Proper rust init in MLComputer isolate

mobile/apps/photos/lib/services/machine_learning/ml_computer.dart

@@ -29,8 +29,6 @@ class MLComputer extends SuperIsolate {
   @override
   bool get shouldAutomaticDispose => false;
 
-  bool _isRustInit = false;
-
   // Singleton pattern
   MLComputer._privateConstructor();
   static final MLComputer instance = MLComputer._privateConstructor();
@@ -44,9 +42,7 @@ class MLComputer extends SuperIsolate {
       final result = await runInIsolate(IsolateOperation.bulkVectorSearch, {
         "clipFloat32": clipFloat32,
         "exact": exact,
-        "initRust": !_isRustInit,
       });
-      _isRustInit = true;
       return result;
     } catch (e, s) {
       _logger.severe("Could not run bulk vector search in MLComputer", e, s);
@@ -161,9 +157,4 @@ class MLComputer extends SuperIsolate {
       rethrow;
     }
   }
-
-  @override
-  Future<void> onDispose() async {
-    _isRustInit = false;
-  }
 }

mobile/apps/photos/lib/utils/isolate/isolate_operations.dart

@@ -63,8 +63,7 @@ Future<dynamic> isolateFunction(
 ) async {
   switch (function) {
     case IsolateOperation.bulkVectorSearch:
-      final initRust = args["initRust"] as bool? ?? false;
-      if (initRust) await RustLib.init();
+      await _ensureRustLoaded();
       final clipFloat32 = args["clipFloat32"] as List<Float32List>;
       final exact = args["exact"] as bool;
 
@@ -199,9 +198,26 @@ Future<dynamic> isolateFunction(
 
     /// Caching
     case IsolateOperation.clearAllIsolateCache:
+      _ensureRustDisposed();
       _isolateCache.clear();
       return true;
 
     /// Cases for Caching stop here
   }
 }
+
+Future<void> _ensureRustLoaded() async {
+  final bool loaded = _isolateCache["rustLibLoaded"] as bool? ?? false;
+  if (!loaded) {
+    await RustLib.init();
+    _isolateCache["rustLibLoaded"] = true;
+  }
+}
+
+void _ensureRustDisposed() {
+  final bool loaded = _isolateCache["rustLibLoaded"] as bool? ?? false;
+  if (loaded) {
+    RustLib.dispose();
+    _isolateCache.remove("rustLibLoaded");
+  }
+}