feat: 实现SerialProvider

- SerialProvider用于为串口连接提供context

src/lib/serial/index.ts

@@ -0,0 +1,2 @@
+export * from './serial.service';
+export * from './serial.types';

src/lib/serial/serial.providers.svelte

@@ -0,0 +1,103 @@
+<script lang="ts">
+  import { onDestroy, type Snippet } from 'svelte';
+  import { get } from 'svelte/store';
+  import { serialState, setSerialContext } from './serial.store';
+  import * as service from './serial.service';
+
+  interface Props {
+    children?: Snippet;
+  }
+
+  let { children }: Props = $props();
+
+  async function requestPort() {
+    serialState.update((state) => ({
+      ...state,
+      status: 'requesting',
+      error: undefined,
+    }));
+
+    try {
+      const port = await service.requestPort();
+      if (!port) return null;
+
+      const info = port.getInfo?.();
+      const name = info
+        ? `USB ${info.usbVendorId ?? ''}:${info.usbProductId ?? ''}`
+        : 'Serial Device';
+      serialState.update((s) => ({
+        ...s,
+        port,
+        portName: name,
+        status: 'idle',
+      }));
+
+      return port;
+    } catch (err) {
+      serialState.update((s) => ({
+        ...s,
+        status: 'error',
+        error: String(err),
+      }));
+      return null;
+    }
+  }
+
+  async function openPort(options: SerialOptions) {
+    let port = get(serialState).port;
+    if (!port) return;
+
+    serialState.update((s) => ({
+      ...s,
+      status: 'connecting',
+      error: undefined,
+    }));
+
+    try {
+      await service.openPort(port, options);
+      serialState.update((s) => ({ ...s, status: 'connected' }));
+    } catch (err) {
+      serialState.update((s) => ({
+        ...s,
+        status: 'error',
+        error: String(err),
+      }));
+    }
+  }
+
+  async function closePort() {
+    let port = get(serialState).port;
+
+    if (!port) return;
+
+    serialState.update((s) => ({ ...s, status: 'disconnecting' }));
+    await service.closePort(port);
+
+    serialState.update((s) => ({
+      ...s,
+      status: 'idle',
+    }));
+  }
+
+  async function reopenPort(options: SerialOptions) {
+    await closePort();
+    await openPort(options);
+  }
+
+  setSerialContext({
+    state: {
+      subscribe: serialState.subscribe,
+    },
+    requestPort,
+    openPort,
+    reopenPort,
+    closePort,
+  });
+
+  onDestroy(() => {
+    let port = get(serialState).port;
+    if (port) service.closePort(port);
+  });
+</script>
+
+{@render children?.()}

src/lib/serial/serial.service.ts

@@ -0,0 +1,108 @@
+// src/lib/serial/serial.service.ts
+// Web Serial API implementation
+// Requires: @types/w3c-web-serial
+
+/**
+ * 内部IO资源
+ */
+let reader: ReadableStreamDefaultReader<Uint8Array> | null = null;
+let writer: WritableStreamDefaultWriter<Uint8Array> | null = null;
+
+let isOpen = false;
+
+/**
+ * 判断当前环境是否支持Web Serial API
+ */
+export function isWebSerialSupported(): boolean {
+  return typeof navigator !== 'undefined' && 'serial' in navigator;
+}
+
+/**
+ * 请求用户选择串口设备
+ */
+export async function requestPort(
+  filters?: SerialPortRequestOptions['filters']
+): Promise<SerialPort | null> {
+  if (!isWebSerialSupported()) {
+    throw new Error('Web Serial API is not supported in this environment.');
+  }
+
+  const port = await navigator.serial.requestPort(
+    filters ? { filters } : undefined
+  );
+
+  return port ?? null;
+}
+
+/**
+ * 打开串口
+ */
+export async function openPort(
+  port: SerialPort,
+  options: SerialOptions
+): Promise<void> {
+  if (isOpen) {
+    // 串口已经打开，直接返回
+    return;
+  }
+
+  await port.open(options);
+  isOpen = true;
+
+  // 初始化reader和writer
+  reader = port.readable?.getReader() ?? null;
+  writer = port.writable?.getWriter() ?? null;
+}
+
+/**
+ * 关闭串口
+ */
+export async function closePort(port: SerialPort) {
+  if (!isOpen) {
+    // 串口未打开，直接返回
+    return;
+  }
+
+  await reader?.cancel();
+  reader?.releaseLock();
+  await writer?.close();
+  writer?.releaseLock();
+
+  reader = null;
+  writer = null;
+  isOpen = false;
+
+  await port.close();
+}
+
+/**
+ * 向串口写入数据
+ */
+export async function write(data: Uint8Array): Promise<void> {
+  if (!writer) {
+    throw new Error('Serial port is not writable.');
+  }
+  await writer.write(data);
+}
+
+/**
+ * 开始读取串口数据循环
+ */
+export async function startReadLoop(
+  onData: (chunk: Uint8Array) => void,
+  onError?: (err: unknown) => void
+): Promise<void> {
+  if (!reader) {
+    throw new Error('Serial port is not readable.');
+  }
+
+  try {
+    while (true) {
+      const { value, done } = await reader.read();
+      if (done) break;
+      if (value) onData(value);
+    }
+  } catch (err) {
+    onError?.(err);
+  }
+}

src/lib/serial/serial.store.ts

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+import { writable } from 'svelte/store';
+import { createContext } from 'svelte';
+import type { SerialState, SerialContext } from './serial.types';
+
+export const serialState = writable<SerialState>({
+  port: null,
+  portName: null,
+  status: 'idle',
+  error: undefined,
+});
+
+export const [getSerialContext, setSerialContext] =
+  createContext<SerialContext>();

src/lib/serial/serial.types.ts

@@ -0,0 +1,24 @@
+import type { Readable } from 'svelte/store';
+
+export type SerialStatus =
+  | 'idle'
+  | 'requesting'
+  | 'connecting'
+  | 'connected'
+  | 'disconnecting'
+  | 'error';
+
+export type SerialState = {
+  port: SerialPort | null;
+  portName: string | null;
+  status: SerialStatus;
+  error?: string;
+};
+
+export type SerialContext = {
+  state: Readable<SerialState>;
+  requestPort: () => Promise<SerialPort | null>;
+  openPort: (options: SerialOptions) => Promise<void>;
+  reopenPort: (options: SerialOptions) => Promise<void>;
+  closePort: () => Promise<void>;
+};

src/routes/+layout.svelte

@@ -1,9 +1,13 @@
 <script lang="ts">
   import './layout.css';
   import favicon from '$lib/assets/favicon.svg';
+  import SerialProvider from '$lib/serial/serial.providers.svelte';
 
   let { children } = $props();
 </script>
 
 <svelte:head><link rel="icon" href={favicon} /></svelte:head>
-{@render children()}
+
+<SerialProvider>
+  {@render children()}
+</SerialProvider>