chromium/third_party/dawn/src/dawn/native/EventManager.h

// Copyright 2023 The Dawn & Tint Authors
//
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// modification, are permitted provided that the following conditions are met:
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//    this list of conditions and the following disclaimer in the documentation
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#ifndef SRC_DAWN_NATIVE_EVENTMANAGER_H_
#define SRC_DAWN_NATIVE_EVENTMANAGER_H_

#include <atomic>
#include <cstdint>
#include <mutex>
#include <optional>
#include <variant>

#include "absl/container/flat_hash_map.h"
#include "dawn/common/FutureUtils.h"
#include "dawn/common/MutexProtected.h"
#include "dawn/common/NonMovable.h"
#include "dawn/common/Ref.h"
#include "dawn/native/Error.h"
#include "dawn/native/Forward.h"
#include "dawn/native/IntegerTypes.h"
#include "dawn/native/SystemEvent.h"

namespace dawn::native {

struct InstanceDescriptor;

// Subcomponent of the Instance which tracks callback events for the Future-based callback
// entrypoints. All events from this instance (regardless of whether from an adapter, device, queue,
// etc.) are tracked here, and used by the instance-wide ProcessEvents and WaitAny entrypoints.
//
// TODO(crbug.com/dawn/2050): Can this eventually replace CallbackTaskManager?
//
// There are various ways to optimize ProcessEvents/WaitAny:
// - TODO(crbug.com/dawn/2059) Spontaneously set events as "early-ready" in other places when we see
//   serials advance, e.g. Submit, or when checking a later wait before an earlier wait.
class EventManager final : NonMovable { … };

struct QueueAndSerial { … };

// Base class for the objects that back WGPUFutures. TrackedEvent is responsible for the lifetime
// the callback it contains. If TrackedEvent gets destroyed before it completes, it's responsible
// for cleaning up (by calling the callback with an "Unknown" status).
//
// For Future-based and ProcessEvents-based TrackedEvents, the EventManager will track them for
// completion in WaitAny or ProcessEvents. However, once the Instance has lost all its external
// refs, the user can't call either of those methods anymore, so EventManager will stop holding refs
// to any TrackedEvents. Any which are not ref'd elsewhere (in order to be `Spontaneous`ly
// completed) will be cleaned up at that time.
class EventManager::TrackedEvent : public RefCounted { … };

}  // namespace dawn::native

#endif  // SRC_DAWN_NATIVE_EVENTMANAGER_H_