Refactor save_picklebuffer to use PyObject_GetBuffer on PickleBuffer directly

Author: Aaron Wieczorek

Modules/_pickle.c

@@ -2636,23 +2636,18 @@ save_picklebuffer(PickleState *st, PicklerObject *self, PyObject *obj)
                         "PickleBuffer can only be pickled with protocol >= 5");
         return -1;
     }
-    const Py_buffer* view = PyPickleBuffer_GetBuffer(obj);
-    if (view == NULL) {
+    Py_buffer view;
+    if (PyObject_GetBuffer(obj, &view, PyBUF_FULL_RO) != 0) {
         return -1;
     }
-    if (view->suboffsets != NULL || !PyBuffer_IsContiguous(view, 'A')) {
+    if (view.suboffsets != NULL || !PyBuffer_IsContiguous(&view, 'A')) {
         PyErr_SetString(st->PicklingError,
                         "PickleBuffer can not be pickled when "
                         "pointing to a non-contiguous buffer");
-        return -1;
+        goto error;
     }
 
     int rc = 0;
-    Py_buffer keepalive_view; // to ensure that 'view' is kept alive
-    if (PyObject_GetBuffer(view->obj, &keepalive_view, PyBUF_FULL_RO) != 0) {
-        return -1;
-    }
-
     int in_band = 1;
     if (self->buffer_callback != NULL) {
         PyObject *ret = PyObject_CallOneArg(self->buffer_callback, obj);
@@ -2667,36 +2662,34 @@ save_picklebuffer(PickleState *st, PicklerObject *self, PyObject *obj)
     }
     if (in_band) {
         /* Write data in-band */
-        if (view->readonly) {
-            rc = _save_bytes_data(st, self, obj, (const char *)view->buf,
-                                    view->len);
+        if (view.readonly) {
+            rc = _save_bytes_data(st, self, obj, (const char *)view.buf,
+                                    view.len);
         }
         else {
-            rc = _save_bytearray_data(st, self, obj, (const char *)view->buf,
-                                        view->len);
+            rc = _save_bytearray_data(st, self, obj, (const char *)view.buf,
+                                        view.len);
         }
-        goto exit;
     }
     else {
         /* Write data out-of-band */
         const char next_buffer_op = NEXT_BUFFER;
         if (_Pickler_Write(self, &next_buffer_op, 1) < 0) {
             goto error;
         }
-        if (view->readonly) {
+        if (view.readonly) {
             const char readonly_buffer_op = READONLY_BUFFER;
             if (_Pickler_Write(self, &readonly_buffer_op, 1) < 0) {
                 goto error;
             }
         }
     }
 
-exit:
-    PyBuffer_Release(&keepalive_view);
+    PyBuffer_Release(&view);
     return rc;
 
 error:
-    PyBuffer_Release(&keepalive_view);
+    PyBuffer_Release(&view);
     return -1;
 }