| /* |
| * 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.hadoop.hdds.scm.storage; |
| |
| import com.google.common.base.Preconditions; |
| import org.apache.hadoop.hdds.scm.ByteStringConversion; |
| import org.apache.ratis.thirdparty.com.google.protobuf.ByteString; |
| |
| import java.nio.ByteBuffer; |
| import java.util.ArrayList; |
| import java.util.List; |
| import java.util.function.Function; |
| |
| /** |
| * This class creates and manages pool of n buffers. |
| */ |
| public class BufferPool { |
| |
| private List<ByteBuffer> bufferList; |
| private int currentBufferIndex; |
| private final int bufferSize; |
| private final int capacity; |
| private final Function<ByteBuffer, ByteString> byteStringConversion; |
| |
| public BufferPool(int bufferSize, int capacity) { |
| this(bufferSize, capacity, |
| ByteStringConversion.createByteBufferConversion(null)); |
| } |
| |
| public BufferPool(int bufferSize, int capacity, |
| Function<ByteBuffer, ByteString> byteStringConversion){ |
| this.capacity = capacity; |
| this.bufferSize = bufferSize; |
| bufferList = new ArrayList<>(capacity); |
| currentBufferIndex = -1; |
| this.byteStringConversion = byteStringConversion; |
| } |
| |
| public Function<ByteBuffer, ByteString> byteStringConversion(){ |
| return byteStringConversion; |
| } |
| |
| public ByteBuffer getCurrentBuffer() { |
| return currentBufferIndex == -1 ? null : bufferList.get(currentBufferIndex); |
| } |
| |
| /** |
| * If the currentBufferIndex is less than the buffer size - 1, |
| * it means, the next buffer in the list has been freed up for |
| * rewriting. Reuse the next available buffer in such cases. |
| * |
| * In case, the currentBufferIndex == buffer.size and buffer size is still |
| * less than the capacity to be allocated, just allocate a buffer of size |
| * chunk size. |
| * |
| */ |
| public ByteBuffer allocateBufferIfNeeded() { |
| ByteBuffer buffer = getCurrentBuffer(); |
| if (buffer != null && buffer.hasRemaining()) { |
| return buffer; |
| } |
| if (currentBufferIndex < bufferList.size() - 1) { |
| buffer = getBuffer(currentBufferIndex + 1); |
| } else { |
| buffer = ByteBuffer.allocate(bufferSize); |
| bufferList.add(buffer); |
| } |
| Preconditions.checkArgument(bufferList.size() <= capacity); |
| currentBufferIndex++; |
| // TODO: Turn the below precondition check on when Standalone pipeline |
| // is removed in the write path in tests |
| // Preconditions.checkArgument(buffer.position() == 0); |
| return buffer; |
| } |
| |
| public void releaseBuffer(ByteBuffer byteBuffer) { |
| // always remove from head of the list and append at last |
| ByteBuffer buffer = bufferList.remove(0); |
| // Ensure the buffer to be removed is always at the head of the list. |
| Preconditions.checkArgument(buffer.equals(byteBuffer)); |
| buffer.clear(); |
| bufferList.add(buffer); |
| Preconditions.checkArgument(currentBufferIndex >= 0); |
| currentBufferIndex--; |
| } |
| |
| public void clearBufferPool() { |
| bufferList.clear(); |
| currentBufferIndex = -1; |
| } |
| |
| public void checkBufferPoolEmpty() { |
| Preconditions.checkArgument(computeBufferData() == 0); |
| } |
| |
| public long computeBufferData() { |
| return bufferList.stream().mapToInt(value -> value.position()) |
| .sum(); |
| } |
| |
| public int getSize() { |
| return bufferList.size(); |
| } |
| |
| public ByteBuffer getBuffer(int index) { |
| return bufferList.get(index); |
| } |
| |
| int getCurrentBufferIndex() { |
| return currentBufferIndex; |
| } |
| |
| } |