Separate quality manager related classes into separate files

cura/Machines/QualityGroup.py

@@ -0,0 +1,51 @@
+# Copyright (c) 2018 Ultimaker B.V.
+# Cura is released under the terms of the LGPLv3 or higher.
+
+from typing import Optional, List
+
+from PyQt5.QtCore import QObject, pyqtSlot
+
+
+#
+# A QualityGroup represents a group of containers that must be applied to each ContainerStack when it's used.
+# Some concrete examples are Quality and QualityChanges: when we select quality type "normal", this quality type
+# must be applied to all stacks in a machine, although each stack can have different containers. Use an Ultimaker 3
+# as an example, suppose we choose quality type "normal", the actual InstanceContainers on each stack may look
+# as below:
+#                       GlobalStack         ExtruderStack 1         ExtruderStack 2
+# quality container:    um3_global_normal   um3_aa04_pla_normal     um3_aa04_abs_normal
+#
+# This QualityGroup is mainly used in quality and quality_changes to group the containers that can be applied to
+# a machine, so when a quality/custom quality is selected, the container can be directly applied to each stack instead
+# of looking them up again.
+#
+class QualityGroup(QObject):
+
+    def __init__(self, name: str, quality_type: str, parent = None):
+        super().__init__(parent)
+        self.name = name
+        self.node_for_global = None  # type: Optional["QualityGroup"]
+        self.nodes_for_extruders = dict()  # position str -> QualityGroup
+        self.quality_type = quality_type
+        self.is_available = False
+
+    @pyqtSlot(result = str)
+    def getName(self) -> str:
+        return self.name
+
+    def getAllKeys(self) -> set:
+        result = set()
+        for node in [self.node_for_global] + list(self.nodes_for_extruders.values()):
+            if node is None:
+                continue
+            for key in node.getContainer().getAllKeys():
+                result.add(key)
+        return result
+
+    def getAllNodes(self) -> List["QualityGroup"]:
+        result = []
+        if self.node_for_global is not None:
+            result.append(self.node_for_global)
+        for extruder_node in self.nodes_for_extruders.values():
+            result.append(extruder_node)
+        return result