From d95e634aa7bcf8018797923c1d90fc2eadff8ce9 Mon Sep 17 00:00:00 2001
From: Abhilash Raj
Date: Fri, 5 Sep 2014 10:42:52 +0530
Subject: add new UUID type

---
 src/mailman/database/types.py | 108 +++++++++++++++++++++++++++++++++---------
 1 file changed, 85 insertions(+), 23 deletions(-)

(limited to 'src/mailman/database/types.py')

diff --git a/src/mailman/database/types.py b/src/mailman/database/types.py
index ba3d92df4..5ffbf3965 100644
--- a/src/mailman/database/types.py
+++ b/src/mailman/database/types.py
@@ -23,43 +23,105 @@ from __future__ import absolute_import, print_function, unicode_literals
 __metaclass__ = type
 __all__ = [
     'Enum',
+    'UUID'
     ]
 
+import uuid
 
-from storm.properties import SimpleProperty
-from storm.variables import Variable
+from sqlalchemy.types import TypeDecorator, BINARY, CHAR
+from sqlalchemy.dailects import postgresql
 
 
 
-class _EnumVariable(Variable):
-    """Storm variable for supporting enum types.
+class Enum(TypeDecorator):
+    """
+    Stores an integer-based Enum as an integer in the database, and converts it
+    on-the-fly.
+    """
+
+    impl = Integer
+
+    def __init__(self, *args, **kw):
+        self.enum = kw.pop("enum")
+        TypeDecorator.__init__(self, *args, **kw)
+
+    def process_bind_param(self, value, dialect):
+        if not isinstance(value, self.enum):
+            raise ValueError("{} must be a value of the {} enum".format(
+                             self.value, self.enum.__name__))
+        return value.value
+
 
-    To use this, make the database column a INTEGER.
+    def process_result_value(self, value, dialect):
+        return self.enum(value)
+
+
+
+class UUID(TypeDecorator):
     """
+    Stores a UUID in the database natively when it can and falls back to
+    a BINARY(16) or a CHAR(32) when it can't.
 
-    def __init__(self, *args, **kws):
-        self._enum = kws.pop('enum')
-        super(_EnumVariable, self).__init__(*args, **kws)
+    ::
 
-    def parse_set(self, value, from_db):
-        if value is None:
-            return None
-        if not from_db:
-            return value
-        return self._enum(value)
+        from sqlalchemy_utils import UUIDType
+        import uuid
+
+        class User(Base):
+            __tablename__ = 'user'
 
-    def parse_get(self, value, to_db):
+            # Pass `binary=False` to fallback to CHAR instead of BINARY
+            id = sa.Column(UUIDType(binary=False), primary_key=True)
+    """
+    impl = BINARY(16)
+
+    python_type = uuid.UUID
+
+    def __init__(self, binary=True, native=True):
+        """
+        :param binary: Whether to use a BINARY(16) or CHAR(32) fallback.
+        """
+        self.binary = binary
+        self.native = native
+
+    def load_dialect_impl(self, dialect):
+        if dialect.name == 'postgresql' and self.native:
+            # Use the native UUID type.
+            return dialect.type_descriptor(postgresql.UUID())
+
+        else:
+            # Fallback to either a BINARY or a CHAR.
+            kind = self.impl if self.binary else CHAR(32)
+            return dialect.type_descriptor(kind)
+
+    @staticmethod
+    def _coerce(value):
+        if value and not isinstance(value, uuid.UUID):
+            try:
+                value = uuid.UUID(value)
+
+            except (TypeError, ValueError):
+                value = uuid.UUID(bytes=value)
+
+        return value
+
+    def process_bind_param(self, value, dialect):
         if value is None:
-            return None
-        if not to_db:
             return value
-        return value.value
 
+        if not isinstance(value, uuid.UUID):
+            value = self._coerce(value)
+
+        if self.native and dialect.name == 'postgresql':
+            return str(value)
 
-class Enum(SimpleProperty):
-    """Custom type for Storm supporting enums."""
+        return value.bytes if self.binary else value.hex
+
+    def process_result_value(self, value, dialect):
+        if value is None:
+            return value
 
-    variable_class = _EnumVariable
+        if self.native and dialect.name == 'postgresql':
+            return uuid.UUID(value)
 
-    def __init__(self, enum=None):
-        super(Enum, self).__init__(enum=enum)
+        return uuid.UUID(bytes=value) if self.binary else uuid.UUID(value)
-- 
cgit v1.2.3-70-g09d2