From 847d6429d0f901f4cb00a63521a897e27cb1efda Mon Sep 17 00:00:00 2001
From: fieldOfView <aldo@fieldofview.com>
Date: Thu, 15 Sep 2016 18:53:16 +0200
Subject: [PATCH] Speed up switching between multiextrusion machines

ExtruderManager.addMachineExtruders is supposed to create a cache, but this cache was always rebuilt because of an indentation error.
---
 cura/Settings/ExtruderManager.py | 13 +++++++++++--
 cura/Settings/ExtrudersModel.py  |  2 +-
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/cura/Settings/ExtruderManager.py b/cura/Settings/ExtruderManager.py
index 72fdebc99d..e9f2404ed7 100644
--- a/cura/Settings/ExtruderManager.py
+++ b/cura/Settings/ExtruderManager.py
@@ -13,9 +13,13 @@ import UM.Settings.SettingFunction
 #
 #   This keeps a list of extruder stacks for each machine.
 class ExtruderManager(QObject):
-    ##  Signal to notify other components when the list of extruders changes.
+    ##  Signal to notify other components when the list of extruders for a machine definition changes.
     extrudersChanged = pyqtSignal(QVariant)
 
+    ## Signal to notify other components when the global container stack is switched to a definition
+    #  that has different extruders than the previous global container stack
+    globalContainerStackDefinitionChanged = pyqtSignal()
+
     ##  Notify when the user switches the currently active extruder.
     activeExtruderChanged = pyqtSignal()
 
@@ -25,6 +29,7 @@ class ExtruderManager(QObject):
         self._extruder_trains = { } #Per machine, a dictionary of extruder container stack IDs.
         self._active_extruder_index = 0
         UM.Application.getInstance().globalContainerStackChanged.connect(self.__globalContainerStackChanged)
+        self._global_container_stack_definition_id = None
         self._addCurrentMachineExtruders()
 
     ##  Gets the unique identifier of the currently active extruder stack.
@@ -141,7 +146,7 @@ class ExtruderManager(QObject):
                     shallow_stack = UM.Settings.ContainerStack(machine_id + "_shallow")
                     shallow_stack.addContainer(machine_definition)
                     extruder_train.setNextStack(shallow_stack)
-                changed = True
+                    changed = True
         if changed:
             self.extrudersChanged.emit(machine_id)
 
@@ -301,6 +306,10 @@ class ExtruderManager(QObject):
 
     def __globalContainerStackChanged(self):
         self._addCurrentMachineExtruders()
+        global_container_stack = UM.Application.getInstance().getGlobalContainerStack()
+        if global_container_stack and global_container_stack.getBottom() and global_container_stack.getBottom().getId() != self._global_container_stack_definition_id:
+            self._global_container_stack_definition_id = global_container_stack.getBottom().getId()
+            self.globalContainerStackDefinitionChanged.emit()
         self.activeExtruderChanged.emit()
 
     ##  Adds the extruders of the currently active machine.
diff --git a/cura/Settings/ExtrudersModel.py b/cura/Settings/ExtrudersModel.py
index 0ba6cdcfd6..c5a8160bf4 100644
--- a/cura/Settings/ExtrudersModel.py
+++ b/cura/Settings/ExtrudersModel.py
@@ -52,7 +52,7 @@ class ExtrudersModel(UM.Qt.ListModel.ListModel):
 
         #Listen to changes.
         manager = ExtruderManager.getInstance()
-        manager.extrudersChanged.connect(self._updateExtruders) #When the list of extruders changes in general.
+        manager.globalContainerStackDefinitionChanged.connect(self._updateExtruders) #When the global stack changes to a printer with different extruders.
 
         self._updateExtruders()