Files
deb-python-cassandra-driver/cassandra/objparser.pyx

60 lines
1.9 KiB
Cython

include "ioutils.pyx"
from cassandra.bytesio cimport BytesIOReader
from cassandra.deserializers cimport Deserializer, from_binary
from cassandra.parsing cimport ParseDesc, ColumnParser, RowParser
from cassandra.tuple cimport tuple_new, tuple_set
cdef class ListParser(ColumnParser):
"""Decode a ResultMessage into a list of tuples (or other objects)"""
cpdef parse_rows(self, BytesIOReader reader, ParseDesc desc):
cdef Py_ssize_t i, rowcount
rowcount = read_int(reader)
cdef RowParser rowparser = TupleRowParser()
return [rowparser.unpack_row(reader, desc) for i in range(rowcount)]
cdef class LazyParser(ColumnParser):
"""Decode a ResultMessage lazily using a generator"""
cpdef parse_rows(self, BytesIOReader reader, ParseDesc desc):
# Use a little helper function as closures (generators) are not
# supported in cpdef methods
return parse_rows_lazy(reader, desc)
def parse_rows_lazy(BytesIOReader reader, ParseDesc desc):
cdef Py_ssize_t i, rowcount
rowcount = read_int(reader)
cdef RowParser rowparser = TupleRowParser()
return (rowparser.unpack_row(reader, desc) for i in range(rowcount))
cdef class TupleRowParser(RowParser):
"""
Parse a single returned row into a tuple of objects:
(obj1, ..., objN)
"""
cpdef unpack_row(self, BytesIOReader reader, ParseDesc desc):
cdef Buffer buf
cdef Py_ssize_t i, rowsize = desc.rowsize
cdef Deserializer deserializer
cdef tuple res = tuple_new(desc.rowsize)
for i in range(rowsize):
# Read the next few bytes
get_buf(reader, &buf)
# Deserialize bytes to python object
deserializer = desc.deserializers[i]
val = from_binary(deserializer, &buf, desc.protocol_version)
# Insert new object into tuple
tuple_set(res, i, val)
return res