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

src/JsEngine.cpp

Index: src/JsEngine.cpp
===================================================================
--- a/src/JsEngine.cpp
+++ b/src/JsEngine.cpp
@@ -20,36 +20,55 @@
 #include "JsContext.h"
 #include "JsError.h"
 #include "Utils.h"
 #include <libplatform/libplatform.h>
 #include <AdblockPlus/Platform.h>
 
 namespace
 {
-  v8::Local<v8::Script> CompileScript(v8::Isolate* isolate,
+  v8::MaybeLocal<v8::Script> CompileScript(v8::Isolate* isolate,
     const std::string& source, const std::string& filename)
   {
     using AdblockPlus::Utils::ToV8String;
     const v8::Local<v8::String> v8Source = ToV8String(isolate, source);
     if (filename.length())
     {
       const v8::Local<v8::String> v8Filename = ToV8String(isolate, filename);
-      return v8::Script::Compile(v8Source, v8Filename);
+      v8::ScriptOrigin scriptOrigin(v8Filename);
+      return v8::Script::Compile(isolate->GetCurrentContext(), v8Source, &scriptOrigin);
     }
     else
-      return v8::Script::Compile(v8Source);
+      return v8::Script::Compile(isolate->GetCurrentContext(), v8Source);
   }
 
   void CheckTryCatch(v8::Isolate* isolate, const v8::TryCatch& tryCatch)
   {
     if (tryCatch.HasCaught())
       throw AdblockPlus::JsError(isolate, tryCatch.Exception(), tryCatch.Message());
   }
 
+  /*
+   * 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) \
+  CheckedToLocal(isolate, value, tryCatch, __FILE__, __LINE__)
+
   class V8Initializer
   {
     V8Initializer()
       : platform{nullptr}
     {
       std::string cmd = "--use_strict";
       v8::V8::SetFlagsFromString(cmd.c_str(), cmd.length());
       platform = v8::platform::CreateDefaultPlatform();
@@ -187,22 +206,20 @@
 }
 
 AdblockPlus::JsValue AdblockPlus::JsEngine::Evaluate(const std::string& source,
     const std::string& filename)
 {
   const JsContext context(*this);
   auto isolate = GetIsolate();
   const v8::TryCatch tryCatch(isolate);
-  const v8::Local<v8::Script> script = CompileScript(isolate, source,
-    filename);
-  CheckTryCatch(isolate, tryCatch);
-  v8::Local<v8::Value> result = script->Run();
-  CheckTryCatch(isolate, tryCatch);
-  return JsValue(shared_from_this(), result);
+  v8::MaybeLocal<v8::Script> script = CompileScript(isolate, source, filename);
+  v8::MaybeLocal<v8::Value> result = CHECKED_TO_LOCAL(
+    isolate, script, tryCatch)->Run(isolate->GetCurrentContext());
+  return JsValue(shared_from_this(), CHECKED_TO_LOCAL(isolate, result, tryCatch));
 }
 
 void AdblockPlus::JsEngine::SetEventCallback(const std::string& eventName,
     const AdblockPlus::JsEngine::EventCallback& callback)
 {
   if (!callback)
   {
     RemoveEventCallback(eventName);