Decouple VariantImpl from ArrayImpl and ObjectImpl

src/ArduinoJson/Array/JsonArray.hpp

@@ -24,10 +24,11 @@ class JsonArray : public detail::VariantOperators<JsonArray> {
 
   // INTERNAL USE ONLY
   JsonArray(detail::VariantData* data, detail::ResourceManager* resources)
-      : impl_(detail::VariantImpl(data, resources).asArray()) {}
+      : impl_(data ? data->asArray() : nullptr, resources) {}
 
   // INTERNAL USE ONLY
-  JsonArray(const detail::ArrayImpl& impl) : impl_(impl) {}
+  JsonArray(detail::CollectionData* data, detail::ResourceManager* resources)
+      : impl_(data, resources) {}
 
   // Returns a JsonVariant pointing to the array.
   // https://arduinojson.org/v7/api/jsonvariant/

src/ArduinoJson/Array/JsonArrayConst.hpp

@@ -38,7 +38,7 @@ class JsonArrayConst : public detail::VariantOperators<JsonArrayConst> {
 
   // INTERNAL USE ONLY
   JsonArrayConst(detail::VariantData* data, detail::ResourceManager* resources)
-      : impl_(detail::VariantImpl(data, resources).asArray()) {}
+      : impl_(data ? data->asArray() : nullptr, resources) {}
 
   // INTERNAL USE ONLY
   JsonArrayConst(const detail::ArrayImpl& impl) : impl_(impl) {}

src/ArduinoJson/Json/JsonDeserializer.hpp

@@ -64,6 +64,8 @@ class JsonDeserializer {
       DeserializationOption::NestingLimit nestingLimit) {
     DeserializationError::Code err;
 
+    ARDUINOJSON_ASSERT(variant != nullptr);
+
     err = skipSpacesAndComments();
     if (err)
       return err;
@@ -71,15 +73,13 @@ class JsonDeserializer {
     switch (current()) {
       case '[':
         if (filter.allowArray())
-          return parseArray(VariantImpl(variant, resources_).toArray(), filter,
+          return parseArray(variant->toArray(), filter, nestingLimit);
-                            nestingLimit);
         else
           return skipArray(nestingLimit);
 
       case '{':
         if (filter.allowObject())
-          return parseObject(VariantImpl(variant, resources_).toObject(),
+          return parseObject(variant->toObject(), filter, nestingLimit);
-                             filter, nestingLimit);
         else
           return skipObject(nestingLimit);
 
@@ -148,7 +148,7 @@ class JsonDeserializer {
 
   template <typename TFilter>
   DeserializationError::Code parseArray(
-      ArrayImpl array, TFilter filter,
+      CollectionData* arrayData, TFilter filter,
       DeserializationOption::NestingLimit nestingLimit) {
     DeserializationError::Code err;
 
@@ -173,6 +173,8 @@ class JsonDeserializer {
     // Read each value
     for (;;) {
       if (elementFilter.allow()) {
+        ArrayImpl array(arrayData, resources_);
+
         // Allocate slot in array
         VariantData* value = array.addElement();
         if (!value)
@@ -234,7 +236,7 @@ class JsonDeserializer {
 
   template <typename TFilter>
   DeserializationError::Code parseObject(
-      ObjectImpl object, TFilter filter,
+      CollectionData* objectData, TFilter filter,
       DeserializationOption::NestingLimit nestingLimit) {
     DeserializationError::Code err;
 
@@ -275,6 +277,7 @@ class JsonDeserializer {
       TFilter memberFilter = filter[key];
 
       if (memberFilter.allow()) {
+        ObjectImpl object(objectData, resources_);
         auto member = object.getMember(adaptString(key));
         if (!member) {
           auto keyVariant = object.addPair(&member);

src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp

@@ -352,7 +352,7 @@ class MsgPackDeserializer {
     ArrayImpl array;
     if (allowArray) {
       ARDUINOJSON_ASSERT(variant != 0);
-      array = VariantImpl(variant, resources_).toArray();
+      array = ArrayImpl(variant->toArray(), resources_);
     }
 
     TFilter elementFilter = filter[0U];
@@ -388,7 +388,7 @@ class MsgPackDeserializer {
     ObjectImpl object;
     if (filter.allowObject()) {
       ARDUINOJSON_ASSERT(variant != 0);
-      object = VariantImpl(variant, resources_).toObject();
+      object = ObjectImpl(variant->toObject(), resources_);
     }
 
     for (; n; --n) {

src/ArduinoJson/Object/JsonObject.hpp

@@ -23,11 +23,12 @@ class JsonObject : public detail::VariantOperators<JsonObject> {
   JsonObject() {}
 
   // INTERNAL USE ONLY
-  JsonObject(const detail::ObjectImpl& impl) : impl_(impl) {}
+  JsonObject(detail::CollectionData* data, detail::ResourceManager* resource)
+      : impl_(data, resource) {}
 
   // INTERNAL USE ONLY
   JsonObject(detail::VariantData* data, detail::ResourceManager* resource)
-      : impl_(detail::VariantImpl(data, resource).asObject()) {}
+      : impl_(data ? data->asObject() : nullptr, resource) {}
 
   operator JsonVariant() const {
     return JsonVariant(getData(), getResourceManager());

src/ArduinoJson/Object/JsonObjectConst.hpp

@@ -23,7 +23,7 @@ class JsonObjectConst : public detail::VariantOperators<JsonObjectConst> {
 
   // INTERNAL USE ONLY
   JsonObjectConst(detail::VariantData* data, detail::ResourceManager* resources)
-      : impl_(detail::VariantImpl(data, resources).asObject()) {}
+      : impl_(data ? data->asObject() : nullptr, resources) {}
 
   // INTERNAL USE ONLY
   JsonObjectConst(const detail::ObjectImpl& impl) : impl_(impl) {}

src/ArduinoJson/Variant/VariantData.hpp

@@ -71,6 +71,19 @@ struct VariantData {
     content.asOwnedString = s;
   }
 
+  CollectionData* asCollection() {
+    return type & VariantTypeBits::CollectionMask ? &content.asCollection
+                                                  : nullptr;
+  }
+
+  CollectionData* asArray() {
+    return type == VariantType::Array ? &content.asCollection : nullptr;
+  }
+
+  CollectionData* asObject() {
+    return type == VariantType::Object ? &content.asCollection : nullptr;
+  }
+
   bool isFloat() const {
     return type & VariantTypeBits::NumberBit;
   }
@@ -79,6 +92,40 @@ struct VariantData {
     return type == VariantType::LinkedString ||
            type == VariantType::OwnedString || type == VariantType::TinyString;
   }
+
+  CollectionData* toArray() {
+    ARDUINOJSON_ASSERT(type == VariantType::Null);
+    type = VariantType::Array;
+    return new (&content.asCollection) CollectionData();
+  }
+
+  CollectionData* toObject() {
+    ARDUINOJSON_ASSERT(type == VariantType::Null);
+    type = VariantType::Object;
+    return new (&content.asCollection) CollectionData();
+  }
+
+  CollectionData* getOrCreateArray() {
+    switch (type) {
+      case VariantType::Null:
+        return toArray();
+      case VariantType::Array:
+        return &content.asCollection;
+      default:
+        return nullptr;
+    }
+  }
+
+  CollectionData* getOrCreateObject() {
+    switch (type) {
+      case VariantType::Null:
+        return toObject();
+      case VariantType::Object:
+        return &content.asCollection;
+      default:
+        return nullptr;
+    }
+  }
 };
 
 ARDUINOJSON_END_PRIVATE_NAMESPACE

src/ArduinoJson/Variant/VariantImpl.hpp

@@ -46,10 +46,11 @@ class VariantImpl {
 #endif
 
       case VariantType::Array:
-        return visit.visit(asArray());
+        return visit.visit(ArrayImpl(&data_->content.asCollection, resources_));
 
       case VariantType::Object:
-        return visit.visit(asObject());
+        return visit.visit(
+            ObjectImpl(&data_->content.asCollection, resources_));
 
       case VariantType::TinyString:
         return visit.visit(JsonString(data_->content.asTinyString));
@@ -88,14 +89,16 @@ class VariantImpl {
   }
 
   VariantData* addElement() {
-    auto array = isNull() ? toArray() : asArray();
+    if (!data_)
-    return array.addElement();
+      return nullptr;
+    return ArrayImpl(data_->getOrCreateArray(), resources_).addElement();
   }
 
   template <typename T>
   bool addValue(const T& value) {
-    auto array = isNull() ? toArray() : asArray();
+    if (!data_)
-    return array.addValue(value);
+      return false;
+    return ArrayImpl(data_->getOrCreateArray(), resources_).addValue(value);
   }
 
   bool asBoolean() const {
@@ -129,16 +132,6 @@ class VariantImpl {
     }
   }
 
-  ArrayImpl asArray() {
-    return ArrayImpl(isArray() ? &data_->content.asCollection : nullptr,
-                     resources_);
-  }
-
-  CollectionImpl asCollection() {
-    return CollectionImpl(
-        isCollection() ? &data_->content.asCollection : nullptr, resources_);
-  }
-
   template <typename T>
   T asFloat() const {
     if (!data_)
@@ -231,11 +224,6 @@ class VariantImpl {
     return parseNumber<T>(str);
   }
 
-  ObjectImpl asObject() {
-    return ObjectImpl(isObject() ? &data_->content.asCollection : nullptr,
-                      resources_);
-  }
-
   JsonString asRawString() const {
     switch (type()) {
       case VariantType::RawString:
@@ -274,25 +262,33 @@ class VariantImpl {
 #endif
 
   VariantData* getElement(size_t index) {
-    return asArray().getElement(index);
+    if (!data_)
+      return nullptr;
+    return ArrayImpl(data_->asArray(), resources_).getElement(index);
   }
 
   template <typename TAdaptedString>
   VariantData* getMember(TAdaptedString key) {
-    return asObject().getMember(key);
+    if (!data_)
+      return nullptr;
+    return ObjectImpl(data_->asObject(), resources_).getMember(key);
   }
 
   VariantData* getOrAddElement(size_t index) {
-    auto array = isNull() ? toArray() : asArray();
+    if (!data_)
-    return array.getOrAddElement(index);
+      return nullptr;
+    return ArrayImpl(data_->getOrCreateArray(), resources_)
+        .getOrAddElement(index);
   }
 
   template <typename TAdaptedString>
   VariantData* getOrAddMember(TAdaptedString key) {
     if (key.isNull())
       return nullptr;
-    auto obj = isNull() ? toObject() : asObject();
+    if (!data_)
-    return obj.getOrAddMember(key);
+      return nullptr;
+    return ObjectImpl(data_->getOrCreateObject(), resources_)
+        .getOrAddMember(key);
   }
 
   bool isArray() const {
@@ -352,16 +348,22 @@ class VariantImpl {
   }
 
   size_t nesting() {
-    return asCollection().nesting();
+    if (!data_)
+      return 0;
+    return CollectionImpl(data_->asCollection(), resources_).nesting();
   }
 
   void removeElement(size_t index) {
-    asArray().removeElement(index);
+    if (!data_)
+      return;
+    ArrayImpl(data_->asArray(), resources_).removeElement(index);
   }
 
   template <typename TAdaptedString>
   void removeMember(TAdaptedString key) {
-    asObject().removeMember(key);
+    if (!data_)
+      return;
+    ObjectImpl(data_->asObject(), resources_).removeMember(key);
   }
 
   bool setBoolean(bool value) {
@@ -466,31 +468,15 @@ class VariantImpl {
   bool setLinkedString(const char* s);
 
   size_t size() {
-    if (isObject())
-      return asObject().size();
-
-    if (isArray())
-      return asArray().size();
-
-    return 0;
-  }
-
-  ArrayImpl toArray() {
-    ARDUINOJSON_ASSERT(type() == VariantType::Null);  // must call clear() first
     if (!data_)
-      return ArrayImpl();
+      return 0;
-    data_->type = VariantType::Array;
-    return ArrayImpl(new (&data_->content.asCollection) CollectionData(),
-                     resources_);
-  }
 
-  ObjectImpl toObject() {
+    auto size = CollectionImpl(data_->asCollection(), resources_).size();
-    ARDUINOJSON_ASSERT(type() == VariantType::Null);  // must call clear() first
+
-    if (!data_)
+    if (data_->type == VariantType::Object)
-      return ObjectImpl();
+      size /= 2;
-    data_->type = VariantType::Object;
+
-    return ObjectImpl(new (&data_->content.asCollection) CollectionData(),
+    return size;
-                      resources_);
   }
 
   VariantType type() const {
@@ -566,7 +552,7 @@ inline void VariantImpl::clear() {
     resources_->freeEightByte(data_->content.asSlotId);
 #endif
 
-  asCollection().clear();
+  CollectionImpl(data_->asCollection(), resources_).clear();
 
   data_->type = VariantType::Null;
 }

src/ArduinoJson/Variant/VariantRefBaseImpl.hpp

@@ -147,17 +147,23 @@ inline bool VariantRefBase<TDerived>::doSet(const T& value, true_type) const {
 template <typename TDerived>
 template <typename T, enable_if_t<is_same<T, JsonArray>::value, int>>
 inline JsonArray VariantRefBase<TDerived>::to() const {
-  auto variant = getOrCreateVariantImpl();
+  auto data = getOrCreateData();
-  variant.clear();
+  if (!data)
-  return JsonArray(variant.toArray());
+    return JsonArray();
+  auto resources = getResourceManager();
+  VariantImpl(data, resources).clear();
+  return JsonArray(data->toArray(), resources);
 }
 
 template <typename TDerived>
 template <typename T, enable_if_t<is_same<T, JsonObject>::value, int>>
 JsonObject VariantRefBase<TDerived>::to() const {
-  auto variant = getOrCreateVariantImpl();
+  auto data = getOrCreateData();
-  variant.clear();
+  if (!data)
-  return JsonObject(variant.toObject());
+    return JsonObject();
+  auto resources = getResourceManager();
+  VariantImpl(data, resources).clear();
+  return JsonObject(data->toObject(), resources);
 }
 
 template <typename TDerived>