/// <summary>
/// Deactivates and disables this root clock.
/// </summary>
internal void RootDisable()
{
Debug.Assert(IsTimeManager, "Invalid call to RootDeactivate for a non-root Clock");
// Reset the state of the timing tree
WeakRefEnumerator<Clock> enumerator = new WeakRefEnumerator<Clock>(_rootChildren);
while (enumerator.MoveNext())
{
PrefixSubtreeEnumerator subtree = new PrefixSubtreeEnumerator(enumerator.Current, true);
while (subtree.MoveNext())
{
if (subtree.Current.InternalCurrentClockState != ClockState.Stopped)
{
subtree.Current.ResetCachedStateToStopped();
subtree.Current.RaiseCurrentStateInvalidated();
subtree.Current.RaiseCurrentTimeInvalidated();
subtree.Current.RaiseCurrentGlobalSpeedInvalidated();
}
else
{
subtree.SkipSubtree();
}
}
}
}
/// <summary>
/// Removes dead weak references from the child list of the root clock.
/// </summary>
internal void RootCleanChildren()
{
Debug.Assert(IsTimeManager, "Invalid call to RootCleanChildren for a non-root Clock");
WeakRefEnumerator<Clock> enumerator = new WeakRefEnumerator<Clock>(_rootChildren);
// Simply enumerating the children with the weak reference
// enumerator is sufficient to clean up the list. Therefore, the
// body of the loop can remain empty
while (enumerator.MoveNext())
{
}
// When the loop terminates naturally the enumerator will clean
// up the list of any dead references. Therefore, by the time we
// get here we are done.
}
// Called on the root
internal void ComputeTreeState()
{
Debug.Assert(IsTimeManager);
// Revive all children
WeakRefEnumerator<Clock> enumerator = new WeakRefEnumerator<Clock>(_rootChildren);
while (enumerator.MoveNext())
{
PrefixSubtreeEnumerator prefixEnumerator = new PrefixSubtreeEnumerator(enumerator.Current, true);
while (prefixEnumerator.MoveNext())
{
Clock current = prefixEnumerator.Current;
// Only traverse the "ripe" subset of the Timing tree
if (CurrentGlobalTime >= current.InternalNextTickNeededTime)
{
current.ApplyDesiredFrameRateToGlobalTime();
current.ComputeLocalState(); // Compute the state of the node
current.ClipNextTickByParent(); // Perform NextTick clipping, stage 1
// Make a note to visit for stage 2, only for ClockGroups and Roots
current.NeedsPostfixTraversal = (current is ClockGroup) || (current.IsRoot);
}
else
{
prefixEnumerator.SkipSubtree();
}
}
}
// To perform a postfix walk culled by NeedsPostfixTraversal flag, we use a local recursive method
// Note that since we called for this operation, it is probably already needed by the root clock
ComputeTreeStateRoot();
}
internal void ComputeTreeStateRoot()
{
Debug.Assert(IsTimeManager);
TimeSpan? previousTickNeededTime = InternalNextTickNeededTime;
InternalNextTickNeededTime = null; // Reset the root's next tick needed time
WeakRefEnumerator<Clock> enumerator = new WeakRefEnumerator<Clock>(_rootChildren);
while (enumerator.MoveNext())
{
Clock current = enumerator.Current;
if (current.NeedsPostfixTraversal)
{
if (current is ClockGroup)
{
((ClockGroup)current).ComputeTreeStatePostfix();
}
current.ApplyDesiredFrameRateToNextTick(); // Apply the effects of DFR on each root as needed
current.NeedsPostfixTraversal = false; // Reset the flag
}
if(!InternalNextTickNeededTime.HasValue ||
(enumerator.Current.InternalNextTickNeededTime.HasValue &&
enumerator.Current.InternalNextTickNeededTime < InternalNextTickNeededTime))
{
InternalNextTickNeededTime = enumerator.Current.InternalNextTickNeededTime;
}
}
if (InternalNextTickNeededTime.HasValue &&
(!previousTickNeededTime.HasValue || previousTickNeededTime > InternalNextTickNeededTime))
{
_timeManager.NotifyNewEarliestFutureActivity();
}
}
// This is only to be called on the TimeManager clock. Go through our
// top level clocks and find the clock with the highest desired framerate.
// DFR has to be > 0, so starting the accumulator at 0 is fine.
internal int GetMaxDesiredFrameRate()
{
Debug.Assert(IsTimeManager);
int desiredFrameRate = 0;
// Ask all top-level clock their desired framerate
WeakRefEnumerator<Clock> enumerator = new WeakRefEnumerator<Clock>(_rootChildren);
while (enumerator.MoveNext())
{
Clock currentClock = enumerator.Current;
if (currentClock != null && currentClock.CurrentState == ClockState.Active)
{
int? currentDesiredFrameRate = currentClock.DesiredFrameRate;
if (currentDesiredFrameRate.HasValue)
{
desiredFrameRate = Math.Max(desiredFrameRate, currentDesiredFrameRate.Value);
}
}
}
return desiredFrameRate;
}
