This patch also reworks the dispatch of events in nsRefreshDriver. Previously
the refresh driver would dispatch the transition events for all subdocuments
then the animation events. This arrangement is complicated and not obviously
necessary. This patch simplifies this arrangement by dispatching transition
events and animation events for each document before proceeding to
subdocuments.
In order to sort between events that have the same timestamp we use the
sort order of the corresponding animations so we need to store a pointer
to the animation along with the event.
This patch lines up the parameters of AnimationEventInfo and
TransitionEventInfo constructors so that they are more logical and consistent.
Specifically, it groups the element and pseudo type together since they
form a logical pair denoting the event target. For AnimationEventInfo this
patch also places the type of event before the common event parameters since
the event type seems to be more significant.
This patch also performs some miscelleaneous housekeeping: removing some
unnecessary namespace prefixes, whitespace fixes, and making
TransitionEventInfo use the same concrete type to store the target element
as AnimationEventInfo (dom::Element instead of nsIContent).
In the new composite order arrangement CSSAnimations and CSSTransition have the
following life-cycle:
1. Animation created by markup
=> composite order determined by markup
(e.g. CSS animations use tree order and animation-name order;
CSS transitions use transition trigger order)
2. Animation cancelled by changing markup
=> composite order is undefined
3. Animation is played again using the API
=> composite order is defined by when the animation is first played.
Another way of saying this is that, at the point when the animation is
played, it is appended to the "global animation list".
4. Animation is subsequently cancelled / played => no change
We need a way to know when we are going from 2 to 3. It would seem like we
could do that by setting mAnimationIndex to some sentinel value while it is
in 2. However, even when in 2, although the spec doesn't define the composite
order animations at this point (from an API point of view you can't access these
objects and they don't contribute to style so it doesn't need to be defined), we
sometimes will need to establish an order.
This can happen, for example, when an animation queues events and then is later
cancelled before the events are dispatched. Because we sort events based on
their associated animation at the time of dispatch (for performance reasons) we
need a deterministic order for these idle animations.
We do that (in a subsequent patch in this series) by setting mAnimationIndex
when we transition from 1 to 2. That is, these idle animations are effectively
ordered by when they became idle (which always happens in a deterministic
fashion).
The Web Animations specification has replaced the term "sequence number" with
references to a global animation list. This patch applies similar naming
to our animation structures.
We currently determine if we need refresh driver ticks when composing style
but sometimes we might not need ticks for composing style but we might need
one more tick in order to queue a final end event. Currently, this doesn't
seem to be a problem because FlushAnimations calls Animation::Tick where we
queue up events. When we remove the call to Animation::Tick from
FlushAnimations in order to make FlushAnimations purely responsible for
posting restyles, however, we will create a situation where we might mark an
animation collection as no longer needing refreshes and not simultaneously
queueing the corresponding event. If another animation collection is deleted in
the meantime we may trigger the code that causes us to disassociate from the
refresh driver and the corresponding event will never be dispatched.
Long-term (bug 1195180) we will check if it we can stop observing the refresh
driver and queue events in the same step. Until then, this patch adds a method
to detect this particular situation and uses it to avoid unregistering from
the refresh driver while we still have end events to queue.
nsTransitionManager::WillRefresh and nsAnimationManager::WillRefresh are now
identical and all methods they call exist on CommonAnimationManager so we
can unify them there.
The implementations of FlushAnimations and FlushTransitions should now be all
but equivalent so this patch combines them into a single implementation on
CommonAnimationManager.
Regarding some of the minor differences between the two methods:
* The combined implementation drops the check for an empty list of collections
found only in FlushTransitions. This seems like a very minor optimization
that could possibly cause us to fail to unregister from the refresh driver
if we forgot to do so when removing the last collection.
* The combined implementation uses the loop implementation from FlushAnimations
since it is more compact.
This patch also removes the extra nested scope since it doesn't seem necessary.
This patch causes transition events to be dispatched as a separate step after
sampling the transitions. Eventually this will allow us to sample transitions
from their timeline (independently of where they came from and in potentially
any order) by separating the concepts of sampling and event dispatch.
This patch moves the logic for queueing events out of the logic for flushing
transitions making it a separate step. It still doesn't delay the dispatch of
those events into a separate step, however. That is done in a subsequent patch.
This patch also makes sure to clear any queued events when the nsPresShell that
owns the transition manager is destroyed. We don't expect CSSTransition::Tick to
be called anywhere except nsTransitionManger::FlushTransitions so there
shouldn't be any orphaned events but for completeness it seems best to add this
now. (Later, when we tick transitions from their timeline we will need this.)
This patch introduces a separate flag to CSSTransition for tracking if a
transition is newly-finished so we can correctly dispatch the transitionend
event. Although, this may seem to be redundant with the "IsFinishedTransition"
we also track, that state will soon be removed in bug 1181392 and hence this
flag will be needed then.
Note that Animation already has flags mIsPreviousStateFinished and
mFinishedAtLastComposeStyle which would appear to be similar however,
- mIsPreviousStateFinished will be removed in bug 1178665 and is updated more
often than we queue events so it is not useful here.
- mFinishedAtLastComposeStyle is used to determine if we can throttle a style
update and is also updated more frequently than we queue events and hence
can't be used here.
Once we guarantee one call to Tick() per frame we may be able to simplify this
by tracking "state on last tick" but for now we need this additional flag on
CSSTransition. CSSAnimation has a similar flag for this
(mPreviousPhaseOrIteration) which we may be able to unify at the same point.
This simply uses the DelayedEventDispatcher in place of the previous array of
TransitionEventInfo objects. Doing the actual delayed dispatch is performed in
a separate patch.
The long-term plan is to drop the mozilla::css namespace altogether. Before we
go to much further with refactoring code in AnimationCommon, we should drop
usage of the mozilla::css namespace. Specifically, this patch moves the
CommonAnimationManager and AnimValuesStyleRule classes to the mozilla namespace.
This patch causes transition events to be dispatched as a separate step after
sampling the transitions. Eventually this will allow us to sample transitions
from their timeline (independently of where they came from and in potentially
any order) by separating the concepts of sampling and event dispatch.
This patch moves the logic for queueing events out of the logic for flushing
transitions making it a separate step. It still doesn't delay the dispatch of
those events into a separate step, however. That is done in a subsequent patch.
This patch also makes sure to clear any queued events when the nsPresShell that
owns the transition manager is destroyed. We don't expect CSSTransition::Tick to
be called anywhere except nsTransitionManger::FlushTransitions so there
shouldn't be any orphaned events but for completeness it seems best to add this
now. (Later, when we tick transitions from their timeline we will need this.)
This patch introduces a separate flag to CSSTransition for tracking if a
transition is newly-finished so we can correctly dispatch the transitionend
event. Although, this may seem to be redundant with the "IsFinishedTransition"
we also track, that state will soon be removed in bug 1181392 and hence this
flag will be needed then.
Note that Animation already has flags mIsPreviousStateFinished and
mFinishedAtLastComposeStyle which would appear to be similar however,
- mIsPreviousStateFinished will be removed in bug 1178665 and is updated more
often than we queue events so it is not useful here.
- mFinishedAtLastComposeStyle is used to determine if we can throttle a style
update and is also updated more frequently than we queue events and hence
can't be used here.
Once we guarantee one call to Tick() per frame we may be able to simplify this
by tracking "state on last tick" but for now we need this additional flag on
CSSTransition. CSSAnimation has a similar flag for this
(mPreviousPhaseOrIteration) which we may be able to unify at the same point.
This simply uses the DelayedEventDispatcher in place of the previous array of
TransitionEventInfo objects. Doing the actual delayed dispatch is performed in
a separate patch.
The long-term plan is to drop the mozilla::css namespace altogether. Before we
go to much further with refactoring code in AnimationCommon, we should drop
usage of the mozilla::css namespace. Specifically, this patch moves the
CommonAnimationManager and AnimValuesStyleRule classes to the mozilla namespace.
The bulk of this commit was generated by running:
run-clang-tidy.py \
-checks='-*,llvm-namespace-comment' \
-header-filter=^/.../mozilla-central/.* \
-fix
The connection between an Animation and an AnimationTimeline is optional. That
is, it is possible to have an Animation without an AnimationTimeline. Until now
we have often just assumed the timeline will be set but eventually we need to
support the possibility of the timeline being null. Indeed, later in this patch
series we will set the timeline out-of-band (i.e. not in the constructor) using
SetTimeline which opens up the possibility that timeline will be null for
a period of time.
This patch paves the way for having an optional timeline by storing the global
used for, e.g. creating promises, on the Animation object itself.
This patch adds a convenience method for getting the transition property for
a CSS transition (so we can use this when ordering CSS transitions).
We already have ElementPropertyTransition::TransitionProperty() so this might
seem to be redundant, however we add this now because:
* In the proposed CSS Transitions <-> Web Animations integration, the
CSSTransition interface has a transitionProperty member so we'll need this
function for that.
* Once we allow script to modify the transition, we'll need to track the
original transition property for sorting purposes which is what this method
should do.
* We'll possibly drop ElementPropertyTransition::TransitionProperty() in the
future.
Similar to the earlier patch in this series that changed the sequence number
handling for animations, this patch re-uses Animation::mSequenceNum to store
the animation generation number when each transition was generated. When the
transition is cancelled it reverts to using the default animation composite
ordering.
