Use public api keyword in declaring Cython classes

Use api keyword in declaring API functions.

Use of API defines initializer functions which allows native extensions
that work with dpctl Python types to not link to Python-produced shared
objects on Linux, and allows for pybind11 to portably work with Python
types defined in dpctl.

Example for working with dpctl types is to be added to dpctl/examples

Author: oleksandr-pavlyk

MANIFEST.in

@@ -2,9 +2,15 @@ include versioneer.py
 recursive-include dpctl/include *.h
 recursive-include dpctl *.pxd
 include dpctl/_sycl_context.h
+include dpctl/_sycl_context_api.h
 include dpctl/_sycl_device.h
+include dpctl/_sycl_device_api.h
 include dpctl/_sycl_queue.h
-include dpctl/_sycl_queue_manager.h
+include dpctl/_sycl_queue_api.h
 include dpctl/_sycl_event.h
+include dpctl/_sycl_event_api.h
 include dpctl/memory/_memory.h
+include dpctl/memory/_memory_api.h
+include dpctl/tensor/_usmarray.h
+include dpctl/tensor/_usmarray_api.h
 include dpctl/tests/input_files/*

dpctl/_sycl_context.pxd

@@ -26,7 +26,7 @@ from ._backend cimport DPCTLSyclContextRef
 from ._sycl_device cimport SyclDevice
 
 
-cdef public class _SyclContext [
+cdef public api class _SyclContext [
     object Py_SyclContextObject,
     type Py_SyclContextType
 ]:
@@ -35,7 +35,7 @@ cdef public class _SyclContext [
     cdef DPCTLSyclContextRef _ctxt_ref
 
 
-cdef public class SyclContext(_SyclContext) [
+cdef public api class SyclContext(_SyclContext) [
     object PySyclContextObject,
     type PySyclContextType
 ]:

dpctl/_sycl_context.pyx

@@ -474,7 +474,7 @@ cdef class SyclContext(_SyclContext):
             &_context_capsule_deleter
         )
 
-cdef public DPCTLSyclContextRef get_context_ref(SyclContext ctx):
+cdef api DPCTLSyclContextRef get_context_ref(SyclContext ctx):
     """
     C-API function to get opaque context reference from
     :class:`dpctl.SyclContext` instance.

dpctl/_sycl_device.pxd

@@ -29,7 +29,7 @@ from ._backend cimport (
 )
 
 
-cdef public class _SyclDevice [
+cdef public api class _SyclDevice [
     object Py_SyclDeviceObject,
     type Py_SyclDeviceType
 ]:
@@ -42,7 +42,7 @@ cdef public class _SyclDevice [
     cdef size_t *_max_work_item_sizes
 
 
-cdef public class SyclDevice(_SyclDevice) [
+cdef public api class SyclDevice(_SyclDevice) [
     object PySyclDeviceObject,
     type PySyclDeviceType
 ]:

dpctl/_sycl_device.pyx

@@ -1118,7 +1118,7 @@ cdef class SyclDevice(_SyclDevice):
                 else:
                     return str(relId)
 
-cdef public DPCTLSyclDeviceRef get_device_ref(SyclDevice dev):
+cdef api DPCTLSyclDeviceRef get_device_ref(SyclDevice dev):
     """
     C-API function to get opaque device reference from
     :class:`dpctl.SyclDevice` instance.

dpctl/_sycl_event.pxd

@@ -23,7 +23,7 @@
 from ._backend cimport DPCTLSyclEventRef
 
 
-cdef public class SyclEvent [object PySyclEventObject, type PySyclEventType]:
+cdef public api class SyclEvent [object PySyclEventObject, type PySyclEventType]:
     ''' Wrapper class for a Sycl Event
     '''
     cdef  DPCTLSyclEventRef _event_ref

dpctl/_sycl_event.pyx

@@ -32,6 +32,13 @@ __all__ = [
 _logger = logging.getLogger(__name__)
 
 
+cdef api DPCTLSyclEventRef get_event_ref(SyclEvent ev):
+    """ C-API function to access opaque event reference from
+    Python object of type :class:`dpctl.SyclEvent`.
+    """
+    return ev.get_event_ref()
+
+
 cdef class SyclEvent:
     """ Python wrapper class for cl::sycl::event.
     """

dpctl/_sycl_queue.pxd

@@ -31,7 +31,7 @@ from .program._program cimport SyclKernel
 
 cdef void default_async_error_handler(int) nogil except *
 
-cdef public class _SyclQueue [
+cdef public api class _SyclQueue [
     object Py_SyclQueueObject, type Py_SyclQueueType
 ]:
     """ Python data owner class for a sycl::queue.
@@ -41,7 +41,7 @@ cdef public class _SyclQueue [
     cdef SyclDevice _device
 
 
-cdef public class SyclQueue (_SyclQueue) [
+cdef public api class SyclQueue (_SyclQueue) [
     object PySyclQueueObject, type PySyclQueueType
 ]:
     """ Python wrapper class for a sycl::queue.

dpctl/_sycl_queue.pyx

@@ -969,7 +969,7 @@ cdef class SyclQueue(_SyclQueue):
         self.sycl_device.print_device_info()
 
 
-cdef public DPCTLSyclQueueRef get_queue_ref(SyclQueue q):
+cdef api DPCTLSyclQueueRef get_queue_ref(SyclQueue q):
     """
     C-API function to get opaque queue reference from
     :class:`dpctl.SyclQueue` instance.

dpctl/memory/_memory.pxd

@@ -32,7 +32,7 @@ cdef DPCTLSyclQueueRef get_queue_ref_from_ptr_and_syclobj(
     DPCTLSyclUSMRef ptr, object syclobj)
 
 
-cdef public class _Memory [object Py_MemoryObject, type Py_MemoryType]:
+cdef public api class _Memory [object Py_MemoryObject, type Py_MemoryType]:
     cdef DPCTLSyclUSMRef memory_ptr
     cdef Py_ssize_t nbytes
     cdef SyclQueue queue
@@ -51,25 +51,25 @@ cdef public class _Memory [object Py_MemoryObject, type Py_MemoryType]:
     cpdef bytes tobytes(self)
 
     @staticmethod
-    cdef public SyclDevice get_pointer_device(
+    cdef SyclDevice get_pointer_device(
         DPCTLSyclUSMRef p, SyclContext ctx)
     @staticmethod
-    cdef public bytes get_pointer_type(DPCTLSyclUSMRef p, SyclContext ctx)
+    cdef bytes get_pointer_type(DPCTLSyclUSMRef p, SyclContext ctx)
     @staticmethod
-    cdef public object create_from_usm_pointer_size_qref(
+    cdef object create_from_usm_pointer_size_qref(
         DPCTLSyclUSMRef USMRef,
         Py_ssize_t nbytes,
         DPCTLSyclQueueRef QRef,
         object memory_owner=*
     )
 
 
-cdef public class MemoryUSMShared(_Memory) [object PyMemoryUSMSharedObject,
+cdef public api class MemoryUSMShared(_Memory) [object PyMemoryUSMSharedObject,
                                             type PyMemoryUSMSharedType]:
     pass
 
 
-cdef public class MemoryUSMHost(_Memory) [object PyMemoryUSMHostObject,
+cdef public api class MemoryUSMHost(_Memory) [object PyMemoryUSMHostObject,
                                           type PyMemoryUSMHostType]:
     pass
 

dpctl/memory/_memory.pyx

@@ -708,11 +708,11 @@ def as_usm_memory(obj):
         )
 
 
-cdef public DPCTLSyclUSMRef get_usm_pointer(_Memory obj):
+cdef api DPCTLSyclUSMRef get_usm_pointer(_Memory obj):
     return obj.memory_ptr
 
-cdef public DPCTLSyclContextRef get_context(_Memory obj):
+cdef api DPCTLSyclContextRef get_context(_Memory obj):
     return obj.queue._context.get_context_ref()
 
-cdef public size_t get_nbytes(_Memory obj):
+cdef api size_t get_nbytes(_Memory obj):
     return <size_t>obj.nbytes

dpctl/tensor/_usmarray.pxd

@@ -9,7 +9,7 @@ cdef public int USM_ARRAY_F_CONTIGUOUS
 cdef public int USM_ARRAY_WRITEABLE
 
 
-cdef public class usm_ndarray [object PyUSMArrayObject, type PyUSMArrayType]:
+cdef public api class usm_ndarray [object PyUSMArrayObject, type PyUSMArrayType]:
     # data fields
     cdef char* data_
     cdef readonly int nd_