Added a return value to visitors

src/ArduinoJson/Array/ArrayFunctions.hpp

@@ -12,12 +12,13 @@ inline VariantData *arrayAdd(CollectionData *arr, MemoryPool *pool) {
   return arr ? arr->addElement(pool) : 0;
 }
 
-template <typename Visitor>
-inline void arrayAccept(const CollectionData *arr, Visitor &visitor) {
+template <typename TVisitor>
+inline typename TVisitor::result_type arrayAccept(const CollectionData *arr,
+                                                  TVisitor &visitor) {
   if (arr)
-    visitor.visitArray(*arr);
+    return visitor.visitArray(*arr);
   else
-    visitor.visitNull();
+    return visitor.visitNull();
 }
 
 inline bool arrayEquals(const CollectionData *lhs, const CollectionData *rhs) {

src/ArduinoJson/Array/ArrayRef.hpp

@@ -27,9 +27,9 @@ class ArrayRefBase {
     return VariantConstRef(reinterpret_cast<const VariantData*>(data));
   }
 
-  template <typename Visitor>
-  FORCE_INLINE void accept(Visitor& visitor) const {
-    arrayAccept(_data, visitor);
+  template <typename TVisitor>
+  FORCE_INLINE typename TVisitor::result_type accept(TVisitor& visitor) const {
+    return arrayAccept(_data, visitor);
   }
 
   FORCE_INLINE bool isNull() const {

src/ArduinoJson/Array/ElementProxy.hpp

@@ -98,8 +98,8 @@ class ElementProxy : public VariantOperators<ElementProxy<TArray> >,
     return getOrAddUpstreamElement().set(value);
   }
 
-  template <typename Visitor>
-  void accept(Visitor& visitor) const {
+  template <typename TVisitor>
+  typename TVisitor::result_type accept(TVisitor& visitor) const {
     return getUpstreamElement().accept(visitor);
   }
 

src/ArduinoJson/Array/Utilities.hpp

@@ -65,40 +65,61 @@ inline bool copyArray(T (&src)[N1][N2], JsonDocument& dst) {
 }
 
 template <typename T>
-class ArrayCopier1D {
+class ArrayCopier1D : public Visitor<size_t> {
  public:
   ArrayCopier1D(T* destination, size_t capacity)
-      : _destination(destination), _capacity(capacity), _size(0) {}
+      : _destination(destination), _capacity(capacity) {}
 
-  void visitArray(const CollectionData& array) {
+  size_t visitArray(const CollectionData& array) {
+    size_t size = 0;
     VariantSlot* slot = array.head();
 
-    while (slot != 0 && _size < _capacity) {
-      _destination[_size++] = variantAs<T>(slot->data());
+    while (slot != 0 && size < _capacity) {
+      _destination[size++] = variantAs<T>(slot->data());
       slot = slot->next();
     }
+    return size;
   }
-  void visitObject(const CollectionData&) {}
-  void visitFloat(Float) {}
-  void visitString(const char*) {}
-  void visitRawJson(const char*, size_t) {}
-  void visitNegativeInteger(UInt) {}
-  void visitPositiveInteger(UInt) {}
-  void visitBoolean(bool) {}
-  void visitNull() {}
 
-  size_t result() const {
-    return _size;
+  size_t visitObject(const CollectionData&) {
+    return 0;
+  }
+
+  size_t visitFloat(Float) {
+    return 0;
+  }
+
+  size_t visitString(const char*) {
+    return 0;
+  }
+
+  size_t visitRawJson(const char*, size_t) {
+    return 0;
+  }
+
+  size_t visitNegativeInteger(UInt) {
+    return 0;
+  }
+
+  size_t visitPositiveInteger(UInt) {
+    return 0;
+  }
+
+  size_t visitBoolean(bool) {
+    return 0;
+  }
+
+  size_t visitNull() {
+    return 0;
   }
 
  private:
   T* _destination;
   size_t _capacity;
-  size_t _size;
 };
 
 template <typename T, size_t N1, size_t N2>
-class ArrayCopier2D {
+class ArrayCopier2D : public Visitor<void> {
  public:
   ArrayCopier2D(T (*destination)[N1][N2]) : _destination(destination) {}
 
@@ -136,8 +157,8 @@ inline typename enable_if<!is_array<T>::value, size_t>::type copyArray(
 template <typename TSource, typename T>
 inline size_t copyArray(const TSource& src, T* dst, size_t len) {
   ArrayCopier1D<T> copier(dst, len);
-  src.accept(copier);
-  return copier.result();
+
+  return src.accept(copier);
 }
 
 // Copy a JsonArray to a 2D array