com.oracle.svm.core.genscavenge

Class PinnedObjectImpl

java.lang.Object

com.oracle.svm.core.genscavenge.PinnedObjectImpl

All Implemented Interfaces:

AutoCloseable, org.graalvm.nativeimage.PinnedObject

public class PinnedObjectImpl
extends Object
implements org.graalvm.nativeimage.PinnedObject

Holder for a pinned object, such that the object doesn't move until the pin is removed. The garbage collector treats pinned object specially to ensure that they are not moved or discarded.

This class implements AutoCloseable so that the pinning can be managed conveniently with a try-with-resource block that releases the pinning automatically:

   int[] array = ...
   try (PinnedObject pin = PinnedObject.open(array)) {
     CIntPointer rawData = pin.addressOfArrayElement(0);
     // it is safe to pass rawData to a C function.
   }
 

TODO: Is pinning a service of all collectors, or just the one I have now?

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	PinnedObjectImpl(Object object) Constructor.

Method Summary

Modifier and Type	Method and Description
<T extends org.graalvm.word.PointerBase> T	addressOfArrayElement(int index)
org.graalvm.word.Pointer	addressOfObject()
static PinnedObjectImpl	claimPinnedObjectList() Claim the entire list.
void	close() Releases the pin for the object.
PinnedObjectImpl	getNext()
Object	getObject()
boolean	isOpen()
static PinnedObjectImpl	pushPinnedObject(PinnedObjectImpl newHead) Push an element onto the list.
protected void	setNext(PinnedObjectImpl nextPinnedObject)

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.graalvm.nativeimage.PinnedObject

create

Constructor Detail

PinnedObjectImpl

protected PinnedObjectImpl(Object object)

Constructor.

Method Detail

close

public void close()

Releases the pin for the object. After this call, the object can be moved or discarded by the collector.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface org.graalvm.nativeimage.PinnedObject

getObject

public Object getObject()

Specified by:

getObject in interface org.graalvm.nativeimage.PinnedObject

addressOfObject

public org.graalvm.word.Pointer addressOfObject()

Specified by:

addressOfObject in interface org.graalvm.nativeimage.PinnedObject

addressOfArrayElement

public <T extends org.graalvm.word.PointerBase> T addressOfArrayElement(int index)

Specified by:

addressOfArrayElement in interface org.graalvm.nativeimage.PinnedObject

isOpen

public boolean isOpen()

getNext

public PinnedObjectImpl getNext()

setNext

protected void setNext(PinnedObjectImpl nextPinnedObject)

pushPinnedObject

public static PinnedObjectImpl pushPinnedObject(PinnedObjectImpl newHead)

Push an element onto the list. May be called by many threads simultaneously, so it uses a compareAndSet loop.

claimPinnedObjectList

public static PinnedObjectImpl claimPinnedObjectList()

Claim the entire list. Only called once during each collection, but it uses getAndSet(null) anyway so I do not have to worry about it.