Issue #3594 - Remove `globalJsObject` and add `GetGlobalObject()`

src/JsEngine.cpp

Index: src/JsEngine.cpp
===================================================================
--- a/src/JsEngine.cpp
+++ b/src/JsEngine.cpp
@@ -91,13 +91,19 @@
 
   result->context.reset(new v8::Persistent<v8::Context>(result->GetIsolate(),
     v8::Context::New(result->GetIsolate())));
-  v8::Local<v8::Object> globalContext = v8::Local<v8::Context>::New(
-    result->GetIsolate(), *result->context)->Global();
-  result->globalJsObject = JsValuePtr(new JsValue(result, globalContext));
-  AdblockPlus::GlobalJsObject::Setup(result, appInfo, result->globalJsObject);
+  AdblockPlus::GlobalJsObject::Setup(result, appInfo, result->GetGlobalObject());
   return result;
 }
 
+AdblockPlus::JsValuePtr AdblockPlus::JsEngine::GetGlobalObject()
+{
+  const auto i = GetIsolate();

[sergei, 2016/11/28 15:04:33]

Why not to use JsContext context(shared_from_this());?

[Eric, 2016/11/28 15:33:24]

That should work. The code here is a minimal extraction refactoring from the
existing code, which meant that I just copied the existing statements over. I'll
see if this works. If it works here, it's probably also the right thing to do in
New() as well, where I copied it from.

One of the things I've wondered looking at this code the last couple of days is
why there's a separate context class at all. Evidently others are using
`v8::Persistent` to hold a single context, which would get rid of a bunch of
overhead creating it each time it's needed.

+  const v8::Locker locker(i);
+  const v8::Isolate::Scope isolateScope(i);
+  const v8::HandleScope handleScope(i);
+  return JsValuePtr(new JsValue(shared_from_this(), v8::Local<v8::Context>::New(i, *context)->Global()));
+};
+
 AdblockPlus::JsValuePtr AdblockPlus::JsEngine::Evaluate(const std::string& source,
     const std::string& filename)
 {
@@ -244,8 +250,8 @@
 void AdblockPlus::JsEngine::SetGlobalProperty(const std::string& name, 
                                               AdblockPlus::JsValuePtr value)
 {
-  if (!globalJsObject)
+  auto global = GetGlobalObject();
+  if (!global)
     throw std::runtime_error("Global object cannot be null");
-
-  globalJsObject->SetProperty(name, value);
+  global->SetProperty(name, value);
 }