Fixes #4817.

[SVN r66410]

doc/acknowledgments.html

@@ -80,6 +80,8 @@
 
     <li>Joaqu&iacute;n M L&oacute;pez Mu&ntilde;oz for his broken allocator
     workaround in boost/detail/allocator_utilities.hpp</li>
+    
+    <li>Igor R for uncovering and reporting several bugs</li>
   </ul>
 
   <p>Thanks for feedback and/or encouragement go to:</p>
@@ -90,17 +92,16 @@
   Gregor, Gustavo Guerra, Aleksey Gurtovoy, Federico J. Fern&aacute;ndez,
   Iain K. Hanson, Steve Hawkes, David B. Held, J&uuml;rgen Hunold, Sean
   Kelly, Oliver Kowalke, Thomas Mathys, Simon Meiklejohn, Jiang Miao, Johan
-  Nilsson, Matthieu Paindavoine, Chris Paulse, Igor R, Yuval Ronen, Chris
-  Russell, Bryan Silverthorn, Rob Stewart, Kwee Heong Tan, Marcin Tustin,
-  Vincent N. Virgilio, Gang Wang, Steven Watanabe, Richard Webb and Scott
-  Woods.</p>
+  Nilsson, Matthieu Paindavoine, Chris Paulse, Yuval Ronen, Chris Russell,
+  Bryan Silverthorn, Rob Stewart, Kwee Heong Tan, Marcin Tustin, Vincent N.
+  Virgilio, Gang Wang, Steven Watanabe, Richard Webb and Scott Woods.</p>
   <hr>
 
   <p><a href="http://validator.w3.org/check?uri=referer"><img border="0" src=
   "../../../doc/images/valid-html401.png" alt="Valid HTML 4.01 Transitional"
   height="31" width="88"></a></p>
 
-  <p>Revised 04 April, 2010</p>
+  <p>Revised 06 November, 2010</p>
 
   <p><i>Copyright &copy; 2003-2010 <a href="contact.html">Andreas Huber
   D&ouml;nni</a></i></p>

doc/future_and_history.html

@@ -127,6 +127,12 @@
 
   <p>(<font color="#FF0000">red</font> = points raised during formal
   review)</p>
+  <p>1.46.0</p>
+  <ul>
+    <li>Fixed Bug #4817 (The order of deferred events is not preserved under
+    certain circumstances), reported by Igor R</li>
+  </ul>
+
   <p>1.43.0</p>
   <ul>
     <li>Generalized the context() functions so that they can also return a

doc/reference.html

@@ -1069,8 +1069,8 @@ void <a name="process_event" id=
     <li>If the return value of <code>ExceptionTranslator::operator()()</code>
     is equal to the one of <code>simple_state&lt;&gt;::defer_event()</code>
     then the return value of <code>currentEvent.<a href=
-    "#intrusive_from_this">intrusive_from_this</a>()</code> is stored in a
-    state-specific queue. Continues with step 11</li>
+    "#intrusive_from_this">intrusive_from_this</a>()</code> is stored in the
+    deferred events queue. Continues with step 11</li>
 
     <li>If the return value of <code>ExceptionTranslator::operator()()</code>
     is equal to the one of <code>simple_state&lt;&gt;::discard_event()</code>
@@ -2160,8 +2160,10 @@ namespace statechart
 <a name="simple_statedtor" id="simple_statedtor">~simple_state</a>();
 </pre>
 
-  <p><b>Effects</b>: Pushes all events deferred by the state into the posted
-  events queue</p>
+  <p><b>Effects</b>: If the state has deferral reactions of which at least
+  one has been triggered during the lifetime of the state then the contents
+  of the deferred events queue is moved to the front of the posted events
+  queue.</p>
 
   <h3>Class template <code>simple_state</code> modifier functions</h3>
   <pre>
@@ -3579,9 +3581,9 @@ namespace statechart
   "../../../doc/images/valid-html401.png" alt="Valid HTML 4.01 Transitional"
   height="31" width="88"></a></p>
 
-  <p>Revised 06 January, 2008</p>
+  <p>Revised 06 November, 2010</p>
 
-  <p><i>Copyright &copy; 2003-2008 <a href="contact.html">Andreas Huber
+  <p><i>Copyright &copy; 2003-2010 <a href="contact.html">Andreas Huber
   D&ouml;nni</a></i></p>
 
   <p><i>Distributed under the Boost Software License, Version 1.0. (See

include/boost/statechart/simple_state.hpp

@@ -365,7 +365,7 @@ class simple_state : public detail::simple_state_base_type< MostDerived,
       {
         if ( this->deferred_events() )
         {
-          outermost_context_base().release_events( this );
+          outermost_context_base().release_events();
         }
 
         pContext_->remove_inner_state( orthogonal_position::value );
@@ -490,19 +490,12 @@ class simple_state : public detail::simple_state_base_type< MostDerived,
 
       // At this point we can only safely access pContext_ if the handler did
       // not return do_discard_event!
-      switch ( reactionResult )
+      if ( reactionResult == detail::do_forward_event )
       {
-        case detail::do_forward_event:
-          // TODO: The following call to react_impl of our outer state should
-          // be made with a context_type:: prefix to call directly instead of
-          // virtually. For some reason the compiler complains...
-          reactionResult = pContext_->react_impl( evt, eventType );
-          break;
-        case detail::do_defer_event:
-          outermost_context_base().defer_event( evt, this );
-          break;
-        default:
-          break;
+        // TODO: The following call to react_impl of our outer state should
+        // be made with a context_type:: prefix to call directly instead of
+        // virtually. For some reason the compiler complains...
+        reactionResult = pContext_->react_impl( evt, eventType );
       }
 
       return reactionResult;

include/boost/statechart/state_machine.hpp

@@ -272,7 +272,14 @@ class state_machine : noncopyable
 
     void process_event( const event_base_type & evt )
     {
-      send_event( evt );
+      if ( send_event( evt ) == detail::do_defer_event )
+      {
+        // Before deferring, a reaction could post other events, which still
+        // need to be processed. This is why we push the event at the front.
+        eventQueue_.push_front( evt.intrusive_from_this() );
+        eventQueueBegin_ = ++eventQueue_.begin();
+      }
+
       process_queued_events();
     }
 
@@ -408,6 +415,7 @@ class state_machine : noncopyable
   protected:
     //////////////////////////////////////////////////////////////////////////
     state_machine() :
+      eventQueueBegin_( eventQueue_.begin() ),
       currentStatesEnd_( currentStates_.end() ),
       pOutermostState_( 0 ),
       isInnermostCommonOuter_( false ),
@@ -638,26 +646,9 @@ class state_machine : noncopyable
     }
 
 
-    void defer_event(
-      const event_base_type & evt,
-      const state_base_type * pForState )
+    void release_events()
     {
-      deferredMap_[ pForState ].push_back( evt.intrusive_from_this() );
-    }
-
-    void release_events( const state_base_type * pForState )
-    {
-      const typename deferred_map_type::iterator pFound =
-        deferredMap_.find( pForState );
-
-      // We are not guaranteed to find an entry because a state is marked for
-      // having deferred events _before_ the event is actually deferred. An
-      // exception might be thrown during deferral.
-      if ( pFound != deferredMap_.end() )
-      {
-        eventQueue_.splice( eventQueue_.end(), pFound->second );
-        deferredMap_.erase( pFound );
-      }
+      eventQueueBegin_ = eventQueue_.begin();
     }
 
 
@@ -880,7 +871,7 @@ class state_machine : noncopyable
     friend class terminator;
 
 
-    void send_event( const event_base_type & evt )
+    detail::reaction_result send_event( const event_base_type & evt )
     {
       terminator guard( *this, &evt );
       BOOST_ASSERT( get_pointer( pOutermostUnstableState_ ) == 0 );
@@ -908,16 +899,33 @@ class state_machine : noncopyable
       {
         polymorphic_downcast< MostDerived * >( this )->unconsumed_event( evt );
       }
+
+      return reactionResult;
     }
 
 
     void process_queued_events()
     {
-      while ( !eventQueue_.empty() )
+      while ( eventQueueBegin_ != eventQueue_.end() )
       {
-        const event_base_ptr_type pCurrentEvent( eventQueue_.front() );
-        eventQueue_.pop_front();
-        send_event( *pCurrentEvent );
+        const event_base_ptr_type pCurrentEvent( *eventQueueBegin_ );
+
+        try
+        {
+          if ( send_event( *pCurrentEvent ) == detail::do_defer_event )
+          {
+            ++eventQueueBegin_;
+          }
+          else
+          {
+            eventQueueBegin_ = eventQueue_.erase( eventQueueBegin_ );
+          }
+        }
+        catch ( ... )
+        {
+          eventQueueBegin_ = eventQueue_.erase( eventQueueBegin_ );
+          throw;
+        }
       }
     }
 
@@ -928,11 +936,11 @@ class state_machine : noncopyable
 
       if ( !terminated() )
       {
-        // this also empties deferredMap_
         terminate_impl( *pOutermostState_, performFullExit );
       }
 
       eventQueue_.clear();
+      eventQueueBegin_ = eventQueue_.begin();
       shallowHistoryMap_.clear();
       deepHistoryMap_.clear();
     }
@@ -1075,7 +1083,7 @@ class state_machine : noncopyable
 
 
     event_queue_type eventQueue_;
-    deferred_map_type deferredMap_;
+    typename event_queue_type::iterator eventQueueBegin_;
     state_list_type currentStates_;
     typename state_list_type::iterator currentStatesEnd_;
     state_base_type * pOutermostState_;