/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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 org.apache.ignite.internal.processors.cache;

import java.nio.ByteBuffer;

/**
 * Cache object container that accumulates partial binary data
 * unless all of them ready.
 */
public class IncompleteCacheObject extends IncompleteObject<CacheObject> {
    /** 4 bytes - cache object length, 1 byte - type. */
    public static final int HEAD_LEN = 5;

    /** */
    private byte type;

    /** */
    private int headOff;

    /** */
    private byte[] head;

    /**
     * @param buf Byte buffer.
     */
    public IncompleteCacheObject(final ByteBuffer buf) {
        if (buf.remaining() >= HEAD_LEN) {
            data = new byte[buf.getInt()];
            type = buf.get();
        }
        // We cannot fully read head to initialize data buffer.
        // Start partial read of header.
        else
            head = new byte[HEAD_LEN];
    }

    /** {@inheritDoc} */
    @Override public void readData(ByteBuffer buf) {
        if (data == null) {
            assert head != null;

            final int len = Math.min(HEAD_LEN - headOff, buf.remaining());

            buf.get(head, headOff, len);

            headOff += len;

            if (headOff == HEAD_LEN) {
                final ByteBuffer headBuf = ByteBuffer.wrap(head);

                headBuf.order(buf.order());

                data = new byte[headBuf.getInt()];
                type = headBuf.get();
            }
        }

        if (data != null)
            super.readData(buf);
    }

    /**
     * @return Data type.
     */
    public byte type() {
        return type;
    }
}