Extract `ArrayData` from `CollectionData`

src/ArduinoJson.hpp

@@ -32,6 +32,7 @@
 
 #include "ArduinoJson/Document/JsonDocument.hpp"
 
+#include "ArduinoJson/Array/ArrayImpl.hpp"
 #include "ArduinoJson/Array/ElementProxy.hpp"
 #include "ArduinoJson/Array/JsonArrayImpl.hpp"
 #include "ArduinoJson/Array/Utilities.hpp"

src/ArduinoJson/Array/ArrayData.hpp

@@ -0,0 +1,65 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2023, Benoit BLANCHON
+// MIT License
+
+#pragma once
+
+#include <ArduinoJson/Collection/CollectionData.hpp>
+
+ARDUINOJSON_BEGIN_PRIVATE_NAMESPACE
+
+class ArrayData : public CollectionData {
+ public:
+  VariantData* addElement(ResourceManager* resources);
+
+  static VariantData* addElement(ArrayData* array, ResourceManager* resources) {
+    if (!array)
+      return nullptr;
+    return array->addElement(resources);
+  }
+
+  VariantData* getOrAddElement(size_t index, ResourceManager* resources);
+
+  VariantData* getElement(size_t index) const;
+
+  static VariantData* getElement(const ArrayData* array, size_t index) {
+    if (!array)
+      return nullptr;
+    return array->getElement(index);
+  }
+
+  void removeElement(size_t index, ResourceManager* resources);
+
+  static void removeElement(ArrayData* array, size_t index,
+                            ResourceManager* resources) {
+    if (!array)
+      return;
+    array->removeElement(index, resources);
+  }
+
+  bool equals(const ArrayData&) const;
+
+  static bool equals(const ArrayData* lhs, const ArrayData* rhs) {
+    if (lhs == rhs)
+      return true;
+    if (!lhs || !rhs)
+      return false;
+
+    return lhs->equals(*rhs);
+  }
+
+  bool copyFrom(const ArrayData& src, ResourceManager* resources);
+
+  static bool copy(ArrayData* dst, const ArrayData* src,
+                   ResourceManager* resources) {
+    if (!dst || !src)
+      return false;
+
+    return dst->copyFrom(*src, resources);
+  }
+
+ private:
+  VariantSlot* getSlot(size_t index) const;
+};
+
+ARDUINOJSON_END_PRIVATE_NAMESPACE

src/ArduinoJson/Array/ArrayImpl.hpp

@@ -0,0 +1,81 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright © 2014-2023, Benoit BLANCHON
+// MIT License
+
+#pragma once
+
+#include <ArduinoJson/Array/ArrayData.hpp>
+#include <ArduinoJson/Variant/VariantCompare.hpp>
+
+ARDUINOJSON_BEGIN_PRIVATE_NAMESPACE
+
+inline VariantData* ArrayData::addElement(ResourceManager* resources) {
+  auto slot = resources->allocVariant();
+  if (!slot)
+    return nullptr;
+  addSlot(slot);
+  return slot->data();
+}
+
+inline bool ArrayData::copyFrom(const ArrayData& src,
+                                ResourceManager* resources) {
+  clear(resources);
+
+  for (VariantSlot* s = src.head(); s; s = s->next()) {
+    auto var = addElement(resources);
+    if (!variantCopyFrom(var, s->data(), resources))
+      return false;
+  }
+  return true;
+}
+
+inline bool ArrayData::equals(const ArrayData& other) const {
+  auto a = head();
+  auto b = other.head();
+
+  for (;;) {
+    if (!a && !b)  // both ended
+      return true;
+    if (!a || !b)  // one ended
+      return false;
+    if (compare(a->data(), b->data()) != COMPARE_RESULT_EQUAL)
+      return false;
+    a = a->next();
+    b = b->next();
+  }
+}
+
+inline VariantData* ArrayData::getOrAddElement(size_t index,
+                                               ResourceManager* resources) {
+  VariantSlot* slot = head();
+  while (slot && index > 0) {
+    slot = slot->next();
+    index--;
+  }
+  if (!slot)
+    index++;
+  while (index > 0) {
+    slot = resources->allocVariant();
+    if (!slot)
+      return nullptr;
+    addSlot(slot);
+    index--;
+  }
+  return slot->data();
+}
+
+inline VariantData* ArrayData::getElement(size_t index) const {
+  return slotData(getSlot(index));
+}
+
+inline VariantSlot* ArrayData::getSlot(size_t index) const {
+  if (!head())
+    return 0;
+  return head()->next(index);
+}
+
+inline void ArrayData::removeElement(size_t index, ResourceManager* resources) {
+  removeSlot(getSlot(index), resources);
+}
+
+ARDUINOJSON_END_PRIVATE_NAMESPACE

src/ArduinoJson/Array/JsonArray.hpp

@@ -24,7 +24,7 @@ class JsonArray : public detail::VariantOperators<JsonArray> {
   FORCE_INLINE JsonArray() : data_(0), resources_(0) {}
 
   // INTERNAL USE ONLY
-  FORCE_INLINE JsonArray(detail::CollectionData* data,
+  FORCE_INLINE JsonArray(detail::ArrayData* data,
                          detail::ResourceManager* resources)
       : data_(data), resources_(resources) {}
 
@@ -46,7 +46,8 @@ class JsonArray : public detail::VariantOperators<JsonArray> {
   // Returns a reference to the new element.
   // https://arduinojson.org/v6/api/jsonarray/add/
   JsonVariant add() const {
-    return JsonVariant(collectionAddElement(data_, resources_), resources_);
+    return JsonVariant(detail::ArrayData::addElement(data_, resources_),
+                       resources_);
   }
 
   // Appends a value to the array.
@@ -80,12 +81,12 @@ class JsonArray : public detail::VariantOperators<JsonArray> {
   // Copies an array.
   // https://arduinojson.org/v6/api/jsonarray/set/
   FORCE_INLINE bool set(JsonArrayConst src) const {
-    return collectionCopy(data_, src.data_, resources_);
+    return detail::ArrayData::copy(data_, src.data_, resources_);
   }
 
   // Compares the content of two arrays.
   FORCE_INLINE bool operator==(JsonArray rhs) const {
-    return arrayEquals(data_, rhs.data_);
+    return detail::ArrayData::equals(data_, rhs.data_);
   }
 
   // Removes the element at the specified iterator.
@@ -99,7 +100,7 @@ class JsonArray : public detail::VariantOperators<JsonArray> {
   // ⚠️ Doesn't release the memory associated with the removed element.
   // https://arduinojson.org/v6/api/jsonarray/remove/
   FORCE_INLINE void remove(size_t index) const {
-    collectionRemoveElement(data_, index, resources_);
+    detail::ArrayData::removeElement(data_, index, resources_);
   }
 
   // Removes all the elements of the array.
@@ -172,7 +173,7 @@ class JsonArray : public detail::VariantOperators<JsonArray> {
     return collectionToVariant(data_);
   }
 
-  detail::CollectionData* data_;
+  detail::ArrayData* data_;
   detail::ResourceManager* resources_;
 };
 

src/ArduinoJson/Array/JsonArrayConst.hpp

@@ -40,19 +40,18 @@ class JsonArrayConst : public detail::VariantOperators<JsonArrayConst> {
   FORCE_INLINE JsonArrayConst() : data_(0) {}
 
   // INTERNAL USE ONLY
-  FORCE_INLINE JsonArrayConst(const detail::CollectionData* data)
-      : data_(data) {}
+  FORCE_INLINE JsonArrayConst(const detail::ArrayData* data) : data_(data) {}
 
   // Compares the content of two arrays.
   // Returns true if the two arrays are equal.
   FORCE_INLINE bool operator==(JsonArrayConst rhs) const {
-    return arrayEquals(data_, rhs.data_);
+    return detail::ArrayData::equals(data_, rhs.data_);
   }
 
   // Returns the element at the specified index.
   // https://arduinojson.org/v6/api/jsonarrayconst/subscript/
   FORCE_INLINE JsonVariantConst operator[](size_t index) const {
-    return JsonVariantConst(collectionGetElement(data_, index));
+    return JsonVariantConst(detail::ArrayData::getElement(data_, index));
   }
 
   operator JsonVariantConst() const {
@@ -94,7 +93,7 @@ class JsonArrayConst : public detail::VariantOperators<JsonArrayConst> {
     return collectionToVariant(data_);
   }
 
-  const detail::CollectionData* data_;
+  const detail::ArrayData* data_;
 };
 
 template <>

src/ArduinoJson/Collection/CollectionData.hpp

@@ -29,8 +29,6 @@ class CollectionData {
   size_t memoryUsage() const;
   size_t size() const;
 
-  VariantData* addElement(ResourceManager* resources);
-
   VariantData* addMember(StringNode* key, ResourceManager* resources);
 
   template <typename TAdaptedString>
@@ -39,10 +37,6 @@ class CollectionData {
   void clear(ResourceManager* resources);
   bool copyFrom(const CollectionData& src, ResourceManager* resources);
 
-  VariantData* getOrAddElement(size_t index, ResourceManager* resources);
-
-  VariantData* getElement(size_t index) const;
-
   template <typename TAdaptedString>
   VariantData* getOrAddMember(TAdaptedString key, ResourceManager* resources);
 
@@ -51,8 +45,6 @@ class CollectionData {
 
   void removeSlot(VariantSlot* slot, ResourceManager* resources);
 
-  void removeElement(size_t index, ResourceManager* resources);
-
   template <typename TAdaptedString>
   void removeMember(TAdaptedString key, ResourceManager* resources);
 
@@ -62,15 +54,14 @@ class CollectionData {
 
   void movePointers(ptrdiff_t variantDistance);
 
- private:
+ protected:
   void addSlot(VariantSlot*);
 
-  VariantSlot* getPreviousSlot(VariantSlot*) const;
-
-  VariantSlot* getSlot(size_t index) const;
-
   template <typename TAdaptedString>
   VariantSlot* getSlot(TAdaptedString key) const;
+
+ private:
+  VariantSlot* getPreviousSlot(VariantSlot*) const;
 };
 
 inline const VariantData* collectionToVariant(
@@ -84,10 +75,6 @@ inline VariantData* collectionToVariant(CollectionData* collection) {
   return reinterpret_cast<VariantData*>(data);
 }
 
-bool arrayEquals(const detail::CollectionData& lhs,
-                 const detail::CollectionData& rhs);
-bool arrayEquals(const detail::CollectionData* lhs,
-                 const detail::CollectionData* rhs);
 bool objectEquals(const detail::CollectionData& lhs,
                   const detail::CollectionData& rhs);
 bool objectEquals(const detail::CollectionData* lhs,

src/ArduinoJson/Collection/CollectionFunctions.hpp

@@ -8,20 +8,6 @@
 
 ARDUINOJSON_BEGIN_PRIVATE_NAMESPACE
 
-inline VariantData* collectionAddElement(CollectionData* array,
-                                         ResourceManager* resources) {
-  if (!array)
-    return nullptr;
-  return array->addElement(resources);
-}
-
-template <typename TAdaptedString>
-inline VariantData* collectionAddMember(CollectionData* obj, TAdaptedString key,
-                                        ResourceManager* resources) {
-  ARDUINOJSON_ASSERT(obj != nullptr);
-  return obj->addMember(key, resources);
-}
-
 inline void collectionClear(CollectionData* c, ResourceManager* resources) {
   if (!c)
     return;
@@ -36,13 +22,6 @@ inline bool collectionCopy(CollectionData* dst, const CollectionData* src,
   return dst->copyFrom(*src, resources);
 }
 
-inline VariantData* collectionGetElement(const CollectionData* obj,
-                                         size_t index) {
-  if (!obj)
-    return nullptr;
-  return obj->getElement(index);
-}
-
 template <typename TAdaptedString>
 inline VariantData* collectionGetMember(const CollectionData* obj,
                                         TAdaptedString key) {
@@ -58,13 +37,6 @@ inline void collectionRemove(CollectionData* data, VariantSlot* slot,
   data->removeSlot(slot, resources);
 }
 
-inline void collectionRemoveElement(CollectionData* array, size_t index,
-                                    ResourceManager* resources) {
-  if (!array)
-    return;
-  array->removeElement(index, resources);
-}
-
 template <typename TAdaptedString>
 inline void collectionRemoveMember(CollectionData* obj, TAdaptedString key,
                                    ResourceManager* resources) {

src/ArduinoJson/Collection/CollectionImpl.hpp

@@ -23,14 +23,6 @@ inline void CollectionData::addSlot(VariantSlot* slot) {
   }
 }
 
-inline VariantData* CollectionData::addElement(ResourceManager* resources) {
-  auto slot = resources->allocVariant();
-  if (!slot)
-    return nullptr;
-  addSlot(slot);
-  return slot->data();
-}
-
 inline VariantData* CollectionData::addMember(StringNode* key,
                                               ResourceManager* resources) {
   ARDUINOJSON_ASSERT(key != nullptr);
@@ -67,25 +59,6 @@ inline VariantData* CollectionData::getMember(TAdaptedString key) const {
   return slotData(getSlot(key));
 }
 
-inline VariantData* CollectionData::getOrAddElement(
-    size_t index, ResourceManager* resources) {
-  VariantSlot* slot = head_;
-  while (slot && index > 0) {
-    slot = slot->next();
-    index--;
-  }
-  if (!slot)
-    index++;
-  while (index > 0) {
-    slot = resources->allocVariant();
-    if (!slot)
-      return nullptr;
-    addSlot(slot);
-    index--;
-  }
-  return slot->data();
-}
-
 template <typename TAdaptedString>
 VariantData* CollectionData::getOrAddMember(TAdaptedString key,
                                             ResourceManager* resources) {
@@ -95,10 +68,6 @@ VariantData* CollectionData::getOrAddMember(TAdaptedString key,
   return addMember(key, resources);
 }
 
-inline VariantData* CollectionData::getElement(size_t index) const {
-  return slotData(getSlot(index));
-}
-
 inline void CollectionData::clear(ResourceManager* resources) {
   for (auto slot = head_; slot; slot = slot->next())
     slotRelease(slot, resources);
@@ -111,14 +80,10 @@ inline bool CollectionData::copyFrom(const CollectionData& src,
   clear(resources);
 
   for (VariantSlot* s = src.head(); s; s = s->next()) {
-    VariantData* var;
-    if (s->key() != 0) {
-      JsonString key(s->key(),
-                     s->ownsKey() ? JsonString::Copied : JsonString::Linked);
-      var = addMember(adaptString(key), resources);
-    } else {
-      var = addElement(resources);
-    }
+    ARDUINOJSON_ASSERT(s->key() != 0);
+    JsonString key(s->key(),
+                   s->ownsKey() ? JsonString::Copied : JsonString::Linked);
+    auto var = addMember(adaptString(key), resources);
     if (!variantCopyFrom(var, s->data(), resources))
       return false;
   }
@@ -138,12 +103,6 @@ inline VariantSlot* CollectionData::getSlot(TAdaptedString key) const {
   return slot;
 }
 
-inline VariantSlot* CollectionData::getSlot(size_t index) const {
-  if (!head_)
-    return 0;
-  return head_->next(index);
-}
-
 inline VariantSlot* CollectionData::getPreviousSlot(VariantSlot* target) const {
   VariantSlot* current = head_;
   while (current) {
@@ -170,11 +129,6 @@ inline void CollectionData::removeSlot(VariantSlot* slot,
   slotRelease(slot, resources);
 }
 
-inline void CollectionData::removeElement(size_t index,
-                                          ResourceManager* resources) {
-  removeSlot(getSlot(index), resources);
-}
-
 template <typename TAdaptedString>
 inline void CollectionData::removeMember(TAdaptedString key,
                                          ResourceManager* resources) {
@@ -211,31 +165,6 @@ inline void CollectionData::movePointers(ptrdiff_t variantDistance) {
     slot->data()->movePointers(variantDistance);
 }
 
-inline bool arrayEquals(const CollectionData& lhs, const CollectionData& rhs) {
-  auto a = lhs.head();
-  auto b = rhs.head();
-
-  for (;;) {
-    if (!a && !b)  // both ended
-      return true;
-    if (!a || !b)  // one ended
-      return false;
-    if (compare(a->data(), b->data()) != COMPARE_RESULT_EQUAL)
-      return false;
-    a = a->next();
-    b = b->next();
-  }
-}
-
-inline bool arrayEquals(const CollectionData* lhs, const CollectionData* rhs) {
-  if (lhs == rhs)
-    return true;
-  if (!lhs || !rhs)
-    return false;
-
-  return arrayEquals(*lhs, *rhs);
-}
-
 inline bool objectEquals(const CollectionData& lhs, const CollectionData& rhs) {
   size_t count = 0;
   for (auto a = lhs.head(); a; a = a->next()) {

src/ArduinoJson/Json/JsonDeserializer.hpp

@@ -146,7 +146,7 @@ class JsonDeserializer {
 
   template <typename TFilter>
   DeserializationError::Code parseArray(
-      CollectionData& array, TFilter filter,
+      ArrayData& array, TFilter filter,
       DeserializationOption::NestingLimit nestingLimit) {
     DeserializationError::Code err;
 
@@ -172,7 +172,7 @@ class JsonDeserializer {
     for (;;) {
       if (elementFilter.allow()) {
         // Allocate slot in array
-        VariantData* value = collectionAddElement(&array, resources_);
+        VariantData* value = array.addElement(resources_);
         if (!value)
           return DeserializationError::NoMemory;
 

src/ArduinoJson/Json/JsonSerializer.hpp

@@ -18,7 +18,7 @@ class JsonSerializer : public Visitor<size_t> {
 
   JsonSerializer(TWriter writer) : formatter_(writer) {}
 
-  FORCE_INLINE size_t visitArray(const CollectionData& array) {
+  FORCE_INLINE size_t visitArray(const ArrayData& array) {
     write('[');
 
     const VariantSlot* slot = array.head();

src/ArduinoJson/Json/PrettyJsonSerializer.hpp

@@ -18,7 +18,7 @@ class PrettyJsonSerializer : public JsonSerializer<TWriter> {
  public:
   PrettyJsonSerializer(TWriter writer) : base(writer), nesting_(0) {}
 
-  size_t visitArray(const CollectionData& array) {
+  size_t visitArray(const ArrayData& array) {
     const VariantSlot* slot = array.head();
     if (slot) {
       base::write("[\r\n");

src/ArduinoJson/MsgPack/MsgPackDeserializer.hpp

@@ -419,7 +419,7 @@ class MsgPackDeserializer {
 
     bool allowArray = filter.allowArray();
 
-    CollectionData* array;
+    ArrayData* array;
     if (allowArray) {
       ARDUINOJSON_ASSERT(variant != 0);
       array = &variant->toArray();
@@ -434,7 +434,7 @@ class MsgPackDeserializer {
 
       if (elementFilter.allow()) {
         ARDUINOJSON_ASSERT(array != 0);
-        value = collectionAddElement(array, resources_);
+        value = array->addElement(resources_);
         if (!value)
           return DeserializationError::NoMemory;
       } else {

src/ArduinoJson/MsgPack/MsgPackSerializer.hpp

@@ -44,7 +44,7 @@ class MsgPackSerializer : public Visitor<size_t> {
     return bytesWritten();
   }
 
-  size_t visitArray(const CollectionData& array) {
+  size_t visitArray(const ArrayData& array) {
     size_t n = array.size();
     if (n < 0x10) {
       writeByte(uint8_t(0x90 + array.size()));

src/ArduinoJson/Variant/VariantCompare.hpp

@@ -79,12 +79,12 @@ struct Comparer<decltype(nullptr), void> : NullComparer {
 };
 
 struct ArrayComparer : ComparerBase {
-  const CollectionData* rhs_;
+  const ArrayData* rhs_;
 
-  explicit ArrayComparer(const CollectionData& rhs) : rhs_(&rhs) {}
+  explicit ArrayComparer(const ArrayData& rhs) : rhs_(&rhs) {}
 
-  CompareResult visitArray(const CollectionData& lhs) {
-    if (arrayEquals(lhs, *rhs_))
+  CompareResult visitArray(const ArrayData& lhs) {
+    if (rhs_->equals(lhs))
       return COMPARE_RESULT_EQUAL;
     else
       return COMPARE_RESULT_DIFFER;
@@ -128,7 +128,7 @@ struct VariantComparer : ComparerBase {
 
   explicit VariantComparer(const VariantData* value) : rhs(value) {}
 
-  CompareResult visitArray(const CollectionData& lhs) {
+  CompareResult visitArray(const ArrayData& lhs) {
     ArrayComparer comparer(lhs);
     return accept(comparer);
   }

src/ArduinoJson/Variant/VariantContent.hpp

@@ -6,10 +6,12 @@
 
 #include <stddef.h>  // size_t
 
+#include <ArduinoJson/Array/ArrayData.hpp>
 #include <ArduinoJson/Collection/CollectionData.hpp>
 #include <ArduinoJson/Numbers/JsonFloat.hpp>
 #include <ArduinoJson/Numbers/JsonInteger.hpp>
 
+
 ARDUINOJSON_BEGIN_PRIVATE_NAMESPACE
 
 enum {
@@ -45,6 +47,7 @@ union VariantContent {
   JsonUInt asUnsignedInteger;
   JsonInteger asSignedInteger;
   CollectionData asCollection;
+  ArrayData asArray;
   const char* asLinkedString;
   struct StringNode* asOwnedString;
 };

src/ArduinoJson/Variant/VariantData.hpp

@@ -14,12 +14,8 @@
 
 ARDUINOJSON_BEGIN_PRIVATE_NAMESPACE
 
-VariantData* collectionAddElement(CollectionData* array,
-                                  ResourceManager* resources);
 bool collectionCopy(CollectionData* dst, const CollectionData* src,
                     ResourceManager* resources);
-void collectionRemoveElement(CollectionData* data, size_t index,
-                             ResourceManager* resources);
 template <typename T>
 T parseNumber(const char* s);
 void slotRelease(VariantSlot* slot, ResourceManager* resources);
@@ -38,7 +34,7 @@ class VariantData {
         return visitor.visitFloat(content_.asFloat);
 
       case VALUE_IS_ARRAY:
-        return visitor.visitArray(content_.asCollection);
+        return visitor.visitArray(content_.asArray);
 
       case VALUE_IS_OBJECT:
         return visitor.visitObject(content_.asCollection);
@@ -71,7 +67,7 @@ class VariantData {
 
   VariantData* addElement(ResourceManager* resources) {
     auto array = isNull() ? &toArray() : asArray();
-    return collectionAddElement(array, resources);
+    return detail::ArrayData::addElement(array, resources);
   }
 
   bool asBoolean() const {
@@ -90,11 +86,11 @@ class VariantData {
     }
   }
 
-  CollectionData* asArray() {
-    return isArray() ? &content_.asCollection : 0;
+  ArrayData* asArray() {
+    return isArray() ? &content_.asArray : 0;
   }
 
-  const CollectionData* asArray() const {
+  const ArrayData* asArray() const {
     return const_cast<VariantData*>(this)->asArray();
   }
 
@@ -181,7 +177,7 @@ class VariantData {
     }
     switch (src->type()) {
       case VALUE_IS_ARRAY:
-        return collectionCopy(&toArray(), src->asArray(), resources);
+        return toArray().copyFrom(*src->asArray(), resources);
       case VALUE_IS_OBJECT:
         return collectionCopy(&toObject(), src->asObject(), resources);
       case VALUE_IS_OWNED_STRING: {
@@ -319,7 +315,7 @@ class VariantData {
   }
 
   void removeElement(size_t index, ResourceManager* resources) {
-    collectionRemoveElement(asArray(), index, resources);
+    ArrayData::removeElement(asArray(), index, resources);
   }
 
   template <typename TAdaptedString>
@@ -427,13 +423,13 @@ class VariantData {
     return isCollection() ? content_.asCollection.size() : 0;
   }
 
-  CollectionData& toArray() {
+  ArrayData& toArray() {
     setType(VALUE_IS_ARRAY);
-    new (&content_.asCollection) CollectionData();
-    return content_.asCollection;
+    new (&content_.asArray) ArrayData();
+    return content_.asArray;
   }
 
-  CollectionData& toArray(ResourceManager* resources) {
+  ArrayData& toArray(ResourceManager* resources) {
     release(resources);
     return toArray();
   }
@@ -594,8 +590,7 @@ inline size_t variantSize(const VariantData* var) {
   return var != 0 ? var->size() : 0;
 }
 
-inline CollectionData* variantToArray(VariantData* var,
-                                      ResourceManager* resources) {
+inline ArrayData* variantToArray(VariantData* var, ResourceManager* resources) {
   if (!var)
     return 0;
   return &var->toArray(resources);

src/ArduinoJson/Variant/Visitor.hpp

@@ -14,7 +14,7 @@ template <typename TResult>
 struct Visitor {
   typedef TResult result_type;
 
-  TResult visitArray(const CollectionData&) {
+  TResult visitArray(const ArrayData&) {
     return TResult();
   }