Issue 6526 - Use Maybe<> version of soon to be deprecated API in v8 6.7

src/Utils.h

Index: src/Utils.h
===================================================================
--- a/src/Utils.h
+++ b/src/Utils.h
@@ -33,17 +33,17 @@
 {
   namespace Utils
   {
     void CheckTryCatch(v8::Isolate* isolate, const v8::TryCatch& tryCatch);
 
     /*
      * Check for exception and then that a MaybeLocal<> isn't empty,
      * and throw a JsError if it is, otherwise return the Local<>
-     * Call using the macro %CHECKED_MAYBE to get the location.
+     * Call using the macro %CHECKED_TO_LOCAL to get the location.
      */
     template<class T>
     v8::Local<T> CheckedToLocal(v8::Isolate* isolate,
       v8::MaybeLocal<T>&& value, const v8::TryCatch* tryCatch,
       const char* filename, int line)
     {
       if (tryCatch)
         CheckTryCatch(isolate, *tryCatch);
@@ -53,16 +53,32 @@
     }
 
 #define CHECKED_TO_LOCAL(isolate, value, tryCatch)                      \
     AdblockPlus::Utils::CheckedToLocal(isolate, value, &tryCatch, __FILE__, __LINE__)
 
 #define CHECKED_TO_LOCAL_NOTHROW(isolate, value) \
     AdblockPlus::Utils::CheckedToLocal(isolate, value, nullptr, __FILE__, __LINE__)
 
+    /*
+     * Check that a Maybe<> isn't empty,
+     * and throw a JsError if it is, otherwise return the value
+     * Call using the macro %CHECKED_TO_VALUE to get the location.
+     */
+    template<class T>
+    T CheckedToValue(v8::Maybe<T>&& value, const char* filename, int line)
+    {
+      if (value.IsNothing())
+        throw AdblockPlus::JsError("Empty value at ", filename, line);
+      return value.FromJust();
+    }
+
+#define CHECKED_TO_VALUE(value) \
+    AdblockPlus::Utils::CheckedToValue(value, __FILE__, __LINE__)
+
     std::string FromV8String(v8::Isolate* isolate, const v8::Local<v8::Value>& value);
     StringBuffer StringBufferFromV8String(v8::Isolate* isolate, const v8::Local<v8::Value>& value);
     v8::MaybeLocal<v8::String> ToV8String(v8::Isolate* isolate, const std::string& str);
     v8::MaybeLocal<v8::String> StringBufferToV8String(v8::Isolate* isolate, const StringBuffer& bytes);
     void ThrowExceptionInJS(v8::Isolate* isolate, const std::string& str);
 
     // Code for templated function has to be in a header file, can't be in .cpp
     template<class T>