From 35c91ec219b94b1d0d9269e6be6357f214f2e992 Mon Sep 17 00:00:00 2001
From: Cheng <zcbenz@gmail.com>
Date: Fri, 12 Apr 2024 10:52:12 +0900
Subject: [PATCH] Allow passing const pointers to js

---
 src/instance_data.h      |  2 +-
 src/prototype.h          | 17 +++++++++++++++--
 src/prototype_internal.h | 12 +++++++-----
 3 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/src/instance_data.h b/src/instance_data.h
index c82fbbc..e3a1ec7 100644
--- a/src/instance_data.h
+++ b/src/instance_data.h
@@ -16,7 +16,7 @@ namespace internal {
 // Get the base name of a type.
 template<typename T, typename Enable = void>
 struct TopClass {
-  static constexpr const char* name = Type<T>::name;
+  static constexpr const char* name = Type<std::remove_cv_t<T>>::name;
 };
 
 template<typename T>
diff --git a/src/prototype.h b/src/prototype.h
index 6980590..9bbea58 100644
--- a/src/prototype.h
+++ b/src/prototype.h
@@ -27,8 +27,9 @@ struct Type<Class<T>> {
 
 // Default converter for pointers.
 template<typename T>
-struct Type<T*, typename std::enable_if<std::is_class<T>::value &&
-                                        std::is_class<Type<T>>::value>::type> {
+struct Type<T*, std::enable_if_t<!std::is_const_v<T> &&
+                                 std::is_class_v<T> &&
+                                 std::is_class_v<Type<T>>>> {
   static constexpr const char* name = Type<T>::name;
   static inline napi_status ToNode(napi_env env, T* ptr, napi_value* result) {
     static_assert(internal::HasWrap<T>::value &&
@@ -89,6 +90,18 @@ struct Type<T*, typename std::enable_if<std::is_class<T>::value &&
   }
 };
 
+// Default converter for const pointers.
+template<typename T>
+struct Type<T*, std::enable_if_t<std::is_const_v<T> &&
+                                 std::is_class_v<T> &&
+                                 std::is_class_v<Type<T>>>> {
+  static constexpr const char* name = Type<std::decay_t<T>>::name;
+  static inline napi_status ToNode(napi_env env, T* ptr, napi_value* result) {
+    return ki::Type<std::decay_t<T>*>::ToNode(
+        env, const_cast<std::decay_t<T>*>(ptr), result);
+  }
+};
+
 }  // namespace ki
 
 #endif  // SRC_PROTOTYPE_H_
diff --git a/src/prototype_internal.h b/src/prototype_internal.h
index 491fb94..50b2954 100644
--- a/src/prototype_internal.h
+++ b/src/prototype_internal.h
@@ -38,27 +38,28 @@ template<typename, typename = void>
 struct HasWrap : std::false_type {};
 
 template<typename T>
-struct HasWrap<T, void_t<decltype(TypeBridge<T>::Wrap)>> : std::true_type {};
+struct HasWrap<T, void_t<decltype(TypeBridge<std::decay_t<T>>::Wrap)>>
+    : std::true_type {};
 
 template<typename, typename = void>
 struct HasUnwrap : std::false_type {};
 
 template<typename T>
-struct HasUnwrap<T, void_t<decltype(TypeBridge<T>::Unwrap)>>
+struct HasUnwrap<T, void_t<decltype(TypeBridge<std::decay_t<T>>::Unwrap)>>
     : std::true_type {};
 
 template<typename, typename = void>
 struct HasFinalize : std::false_type {};
 
 template<typename T>
-struct HasFinalize<T, void_t<decltype(TypeBridge<T>::Finalize)>>
+struct HasFinalize<T, void_t<decltype(TypeBridge<std::decay_t<T>>::Finalize)>>
     : std::true_type {};
 
 template<typename, typename = void>
 struct HasDestructor : std::false_type {};
 
 template<typename T>
-struct HasDestructor<T, void_t<decltype(Type<T>::Destructor)>>
+struct HasDestructor<T, void_t<decltype(Type<std::decay_t<T>>::Destructor)>>
     : std::true_type {};
 
 // Whether the JS object can be cached using the pointer as key.
@@ -70,7 +71,8 @@ template<typename, typename = void>
 struct CanCachePointer : std::true_type {};
 
 template<typename T>
-struct CanCachePointer<T, void_t<decltype(TypeBridge<T>::can_cache_pointer)>> {
+struct CanCachePointer<
+    T, void_t<decltype(TypeBridge<std::decay_t<T>>::can_cache_pointer)>> {
   static constexpr bool value = TypeBridge<T>::can_cache_pointer;
 };