Package io.netty.util.internal

Class CleanerJava24Linker

java.lang.Object

io.netty.util.internal.CleanerJava24Linker

All Implemented Interfaces:

Cleaner

public class CleanerJava24Linker
extends java.lang.Object
implements Cleaner

Allocates direct buffers with malloc and free from libc, linked through the Foreign Function & Memory API.

The FFM API is compiled against the netty-ffm-stub module. It and the signature-polymorphic MethodHandle calls are only used from the nested classes, which are only loaded on Java versions that have the FFM API, so this class still loads and verifies where it is missing (e.g. Android).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private static class	CleanerJava24Linker.CleanableDirectBufferImpl
private static class	CleanerJava24Linker.Holder	Links malloc and free on first use rather than when PlatformDependent is initialized, because creating the downcall handles is a startup cost for applications that may never allocate a direct buffer.
private static class	CleanerJava24Linker.Symbols	Checks that native access is enabled for this module, and that this platform has a 64-bit native linker that finds malloc and free.

Field Summary

Fields

Modifier and Type	Field	Description
private static InternalLogger	logger
private static boolean	SUPPORTED

Constructor Summary

Constructors

Constructor	Description
CleanerJava24Linker()

Method Summary

Modifier and Type	Method	Description
CleanableDirectBuffer	allocate(int capacity)	Create a direct ByteBuffer and return it alongside its cleaning mechanism, in a CleanableDirectBuffer.
(package private) static void	free(long memoryAddress)
void	freeDirectBuffer(java.nio.ByteBuffer buffer)	Free a direct ByteBuffer if possible
boolean	hasExpensiveClean()	Check if the clean operation is "relatively expensive".
(package private) static boolean	isSupported()
(package private) static long	malloc(int capacity)

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.netty.util.internal.Cleaner

reallocate

Field Detail

logger

private static final InternalLogger logger

SUPPORTED

private static final boolean SUPPORTED

Constructor Detail

CleanerJava24Linker

public CleanerJava24Linker()

Method Detail

isSupported

static boolean isSupported()

allocate

public CleanableDirectBuffer allocate(int capacity)

Description copied from interface: Cleaner

Create a direct ByteBuffer and return it alongside its cleaning mechanism, in a CleanableDirectBuffer.

Specified by:

allocate in interface Cleaner

Parameters:

capacity - The desired capacity of the direct buffer.

Returns:

The new CleanableDirectBuffer instance.

freeDirectBuffer

public void freeDirectBuffer(java.nio.ByteBuffer buffer)

Description copied from interface: Cleaner

Free a direct ByteBuffer if possible

Specified by:

freeDirectBuffer in interface Cleaner

hasExpensiveClean

public boolean hasExpensiveClean()

Description copied from interface: Cleaner

Check if the clean operation is "relatively expensive". Expensive clean operations are fine for pooling allocators, but should be avoided for unpooled buffers.

Specified by:

hasExpensiveClean in interface Cleaner

Returns:

true if this Cleaner has an expensive clean (i.e. CleanableDirectBuffer.clean()) operation.

malloc

static long malloc(int capacity)

free

static void free(long memoryAddress)