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/*
* Copyright 2019 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.
*/
#ifndef CALL_ADAPTATION_RESOURCE_H_
#define CALL_ADAPTATION_RESOURCE_H_
#include <string>
#include <vector>
#include "absl/types/optional.h"
#include "api/scoped_refptr.h"
#include "api/task_queue/task_queue_base.h"
#include "call/adaptation/video_source_restrictions.h"
#include "call/adaptation/video_stream_input_state.h"
#include "rtc_base/ref_count.h"
namespace webrtc {
class Resource;
enum class ResourceUsageState {
// Action is needed to minimze the load on this resource.
kOveruse,
// Increasing the load on this resource is desired, if possible.
kUnderuse,
};
const char* ResourceUsageStateToString(ResourceUsageState usage_state);
class ResourceListener {
public:
virtual ~ResourceListener();
// Informs the listener of a new measurement of resource usage. This means
// that |resource->usage_state()| is now up-to-date.
virtual void OnResourceUsageStateMeasured(
rtc::scoped_refptr<Resource> resource) = 0;
};
// A Resource monitors an implementation-specific system resource. It may report
// kOveruse or kUnderuse when resource usage is high or low enough that we
// should perform some sort of mitigation to fulfil the resource's constraints.
//
// All methods defined in this interface, except RegisterAdaptationTaskQueue(),
// MUST be invoked on the resource adaptation task queue.
//
// Usage measurements may be performed on an implementation-specific task queue.
// The Resource is reference counted to prevent use-after-free when posting
// between task queues. As such, the implementation MUST NOT make any
// assumptions about which task queue Resource is destructed on.
class Resource : public rtc::RefCountInterface {
public:
Resource();
// Destruction may happen on any task queue.
~Resource() override;
// Provides a pointer to the adaptation task queue. After this call, all
// methods defined in this interface, including
// UnregisterAdaptationTaskQueue() MUST be invoked on the adaptation task
// queue. Registering the adaptation task queue may, however, happen off the
// adaptation task queue.
virtual void RegisterAdaptationTaskQueue(
TaskQueueBase* resource_adaptation_queue) = 0;
// Signals that the adaptation task queue is no longer safe to use. No
// assumptions must be made as to whether or not tasks in-flight will run.
virtual void UnregisterAdaptationTaskQueue() = 0;
// The listeners MUST be informed any time UsageState() changes.
virtual void SetResourceListener(ResourceListener* listener) = 0;
virtual std::string Name() const = 0;
// Within a single task running on the adaptation task queue, UsageState()
// MUST return the same value every time it is called.
// TODO(https://crbug.com/webrtc/11618): Remove the UsageState() getter in
// favor of passing the use usage state directly to the ResourceListener. This
// gets rid of this strange requirement of having to return the same thing
// every time.
virtual absl::optional<ResourceUsageState> UsageState() const = 0;
// Invalidates current usage measurements, i.e. in response to the system load
// changing. Example: an adaptation was just applied.
virtual void ClearUsageState() = 0;
// This method allows the Resource to reject a proposed adaptation in the "up"
// direction if it predicts this would cause overuse of this resource.
virtual bool IsAdaptationUpAllowed(
const VideoStreamInputState& input_state,
const VideoSourceRestrictions& restrictions_before,
const VideoSourceRestrictions& restrictions_after,
rtc::scoped_refptr<Resource> reason_resource) const = 0;
virtual void OnAdaptationApplied(
const VideoStreamInputState& input_state,
const VideoSourceRestrictions& restrictions_before,
const VideoSourceRestrictions& restrictions_after,
rtc::scoped_refptr<Resource> reason_resource) = 0;
};
} // namespace webrtc
#endif // CALL_ADAPTATION_RESOURCE_H_
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