From 5790f3c8f728036c24999cd3c3639ddb1fed41b7 Mon Sep 17 00:00:00 2001
From: Benoit Blanchon <git@benoitblanchon.fr>
Date: Tue, 27 Jul 2021 12:06:44 +0200
Subject: [PATCH] Refactored string adapters: only one `IsString<T>` and
 `adaptString()`

---
 .devcontainer/devcontainer.json               |  3 +-
 extras/tests/Misc/StringAdapters.cpp          | 33 +++++++-------
 src/ArduinoJson/Collection/CollectionImpl.hpp |  4 +-
 src/ArduinoJson/Polyfills/type_traits.hpp     |  1 +
 .../Polyfills/type_traits/make_void.hpp       | 14 ++++++
 .../{ => Adapters}/ArduinoStringAdapter.hpp   | 20 ++++-----
 .../{ => Adapters}/ConstRamStringAdapter.hpp  | 19 ++++----
 .../{ => Adapters}/FlashStringAdapter.hpp     | 13 ++----
 .../Strings/Adapters/JsonStringAdapter.hpp    | 27 ++++++++++++
 .../Strings/Adapters/RamStringAdapter.hpp     | 29 +++++++++++++
 .../SizedFlashStringAdapter.hpp               | 11 ++---
 .../{ => Adapters}/SizedRamStringAdapter.hpp  | 12 ++----
 .../{ => Adapters}/StdStringAdapter.hpp       | 23 +++-------
 .../{ => Adapters}/StringViewAdapter.hpp      | 14 ++----
 src/ArduinoJson/Strings/IsString.hpp          | 18 --------
 src/ArduinoJson/Strings/RamStringAdapter.hpp  | 43 -------------------
 src/ArduinoJson/Strings/String.hpp            | 25 -----------
 src/ArduinoJson/Strings/StringAdapter.hpp     | 32 ++++++++++++++
 src/ArduinoJson/Strings/StringAdapters.hpp    | 17 ++++----
 src/ArduinoJson/Variant/VariantCompare.hpp    |  2 +-
 src/ArduinoJson/Variant/VariantData.hpp       |  5 ++-
 21 files changed, 176 insertions(+), 189 deletions(-)
 create mode 100644 src/ArduinoJson/Polyfills/type_traits/make_void.hpp
 rename src/ArduinoJson/Strings/{ => Adapters}/ArduinoStringAdapter.hpp (73%)
 rename src/ArduinoJson/Strings/{ => Adapters}/ConstRamStringAdapter.hpp (71%)
 rename src/ArduinoJson/Strings/{ => Adapters}/FlashStringAdapter.hpp (76%)
 create mode 100644 src/ArduinoJson/Strings/Adapters/JsonStringAdapter.hpp
 create mode 100644 src/ArduinoJson/Strings/Adapters/RamStringAdapter.hpp
 rename src/ArduinoJson/Strings/{ => Adapters}/SizedFlashStringAdapter.hpp (74%)
 rename src/ArduinoJson/Strings/{ => Adapters}/SizedRamStringAdapter.hpp (72%)
 rename src/ArduinoJson/Strings/{ => Adapters}/StdStringAdapter.hpp (60%)
 rename src/ArduinoJson/Strings/{ => Adapters}/StringViewAdapter.hpp (74%)
 delete mode 100644 src/ArduinoJson/Strings/IsString.hpp
 delete mode 100644 src/ArduinoJson/Strings/RamStringAdapter.hpp
 create mode 100644 src/ArduinoJson/Strings/StringAdapter.hpp

diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
index 309733b4..18e58b88 100644
--- a/.devcontainer/devcontainer.json
+++ b/.devcontainer/devcontainer.json
@@ -12,7 +12,8 @@
   // Add the IDs of extensions you want installed when the container is created.
   "extensions": [
 	"ms-vscode.cmake-tools",
-	"ms-vscode.cpptools"
+	"ms-vscode.cpptools",
+	"xaver.clang-format"
 ],
 
   // Use 'forwardPorts' to make a list of ports inside the container available locally.
diff --git a/extras/tests/Misc/StringAdapters.cpp b/extras/tests/Misc/StringAdapters.cpp
index 7a6f652f..2f523c97 100644
--- a/extras/tests/Misc/StringAdapters.cpp
+++ b/extras/tests/Misc/StringAdapters.cpp
@@ -2,23 +2,22 @@
 // Copyright Benoit Blanchon 2014-2021
 // MIT License
 
+#define ARDUINOJSON_ENABLE_PROGMEM 1
+#define ARDUINOJSON_ENABLE_ARDUINO_STRING 1
+
 #include "custom_string.hpp"
 #include "progmem_emulation.hpp"
 #include "weird_strcmp.hpp"
 
-#include <ArduinoJson/Strings/ArduinoStringAdapter.hpp>
-#include <ArduinoJson/Strings/ConstRamStringAdapter.hpp>
-#include <ArduinoJson/Strings/FlashStringAdapter.hpp>
-#include <ArduinoJson/Strings/SizedRamStringAdapter.hpp>
-#include <ArduinoJson/Strings/StdStringAdapter.hpp>
+#include <ArduinoJson/Strings/StringAdapters.hpp>
 
 #include <catch.hpp>
 
 using namespace ARDUINOJSON_NAMESPACE;
 
-TEST_CASE("ConstRamStringAdapter") {
+TEST_CASE("const char*") {
   SECTION("null") {
-    ConstRamStringAdapter adapter(NULL);
+    StringAdapter<const char*> adapter(NULL);
 
     CHECK(adapter.compare("bravo") < 0);
     CHECK(adapter.compare(NULL) == 0);
@@ -30,7 +29,7 @@ TEST_CASE("ConstRamStringAdapter") {
   }
 
   SECTION("non-null") {
-    ConstRamStringAdapter adapter("bravo");
+    StringAdapter<const char*> adapter("bravo");
 
     CHECK(adapter.compare(NULL) > 0);
     CHECK(adapter.compare("alpha") > 0);
@@ -44,9 +43,9 @@ TEST_CASE("ConstRamStringAdapter") {
   }
 }
 
-TEST_CASE("SizedRamStringAdapter") {
+TEST_CASE("const char* + size") {
   SECTION("null") {
-    SizedRamStringAdapter adapter(NULL, 10);
+    StringAdapter<const char*, true> adapter(NULL, 10);
 
     CHECK(adapter.compare("bravo") < 0);
     CHECK(adapter.compare(NULL) == 0);
@@ -58,7 +57,7 @@ TEST_CASE("SizedRamStringAdapter") {
   }
 
   SECTION("non-null") {
-    SizedRamStringAdapter adapter("bravo", 5);
+    StringAdapter<const char*, true> adapter("bravo", 5);
 
     CHECK(adapter.compare(NULL) > 0);
     CHECK(adapter.compare("alpha") > 0);
@@ -72,9 +71,9 @@ TEST_CASE("SizedRamStringAdapter") {
   }
 }
 
-TEST_CASE("FlashStringAdapter") {
+TEST_CASE("const __FlashStringHelper*") {
   SECTION("null") {
-    FlashStringAdapter adapter(NULL);
+    StringAdapter<const __FlashStringHelper*> adapter(NULL);
 
     CHECK(adapter.compare("bravo") < 0);
     CHECK(adapter.compare(NULL) == 0);
@@ -86,7 +85,7 @@ TEST_CASE("FlashStringAdapter") {
   }
 
   SECTION("non-null") {
-    FlashStringAdapter adapter = adaptString(F("bravo"));
+    StringAdapter<const __FlashStringHelper*> adapter = adaptString(F("bravo"));
 
     CHECK(adapter.compare(NULL) > 0);
     CHECK(adapter.compare("alpha") > 0);
@@ -102,7 +101,7 @@ TEST_CASE("FlashStringAdapter") {
 
 TEST_CASE("std::string") {
   std::string str("bravo");
-  StdStringAdapter<std::string> adapter = adaptString(str);
+  StringAdapter<std::string> adapter(str);
 
   CHECK(adapter.compare(NULL) > 0);
   CHECK(adapter.compare("alpha") > 0);
@@ -117,7 +116,7 @@ TEST_CASE("std::string") {
 
 TEST_CASE("Arduino String") {
   ::String str("bravo");
-  ArduinoStringAdapter adapter = adaptString(str);
+  StringAdapter< ::String> adapter(str);
 
   CHECK(adapter.compare(NULL) > 0);
   CHECK(adapter.compare("alpha") > 0);
@@ -132,7 +131,7 @@ TEST_CASE("Arduino String") {
 
 TEST_CASE("custom_string") {
   custom_string str("bravo");
-  StdStringAdapter<custom_string> adapter = adaptString(str);
+  StringAdapter<custom_string> adapter(str);
 
   CHECK(adapter.compare(NULL) > 0);
   CHECK(adapter.compare("alpha") > 0);
diff --git a/src/ArduinoJson/Collection/CollectionImpl.hpp b/src/ArduinoJson/Collection/CollectionImpl.hpp
index 49a24bee..18995bc1 100644
--- a/src/ArduinoJson/Collection/CollectionImpl.hpp
+++ b/src/ArduinoJson/Collection/CollectionImpl.hpp
@@ -62,9 +62,9 @@ inline bool CollectionData::copyFrom(const CollectionData& src,
     VariantData* var;
     if (s->key() != 0) {
       if (s->ownsKey())
-        var = addMember(RamStringAdapter(s->key()), pool);
+        var = addMember(adaptString(const_cast<char*>(s->key())), pool);
       else
-        var = addMember(ConstRamStringAdapter(s->key()), pool);
+        var = addMember(adaptString(s->key()), pool);
     } else {
       var = addElement(pool);
     }
diff --git a/src/ArduinoJson/Polyfills/type_traits.hpp b/src/ArduinoJson/Polyfills/type_traits.hpp
index 4a8ff4b9..24440b19 100644
--- a/src/ArduinoJson/Polyfills/type_traits.hpp
+++ b/src/ArduinoJson/Polyfills/type_traits.hpp
@@ -20,5 +20,6 @@
 #include "type_traits/is_signed.hpp"
 #include "type_traits/is_unsigned.hpp"
 #include "type_traits/make_unsigned.hpp"
+#include "type_traits/make_void.hpp"
 #include "type_traits/remove_const.hpp"
 #include "type_traits/remove_reference.hpp"
diff --git a/src/ArduinoJson/Polyfills/type_traits/make_void.hpp b/src/ArduinoJson/Polyfills/type_traits/make_void.hpp
new file mode 100644
index 00000000..cb2ebde5
--- /dev/null
+++ b/src/ArduinoJson/Polyfills/type_traits/make_void.hpp
@@ -0,0 +1,14 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright Benoit Blanchon 2014-2021
+// MIT License
+
+#pragma once
+
+namespace ARDUINOJSON_NAMESPACE {
+
+template <class = void>
+struct make_void {
+  typedef void type;
+};
+
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/ArduinoStringAdapter.hpp b/src/ArduinoJson/Strings/Adapters/ArduinoStringAdapter.hpp
similarity index 73%
rename from src/ArduinoJson/Strings/ArduinoStringAdapter.hpp
rename to src/ArduinoJson/Strings/Adapters/ArduinoStringAdapter.hpp
index 3797d686..c79958a3 100644
--- a/src/ArduinoJson/Strings/ArduinoStringAdapter.hpp
+++ b/src/ArduinoJson/Strings/Adapters/ArduinoStringAdapter.hpp
@@ -7,14 +7,15 @@
 #include <Arduino.h>
 
 #include <ArduinoJson/Polyfills/safe_strcmp.hpp>
-#include <ArduinoJson/Strings/IsString.hpp>
 #include <ArduinoJson/Strings/StoragePolicy.hpp>
+#include <ArduinoJson/Strings/StringAdapter.hpp>
 
 namespace ARDUINOJSON_NAMESPACE {
 
-class ArduinoStringAdapter {
+template <>
+class StringAdapter< ::String> {
  public:
-  ArduinoStringAdapter(const ::String& str) : _str(&str) {}
+  StringAdapter(const ::String& str) : _str(&str) {}
 
   void copyTo(char* p, size_t n) const {
     memcpy(p, _str->c_str(), n);
@@ -46,13 +47,10 @@ class ArduinoStringAdapter {
 };
 
 template <>
-struct IsString< ::String> : true_type {};
-
-template <>
-struct IsString< ::StringSumHelper> : true_type {};
-
-inline ArduinoStringAdapter adaptString(const ::String& str) {
-  return ArduinoStringAdapter(str);
-}
+class StringAdapter< ::StringSumHelper> : public StringAdapter< ::String> {
+ public:
+  StringAdapter< ::StringSumHelper>(const ::String& s)
+      : StringAdapter< ::String>(s) {}
+};
 
 }  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/ConstRamStringAdapter.hpp b/src/ArduinoJson/Strings/Adapters/ConstRamStringAdapter.hpp
similarity index 71%
rename from src/ArduinoJson/Strings/ConstRamStringAdapter.hpp
rename to src/ArduinoJson/Strings/Adapters/ConstRamStringAdapter.hpp
index 92298acf..70008ece 100644
--- a/src/ArduinoJson/Strings/ConstRamStringAdapter.hpp
+++ b/src/ArduinoJson/Strings/Adapters/ConstRamStringAdapter.hpp
@@ -8,14 +8,15 @@
 #include <string.h>  // strcmp
 
 #include <ArduinoJson/Polyfills/safe_strcmp.hpp>
-#include <ArduinoJson/Strings/IsString.hpp>
 #include <ArduinoJson/Strings/StoragePolicy.hpp>
+#include <ArduinoJson/Strings/StringAdapter.hpp>
 
 namespace ARDUINOJSON_NAMESPACE {
 
-class ConstRamStringAdapter {
+template <>
+class StringAdapter<const char*> {
  public:
-  ConstRamStringAdapter(const char* str = 0) : _str(str) {}
+  StringAdapter(const char* str = 0) : _str(str) {}
 
   int compare(const char* other) const {
     return safe_strcmp(_str, other);
@@ -45,14 +46,10 @@ class ConstRamStringAdapter {
   const char* _str;
 };
 
-template <>
-struct IsString<const char*> : true_type {};
-
 template <int N>
-struct IsString<const char[N]> : true_type {};
-
-inline ConstRamStringAdapter adaptString(const char* str) {
-  return ConstRamStringAdapter(str);
-}
+class StringAdapter<const char[N]> : public StringAdapter<const char*> {
+ public:
+  StringAdapter<const char[N]>(const char* s) : StringAdapter<const char*>(s) {}
+};
 
 }  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/FlashStringAdapter.hpp b/src/ArduinoJson/Strings/Adapters/FlashStringAdapter.hpp
similarity index 76%
rename from src/ArduinoJson/Strings/FlashStringAdapter.hpp
rename to src/ArduinoJson/Strings/Adapters/FlashStringAdapter.hpp
index 918a535c..3abcdf09 100644
--- a/src/ArduinoJson/Strings/FlashStringAdapter.hpp
+++ b/src/ArduinoJson/Strings/Adapters/FlashStringAdapter.hpp
@@ -5,14 +5,15 @@
 #pragma once
 
 #include <ArduinoJson/Polyfills/pgmspace.hpp>
-#include <ArduinoJson/Strings/IsString.hpp>
 #include <ArduinoJson/Strings/StoragePolicy.hpp>
+#include <ArduinoJson/Strings/StringAdapter.hpp>
 
 namespace ARDUINOJSON_NAMESPACE {
 
-class FlashStringAdapter {
+template <>
+class StringAdapter<const __FlashStringHelper*> {
  public:
-  FlashStringAdapter(const __FlashStringHelper* str) : _str(str) {}
+  StringAdapter(const __FlashStringHelper* str) : _str(str) {}
 
   int compare(const char* other) const {
     if (!other && !_str)
@@ -48,10 +49,4 @@ class FlashStringAdapter {
   const __FlashStringHelper* _str;
 };
 
-inline FlashStringAdapter adaptString(const __FlashStringHelper* str) {
-  return FlashStringAdapter(str);
-}
-
-template <>
-struct IsString<const __FlashStringHelper*> : true_type {};
 }  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/Adapters/JsonStringAdapter.hpp b/src/ArduinoJson/Strings/Adapters/JsonStringAdapter.hpp
new file mode 100644
index 00000000..c34abce5
--- /dev/null
+++ b/src/ArduinoJson/Strings/Adapters/JsonStringAdapter.hpp
@@ -0,0 +1,27 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright Benoit Blanchon 2014-2021
+// MIT License
+
+#pragma once
+
+#include <ArduinoJson/Strings/Adapters/RamStringAdapter.hpp>
+#include <ArduinoJson/Strings/String.hpp>
+
+namespace ARDUINOJSON_NAMESPACE {
+
+template <>
+class StringAdapter<String> : public StringAdapter<char*> {
+ public:
+  StringAdapter(const String& str)
+      : StringAdapter<char*>(str.c_str()), _isStatic(str.isStatic()) {}
+
+  bool isStatic() const {
+    return _isStatic;
+  }
+
+  typedef storage_policies::decide_at_runtime storage_policy;
+
+ private:
+  bool _isStatic;
+};
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/Adapters/RamStringAdapter.hpp b/src/ArduinoJson/Strings/Adapters/RamStringAdapter.hpp
new file mode 100644
index 00000000..f2b01d17
--- /dev/null
+++ b/src/ArduinoJson/Strings/Adapters/RamStringAdapter.hpp
@@ -0,0 +1,29 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright Benoit Blanchon 2014-2021
+// MIT License
+
+#pragma once
+
+#include <ArduinoJson/Polyfills/type_traits.hpp>
+#include <ArduinoJson/Strings/StoragePolicy.hpp>
+#include <ArduinoJson/Strings/StringAdapter.hpp>
+
+namespace ARDUINOJSON_NAMESPACE {
+
+template <typename TChar>
+class StringAdapter<TChar*, false,
+                    typename enable_if<sizeof(TChar) == 1 &&
+                                       !is_same<TChar, void>::value>::type>
+    : public StringAdapter<const char*> {
+ public:
+  StringAdapter(const TChar* str)
+      : StringAdapter<const char*>(reinterpret_cast<const char*>(str)) {}
+
+  void copyTo(char* p, size_t n) const {
+    memcpy(p, _str, n);
+  }
+
+  typedef ARDUINOJSON_NAMESPACE::storage_policies::store_by_copy storage_policy;
+};
+
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/SizedFlashStringAdapter.hpp b/src/ArduinoJson/Strings/Adapters/SizedFlashStringAdapter.hpp
similarity index 74%
rename from src/ArduinoJson/Strings/SizedFlashStringAdapter.hpp
rename to src/ArduinoJson/Strings/Adapters/SizedFlashStringAdapter.hpp
index 1055f666..098a7831 100644
--- a/src/ArduinoJson/Strings/SizedFlashStringAdapter.hpp
+++ b/src/ArduinoJson/Strings/Adapters/SizedFlashStringAdapter.hpp
@@ -5,14 +5,15 @@
 #pragma once
 
 #include <ArduinoJson/Namespace.hpp>
-#include <ArduinoJson/Strings/IsString.hpp>
 #include <ArduinoJson/Strings/StoragePolicy.hpp>
+#include <ArduinoJson/Strings/StringAdapter.hpp>
 
 namespace ARDUINOJSON_NAMESPACE {
 
-class SizedFlashStringAdapter {
+template <>
+class StringAdapter<const __FlashStringHelper*, true> {
  public:
-  SizedFlashStringAdapter(const __FlashStringHelper* str, size_t sz)
+  StringAdapter(const __FlashStringHelper* str, size_t sz)
       : _str(str), _size(sz) {}
 
   int compare(const char* other) const {
@@ -48,8 +49,4 @@ class SizedFlashStringAdapter {
   size_t _size;
 };
 
-inline SizedFlashStringAdapter adaptString(const __FlashStringHelper* str,
-                                           size_t sz) {
-  return SizedFlashStringAdapter(str, sz);
-}
 }  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/SizedRamStringAdapter.hpp b/src/ArduinoJson/Strings/Adapters/SizedRamStringAdapter.hpp
similarity index 72%
rename from src/ArduinoJson/Strings/SizedRamStringAdapter.hpp
rename to src/ArduinoJson/Strings/Adapters/SizedRamStringAdapter.hpp
index 62460a19..315e1f7f 100644
--- a/src/ArduinoJson/Strings/SizedRamStringAdapter.hpp
+++ b/src/ArduinoJson/Strings/Adapters/SizedRamStringAdapter.hpp
@@ -5,16 +5,17 @@
 #pragma once
 
 #include <ArduinoJson/Namespace.hpp>
-#include <ArduinoJson/Strings/IsString.hpp>
 #include <ArduinoJson/Strings/StoragePolicy.hpp>
+#include <ArduinoJson/Strings/StringAdapter.hpp>
 
 #include <string.h>  // strcmp
 
 namespace ARDUINOJSON_NAMESPACE {
 
-class SizedRamStringAdapter {
+template <typename TChar>
+class StringAdapter<TChar*, true> {
  public:
-  SizedRamStringAdapter(const char* str, size_t n) : _str(str), _size(n) {}
+  StringAdapter(const char* str, size_t n) : _str(str), _size(n) {}
 
   int compare(const char* other) const {
     return safe_strncmp(_str, other, _size);
@@ -43,9 +44,4 @@ class SizedRamStringAdapter {
   size_t _size;
 };
 
-template <typename TChar>
-inline SizedRamStringAdapter adaptString(const TChar* str, size_t size) {
-  return SizedRamStringAdapter(reinterpret_cast<const char*>(str), size);
-}
-
 }  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/StdStringAdapter.hpp b/src/ArduinoJson/Strings/Adapters/StdStringAdapter.hpp
similarity index 60%
rename from src/ArduinoJson/Strings/StdStringAdapter.hpp
rename to src/ArduinoJson/Strings/Adapters/StdStringAdapter.hpp
index 3979070e..382db893 100644
--- a/src/ArduinoJson/Strings/StdStringAdapter.hpp
+++ b/src/ArduinoJson/Strings/Adapters/StdStringAdapter.hpp
@@ -5,17 +5,19 @@
 #pragma once
 
 #include <ArduinoJson/Namespace.hpp>
-#include <ArduinoJson/Strings/IsString.hpp>
 #include <ArduinoJson/Strings/StoragePolicy.hpp>
+#include <ArduinoJson/Strings/StringAdapter.hpp>
 
 #include <string>
 
 namespace ARDUINOJSON_NAMESPACE {
 
-template <typename TString>
-class StdStringAdapter {
+template <typename TCharTraits, typename TAllocator>
+class StringAdapter<std::basic_string<char, TCharTraits, TAllocator> > {
  public:
-  StdStringAdapter(const TString& str) : _str(&str) {}
+  typedef std::basic_string<char, TCharTraits, TAllocator> string_type;
+
+  StringAdapter(const string_type& str) : _str(&str) {}
 
   void copyTo(char* p, size_t n) const {
     memcpy(p, _str->c_str(), n);
@@ -44,18 +46,7 @@ class StdStringAdapter {
   typedef storage_policies::store_by_copy storage_policy;
 
  private:
-  const TString* _str;
+  const string_type* _str;
 };
 
-template <typename TCharTraits, typename TAllocator>
-struct IsString<std::basic_string<char, TCharTraits, TAllocator> > : true_type {
-};
-
-template <typename TCharTraits, typename TAllocator>
-inline StdStringAdapter<std::basic_string<char, TCharTraits, TAllocator> >
-adaptString(const std::basic_string<char, TCharTraits, TAllocator>& str) {
-  return StdStringAdapter<std::basic_string<char, TCharTraits, TAllocator> >(
-      str);
-}
-
 }  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/StringViewAdapter.hpp b/src/ArduinoJson/Strings/Adapters/StringViewAdapter.hpp
similarity index 74%
rename from src/ArduinoJson/Strings/StringViewAdapter.hpp
rename to src/ArduinoJson/Strings/Adapters/StringViewAdapter.hpp
index 4720660b..4ddfce65 100644
--- a/src/ArduinoJson/Strings/StringViewAdapter.hpp
+++ b/src/ArduinoJson/Strings/Adapters/StringViewAdapter.hpp
@@ -5,16 +5,17 @@
 #pragma once
 
 #include <ArduinoJson/Namespace.hpp>
-#include <ArduinoJson/Strings/IsString.hpp>
 #include <ArduinoJson/Strings/StoragePolicy.hpp>
+#include <ArduinoJson/Strings/StringAdapter.hpp>
 
 #include <string_view>
 
 namespace ARDUINOJSON_NAMESPACE {
 
-class StringViewAdapter {
+template <>
+class StringAdapter<std::string_view> {
  public:
-  StringViewAdapter(std::string_view str) : _str(str) {}
+  StringAdapter(std::string_view str) : _str(str) {}
 
   void copyTo(char* p, size_t n) const {
     memcpy(p, _str.data(), n);
@@ -46,11 +47,4 @@ class StringViewAdapter {
   std::string_view _str;
 };
 
-template <>
-struct IsString<std::string_view> : true_type {};
-
-inline StringViewAdapter adaptString(const std::string_view& str) {
-  return StringViewAdapter(str);
-}
-
 }  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/IsString.hpp b/src/ArduinoJson/Strings/IsString.hpp
deleted file mode 100644
index af5a91a2..00000000
--- a/src/ArduinoJson/Strings/IsString.hpp
+++ /dev/null
@@ -1,18 +0,0 @@
-// ArduinoJson - https://arduinojson.org
-// Copyright Benoit Blanchon 2014-2021
-// MIT License
-
-#pragma once
-
-#include <ArduinoJson/Polyfills/type_traits.hpp>
-
-namespace ARDUINOJSON_NAMESPACE {
-template <typename>
-struct IsString : false_type {};
-
-template <typename T>
-struct IsString<const T> : IsString<T> {};
-
-template <typename T>
-struct IsString<T&> : IsString<T> {};
-}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/RamStringAdapter.hpp b/src/ArduinoJson/Strings/RamStringAdapter.hpp
deleted file mode 100644
index eded6c97..00000000
--- a/src/ArduinoJson/Strings/RamStringAdapter.hpp
+++ /dev/null
@@ -1,43 +0,0 @@
-// ArduinoJson - https://arduinojson.org
-// Copyright Benoit Blanchon 2014-2021
-// MIT License
-
-#pragma once
-
-#include <ArduinoJson/Strings/ConstRamStringAdapter.hpp>
-#include <ArduinoJson/Strings/IsString.hpp>
-#include <ArduinoJson/Strings/StoragePolicy.hpp>
-
-namespace ARDUINOJSON_NAMESPACE {
-
-class RamStringAdapter : public ConstRamStringAdapter {
- public:
-  RamStringAdapter(const char* str) : ConstRamStringAdapter(str) {}
-
-  void copyTo(char* p, size_t n) const {
-    memcpy(p, _str, n);
-  }
-
-  typedef ARDUINOJSON_NAMESPACE::storage_policies::store_by_copy storage_policy;
-};
-
-template <typename TChar>
-inline RamStringAdapter adaptString(const TChar* str) {
-  return RamStringAdapter(reinterpret_cast<const char*>(str));
-}
-
-inline RamStringAdapter adaptString(char* str) {
-  return RamStringAdapter(str);
-}
-
-template <typename TChar>
-struct IsString<TChar*> {
-  static const bool value = sizeof(TChar) == 1;
-};
-
-template <>
-struct IsString<void*> {
-  static const bool value = false;
-};
-
-}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/String.hpp b/src/ArduinoJson/Strings/String.hpp
index 4f2abdea..fff4077d 100644
--- a/src/ArduinoJson/Strings/String.hpp
+++ b/src/ArduinoJson/Strings/String.hpp
@@ -4,10 +4,6 @@
 
 #pragma once
 
-#include <ArduinoJson/Strings/ConstRamStringAdapter.hpp>
-#include <ArduinoJson/Strings/IsString.hpp>
-#include <ArduinoJson/Strings/StoragePolicy.hpp>
-
 namespace ARDUINOJSON_NAMESPACE {
 
 class String {
@@ -53,25 +49,4 @@ class String {
   bool _isStatic;
 };
 
-class StringAdapter : public RamStringAdapter {
- public:
-  StringAdapter(const String& str)
-      : RamStringAdapter(str.c_str()), _isStatic(str.isStatic()) {}
-
-  bool isStatic() const {
-    return _isStatic;
-  }
-
-  typedef storage_policies::decide_at_runtime storage_policy;
-
- private:
-  bool _isStatic;
-};
-
-template <>
-struct IsString<String> : true_type {};
-
-inline StringAdapter adaptString(const String& str) {
-  return StringAdapter(str);
-}
 }  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/StringAdapter.hpp b/src/ArduinoJson/Strings/StringAdapter.hpp
new file mode 100644
index 00000000..1d55b212
--- /dev/null
+++ b/src/ArduinoJson/Strings/StringAdapter.hpp
@@ -0,0 +1,32 @@
+// ArduinoJson - https://arduinojson.org
+// Copyright Benoit Blanchon 2014-2021
+// MIT License
+
+#pragma once
+
+#include <ArduinoJson/Polyfills/type_traits.hpp>
+
+namespace ARDUINOJSON_NAMESPACE {
+
+template <typename T, bool bounded = false, typename Enable = void>
+class StringAdapter;
+
+template <typename T>
+inline StringAdapter<T, false> adaptString(const T& str) {
+  return StringAdapter<T, false>(str);
+}
+
+template <typename T>
+inline StringAdapter<T, true> adaptString(const T& str, size_t sz) {
+  return StringAdapter<T, true>(str, sz);
+}
+
+template <typename T, typename Enable = void>
+struct IsString : false_type {};
+
+template <typename T>
+struct IsString<
+    T, typename make_void<typename StringAdapter<T>::storage_policy>::type>
+    : true_type {};
+
+}  // namespace ARDUINOJSON_NAMESPACE
diff --git a/src/ArduinoJson/Strings/StringAdapters.hpp b/src/ArduinoJson/Strings/StringAdapters.hpp
index 1de86bcd..ba763a67 100644
--- a/src/ArduinoJson/Strings/StringAdapters.hpp
+++ b/src/ArduinoJson/Strings/StringAdapters.hpp
@@ -4,23 +4,24 @@
 
 #pragma once
 
-#include <ArduinoJson/Strings/ConstRamStringAdapter.hpp>
-#include <ArduinoJson/Strings/RamStringAdapter.hpp>
-#include <ArduinoJson/Strings/SizedRamStringAdapter.hpp>
+#include <ArduinoJson/Strings/Adapters/ConstRamStringAdapter.hpp>
+#include <ArduinoJson/Strings/Adapters/JsonStringAdapter.hpp>
+#include <ArduinoJson/Strings/Adapters/RamStringAdapter.hpp>
+#include <ArduinoJson/Strings/Adapters/SizedRamStringAdapter.hpp>
 
 #if ARDUINOJSON_ENABLE_STD_STRING
-#  include <ArduinoJson/Strings/StdStringAdapter.hpp>
+#  include <ArduinoJson/Strings/Adapters/StdStringAdapter.hpp>
 #endif
 
 #if ARDUINOJSON_ENABLE_STRING_VIEW
-#  include <ArduinoJson/Strings/StringViewAdapter.hpp>
+#  include <ArduinoJson/Strings/Adapters/StringViewAdapter.hpp>
 #endif
 
 #if ARDUINOJSON_ENABLE_ARDUINO_STRING
-#  include <ArduinoJson/Strings/ArduinoStringAdapter.hpp>
+#  include <ArduinoJson/Strings/Adapters/ArduinoStringAdapter.hpp>
 #endif
 
 #if ARDUINOJSON_ENABLE_PROGMEM
-#  include <ArduinoJson/Strings/FlashStringAdapter.hpp>
-#  include <ArduinoJson/Strings/SizedFlashStringAdapter.hpp>
+#  include <ArduinoJson/Strings/Adapters/FlashStringAdapter.hpp>
+#  include <ArduinoJson/Strings/Adapters/SizedFlashStringAdapter.hpp>
 #endif
diff --git a/src/ArduinoJson/Variant/VariantCompare.hpp b/src/ArduinoJson/Variant/VariantCompare.hpp
index 025ef90a..4e0471a6 100644
--- a/src/ArduinoJson/Variant/VariantCompare.hpp
+++ b/src/ArduinoJson/Variant/VariantCompare.hpp
@@ -8,7 +8,7 @@
 #include <ArduinoJson/Misc/Visitable.hpp>
 #include <ArduinoJson/Numbers/arithmeticCompare.hpp>
 #include <ArduinoJson/Polyfills/type_traits.hpp>
-#include <ArduinoJson/Strings/IsString.hpp>
+#include <ArduinoJson/Strings/StringAdapter.hpp>
 #include <ArduinoJson/Variant/Visitor.hpp>
 
 namespace ARDUINOJSON_NAMESPACE {
diff --git a/src/ArduinoJson/Variant/VariantData.hpp b/src/ArduinoJson/Variant/VariantData.hpp
index fd54a94c..388b7e25 100644
--- a/src/ArduinoJson/Variant/VariantData.hpp
+++ b/src/ArduinoJson/Variant/VariantData.hpp
@@ -7,7 +7,7 @@
 #include <ArduinoJson/Memory/MemoryPool.hpp>
 #include <ArduinoJson/Misc/SerializedValue.hpp>
 #include <ArduinoJson/Numbers/convertNumber.hpp>
-#include <ArduinoJson/Strings/RamStringAdapter.hpp>
+#include <ArduinoJson/Strings/StringAdapters.hpp>
 #include <ArduinoJson/Variant/VariantContent.hpp>
 
 // VariantData can't have a constructor (to be a POD), so we have no way to fix
@@ -103,7 +103,8 @@ class VariantData {
       case VALUE_IS_OBJECT:
         return toObject().copyFrom(src._content.asCollection, pool);
       case VALUE_IS_OWNED_STRING:
-        return setString(RamStringAdapter(src._content.asString), pool);
+        return setString(adaptString(const_cast<char *>(src._content.asString)),
+                         pool);
       case VALUE_IS_OWNED_RAW:
         return setOwnedRaw(
             serialized(src._content.asRaw.data, src._content.asRaw.size), pool);