michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef NS_SMILMILESTONE_H_
michael@0: #define NS_SMILMILESTONE_H_
michael@0: 
michael@0: /*
michael@0:  * A significant moment in an nsSMILTimedElement's lifetime where a sample is
michael@0:  * required.
michael@0:  *
michael@0:  * Animations register the next milestone in their lifetime with the time
michael@0:  * container that they belong to. When the animation controller goes to run
michael@0:  * a sample it first visits all the animations that have a registered milestone
michael@0:  * in order of their milestone times. This allows interdependencies between
michael@0:  * animations to be correctly resolved and events to fire in the proper order.
michael@0:  *
michael@0:  * A distinction is made between a milestone representing the end of an interval
michael@0:  * and any other milestone. This is because if animation A ends at time t, and
michael@0:  * animation B begins at the same time t (or has some other significant moment
michael@0:  * such as firing a repeat event), SMIL's endpoint-exclusive timing model
michael@0:  * implies that the interval end occurs first. In fact, interval ends can be
michael@0:  * thought of as ending an infinitesimally small time before t. Therefore,
michael@0:  * A should be sampled before B.
michael@0:  *
michael@0:  * Furthermore, this distinction between sampling the end of an interval and
michael@0:  * a regular sample is used within the timing model (specifically in
michael@0:  * nsSMILTimedElement) to ensure that all intervals ending at time t are sampled
michael@0:  * before any new intervals are entered so that we have a fully up-to-date set
michael@0:  * of instance times available before committing to a new interval. Once an
michael@0:  * interval is entered, the begin time is fixed.
michael@0:  */
michael@0: class nsSMILMilestone
michael@0: {
michael@0: public:
michael@0:   nsSMILMilestone(nsSMILTime aTime, bool aIsEnd)
michael@0:     : mTime(aTime), mIsEnd(aIsEnd)
michael@0:   { }
michael@0: 
michael@0:   nsSMILMilestone()
michael@0:     : mTime(0), mIsEnd(false)
michael@0:   { }
michael@0: 
michael@0:   bool operator==(const nsSMILMilestone& aOther) const
michael@0:   {
michael@0:     return mTime == aOther.mTime && mIsEnd == aOther.mIsEnd;
michael@0:   }
michael@0: 
michael@0:   bool operator!=(const nsSMILMilestone& aOther) const
michael@0:   {
michael@0:     return !(*this == aOther);
michael@0:   }
michael@0: 
michael@0:   bool operator<(const nsSMILMilestone& aOther) const
michael@0:   {
michael@0:     // Earlier times sort first, and for equal times end milestones sort first
michael@0:     return mTime < aOther.mTime ||
michael@0:           (mTime == aOther.mTime && mIsEnd && !aOther.mIsEnd);
michael@0:   }
michael@0: 
michael@0:   bool operator<=(const nsSMILMilestone& aOther) const
michael@0:   {
michael@0:     return *this == aOther || *this < aOther;
michael@0:   }
michael@0: 
michael@0:   bool operator>=(const nsSMILMilestone& aOther) const
michael@0:   {
michael@0:     return !(*this < aOther);
michael@0:   }
michael@0: 
michael@0:   nsSMILTime   mTime;  // The milestone time. This may be in container time or
michael@0:                        // parent container time depending on where it is used.
michael@0:   bool mIsEnd; // true if this milestone corresponds to an interval
michael@0:                        // end, false otherwise.
michael@0: };
michael@0: 
michael@0: #endif // NS_SMILMILESTONE_H_