Fix refCount issue in LeakAwareDataBuffer

LeakAwareDataBuffer was keeping its own refCount rather than checking
through the delegate. This leads to false leak reports in a sequence
where an allocated buffer is retained and then sliced since it is not
aware of the changes to the refCount through the slice.

spring-core/src/test/java/org/springframework/core/io/buffer/LeakAwareDataBuffer.java

@@ -37,8 +37,6 @@ class LeakAwareDataBuffer implements PooledDataBuffer {
 
 	private final LeakAwareDataBufferFactory dataBufferFactory;
 
-	private int refCount = 1;
-
 
 	LeakAwareDataBuffer(DataBuffer delegate, LeakAwareDataBufferFactory dataBufferFactory) {
 		Assert.notNull(delegate, "Delegate must not be null");
@@ -67,19 +65,24 @@ class LeakAwareDataBuffer implements PooledDataBuffer {
 
 	@Override
 	public boolean isAllocated() {
-		return this.refCount > 0;
+		return this.delegate instanceof PooledDataBuffer &&
+				((PooledDataBuffer) this.delegate).isAllocated();
 	}
 
 	@Override
 	public PooledDataBuffer retain() {
-		this.refCount++;
+		if (this.delegate instanceof PooledDataBuffer) {
+			((PooledDataBuffer) this.delegate).retain();
+		}
 		return this;
 	}
 
 	@Override
 	public boolean release() {
-		this.refCount--;
-		return this.refCount == 0;
+		if (this.delegate instanceof PooledDataBuffer) {
+			((PooledDataBuffer) this.delegate).release();
+		}
+		return isAllocated();
 	}
 
 	// delegation

spring-core/src/test/java/org/springframework/core/io/buffer/LeakAwareDataBufferFactory.java

@@ -99,16 +99,16 @@ public class LeakAwareDataBufferFactory implements DataBufferFactory {
 
 	@Override
 	public DataBuffer allocateBuffer() {
-		return allocateBufferInternal(this.delegate.allocateBuffer());
+		return createLeakAwareDataBuffer(this.delegate.allocateBuffer());
 	}
 
 	@Override
 	public DataBuffer allocateBuffer(int initialCapacity) {
-		return allocateBufferInternal(this.delegate.allocateBuffer(initialCapacity));
+		return createLeakAwareDataBuffer(this.delegate.allocateBuffer(initialCapacity));
 	}
 
 	@NotNull
-	private DataBuffer allocateBufferInternal(DataBuffer delegateBuffer) {
+	private DataBuffer createLeakAwareDataBuffer(DataBuffer delegateBuffer) {
 		LeakAwareDataBuffer dataBuffer = new LeakAwareDataBuffer(delegateBuffer, this);
 		this.created.add(dataBuffer);
 		return dataBuffer;