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/*
* Copyright 2018 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
package org.webrtc;
import androidx.annotation.Nullable;
import java.util.concurrent.atomic.AtomicInteger;
/**
* Implementation of RefCounted that executes a Runnable once the ref count reaches zero.
*/
class RefCountDelegate implements RefCounted {
private final AtomicInteger refCount = new AtomicInteger(1);
private final @Nullable Runnable releaseCallback;
/**
* @param releaseCallback Callback that will be executed once the ref count reaches zero.
*/
public RefCountDelegate(@Nullable Runnable releaseCallback) {
this.releaseCallback = releaseCallback;
}
@Override
public void retain() {
int updated_count = refCount.incrementAndGet();
if (updated_count < 2) {
throw new IllegalStateException("retain() called on an object with refcount < 1");
}
}
@Override
public void release() {
int updated_count = refCount.decrementAndGet();
if (updated_count < 0) {
throw new IllegalStateException("release() called on an object with refcount < 1");
}
if (updated_count == 0 && releaseCallback != null) {
releaseCallback.run();
}
}
/**
* Tries to retain the object. Can be used in scenarios where it is unknown if the object has
* already been released. Returns true if successful or false if the object was already released.
*/
boolean safeRetain() {
int currentRefCount = refCount.get();
while (currentRefCount != 0) {
if (refCount.weakCompareAndSet(currentRefCount, currentRefCount + 1)) {
return true;
}
currentRefCount = refCount.get();
}
return false;
}
}