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WakeLockSentinel.h (2140B)

      1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim:set ts=2 sw=2 sts=2 et cindent: */
      3 /* This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #ifndef DOM_WAKELOCKSENTINEL_H_
      8 #define DOM_WAKELOCKSENTINEL_H_
      9 
     10 #include "js/TypeDecls.h"
     11 #include "mozilla/Attributes.h"
     12 #include "mozilla/DOMEventTargetHelper.h"
     13 #include "mozilla/TimeStamp.h"
     14 #include "mozilla/dom/WakeLockBinding.h"
     15 
     16 namespace mozilla::dom {
     17 
     18 class Promise;
     19 
     20 }  // namespace mozilla::dom
     21 
     22 namespace mozilla::dom {
     23 
     24 class WakeLockSentinel final : public DOMEventTargetHelper {
     25 public:
     26  WakeLockSentinel(nsIGlobalObject* aOwnerWindow, WakeLockType aType)
     27      : DOMEventTargetHelper(aOwnerWindow),
     28        mType(aType),
     29        mCreationTime(TimeStamp::Now()) {}
     30 
     31 protected:
     32  ~WakeLockSentinel() {
     33    MOZ_DIAGNOSTIC_ASSERT(mReleased);
     34    MOZ_DIAGNOSTIC_ASSERT(!mHoldsActualLock);
     35  }
     36 
     37 public:
     38  JSObject* WrapObject(JSContext* aCx,
     39                       JS::Handle<JSObject*> aGivenProto) override;
     40 
     41  bool Released() const;
     42 
     43  WakeLockType Type() const { return mType; }
     44 
     45  MOZ_CAN_RUN_SCRIPT
     46  already_AddRefed<Promise> ReleaseLock(ErrorResult& aRv);
     47 
     48  MOZ_CAN_RUN_SCRIPT
     49  void NotifyLockReleased();
     50 
     51  IMPL_EVENT_HANDLER(release);
     52 
     53  // Acquire underlying system wake lock by modifying the HAL wake lock counter
     54  void AcquireActualLock();
     55 
     56 private:
     57  WakeLockType mType;
     58 
     59  bool mReleased = false;
     60 
     61  /**
     62   * To avoid user fingerprinting, WakeLockJS::Request will provide a
     63   * WakeLockSentinel even if the lock type is not applicable or cannot be
     64   * obtained.
     65   * But when releasing this sentinel, we have to know whether
     66   * AcquireActualLock was called.
     67   *
     68   * https://w3c.github.io/screen-wake-lock/#dfn-applicable-wake-lock
     69   * https://w3c.github.io/screen-wake-lock/#the-request-method
     70   */
     71  bool mHoldsActualLock = false;
     72 
     73  // Time when this object was created
     74  TimeStamp mCreationTime;
     75 };
     76 
     77 }  // namespace mozilla::dom
     78 
     79 #endif  // DOM_WAKELOCKSENTINEL_H_