Implement variant copy at the JsonVariant level

src/ArduinoJson.hpp

@@ -42,6 +42,7 @@
 #include "ArduinoJson/Object/MemberProxy.hpp"
 #include "ArduinoJson/Object/ObjectImpl.hpp"
 #include "ArduinoJson/Variant/ConverterImpl.hpp"
+#include "ArduinoJson/Variant/JsonVariantCopier.hpp"
 #include "ArduinoJson/Variant/VariantCompare.hpp"
 
 #include "ArduinoJson/Json/JsonDeserializer.hpp"

src/ArduinoJson/Array/ArrayImpl.hpp

@@ -24,9 +24,8 @@ inline bool ArrayData::copyFrom(const ArrayData& src,
 
   for (auto it = src.createIterator(); !it.done(); it.next()) {
     auto var = addElement(resources);
-    if (!var)
+    if (!copyVariant(JsonVariant(var, resources),
-      return false;
+                     JsonVariantConst(it.data(), resources)))
-    if (!var->copyFrom(*it, resources))
       return false;
   }
   return true;

src/ArduinoJson/Object/ObjectImpl.hpp

@@ -18,9 +18,8 @@ inline bool ObjectData::copyFrom(const ObjectData& src,
     JsonString key(it.key(),
                    it.ownsKey() ? JsonString::Copied : JsonString::Linked);
     auto var = addMember(adaptString(key), resources);
-    if (!var)
+    if (!copyVariant(JsonVariant(var, resources),
-      return false;
+                     JsonVariantConst(it.data(), resources)))
-    if (!var->copyFrom(*it, resources))
       return false;
   }
   return true;

src/ArduinoJson/Variant/ConverterImpl.hpp

@@ -302,9 +302,11 @@ struct ConverterNeedsWriteableRef {
 
 template <>
 struct Converter<JsonArrayConst> : private detail::VariantAttorney {
-  static void toJson(JsonVariantConst src, JsonVariant dst) {
+  static void toJson(JsonArrayConst src, JsonVariant dst) {
-    detail::VariantData::copy(getData(dst), getData(src),
+    if (src.isNull())
-                              getResourceManager(dst));
+      dst.set(nullptr);
+    else
+      dst.to<JsonArray>().set(src);
   }
 
   static JsonArrayConst fromJson(JsonVariantConst src) {
@@ -322,8 +324,10 @@ struct Converter<JsonArrayConst> : private detail::VariantAttorney {
 template <>
 struct Converter<JsonArray> : private detail::VariantAttorney {
   static void toJson(JsonVariantConst src, JsonVariant dst) {
-    detail::VariantData::copy(getData(dst), getData(src),
+    if (src.isNull())
-                              getResourceManager(dst));
+      dst.set(nullptr);
+    else
+      dst.to<JsonArray>().set(src);
   }
 
   static JsonArray fromJson(JsonVariant src) {
@@ -348,8 +352,10 @@ struct Converter<JsonArray> : private detail::VariantAttorney {
 template <>
 struct Converter<JsonObjectConst> : private detail::VariantAttorney {
   static void toJson(JsonVariantConst src, JsonVariant dst) {
-    detail::VariantData::copy(getData(dst), getData(src),
+    if (src.isNull())
-                              getResourceManager(dst));
+      dst.set(nullptr);
+    else
+      dst.to<JsonObject>().set(src);
   }
 
   static JsonObjectConst fromJson(JsonVariantConst src) {
@@ -367,8 +373,10 @@ struct Converter<JsonObjectConst> : private detail::VariantAttorney {
 template <>
 struct Converter<JsonObject> : private detail::VariantAttorney {
   static void toJson(JsonVariantConst src, JsonVariant dst) {
-    detail::VariantData::copy(getData(dst), getData(src),
+    if (src.isNull())
-                              getResourceManager(dst));
+      dst.set(nullptr);
+    else
+      dst.to<JsonObject>().set(src);
   }
 
   static JsonObject fromJson(JsonVariant src) {

src/ArduinoJson/Variant/JsonVariant.hpp

@@ -39,11 +39,14 @@ class JsonVariant : public detail::VariantRefBase<JsonVariant>,
   detail::ResourceManager* resources_;
 };
 
+namespace detail {
+bool copyVariant(JsonVariant dst, JsonVariantConst src);
+}
+
 template <>
 struct Converter<JsonVariant> : private detail::VariantAttorney {
   static void toJson(JsonVariant src, JsonVariant dst) {
-    detail::VariantData::copy(getData(dst), getData(src),
+    copyVariant(dst, src);
-                              getResourceManager(dst));
   }
 
   static JsonVariant fromJson(JsonVariant src) {
@@ -66,8 +69,7 @@ struct Converter<JsonVariant> : private detail::VariantAttorney {
 template <>
 struct Converter<JsonVariantConst> : private detail::VariantAttorney {
   static void toJson(JsonVariantConst src, JsonVariant dst) {
-    detail::VariantData::copy(getData(dst), getData(src),
+    copyVariant(dst, src);
-                              getResourceManager(dst));
   }
 
   static JsonVariantConst fromJson(JsonVariantConst src) {

src/ArduinoJson/Variant/JsonVariantCopier.hpp

@@ -0,0 +1,34 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2023, Benoit BLANCHON
+// MIT License
+
+#pragma once
+
+#include <ArduinoJson/Variant/JsonVariant.hpp>
+#include <ArduinoJson/Variant/JsonVariantVisitor.hpp>
+
+ARDUINOJSON_BEGIN_PRIVATE_NAMESPACE
+
+class JsonVariantCopier {
+ public:
+  typedef bool result_type;
+
+  JsonVariantCopier(JsonVariant dst) : dst_(dst) {}
+
+  template <typename T>
+  bool visit(T src) {
+    return dst_.set(src);
+  }
+
+ private:
+  JsonVariant dst_;
+};
+
+inline bool copyVariant(JsonVariant dst, JsonVariantConst src) {
+  if (dst.isUnbound())
+    return false;
+  JsonVariantCopier copier(dst);
+  return accept(src, copier);
+}
+
+ARDUINOJSON_END_PRIVATE_NAMESPACE

src/ArduinoJson/Variant/VariantData.hpp

@@ -185,47 +185,6 @@ class VariantData {
     }
   }
 
-  bool copyFrom(const VariantData& src, ResourceManager* resources) {
-    release(resources);
-    switch (src.type()) {
-      case VALUE_IS_ARRAY:
-        return toArray().copyFrom(src.content_.asArray, resources);
-      case VALUE_IS_OBJECT:
-        return toObject().copyFrom(src.content_.asObject, resources);
-      case VALUE_IS_OWNED_STRING: {
-        auto str = adaptString(src.asString());
-        auto dup = resources->saveString(str);
-        if (!dup)
-          return false;
-        setOwnedString(dup);
-        return true;
-      }
-      case VALUE_IS_RAW_STRING: {
-        auto str = adaptString(src.asRawString());
-        auto dup = resources->saveString(str);
-        if (!dup)
-          return false;
-        setRawString(dup);
-        return true;
-      }
-      default:
-        content_ = src.content_;
-        flags_ = src.flags_;
-        return true;
-    }
-  }
-
-  static bool copy(VariantData* dst, const VariantData* src,
-                   ResourceManager* resources) {
-    if (!dst)
-      return false;
-    if (!src) {
-      dst->setNull();
-      return true;
-    }
-    return dst->copyFrom(*src, resources);
-  }
-
   VariantData* getElement(size_t index) const {
     auto array = asArray();
     if (!array)