Issue 6526 - Use the maybe version of Compile() and Run()

src/Utils.h

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-present eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #ifndef ADBLOCK_PLUS_UTILS_H
 #define ADBLOCK_PLUS_UTILS_H
 
 #include <algorithm>
 #include <cctype>
 #include <functional>
 #include <string>
 #include <vector>
 #include <v8.h>
 
 #include "AdblockPlus/JsValue.h"
 
+#include "JsError.h"
+
 namespace AdblockPlus
 {
   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.
+     */
+    template<class T>
+    v8::Local<T> CheckedToLocal(v8::Isolate* isolate,
+      v8::MaybeLocal<T>& value, const v8::TryCatch& tryCatch,
+      const char* filename, int line)
+    {
+      CheckTryCatch(isolate, tryCatch);
+      if (value.IsEmpty())
+        throw AdblockPlus::JsError("Empty value at ", filename, line);
+      return value.ToLocalChecked();
+    }
+
+#define CHECKED_TO_LOCAL(isolate, value, tryCatch)                      \
+    AdblockPlus::Utils::CheckedToLocal(isolate, value, tryCatch, __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::Local<v8::String> ToV8String(v8::Isolate* isolate, const std::string& str);
     v8::Local<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>
     T TrimString(const T& text)
     {
       // Via http://stackoverflow.com/questions/216823/whats-the-best-way-to-trim-stdstring
       T trimmed(text);
       trimmed.erase(trimmed.begin(), std::find_if(trimmed.begin(), trimmed.end(), std::not1(std::ptr_fun<int, int>(std::isspace))));
       trimmed.erase(std::find_if(trimmed.rbegin(), trimmed.rend(), std::not1(std::ptr_fun<int, int>(std::isspace))).base(), trimmed.end());
       return trimmed;
     }
 #ifdef _WIN32
     std::wstring ToUtf16String(const std::string& str);
     std::string ToUtf8String(const std::wstring& str);
     std::wstring CanonizeUrl(const std::wstring& url);
 #endif
   }
 }
 
 #endif