Migrate copy_column and Column.from_scalar to pylibcudf (#17513)

Apart of #15162

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

Approvers:
  - Vyas Ramasubramani (https://github.com/vyasr)

URL: #17513

python/cudf/cudf/_lib/column.pyx

@@ -42,8 +42,7 @@ cimport pylibcudf.libcudf.types as libcudf_types
 cimport pylibcudf.libcudf.unary as libcudf_unary
 from pylibcudf.libcudf.column.column cimport column, column_contents
 from pylibcudf.libcudf.column.column_factories cimport (
-    make_column_from_scalar as cpp_make_column_from_scalar,
-    make_numeric_column,
+    make_numeric_column
 )
 from pylibcudf.libcudf.column.column_view cimport column_view
 from pylibcudf.libcudf.null_mask cimport null_count as cpp_null_count
@@ -840,9 +839,8 @@ cdef class Column:
 
     @staticmethod
     def from_scalar(py_val, size_type size):
-        cdef DeviceScalar val = py_val.device_value
-        cdef const scalar* c_val = val.get_raw_ptr()
-        cdef unique_ptr[column] c_result
-        with nogil:
-            c_result = move(cpp_make_column_from_scalar(c_val[0], size))
-        return Column.from_unique_ptr(move(c_result))
+        return Column.from_pylibcudf(
+            pylibcudf.Column.from_scalar(
+                py_val.device_value.c_value, size
+            )
+        )

python/cudf/cudf/_lib/copying.pyx

@@ -3,8 +3,6 @@
 import pickle
 
 from libcpp cimport bool
-from libcpp.memory cimport unique_ptr
-from libcpp.utility cimport move
 import pylibcudf
 
 import cudf
@@ -18,10 +16,6 @@ from cudf._lib.scalar cimport DeviceScalar
 
 from cudf._lib.reduce import minmax
 
-from libcpp.memory cimport make_unique
-
-from pylibcudf.libcudf.column.column cimport column
-from pylibcudf.libcudf.column.column_view cimport column_view
 from pylibcudf.libcudf.types cimport size_type
 
 from cudf._lib.utils cimport columns_from_pylibcudf_table, data_from_pylibcudf_table
@@ -59,12 +53,9 @@ def copy_column(Column input_column):
     -------
     Deep copied column
     """
-    cdef unique_ptr[column] c_result
-    cdef column_view input_column_view = input_column.view()
-    with nogil:
-        c_result = move(make_unique[column](input_column_view))
-
-    return Column.from_unique_ptr(move(c_result))
+    return Column.from_pylibcudf(
+        input_column.to_pylibcudf(mode="read").copy()
+    )
 
 
 @acquire_spill_lock()