| /* |
| * Copyright 2018 The gRPC Authors |
| * |
| * Licensed 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 io.grpc.alts.internal; |
| |
| import io.netty.buffer.ByteBuf; |
| import io.netty.buffer.CompositeByteBuf; |
| import java.nio.ByteBuffer; |
| |
| /** Unwraps {@link ByteBuf}s into {@link ByteBuffer}s. */ |
| final class BufUnwrapper implements AutoCloseable { |
| |
| private final ByteBuffer[] singleReadBuffer = new ByteBuffer[1]; |
| private final ByteBuffer[] singleWriteBuffer = new ByteBuffer[1]; |
| |
| /** |
| * Called to get access to the underlying NIO buffers for a {@link ByteBuf} that will be used for |
| * writing. |
| */ |
| ByteBuffer[] writableNioBuffers(ByteBuf buf) { |
| // Set the writer index to the capacity to guarantee that the returned NIO buffers will have |
| // the capacity available. |
| int readerIndex = buf.readerIndex(); |
| int writerIndex = buf.writerIndex(); |
| buf.readerIndex(writerIndex); |
| buf.writerIndex(buf.capacity()); |
| |
| try { |
| return nioBuffers(buf, singleWriteBuffer); |
| } finally { |
| // Restore the writer index before returning. |
| buf.readerIndex(readerIndex); |
| buf.writerIndex(writerIndex); |
| } |
| } |
| |
| /** |
| * Called to get access to the underlying NIO buffers for a {@link ByteBuf} that will be used for |
| * reading. |
| */ |
| ByteBuffer[] readableNioBuffers(ByteBuf buf) { |
| return nioBuffers(buf, singleReadBuffer); |
| } |
| |
| @Override |
| public void close() { |
| singleReadBuffer[0] = null; |
| singleWriteBuffer[0] = null; |
| } |
| |
| /** |
| * Optimized accessor for obtaining the underlying NIO buffers for a Netty {@link ByteBuf}. Based |
| * on code from Netty's {@code SslHandler}. This method returns NIO buffers that span the readable |
| * region of the {@link ByteBuf}. |
| */ |
| private static ByteBuffer[] nioBuffers(ByteBuf buf, ByteBuffer[] singleBuffer) { |
| // As CompositeByteBuf.nioBufferCount() can be expensive (as it needs to check all composed |
| // ByteBuf to calculate the count) we will just assume a CompositeByteBuf contains more than 1 |
| // ByteBuf. The worst that can happen is that we allocate an extra ByteBuffer[] in |
| // CompositeByteBuf.nioBuffers() which is better than walking the composed ByteBuf in most |
| // cases. |
| if (!(buf instanceof CompositeByteBuf) && buf.nioBufferCount() == 1) { |
| // We know its only backed by 1 ByteBuffer so use internalNioBuffer to keep object |
| // allocation to a minimum. |
| singleBuffer[0] = buf.internalNioBuffer(buf.readerIndex(), buf.readableBytes()); |
| return singleBuffer; |
| } |
| |
| return buf.nioBuffers(); |
| } |
| } |