[unreal]v8 和 UE 字符串传递默认使用 UTF16 避免编码转换 (#1628)

* v8 <-> UE use UTF16-LE by default

* clang-format  remove empty space

* quick js doesn't have native utf16 support

* 实现不能放到Public 头文件 V8Utils.h里

* export symbols because FV8Utils is no more header only

unreal/Puerts/Source/JsEnv/Private/V8Utils.cpp

@@ -0,0 +1,19 @@
+#include <V8Utils.h>
+
+v8::Local<v8::String> puerts::FV8Utils::ToV8String(v8::Isolate* Isolate, const TCHAR* String)
+{
+#if WITH_QUICKJS
+    return v8::String::NewFromUtf8(Isolate, TCHAR_TO_UTF8(String), v8::NewStringType::kNormal).ToLocalChecked();
+#else
+    return v8::String::NewFromTwoByte(Isolate, TCHAR_TO_UTF16(String), v8::NewStringType::kNormal).ToLocalChecked();
+#endif
+}
+
+FString puerts::FV8Utils::ToFString(v8::Isolate* Isolate, v8::Local<v8::Value> Value)
+{
+#if WITH_QUICKJS
+    return UTF8_TO_TCHAR(*(v8::String::Utf8Value(Isolate, Value)));
+#else
+    return UTF16_TO_TCHAR(*(v8::String::Value(Isolate, Value)));
+#endif
+}

unreal/Puerts/Source/JsEnv/Public/V8Utils.h

@@ -34,7 +34,7 @@ enum ArgType
     EArgObject
 };
 
-class FV8Utils
+class JSENV_API FV8Utils
 {
 public:
     FORCEINLINE static void ThrowException(v8::Isolate* Isolate, const FString& Message)
@@ -96,18 +96,15 @@ class FV8Utils
 
     FORCEINLINE static v8::Local<v8::String> InternalString(v8::Isolate* Isolate, const FString& String)
     {
-        return v8::String::NewFromUtf8(Isolate, TCHAR_TO_UTF8(*String), v8::NewStringType::kNormal).ToLocalChecked();
+        return ToV8String(Isolate, String);
     }
 
     FORCEINLINE static v8::Local<v8::String> InternalString(v8::Isolate* Isolate, const char* String)
     {
         return v8::String::NewFromUtf8(Isolate, String, v8::NewStringType::kNormal).ToLocalChecked();
     }
 
-    FORCEINLINE static FString ToFString(v8::Isolate* Isolate, v8::Local<v8::Value> Value)
-    {
-        return UTF8_TO_TCHAR(*(v8::String::Utf8Value(Isolate, Value)));
-    }
+    static FString ToFString(v8::Isolate* Isolate, v8::Local<v8::Value> Value);
 
     FORCEINLINE static FName ToFName(v8::Isolate* Isolate, v8::Local<v8::Value> Value)
     {
@@ -146,10 +143,7 @@ class FV8Utils
         return ToV8String(Isolate, String.ToString());
     }
 
-    FORCEINLINE static v8::Local<v8::String> ToV8String(v8::Isolate* Isolate, const TCHAR* String)
-    {
-        return v8::String::NewFromUtf8(Isolate, TCHAR_TO_UTF8(String), v8::NewStringType::kNormal).ToLocalChecked();
-    }
+    static v8::Local<v8::String> ToV8String(v8::Isolate* Isolate, const TCHAR* String);
 
     FORCEINLINE static v8::Local<v8::String> ToV8String(v8::Isolate* Isolate, const char* String)
     {