Add an AutoSave plugin that autosaves preferences, instances and profiles

Currently using a 1 minute timer, so we do not constantly trigger a save
when editing profiles.

Contributes to CURA-511

plugins/AutoSave/AutoSave.py

@@ -0,0 +1,77 @@
+# Copyright (c) 2016 Ultimaker B.V.
+# Cura is released under the terms of the AGPLv3 or higher.
+
+from PyQt5.QtCore import QTimer
+
+from UM.Extension import Extension
+from UM.Preferences import Preferences
+from UM.Application import Application
+from UM.Resources import Resources
+from UM.Logger import Logger
+
+class AutoSave(Extension):
+    def __init__(self):
+        super().__init__()
+
+        Preferences.getInstance().preferenceChanged.connect(self._onPreferenceChanged)
+
+        machine_manager = Application.getInstance().getMachineManager()
+
+        self._profile = None
+        machine_manager.activeProfileChanged.connect(self._onActiveProfileChanged)
+        machine_manager.profileNameChanged.connect(self._onProfilesChanged)
+        machine_manager.profilesChanged.connect(self._onProfilesChanged)
+        machine_manager.machineInstanceNameChanged.connect(self._onInstancesChanged)
+        machine_manager.machineInstancesChanged.connect(self._onInstancesChanged)
+        Application
+        self._onActiveProfileChanged()
+
+        self._change_timer = QTimer()
+        self._change_timer.setInterval(1000 * 60)
+        self._change_timer.setSingleShot(True)
+        self._change_timer.timeout.connect(self._onTimeout)
+
+        self._save_preferences = False
+        self._save_profiles = False
+        self._save_instances = False
+
+    def _onPreferenceChanged(self, preference):
+        self._save_preferences = True
+        self._change_timer.start()
+
+    def _onSettingValueChanged(self, setting):
+        self._save_profiles = True
+        self._change_timer.start()
+
+    def _onActiveProfileChanged(self):
+        if self._profile:
+            self._profile.settingValueChanged.disconnect(self._onSettingValueChanged)
+
+        self._profile = Application.getInstance().getMachineManager().getActiveProfile()
+
+        if self._profile:
+            self._profile.settingValueChanged.connect(self._onSettingValueChanged)
+
+    def _onProfilesChanged(self):
+        self._save_profiles = True
+        self._change_timer.start()
+
+    def _onInstancesChanged(self):
+        self._save_instances = True
+        self._change_timer.start()
+
+    def _onTimeout(self):
+        Logger.log("d", "Autosaving preferences, instances and profiles")
+
+        if self._save_preferences:
+            Preferences.getInstance().writeToFile(Resources.getStoragePath(Resources.Preferences, Application.getInstance().getApplicationName() + ".cfg"))
+
+        if self._save_instances:
+            Application.getInstance().getMachineManager().saveMachineInstances()
+
+        if self._save_profiles:
+            Application.getInstance().getMachineManager().saveProfiles()
+
+        self._save_preferences = False
+        self._save_instances = False
+        self._save_profiles = False