Implement nesting() out of VariantData

src/ArduinoJson/Array/ArrayRef.hpp

@@ -23,8 +23,7 @@ template <typename TData>
 class ArrayRefBase {
  public:
   operator VariantConstRef() const {
-    const void* data = _data;  // prevent warning cast-align
-    return VariantConstRef(reinterpret_cast<const VariantData*>(data));
+    return VariantConstRef(getVariantData());
   }
 
   template <typename TVisitor>
@@ -45,7 +44,7 @@ class ArrayRefBase {
   }
 
   FORCE_INLINE size_t nesting() const {
-    return _data ? _data->nesting() : 0;
+    return variantNesting(getVariantData());
   }
 
   FORCE_INLINE size_t size() const {
@@ -53,6 +52,11 @@ class ArrayRefBase {
   }
 
  protected:
+  const VariantData* getVariantData() const {
+    const void* data = _data;  // prevent warning cast-align
+    return reinterpret_cast<const VariantData*>(data);
+  }
+
   ArrayRefBase(TData* data) : _data(data) {}
   TData* _data;
 };

src/ArduinoJson/Collection/CollectionData.hpp

@@ -64,7 +64,6 @@ class CollectionData {
 
   void clear();
   size_t memoryUsage() const;
-  size_t nesting() const;
   size_t size() const;
 
   VariantSlot *addSlot(MemoryPool *);

src/ArduinoJson/Collection/CollectionImpl.hpp

@@ -203,16 +203,6 @@ inline size_t CollectionData::memoryUsage() const {
   return total;
 }
 
-inline size_t CollectionData::nesting() const {
-  size_t maxChildNesting = 0;
-  for (VariantSlot* s = _head; s; s = s->next()) {
-    size_t childNesting = s->data()->nesting();
-    if (childNesting > maxChildNesting)
-      maxChildNesting = childNesting;
-  }
-  return maxChildNesting + 1;
-}
-
 inline size_t CollectionData::size() const {
   return slotSize(_head);
 }

src/ArduinoJson/Document/JsonDocument.hpp

@@ -60,7 +60,7 @@ class JsonDocument : public Visitable,
   }
 
   size_t nesting() const {
-    return _data.nesting();
+    return variantNesting(&_data);
   }
 
   size_t capacity() const {

src/ArduinoJson/Object/ObjectRef.hpp

@@ -18,8 +18,7 @@ template <typename TData>
 class ObjectRefBase {
  public:
   operator VariantConstRef() const {
-    const void* data = _data;  // prevent warning cast-align
-    return VariantConstRef(reinterpret_cast<const VariantData*>(data));
+    return VariantConstRef(getVariantData());
   }
 
   template <typename TVisitor>
@@ -40,7 +39,7 @@ class ObjectRefBase {
   }
 
   FORCE_INLINE size_t nesting() const {
-    return _data ? _data->nesting() : 0;
+    return variantNesting(getVariantData());
   }
 
   FORCE_INLINE size_t size() const {
@@ -48,6 +47,11 @@ class ObjectRefBase {
   }
 
  protected:
+  const VariantData* getVariantData() const {
+    const void* data = _data;  // prevent warning cast-align
+    return reinterpret_cast<const VariantData*>(data);
+  }
+
   ObjectRefBase(TData* data) : _data(data) {}
   TData* _data;
 };

src/ArduinoJson/Variant/VariantData.hpp

@@ -91,6 +91,10 @@ class VariantData {
     return const_cast<VariantData *>(this)->asArray();
   }
 
+  const CollectionData *asCollection() const {
+    return isCollection() ? &_content.asCollection : 0;
+  }
+
   CollectionData *asObject() {
     return isObject() ? &_content.asCollection : 0;
   }
@@ -245,10 +249,6 @@ class VariantData {
     }
   }
 
-  size_t nesting() const {
-    return isCollection() ? _content.asCollection.nesting() : 0;
-  }
-
   size_t size() const {
     return isCollection() ? _content.asCollection.size() : 0;
   }

src/ArduinoJson/Variant/VariantFunctions.hpp

@@ -7,6 +7,7 @@
 #include <ArduinoJson/Polyfills/attributes.hpp>
 #include <ArduinoJson/Strings/StoragePolicy.hpp>
 #include <ArduinoJson/Variant/VariantData.hpp>
+#include <ArduinoJson/Variant/Visitor.hpp>
 
 namespace ARDUINOJSON_NAMESPACE {
 
@@ -106,4 +107,21 @@ inline bool variantIsNull(const VariantData *var) {
   return var == 0 || var->isNull();
 }
 
+inline size_t variantNesting(const VariantData *var) {
+  if (!var)
+    return 0;
+
+  const CollectionData *collection = var->asCollection();
+  if (!collection)
+    return 0;
+
+  size_t maxChildNesting = 0;
+  for (const VariantSlot *s = collection->head(); s; s = s->next()) {
+    size_t childNesting = variantNesting(s->data());
+    if (childNesting > maxChildNesting)
+      maxChildNesting = childNesting;
+  }
+  return maxChildNesting + 1;
+}
+
 }  // namespace ARDUINOJSON_NAMESPACE

src/ArduinoJson/Variant/VariantRef.hpp

@@ -41,7 +41,7 @@ class VariantRefBase : public VariantTag {
   }
 
   FORCE_INLINE size_t nesting() const {
-    return _data ? _data->nesting() : 0;
+    return variantNesting(_data);
   }
 
   size_t size() const {