GPU Python: Use 'PyC_ParseStringEnum' to parse items

Currently the GPU module for python has different ways to handle enums.
- Organizing items in `PyC_StringEnumItems` arrays and parsing them with `PyC_ParseStringEnum`.
- Using dedicated functions for each type of enum (`bpygpu_ParsePrimType`, `pygpu_ParseVertCompType` and `pygpu_ParseVertFetchMode`).

Although apparently more efficient (especially `pygpu_ParseVertCompType`
which transforms strings into integers for simple comparison), these
dedicated functions duplicate functionality, increase the complexity of
the code and consequently make it less readable.

Reviewed By: campbellbarton

Differential Revision: https://developer.blender.org/D10456

source/blender/python/gpu/gpu_py_api.c

@@ -31,7 +31,6 @@
 #include "../generic/python_utildefines.h"
 
 #include "GPU_init_exit.h"
-#include "GPU_primitive.h"
 
 #include "gpu_py_matrix.h"
 #include "gpu_py_select.h"
@@ -58,50 +57,6 @@ bool bpygpu_is_init_or_error(void)
 
 /** \} */
 
-/* -------------------------------------------------------------------- */
-/** \name Primitive Type Utils
- * \{ */
-
-int bpygpu_ParsePrimType(PyObject *o, void *p)
-{
-  Py_ssize_t mode_id_len;
-  const char *mode_id = PyUnicode_AsUTF8AndSize(o, &mode_id_len);
-  if (mode_id == NULL) {
-    PyErr_Format(PyExc_ValueError, "expected a string, got %s", Py_TYPE(o)->tp_name);
-    return 0;
-  }
-#define MATCH_ID(id) \
-  if (mode_id_len == strlen(STRINGIFY(id))) { \
-    if (STREQ(mode_id, STRINGIFY(id))) { \
-      mode = GPU_PRIM_##id; \
-      goto success; \
-    } \
-  } \
-  ((void)0)
-
-  GPUPrimType mode;
-  MATCH_ID(POINTS);
-  MATCH_ID(LINES);
-  MATCH_ID(TRIS);
-  MATCH_ID(LINE_STRIP);
-  MATCH_ID(LINE_LOOP);
-  MATCH_ID(TRI_STRIP);
-  MATCH_ID(TRI_FAN);
-  MATCH_ID(LINES_ADJ);
-  MATCH_ID(TRIS_ADJ);
-  MATCH_ID(LINE_STRIP_ADJ);
-
-#undef MATCH_ID
-  PyErr_Format(PyExc_ValueError, "unknown type literal: '%s'", mode_id);
-  return 0;
-
-success:
-  (*(GPUPrimType *)p) = mode;
-  return 1;
-}
-
-/** \} */
-
 /* -------------------------------------------------------------------- */
 /** \name GPU Module
  * \{ */