chromium/extensions/browser/updater/request_queue.h

// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef EXTENSIONS_BROWSER_UPDATER_REQUEST_QUEUE_H_
#define EXTENSIONS_BROWSER_UPDATER_REQUEST_QUEUE_H_

#include <stddef.h>

#include <memory>
#include <optional>
#include <utility>

#include "base/containers/circular_deque.h"
#include "base/functional/callback.h"
#include "base/memory/raw_ptr.h"
#include "base/time/time.h"
#include "base/timer/timer.h"
#include "net/base/backoff_entry.h"

namespace extensions {

// This class keeps track of a queue of requests, and contains the logic to
// retry requests with some backoff policy. Each request has a
// net::BackoffEntry instance associated with it.
//
// The general flow when using this class would be something like this:
//   - requests are queued up by calling ScheduleRequest.
//   - when a request is ready to be executed, RequestQueue removes the
//     request from the queue, assigns it as active request, and calls
//     the callback that was passed to the constructor.
//   - (optionally) when a request has completed unsuccessfully call
//     RetryRequest to put the request back in the queue, using the
//     backoff policy and minimum backoff delay to determine when to
//     next schedule this request.
//   - call reset_active_request() to indicate that the active request has
//     been dealt with.
//   - call StartNextRequest to schedule the next pending request (if any).
template <typename T>
class RequestQueue { … };

// Iterator class that wraps a base::circular_deque<> iterator, only giving
// access to the actual request part of each item.
template <typename T>
class RequestQueue<T>::iterator { … };

}  // namespace extensions

#endif  // EXTENSIONS_BROWSER_UPDATER_REQUEST_QUEUE_H_