gecko-dev/dom/smil/nsSMILInstanceTime.h

167 lines
6.6 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 NS_SMILINSTANCETIME_H_
#define NS_SMILINSTANCETIME_H_
#include "nsSMILTimeValue.h"
class nsSMILInterval;
class nsSMILTimeContainer;
class nsSMILTimeValueSpec;
//----------------------------------------------------------------------
// nsSMILInstanceTime
//
// An instant in document simple time that may be used in creating a new
// interval.
//
// For an overview of how this class is related to other SMIL time classes see
// the documentation in nsSMILTimeValue.h
//
// These objects are owned by an nsSMILTimedElement but MAY also be referenced
// by:
//
// a) nsSMILIntervals that belong to the same nsSMILTimedElement and which refer
// to the nsSMILInstanceTimes which form the interval endpoints; and/or
// b) nsSMILIntervals that belong to other nsSMILTimedElements but which need to
// update dependent instance times when they change or are deleted.
// E.g. for begin='a.begin', 'a' needs to inform dependent
// nsSMILInstanceTimes if its begin time changes. This notification is
// performed by the nsSMILInterval.
class nsSMILInstanceTime final
{
public:
// Instance time source. Times generated by events, syncbase relationships,
// and DOM calls behave differently in some circumstances such as when a timed
// element is reset.
enum nsSMILInstanceTimeSource {
// No particularly significant source, e.g. offset time, 'indefinite'
SOURCE_NONE,
// Generated by a DOM call such as beginElement
SOURCE_DOM,
// Generated by a syncbase relationship
SOURCE_SYNCBASE,
// Generated by an event
SOURCE_EVENT
};
explicit nsSMILInstanceTime(const nsSMILTimeValue& aTime,
nsSMILInstanceTimeSource aSource = SOURCE_NONE,
nsSMILTimeValueSpec* aCreator = nullptr,
nsSMILInterval* aBaseInterval = nullptr);
void Unlink();
void HandleChangedInterval(const nsSMILTimeContainer* aSrcContainer,
bool aBeginObjectChanged,
bool aEndObjectChanged);
void HandleDeletedInterval();
void HandleFilteredInterval();
const nsSMILTimeValue& Time() const { return mTime; }
const nsSMILTimeValueSpec* GetCreator() const { return mCreator; }
bool IsDynamic() const { return !!(mFlags & kDynamic); }
bool IsFixedTime() const { return !(mFlags & kMayUpdate); }
bool FromDOM() const { return !!(mFlags & kFromDOM); }
bool ShouldPreserve() const;
void UnmarkShouldPreserve();
void AddRefFixedEndpoint();
void ReleaseFixedEndpoint();
void DependentUpdate(const nsSMILTimeValue& aNewTime)
{
MOZ_ASSERT(!IsFixedTime(),
"Updating an instance time that is not expected to be updated");
mTime = aNewTime;
}
bool IsDependent() const { return !!mBaseInterval; }
bool IsDependentOn(const nsSMILInstanceTime& aOther) const;
const nsSMILInterval* GetBaseInterval() const { return mBaseInterval; }
const nsSMILInstanceTime* GetBaseTime() const;
bool SameTimeAndBase(const nsSMILInstanceTime& aOther) const
{
return mTime == aOther.mTime && GetBaseTime() == aOther.GetBaseTime();
}
// Get and set a serial number which may be used by a containing class to
// control the sort order of otherwise similar instance times.
uint32_t Serial() const { return mSerial; }
void SetSerial(uint32_t aIndex) { mSerial = aIndex; }
NS_INLINE_DECL_REFCOUNTING(nsSMILInstanceTime)
private:
// Private destructor, to discourage deletion outside of Release():
~nsSMILInstanceTime();
void SetBaseInterval(nsSMILInterval* aBaseInterval);
nsSMILTimeValue mTime;
// Internal flags used to represent the behaviour of different instance times
enum {
// Indicates that this instance time was generated by an event or a DOM
// call. Such instance times require special handling when (i) the owning
// element is reset, (ii) when they are to be added as a new end instance
// times (as per SMIL's event sensitivity contraints), and (iii) when
// a backwards seek is performed and the timing model is reconstructed.
kDynamic = 1,
// Indicates that this instance time is referred to by an
// nsSMILTimeValueSpec and as such may be updated. Such instance time should
// not be filtered out by the nsSMILTimedElement even if they appear to be
// in the past as they may be updated to a future time.
kMayUpdate = 2,
// Indicates that this instance time was generated from the DOM as opposed
// to an nsSMILTimeValueSpec. When a 'begin' or 'end' attribute is set or
// reset we should clear all the instance times that have been generated by
// that attribute (and hence an nsSMILTimeValueSpec), but not those from the
// DOM.
kFromDOM = 4,
// Indicates that this instance time was used as the endpoint of an interval
// that has been filtered or removed. However, since it is a dynamic time it
// should be preserved and not filtered.
kWasDynamicEndpoint = 8
};
uint8_t mFlags; // Combination of kDynamic, kMayUpdate, etc.
mutable bool mVisited; // Cycle tracking
// Additional reference count to determine if this instance time is currently
// used as a fixed endpoint in any intervals. Instance times that are used in
// this way should not be removed when the owning nsSMILTimedElement removes
// instance times in response to a restart or in an attempt to free up memory
// by filtering out old instance times.
//
// Instance times are only shared in a few cases, namely:
// a) early ends,
// b) zero-duration intervals,
// c) momentarily whilst establishing new intervals and updating the current
// interval, and
// d) trimmed intervals
// Hence the limited range of a uint16_t should be more than adequate.
uint16_t mFixedEndpointRefCnt;
uint32_t mSerial; // A serial number used by the containing class to
// specify the sort order for instance times with the
// same mTime.
nsSMILTimeValueSpec* mCreator; // The nsSMILTimeValueSpec object that created
// us. (currently only needed for syncbase
// instance times.)
nsSMILInterval* mBaseInterval; // Interval from which this time is derived
// (only used for syncbase instance times)
};
#endif // NS_SMILINSTANCETIME_H_