Introduce a CuraStackBuilder class

It contains factory functions for creating new stacks with certain
quality/material/variant combinations.

cura/Settings/CuraStackBuilder.py

@@ -0,0 +1,86 @@
+# Copyright (c) 2017 Ultimaker B.V.
+# Cura is released under the terms of the AGPLv3 or higher.
+
+from UM.Settings.DefinitionContainer import DefinitionContainer
+from UM.Settings.InstanceContainer import InstanceContainer
+from UM.Settings.ContainerRegistry import ContainerRegistry
+
+from .GlobalStack import GlobalStack
+from .ExtruderStack import ExtruderStack
+
+class CuraStackBuilder:
+    @staticmethod
+    def createExtruderStack(new_stack_id: str, definition_id: str, **kwargs) -> ExtruderStack:
+        registry = ContainerRegistry.getInstance()
+
+        stack = ExtruderStack(new_stack_id)
+
+        user_container = InstanceContainer(new_stack_id + "_user")
+        user_container.addMetaDataEntry("type", "user")
+        user_container.addMetaDataEntry("machine", new_stack_id)
+
+        stack.setUserChanges(user_container)
+
+        if "quality_changes" in kwargs:
+            stack.setQualityChangesById(kwargs["quality_changes"])
+
+        if "quality" in kwargs:
+            stack.setQualityById(kwargs["quality"])
+
+        if "material" in kwargs:
+            stack.setMaterialById(kwargs["material"])
+
+        if "variant" in kwargs:
+            stack.setVariantById(kwargs["variant"])
+
+        if "definition_changes" in kwargs:
+            stack.setDefinitionChangesById(kwargs["definition_changes"])
+
+        if "definition" in kwargs:
+            stack.setDefinitionById(kwargs["definition"])
+
+        if "next_stack" in kwargs:
+            stack.setNextStack(kwargs["next_stack"])
+
+        # Only add the created containers to the registry after we have set all the other
+        # properties. This makes the create operation more transactional, since any problems
+        # setting properties will not result in incomplete containers being added.
+        registry.addContainer(stack)
+        registry.addContainer(user_container)
+
+        return stack
+
+    @staticmethod
+    def createGlobalStack(new_stack_id: str, definition: DefinitionContainer, **kwargs) -> GlobalStack:
+        registry = ContainerRegistry.getInstance()
+
+        stack = GlobalStack(new_stack_id)
+
+        stack.setDefinition(definition)
+
+        user_container = InstanceContainer(new_stack_id + "_user")
+        user_container.addMetaDataEntry("type", "user")
+        user_container.addMetaDataEntry("machine", new_stack_id)
+        user_container.setDefinition(definition)
+
+        stack.setUserChanges(user_container)
+
+        if "quality_changes" in kwargs:
+            stack.setQualityChangesById(kwargs["quality_changes"])
+
+        if "quality" in kwargs:
+            stack.setQualityById(kwargs["quality"])
+
+        if "material" in kwargs:
+            stack.setMaterialById(kwargs["material"])
+
+        if "variant" in kwargs:
+            stack.setVariantById(kwargs["variant"])
+
+        if "definition_changes" in kwargs:
+            stack.setDefinitionChangesById(kwargs["definition_changes"])
+
+        registry.addContainer(stack)
+        registry.addContainer(user_container)
+
+        return stack