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/* -*- 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 */
#include "nsISupportsImpl.h"
#include "mozilla/SMILTimeValue.h"
namespace mozilla {
class SMILInterval;
class SMILTimeContainer;
class SMILTimeValueSpec;
// SMILInstanceTime
// 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 SMILTimeValue.h
// These objects are owned by an SMILTimedElement but MAY also be referenced
// by:
// a) SMILIntervals that belong to the same SMILTimedElement and which refer
// to the SMILInstanceTimes which form the interval endpoints; and/or
// b) SMILIntervals that belong to other SMILTimedElements 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
// SMILInstanceTimes if its begin time changes. This notification is
// performed by the SMILInterval.
class SMILInstanceTime final {
// 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 SMILInstanceTimeSource {
// No particularly significant source, e.g. offset time, 'indefinite'
// Generated by a DOM call such as beginElement
// Generated by a syncbase relationship
// Generated by an event
explicit SMILInstanceTime(const SMILTimeValue& aTime,
SMILInstanceTimeSource aSource = SOURCE_NONE,
SMILTimeValueSpec* aCreator = nullptr,
SMILInterval* aBaseInterval = nullptr);
void Unlink();
void HandleChangedInterval(const SMILTimeContainer* aSrcContainer,
bool aBeginObjectChanged, bool aEndObjectChanged);
void HandleDeletedInterval();
void HandleFilteredInterval();
const SMILTimeValue& Time() const { return mTime; }
const SMILTimeValueSpec* 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 SMILTimeValue& aNewTime) {
"Updating an instance time that is not expected to be updated");
mTime = aNewTime;
bool IsDependent() const { return !!mBaseInterval; }
bool IsDependentOn(const SMILInstanceTime& aOther) const;
const SMILInterval* GetBaseInterval() const { return mBaseInterval; }
const SMILInstanceTime* GetBaseTime() const;
bool SameTimeAndBase(const SMILInstanceTime& 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; }
// Private destructor, to discourage deletion outside of Release():
void SetBaseInterval(SMILInterval* aBaseInterval);
SMILTimeValue 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
// SMILTimeValueSpec and as such may be updated. Such instance time should
// not be filtered out by the SMILTimedElement 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 SMILTimeValueSpec. 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 SMILTimeValueSpec), 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 SMILTimedElement 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.
SMILTimeValueSpec* mCreator; // The SMILTimeValueSpec object that created
// us. (currently only needed for syncbase
// instance times.)
SMILInterval* mBaseInterval; // Interval from which this time is derived
// (only used for syncbase instance times)
} // namespace mozilla