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/**
 * Copyright [2009-2010] [dennis zhuang([email protected])] 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
 */
/**
 * Copyright [2009-2010] [dennis zhuang([email protected])] 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 net.rubyeye.xmemcached.command.text;

import java.nio.ByteBuffer;
import java.util.concurrent.CountDownLatch;
import net.rubyeye.xmemcached.command.CommandType;
import net.rubyeye.xmemcached.impl.MemcachedTCPSession;
import net.rubyeye.xmemcached.transcoders.Transcoder;
import net.rubyeye.xmemcached.utils.ByteUtils;

/**
 * CAS command for text protocol
 * 
 * @author dennis
 * 
 */
public class TextCASCommand extends TextStoreCommand {

  @SuppressWarnings("unchecked")
  public TextCASCommand(String key, byte[] keyBytes, CommandType cmdType, CountDownLatch latch,
      int exp, long cas, Object value, boolean noreply, Transcoder transcoder) {
    super(key, keyBytes, cmdType, latch, exp, cas, value, noreply, transcoder);
  }

  private FailStatus failStatus;

  static enum FailStatus {
    NOT_FOUND, EXISTS
  }

  @Override
  public final boolean decode(MemcachedTCPSession session, ByteBuffer buffer) {

    if (buffer == null || !buffer.hasRemaining())
      return false;
    if (result == null) {
      if (buffer.remaining() < 2)
        return false;
      byte first = buffer.get(buffer.position());
      byte second = buffer.get(buffer.position() + 1);
      if (first == 'S' && second == 'T') {
        setResult(Boolean.TRUE);
        countDownLatch();
        // STORED\r\n
        return ByteUtils.stepBuffer(buffer, 8);
      } else if (first == 'N') {
        setResult(Boolean.FALSE);
        countDownLatch();
        failStatus = FailStatus.NOT_FOUND;
        // NOT_FOUND\r\n
        return ByteUtils.stepBuffer(buffer, 11);
      } else if (first == 'E' && second == 'X') {
        setResult(Boolean.FALSE);
        countDownLatch();
        failStatus = FailStatus.EXISTS;
        // EXISTS\r\n
        return ByteUtils.stepBuffer(buffer, 8);
      } else
        return decodeError(session, buffer);
    } else {
      Boolean result = (Boolean) this.result;
      if (result) {
        return ByteUtils.stepBuffer(buffer, 8);
      } else {
        switch (this.failStatus) {
          case NOT_FOUND:
            return ByteUtils.stepBuffer(buffer, 11);
          case EXISTS:
            return ByteUtils.stepBuffer(buffer, 8);
          default:
            return decodeError(session, buffer);
        }
      }
    }
  }
}