Modularize stream validation into a function.

Stream keyword validation and deployment was copy-pasted in several
places. Created function _stream_validate_and_use, and used it in
a couple of places.

This brings uniformity of error messages, and should improve coverage
and maintainability.

dpctl/tensor/_usmarray.pyx

@@ -149,6 +149,19 @@ cdef bint _is_host_cpu(object dl_device):
     return (dl_type == DLDeviceType.kDLCPU) and (dl_id == 0)
 
 
+cdef void _validate_and_use_stream(object stream, c_dpctl.SyclQueue self_queue) except *:
+    if (stream is None or stream == self_queue):
+        pass
+    else:
+        if not isinstance(stream, dpctl.SyclQueue):
+            raise TypeError(
+                "stream argument type was expected to be dpctl.SyclQueue,"
+                f" got {type(stream)} instead"
+            )
+        ev = self_queue.submit_barrier()
+        stream.submit_barrier(dependent_events=[ev])
+
+
 cdef class usm_ndarray:
     """ usm_ndarray(shape, dtype=None, strides=None, buffer="device", \
            offset=0, order="C", buffer_ctor_kwargs=dict(), \
@@ -1025,16 +1038,7 @@ cdef class usm_ndarray:
         cdef c_dpmem._Memory arr_buf
         d = Device.create_device(target_device)
 
-        if (stream is None or stream == self.sycl_queue):
-            pass
-        else:
-            if not isinstance(stream, dpctl.SyclQueue):
-                raise TypeError(
-                    "stream argument type was expected to be dpctl.SyclQueue,"
-                    f" got {type(stream)} instead"
-                )
-            ev = self.sycl_queue.submit_barrier()
-            stream.submit_barrier(dependent_events=[ev])
+        _validate_and_use_stream(stream, self.sycl_queue)
 
         if (d.sycl_context == self.sycl_context):
             arr_buf = <c_dpmem._Memory> self.usm_data
@@ -1207,17 +1211,7 @@ cdef class usm_ndarray:
             # legacy path for DLManagedTensor
             # copy kwarg ignored because copy flag can't be set
             _caps = c_dlpack.to_dlpack_capsule(self)
-            if (stream is None or stream == self.sycl_queue):
-                pass
-            else:
-                if not isinstance(stream, dpctl.SyclQueue):
-                    raise TypeError(
-                        "stream keyword argument type is expected to "
-                        "be dpctl.SyclQueue, "
-                        f" got {type(stream)} instead"
-                    )
-                ev = self.sycl_queue.submit_barrier()
-                stream.submit_barrier(dependent_events=[ev])
+            _validate_and_use_stream(stream, self.sycl_queue)
             return _caps
         else:
             if not isinstance(max_version, tuple) or len(max_version) != 2:
@@ -1259,12 +1253,7 @@ cdef class usm_ndarray:
                     copy = False
                 # TODO: strategy for handling stream on different device from dl_device
                 if copy:
-                    if (stream is None or type(stream) is not dpctl.SyclQueue or
-                        stream == self.sycl_queue):
-                        pass
-                    else:
-                        ev = self.sycl_queue.submit_barrier()
-                        stream.submit_barrier(dependent_events=[ev])
+                    _validate_and_use_stream(stream, self.sycl_queue)
                     nbytes = self.usm_data.nbytes
                     copy_buffer = type(self.usm_data)(
                         nbytes, queue=self.sycl_queue
@@ -1281,22 +1270,12 @@ cdef class usm_ndarray:
                     _caps = c_dlpack.to_dlpack_versioned_capsule(_copied_arr, copy)
                 else:
                     _caps = c_dlpack.to_dlpack_versioned_capsule(self, copy)
-                    if (stream is None or type(stream) is not dpctl.SyclQueue or
-                        stream == self.sycl_queue):
-                        pass
-                    else:
-                        ev = self.sycl_queue.submit_barrier()
-                        stream.submit_barrier(dependent_events=[ev])
+                    _validate_and_use_stream(stream, self.sycl_queue)
                 return _caps
             else:
                 # legacy path for DLManagedTensor
                 _caps = c_dlpack.to_dlpack_capsule(self)
-                if (stream is None or type(stream) is not dpctl.SyclQueue or
-                    stream == self.sycl_queue):
-                    pass
-                else:
-                    ev = self.sycl_queue.submit_barrier()
-                    stream.submit_barrier(dependent_events=[ev])
+                _validate_and_use_stream(stream, self.sycl_queue)
                 return _caps
 
     def __dlpack_device__(self):