From 76699e582851220545b90edfe2d4dfa4b6f3e152 Mon Sep 17 00:00:00 2001
From: Andrey Semashev <andrey.semashev@gmail.com>
Date: Sun, 28 Oct 2018 00:37:42 +0300
Subject: [PATCH] Use Boost.TypeIndex CTTI to implement type info when RTTI is
 not enabled.

This allows to solve the problem with comparing addresses of global id_provider
objects, which fail if the objects reside in different modules. Boost.TypeIndex
solves this problem by comparing specially crafted strings, which are equal
if the respective types are the same.

Unfortunately, this will likely result in a performance drop as string
comparison is likely more expensive than comparing pointers. Any performance
optimizations are better placed in Boost.TypeIndex.
---
 .../boost/statechart/detail/rtti_policy.hpp   | 41 +++++++++----------
 1 file changed, 19 insertions(+), 22 deletions(-)

diff --git a/include/boost/statechart/detail/rtti_policy.hpp b/include/boost/statechart/detail/rtti_policy.hpp
index f12fb057..71428f3c 100644
--- a/include/boost/statechart/detail/rtti_policy.hpp
+++ b/include/boost/statechart/detail/rtti_policy.hpp
@@ -11,11 +11,13 @@
 #include <boost/assert.hpp>
 #include <boost/config.hpp> // BOOST_MSVC
 #include <boost/detail/workaround.hpp>
+#if !defined(BOOST_STATECHART_USE_NATIVE_RTTI)
+#include <boost/type_index/ctti_type_index.hpp>
+#endif
 
 #include <typeinfo> // std::type_info
 
 
-
 namespace boost
 {
 namespace statechart
@@ -24,10 +26,12 @@ namespace detail
 {
 
 
+#if !defined(BOOST_STATECHART_USE_NATIVE_RTTI)
 
 //////////////////////////////////////////////////////////////////////////////
 struct id_provider
 {
+  const boost::typeindex::ctti_type_index::type_info_t* const pTypeInfo;
   const void * pCustomId_;
   #if defined( BOOST_ENABLE_ASSERT_HANDLER ) || !defined( NDEBUG )
   const std::type_info * pCustomIdType_;
@@ -41,8 +45,14 @@ struct id_holder
 };
 
 template< class MostDerived >
-id_provider id_holder< MostDerived >::idProvider_;
+id_provider id_holder< MostDerived >::idProvider_ =
+{
+  &boost::typeindex::ctti_type_index::type_id< MostDerived >().type_info(),
+  0,
+  0
+};
 
+#endif // !defined(BOOST_STATECHART_USE_NATIVE_RTTI)
 
 
 //////////////////////////////////////////////////////////////////////////////
@@ -76,8 +86,8 @@ struct rtti_policy
 
   typedef bool id_provider_type; // dummy
   #else
-  typedef const void * id_type;
-  typedef const id_provider * id_provider_type;
+  typedef boost::typeindex::ctti_type_index id_type;
+  typedef const id_provider* id_provider_type;
   #endif
 
   ////////////////////////////////////////////////////////////////////////////
@@ -93,7 +103,7 @@ struct rtti_policy
         #ifdef BOOST_STATECHART_USE_NATIVE_RTTI
         return id_type( typeid( *this ) );
         #else
-        return idProvider_;
+        return id_type( *idProvider_->pTypeInfo );
         #endif
       }
 
@@ -112,25 +122,13 @@ struct rtti_policy
     #ifdef BOOST_STATECHART_USE_NATIVE_RTTI
       rtti_base_type( id_provider_type ) {}
 
-      ////////////////////////////////////////////////////////////////////////
-      #if BOOST_WORKAROUND( __GNUC__, BOOST_TESTED_AT( 4 ) )
-      // We make the destructor virtual for GCC because with this compiler
-      // there is currently no way to disable the "has virtual functions but
-      // non-virtual destructor" warning on a class by class basis. Although
-      // it can be done on the compiler command line with
-      // -Wno-non-virtual-dtor, this is undesirable as this would also
-      // suppress legitimate warnings for types that are not states.
-      virtual ~rtti_base_type() {}
-      #else
-      ~rtti_base_type() {}
-      #endif
-
-    private:
       ////////////////////////////////////////////////////////////////////////
       // For typeid( *this ) to return a value that corresponds to the most-
       // derived type, we need to have a vptr. Since this type does not
       // contain any virtual functions we need to artificially declare one so.
-      virtual void dummy() {}
+      // A virtual destructor will do.
+      virtual ~rtti_base_type() {}
+
     #else
       rtti_base_type(
         id_provider_type idProvider
@@ -158,7 +156,7 @@ struct rtti_policy
         #ifdef BOOST_STATECHART_USE_NATIVE_RTTI
         return id_type( typeid( const MostDerived ) );
         #else
-        return &id_holder< MostDerived >::idProvider_;
+        return boost::typeindex::ctti_type_index::type_id< MostDerived >();
         #endif
       }
 
@@ -204,5 +202,4 @@ struct rtti_policy
 } // namespace boost
 
 
-
 #endif