76 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			Cython
		
	
	
	
	
	
			
		
		
	
	
			76 lines
		
	
	
		
			2.5 KiB
		
	
	
	
		
			Cython
		
	
	
	
	
	
| # Copyright 2013-2016 DataStax, Inc.
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| #
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| # Licensed under the Apache License, Version 2.0 (the "License");
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| # you may not use this file except in compliance with the License.
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| # You may obtain a copy of the License at
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| #
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| # http://www.apache.org/licenses/LICENSE-2.0
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| #
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| # Unless required by applicable law or agreed to in writing, software
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| # distributed under the License is distributed on an "AS IS" BASIS,
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| # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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| # See the License for the specific language governing permissions and
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| # limitations under the License.
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| 
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| include "ioutils.pyx"
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| 
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| from cassandra.bytesio cimport BytesIOReader
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| from cassandra.deserializers cimport Deserializer, from_binary
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| from cassandra.parsing cimport ParseDesc, ColumnParser, RowParser
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| from cassandra.tuple cimport tuple_new, tuple_set
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| 
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| 
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| cdef class ListParser(ColumnParser):
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|     """Decode a ResultMessage into a list of tuples (or other objects)"""
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| 
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|     cpdef parse_rows(self, BytesIOReader reader, ParseDesc desc):
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|         cdef Py_ssize_t i, rowcount
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|         rowcount = read_int(reader)
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|         cdef RowParser rowparser = TupleRowParser()
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|         return [rowparser.unpack_row(reader, desc) for i in range(rowcount)]
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| 
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| 
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| cdef class LazyParser(ColumnParser):
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|     """Decode a ResultMessage lazily using a generator"""
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| 
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|     cpdef parse_rows(self, BytesIOReader reader, ParseDesc desc):
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|         # Use a little helper function as closures (generators) are not
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|         # supported in cpdef methods
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|         return parse_rows_lazy(reader, desc)
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| 
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| 
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| def parse_rows_lazy(BytesIOReader reader, ParseDesc desc):
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|     cdef Py_ssize_t i, rowcount
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|     rowcount = read_int(reader)
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|     cdef RowParser rowparser = TupleRowParser()
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|     return (rowparser.unpack_row(reader, desc) for i in range(rowcount))
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| 
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| 
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| cdef class TupleRowParser(RowParser):
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|     """
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|     Parse a single returned row into a tuple of objects:
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| 
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|         (obj1, ..., objN)
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|     """
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| 
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|     cpdef unpack_row(self, BytesIOReader reader, ParseDesc desc):
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|         assert desc.rowsize >= 0
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| 
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|         cdef Buffer buf
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|         cdef Py_ssize_t i, rowsize = desc.rowsize
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|         cdef Deserializer deserializer
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|         cdef tuple res = tuple_new(desc.rowsize)
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| 
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|         for i in range(rowsize):
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|             # Read the next few bytes
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|             get_buf(reader, &buf)
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| 
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|             # Deserialize bytes to python object
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|             deserializer = desc.deserializers[i]
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|             val = from_binary(deserializer, &buf, desc.protocol_version)
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| 
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|             # Insert new object into tuple
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|             tuple_set(res, i, val)
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| 
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|         return res
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