Remove unused BufferArrayFromVector (#17549)

Follow up to #17506. This PR removes an unused buffer class.

Authors:
  - Matthew Murray (https://github.com/Matt711)

Approvers:
  - Matthew Roeschke (https://github.com/mroeschke)

URL: #17549

python/cudf/cudf/_lib/parquet.pyx

@@ -20,11 +20,8 @@ from cudf._lib.utils cimport _data_from_columns, data_from_pylibcudf_io
 
 from cudf._lib.utils import _index_level_name, generate_pandas_metadata
 
-from libc.stdint cimport int64_t, uint8_t
+from libc.stdint cimport int64_t
 from libcpp cimport bool
-from libcpp.memory cimport unique_ptr
-from libcpp.utility cimport move
-from libcpp.vector cimport vector
 
 from pylibcudf.expressions cimport Expression
 from pylibcudf.io.parquet cimport ChunkedParquetReader
@@ -47,47 +44,6 @@ from pylibcudf cimport Table
 from cudf.utils.ioutils import _ROW_GROUP_SIZE_BYTES_DEFAULT
 from pylibcudf.io.types cimport TableInputMetadata, SinkInfo, ColumnInMetadata
 from pylibcudf.io.parquet cimport ParquetChunkedWriter
-from cython.operator cimport dereference
-
-
-cdef class BufferArrayFromVector:
-    cdef Py_ssize_t length
-    cdef unique_ptr[vector[uint8_t]] in_vec
-
-    # these two things declare part of the buffer interface
-    cdef Py_ssize_t shape[1]
-    cdef Py_ssize_t strides[1]
-
-    @staticmethod
-    cdef BufferArrayFromVector from_unique_ptr(
-        unique_ptr[vector[uint8_t]] in_vec
-    ):
-        cdef BufferArrayFromVector buf = BufferArrayFromVector()
-        buf.in_vec = move(in_vec)
-        buf.length = dereference(buf.in_vec).size()
-        return buf
-
-    def __getbuffer__(self, Py_buffer *buffer, int flags):
-        cdef Py_ssize_t itemsize = sizeof(uint8_t)
-
-        self.shape[0] = self.length
-        self.strides[0] = 1
-
-        buffer.buf = dereference(self.in_vec).data()
-
-        buffer.format = NULL  # byte
-        buffer.internal = NULL
-        buffer.itemsize = itemsize
-        buffer.len = self.length * itemsize   # product(shape) * itemsize
-        buffer.ndim = 1
-        buffer.obj = self
-        buffer.readonly = 0
-        buffer.shape = self.shape
-        buffer.strides = self.strides
-        buffer.suboffsets = NULL
-
-    def __releasebuffer__(self, Py_buffer *buffer):
-        pass
 
 
 def _parse_metadata(meta):