timezone-provider: Turn into preloadable

src/provider/preload_manager.py

@@ -7,9 +7,10 @@ from .desktop_provider import desktop_provider
 from .disk_provider import disk_provider
 from .internet_provider import internet_provider
 from .language_provider import language_provider
+from .timezone_provider import timezone_provider
 
-providers = [language_provider, internet_provider,
-             disk_provider, desktop_provider, choices_provider]
+providers = [language_provider, internet_provider, disk_provider,
+             desktop_provider, timezone_provider, choices_provider]
 
 
 class PreloadManager:

src/provider/timezone_provider.py

@@ -1,8 +1,12 @@
 # SPDX-License-Identifier: GPL-3.0-or-later
 
 from time import time
+
 from gi.repository import GnomeDesktop, GObject, GWeather
 
+from .config import config
+from .preloadable import Preloadable
+
 
 class Timezone(GObject.Object):
     __gtype_name__ = __qualname__
@@ -40,18 +44,30 @@ def _recurse_location(location, timezone_map):
             print(f'Developer hint: Unknown timezone {id} {child.get_name()}')
 
 
-### public methods ###
+class TimezoneProvider(Preloadable):
+    def __init__(self):
+        Preloadable.__init__(self, self._get_timezones)
 
-def get_current_timezone():
-    timezone = GnomeDesktop.WallClock().get_timezone()
-    return timezone.get_identifier()
+    def _get_timezones(self):
+        current_timezone = GnomeDesktop.WallClock().get_timezone()
+        config.set('timezone', current_timezone.get_identifier())
+
+        timezone_map = dict()
+        for timezone in GWeather.Location().get_world().get_timezones():
+            id = timezone.get_identifier()
+            timezone_map[id] = Timezone(id)
+
+        for child in _get_location_children(GWeather.Location().get_world()):
+            if not child.has_timezone():  # skips UTC and Etc/GMT+12
+                _recurse_location(child, timezone_map)
+
+        self.timezones = sorted(timezone_map.values(), key=lambda t: t.name)
+
+    ### public methods ###
+
+    def get_timezones(self):
+        self.assert_preloaded()
+        return self.timezones
 
 
-def get_timezones():
-    timezones = {timezone.get_identifier(): Timezone(timezone.get_identifier())
-                 for timezone in GWeather.Location().get_world().get_timezones()}
-    for child in _get_location_children(GWeather.Location().get_world()):
-        if not child.has_timezone():  # skips UTC and Etc/GMT+12
-            _recurse_location(child, timezones)
-
-    return sorted(timezones.values(), key=lambda t: t.name)
+timezone_provider = TimezoneProvider()

src/ui/pages/filter.py

@@ -6,7 +6,7 @@ from gi.repository import Gtk
 from .format_provider import get_formats
 from .global_state import global_state
 from .system_calls import set_system_formats, set_system_timezone
-from .timezone_provider import get_timezones
+from .timezone_provider import timezone_provider
 from .widgets import ProgressRow
 
 
@@ -37,7 +37,7 @@ class FilterPage(Gtk.Box):
                 self.list_model.splice(0, 0, get_formats())
             case FilterType.timezone:
                 self.filter = self._timezone_filter
-                self.list_model.splice(0, 0, get_timezones())
+                self.list_model.splice(0, 0, timezone_provider.get_timezones())
 
         self.search_entry.connect("search-changed", self._filter)
 

src/ui/pages/locale.py

@@ -5,7 +5,6 @@ from gi.repository import Gtk
 from .config import config
 from .format_provider import initialize_formats
 from .global_state import global_state
-from .timezone_provider import get_current_timezone
 
 
 @Gtk.Template(resource_path='/com/github/p3732/os-installer/ui/pages/locale.ui')
@@ -21,10 +20,6 @@ class LocalePage(Gtk.Box):
         if not config.has('formats'):
             initialize_formats()
 
-        if not config.has('timezone'):
-            timezone = get_current_timezone()
-            config.set('timezone', timezone)
-
         config.subscribe('formats', self._update_formats)
         config.subscribe('timezone', self._update_timezone)