Module org.elasticsearch.nativeaccess

Package org.elasticsearch.nativeaccess.lib

Class ZstdHeapFallback

java.lang.Object

org.elasticsearch.nativeaccess.lib.ZstdHeapFallback

public final class ZstdHeapFallback
extends Object

JDK 21 @Critical fallback for ZstdLibrary.compressHeap(java.lang.foreign.MemorySegment, long, java.lang.foreign.MemorySegment, long, int) / ZstdLibrary.decompressHeap(java.lang.foreign.MemorySegment, long, java.lang.foreign.MemorySegment, long).

On JDK 21 the raw libzstd downcall handle is linked without Linker.Option.critical(true) (the option doesn't exist there), so it rejects heap-backed MemorySegment arguments. The annotation processor wires @Critical(fallbackAdapter = ZstdHeapFallback.class) so that on JDK 21 each compressHeap$mh / decompressHeap$mh field holds an adapter that points at the matching method below: the heap input is staged into a confined Arena, the raw handle is invoked with native segments, and the decoded length is copied back into the caller's heap output. On JDK 22+ this class is not referenced.

Method Summary

Modifier and Type	Method	Description
static long	compressHeap(MethodHandle mh, MemorySegment dst, long dstCap, MemorySegment src, long srcSize, int level)
static long	decompressHeap(MethodHandle mh, MemorySegment dst, long dstCap, MemorySegment src, long srcSize)

Methods inherited from class java.lang.Object

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

Method Details

compressHeap

public static long compressHeap(MethodHandle mh,
 MemorySegment dst,
 long dstCap,
 MemorySegment src,
 long srcSize,
 int level)
                         throws Throwable

Throws:

Throwable

decompressHeap

public static long decompressHeap(MethodHandle mh,
 MemorySegment dst,
 long dstCap,
 MemorySegment src,
 long srcSize)
                           throws Throwable

Throws:

Throwable