1.1rc4: delete

ptvp35/__init__.py

@@ -60,13 +60,21 @@ class LineRequest(Request):
         self.line = line
 
 
-class KVFactory(abc.ABC):
+class KVProtocol(abc.ABC):
+    @abc.abstractmethod
+    def dbget(self, db: dict, key: Any, default: Any, /):
+        raise NotImplementedError
+
+
+class KVFactory(KVProtocol):
     """this class is for working with already normalised data values, not for data transformation (e.g. reducing keys to a common form).
 that functionality may be added in the future, though, probably, only for custom DbConnection implementations.
 note: unstable signature."""
 
     __slots__ = ()
 
+    DELETE = object()
+
     @abc.abstractmethod
     def line(self, key: Any, value: Any, /) -> str:
         """line must contain exactly one '\\n' at exactly the end if the line is not empty.
@@ -79,12 +87,31 @@ note: other forms of requests will later be represented by different methods or
 note: unstable signature."""
         raise NotImplementedError
 
-    def run(self, line: str, db: dict, /) -> None:
+    def run(self, line: str, db: dict, reduce: bool, /) -> None:
         """run request against the db.
 extensible to allow forms of requests other than set.
 note: unstable signature."""
         key, value = self.fromline(line)
-        db[key] = value
+        self._dbset(db, key, value, reduce)
+
+    def _dbset(self, db: dict, key: Any, value: Any, reduce: bool, /):
+        if reduce and value is self.DELETE:
+            db.pop(key, None)
+        else:
+            db[key] = value
+
+    def dbset(self, db: dict, key: Any, value: Any, /):
+        self._dbset(db, key, value, True)
+
+    def dbget(self, db: dict, key: Any, default: Any, /):
+        value = db.get(key, default)
+        return self.filter_value(value, default)
+
+    def filter_value(self, value: Any, default: Any, /):
+        if value is self.DELETE:
+            return default
+        else:
+            return value
 
     def request(self, key: Any, value: Any, /, *, future: asyncio.Future | None) -> 'KVRequest':
         """form request with Future.
@@ -97,11 +124,11 @@ note: unstable signature."""
 note: unstable signature."""
         return self.request(key, value, future=None)
 
-    def io2db(self, io: IO[str], db: dict, /) -> int:
+    def io2db(self, io: IO[str], db: dict, reduce: bool, /) -> int:
         """note: unstable signature."""
         size = 0
         for line in io:
-            self.run(line, db)
+            self.run(line, db, reduce)
             size += len(line)
         return size
 
@@ -141,7 +168,11 @@ class KVJson(KVFactory):
     __slots__ = ()
 
     def line(self, key: Any, value: Any, /) -> str:
-        return json.dumps({'key': key, 'value': value}) + '\n'
+        if value is self.DELETE:
+            obj = {'key': key}
+        else:
+            obj = {'key': key, 'value': value}
+        return json.dumps(obj) + '\n'
 
     def _load_key(self, key: Any, /) -> Hashable:
         """note: unstable signature."""
@@ -157,7 +188,7 @@ class KVJson(KVFactory):
 
     def fromline(self, line: str, /) -> tuple[Any, Any]:
         d = json.loads(line)
-        return self._load_key(d['key']), d['value']
+        return self._load_key(d['key']), d.get('value', self.DELETE)
 
 
 class TransactionRequest(LineRequest):
@@ -249,6 +280,10 @@ class VirtualConnection(abc.ABC):
     def get(self, key: Any, default: Any, /):
         raise NotImplementedError
 
+    @abc.abstractmethod
+    def kvprotocol(self, /) -> KVProtocol:
+        raise NotImplementedError
+
     @abc.abstractmethod
     async def commit_transaction(self, delta: dict, /) -> None:
         raise NotImplementedError
@@ -337,7 +372,7 @@ class DbConnection(VirtualConnection):
     def _path2db_sync(self, path: pathlib.Path, db: dict, /) -> int:
         path.touch()
         with path.open('r') as file:
-            return self.__kvfactory.io2db(file, db)
+            return self.__kvfactory.io2db(file, db, True)
 
     def _db2path_sync(self, db: dict, path: pathlib.Path, /) -> int:
         with path.open('w') as file:
@@ -345,22 +380,26 @@ class DbConnection(VirtualConnection):
             os.fsync(file.fileno())
             return initial_size
 
+    def kvprotocol(self, /) -> KVProtocol:
+        return self.__kvfactory
+
     def get(self, key: Any, default: Any, /):
         """dict-like get with mandatory default parametre."""
-        return self.__mmdb.get(key, default)
+        return self.__kvfactory.dbget(self.__mmdb, key, default)
 
     async def set(self, key: Any, value: Any, /) -> None:
         """set the value and wait until it's written to disk."""
         future = self._create_future()
         request = self.__kvfactory.request(key, value, future=future)
-        self.__mmdb[key] = value
+        self.__kvfactory.dbset(self.__mmdb, key, value)
         self.__queue.put_nowait(request)
         await future
 
     def set_nowait(self, key: Any, value: Any, /) -> None:
         """set value and add write-to-disk request to queue."""
-        self.__mmdb[key] = value
+        request = self.__kvfactory.free(key, value)
-        self.__queue.put_nowait(self.__kvfactory.free(key, value))
+        self.__kvfactory.dbset(self.__mmdb, key, value)
+        self.__queue.put_nowait(request)
 
     def _clear_buffer(self, /) -> None:
         self.__buffer = StringIO()
@@ -370,7 +409,7 @@ class DbConnection(VirtualConnection):
     def _compress_buffer(self, /) -> StringIO:
         self.__buffer.seek(0)
         bufferdb = {}
-        self.__kvfactory.io2db(self.__buffer, bufferdb)
+        self.__kvfactory.io2db(self.__buffer, bufferdb, False)
         buffer = StringIO()
         self.__kvfactory.db2io(bufferdb, buffer)
         return buffer
@@ -609,7 +648,7 @@ intended for heavy tasks."""
     async def create(cls, parametres: DbParametres, /) -> 'DbConnection':
         """connect to the factory.
 note: unstable signature."""
-        dbconnection = cls(parametres)
+        dbconnection = DbConnection(parametres)
         await dbconnection._initialize()
         return dbconnection
 
@@ -656,7 +695,8 @@ note: unstable signature."""
     def _transaction_buffer(self, delta: dict, /) -> StringIO:
         buffer = StringIO()
         self.__kvfactory.db2io(delta, buffer)
-        self.__mmdb.update(delta)
+        for key, value in delta.items():
+            self.__kvfactory.dbset(self.__mmdb, key, value)
         return buffer
 
     async def commit_transaction(self, delta: dict, /) -> None:
@@ -764,6 +804,7 @@ class TransactionView(VirtualConnection):
         '__shadow',
         '__connection',
         '__loop',
+        '__kvprotocol',
         '__subfuture',
     )
 
@@ -772,6 +813,7 @@ class TransactionView(VirtualConnection):
         self.__shadow = {}
         self.__connection = connection
         self.__loop = connection.loop()
+        self.__kvprotocol = connection.kvprotocol()
         self.__subfuture: asyncio.Future | None = None
 
     def future_context(self, /) -> FutureContext:
@@ -829,13 +871,17 @@ class TransactionView(VirtualConnection):
         async with self.future_context():
             self.reset()
 
+    def kvprotocol(self, /) -> KVProtocol:
+        return self.__kvprotocol
+
     def get(self, key: Any, default: Any, /):
         """get from the delta (unsubmitted), else from the shadow (submitted), else from the connection."""
         if key in self.__delta:
-            return self.__delta[key]
+            return self.__kvprotocol.dbget(self.__delta, key, default)
-        if key in self.__shadow:
+        elif key in self.__shadow:
-            return self.__shadow[key]
+            return self.__kvprotocol.dbget(self.__shadow, key, default)
-        return self.__connection.get(key, default)
+        else:
+            return self.__connection.get(key, default)
 
     def set_nowait(self, key: Any, value: Any, /) -> None:
         """note: unlike the corresponding db method, this one does not catch serialisation errors early."""

setup.py

@@ -2,7 +2,7 @@ from setuptools import setup
 
 setup(
     name='ptvp35',
-    version='1.1rc3',
+    version='1.1rc4',
     packages=['ptvp35'],
     url='https://gitea.ongoteam.net/PTV/ptvp35',
     license='MIT',

test_delete.py

@@ -0,0 +1,22 @@
+import asyncio
+import pathlib
+
+from ptvp35 import *
+
+
+async def main():
+    path = pathlib.Path('test_delete.db')
+    path.unlink(missing_ok=True)
+    async with DbFactory(path, kvfactory=KVJson()) as connection:
+        connection.set_nowait(0, 0)
+        print(connection.get(0, 1))
+        await connection.commit()
+        async with connection.transaction() as transaction:
+            print(transaction.get(0, 1))
+            transaction.set_nowait(0, KVFactory.DELETE)
+            print(transaction.get(0, 1))
+        input()
+        print(connection.get(0, 1))
+    # path.unlink(missing_ok=True)
+
+asyncio.run(main())