AuroraTwinkle commented on code in PR #4642: URL: https://github.com/apache/rocketmq/pull/4642#discussion_r1693934387
########## store/src/main/java/org/apache/rocketmq/store/timer/TimerWheel.java: ########## @@ -0,0 +1,209 @@ +/* + * 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.rocketmq.store.timer; + +import org.apache.rocketmq.common.UtilAll; +import org.apache.rocketmq.common.constant.LoggerName; +import org.apache.rocketmq.logging.InternalLogger; +import org.apache.rocketmq.logging.InternalLoggerFactory; + +import java.io.File; +import java.io.FileNotFoundException; +import java.io.IOException; +import java.io.RandomAccessFile; +import java.nio.ByteBuffer; +import java.nio.MappedByteBuffer; +import java.nio.channels.FileChannel; + +public class TimerWheel { + + private static final InternalLogger log = InternalLoggerFactory.getLogger(LoggerName.STORE_LOGGER_NAME); + public static final int BLANK = -1, IGNORE = -2; + public final int slotsTotal; + public final int precisionMs; + private String fileName; + private final RandomAccessFile randomAccessFile; + private final FileChannel fileChannel; + private final MappedByteBuffer mappedByteBuffer; + private final ByteBuffer byteBuffer; + private final ThreadLocal<ByteBuffer> localBuffer = new ThreadLocal<ByteBuffer>() { + @Override + protected ByteBuffer initialValue() { + return byteBuffer.duplicate(); + } + }; + private final int wheelLength; + + public TimerWheel(String fileName, int slotsTotal, int precisionMs) throws IOException { + this.slotsTotal = slotsTotal; + this.precisionMs = precisionMs; + this.fileName = fileName; + this.wheelLength = this.slotsTotal * 2 * Slot.SIZE; + + File file = new File(fileName); + UtilAll.ensureDirOK(file.getParent()); + + try { + randomAccessFile = new RandomAccessFile(this.fileName, "rw"); + if (file.exists() && randomAccessFile.length() != 0 && + randomAccessFile.length() != wheelLength) { + throw new RuntimeException(String.format("Timer wheel length:%d != expected:%s", + randomAccessFile.length(), wheelLength)); + } + randomAccessFile.setLength(wheelLength); + fileChannel = randomAccessFile.getChannel(); + mappedByteBuffer = fileChannel.map(FileChannel.MapMode.READ_WRITE, 0, wheelLength); + assert wheelLength == mappedByteBuffer.remaining(); + this.byteBuffer = ByteBuffer.allocateDirect(wheelLength); + this.byteBuffer.put(mappedByteBuffer); + } catch (FileNotFoundException e) { + log.error("create file channel " + this.fileName + " Failed. ", e); + throw e; + } catch (IOException e) { + log.error("map file " + this.fileName + " Failed. ", e); + throw e; + } + } + + public void shutdown() { + shutdown(true); + } + + public void shutdown(boolean flush) { + if (flush) + this.flush(); + + // unmap mappedByteBuffer + UtilAll.cleanBuffer(this.mappedByteBuffer); + UtilAll.cleanBuffer(this.byteBuffer); + + try { + this.fileChannel.close(); + } catch (IOException e) { + log.error("Shutdown error in timer wheel", e); + } + } + + public void flush() { + ByteBuffer bf = localBuffer.get(); + bf.position(0); + bf.limit(wheelLength); + mappedByteBuffer.position(0); + mappedByteBuffer.limit(wheelLength); + for (int i = 0; i < wheelLength; i++) { + if (bf.get(i) != mappedByteBuffer.get(i)) { + mappedByteBuffer.put(i, bf.get(i)); + } + } + this.mappedByteBuffer.force(); + } + + public Slot getSlot(long timeMs) { + Slot slot = getRawSlot(timeMs); + if (slot.timeMs != timeMs / precisionMs * precisionMs) { + return new Slot(-1, -1, -1); + } + return slot; + } + + //testable + public Slot getRawSlot(long timeMs) { + localBuffer.get().position(getSlotIndex(timeMs) * Slot.SIZE); + return new Slot(localBuffer.get().getLong() * precisionMs, + localBuffer.get().getLong(), localBuffer.get().getLong(), localBuffer.get().getInt(), localBuffer.get().getInt()); + } + + public int getSlotIndex(long timeMs) { + return (int) (timeMs / precisionMs % (slotsTotal * 2)); + } + + public void putSlot(long timeMs, long firstPos, long lastPos) { + localBuffer.get().position(getSlotIndex(timeMs) * Slot.SIZE); + // To be compatible with previous version. + // The previous version's precision is fixed at 1000ms and it store timeMs / 1000 in slot. + localBuffer.get().putLong(timeMs / precisionMs); + localBuffer.get().putLong(firstPos); + localBuffer.get().putLong(lastPos); + } + public void putSlot(long timeMs, long firstPos, long lastPos, int num, int magic) { + localBuffer.get().position(getSlotIndex(timeMs) * Slot.SIZE); + localBuffer.get().putLong(timeMs / precisionMs); + localBuffer.get().putLong(firstPos); + localBuffer.get().putLong(lastPos); + localBuffer.get().putInt(num); + localBuffer.get().putInt(magic); + } + + public void reviseSlot(long timeMs, long firstPos, long lastPos, boolean force) { + localBuffer.get().position(getSlotIndex(timeMs) * Slot.SIZE); + + if (timeMs / precisionMs != localBuffer.get().getLong()) { + if (force) { + putSlot(timeMs, firstPos != IGNORE ? firstPos : lastPos, lastPos); + } + } else { + if (IGNORE != firstPos) { + localBuffer.get().putLong(firstPos); + } else { + localBuffer.get().getLong(); + } + if (IGNORE != lastPos) { + localBuffer.get().putLong(lastPos); + } + } + } + + //check the timerwheel to see if its stored offset > maxOffset in timerlog + public long checkPhyPos(long timeStartMs, long maxOffset) { + long minFirst = Long.MAX_VALUE; + int firstSlotIndex = getSlotIndex(timeStartMs); + for (int i = 0; i < slotsTotal * 2; i++) { Review Comment: I noticed that `slotsTotal * 2` appears multiple times. Why do we need to multiply it by 2? I don't understand, could you please help me? Thanks. @GenerousMan -- 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: commits-unsubscr...@rocketmq.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
