Class StdinBuffer

Platforms/emscripten/web_example/python.worker.mjs:3–38

import createEmscriptenModule from "./python.mjs";

class StdinBuffer {
  constructor() {
    this.sab = new SharedArrayBuffer(128 * Int32Array.BYTES_PER_ELEMENT);
    this.buffer = new Int32Array(this.sab);
    this.readIndex = 1;
    this.numberOfCharacters = 0;
    this.sentNull = true;
  }

  prompt() {
    this.readIndex = 1;
    Atomics.store(this.buffer, 0, -1);
    postMessage({
      type: "stdin",
      buffer: this.sab,
    });
    Atomics.wait(this.buffer, 0, -1);
    this.numberOfCharacters = this.buffer[0];
  }

  stdin = () => {
    while (this.numberOfCharacters + 1 === this.readIndex) {
      if (!this.sentNull) {
        // Must return null once to indicate we're done for now.
        this.sentNull = true;
        return null;
      }
      this.sentNull = false;
      // Prompt will reset this.readIndex to 1
      this.prompt();
    }
    const char = this.buffer[this.readIndex];
    this.readIndex += 1;
    return char;
  };
}

const stdout = (charCode) => {
  if (charCode) {