0.10.0: Archify Sync, optional live collaboration on a model

Several people edit one model at once through a server you run yourself
(archify-vscode-ext-sync); the files stay ordinary files on each disk.
Sign-in through the browser, offline-first with later merge, teammates'
cursors in the Source view and text editors, and a Shared section on the
model page with people, versions, Compare and Restore.

Without a server nothing changes: the sync code is a separate bundle that
loads only when a model is shared, after a sign-in, or when a sync command
or invite link is used.

src/sync/liveBridge.ts

@@ -0,0 +1,110 @@
+import * as vscode from 'vscode';
+
+// What the model page shows of a shared model. Lives in the main bundle; the
+// sync bundle plugs in as the provider once it loads. Without it, the model
+// page has no Live section and nothing else changes.
+
+export interface LivePerson {
+  name: string;
+  /** Model-relative path of the file the person has open. */
+  file?: string;
+  me?: boolean;
+}
+
+export interface LiveVersion {
+  id: number;
+  label: string;
+  kind: 'snapshot' | 'publish' | 'restore';
+  name?: string;
+  /** ISO time. */
+  at: string;
+  restoredFrom?: string;
+}
+
+export interface LivePanel {
+  name: string;
+  host: string;
+  state: 'connecting' | 'online' | 'offline' | 'signed-out' | 'forbidden' | 'outdated';
+  people: LivePerson[];
+  versions?: LiveVersion[];
+  versionsProblem?: string;
+}
+
+/** Someone else's cursor in a file, as offsets into its "\n" text. */
+export interface LiveCursor {
+  name: string;
+  color: string;
+  anchor: number;
+  head: number;
+}
+
+/** A selection as offsets into a file's "\n" text. */
+export interface LiveSelection {
+  anchor: number;
+  head: number;
+}
+
+export type LiveAction =
+  | { kind: 'publish' }
+  | { kind: 'invite' }
+  | { kind: 'signIn' }
+  | { kind: 'versions' }
+  | { kind: 'compare'; version: number }
+  | { kind: 'restore'; version: number };
+
+export interface LiveProvider {
+  panel(root: vscode.Uri): Promise<LivePanel | undefined>;
+  act(root: vscode.Uri, action: LiveAction): Promise<void>;
+  /** Others' cursors in a shared file; empty when the file is not shared. */
+  cursors(file: vscode.Uri): LiveCursor[];
+  /** This person's cursor in a page's Source view; undefined when it closes. */
+  setCursor(file: vscode.Uri, selection: LiveSelection | undefined): void;
+}
+
+class LiveBridge implements vscode.Disposable {
+  private provider: LiveProvider | undefined;
+  private readonly emitter = new vscode.EventEmitter<vscode.Uri | undefined>();
+  /** A model root whose Live section changed; undefined for all of them. */
+  readonly onDidChange = this.emitter.event;
+  private readonly cursorEmitter = new vscode.EventEmitter<void>();
+  /** Someone's cursor moved somewhere; ask `cursors` for the file you show. */
+  readonly onDidChangeCursors = this.cursorEmitter.event;
+
+  setProvider(provider: LiveProvider | undefined): void {
+    this.provider = provider;
+    this.emitter.fire(undefined);
+    this.cursorEmitter.fire();
+  }
+
+  changed(root?: vscode.Uri): void {
+    this.emitter.fire(root);
+  }
+
+  async panel(root: vscode.Uri): Promise<LivePanel | undefined> {
+    return this.provider?.panel(root);
+  }
+
+  async act(root: vscode.Uri, action: LiveAction): Promise<void> {
+    await this.provider?.act(root, action);
+  }
+
+  cursorsChanged(): void {
+    this.cursorEmitter.fire();
+  }
+
+  cursors(file: vscode.Uri): LiveCursor[] {
+    return this.provider?.cursors(file) ?? [];
+  }
+
+  setCursor(file: vscode.Uri, selection: LiveSelection | undefined): void {
+    this.provider?.setCursor(file, selection);
+  }
+
+  dispose(): void {
+    this.emitter.dispose();
+    this.cursorEmitter.dispose();
+  }
+}
+
+export const liveBridge = new LiveBridge();
+export type { LiveBridge };