ch340-webusb/ch340-serial-shim.js

/*!
 * ch340-serial-shim.js — 让 WebUSB 的 CH340 变成 navigator.serial
 * ------------------------------------------------------------------
 * 桌面 Chrome/Edge 本来就有 Web Serial，一行 port.open({baudRate}) 就能用 CH340。
 * 安卓 Chrome 有 WebUSB 但没有 Web Serial，于是所有 "Connect USB" 都会显示不支持。
 * 本垫片在安卓上补出 navigator.serial：requestPort() 打开的是 WebUSB 的 CH340，
 * 返回的对象与 SerialPort 语义一致（open/close/getInfo/readable/writable/setSignals），
 * 于是已有串口业务代码（包括打包好的 SPA）零改动即可在安卓浏览器里跑。
 *
 * 加载顺序（重要）：
 *   <script src="/ch340-webusb.js?v=1"></script>
 *   <script src="/ch340-serial-shim.js?v=1"></script>      <!-- 放在其它 navigator.serial 垫片之前 -->
 *   <script src="/bluetooth-serial-shim.js?v=1"></script>  <!-- 它仍会暴露 window.__btSerial -->
 *   <script src="/业务 bundle.js"></script>
 *
 * 可选配置：加载前设置 window.__CH340_SHIM
 *   { autoInstall:true, baudRate:460800, allDrivers:false, force:false, prefer:'usb' }
 *   window.__CH340_PREFER = 'bluetooth' → 在 chain 模式下让位给原有垫片（例如 BLE）
 * 许可：MIT
 */
(function () {
  'use strict';

  var g = typeof globalThis !== 'undefined' ? globalThis : (typeof window !== 'undefined' ? window : this);
  var api = g.TamaCh340;
  var state = { installed: false, reason: null, previous: null };
  var listeners = { connect: [], disconnect: [] };

  function merge(a, b) {
    var out = {}, k;
    for (k in (a || {})) if (Object.prototype.hasOwnProperty.call(a, k)) out[k] = a[k];
    for (k in (b || {})) if (Object.prototype.hasOwnProperty.call(b, k)) out[k] = b[k];
    return out;
  }

  /** Web Serial 的 filters([{usbVendorId,usbProductId}]) → WebUSB filters */
  function toUsbFilters(serialOptions, fallbackOptions) {
    var f = serialOptions && serialOptions.filters;
    if (Array.isArray(f) && f.length) {
      var mapped = f
        .filter(function (x) { return x && x.usbVendorId !== undefined; })
        .map(function (x) { return { vendorId: x.usbVendorId, productId: x.usbProductId }; });
      if (mapped.length) return mapped;
    }
    if (fallbackOptions && fallbackOptions.filters) return fallbackOptions.filters;
    if (fallbackOptions && fallbackOptions.allDrivers) return api.supportedFilters();
    return api.ch34xFilters();
  }

  function emit(type, port) {
    var ev = { type: type, port: port, target: null };
    var arr = listeners[type] || [];
    for (var i = 0; i < arr.length; i++) { try { arr[i](ev); } catch (e) {} }
    var serial = g.navigator && g.navigator.serial;
    var handler = serial && (type === 'connect' ? serial.onconnect : serial.ondisconnect);
    if (typeof handler === 'function') { try { handler(ev); } catch (e) {} }
  }

  /** 包装端口：补齐 Web Serial 的细节语义 */
  function wrap(port) {
    if (port.__ch340Wrapped) return port;
    port.__ch340Wrapped = true;
    port._signals = { dataTerminalReady: false, requestToSend: false };
    var rawSet = port.setSignals.bind(port);
    port.setSignals = async function (sig) {
      sig = sig || {};
      await rawSet(sig);
      if (sig.dataTerminalReady !== undefined) port._signals.dataTerminalReady = !!sig.dataTerminalReady;
      if (sig.requestToSend !== undefined) port._signals.requestToSend = !!sig.requestToSend;
    };
    port.getSignals = async function () {
      return {
        dataCarrierDetect: false, clearToSend: false, ringIndicator: false,
        dataSetReady: !!port.opened,
        dataTerminalReady: port._signals.dataTerminalReady,
        requestToSend: port._signals.requestToSend
      };
    };
    return port;
  }

  /**
   * 安装垫片
   * @returns {{ok:boolean, reason?:string}}
   */
  function install(options) {
    options = options || {};
    var nav = g.navigator;
    if (!nav) { state.reason = '没有 navigator'; return { ok: false, reason: state.reason }; }
    if (!api) { state.reason = '请先加载 ch340-webusb.js'; return { ok: false, reason: state.reason }; }
    if (!nav.usb) { state.reason = '这个浏览器没有 WebUSB（iOS 不支持）'; return { ok: false, reason: state.reason }; }
    if (nav.serial && nav.serial.__ch340Shim) {
      state.installed = true; state.reason = null; return { ok: true, reason: 'already' };
    }
    if (nav.serial && !options.force) {
      state.reason = 'navigator.serial 已存在（桌面浏览器或其它垫片先装了）；需要接管请传 {force:true}';
      return { ok: false, reason: state.reason };
    }

    var previous = nav.serial || null;
    state.previous = previous;

    async function usbRequestPort(serialOptions) {
      var filters = toUsbFilters(serialOptions, options);
      var device = await nav.usb.requestDevice({ filters: filters });
      return wrap(api.fromDevice(device, merge(options, serialOptions)));
    }

    nav.serial = {
      __ch340Shim: true,
      __previous: previous,
      requestPort: async function (serialOptions) {
        var prefer = g.__CH340_PREFER || options.prefer || 'usb';
        if (prefer === 'bluetooth' && previous && previous.requestPort) {
          return previous.requestPort(serialOptions);
        }
        try {
          return await usbRequestPort(serialOptions);
        } catch (e) {
          // 用户取消 USB 选择框时，可选回退到原有垫片（例如 BLE）
          if (e && e.name === 'NotFoundError' && options.fallbackOnCancel && previous && previous.requestPort) {
            return previous.requestPort(serialOptions);
          }
          throw e;
        }
      },
      getPorts: async function () {
        var devices = await api.getAuthorizedDevices(options);
        return devices.map(function (d) { return wrap(api.fromDevice(d, options)); });
      },
      addEventListener: function (type, fn) { if (listeners[type]) listeners[type].push(fn); },
      removeEventListener: function (type, fn) {
        if (!listeners[type]) return;
        listeners[type] = listeners[type].filter(function (f) { return f !== fn; });
      },
      onconnect: null,
      ondisconnect: null
    };

    // 拔插事件透传（业务代码常靠它做重连）
    try {
      nav.usb.addEventListener('connect', function (ev) {
        var d = ev && ev.device;
        if (!d) return;
        try { emit('connect', wrap(api.fromDevice(d, options))); } catch (e) {}
      });
      nav.usb.addEventListener('disconnect', function (ev) {
        var d = ev && ev.device;
        if (!d) { emit('disconnect', null); return; }
        try { emit('disconnect', wrap(api.fromDevice(d, options))); } catch (e) { emit('disconnect', null); }
      });
    } catch (e) { /* 个别实现没有 addEventListener，忽略 */ }

    state.installed = true;
    state.reason = null;
    if (api.debug && typeof console !== 'undefined') console.log('[ch340] navigator.serial 垫片已安装');
    return { ok: true };
  }

  g.TamaSerialShim = {
    install: install,
    get installed() { return state.installed; },
    get reason() { return state.reason; },
    get previous() { return state.previous; },
    version: api ? api.version : null
  };

  // ── 自动安装：有 WebUSB 且没有 navigator.serial 时装上（安卓默认走这条；桌面不动） ──
  var cfg = merge({ autoInstall: true, baudRate: 460800 }, g.__CH340_SHIM);
  if (cfg.autoInstall && g.navigator && g.navigator.usb && !g.navigator.serial && api) {
    var res = install(cfg);
    if (api.debug && typeof console !== 'undefined') console.log('[ch340] 自动安装: ' + JSON.stringify(res));
  }
})();