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.Optional;
  
  import com.mysql.cj.Messages;
  import com.mysql.cj.conf.RuntimeProperty;
  import com.mysql.cj.exceptions.CJPacketTooBigException;
  import com.mysql.cj.protocol.MessageReader;
  import com.mysql.cj.protocol.SocketConnection;
  
  /**
   * Simple implementation of {@link MessageReader} which handles the receiving of logical MySQL packets from the provided socket input stream.
   * Multi-packets are handled outside of this reader.
   */
  public class SimplePacketReader implements MessageReader<NativePacketHeader, NativePacketPayload> {
  
      protected SocketConnection socketConnection;
      protected RuntimeProperty<Integer> maxAllowedPacket;
  
      private byte readPacketSequence = -1;
  
      NativePacketHeader lastHeader = null;
      NativePacketPayload lastMessage = null;
  
      public SimplePacketReader(SocketConnection socketConnection, RuntimeProperty<Integer> maxAllowedPacket) {
          this.socketConnection = socketConnection;
          this.maxAllowedPacket = maxAllowedPacket;
      }
  
      @Override
      public NativePacketHeader readHeader() throws IOException {
          if (this.lastHeader == null) {
              return readHeaderLocal();
          }
          NativePacketHeader hdr = this.lastHeader;
          this.lastHeader = null;
          this.readPacketSequence = hdr.getMessageSequence();
          return hdr;
      }
  
      @Override
      public NativePacketHeader probeHeader() throws IOException {
          this.lastHeader = readHeaderLocal();
          return this.lastHeader;
      }
  
      private NativePacketHeader readHeaderLocal() throws IOException {
          NativePacketHeader hdr = new NativePacketHeader();
  
          try {
              this.socketConnection.getMysqlInput().readFully(hdr.getBuffer().array(), 0, NativeConstants.HEADER_LENGTH);
              int packetLength = hdr.getMessageSize();
              if (packetLength > this.maxAllowedPacket.getValue()) {
                  throw new CJPacketTooBigException(packetLength, this.maxAllowedPacket.getValue());
              }
          } catch (IOException | CJPacketTooBigException e) {
              try {
                  this.socketConnection.forceClose();
              } catch (Exception ex) {
                  // ignore
              }
              throw e;
          }
  
          this.readPacketSequence = hdr.getMessageSequence();
          return hdr;
      }
  
      @Override
      public NativePacketPayload readMessage(Optional<NativePacketPayload> reuse, NativePacketHeader header) throws IOException {
          if (this.lastMessage == null) {
              return readMessageLocal(reuse, header);
          }
          NativePacketPayload buf = this.lastMessage;
          this.lastMessage = null;
          return buf;
      }
  
      @Override
      public NativePacketPayload probeMessage(Optional<NativePacketPayload> reuse, NativePacketHeader header) throws IOException {
          this.lastMessage = readMessageLocal(reuse, header);
          return this.lastMessage;
      }
  
      private NativePacketPayload readMessageLocal(Optional<NativePacketPayload> reuse, NativePacketHeader header) throws IOException {
          try {
              int packetLength = header.getMessageSize();
              NativePacketPayload message;
              if (reuse.isPresent()) {
                  message = reuse.get();
                  // Set the Buffer to it's original state
                  message.setPosition(0);
                  // Do we need to re-alloc the byte buffer?
                  if (message.getByteBuffer().length < packetLength) {
                      // Note: We actually check the length of the buffer, rather than getBufLength(), because getBufLength()
                      // is not necessarily the actual length of the byte array used as the buffer
                      message.setByteBuffer(new byte[packetLength]);
                  }
  
                  // Set the new length
                  message.setPayloadLength(packetLength);
              } else {
                  message = new NativePacketPayload(new byte[packetLength]);
              }
  
              // Read the data from the server
              int numBytesRead = this.socketConnection.getMysqlInput().readFully(message.getByteBuffer(), 0, packetLength);
              if (numBytesRead != packetLength) {
                  throw new IOException(Messages.getString("PacketReader.1", new Object[] { packetLength, numBytesRead }));
              }
              return message;
  
          } catch (IOException e) {
              try {
                  this.socketConnection.forceClose();
              } catch (Exception ex) {
                  // ignore
              }
              throw e;
          }
      }
  
      @Override
      public byte getMessageSequence() {
          return this.readPacketSequence;
      }
  
      @Override
      public void resetMessageSequence() {
          this.readPacketSequence = 0;
      }
  
  }
  