Class SchedulerRunner

packages/effect/src/Scheduler.ts:31–87

 * @category models
 */
export class SchedulerRunner {
  running = false
  tasks = new PriorityBuckets()

  constructor(
    readonly scheduleDrain: (depth: number, drain: (depth: number) => void) => void
  ) {}

  private starveInternal = (depth: number) => {
    const tasks = this.tasks.buckets
    this.tasks.buckets = []
    for (const [_, toRun] of tasks) {
      for (let i = 0; i < toRun.length; i++) {
        toRun[i]()
      }
    }
    if (this.tasks.buckets.length === 0) {
      this.running = false
    } else {
      this.starve(depth)
    }
  }

  private starve(depth = 0) {
    this.scheduleDrain(depth, this.starveInternal)
  }

  scheduleTask(task: Task, priority: number) {
    this.tasks.scheduleTask(task, priority)
    if (!this.running) {
      this.running = true
      this.starve()
    }
  }
  /**
   * @since 3.20.0
   * @category constructors
   */
  static cached(
    scheduleDrain: (depth: number, drain: (depth: number) => void) => void
  ) {
    const fallback = new SchedulerRunner(scheduleDrain)
    const runners = new WeakMap<RuntimeFiber<unknown, unknown>, SchedulerRunner>()

    return (fiber?: RuntimeFiber<unknown, unknown>) => {
      if (fiber === undefined) {
        return fallback
      }
      let runner = runners.get(fiber)
      if (runner === undefined) {
        runner = new SchedulerRunner(scheduleDrain)
        runners.set(fiber, runner)
      }
      return runner
    }
  }
}