library: Support monitoring external changes to the source file

Revisit after flatpak/xdg-desktop-portal#567

src/gameeky/library/coder.py

@@ -32,6 +32,7 @@
 from .widgets.window import Window
 
 from ..common.logger import logger
+from ..common.monitor import Monitor
 from ..common.utils import bytearray_to_string
 
 
@@ -46,6 +47,7 @@ def __init__(self) -> None:
 
         self._window: Optional[Window] = None
         self._source_path: Optional[str] = None
+        self._monitor = Monitor.default()
 
         self.add_main_option(
             GLib.OPTION_REMAINING,
@@ -61,7 +63,7 @@ def __on_new(self, action: Gio.SimpleAction, data: Optional[Any] = None) -> None
             return
 
         self._window.source = ""
-        self._source_path = None
+        self.source_path = None
 
     def __on_open(self, action: Gio.SimpleAction, data: Optional[Any] = None) -> None:
         default_filter = Gtk.FileFilter()
@@ -86,7 +88,7 @@ def __on_open_finished(
         else:
             path = file.get_path()
             self._window.source = self._do_load(path)
-            self._source_path = path
+            self.source_path = path
 
     def __on_save(self, *args) -> None:
         if self._source_path is None:
@@ -127,7 +129,15 @@ def _do_save(self, path: str) -> None:
             flags=Gio.FileCreateFlags.REPLACE_DESTINATION,
             cancellable=None,
         )
-        self._source_path = path
+        self.source_path = path
+
+    def __on_reload(self, window: Window, data: Optional[Any] = None) -> None:
+        if self._window is None:
+            return
+        if self._source_path is None:
+            return
+
+        self._window.source = self._do_load(self._source_path)
 
     def _do_load(self, path: str) -> str:
         file = Gio.File.new_for_path(path)
@@ -143,8 +153,7 @@ def do_command_line(self, command_line: Gio.ApplicationCommandLine) -> int:
 
         if (source_path := options.get(GLib.OPTION_REMAINING, None)) is not None:
             source_path = bytearray_to_string(source_path[-1])
-
-            self._source_path = source_path
+            self.source_path = source_path
 
         self.activate()
         return 0
@@ -159,6 +168,7 @@ def do_activate(self) -> None:
         )
 
         self._window = Window(application=self)
+        self._window.connect("reload", self.__on_reload)
         self._window.present()
 
         if self._source_path is not None:
@@ -184,8 +194,21 @@ def do_startup(self) -> None:
         self.add_action(save_as_action)
 
     def do_shutdown(self) -> None:
+        self._monitor.shutdown()
         Adw.Application.do_shutdown(self)
 
+    @property
+    def source_path(self) -> Optional[str]:
+        return self._source_path
+
+    @source_path.setter
+    def source_path(self, path: Optional[str]) -> None:
+        self._monitor.shutdown()
+        self._source_path = path
+
+        if self._source_path is not None:
+            self._monitor.add(self._source_path)
+
 
 def main(version: str) -> None:
     application = Application()

src/gameeky/library/widgets/window.py

@@ -22,6 +22,7 @@
 
 from ...common.logger import logger
 from ...common.config import pkgdatadir
+from ...common.monitor import Monitor
 
 
 @Gtk.Template(resource_path="/dev/tchx84/gameeky/library/widgets/window.ui")
@@ -37,6 +38,7 @@ class Window(Adw.ApplicationWindow):
     output_buffer = Gtk.Template.Child()
     execute_button = Gtk.Template.Child()
     stop_button = Gtk.Template.Child()
+    banner = Gtk.Template.Child()
 
     def __init__(self, *args, **kargs) -> None:
         super().__init__(*args, **kargs)
@@ -46,6 +48,8 @@ def __init__(self, *args, **kargs) -> None:
             "changed", self.__on_source_changed
         )
 
+        Monitor.default().connect("changed", self.__on_monitor_changed)
+
     @Gtk.Template.Callback("on_execute_clicked")
     def __on_execute_clicked(self, button: Gtk.Button) -> None:
         self.execute_button.props.visible = False
@@ -155,6 +159,18 @@ def __on_source_changed(
     ) -> None:
         self.emit("changed")
 
+    def __on_monitor_changed(self, monitor: Monitor) -> None:
+        self.banner.props.revealed = True
+
+    @Gtk.Template.Callback("on_reload_clicked")
+    def __on_reload_clicked(
+        self,
+        banner: Adw.Banner,
+        user_data: Optional[Any] = None,
+    ) -> None:
+        self.emit("reload")
+        self.banner.props.revealed = False
+
     @property
     def source(self) -> str:
         return self.source_buffer.props.text

src/gameeky/library/widgets/window.ui

@@ -11,6 +11,13 @@
         <property name="content">
           <object class="GtkBox">
             <property name="orientation">vertical</property>
+            <child>
+              <object class="AdwBanner" id="banner">
+                <property name="button-label" translatable="yes">Reload</property>
+                <property name="title" translatable="yes">Source has been changed on disk</property>
+                <signal name="button-clicked" handler="on_reload_clicked"/>
+              </object>
+            </child>
             <child>
               <object class="GtkScrolledWindow">
                 <child>