initial commit: scaffolding

1 files changed, 150 insertions, 0 deletions

diff --git a/node_modules/rxjs/src/internal/scheduler/AsyncAction.ts b/node_modules/rxjs/src/internal/scheduler/AsyncAction.ts
new file mode 100644
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--- /dev/null
+++ b/node_modules/rxjs/src/internal/scheduler/AsyncAction.ts
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+import { Action } from './Action';
+import { SchedulerAction } from '../types';
+import { Subscription } from '../Subscription';
+import { AsyncScheduler } from './AsyncScheduler';
+import { intervalProvider } from './intervalProvider';
+import { arrRemove } from '../util/arrRemove';
+import { TimerHandle } from './timerHandle';
+
+export class AsyncAction<T> extends Action<T> {
+  public id: TimerHandle | undefined;
+  public state?: T;
+  // @ts-ignore: Property has no initializer and is not definitely assigned
+  public delay: number;
+  protected pending: boolean = false;
+
+  constructor(protected scheduler: AsyncScheduler, protected work: (this: SchedulerAction<T>, state?: T) => void) {
+    super(scheduler, work);
+  }
+
+  public schedule(state?: T, delay: number = 0): Subscription {
+    if (this.closed) {
+      return this;
+    }
+
+    // Always replace the current state with the new state.
+    this.state = state;
+
+    const id = this.id;
+    const scheduler = this.scheduler;
+
+    //
+    // Important implementation note:
+    //
+    // Actions only execute once by default, unless rescheduled from within the
+    // scheduled callback. This allows us to implement single and repeat
+    // actions via the same code path, without adding API surface area, as well
+    // as mimic traditional recursion but across asynchronous boundaries.
+    //
+    // However, JS runtimes and timers distinguish between intervals achieved by
+    // serial `setTimeout` calls vs. a single `setInterval` call. An interval of
+    // serial `setTimeout` calls can be individually delayed, which delays
+    // scheduling the next `setTimeout`, and so on. `setInterval` attempts to
+    // guarantee the interval callback will be invoked more precisely to the
+    // interval period, regardless of load.
+    //
+    // Therefore, we use `setInterval` to schedule single and repeat actions.
+    // If the action reschedules itself with the same delay, the interval is not
+    // canceled. If the action doesn't reschedule, or reschedules with a
+    // different delay, the interval will be canceled after scheduled callback
+    // execution.
+    //
+    if (id != null) {
+      this.id = this.recycleAsyncId(scheduler, id, delay);
+    }
+
+    // Set the pending flag indicating that this action has been scheduled, or
+    // has recursively rescheduled itself.
+    this.pending = true;
+
+    this.delay = delay;
+    // If this action has already an async Id, don't request a new one.
+    this.id = this.id ?? this.requestAsyncId(scheduler, this.id, delay);
+
+    return this;
+  }
+
+  protected requestAsyncId(scheduler: AsyncScheduler, _id?: TimerHandle, delay: number = 0): TimerHandle {
+    return intervalProvider.setInterval(scheduler.flush.bind(scheduler, this), delay);
+  }
+
+  protected recycleAsyncId(_scheduler: AsyncScheduler, id?: TimerHandle, delay: number | null = 0): TimerHandle | undefined {
+    // If this action is rescheduled with the same delay time, don't clear the interval id.
+    if (delay != null && this.delay === delay && this.pending === false) {
+      return id;
+    }
+    // Otherwise, if the action's delay time is different from the current delay,
+    // or the action has been rescheduled before it's executed, clear the interval id
+    if (id != null) {
+      intervalProvider.clearInterval(id);
+    }
+
+    return undefined;
+  }
+
+  /**
+   * Immediately executes this action and the `work` it contains.
+   */
+  public execute(state: T, delay: number): any {
+    if (this.closed) {
+      return new Error('executing a cancelled action');
+    }
+
+    this.pending = false;
+    const error = this._execute(state, delay);
+    if (error) {
+      return error;
+    } else if (this.pending === false && this.id != null) {
+      // Dequeue if the action didn't reschedule itself. Don't call
+      // unsubscribe(), because the action could reschedule later.
+      // For example:
+      // ```
+      // scheduler.schedule(function doWork(counter) {
+      //   /* ... I'm a busy worker bee ... */
+      //   var originalAction = this;
+      //   /* wait 100ms before rescheduling the action */
+      //   setTimeout(function () {
+      //     originalAction.schedule(counter + 1);
+      //   }, 100);
+      // }, 1000);
+      // ```
+      this.id = this.recycleAsyncId(this.scheduler, this.id, null);
+    }
+  }
+
+  protected _execute(state: T, _delay: number): any {
+    let errored: boolean = false;
+    let errorValue: any;
+    try {
+      this.work(state);
+    } catch (e) {
+      errored = true;
+      // HACK: Since code elsewhere is relying on the "truthiness" of the
+      // return here, we can't have it return "" or 0 or false.
+      // TODO: Clean this up when we refactor schedulers mid-version-8 or so.
+      errorValue = e ? e : new Error('Scheduled action threw falsy error');
+    }
+    if (errored) {
+      this.unsubscribe();
+      return errorValue;
+    }
+  }
+
+  unsubscribe() {
+    if (!this.closed) {
+      const { id, scheduler } = this;
+      const { actions } = scheduler;
+
+      this.work = this.state = this.scheduler = null!;
+      this.pending = false;
+
+      arrRemove(actions, this);
+      if (id != null) {
+        this.id = this.recycleAsyncId(scheduler, id, null);
+      }
+
+      this.delay = null!;
+      super.unsubscribe();
+    }
+  }
+}