Allow registering hooks.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>

lib/newfol/filemanip.py

@@ -554,6 +554,13 @@ class FileStorage:
         "yaml": YAMLFile,
         "raw": RawFile
     }
+    HOOKS = {
+        "git": GitHook,
+        "sha256": lambda *a, **k: HashHook("sha256", *a, **k),
+        "sha384": lambda *a, **k: HashHook("sha384", *a, **k),
+        "sha512": lambda *a, **k: HashHook("sha512", *a, **k),
+        "hash": lambda *a, **k: HashHook(None, *a, **k),
+    }
 
     def __init__(self, fmt, filename, txnformat=None, options=None):
         txnformat = self._canonicalize_transaction_types(txnformat)
@@ -574,6 +581,17 @@ class FileStorage:
         except KeyError:
             pass
 
+    @classmethod
+    def register_hook(klass, name, obj):
+        klass.HOOKS[name] = obj
+
+    @classmethod
+    def unregister_hook(klass, name):
+        try:
+            del klass.HOOKS[name]
+        except KeyError:
+            pass
+
     @staticmethod
     def _canonicalize_transaction_types(types):
         if types is None:
@@ -586,23 +604,13 @@ class FileStorage:
             stypes.discard("hash")
         return list(filter(lambda x: x in stypes, types))
 
-    @staticmethod
-    def _get_transaction_types():
-        return {
-            "git": GitHook,
-            "sha256": lambda *a, **k: HashHook("sha256", *a, **k),
-            "sha384": lambda *a, **k: HashHook("sha384", *a, **k),
-            "sha512": lambda *a, **k: HashHook("sha512", *a, **k),
-            "hash": lambda *a, **k: HashHook(None, *a, **k),
-        }
-
     @staticmethod
     def transaction_types():
-        return list(sorted(FileStorage._get_transaction_types().keys()))
+        return list(sorted(FileStorage.HOOKS.keys()))
 
     @staticmethod
     def _make_transaction_store(items, options):
-        txntypes = FileStorage._get_transaction_types()
+        txntypes = FileStorage.HOOKS
         if items is None or items == "":
             return Hook()
         elif isinstance(items, str):