter.Accept(null, fileName) && !fileName.Equals(IndexFileNames.SEGMENTS_GEN)) { // Add this file to refCounts with initial count 0: GetRefCount(fileName); if (fileName.StartsWith(IndexFileNames.SEGMENTS)) { // This is a commit (segments or segments_N), and // it's valid (<= the max gen). Load it, then // incref all files it refers to: if (infoStream != null) { Message("init: load commit \"" + fileName + "\""); } SegmentInfos sis = new SegmentInfos(); try { sis.Read(directory, fileName); } catch (System.IO.FileNotFoundException e) { // LUCENE-948: on NFS (and maybe others), if // you have writers switching back and forth // between machines, it's very likely that the // dir listing will be stale and will claim a // file segments_X exists when in fact it // doesn't. So, we catch this and handle it // as if the file does not exist if (infoStream != null) { Message("init: hit FileNotFoundException when loading commit \"" + fileName + "\"; skipping this commit point"); } sis = null; } catch (System.IO.IOException e) { if (SegmentInfos.GenerationFromSegmentsFileName(fileName) <= currentGen) { throw e; } else { // Most likely we are opening an index that // has an aborted "future" commit, so suppress // exc in this case sis = null; } } if (sis != null) { CommitPoint commitPoint = new CommitPoint(this, commitsToDelete, directory, sis); if (sis.GetGeneration() == segmentInfos.GetGeneration()) { currentCommitPoint = commitPoint; } commits.Add(commitPoint); IncRef(sis, true); if (lastSegmentInfos == null || sis.GetGeneration() > lastSegmentInfos.GetGeneration()) { lastSegmentInfos = sis; } } } } } if (currentCommitPoint == null) { // We did not in fact see the segments_N file // corresponding to the segmentInfos that was passed // in. Yet, it must exist, because our caller holds // the write lock. This can happen when the directory // listing was stale (eg when index accessed via NFS // client with stale directory listing cache). So we // try now to explicitly open this commit point: SegmentInfos sis = new SegmentInfos(); try { sis.Read(directory, segmentInfos.GetCurrentSegmentFileName()); } catch (System.IO.IOException e) { throw new CorruptIndexException("failed to locate current segments_N file"); } if (infoStream != null) { Message("forced open of current segments file " + segmentInfos.GetCurrentSegmentFileName()); } currentCommitPoint = new CommitPoint(this, commitsToDelete, directory, sis); commits.Add(currentCommitPoint); IncRef(sis, true); } // We keep commits list in sorted order (oldest to newest): commits.Sort(); // Now delete anything with ref count at 0. These are // presumably abandoned files eg due to crash of // IndexWriter. System.Collections.Generic.IEnumerator <System.Collections.Generic.KeyValuePair <System.String, RefCount> > it = refCounts.GetEnumerator(); while (it.MoveNext()) { System.String fileName = (System.String)it.Current.Key; RefCount rc = (RefCount)refCounts[fileName]; if (0 == rc.count) { if (infoStream != null) { Message("init: removing unreferenced file \"" + fileName + "\""); } DeleteFile(fileName); } } // Finally, give policy a chance to remove things on // startup: policy.OnInit(commits); // Always protect the incoming segmentInfos since // sometime it may not be the most recent commit Checkpoint(segmentInfos, false); startingCommitDeleted = currentCommitPoint.IsDeleted(); DeleteCommits(); }