Module io.netty5.buffer

Package io.netty5.buffer.api.bytebuffer

Class ByteBufferMemoryManager

java.lang.Object

io.netty5.buffer.api.bytebuffer.ByteBufferMemoryManager

All Implemented Interfaces:

MemoryManager

public final class ByteBufferMemoryManager
extends Object
implements MemoryManager

This memory manager produces and manages Buffer instances that are backed by NIO ByteBuffer instances.

Memory managers are normally not used directly. Instead, you likely want to use the DefaultBufferAllocators, or the static methods on BufferAllocator.

Constructor Summary

Constructors

Constructor	Description
ByteBufferMemoryManager()

Method Summary

Modifier and Type	Method	Description
Buffer	allocateConstChild(Buffer readOnlyConstParent)	Allocates a constant buffer based on the given parent.
Buffer	allocateShared(AllocatorControl allocatorControl, long size, Function<Drop<Buffer>,Drop<Buffer>> dropDecorator, AllocationType allocationType)	Allocates a shared buffer.
void	clearMemory(Object memory)	Overwrite the given recoverable memory object with zeroes, erasing all data that it contains.
String	implementationName()	Get the name for this implementation, which can be used for finding this particular implementation via the MemoryManager.lookupImplementation(String) method.
Buffer	recoverMemory(AllocatorControl allocatorControl, Object recoverableMemory, Drop<Buffer> drop)	Recover the memory from a prior MemoryManager.unwrapRecoverableMemory(Buffer) call, and wrap it in a Buffer instance.
Object	sliceMemory(Object memory, int offset, int length)	Produces a slice of the given internal memory representation object.
Object	unwrapRecoverableMemory(Buffer buf)	Create an object that represents the internal memory of the given buffer.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ByteBufferMemoryManager

public ByteBufferMemoryManager()

Method Detail

allocateShared

public Buffer allocateShared(AllocatorControl allocatorControl,
                             long size,
                             Function<Drop<Buffer>,Drop<Buffer>> dropDecorator,
                             AllocationType allocationType)

Description copied from interface: MemoryManager

Allocates a shared buffer. "Shared" is the normal type of buffer, and means the buffer permit concurrent access from multiple threads, within the limited thread-safety guarantees of the Buffer interface.

Specified by:

allocateShared in interface MemoryManager

Parameters:

allocatorControl - Call-back interface for controlling the allocator that requested the allocation of this buffer.

size - The size of the buffer to allocate. This size is assumed to be valid for the implementation.

dropDecorator - A function to decorate the memory managers Drop instance. The Drop instance returned by this function will be used when the buffer is closed.

allocationType - The type of allocation to perform. Typically, one of the StandardAllocationTypes.

Returns:

A Buffer instance with the given configuration.

allocateConstChild

public Buffer allocateConstChild(Buffer readOnlyConstParent)

Description copied from interface: MemoryManager

Allocates a constant buffer based on the given parent. A "constant" buffer is conceptually similar to a read-only buffer, but the implementation may share the underlying memory across multiple buffer instance - something that is normally not allowed by the API. This allows efficient implementation of the BufferAllocator.constBufferSupplier(byte[]) method.

Note: The const-parent buffer must be allocated by this memory manager.

Specified by:

allocateConstChild in interface MemoryManager

Parameters:

readOnlyConstParent - The read-only parent buffer for which a const buffer should be created. The parent buffer is allocated in the usual way, with MemoryManager.allocateShared(AllocatorControl, long, Function, AllocationType), initialised with contents, and then made read-only.

Returns:

A const buffer with the same size, contents, and read-only state of the given parent buffer.

unwrapRecoverableMemory

public Object unwrapRecoverableMemory(Buffer buf)

Description copied from interface: MemoryManager

Create an object that represents the internal memory of the given buffer.

Specified by:

unwrapRecoverableMemory in interface MemoryManager

Parameters:

buf - The buffer to unwrap.

Returns:

The internal memory of the given buffer, as an opaque object.

recoverMemory

public Buffer recoverMemory(AllocatorControl allocatorControl,
                            Object recoverableMemory,
                            Drop<Buffer> drop)

Description copied from interface: MemoryManager

Recover the memory from a prior MemoryManager.unwrapRecoverableMemory(Buffer) call, and wrap it in a Buffer instance.

Specified by:

recoverMemory in interface MemoryManager

Parameters:

allocatorControl - The allocator control to attach to the buffer.

recoverableMemory - The opaque memory to use for the buffer.

drop - The Drop instance to use when the buffer is closed.

Returns:

A Buffer instance backed by the given recovered memory.

sliceMemory

public Object sliceMemory(Object memory,
                          int offset,
                          int length)

Description copied from interface: MemoryManager

Produces a slice of the given internal memory representation object.

Specified by:

sliceMemory in interface MemoryManager

Parameters:

memory - The opaque memory to slice.

offset - The offset into the memory to slice from.

length - The length of the slice.

Returns:

A new opaque memory instance that represents the given slice of the original.

clearMemory

public void clearMemory(Object memory)

Description copied from interface: MemoryManager

Overwrite the given recoverable memory object with zeroes, erasing all data that it contains.

This is used by the SensitiveBufferAllocator to erase data on deallocation.

Specified by:

clearMemory in interface MemoryManager

Parameters:

memory - The memory that should be overwritten.

implementationName

public String implementationName()

Description copied from interface: MemoryManager

Get the name for this implementation, which can be used for finding this particular implementation via the MemoryManager.lookupImplementation(String) method.

Specified by:

implementationName in interface MemoryManager

Returns:

The name of this memory managers implementation.