content: /*
   * Copyright (c) 2016, 2021, Oracle and/or its affiliates.
   *
   * This program is free software; you can redistribute it and/or modify it under
   * the terms of the GNU General Public License, version 2.0, as published by the
   * Free Software Foundation.
   *
   * This program is also distributed with certain software (including but not
   * limited to OpenSSL) that is licensed under separate terms, as designated in a
   * particular file or component or in included license documentation. The
   * authors of MySQL hereby grant you an additional permission to link the
   * program and your derivative works with the separately licensed software that
   * they have included with MySQL.
   *
   * Without limiting anything contained in the foregoing, this file, which is
   * part of MySQL Connector/J, is also subject to the Universal FOSS Exception,
   * version 1.0, a copy of which can be found at
   * http://oss.oracle.com/licenses/universal-foss-exception.
   *
   * This program is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
   * FOR A PARTICULAR PURPOSE. See the GNU General Public License, version 2.0,
   * for more details.
   *
   * You should have received a copy of the GNU General Public License along with
   * this program; if not, write to the Free Software Foundation, Inc.,
   * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
   */
  
  package com.mysql.cj.protocol.a;
  
  import java.io.IOException;
  import java.util.LinkedList;
  import java.util.Optional;
  
  import com.mysql.cj.Messages;
  import com.mysql.cj.conf.RuntimeProperty;
  import com.mysql.cj.protocol.MessageReader;
  import com.mysql.cj.util.StringUtils;
  
  /**
   * A decorating {@link MessageReader} which put debugging info to a ring-buffer.
   */
  public class DebugBufferingPacketReader implements MessageReader<NativePacketHeader, NativePacketPayload> {
  
      /** Max number of bytes to dump when tracing the protocol */
      private static final int MAX_PACKET_DUMP_LENGTH = 1024;
      private static final int DEBUG_MSG_LEN = 96;
  
      private MessageReader<NativePacketHeader, NativePacketPayload> packetReader;
      private LinkedList<StringBuilder> packetDebugBuffer;
      private RuntimeProperty<Integer> packetDebugBufferSize;
      private String lastHeaderPayload = "";
  
      private boolean packetSequenceReset = false;
  
      public DebugBufferingPacketReader(MessageReader<NativePacketHeader, NativePacketPayload> packetReader, LinkedList<StringBuilder> packetDebugBuffer,
              RuntimeProperty<Integer> packetDebugBufferSize) {
          this.packetReader = packetReader;
          this.packetDebugBuffer = packetDebugBuffer;
          this.packetDebugBufferSize = packetDebugBufferSize;
      }
  
      @Override
      public NativePacketHeader readHeader() throws IOException {
          byte prevPacketSeq = this.packetReader.getMessageSequence();
          return readHeaderLocal(prevPacketSeq, this.packetReader.readHeader());
      }
  
      @Override
      public NativePacketHeader probeHeader() throws IOException {
          byte prevPacketSeq = this.packetReader.getMessageSequence();
          return readHeaderLocal(prevPacketSeq, this.packetReader.probeHeader());
      }
  
      private NativePacketHeader readHeaderLocal(byte prevPacketSeq, NativePacketHeader hdr) throws IOException {
          // Normally we shouldn't get into situation of getting packets out of order from server,
          // so we do this check only in debug mode.
          byte currPacketSeq = hdr.getMessageSequence();
          if (!this.packetSequenceReset) {
  
              if ((currPacketSeq == -128) && (prevPacketSeq != 127)) {
                  throw new IOException(Messages.getString("PacketReader.9", new Object[] { "-128", currPacketSeq }));
              }
  
              if ((prevPacketSeq == -1) && (currPacketSeq != 0)) {
                  throw new IOException(Messages.getString("PacketReader.9", new Object[] { "-1", currPacketSeq }));
              }
  
              if ((currPacketSeq != -128) && (prevPacketSeq != -1) && (currPacketSeq != (prevPacketSeq + 1))) {
                  throw new IOException(Messages.getString("PacketReader.9", new Object[] { (prevPacketSeq + 1), currPacketSeq }));
              }
  
          } else {
              this.packetSequenceReset = false;
          }
  
          this.lastHeaderPayload = StringUtils.dumpAsHex(hdr.getBuffer().array(), NativeConstants.HEADER_LENGTH);
  
          return hdr;
      }
  
      @Override
      public NativePacketPayload readMessage(Optional<NativePacketPayload> reuse, NativePacketHeader header) throws IOException {
          int packetLength = header.getMessageSize();
          NativePacketPayload buf = this.packetReader.readMessage(reuse, header);
  
          int bytesToDump = Math.min(MAX_PACKET_DUMP_LENGTH, packetLength);
          String PacketPayloadImpl = StringUtils.dumpAsHex(buf.getByteBuffer(), bytesToDump);
  
          StringBuilder packetDump = new StringBuilder(DEBUG_MSG_LEN + NativeConstants.HEADER_LENGTH + PacketPayloadImpl.length());
          packetDump.append("Server ");
          packetDump.append(reuse.isPresent() ? "(re-used) " : "(new) ");
          packetDump.append(buf.toString());
          packetDump.append(" --------------------> Client\n");
          packetDump.append("\nPacket payload:\n\n");
          packetDump.append(this.lastHeaderPayload);
          packetDump.append(PacketPayloadImpl);
  
          if (bytesToDump == MAX_PACKET_DUMP_LENGTH) {
              packetDump.append("\nNote: Packet of " + packetLength + " bytes truncated to " + MAX_PACKET_DUMP_LENGTH + " bytes.\n");
          }
  
          if ((this.packetDebugBuffer.size() + 1) > this.packetDebugBufferSize.getValue()) {
              this.packetDebugBuffer.removeFirst();
          }
  
          this.packetDebugBuffer.addLast(packetDump);
  
          return buf;
      }
  
      @Override
      public NativePacketPayload probeMessage(Optional<NativePacketPayload> reuse, NativePacketHeader header) throws IOException {
          int packetLength = header.getMessageSize();
          NativePacketPayload buf = this.packetReader.probeMessage(reuse, header);
  
          int bytesToDump = Math.min(MAX_PACKET_DUMP_LENGTH, packetLength);
          String PacketPayloadImpl = StringUtils.dumpAsHex(buf.getByteBuffer(), bytesToDump);
  
          StringBuilder packetDump = new StringBuilder(DEBUG_MSG_LEN + NativeConstants.HEADER_LENGTH + PacketPayloadImpl.length());
          packetDump.append("Server ");
          packetDump.append(reuse.isPresent() ? "(re-used) " : "(new) ");
          packetDump.append(buf.toString());
          packetDump.append(" --------------------> Client\n");
          packetDump.append("\nPacket payload:\n\n");
          packetDump.append(this.lastHeaderPayload);
          packetDump.append(PacketPayloadImpl);
  
          if (bytesToDump == MAX_PACKET_DUMP_LENGTH) {
              packetDump.append("\nNote: Packet of " + packetLength + " bytes truncated to " + MAX_PACKET_DUMP_LENGTH + " bytes.\n");
          }
  
          if ((this.packetDebugBuffer.size() + 1) > this.packetDebugBufferSize.getValue()) {
              this.packetDebugBuffer.removeFirst();
          }
  
          this.packetDebugBuffer.addLast(packetDump);
  
          return buf;
      }
  
      @Override
      public byte getMessageSequence() {
          return this.packetReader.getMessageSequence();
      }
  
      @Override
      public void resetMessageSequence() {
          this.packetReader.resetMessageSequence();
          this.packetSequenceReset = true;
      }
  
      @Override
      public MessageReader<NativePacketHeader, NativePacketPayload> undecorateAll() {
          return this.packetReader.undecorateAll();
      }
  
      @Override
      public MessageReader<NativePacketHeader, NativePacketPayload> undecorate() {
          return this.packetReader;
      }
  
  }
  