remove fs-ext due to its deps, use kill(pid, 0) for instance lock

.gitignore

@@ -31,6 +31,7 @@ dependency-graph.png
 dump.rdb
 
 RUNNING_PID
+instance.lock
 .DS_Store
 
 # Eclipse auto-generated files

ui/.build/package.json

@@ -14,14 +14,12 @@
     "sass-embedded-win32-x64": "1.83.3"
   },
   "dependencies": {
-    "@types/fs-ext": "^2.0.3",
     "@types/micromatch": "^4.0.9",
     "@types/node": "22.12.0",
     "@types/tinycolor2": "1.4.6",
     "esbuild": "0.24.2",
     "fast-glob": "3.3.3",
     "fast-xml-parser": "4.5.1",
-    "fs-ext": "^2.1.1",
     "micromatch": "4.0.8",
     "tinycolor2": "1.6.0",
     "typescript": "5.7.3"

ui/.build/src/env.ts

@@ -16,6 +16,7 @@ export const env = new (class {
   readonly themeDir = p.join(this.uiDir, 'common', 'css', 'theme');
   readonly themeGenDir = p.join(this.themeDir, 'gen');
   readonly buildDir = p.join(this.uiDir, '.build');
+  readonly lockFile = p.join(this.buildDir, 'instance.lock');
   readonly cssTempDir = p.join(this.buildDir, 'build', 'css');
   readonly buildSrcDir = p.join(this.uiDir, '.build', 'src');
   readonly buildTempDir = p.join(this.buildDir, 'build');

ui/.build/src/main.ts

@@ -1,12 +1,12 @@
 import ps from 'node:process';
 import fs from 'node:fs';
-import { flockSync, constants } from 'fs-ext';
 import { deepClean } from './clean.ts';
 import { build } from './build.ts';
 import { startConsole } from './console.ts';
 import { env, errorMark } from './env.ts';
 
 // main entry point
+['SIGINT', 'SIGTERM', 'SIGHUP'].forEach(sig => ps.on(sig, () => ps.exit(2)));
 
 const args: Record<string, string> = {
   '--tsc': '',
@@ -112,17 +112,33 @@ if (argv.includes('--help') || oneDashArgs.includes('h')) {
   ps.exit(0);
 }
 
-try {
-  const fd = fs.openSync(env.buildDir, 'r');
-  ps.on('exit', () => fs.closeSync(fd));
-  flockSync(fd, constants.LOCK_EX | constants.LOCK_NB);
-} catch {
-  env.exit(`${errorMark} - Another instance is already running`);
-}
+instanceLock();
 
 if (env.clean) {
   await deepClean();
   if (argv.includes('--clean-exit')) ps.exit(0);
 }
+
 startConsole();
 build(argv.filter(x => !x.startsWith('-')));
+
+function instanceLock(checkStale = true) {
+  try {
+    const fd = fs.openSync(env.lockFile, 'wx');
+    fs.writeFileSync(fd, String(ps.pid), { flag: 'w' });
+    fs.closeSync(fd);
+    console.log('ooya');
+    ps.on('exit', () => fs.unlinkSync(env.lockFile));
+  } catch {
+    const pid = parseInt(fs.readFileSync(env.lockFile, 'utf8'), 10);
+    if (!isNaN(pid) && pid > 0 && ps.platform !== 'win32') {
+      try {
+        ps.kill(pid, 0);
+        env.exit(`${errorMark} - Another instance is already running`);
+      } catch {
+        fs.unlinkSync(env.lockFile); // it's a craplet
+        if (checkStale) return instanceLock(false);
+      }
+    }
+  }
+}

ui/.build/src/sync.ts

@@ -34,6 +34,7 @@ export async function sync(): Promise<any> {
 }
 
 async function syncOne(absSrc: string, absDest: string): Promise<boolean> {
+  // TODO are these stats unnecessary now?
   const [src, dest] = (
     await Promise.allSettled([
       fs.promises.stat(absSrc),