chromium/net/third_party/quiche/src/quiche/http2/core/priority_write_scheduler.h

// Copyright (c) 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef QUICHE_HTTP2_CORE_PRIORITY_WRITE_SCHEDULER_H_
#define QUICHE_HTTP2_CORE_PRIORITY_WRITE_SCHEDULER_H_

#include <algorithm>
#include <cstddef>
#include <cstdint>
#include <memory>
#include <optional>
#include <string>
#include <tuple>
#include <utility>
#include <vector>

#include "absl/container/flat_hash_map.h"
#include "absl/strings/str_cat.h"
#include "absl/time/time.h"
#include "quiche/http2/core/spdy_protocol.h"
#include "quiche/common/platform/api/quiche_bug_tracker.h"
#include "quiche/common/platform/api/quiche_export.h"
#include "quiche/common/platform/api/quiche_logging.h"
#include "quiche/common/quiche_circular_deque.h"

namespace http2 {

namespace test {
template <typename StreamIdType>
class PriorityWriteSchedulerPeer;
}

// SpdyPriority is an integer type, so this functor can be used both as
// PriorityTypeToInt and as IntToPriorityType.
struct QUICHE_EXPORT SpdyPriorityToSpdyPriority { … };

// PriorityWriteScheduler manages the order in which HTTP/2 or HTTP/3 streams
// are written. Each stream has a priority of type PriorityType. This includes
// an integer between 0 and 7, and optionally other information that is stored
// but otherwise ignored by this class.  Higher priority (lower integer value)
// streams are always given precedence over lower priority (higher value)
// streams, as long as the higher priority stream is not blocked.
//
// Each stream can be in one of two states: ready or not ready (for writing).
// Ready state is changed by calling the MarkStreamReady() and
// MarkStreamNotReady() methods. Only streams in the ready state can be returned
// by PopNextReadyStream(). When returned by that method, the stream's state
// changes to not ready.
//
template <typename StreamIdType, typename PriorityType = spdy::SpdyPriority,
          typename PriorityTypeToInt = SpdyPriorityToSpdyPriority,
          typename IntToPriorityType = SpdyPriorityToSpdyPriority>
class QUICHE_EXPORT PriorityWriteScheduler { … };

}  // namespace http2

#endif  // QUICHE_HTTP2_CORE_PRIORITY_WRITE_SCHEDULER_H_