/*

* Copyright © 2016-2025 The LmdbJava Open Source Project

*

* 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 org.lmdbjava;

import static java.util.Objects.requireNonNull;

import static org.lmdbjava.BufferProxy.MDB_VAL_STRUCT_SIZE;

import static org.lmdbjava.Library.RUNTIME;

import jnr.ffi.Pointer;

import jnr.ffi.provider.MemoryManager;

/**

* Represents off-heap memory holding a key only. Equivalent to {@link KeyVal} without the val part.

*

* @param <T> buffer type

*/

final class Key<T> implements AutoCloseable {

private static final MemoryManager MEM_MGR = RUNTIME.getMemoryManager();

private boolean closed;

private final T k;

private final BufferProxy<T> proxy;

private final Pointer ptrKey;

Key(final BufferProxy<T> proxy) {

requireNonNull(proxy);

this.proxy = proxy;

this.k = proxy.allocate();

ptrKey = MEM_MGR.allocateTemporary(MDB_VAL_STRUCT_SIZE, false);

}

@Override

public void close() {

if (closed) {

return;

}

closed = true;

proxy.deallocate(k);

}

void keyIn(final T key) {

proxy.in(key, ptrKey);

}

Pointer pointer() {

return ptrKey;

}

}