content/browser/background_fetch/background_fetch_registration_notifier.h

// Copyright 2017 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 CONTENT_BROWSER_BACKGROUND_FETCH_BACKGROUND_FETCH_REGISTRATION_NOTIFIER_H_
#define CONTENT_BROWSER_BACKGROUND_FETCH_BACKGROUND_FETCH_REGISTRATION_NOTIFIER_H_

#include <stdint.h>
#include <map>
#include <string>

#include "base/callback.h"
#include "base/macros.h"
#include "base/memory/weak_ptr.h"
#include "content/common/content_export.h"
#include "third_party/WebKit/public/platform/modules/background_fetch/background_fetch.mojom.h"

namespace content {

// Tracks the live BackgroundFetchRegistration objects across the renderer
// processes and provides the functionality to notify them of progress updates.
class CONTENT_EXPORT BackgroundFetchRegistrationNotifier {
 public:
  BackgroundFetchRegistrationNotifier();
  ~BackgroundFetchRegistrationNotifier();

  // Registers the |observer| to be notified when fetches for the registration
  // identified by the |unique_id| progress.
  void AddObserver(
      const std::string& unique_id,
      blink::mojom::BackgroundFetchRegistrationObserverPtr observer);

  // Notifies any registered observers for the registration identified by the
  // |unique_id| of the progress. This will cause JavaScript events to fire.
  // Successful fetches must also call Notify with the final state.
  void Notify(const std::string& unique_id,
              uint64_t download_total,
              uint64_t downloaded);

  // Runs |callback| when the last observer for |unique_id| is removed, or
  // immediately if there are already no observers. Callback will never be run
  // if the browser is shutdown before the last observer is removed.
  void AddGarbageCollectionCallback(const std::string& unique_id,
                                    base::OnceClosure callback);

  base::WeakPtr<BackgroundFetchRegistrationNotifier> GetWeakPtr() {
    return weak_factory_.GetWeakPtr();
  }

 private:
  // Called when the connection with the |observer| for the registration
  // identified by the |unique_id| goes away.
  void OnConnectionError(
      const std::string& unique_id,
      blink::mojom::BackgroundFetchRegistrationObserver* observer);

  // Storage of observers keyed by the |unique_id| of a registration.
  std::multimap<std::string,
                blink::mojom::BackgroundFetchRegistrationObserverPtr>
      observers_;

  // Map from registration |unique_id| to callback to run when last observer is
  // removed.
  std::map<std::string, base::OnceClosure> garbage_collection_callbacks_;

  base::WeakPtrFactory<BackgroundFetchRegistrationNotifier> weak_factory_;

  DISALLOW_COPY_AND_ASSIGN(BackgroundFetchRegistrationNotifier);
};

}  // namespace content

#endif  // CONTENT_BROWSER_BACKGROUND_FETCH_BACKGROUND_FETCH_REGISTRATION_NOTIFIER_H_