1 /*

     2  * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 package jdk.internal.net.http.common;

    26 

    27 import java.nio.ByteBuffer;

    28 import java.util.concurrent.ConcurrentLinkedQueue;

    29 import java.util.function.Supplier;

    30 

    31 /**

    32  *  This interface allows to recycle buffers used for SSL decryption.

    33  *  Buffers that are used for reading SSL encrypted data are typically

    34  *  very short lived, as it is necessary to aggregate their content

    35  *  before calling SSLEngine::unwrap.

    36  *  Because both reading and copying happen in the SelectorManager

    37  *  thread, then it makes it possible to pool these buffers and

    38  *  recycle them for the next socket read, instead of simply

    39  *  letting them be GC'ed. That also makes it possible to use

    40  *  direct byte buffers, and avoid another layer of copying by

    41  *  the SocketChannel implementation.

    42  *

    43  *  The HttpClientImpl has an implementation of this interface

    44  *  that allows to reuse the same 3 direct buffers for reading

    45  *  off SSL encrypted data from the socket.

    46  *  The BufferSupplier::get method is called by SocketTube

    47  *  (see SocketTube.SSLDirectBufferSource) and BufferSupplier::recycle

    48  *  is called by SSLFlowDelegate.Reader.

    49  **/

    50 public interface BufferSupplier extends Supplier<ByteBuffer> {

    51     /**

    52      * Returns a buffer to read encrypted data off the socket.

    53      * @return a buffer to read encrypted data off the socket.

    54      */

    55     ByteBuffer get();

    56 

    57     /**

    58      * Returns a buffer to the pool.

    59      *

    60      * @param buffer This must be a buffer previously obtained

    61      *               by calling BufferSupplier::get. The caller must

    62      *               not touch the buffer after returning it to

    63      *               the pool.

    64      */

    65     void recycle(ByteBuffer buffer);

    66 }

    67