sashapolo commented on code in PR #6661: URL: https://github.com/apache/ignite-3/pull/6661#discussion_r2391036624
########## modules/raft/src/main/java/org/apache/ignite/internal/raft/storage/segstore/GroupIndexMeta.java: ########## @@ -0,0 +1,77 @@ +/* + * 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. + */ + +package org.apache.ignite.internal.raft.storage.segstore; + +import java.lang.invoke.MethodHandles; +import java.lang.invoke.VarHandle; +import org.jetbrains.annotations.Nullable; + +/** + * Represents in-memory meta information about a particular Raft group stored in an index file. + */ +class GroupIndexMeta { + private static final VarHandle FILE_METAS_VH; + + static { + try { + FILE_METAS_VH = MethodHandles.lookup().findVarHandle(GroupIndexMeta.class, "fileMetas", IndexFileMetaArray.class); + } catch (ReflectiveOperationException e) { + throw new ExceptionInInitializerError(e); + } + } + + private final int startFileIndex; + + @SuppressWarnings("FieldMayBeFinal") // Updated through a VarHandle. + private volatile IndexFileMetaArray fileMetas; + + GroupIndexMeta(int startFileIndex, IndexFileMeta startFileMeta) { + this.startFileIndex = startFileIndex; + this.fileMetas = new IndexFileMetaArray(startFileMeta); + } + + void addIndexMeta(IndexFileMeta indexFileMeta) { + IndexFileMetaArray fileMetas = this.fileMetas; + + IndexFileMetaArray newFileMetas = fileMetas.add(indexFileMeta); + + // Simple assignment would suffice, since we only have one thread writing to this field, but we use compareAndSet to verify + // this invariant, just in case. + boolean updated = FILE_METAS_VH.compareAndSet(this, fileMetas, newFileMetas); + + assert updated : "Concurrent writes detected"; + } + + /** + * Returns a file pointer that uniquely identifies the index file for the given log index or {@code null} of no such file exists. + */ + @Nullable + IndexFilePointer indexFilePointer(long logIndex) { + IndexFileMetaArray fileMetas = this.fileMetas; + + int arrayIndex = fileMetas.find(logIndex); Review Comment: Because this index is also used to calculate the ordinal of the index file. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
