From ad25389b017c7b42d9d3878341dad49056030422 Mon Sep 17 00:00:00 2001
From: Tim Blechmann <tim@klingt.org>
Date: Mon, 16 May 2011 14:31:27 +0200
Subject: [PATCH] lockfree: use type traits to ensure trivial assignment

Signed-off-by: Tim Blechmann <tim@klingt.org>
---
 boost/lockfree/fifo.hpp  | 27 ++++++++++++---------------
 boost/lockfree/stack.hpp | 24 ++++++++++++------------
 2 files changed, 24 insertions(+), 27 deletions(-)

diff --git a/boost/lockfree/fifo.hpp b/boost/lockfree/fifo.hpp
index 3d085bc..db1b6a9 100644
--- a/boost/lockfree/fifo.hpp
+++ b/boost/lockfree/fifo.hpp
@@ -15,25 +15,21 @@
 #ifndef BOOST_LOCKFREE_FIFO_HPP_INCLUDED
 #define BOOST_LOCKFREE_FIFO_HPP_INCLUDED
 
-#include <boost/lockfree/detail/atomic.hpp>
-#include <boost/lockfree/detail/tagged_ptr.hpp>
-#include <boost/lockfree/detail/freelist.hpp>
-
-#include <boost/static_assert.hpp>
-#include <boost/type_traits/has_trivial_assign.hpp>
-
 #include <memory>               /* std::auto_ptr */
+
+#include <boost/noncopyable.hpp>
 #include <boost/scoped_ptr.hpp>
 #include <boost/shared_ptr.hpp>
-#include <boost/noncopyable.hpp>
+#include <boost/static_assert.hpp>
+#include <boost/type_traits/has_trivial_assign.hpp>
 
-namespace boost
-{
-namespace lockfree
-{
+#include <boost/lockfree/detail/atomic.hpp>
+#include <boost/lockfree/detail/tagged_ptr.hpp>
+#include <boost/lockfree/detail/freelist.hpp>
 
-namespace detail
-{
+namespace boost {
+namespace lockfree {
+namespace detail {
 
 template <typename T, typename freelist_t, typename Alloc>
 class fifo:
@@ -244,6 +240,8 @@ template <typename T,
 class fifo:
     public detail::fifo<T, freelist_t, Alloc>
 {
+    BOOST_STATIC_ASSERT(boost::has_trivial_assign<T>::value);
+
 public:
     //! Construct fifo.
     fifo(void)
@@ -345,5 +343,4 @@ public:
 } /* namespace lockfree */
 } /* namespace boost */
 
-
 #endif /* BOOST_LOCKFREE_FIFO_HPP_INCLUDED */
diff --git a/boost/lockfree/stack.hpp b/boost/lockfree/stack.hpp
index 4fd7c6d..60f7de2 100644
--- a/boost/lockfree/stack.hpp
+++ b/boost/lockfree/stack.hpp
@@ -9,31 +9,30 @@
 #ifndef BOOST_LOCKFREE_STACK_HPP_INCLUDED
 #define BOOST_LOCKFREE_STACK_HPP_INCLUDED
 
-#include <boost/lockfree/detail/atomic.hpp>
 #include <boost/checked_delete.hpp>
-
+#include <boost/noncopyable.hpp>
 #include <boost/static_assert.hpp>
+#include <boost/type_traits/has_trivial_assign.hpp>
 #include <boost/type_traits/is_base_of.hpp>
 
-#include <boost/lockfree/detail/tagged_ptr.hpp>
+#include <boost/lockfree/detail/atomic.hpp>
 #include <boost/lockfree/detail/freelist.hpp>
-#include <boost/noncopyable.hpp>
-
+#include <boost/lockfree/detail/tagged_ptr.hpp>
 
-namespace boost
-{
 
-namespace lockfree
-{
+namespace boost {
+namespace lockfree {
 
-/** It uses a freelist for memory management, freed nodes are pushed to the freelist and not returned to
- *  the os before the stack is destroyed.
+/** The stack class provides a multi-writer/multi-reader stack, pushing and poping is lockfree,
+ *  construction/destruction has to be synchronized. It uses a freelist for memory management,
+ *  freed nodes are pushed to the freelist and not returned to the os before the stack is destroyed.
  *
  *  The memory management of the stack can be controlled via its freelist_t template argument. Two different
  *  freelists can be used. struct caching_freelist_t selects a caching freelist, which can allocate more nodes
  *  from the operating system, and struct static_freelist_t uses a fixed-sized freelist. With a fixed-sized
  *  freelist, the push operation may fail, while with a caching freelist, the push operation may block.
  *
+ *  \b Limitation: The class T is required to have a trivial assignment operator.
  * */
 template <typename T,
           typename freelist_t = caching_freelist_t,
@@ -43,6 +42,8 @@ class stack:
     boost::noncopyable
 {
 private:
+    BOOST_STATIC_ASSERT(boost::has_trivial_assign<T>::value);
+
 #ifndef BOOST_DOXYGEN_INVOKED
     struct node
     {
@@ -181,7 +182,6 @@ private:
 #endif
 };
 
-
 } /* namespace lockfree */
 } /* namespace boost */
 
-- 
2.11.4.GIT