Recursive watch folders for reloading, --debug

Watching folders will only be done if --debug is provided, to avoid
filesystem scan slowdowns and over watch limit errors.

harmonyqml/__init__.py

@@ -11,6 +11,12 @@ from .engine import Engine
 
 
 def run() -> None:
+    try:
+        sys.argv.index("--debug")
+        debug = True
+    except ValueError:
+        debug = False
+
     app    = QGuiApplication(sys.argv)
-    engine = Engine(app)
+    engine = Engine(app, debug=debug)
     engine.show_window()

harmonyqml/engine.py

@@ -4,7 +4,7 @@
 import logging
 import sys
 from pathlib import Path
-from typing import Optional
+from typing import Generator, Optional
 
 from PyQt5.QtCore import QFileSystemWatcher, QObject, QTimer
 from PyQt5.QtGui import QGuiApplication
@@ -17,8 +17,10 @@ from .backend import DummyBackend
 
 
 class Engine(QQmlApplicationEngine):
-    def __init__(self, app: QGuiApplication, parent: Optional[QObject] = None
-                ) -> None:
+    def __init__(self,
+                 app: QGuiApplication,
+                 debug:  bool              = False,
+                 parent: Optional[QObject] = None) -> None:
         super().__init__(parent)
         self.app     = app
         self.backend = DummyBackend()
@@ -37,9 +39,13 @@ class Engine(QQmlApplicationEngine):
         self._sigint_timer.start(100)
 
         # Setup UI live-reloading when a file is edited
-        self.file_watcher = QFileSystemWatcher()
-        self.file_watcher.directoryChanged.connect(lambda _: self.reload_qml())
-        self.file_watcher.addPath(str(self.app_dir / "components"))
+        if debug:
+            self._watcher = QFileSystemWatcher()
+            self._watcher.directoryChanged.connect(lambda _: self.reload_qml())
+            self._watcher.addPath(str(self.app_dir))
+
+            for _dir in list(self._recursive_dirs_in(self.app_dir)):
+                self._watcher.addPath(str(_dir))
 
         # Load QML page and show window
         self.load(str(self.app_dir / "components" / "Window.qml"))
@@ -50,6 +56,13 @@ class Engine(QQmlApplicationEngine):
         sys.exit(self.app.exec())
 
 
+    def _recursive_dirs_in(self, path: Path) -> Generator[Path, None, None]:
+        for item in path.iterdir():
+            if item.is_dir() and item.name != "__pycache__":
+                yield item
+                yield from self._recursive_dirs_in(item)
+
+
     def reload_qml(self) -> None:
         self.clearComponentCache()
         loader = self.rootObjects()[0].findChild(QObject, "UILoader")