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// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef THIRD_PARTY_BLINK_RENDERER_MODULES_PEERCONNECTION_RTP_CONTRIBUTING_SOURCE_CACHE_H_
#define THIRD_PARTY_BLINK_RENDERER_MODULES_PEERCONNECTION_RTP_CONTRIBUTING_SOURCE_CACHE_H_
#include <utility>
#include <vector>
#include "base/memory/scoped_refptr.h"
#include "base/memory/weak_ptr.h"
#include "base/synchronization/waitable_event.h"
#include "base/task/single_thread_task_runner.h"
#include "third_party/blink/renderer/bindings/modules/v8/v8_rtc_rtp_contributing_source.h"
#include "third_party/blink/renderer/bindings/modules/v8/v8_rtc_rtp_synchronization_source.h"
#include "third_party/blink/renderer/modules/peerconnection/rtc_rtp_receiver.h"
#include "third_party/blink/renderer/platform/heap/collection_support/heap_vector.h"
#include "third_party/blink/renderer/platform/heap/persistent.h"
#include "third_party/blink/renderer/platform/peerconnection/rtc_rtp_source.h"
#include "third_party/blink/renderer/platform/wtf/hash_map.h"
#include "third_party/blink/renderer/platform/wtf/vector.h"
namespace blink {
class RTCPeerConnection;
class ScriptState;
// Implements RTCRtpReceiver.getSynchronizationSources/getContributingSources as
// well as a cache of the result. The cache serves two purposes:
// 1. According to spec, calling the getters multiple times inside the same task
// execution cycle must return the same values. The cache is cleared in the
// next microtask.
// 2. Getting the SSRC/CSRC values involves a block-invoke to the WebRTC worker
// thread. This class uses a heuristic to maybe-update the cache for all
// RTCRtpReceiver objects inside the same block-invoke, reducing the total
// number of block-invokes if the getters are called on every RTCRtpReceiver.
class RtpContributingSourceCache {
public:
typedef Vector<std::unique_ptr<RTCRtpSource>> RTCRtpSources;
RtpContributingSourceCache(
RTCPeerConnection* pc,
scoped_refptr<base::SingleThreadTaskRunner> worker_thread_runner);
// When the owner of this object is Disposed(), this method must be called to
// cancel any in-flight tasks.
void Shutdown();
HeapVector<Member<RTCRtpSynchronizationSource>> getSynchronizationSources(
ScriptState* script_state,
ExceptionState& exception_state,
RTCRtpReceiver* receiver);
HeapVector<Member<RTCRtpContributingSource>> getContributingSources(
ScriptState* script_state,
ExceptionState& exception_state,
RTCRtpReceiver* receiver);
private:
// Ensures the cache for `requesting_receiver` is up-to-date. Based on a
// heuristic, this method may update the cache for all other receivers while
// it is at it.
void MaybeUpdateRtpSources(ScriptState* script_state,
RTCRtpReceiver* requesting_receiver);
void UpdateRtpSourcesOnWorkerThread(
Vector<RTCRtpReceiverPlatform*>* receivers,
HashMap<RTCRtpReceiverPlatform*, RTCRtpSources>*
cached_sources_by_receiver,
base::WaitableEvent* event);
void ClearCache();
const RTCRtpSources* GetRtpSources(RTCRtpReceiver* receiver) const;
// Owner of all RTCRtpReceiver objects that this cache is concerned with.
const WeakPersistent<RTCPeerConnection> pc_;
const scoped_refptr<base::SingleThreadTaskRunner> worker_thread_runner_;
// We cache audio and video receivers separately in case the app is only
// interested in one of the kinds. Having a small fixed number of audio
// receivers where audio levels are polled and a large number of video
// receivers that are not being polled is a common setup.
HashMap<RTCRtpReceiverPlatform*, RTCRtpSources>
cached_sources_by_audio_receiver_;
HashMap<RTCRtpReceiverPlatform*, RTCRtpSources>
cached_sources_by_video_receiver_;
base::WeakPtrFactory<RtpContributingSourceCache> weak_factory_{this};
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_MODULES_PEERCONNECTION_RTP_CONTRIBUTING_SOURCE_CACHE_H_
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