[smart_holder] Implement try_as_void_ptr_capsule as a free function (…

…#4539)

* Move try_as_void_ptr_capsule out from modified_type_caster_generic_load_impl.

* Try fixing clangtidy

include/pybind11/detail/smart_holder_type_casters.h

@@ -37,13 +37,37 @@ struct is_smart_holder_type<smart_holder> : std::true_type {};
 inline void register_instance(instance *self, void *valptr, const type_info *tinfo);
 inline bool deregister_instance(instance *self, void *valptr, const type_info *tinfo);
 
-// Replace all occurrences of a character in string.
-inline void replace_all(std::string &str, const std::string &from, char to) {
- size_t pos = str.find(from);
- while (pos != std::string::npos) {
- str.replace(pos, from.length(), 1, to);
- pos = str.find(from, pos);
+// Replace all occurrences of substrings in a string.
+inline void replace_all(std::string &str, const std::string &from, const std::string &to) {
+ if (str.empty()) {
+ return;
  }
+ size_t pos = 0;
+ while ((pos = str.find(from, pos)) != std::string::npos) {
+ str.replace(pos, from.length(), to);
+ pos += to.length();
+ }
+}
+
+inline void *try_as_void_ptr_capsule_get_pointer(handle src, const char *typeid_name) {
+ std::string type_name = typeid_name;
+ detail::clean_type_id(type_name);
+
+ // Convert `a::b::c` to `a_b_c`.
+ replace_all(type_name, "::", "_");
+ // Remove all `*` in the type name.
+ replace_all(type_name, "*", "");
+
+ std::string as_void_ptr_function_name("as_");
+ as_void_ptr_function_name += type_name;
+ if (hasattr(src, as_void_ptr_function_name.c_str())) {
+ auto as_void_ptr_function = function(src.attr(as_void_ptr_function_name.c_str()));
+ auto void_ptr_capsule = as_void_ptr_function();
+ if (isinstance<capsule>(void_ptr_capsule)) {
+ return reinterpret_borrow<capsule>(void_ptr_capsule).get_pointer();
+ }
+ }
+ return nullptr;
 }
 
 // The modified_type_caster_generic_load_impl could replace type_caster_generic::load_impl but not
@@ -120,22 +144,10 @@ class modified_type_caster_generic_load_impl {
  }
 
  bool try_as_void_ptr_capsule(handle src) {
- std::string type_name = cpptype->name();
- detail::clean_type_id(type_name);
-
- // Convert `a::b::c` to `a_b_c`
- replace_all(type_name, "::", '_');
-
- std::string as_void_ptr_function_name("as_");
- as_void_ptr_function_name += type_name;
- if (hasattr(src, as_void_ptr_function_name.c_str())) {
- auto as_void_ptr_function = function(src.attr(as_void_ptr_function_name.c_str()));
- auto void_ptr_capsule = as_void_ptr_function();
- if (isinstance<capsule>(void_ptr_capsule)) {
- unowned_void_ptr_from_void_ptr_capsule
- = reinterpret_borrow<capsule>(void_ptr_capsule).get_pointer();
- return true;
- }
+ unowned_void_ptr_from_void_ptr_capsule
+ = try_as_void_ptr_capsule_get_pointer(src, cpptype->name());
+ if (unowned_void_ptr_from_void_ptr_capsule != nullptr) {
+ return true;
  }
  return false;
  }