Add version upgrade 4.1 to 4.2

CURA-6460

plugins/VersionUpgrade/VersionUpgrade41to42/VersionUpgrade41to42.py

@@ -0,0 +1,79 @@
+# Copyright (c) 2019 Ultimaker B.V.
+# Cura is released under the terms of the LGPLv3 or higher.
+
+import configparser
+import io
+from typing import List, Tuple
+
+from UM.VersionUpgrade import VersionUpgrade
+
+_REMOVED_SETTING_KEYS = ["prime_tower_circular"]  # type: List[str]
+
+
+##  Upgrades configurations from the state they were in at version 4.0 to the
+#   state they should be in at version 4.2.
+class VersionUpgrade41to42(VersionUpgrade):
+    ##  Gets the version number from a CFG file in Uranium's 4.0 format.
+    #
+    #   Since the format may change, this is implemented for the 4.0 format only
+    #   and needs to be included in the version upgrade system rather than
+    #   globally in Uranium.
+    #
+    #   \param serialised The serialised form of a CFG file.
+    #   \return The version number stored in the CFG file.
+    #   \raises ValueError The format of the version number in the file is
+    #   incorrect.
+    #   \raises KeyError The format of the file is incorrect.
+    def getCfgVersion(self, serialised: str) -> int:
+        parser = configparser.ConfigParser(interpolation = None)
+        parser.read_string(serialised)
+        format_version = int(parser.get("general", "version")) #Explicitly give an exception when this fails. That means that the file format is not recognised.
+        setting_version = int(parser.get("metadata", "setting_version", fallback = "0"))
+        return format_version * 1000000 + setting_version
+
+    ##  Upgrades instance containers to have the new version
+    #   number.
+    def upgradeInstanceContainer(self, serialized: str, filename: str) -> Tuple[List[str], List[str]]:
+        parser = configparser.ConfigParser(interpolation = None)
+        parser.read_string(serialized)
+
+        # Update version number.
+        parser["general"]["version"] = "4"
+        parser["metadata"]["setting_version"] = "8"
+
+        if "values" in parser:
+            for key in _REMOVED_SETTING_KEYS:
+                if key in parser["values"]:
+                    del parser["values"][key]
+
+        result = io.StringIO()
+        parser.write(result)
+        return [filename], [result.getvalue()]
+
+    ##  Upgrades Preferences to have the new version number.
+    def upgradePreferences(self, serialized: str, filename: str) -> Tuple[List[str], List[str]]:
+        parser = configparser.ConfigParser(interpolation = None)
+        parser.read_string(serialized)
+
+        # Update version number.
+        parser["general"]["version"] = "6"
+        if "metadata" not in parser:
+            parser["metadata"] = {}
+        parser["metadata"]["setting_version"] = "8"
+
+        result = io.StringIO()
+        parser.write(result)
+        return [filename], [result.getvalue()]
+
+    ##  Upgrades stacks to have the new version number.
+    def upgradeStack(self, serialized: str, filename: str) -> Tuple[List[str], List[str]]:
+        parser = configparser.ConfigParser(interpolation = None)
+        parser.read_string(serialized)
+
+        # Update version number.
+        parser["general"]["version"] = "4"
+        parser["metadata"]["setting_version"] = "8"
+
+        result = io.StringIO()
+        parser.write(result)
+        return [filename], [result.getvalue()]