PYTHON-1352 Add vector type, codec + support for parsing CQL type (datastax#1161)

Author: absurdfarce

cassandra/__init__.py

@@ -23,7 +23,7 @@ def emit(self, record):
 
 logging.getLogger('cassandra').addHandler(NullHandler())
 
-__version_info__ = (3, 27, 0)
+__version_info__ = (3, 28, 0b1)
 __version__ = '.'.join(map(str, __version_info__))
 
 

cassandra/cqltypes.py

@@ -226,13 +226,15 @@ def parse_casstype_args(typestring):
             else:
                 names.append(None)
 
-            ctype = lookup_casstype_simple(tok)
+            try:
+                ctype = int(tok)
+            except ValueError:
+                ctype = lookup_casstype_simple(tok)
             types.append(ctype)
 
     # return the first (outer) type, which will have all parameters applied
     return args[0][0][0]
 
-
 def lookup_casstype(casstype):
     """
     Given a Cassandra type as a string (possibly including parameters), hand
@@ -250,6 +252,7 @@ def lookup_casstype(casstype):
     try:
         return parse_casstype_args(casstype)
     except (ValueError, AssertionError, IndexError) as e:
+        log.debug("Exception in parse_casstype_args: %s" % e)
         raise ValueError("Don't know how to parse type string %r: %s" % (casstype, e))
 
 
@@ -286,7 +289,7 @@ class _CassandraType(object, metaclass=CassandraTypeType):
     """
 
     def __repr__(self):
-        return '<%s( %r )>' % (self.cql_parameterized_type(), self.val)
+        return '<%s>' % (self.cql_parameterized_type())
 
     @classmethod
     def from_binary(cls, byts, protocol_version):
@@ -1402,3 +1405,31 @@ def serialize(cls, v, protocol_version):
             buf.write(int8_pack(cls._encode_precision(bound.precision)))
 
         return buf.getvalue()
+
+class VectorType(_CassandraType):
+    typename = 'org.apache.cassandra.db.marshal.VectorType'
+    vector_size = 0
+    subtype = None
+
+    @classmethod
+    def apply_parameters(cls, params, names):
+        assert len(params) == 2
+        subtype = lookup_casstype(params[0])
+        vsize = params[1]
+        return type('%s(%s)' % (cls.cass_parameterized_type_with([]), vsize), (cls,), {'vector_size': vsize, 'subtype': subtype})
+
+    @classmethod
+    def deserialize(cls, byts, protocol_version):
+        indexes = (4 * x for x in range(0, cls.vector_size))
+        return [cls.subtype.deserialize(byts[idx:idx + 4], protocol_version) for idx in indexes]
+
+    @classmethod
+    def serialize(cls, v, protocol_version):
+        buf = io.BytesIO()
+        for item in v:
+            buf.write(cls.subtype.serialize(item, protocol_version))
+        return buf.getvalue()
+
+    @classmethod
+    def cql_parameterized_type(cls):
+        return "%s<%s, %s>" % (cls.typename, cls.subtype.typename, cls.vector_size)

tests/unit/test_types.py

@@ -25,7 +25,8 @@
     EmptyValue, LongType, SetType, UTF8Type,
     cql_typename, int8_pack, int64_pack, lookup_casstype,
     lookup_casstype_simple, parse_casstype_args,
-    int32_pack, Int32Type, ListType, MapType
+    int32_pack, Int32Type, ListType, MapType, VectorType,
+    FloatType
 )
 from cassandra.encoder import cql_quote
 from cassandra.pool import Host
@@ -188,6 +189,12 @@ class BarType(FooType):
         self.assertEqual(UTF8Type, ctype.subtypes[2])
         self.assertEqual([b'city', None, b'zip'], ctype.names)
 
+    def test_parse_casstype_vector(self):
+        ctype = parse_casstype_args("org.apache.cassandra.db.marshal.VectorType(org.apache.cassandra.db.marshal.FloatType, 3)")
+        self.assertTrue(issubclass(ctype, VectorType))
+        self.assertEqual(3, ctype.vector_size)
+        self.assertEqual(FloatType, ctype.subtype)
+
     def test_empty_value(self):
         self.assertEqual(str(EmptyValue()), 'EMPTY')
 
@@ -301,6 +308,19 @@ def test_cql_quote(self):
         self.assertEqual(cql_quote('test'), "'test'")
         self.assertEqual(cql_quote(0), '0')
 
+    def test_vector_round_trip(self):
+        base = [3.4, 2.9, 41.6, 12.0]
+        ctype = parse_casstype_args("org.apache.cassandra.db.marshal.VectorType(org.apache.cassandra.db.marshal.FloatType, 4)")
+        base_bytes = ctype.serialize(base, 0)
+        self.assertEqual(16, len(base_bytes))
+        result = ctype.deserialize(base_bytes, 0)
+        self.assertEqual(len(base), len(result))
+        for idx in range(0,len(base)):
+            self.assertAlmostEqual(base[idx], result[idx], places=5)
+
+    def test_vector_cql_parameterized_type(self):
+        ctype = parse_casstype_args("org.apache.cassandra.db.marshal.VectorType(org.apache.cassandra.db.marshal.FloatType, 4)")
+        self.assertEqual(ctype.cql_parameterized_type(), "org.apache.cassandra.db.marshal.VectorType<float, 4>")
 
 ZERO = datetime.timedelta(0)