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- import { AsyncAction } from './AsyncAction';
- import { Subscription } from '../Subscription';
- import { AsyncScheduler } from './AsyncScheduler';
- import { SchedulerAction } from '../types';
- import { TimerHandle } from './timerHandle';
- export class VirtualTimeScheduler extends AsyncScheduler {
- /** @deprecated Not used in VirtualTimeScheduler directly. Will be removed in v8. */
- static frameTimeFactor = 10;
- /**
- * The current frame for the state of the virtual scheduler instance. The difference
- * between two "frames" is synonymous with the passage of "virtual time units". So if
- * you record `scheduler.frame` to be `1`, then later, observe `scheduler.frame` to be at `11`,
- * that means `10` virtual time units have passed.
- */
- public frame: number = 0;
- /**
- * Used internally to examine the current virtual action index being processed.
- * @deprecated Internal implementation detail, do not use directly. Will be made internal in v8.
- */
- public index: number = -1;
- /**
- * This creates an instance of a `VirtualTimeScheduler`. Experts only. The signature of
- * this constructor is likely to change in the long run.
- *
- * @param schedulerActionCtor The type of Action to initialize when initializing actions during scheduling.
- * @param maxFrames The maximum number of frames to process before stopping. Used to prevent endless flush cycles.
- */
- constructor(schedulerActionCtor: typeof AsyncAction = VirtualAction as any, public maxFrames: number = Infinity) {
- super(schedulerActionCtor, () => this.frame);
- }
- /**
- * Prompt the Scheduler to execute all of its queued actions, therefore
- * clearing its queue.
- */
- public flush(): void {
- const { actions, maxFrames } = this;
- let error: any;
- let action: AsyncAction<any> | undefined;
- while ((action = actions[0]) && action.delay <= maxFrames) {
- actions.shift();
- this.frame = action.delay;
- if ((error = action.execute(action.state, action.delay))) {
- break;
- }
- }
- if (error) {
- while ((action = actions.shift())) {
- action.unsubscribe();
- }
- throw error;
- }
- }
- }
- export class VirtualAction<T> extends AsyncAction<T> {
- protected active: boolean = true;
- constructor(
- protected scheduler: VirtualTimeScheduler,
- protected work: (this: SchedulerAction<T>, state?: T) => void,
- protected index: number = (scheduler.index += 1)
- ) {
- super(scheduler, work);
- this.index = scheduler.index = index;
- }
- public schedule(state?: T, delay: number = 0): Subscription {
- if (Number.isFinite(delay)) {
- if (!this.id) {
- return super.schedule(state, delay);
- }
- this.active = false;
- // If an action is rescheduled, we save allocations by mutating its state,
- // pushing it to the end of the scheduler queue, and recycling the action.
- // But since the VirtualTimeScheduler is used for testing, VirtualActions
- // must be immutable so they can be inspected later.
- const action = new VirtualAction(this.scheduler, this.work);
- this.add(action);
- return action.schedule(state, delay);
- } else {
- // If someone schedules something with Infinity, it'll never happen. So we
- // don't even schedule it.
- return Subscription.EMPTY;
- }
- }
- protected requestAsyncId(scheduler: VirtualTimeScheduler, id?: any, delay: number = 0): TimerHandle {
- this.delay = scheduler.frame + delay;
- const { actions } = scheduler;
- actions.push(this);
- (actions as Array<VirtualAction<T>>).sort(VirtualAction.sortActions);
- return 1;
- }
- protected recycleAsyncId(scheduler: VirtualTimeScheduler, id?: any, delay: number = 0): TimerHandle | undefined {
- return undefined;
- }
- protected _execute(state: T, delay: number): any {
- if (this.active === true) {
- return super._execute(state, delay);
- }
- }
- private static sortActions<T>(a: VirtualAction<T>, b: VirtualAction<T>) {
- if (a.delay === b.delay) {
- if (a.index === b.index) {
- return 0;
- } else if (a.index > b.index) {
- return 1;
- } else {
- return -1;
- }
- } else if (a.delay > b.delay) {
- return 1;
- } else {
- return -1;
- }
- }
- }
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