/*
 * 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.cassandra.utils.memory;

import java.nio.ByteBuffer;

import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.cassandra.utils.concurrent.OpOrder;

/**
 * Wraps calls to a PoolAllocator with the provided writeOp. Also doubles as a Function that clones Cells
 * using itself
 */
public final class ContextAllocator extends AbstractAllocator
{
    private final OpOrder.Group opGroup;
    private final MemtableBufferAllocator allocator;

    public ContextAllocator(OpOrder.Group opGroup, MemtableBufferAllocator allocator)
    {
        this.opGroup = opGroup;
        this.allocator = allocator;
    }

    @Override
    public ByteBuffer clone(ByteBuffer buffer)
    {
        assert buffer != null;
        if (buffer.remaining() == 0)
            return ByteBufferUtil.EMPTY_BYTE_BUFFER;
        ByteBuffer cloned = allocate(buffer.remaining());

        cloned.mark();
        cloned.put(buffer.duplicate());
        cloned.reset();
        return cloned;
    }

    public ByteBuffer allocate(int size)
    {
        return allocator.allocate(size, opGroup);
    }
}