From 6db26eaca5053c5cabace4000a268fa0113b11a3 Mon Sep 17 00:00:00 2001
From: Lipu Fei <lipu.fei815@gmail.com>
Date: Sat, 3 Mar 2018 15:29:49 +0100
Subject: [PATCH] Add getDefaultMaterial() in MaterialManager

---
 cura/Machines/MaterialManager.py  | 23 +++++++++++++++++++++--
 cura/Settings/CuraStackBuilder.py | 15 ++-------------
 2 files changed, 23 insertions(+), 15 deletions(-)

diff --git a/cura/Machines/MaterialManager.py b/cura/Machines/MaterialManager.py
index 5998e8b020..98e4f67f82 100644
--- a/cura/Machines/MaterialManager.py
+++ b/cura/Machines/MaterialManager.py
@@ -4,17 +4,22 @@
 from collections import defaultdict, OrderedDict
 import copy
 import uuid
-from typing import Optional
+from typing import Optional, TYPE_CHECKING
 
 from PyQt5.Qt import QTimer, QObject, pyqtSignal, pyqtSlot
 
 from UM.Application import Application
 from UM.Logger import Logger
-from UM.Settings import ContainerRegistry
+from UM.Settings.ContainerRegistry import ContainerRegistry
+from UM.Settings.SettingFunction import SettingFunction
+from UM.Util import parseBool
 
 from .MaterialNode import MaterialNode
 from .MaterialGroup import MaterialGroup
 
+if TYPE_CHECKING:
+    from cura.Settings.GlobalStack import GlobalStack
+
 
 #
 # MaterialManager maintains a number of maps and trees for material lookup.
@@ -344,6 +349,20 @@ class MaterialManager(QObject):
         else:
             return None
 
+    def getDefaultMaterial(self, global_stack: "GlobalStack", extruder_variant_name: str) -> Optional["MaterialNode"]:
+        node = None
+        machine_definition = global_stack.definition
+        if parseBool(machine_definition.getMetaDataEntry("has_materials", False)):
+            material_diameter = machine_definition.getProperty("material_diameter", "value")
+            if isinstance(material_diameter, SettingFunction):
+                material_diameter = material_diameter(global_stack)
+            approximate_material_diameter = str(round(material_diameter))
+            root_material_id = machine_definition.getMetaDataEntry("preferred_material")
+            root_material_id = self.getRootMaterialIDForDiameter(root_material_id, approximate_material_diameter)
+            node = self.getMaterialNode(machine_definition.getId(), extruder_variant_name,
+                                        material_diameter, root_material_id)
+        return node
+
     #
     # Methods for GUI
     #
diff --git a/cura/Settings/CuraStackBuilder.py b/cura/Settings/CuraStackBuilder.py
index efdfa677fc..a8234b9de9 100644
--- a/cura/Settings/CuraStackBuilder.py
+++ b/cura/Settings/CuraStackBuilder.py
@@ -71,19 +71,8 @@ class CuraStackBuilder:
 
         # get material container for extruders
         material_container = application.empty_material_container
-        # Only look for the preferred material if this machine has materials
-        if parseBool(machine_definition.getMetaDataEntry("has_materials", False)):
-            material_diameter = machine_definition.getProperty("material_diameter", "value")
-            if isinstance(material_diameter, SettingFunction):
-                material_diameter = material_diameter(new_global_stack)
-            approximate_material_diameter = str(round(material_diameter))
-            root_material_id = machine_definition.getMetaDataEntry("preferred_material")
-            root_material_id = material_manager.getRootMaterialIDForDiameter(root_material_id, approximate_material_diameter)
-            material_node = material_manager.getMaterialNode(definition_id, extruder_variant_name, material_diameter, root_material_id)
-            # Sanity check. If you see this error, the related definition files should be fixed.
-            if not material_node:
-                raise RuntimeError("Cannot find material with definition [%s], extruder_variant_name [%s], and root_material_id [%s]" %
-                                   (definition_id, extruder_variant_name, root_material_id))
+        material_node = material_manager.getDefaultMaterial(new_global_stack, extruder_variant_name)
+        if material_node:
             material_container = material_node.getContainer()
 
         # Create ExtruderStacks