py/modthread: Add with-context capabilities to lock object.

py/modthread.c

@@ -95,10 +95,17 @@ STATIC mp_obj_t thread_lock_locked(mp_obj_t self_in) {
 }
 STATIC MP_DEFINE_CONST_FUN_OBJ_1(thread_lock_locked_obj, thread_lock_locked);
 
+STATIC mp_obj_t thread_lock___exit__(size_t n_args, const mp_obj_t *args) {
+    return thread_lock_release(args[0]);
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(thread_lock___exit___obj, 4, 4, thread_lock___exit__);
+
 STATIC const mp_rom_map_elem_t thread_lock_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_acquire), MP_ROM_PTR(&thread_lock_acquire_obj) },
     { MP_ROM_QSTR(MP_QSTR_release), MP_ROM_PTR(&thread_lock_release_obj) },
     { MP_ROM_QSTR(MP_QSTR_locked), MP_ROM_PTR(&thread_lock_locked_obj) },
+    { MP_ROM_QSTR(MP_QSTR___enter__), MP_ROM_PTR(&thread_lock_acquire_obj) },
+    { MP_ROM_QSTR(MP_QSTR___exit__), MP_ROM_PTR(&thread_lock___exit___obj) },
 };
 
 STATIC MP_DEFINE_CONST_DICT(thread_lock_locals_dict, thread_lock_locals_dict_table);