Implement getCfgVersion

Mostly copied from the implementation in the 3.0 to 3.1 upgrade.

Contributes to issue CURA-5054.

plugins/VersionUpgrade/VersionUpgrade32to33/VersionUpgrade32to33.py

@@ -9,9 +9,23 @@ from UM.VersionUpgrade import VersionUpgrade #We're inheriting from this.
 ##  Upgrades configurations from the state they were in at version 3.2 to the
 #   state they should be in at version 3.3.
 class VersionUpgrade32to33(VersionUpgrade):
-    ##  Gets the version number from a CFG file.
-    def getCfgVersion(self, serialized):
-        raise NotImplementedError("This has not yet been implemented.")
+    ##  Gets the version number from a CFG file in Uranium's 3.2 format.
+    #
+    #   Since the format may change, this is implemented for the 3.2 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):
+        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 a quality container to the new format.
     def upgradeQuality(self, serialized, filename):