Initial LegacyProfileReader plugin implementation

This plugin reads a profile from legacy Cura versions. It hasn't been tested much except that there are no syntax errors. It is currently being blocked by issue 34.

Contributes to issue CURA-37.

plugins/LegacyProfileReader/LegacyProfileReader.py

@@ -0,0 +1,84 @@
+# Copyright (c) 2015 Ultimaker B.V.
+# Cura is released under the terms of the AGPLv3 or higher.
+
+import json #For reading the Dictionary of Doom.
+
+from UM.Application import Application #To get the machine manager to create the new profile in.
+from UM.Settings.Profile import Profile
+from UM.Settings.ProfileReader import ProfileReader
+
+##  A plugin that reads profile data from legacy Cura versions.
+#
+#   It reads a profile from an .ini file, and performs some translations on it.
+#   Not all translations are correct, mind you, but it is a best effort.
+class LegacyProfileReader(ProfileReader):
+    ##  Initialises the legacy profile reader.
+    #
+    #   This does nothing since the only other function is basically stateless.
+    def __init__(self):
+        super().__init__()
+
+    ##  Reads a legacy Cura profile from a file and returns it.
+    #
+    #   \param file_name The file to read the legacy Cura profile from.
+    #   \return The legacy Cura profile that was in the file, if any. If the
+    #   file could not be read or didn't contain a valid profile, \code None
+    #   \endcode is returned.
+    def read(self, file_name):
+        profile = Profile(machine_manager = Application.getInstance().getMachineManager(), read_only = False) #Create an empty profile.
+        profile.setName("Imported Legacy Profile")
+        
+        stream = io.StringIO(serialised) #ConfigParser needs to read from a stream.
+        parser = configparser.ConfigParser(interpolation = None)
+        parser.readfp(stream)
+
+        #Legacy Cura saved the profile under the section "profile_N" where N is the ID of a machine, except when you export in which case it saves it in the section "profile".
+        #Since importing multiple machine profiles is out of scope, just import the first section we find.
+        section = ""
+        for found_section in parser.sections():
+            if found_section.startsWith("profile"):
+                section = found_section
+                break
+        if not section: #No section starting with "profile" was found. Probably not a proper INI file.
+            return None
+        
+        legacy_settings = prepareLocals(parser, section) #Gets the settings from the legacy profile.
+        
+        try:
+            with open(os.path.join(PluginRegistry.getInstance().getPluginPath("LegacyProfileReader"), "DictionaryOfDoom.json"), "r", -1, "utf-8") as f:
+                dict_of_doom = json.load(f) #Parse the Dictionary of Doom.    
+        except IOError as e:
+            Logger.log("e", "Could not open DictionaryOfDoom.json for reading: %s", str(e))
+            return None
+        except Exception as e:
+            Logger.log("e", "Could not parse DictionaryOfDoom.json: %s", str(e))
+            return None
+        
+        if "translations" not in dict_of_doom:
+            Logger.log("e", "Dictionary of Doom has no translations. Is it the correct JSON file?")
+            return None
+        for new_setting, old_setting_expression in dict_of_doom["translations"]: #Evaluate all new settings that would get a value from the translations.
+            compiled = compile(old_setting_expression, new_setting, "eval")
+            new_value = eval(compiled, {}, legacy_settings) #Pass the legacy settings as local variables to allow access to in the evaluation.
+            profile.setSettingValue(new_setting, new_value) #Store the setting in the profile!
+
+        return profile
+    
+    ##  Prepares the local variables that can be used in evaluation of computing
+    #   new setting values from the old ones.
+    #
+    #   This fills a dictionary with all settings from the legacy Cura version
+    #   and their values, so that they can be used in evaluating the new setting
+    #   values as Python code.
+    #
+    #   \param parser The ConfigParser that finds the settings in the legacy
+    #   profile.
+    #   \param section The section in the profile where the settings should be
+    #   found.
+    #   \return A set of local variables, one for each setting in the legacy
+    #   profile.
+    def prepareLocals(self, parser, section):
+        locals = {}
+        for option in parser.options():
+            locals[option] = parser.get(section, option)
+        return locals