Rewrite all converters

Before: 9802, 8486, 9630, 12418, 9654
After:  9802, 8446, 9630, 12242, 9660
Target: 9800, 8458, 9634, 12290, 9702

Author: bblanchon

src/ArduinoJson/Variant/ConverterImpl.hpp

@@ -60,9 +60,12 @@ struct Converter<T, detail::enable_if_t<detail::is_integral<T>::value &&
     : private detail::VariantAttorney {
   static bool toJson(T src, JsonVariant dst) {
     ARDUINOJSON_ASSERT_INTEGER_TYPE_IS_SUPPORTED(T);
-    auto variant = getVariantImpl(dst);
-    variant.clear();
-    return variant.setInteger(src);
+    auto data = getData(dst);
+    auto resources = getResourceManager(dst);
+    if (!data)
+      return false;
+    detail::VariantImpl::clear(data, resources);
+    return detail::VariantImpl::setInteger(src, data, resources);
   }
 
   static T fromJson(JsonVariantConst src) {
@@ -94,9 +97,13 @@ struct Converter<T, detail::enable_if_t<detail::is_enum<T>::value>>
 template <>
 struct Converter<bool> : private detail::VariantAttorney {
   static bool toJson(bool src, JsonVariant dst) {
-    auto variant = getVariantImpl(dst);
-    variant.clear();
-    return variant.setBoolean(src);
+    auto data = getData(dst);
+    auto resources = getResourceManager(dst);
+    if (!data)
+      return false;
+    detail::VariantImpl::clear(data, resources);
+    data->setBoolean(src);
+    return true;
   }
 
   static bool fromJson(JsonVariantConst src) {
@@ -134,9 +141,12 @@ struct Converter<T, detail::enable_if_t<detail::is_floating_point<T>::value>>
 template <>
 struct Converter<const char*> : private detail::VariantAttorney {
   static void toJson(const char* src, JsonVariant dst) {
-    auto variant = getVariantImpl(dst);
-    variant.clear();
-    variant.setString(detail::adaptString(src));
+    auto data = getData(dst);
+    auto resources = getResourceManager(dst);
+    if (!data)
+      return;
+    detail::VariantImpl::clear(data, resources);
+    detail::VariantImpl::setString(detail::adaptString(src), data, resources);
   }
 
   static const char* fromJson(JsonVariantConst src) {
@@ -151,10 +161,14 @@ struct Converter<const char*> : private detail::VariantAttorney {
 
 template <>
 struct Converter<JsonString> : private detail::VariantAttorney {
-  static void toJson(JsonString src, JsonVariant dst) {
-    auto variant = getVariantImpl(dst);
-    variant.clear();
-    variant.setString(detail::adaptString(src));
+  static bool toJson(JsonString src, JsonVariant dst) {
+    auto data = getData(dst);
+    auto resources = getResourceManager(dst);
+    if (!data)
+      return false;
+    detail::VariantImpl::clear(data, resources);
+    return detail::VariantImpl::setString(detail::adaptString(src), data,
+                                          resources);
   }
 
   static JsonString fromJson(JsonVariantConst src) {
@@ -168,11 +182,15 @@ struct Converter<JsonString> : private detail::VariantAttorney {
 };
 
 template <typename T>
-inline detail::enable_if_t<detail::IsString<T>::value> convertToJson(
+inline detail::enable_if_t<detail::IsString<T>::value, bool> convertToJson(
     const T& src, JsonVariant dst) {
-  auto variant = detail::VariantAttorney::getVariantImpl(dst);
-  variant.clear();
-  variant.setString(detail::adaptString(src));
+  auto data = detail::VariantAttorney::getData(dst);
+  auto resources = detail::VariantAttorney::getResourceManager(dst);
+  if (!data)
+    return false;
+  detail::VariantImpl::clear(data, resources);
+  return detail::VariantImpl::setString(detail::adaptString(src), data,
+                                        resources);
 }
 
 // SerializedValue<std::string>
@@ -190,7 +208,10 @@ struct Converter<SerializedValue<T>> : private detail::VariantAttorney {
 template <>
 struct Converter<detail::nullptr_t> : private detail::VariantAttorney {
   static void toJson(detail::nullptr_t, JsonVariant dst) {
-    getVariantImpl(dst).clear();
+    auto data = getData(dst);
+    auto resources = getResourceManager(dst);
+    if (data)
+      detail::VariantImpl::clear(data, resources);
   }
   static detail::nullptr_t fromJson(JsonVariantConst) {
     return nullptr;