netty-incubator-buffer-api/buffer-api/src/main/java/io/netty/buffer/api/AllocatorControl.java

63 lines
2.6 KiB
Java

/*
* Copyright 2020 The Netty Project
*
* The Netty Project 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:
*
* https://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 io.netty.buffer.api;
/**
* Methods for accessing and controlling the internals of an allocator.
* This interface is intended to be used by implementors of the {@link BufferAllocator}, {@link Buffer} and
* {@link MemoryManager} interfaces.
*/
public interface AllocatorControl {
/**
* Allocate a buffer that is not tethered to any particular {@link Buffer} object,
* and return the recoverable memory object from it.
* <p>
* This allows a buffer to implement {@link Buffer#ensureWritable(int)} by having new memory allocated to it,
* without that memory being attached to some other lifetime.
*
* @param originator The buffer that originated the request for an untethered memory allocated.
* @param size The size of the requested memory allocation, in bytes.
* @return A {@link UntetheredMemory} object that is the requested allocation.
*/
UntetheredMemory allocateUntethered(Buffer originator, int size);
/**
* Return memory to the allocator, after it has been untethered from it's lifetime.
* This either happens if the memory has leaked and been re-captured, or if it is no longer in use by a buffer
* through {@link Buffer#ensureWritable(int)}.
*
* @param memory The untethered memory to return to the allocator.
*/
void recoverMemory(Object memory);
/**
* Memory that isn't attached to any particular buffer.
*/
interface UntetheredMemory {
/**
* Produce the recoverable memory object associated with this piece of untethered memory.
* @implNote This method should only be called once, since it might be expensive.
*/
<Memory> Memory memory();
/**
* Produce the drop instance associated with this piece of untethered memory.
* @implNote This method should only be called once, since it might be expensive, or interact with Cleaners.
*/
<BufferType extends Buffer> Drop<BufferType> drop();
}
}