io.humble.ferry

Class JNIMemoryAllocator

java.lang.Object

io.humble.ferry.JNIMemoryAllocator

public final class JNIMemoryAllocator
extends Object

Internal Only.

This object allocates large memory chunks and returns them to native code. The native memory then pins raw bytes based on the byte[]s returned here. The net effect is that Java ends up thinking it actually allocated the memory, but since a RefCounted object will also maintain a reference to this allocator, you can use this to detect instances of 'leaked' references in your Java code.

This function is called DIRECTLY from native code; names of methods MUST NOT CHANGE.

Author:

aclarke

Method Summary

Modifier and Type	Method and Description
void	free(byte[] mem) Free memory allocated by the malloc(int) method.
static JNIMemoryAllocator	getAllocator(long nativeObj) Internal Only.
byte[]	malloc(int size) Internal Only.
static void	setAllocator(long nativeObj, JNIMemoryAllocator mgr) Internal Only.

Methods inherited from class java.lang.Object

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

Method Detail

malloc

public byte[] malloc(int size)

Internal Only. Allocate a new block of bytes. Called from native code.

Will retry many times if it can't get memory, backing off in timeouts to get there.

Callers must eventually call free(byte[]) when done with the bytes or a leak will result.

Parameters:

size - # of bytes requested

Returns:

An array of size or more bytes long, or null on failure.

free

public void free(byte[] mem)

Free memory allocated by the malloc(int) method. Called from native code.

Parameters:

mem - the byes to be freed.

setAllocator

public static void setAllocator(long nativeObj,
                                JNIMemoryAllocator mgr)

Internal Only. Native method that tells a native objects (represented by the nativeObj long pointer val) that this JNIMemoryAllocator is being used to allocate it's large blocks of memory.

Follow that? No. That's OK... you really don't want to know.

Parameters:

nativeObj - A C pointer (a la swig).

mgr - Us.

getAllocator

public static JNIMemoryAllocator getAllocator(long nativeObj)

Internal Only. Get the allocator for the underlying native pointer.

Parameters:

nativeObj - The native pointer.

Returns:

The allocator to use, or null.