Stacks are now loaded from workspace file

CURA-1263

plugins/3MFReader/ThreeMFWorkspaceReader.py

@@ -2,6 +2,9 @@ from UM.Workspace.WorkspaceReader import WorkspaceReader
 from UM.Application import Application
 
 from UM.Logger import Logger
+from UM.Settings.ContainerStack import ContainerStack
+
+import zipfile
 
 ##    Base implementation for reading 3MF workspace files.
 class ThreeMFWorkspaceReader(WorkspaceReader):
@@ -22,4 +25,35 @@ class ThreeMFWorkspaceReader(WorkspaceReader):
         return WorkspaceReader.PreReadResult.accepted
 
     def read(self, file_name):
-        pass
+        # Load all the nodes / meshdata of the workspace
+        nodes = self._3mf_mesh_reader.read(file_name)
+        if nodes is None:
+            nodes = []
+
+
+        archive = zipfile.ZipFile(file_name, "r")
+
+        cura_file_names = [name for name in archive.namelist() if name.startswith("Cura/")]
+
+        # Get the stack(s) saved in the workspace.
+        container_stack_files = [name for name in cura_file_names if name.endswith(".stack.cfg")]
+        global_stack = None
+        extruder_stacks = []
+        for container_stack_file in container_stack_files:
+            container_id = container_stack_file.replace("Cura/", "")
+            container_id = container_id.replace(".stack.cfg", "")
+            stack = ContainerStack(container_id)
+
+            # Serialize stack by converting read data from bytes to string
+            stack.deserialize(archive.open(container_stack_file).read().decode("utf-8"))
+
+            if stack.getMetaDataEntry("type") == "extruder_train":
+                extruder_stacks.append(stack)
+            else:
+                global_stack = stack
+
+        # Check if the right machine type is active now
+        #Application.getInstance().getGlobalContainerStack().getBottom().getId() ==
+
+
+        return nodes