0f6bcd18b2
This makes it safe to deliver frames to the sink from VideoProcessor even after setSink has been called with null reference without danger of use after free. Bug: b/148063550 Change-Id: Ib78f75ac49fc6117f744c55da1a4e671bbdcdf22 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/168160 Reviewed-by: Paulina Hensman <phensman@webrtc.org> Commit-Queue: Sami Kalliomäki <sakal@webrtc.org> Cr-Commit-Position: refs/heads/master@{#30455}
64 lines
2.0 KiB
Java
64 lines
2.0 KiB
Java
/*
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* Copyright 2018 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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package org.webrtc;
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import android.support.annotation.Nullable;
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import java.util.concurrent.atomic.AtomicInteger;
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/**
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* Implementation of RefCounted that executes a Runnable once the ref count reaches zero.
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*/
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class RefCountDelegate implements RefCounted {
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private final AtomicInteger refCount = new AtomicInteger(1);
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private final @Nullable Runnable releaseCallback;
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/**
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* @param releaseCallback Callback that will be executed once the ref count reaches zero.
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*/
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public RefCountDelegate(@Nullable Runnable releaseCallback) {
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this.releaseCallback = releaseCallback;
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}
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@Override
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public void retain() {
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int updated_count = refCount.incrementAndGet();
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if (updated_count < 2) {
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throw new IllegalStateException("retain() called on an object with refcount < 1");
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}
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}
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@Override
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public void release() {
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int updated_count = refCount.decrementAndGet();
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if (updated_count < 0) {
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throw new IllegalStateException("release() called on an object with refcount < 1");
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}
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if (updated_count == 0 && releaseCallback != null) {
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releaseCallback.run();
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}
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}
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/**
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* Tries to retain the object. Can be used in scenarios where it is unknown if the object has
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* already been released. Returns true if successful or false if the object was already released.
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*/
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boolean safeRetain() {
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int currentRefCount = refCount.get();
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while (currentRefCount != 0) {
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if (refCount.weakCompareAndSet(currentRefCount, currentRefCount + 1)) {
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return true;
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}
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currentRefCount = refCount.get();
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}
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return false;
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}
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}
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