Migration code for the new database format

autojump

@@ -76,9 +76,8 @@ def open_dic(dic_file, error_recovery=False):
     """Try hard to open the database file, recovering
        from backup if needed. """
     try:
-        aj_file = open(dic_file, 'r')
         path_dict = {}
-        with aj_file:
+        with open(dic_file, 'r') as aj_file:
             for l in aj_file.readlines():
                 weight,path = l[:-1].split("\t",1)
                 path_dict[path] = float(weight)
@@ -90,7 +89,27 @@ def open_dic(dic_file, error_recovery=False):
             import shutil
             shutil.copy(dic_file+".bak", dic_file)
             return open_dic(dic_file, True)
-        else: return {} #if everything fails, return an empty file
+        else:
+            # Temporary migration code
+            old_dic_file = get_dic_file("autojump_py")
+            if os.path.exists(old_dic_file):
+                try: # fix to get optimised pickle in python < 3
+                    import cPickle as pickle
+                except ImportError:
+                    import pickle
+                try:
+                    with open(old_dic_file, 'rb') as aj_file:
+                        if version_info[0] > 2:
+                            #encoding is only specified for python2.x compatibility
+                            path_dict = pickle.load(aj_file, encoding="utf-8")
+                        else:
+                            path_dict = pickle.load(aj_file)
+                        aj_file.close()
+                        return path_dict
+                except (IOError, EOFError, pickle.UnpicklingError):
+                    pass
+            return {} #if everything fails, return an empty file
+
 
 def forget(path_dict, dic_file):
     """Gradually forget about directories. Only call
@@ -156,8 +175,7 @@ def find_matches(dirs, patterns, result_list, ignore_case, max_matches):
             if len(result_list) >= max_matches :
                 break
 
-def get_dic_file():
-    filename = "autojump.txt"
+def get_dic_file(filename="autojump.txt"):
     if CONFIG_DIR == os.path.expanduser("~"):
         dic_file = CONFIG_DIR+"/." + filename
     else: