gecko-dev/dom/webidl/PermissionStatus.webidl
Andrea Marchesini 8ae9152b88 Bug 1193373 - Support Permissions API in Worker Context, r=manuel,webidl,asuth,smaug
This commit exposes the Permissions API to DOM Workers. It achieves this goal
by introducing a thread-safe bridge between `PermissionStatus` and the
`PermissionObserver`: the `PermissionStatusSink` object.

Actors:
- The `PermissionObserver` is a main-thread-only singleton that monitors
  permission change events and propagates the notification to the right sink
  objects.
- The `PermissionStatus` is the DOM object exposed to the global. It's not
  thread-safe.
- The `PermissionStatusSink` is the new bridge introduced by this commit.

The `PermissionStatusSink` lifetime:
- This object is kept alive on the current thread by the `PermissionStatus` and
  on the main thread by the `PermissionObserver`.
- The `PermissionStatus` creates the object on its creation thread. When
  `PermissionStatus` object is released (or disconnected from the owner, it
  disentangles itself from the `PermissionStatusSink`. The disentangle
  operation triggers the un-registration procedure from the
  `PermissionObserver` on the main thread.
- A weak `WorkerRef` is used to monitor the worker's lifetime.

Permission change notification:
- When the  `PermissionObserver` is notified for a permission-change event, it
  notifies all the `PermissionStatusSink`. This happens on the main thread (see
  `MaybeUpdatedByOnMainThread` and `MaybeUpdatedByNotifyOnlyOnMainThread`).
- Using `MozPromise`, the `PermissionStatusSink` computes the permission action
  (`PermissionChangedOnMainThread`) on the main thread, then informs the
  parent `PermissionStatus` object on its creation thread.
- The `PermissionStatus` object converts the action to the DOM
  `PermissionState` and dispatches an event.

Differential Revision: https://phabricator.services.mozilla.com/D224594
2024-10-11 06:53:48 +00:00

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/* -*- Mode: IDL; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
* You can obtain one at http://mozilla.org/MPL/2.0/.
*
* The origin of this IDL file is
* https://w3c.github.io/permissions/#status-of-a-permission
*/
enum PermissionState {
"granted",
"denied",
"prompt"
};
[Exposed=(Window,Worker)]
interface PermissionStatus : EventTarget {
readonly attribute PermissionName name;
readonly attribute PermissionState state;
attribute EventHandler onchange;
[ChromeOnly]
readonly attribute UTF8String type;
};