Issue 4127 - [emscripten] Convert subscription classes to C++ - Part 2

compiled/intrusive_ptr.h

 // Parts of this code have been copied from boost/smart_ptr/intrusive_ptr.hpp.
 //
 //  Copyright (c) 2001, 2002 Peter Dimov
 //
 // Distributed under the Boost Software License, Version 1.0. (See
 // accompanying file LICENSE_1_0.txt or copy at
 // http://www.boost.org/LICENSE_1_0.txt)
 
 #pragma once
 
@@ skipping 35 matching lines @@
 template<typename T,
     class = typename std::enable_if<std::is_base_of<ref_counted,T>::value>::type>
 class intrusive_ptr
 {
 public:
   explicit intrusive_ptr()
       : mPointer(nullptr)
   {
   }
 
-  explicit intrusive_ptr(T* pointer)
+  explicit intrusive_ptr(T* pointer, bool addRef = true)
       : mPointer(pointer)
   {
-    // Raw pointers always had their reference count increased by whatever gave
-    // us the pointer so we don't need to do it here.

[Wladimir Palant, 2017/03/16 18:31:23]

This comment turned out to be wrong and the previous behavior quite a footgun,
so now addref can be suppressed explicitly when necessary.

+    if (mPointer && addRef)
+      mPointer->AddRef();
   }
 
   explicit intrusive_ptr(const intrusive_ptr& other)
       : mPointer(other.mPointer)
   {
     if (mPointer)
       mPointer->AddRef();
   }
 
   explicit intrusive_ptr(intrusive_ptr&& other)
@@ skipping 120 matching lines @@
 inline bool operator==(const T* a, const intrusive_ptr<U>& b)
 {
   return a == b.get();
 }
 
 template<typename T, typename U>
 inline bool operator!=(const T* a, intrusive_ptr<U> const& b)
 {
   return a != b.get();
 }