| /* |
| * 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.hbase.ipc; |
| |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| import java.nio.channels.GatheringByteChannel; |
| import java.util.ArrayList; |
| import java.util.List; |
| |
| import org.apache.hadoop.hbase.classification.InterfaceAudience; |
| |
| /** |
| * Chain of ByteBuffers. |
| * Used writing out an array of byte buffers. Writes in chunks. |
| */ |
| @InterfaceAudience.Private |
| class BufferChain { |
| private final ByteBuffer[] buffers; |
| private int remaining = 0; |
| private int bufferOffset = 0; |
| |
| BufferChain(ByteBuffer ... buffers) { |
| // Some of the incoming buffers can be null |
| List<ByteBuffer> bbs = new ArrayList<ByteBuffer>(buffers.length); |
| for (ByteBuffer b : buffers) { |
| if (b == null) continue; |
| bbs.add(b); |
| this.remaining += b.remaining(); |
| } |
| this.buffers = bbs.toArray(new ByteBuffer[bbs.size()]); |
| } |
| |
| BufferChain(List<ByteBuffer> buffers) { |
| for (ByteBuffer b : buffers) { |
| this.remaining += b.remaining(); |
| } |
| this.buffers = buffers.toArray(new ByteBuffer[buffers.size()]); |
| } |
| |
| /** |
| * Expensive. Makes a new buffer to hold a copy of what is in contained ByteBuffers. This |
| * call drains this instance; it cannot be used subsequent to the call. |
| * @return A new byte buffer with the content of all contained ByteBuffers. |
| */ |
| byte [] getBytes() { |
| if (!hasRemaining()) throw new IllegalAccessError(); |
| byte [] bytes = new byte [this.remaining]; |
| int offset = 0; |
| for (ByteBuffer bb: this.buffers) { |
| int length = bb.remaining(); |
| bb.get(bytes, offset, length); |
| offset += length; |
| } |
| return bytes; |
| } |
| |
| boolean hasRemaining() { |
| return remaining > 0; |
| } |
| |
| /** |
| * Write out our chain of buffers in chunks |
| * @param channel Where to write |
| * @param chunkSize Size of chunks to write. |
| * @return Amount written. |
| * @throws IOException |
| */ |
| long write(GatheringByteChannel channel, int chunkSize) throws IOException { |
| int chunkRemaining = chunkSize; |
| ByteBuffer lastBuffer = null; |
| int bufCount = 0; |
| int restoreLimit = -1; |
| |
| while (chunkRemaining > 0 && bufferOffset + bufCount < buffers.length) { |
| lastBuffer = buffers[bufferOffset + bufCount]; |
| if (!lastBuffer.hasRemaining()) { |
| bufferOffset++; |
| continue; |
| } |
| bufCount++; |
| if (lastBuffer.remaining() > chunkRemaining) { |
| restoreLimit = lastBuffer.limit(); |
| lastBuffer.limit(lastBuffer.position() + chunkRemaining); |
| chunkRemaining = 0; |
| break; |
| } else { |
| chunkRemaining -= lastBuffer.remaining(); |
| } |
| } |
| assert lastBuffer != null; |
| if (chunkRemaining == chunkSize) { |
| assert !hasRemaining(); |
| // no data left to write |
| return 0; |
| } |
| try { |
| long ret = channel.write(buffers, bufferOffset, bufCount); |
| if (ret > 0) { |
| remaining -= ret; |
| } |
| return ret; |
| } finally { |
| if (restoreLimit >= 0) { |
| lastBuffer.limit(restoreLimit); |
| } |
| } |
| } |
| } |