Cleaner code

I was hoping to completely nix the generic materials model (since it's basically just a brand "Generic", but then in the QML it has to be have the same in terms of sub-menus or fold-outs and that looked stupid (Generic -> ABS -> ABS)). So we keep that one for now. It is cleaner though.

Contributes to CURA-5162, CURA-5378

cura/Machines/Models/BaseMaterialsModel.py

@@ -2,51 +2,54 @@
 # Cura is released under the terms of the LGPLv3 or higher.
 
 from PyQt5.QtCore import Qt, pyqtSignal, pyqtProperty
-
-from UM.Application import Application
 from UM.Qt.ListModel import ListModel
 
 
-#
-# This is the base model class for GenericMaterialsModel and BrandMaterialsModel
-# Those 2 models are used by the material drop down menu to show generic materials and branded materials separately.
-# The extruder position defined here is being used to bound a menu to the correct extruder. This is used in the top
-# bar menu "Settings" -> "Extruder nr" -> "Material" -> this menu
-#
+## This is the base model class for GenericMaterialsModel and MaterialBrandsModel.
+#  Those 2 models are used by the material drop down menu to show generic materials and branded materials separately.
+#  The extruder position defined here is being used to bound a menu to the correct extruder. This is used in the top
+#  bar menu "Settings" -> "Extruder nr" -> "Material" -> this menu
 class BaseMaterialsModel(ListModel):
-    RootMaterialIdRole = Qt.UserRole + 1
-    IdRole = Qt.UserRole + 2
-    NameRole = Qt.UserRole + 3
-    BrandRole = Qt.UserRole + 4
-    MaterialRole = Qt.UserRole + 5
-    ColorRole = Qt.UserRole + 6
-    ContainerNodeRole = Qt.UserRole + 7
-    ColorCodeRole = Qt.UserRole + 8
-    GUIDRole = Qt.UserRole + 9
-    IsFavoriteRole = Qt.UserRole + 10
 
     extruderPositionChanged = pyqtSignal()
 
     def __init__(self, parent = None):
         super().__init__(parent)
-        self._application = Application.getInstance()
-        self._machine_manager = self._application.getMachineManager()
 
-        self.addRoleName(self.RootMaterialIdRole, "root_material_id")
-        self.addRoleName(self.IdRole, "id")
-        self.addRoleName(self.GUIDRole, "GUID")
-        self.addRoleName(self.NameRole, "name")
-        self.addRoleName(self.BrandRole, "brand")
-        self.addRoleName(self.MaterialRole, "material")
-        self.addRoleName(self.ColorRole, "color_name")
-        self.addRoleName(self.ColorCodeRole, "color_code")
-        self.addRoleName(self.ContainerNodeRole, "container_node")
-        self.addRoleName(self.IsFavoriteRole, "is_favorite")
+        from cura.CuraApplication import CuraApplication
+
+        self._application = CuraApplication.getInstance()
+
+        # Make these managers available to all material models
+        self._extruder_manager = self._application.getExtruderManager()
+        self._machine_manager = self._application.getMachineManager()
+        self._material_manager = self._application.getMaterialManager()
+
+        # Update the stack and the model data when the machine changes
+        self._machine_manager.globalContainerChanged.connect(self._updateExtruderStack)
+
+        # Update this model when switching machines
+        self._machine_manager.activeStackChanged.connect(self._update)
+        
+        # Update this model when list of materials changes
+        self._material_manager.materialsUpdated.connect(self._update)
+
+        self.addRoleName(Qt.UserRole + 1, "root_material_id")
+        self.addRoleName(Qt.UserRole + 2, "id")
+        self.addRoleName(Qt.UserRole + 3, "GUID")
+        self.addRoleName(Qt.UserRole + 4, "name")
+        self.addRoleName(Qt.UserRole + 5, "brand")
+        self.addRoleName(Qt.UserRole + 6, "material")
+        self.addRoleName(Qt.UserRole + 7, "color_name")
+        self.addRoleName(Qt.UserRole + 8, "color_code")
+        self.addRoleName(Qt.UserRole + 9, "container_node")
+        self.addRoleName(Qt.UserRole + 10, "is_favorite")
 
         self._extruder_position = 0
         self._extruder_stack = None
-        # Update the stack and the model data when the machine changes
-        self._machine_manager.globalContainerChanged.connect(self._updateExtruderStack)
+
+        self._available_materials = None
+        self._favorite_ids = None
 
     def _updateExtruderStack(self):
         global_stack = self._machine_manager.activeMachine
@@ -71,8 +74,30 @@ class BaseMaterialsModel(ListModel):
     def extruderPosition(self) -> int:
         return self._extruder_position
 
-    #
-    # This is an abstract method that needs to be implemented by
-    #
+    ## This is an abstract method that needs to be implemented by the specific
+    #  models themselves.
     def _update(self):
         pass
+
+    ## This method is used by all material models in the beginning of the
+    #  _update() method in order to prevent errors. It's the same in all models
+    #  so it's placed here for easy access.
+    def _canUpdate(self):
+        global_stack = self._machine_manager.activeMachine
+
+        if global_stack is None:
+            return False
+
+        extruder_position = str(self._extruder_position)
+
+        if extruder_position not in global_stack.extruders:
+            return False
+        
+        extruder_stack = global_stack.extruders[extruder_position]
+
+        self._available_materials = self._material_manager.getAvailableMaterialsForMachineExtruder(global_stack, extruder_stack)
+        if self._available_materials is None:
+            return False
+
+        return True
+