Extract toArray()

Before: 9894, 8796, 9708, 12674, 9970
After:  9884, 8796, 9702, 12668, 9964
Target: 9800, 8458, 9634, 12290, 9702

Author: bblanchon

src/ArduinoJson/Json/JsonDeserializer.hpp

@@ -71,7 +71,7 @@ class JsonDeserializer {
     switch (current()) {
       case '[':
         if (filter.allowArray())
-          return parseArray(VariantImpl(variant, resources_).toArray(), filter,
+          return parseArray(VariantImpl::toArray(variant, resources_), filter,
                             nestingLimit);
         else
           return skipArray(nestingLimit);

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 = VariantImpl::toArray(variant, resources_);
     }
 
     TFilter elementFilter = filter[0U];

src/ArduinoJson/Variant/VariantData.hpp

@@ -478,9 +478,15 @@ class VariantImpl {
   }
 
   ArrayImpl toArray() {
-    ARDUINOJSON_ASSERT(type() == VariantType::Null);  // must call clear() first
     if (!data_)
       return ArrayImpl();
+    return toArray(data_, resources_);
+  }
+
+  static ArrayImpl toArray(VariantData* data_, ResourceManager* resources_) {
+    ARDUINOJSON_ASSERT(data_ != nullptr);
+    ARDUINOJSON_ASSERT(data_->type == VariantType::Null);
+    ARDUINOJSON_ASSERT(resources_ != nullptr);
     data_->type = VariantType::Array;
     return ArrayImpl(new (&data_->content.asCollection) CollectionData(),
                      resources_);