NPO-Accounting/conservancy_beancount Changeset - b880115774ac

Changeset - b880115774ac

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Brett Smith - 3 years ago 2021-03-15 17:40:09
brettcsmith@brettcsmith.org

query: Refactor DBColumn.

Avoid an issubclass check on every call, and make it easier for subclasses
to override part of the call implementation.

1 file changed with 15 insertions and 5 deletions:

conservancy_beancount/reports/query.py

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conservancy_beancount/reports/query.py

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@@ ... / @@ -169,12 +169,19 @@ class DBColumn(bc_query_compile.EvalColumn): @@
     _db_cursor: ClassVar[sqlite3.Cursor]
     _db_query: ClassVar[str]
     _dtype: ClassVar[Type] = set
     _return: ClassVar[Callable[['DBColumn'], object]]
     __intypes__ = [Posting]
     @classmethod
     def with_db(cls, connection: sqlite3.Connection) -> Type['DBColumn']:
         return type(cls.__name__, (cls,), {'_db_cursor': connection.cursor()})
     def __init_subclass__(cls) -> None:
         if issubclass(cls._dtype, set):
             cls._return = cls._return_set
         else:
             cls._return = cls._return_scalar
     def __init__(self, colname: Optional[str]=None) -> None:
         if not hasattr(self, '_db_cursor'):
             if colname is None:
@@ ... / @@ -186,14 +193,17 @@ class DBColumn(bc_query_compile.EvalColumn): @@
         entity = meta.get('entity')
         return entity if isinstance(entity, str) else '\0'
     def _return_scalar(self) -> object:
         row = self._db_cursor.fetchone()
         return self._dtype() if row is None else self._dtype(row[0])
     def _return_set(self) -> object:
         return self._dtype(value for value, in self._db_cursor)
     def __call__(self, context: PostingContext) -> object:
         entity = self._entity(ContextMeta(context))
         self._db_cursor.execute(self._db_query, (entity,))
         if issubclass(self._dtype, set):
             return self._dtype(value for value, in self._db_cursor)
         else:
             row = self._db_cursor.fetchone()
             return self._dtype() if row is None else self._dtype(row[0])
         return self._return()
 class DBEmail(DBColumn):

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