import { AsyncAction } from './AsyncAction';
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import { AnimationFrameScheduler } from './AnimationFrameScheduler';
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import { SchedulerAction } from '../types';
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import { animationFrameProvider } from './animationFrameProvider';
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import { TimerHandle } from './timerHandle';
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export class AnimationFrameAction<T> extends AsyncAction<T> {
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constructor(protected scheduler: AnimationFrameScheduler, protected work: (this: SchedulerAction<T>, state?: T) => void) {
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super(scheduler, work);
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}
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protected requestAsyncId(scheduler: AnimationFrameScheduler, id?: TimerHandle, delay: number = 0): TimerHandle {
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// If delay is greater than 0, request as an async action.
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if (delay !== null && delay > 0) {
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return super.requestAsyncId(scheduler, id, delay);
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}
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// Push the action to the end of the scheduler queue.
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scheduler.actions.push(this);
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// If an animation frame has already been requested, don't request another
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// one. If an animation frame hasn't been requested yet, request one. Return
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// the current animation frame request id.
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return scheduler._scheduled || (scheduler._scheduled = animationFrameProvider.requestAnimationFrame(() => scheduler.flush(undefined)));
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}
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protected recycleAsyncId(scheduler: AnimationFrameScheduler, id?: TimerHandle, delay: number = 0): TimerHandle | undefined {
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// If delay exists and is greater than 0, or if the delay is null (the
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// action wasn't rescheduled) but was originally scheduled as an async
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// action, then recycle as an async action.
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if (delay != null ? delay > 0 : this.delay > 0) {
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return super.recycleAsyncId(scheduler, id, delay);
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}
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// If the scheduler queue has no remaining actions with the same async id,
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// cancel the requested animation frame and set the scheduled flag to
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// undefined so the next AnimationFrameAction will request its own.
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const { actions } = scheduler;
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if (id != null && actions[actions.length - 1]?.id !== id) {
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animationFrameProvider.cancelAnimationFrame(id as number);
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scheduler._scheduled = undefined;
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}
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// Return undefined so the action knows to request a new async id if it's rescheduled.
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return undefined;
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}
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}
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