Fix pointer-backed struct marshalling

Author: DjDeveloperr

NativeScript/ffi/Interop.mm

@@ -994,7 +994,7 @@ napi_value interop_alloc(napi_env env, napi_callback_info info) {
   int64_t size;
   napi_get_value_int64(env, arg, &size);
 
-  void* data = malloc(size);
+  void* data = calloc(1, size);
   return Pointer::create(env, data);
 }
 

NativeScript/ffi/Struct.h

@@ -36,8 +36,11 @@ class StructObject {
   void* data;
   StructInfo* info;
   bool owned;
+  napi_env env = nullptr;
+  napi_ref backingRef = nullptr;
 
-  StructObject(StructInfo* info, void* data = nullptr);
+  StructObject(StructInfo* info, void* data = nullptr, napi_env env = nullptr,
+               napi_value backingValue = nullptr);
   StructObject(napi_env env, StructInfo* info, napi_value object,
                void* memory = nullptr);
 

NativeScript/ffi/Struct.mm

@@ -2,6 +2,7 @@
 #include <algorithm>
 #include <cstring>
 #include <vector>
+#include "Interop.h"
 #include "ObjCBridge.h"
 #include "TypeConv.h"
 #include "Util.h"
@@ -248,7 +249,23 @@ void StructObject_finalize(napi_env env, void* data, void* hint) {
   StructObject* object;
 
   if (argType == napi_object) {
-    object = new StructObject(env, info, arg);
+    if (Pointer::isInstance(env, arg)) {
+      Pointer* pointer = Pointer::unwrap(env, arg);
+      if (pointer == nullptr) {
+        napi_throw_error(env, nullptr, "Invalid pointer-backed struct argument");
+        return nullptr;
+      }
+      object = new StructObject(info, pointer->data, env, arg);
+    } else if (Reference::isInstance(env, arg)) {
+      Reference* reference = Reference::unwrap(env, arg);
+      if (reference == nullptr || reference->data == nullptr) {
+        napi_throw_error(env, nullptr, "Reference is not initialized");
+        return nullptr;
+      }
+      object = new StructObject(info, reference->data, env, arg);
+    } else {
+      object = new StructObject(env, info, arg);
+    }
   } else {
     object = new StructObject(info);
   }
@@ -324,8 +341,8 @@ void StructObject_finalize(napi_env env, void* data, void* hint) {
 
     StructObject* structObject = StructObject::unwrap(env, value);
     if (structObject != nullptr) {
-      size_t copySize = std::min(static_cast<size_t>(info->size),
-                                 static_cast<size_t>(structObject->info->size));
+      size_t copySize =
+          std::min(static_cast<size_t>(info->size), static_cast<size_t>(structObject->info->size));
       memcpy(out.data(), structObject->data, copySize);
       return true;
     }
@@ -353,20 +370,26 @@ void StructObject_finalize(napi_env env, void* data, void* hint) {
   return result;
 }
 
-inline StructObject::StructObject(StructInfo* info, void* data) {
+inline StructObject::StructObject(StructInfo* info, void* data, napi_env env,
+                                  napi_value backingValue) {
   this->info = info;
+  this->env = env;
   if (data == nullptr) {
     this->data = malloc(info->size);
     memset(this->data, 0, this->info->size);
     this->owned = true;
   } else {
     this->data = data;
     this->owned = false;
+    if (env != nullptr && backingValue != nullptr) {
+      napi_create_reference(env, backingValue, 1, &this->backingRef);
+    }
   }
 }
 
 StructObject::StructObject(napi_env env, StructInfo* info, napi_value object, void* memory) {
   this->info = info;
+  this->env = env;
 
   if (memory == nullptr) {
     this->owned = true;
@@ -376,6 +399,8 @@ void StructObject_finalize(napi_env env, void* data, void* hint) {
     this->data = memory;
   }
 
+  memset(this->data, 0, this->info->size);
+
   for (auto& field : info->fields) {
     bool hasProp = false;
     napi_has_named_property(env, object, field.name, &hasProp);
@@ -389,6 +414,9 @@ void StructObject_finalize(napi_env env, void* data, void* hint) {
 }
 
 StructObject::~StructObject() {
+  if (this->backingRef != nullptr && this->env != nullptr) {
+    napi_delete_reference(this->env, this->backingRef);
+  }
   if (this->owned) free(this->data);
 }