py/scheduler: Allow selective handling in mp_handle_pending.

Extend mp_handle_pending to support three distinct behaviors via
mp_handle_pending_internal():

- MP_HANDLE_PENDING_CALLBACKS_ONLY: process callbacks only
- MP_HANDLE_PENDING_CALLBACKS_AND_EXCEPTIONS: callbacks + raise exceptions
- MP_HANDLE_PENDING_CALLBACKS_AND_CLEAR_EXCEPTIONS: callbacks + clear only

Original mp_handle_pending(bool) preserved as inline wrapper for
backward compatibility.

Signed-off-by: iabdalkader <[email protected]>

Author: iabdalkader

py/runtime.h

@@ -52,6 +52,12 @@ typedef enum {
     MP_ARG_KW_ONLY   = 0x200,
 } mp_arg_flag_t;
 
+typedef enum {
+    MP_HANDLE_PENDING_CALLBACKS_ONLY,
+    MP_HANDLE_PENDING_CALLBACKS_AND_EXCEPTIONS,
+    MP_HANDLE_PENDING_CALLBACKS_AND_CLEAR_EXCEPTIONS,
+} mp_handle_pending_behaviour_t;
+
 typedef union _mp_arg_val_t {
     bool u_bool;
     mp_int_t u_int;
@@ -100,7 +106,14 @@ void mp_sched_keyboard_interrupt(void);
 #if MICROPY_ENABLE_VM_ABORT
 void mp_sched_vm_abort(void);
 #endif
-void mp_handle_pending(bool raise_exc);
+
+void mp_handle_pending_internal(mp_handle_pending_behaviour_t behavior);
+
+static inline void mp_handle_pending(bool raise_exc) {
+    mp_handle_pending_internal(raise_exc ?
+        MP_HANDLE_PENDING_CALLBACKS_AND_EXCEPTIONS :
+        MP_HANDLE_PENDING_CALLBACKS_AND_CLEAR_EXCEPTIONS);
+}
 
 #if MICROPY_ENABLE_SCHEDULER
 void mp_sched_lock(void);

py/scheduler.c

@@ -213,24 +213,27 @@ MP_REGISTER_ROOT_POINTER(mp_sched_item_t sched_queue[MICROPY_SCHEDULER_DEPTH]);
 
 // Called periodically from the VM or from "waiting" code (e.g. sleep) to
 // process background tasks and pending exceptions (e.g. KeyboardInterrupt).
-void mp_handle_pending(bool raise_exc) {
+void mp_handle_pending_internal(mp_handle_pending_behaviour_t behavior) {
+    bool handle_exceptions = (behavior != MP_HANDLE_PENDING_CALLBACKS_ONLY);
+    bool raise_exceptions = (behavior == MP_HANDLE_PENDING_CALLBACKS_AND_EXCEPTIONS);
+
     // Handle pending VM abort.
     #if MICROPY_ENABLE_VM_ABORT
-    if (MP_STATE_VM(vm_abort) && mp_thread_is_main_thread()) {
+    if (handle_exceptions && MP_STATE_VM(vm_abort) && mp_thread_is_main_thread()) {
         MP_STATE_VM(vm_abort) = false;
-        if (raise_exc && nlr_get_abort() != NULL) {
+        if (raise_exceptions && nlr_get_abort() != NULL) {
             nlr_jump_abort();
         }
     }
     #endif
 
     // Handle any pending exception.
-    if (MP_STATE_THREAD(mp_pending_exception) != MP_OBJ_NULL) {
+    if (handle_exceptions && MP_STATE_THREAD(mp_pending_exception) != MP_OBJ_NULL) {
         mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
         mp_obj_t obj = MP_STATE_THREAD(mp_pending_exception);
         if (obj != MP_OBJ_NULL) {
             MP_STATE_THREAD(mp_pending_exception) = MP_OBJ_NULL;
-            if (raise_exc) {
+            if (raise_exceptions) {
                 MICROPY_END_ATOMIC_SECTION(atomic_state);
                 nlr_raise(obj);
             }