Class ReplayWindowImpl

repos/effect/packages/effect/src/PubSub.ts:2742–2790

  constructor(buffer: ReplayBuffer<A>) {
    this.buffer = buffer
    this.remaining = buffer.size
    this.slideIndex = buffer.index
    this.values = new Array(this.remaining)
    let node = buffer.head
    for (let i = 0; i < this.remaining; i++) {
      this.values[i] = node.value as A
      this.newestIndex = node.index
      node = node.next!
    }
  }
  close(): void {
    this.values.length = 0
    this.remaining = 0
  }
  sync(): void {
    const slides = this.buffer.index - this.slideIndex
    if (slides === 0 || this.remaining === 0) {
      return
    }
    const count = Math.min(slides, this.buffer.capacity)
    const start = this.buffer.index - count
    for (let i = 0; i < count; i++) {
      const entry = this.buffer.slideValues[(start + i) % this.buffer.capacity]
      if (entry.index > this.newestIndex) {
        this.index = (this.index + 1) % this.values.length
        this.values[(this.index + this.remaining - 1) % this.values.length] = entry.value
        this.newestIndex = entry.index
      }
    }
    this.slideIndex = this.buffer.index
  }
  take(): A | undefined {
    if (this.remaining === 0) {
      return undefined
    }
    this.sync()
    const value = this.values[this.index]
    this.values[this.index] = AbsentValue as unknown as A
    this.index = (this.index + 1) % this.values.length
    this.remaining--
    if (this.remaining === 0) {
      this.close()
    }
    return value as A
  }
  takeN(n: number): Array<A> {
    const len = Math.min(n, this.remaining)
    const items = new Array(len)
    for (let i = 0; i < len; i++) {
      items[i] = this.take()!
    }