gecko-dev/dom/base/Timeout.h

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim:set ts=2 sw=2 sts=2 et cindent: */
/* 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/. */

#ifndef mozilla_dom_timeout_h
#define mozilla_dom_timeout_h

#include "mozilla/LinkedList.h"
#include "mozilla/TimeStamp.h"
#include "nsCOMPtr.h"
#include "nsCycleCollectionParticipant.h"

class nsGlobalWindow;
class nsIEventTarget;
class nsIPrincipal;
class nsITimeoutHandler;
class nsITimer;
class nsIEventTarget;

namespace mozilla {
namespace dom {

/*
 * Timeout struct that holds information about each script
 * timeout.  Holds a strong reference to an nsITimeoutHandler, which
 * abstracts the language specific cruft.
 */
class Timeout final
  : public LinkedListElement<RefPtr<Timeout>>
{
public:
  Timeout();

  NS_DECL_CYCLE_COLLECTION_NATIVE_CLASS(Timeout)
  NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(Timeout)

  // The target may be specified to use a particular event queue for the
  // resulting timer runnable.  A nullptr target will result in the
  // default main thread being used.
  nsresult InitTimer(nsIEventTarget* aTarget, uint32_t aDelay);

  void MaybeCancelTimer();

  enum class Reason
  {
    eTimeoutOrInterval,
    eIdleCallbackTimeout,
  };

  void SetWhenOrTimeRemaining(const TimeStamp& aBaseTime,
                              const TimeDuration& aDelay);

  void SetDummyWhen(const TimeStamp& aWhen);

  // Can only be called when not frozen.
  const TimeStamp& When() const;

  // Can only be called when frozen.
  const TimeDuration& TimeRemaining() const;

  // Can only be called when not frozen.
  const TimeDuration& ScheduledDelay() const;

  // Window for which this timeout fires
  RefPtr<nsGlobalWindow> mWindow;

  // The actual timer object
  nsCOMPtr<nsITimer> mTimer;

  // True if the timeout was cleared
  bool mCleared;

  // True if this is one of the timeouts that are currently running
  bool mRunning;

  // True if this is a repeating/interval timer
  bool mIsInterval;

  // True if this is a timeout coming from a tracking script
  bool mIsTracking;

  // Used to allow several reasons for setting a timeout, where each
  // 'Reason' value is using a possibly overlapping set of id:s.
  Reason mReason;

  // Returned as value of setTimeout()
  uint32_t mTimeoutId;

  // Interval in milliseconds
  uint32_t mInterval;

  // Identifies which firing level this Timeout is being processed in
  // when sync loops trigger nested firing.
  uint32_t mFiringId;

  uint32_t mNestingLevel;

  // The popup state at timeout creation time if not created from
  // another timeout
  PopupControlState mPopupState;

  // The language-specific information about the callback.
  nsCOMPtr<nsITimeoutHandler> mScriptHandler;

  RefPtr<Timeout> mClosureSelfRef;

private:
  // mWhen and mTimeRemaining can't be in a union, sadly, because they
  // have constructors.
  // Nominal time to run this timeout.  Use only when timeouts are not
  // frozen.
  TimeStamp mWhen;

  // Remaining time to wait.  Used only when timeouts are frozen.
  TimeDuration mTimeRemaining;

  // The actual interval in milliseconds.  This may be throttled to
  // a longer delay than mInterval for a number of reasons.
  TimeDuration mScheduledDelay;

  ~Timeout();
};

} // namespace dom
} // namespace mozilla

#endif // mozilla_dom_timeout_h