2009-11-02 Benjamin Kosnik <bkoz@redhat.com>

	* include/std/future: Use base class with nested types.
	(__future_base): New.
	(__future_base::_Result_base): From _Future_result_base.
	(__future_base::_Result): From _Future_result.
	(__future_base::_Move_result): From _Move_future_result.
	(__future_base::_Ptr): From _Future_ptr.
	(__future_base::_State): From _Future_state.
	(__basic_future): From _Future_impl.
	* testsuite/30_threads/packaged_task/cons/assign_neg.cc: Adjust line
	numbers.
	* testsuite/30_threads/packaged_task/cons/copy_neg.cc: Same.
	* testsuite/30_threads/shared_future/cons/assign_neg.cc: Same.
	* testsuite/30_threads/unique_future/cons/assign_neg.cc: Same.
	* testsuite/30_threads/unique_future/cons/copy_neg.cc: Same.
	* testsuite/30_threads/promise/cons/assign_neg.cc: Same.
	* testsuite/30_threads/promise/cons/copy_neg.cc: Same.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@153834 138bc75d-0d04-0410-961f-82ee72b054a4

9 files changed, 399 insertions, 336 deletions

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 91d2a598ee5..589671b470b 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,22 @@
+2009-11-02  Benjamin Kosnik  <bkoz@redhat.com>
+
+	* include/std/future: Use base class with nested types.
+	(__future_base): New.
+	(__future_base::_Result_base): From _Future_result_base.
+	(__future_base::_Result): From _Future_result.
+	(__future_base::_Move_result): From _Move_future_result.
+	(__future_base::_Ptr): From _Future_ptr.
+	(__future_base::_State): From _Future_state.
+	(__basic_future): From _Future_impl.
+	* testsuite/30_threads/packaged_task/cons/assign_neg.cc: Adjust line
+	numbers.
+	* testsuite/30_threads/packaged_task/cons/copy_neg.cc: Same.
+	* testsuite/30_threads/shared_future/cons/assign_neg.cc: Same.
+	* testsuite/30_threads/unique_future/cons/assign_neg.cc: Same.
+	* testsuite/30_threads/unique_future/cons/copy_neg.cc: Same.
+	* testsuite/30_threads/promise/cons/assign_neg.cc: Same.
+	* testsuite/30_threads/promise/cons/copy_neg.cc: Same.
+
 2009-10-31  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	* include/std/chrono (struct __common_rep_type): New.
@@ -9,7 +28,7 @@
 	operator/(const duration<>&, const _Rep2&),
 	time_point_cast(const time_point<>&)): Implement resolution of
 	DR 1177 ([Ready] in Santa Cruz), change to not participate to
-	overload resolution if the constraints are not met. 
+	overload resolution if the constraints are not met.
 	* testsuite/20_util/duration/cons/1_neg.cc: Adjust dg-errors.
 	* testsuite/20_util/duration/cons/dr974.cc: Likewise.
 	* testsuite/20_util/duration/requirements/typedefs_neg1.cc: Adjust
diff --git a/libstdc++-v3/include/std/future b/libstdc++-v3/include/std/future
index 00f5c48bcfd..b8c54b6075f 100644
--- a/libstdc++-v3/include/std/future
+++ b/libstdc++-v3/include/std/future
@@ -79,7 +79,7 @@ namespace std
    */
   class future_error : public logic_error
   {
-    error_code _M_code;
+    error_code 			_M_code;
 
   public:
     explicit future_error(future_errc __ec)
@@ -96,252 +96,286 @@ namespace std
   };
 
   // Forward declarations.
-  template<typename _Result>
+  template<typename _Res>
     class unique_future;
 
-  template<typename _Result>
+  template<typename _Res>
     class shared_future;
 
   template<typename> 
     class packaged_task;
 
-  template<typename _Result>
+  template<typename _Res>
     class promise;
 
 #if defined(_GLIBCXX_HAS_GTHREADS) && defined(_GLIBCXX_USE_C99_STDINT_TR1) \
   && defined(_GLIBCXX_ATOMIC_BUILTINS_4)
 
-  // Holds the result of a future
-  struct _Future_result_base
+  /// Base class and enclosing scope.
+  struct __future_base
   {
-    _Future_result_base() = default;
-    _Future_result_base(const _Future_result_base&) = delete;
-    _Future_result_base& operator=(const _Future_result_base&) = delete;
+    /// Base class for results.
+    struct _Result_base
+    {
+      exception_ptr		_M_error;
 
-    exception_ptr _M_error;
+      _Result_base() = default;
+      _Result_base(const _Result_base&) = delete;
+      _Result_base& operator=(const _Result_base&) = delete;
 
-    // _M_destroy() allows derived classes to control deallocation,
-    // which will be needed when allocator support is added to promise.
-    // See http://gcc.gnu.org/ml/libstdc++/2009-06/msg00032.html
-    virtual void _M_destroy() = 0;
-    struct _Deleter
-    {
-      void operator()(_Future_result_base* __fr) const { __fr->_M_destroy(); }
-    };
+      // _M_destroy() allows derived classes to control deallocation,
+      // which will be needed when allocator support is added to promise.
+      // See http://gcc.gnu.org/ml/libstdc++/2009-06/msg00032.html
+      virtual void _M_destroy() = 0;
 
-  protected:
-    ~_Future_result_base();
-  };
+      struct _Deleter
+      {
+	void operator()(_Result_base* __fr) const { __fr->_M_destroy(); }
+      };
 
-  inline _Future_result_base::~_Future_result_base() = default;
+    protected:
+      ~_Result_base();
+    };
 
-  // TODO: use template alias when available
-  /*
-   template<typename _Res>
-     using _Future_ptr = unique_ptr<_Res, _Future_result_base::_Deleter>;
-   */
-  template<typename _Res>
-    struct _Future_ptr
-    {
-      typedef unique_ptr<_Res, _Future_result_base::_Deleter> type;
+    /// Result.
+    template<typename _Res>
+      struct _Result : _Result_base
+      {
+      private:
+	typedef alignment_of<_Res>				__a_of;
+	typedef aligned_storage<sizeof(_Res), __a_of::value>	__align_storage;
+	typedef typename __align_storage::type			__align_type;
+
+	__align_type		_M_storage;
+	bool 			_M_initialized;
+
+      public:
+	_Result() : _M_initialized() { }
+	
+	~_Result()
+	{
+	  if (_M_initialized)
+	    _M_value().~_Res();
+	}
+
+	// Return lvalue, future will add const or rvalue-reference
+	_Res& 
+	_M_value() { return *static_cast<_Res*>(_M_addr()); }
+
+	void
+	_M_set(const _Res& __res)
+	{
+	  ::new (_M_addr()) _Res(__res);
+	  _M_initialized = true;
+	}
+
+	void
+	_M_set(_Res&& __res)
+	{
+	  ::new (_M_addr()) _Res(_Move_result<_Res>::_S_move(__res));
+	  _M_initialized = true;
+	}
+
+      private:
+	void _M_destroy() { delete this; }
+
+	void* _M_addr() { return static_cast<void*>(&_M_storage); }
     };
 
-  // State shared between a promise and one or more associated futures.
-  class _Future_state
-  {
-    typedef _Future_ptr<_Future_result_base>::type _Future_ptr_type;
 
-  public:
-    _Future_state() : _M_result(), _M_retrieved(ATOMIC_FLAG_INIT) { }
+    /// Workaround for CWG issue 664 and c++/34022
+    template<typename _Res, bool = is_scalar<_Res>::value>
+      struct _Move_result;
 
-    _Future_state(const _Future_state&) = delete;
-    _Future_state& operator=(const _Future_state&) = delete;
+     /// Specialization for scalar types returns rvalue not rvalue-reference.
+    template<typename _Res>
+      struct _Move_result<_Res, true>
+      {
+	typedef _Res __rval_type;
+	static _Res _S_move(_Res __res) { return __res; }
+      };
+    
+    /// Specialization for non-scalar types returns rvalue-reference.
+    template<typename _Res>
+      struct _Move_result<_Res, false>
+      {
+	typedef _Res&& __rval_type;
+	static _Res&& _S_move(_Res& __res) { return std::move(__res); }
+      };
+
+
+    // TODO: use template alias when available
+    /*
+      template<typename _Res>
+      using _Ptr = unique_ptr<_Res, _Result_base::_Deleter>;
+    */
+    /// A unique_ptr based on the instantiating type.
+    template<typename _Res>
+      struct _Ptr
+      {
+	typedef unique_ptr<_Res, _Result_base::_Deleter> type;
+      };
 
-    bool
-    is_ready()
-    { return _M_get() != 0; }
 
-    bool
-    has_exception()
+    /// Shared state between a promise and one or more associated futures.
+    class _State
     {
-      _Future_result_base* const __res = _M_get();
-      return __res && !(__res->_M_error == 0);
-    }
+      typedef _Ptr<_Result_base>::type _Ptr_type;
 
-    bool
-    has_value()
-    {
-      _Future_result_base* const __res = _M_get();
-      return __res && (__res->_M_error == 0);
-    }
+      _Ptr_type			_M_result;
+      mutex               	_M_mutex;
+      condition_variable  	_M_cond;
+      atomic_flag         	_M_retrieved;
 
-    _Future_result_base&
-    wait()
-    {
-      unique_lock<mutex> __lock(_M_mutex);
-      if (!_M_ready())
-        _M_cond.wait(__lock, std::bind(&_Future_state::_M_ready, this));
-      return *_M_result;
-    }
+    public:
+      _State() : _M_result(), _M_retrieved(ATOMIC_FLAG_INIT) { }
+
+      _State(const _State&) = delete;
+      _State& operator=(const _State&) = delete;
 
-    template<typename _Rep, typename _Period>
       bool
-      wait_for(const chrono::duration<_Rep, _Period>& __rel)
-      {
-        unique_lock<mutex> __lock(_M_mutex);
-        return _M_ready() || _M_cond.wait_for(__lock, __rel,
-            std::bind(&_Future_state::_M_ready, this));
-      }
+      is_ready()
+      { return _M_get() != 0; }
 
-    template<typename _Clock, typename _Duration>
       bool
-      wait_until(const chrono::time_point<_Clock, _Duration>& __abs)
+      has_exception()
       {
-        unique_lock<mutex> __lock(_M_mutex);
-        return _M_ready() || _M_cond.wait_until(__lock, __abs,
-            std::bind(&_Future_state::_M_ready, this));
+	_Result_base* const __res = _M_get();
+	return __res && !(__res->_M_error == 0);
       }
 
-    void
-    _M_set_result(_Future_ptr_type __res)
-    {
+      bool
+      has_value()
       {
-        lock_guard<mutex> __lock(_M_mutex);
-        if (_M_ready())
-	  __throw_future_error(int(future_errc::promise_already_satisfied));
-        _M_result.swap(__res);
+	_Result_base* const __res = _M_get();
+	return __res && (__res->_M_error == 0);
       }
-      _M_cond.notify_all();
-    }
 
-    void
-    _M_break_promise(_Future_ptr_type __res)
-    {
-      if (static_cast<bool>(__res))
+      _Result_base&
+      wait()
       {
-        __res->_M_error
-          = std::copy_exception(future_error(future_errc::broken_promise));
-        {
-          lock_guard<mutex> __lock(_M_mutex);
-          _M_result.swap(__res);
-        }
-        _M_cond.notify_all();
+	unique_lock<mutex> __lock(_M_mutex);
+	if (!_M_ready())
+	  _M_cond.wait(__lock, std::bind(&_State::_M_ready, this));
+	return *_M_result;
       }
-    }
-
-    // called when this object is passed to a unique_future
-    void
-    _M_set_retrieved_flag()
-    {
-      if (_M_retrieved.test_and_set())
-        __throw_future_error(int(future_errc::future_already_retrieved));
-    }
-
-  private:
-    _Future_result_base*
-    _M_get()
-    {
-      lock_guard<mutex> __lock(_M_mutex);
-      return _M_result.get();
-    }
 
-    bool _M_ready() const { return static_cast<bool>(_M_result); }
-
-    _Future_ptr_type    _M_result;
-    mutex               _M_mutex;
-    condition_variable  _M_cond;
-    atomic_flag         _M_retrieved;
-  };
-
-  // workaround for CWG issue 664 and c++/34022
-  template<typename _Result, bool = is_scalar<_Result>::value>
-    struct _Move_future_result
-    {
-      typedef _Result&& __rval_type;
-      static _Result&& _S_move(_Result& __res) { return std::move(__res); }
-    };
-
-  // specialization for scalar types returns rvalue not rvalue-reference
-  template<typename _Result>
-    struct _Move_future_result<_Result, true>
-    {
-      typedef _Result __rval_type;
-      static _Result _S_move(_Result __res) { return __res; }
-    };
+      template<typename _Rep, typename _Period>
+        bool
+        wait_for(const chrono::duration<_Rep, _Period>& __rel)
+        {
+	  unique_lock<mutex> __lock(_M_mutex);
+	  auto __bound = std::bind(&_State::_M_ready, this);
+	  return _M_ready() || _M_cond.wait_for(__lock, __rel, __bound);
+	}
 
-  template<typename _Result>
-    struct _Future_result : _Future_result_base
-    {
-      _Future_result() : _M_initialized() { }
+      template<typename _Clock, typename _Duration>
+        bool
+        wait_until(const chrono::time_point<_Clock, _Duration>& __abs)
+        {
+	  unique_lock<mutex> __lock(_M_mutex);
+	  auto __bound = std::bind(&_State::_M_ready, this);
+	  return _M_ready() || _M_cond.wait_until(__lock, __abs, __bound);
+	}
 
-      ~_Future_result()
+      void
+      _M_set_result(_Ptr_type __res)
       {
-        if (_M_initialized)
-          _M_value().~_Result();
+	{
+	  lock_guard<mutex> __lock(_M_mutex);
+	  if (_M_ready())
+	    __throw_future_error(int(future_errc::promise_already_satisfied));
+	  _M_result.swap(__res);
+	}
+	_M_cond.notify_all();
       }
 
-      // return lvalue, future will add const or rvalue-reference
-      _Result& _M_value()
-      { return *static_cast<_Result*>(_M_addr()); }
-
       void
-      _M_set(const _Result& __res)
+      _M_break_promise(_Ptr_type __res)
       {
-        ::new (_M_addr()) _Result(__res);
-        _M_initialized = true;
+	if (static_cast<bool>(__res))
+	  {
+	    future_errc __ec(future_errc::broken_promise); // XXX
+	    __res->_M_error = copy_exception(future_error(__ec));
+	    {
+	      lock_guard<mutex> __lock(_M_mutex);
+	      _M_result.swap(__res);
+	    }
+	    _M_cond.notify_all();
+	  }
       }
 
+      // Called when this object is passed to a unique_future.
       void
-      _M_set(_Result&& __res)
+      _M_set_retrieved_flag()
       {
-        typedef _Move_future_result<_Result> _Mover;
-        ::new (_M_addr()) _Result(_Mover::_S_move(__res));
-        _M_initialized = true;
+	if (_M_retrieved.test_and_set())
+	  __throw_future_error(int(future_errc::future_already_retrieved));
       }
 
     private:
-      void _M_destroy() { delete this; }
-
-      void* _M_addr() { return static_cast<void*>(&_M_storage); }
+      _Result_base*
+      _M_get()
+      {
+	lock_guard<mutex> __lock(_M_mutex);
+	return _M_result.get();
+      }
 
-      typename aligned_storage<sizeof(_Result),
-               alignment_of<_Result>::value>::type _M_storage;
-      bool _M_initialized;
+      bool _M_ready() const { return static_cast<bool>(_M_result); }
     };
+  };
 
-  template<typename _Result>
-    struct _Future_result<_Result&> : _Future_result_base
-    {
-      _Future_result() : _M_value_ptr() { }
+  inline __future_base::_Result_base::~_Result_base() = default;
 
-      _Result* _M_value_ptr;
+  /// Partial specialization for reference types.
+  template<typename _Res>
+    struct __future_base::_Result<_Res&> : __future_base::_Result_base
+    {
+      _Result() : _M_value_ptr() { }
 
+      _Res* 			_M_value_ptr;
+      
+    private:
       void _M_destroy() { delete this; }
     };
 
+  /// Explicit specialization for void.
   template<>
-    struct _Future_result<void> : _Future_result_base
+    struct __future_base::_Result<void> : __future_base::_Result_base
     {
+    private:
       void _M_destroy() { delete this; }
     };
 
-  // common implementation for unique_future and shared_future
-  template<typename _Result>
-    class _Future_impl
+
+  /// Common implementation for unique_future and shared_future.
+  template<typename _Res>
+    class __basic_future : public __future_base
     {
+    protected:
+      typedef shared_ptr<_State>		__state_type;
+      typedef __future_base::_Result<_Res>&	__result_type;
+
+    private:
+      __state_type 		_M_state;
+
     public:
-      // disable copying
-      _Future_impl(const _Future_impl&) = delete;
-      _Future_impl& operator=(const _Future_impl&) = delete;
+      // Disable copying.
+      __basic_future(const __basic_future&) = delete;
+      __basic_future& operator=(const __basic_future&) = delete;
 
-      // functions to check state and wait for ready
-      bool is_ready() const { return this->_M_state->is_ready(); }
+      // Functions to check state and wait for ready.
+      bool 
+      is_ready() const { return this->_M_state->is_ready(); }
 
-      bool has_exception() const { return this->_M_state->has_exception(); }
+      bool 
+      has_exception() const { return this->_M_state->has_exception(); }
 
-      bool has_value() const { return this->_M_state->has_value(); }
+      bool 
+      has_value() const { return this->_M_state->has_value(); }
 
-      void wait() const { this->_M_state->wait(); }
+      void 
+      wait() const { this->_M_state->wait(); }
 
       template<typename _Rep, typename _Period>
         bool
@@ -354,22 +388,19 @@ namespace std
         { return this->_M_state->wait_until(__abs); }
 
     protected:
-      // wait for the state to be ready and rethrow any stored exception
-      _Future_result<_Result>&
+      /// Wait for the state to be ready and rethrow any stored exception
+      __result_type
       _M_get_result()
       {
-        _Future_result_base& __res = this->_M_state->wait();
+        _Result_base& __res = this->_M_state->wait();
         if (!(__res._M_error == 0))
           rethrow_exception(__res._M_error);
-        return static_cast<_Future_result<_Result>&>(__res);
+        return static_cast<__result_type>(__res);
       }
 
-      typedef shared_ptr<_Future_state> _State_ptr;
-
-      // construction of a unique_future by promise::get_future()
+      // Construction of a unique_future by promise::get_future()
       explicit
-      _Future_impl(const _State_ptr& __state)
-      : _M_state(__state)
+      __basic_future(const __state_type& __state) : _M_state(__state)
       {
         if (static_cast<bool>(this->_M_state))
           this->_M_state->_M_set_retrieved_flag();
@@ -377,146 +408,149 @@ namespace std
           __throw_future_error(int(future_errc::future_already_retrieved));
       }
 
-      // copy construction from a shared_future
+      // Copy construction from a shared_future
       explicit
-      _Future_impl(const shared_future<_Result>&);
+      __basic_future(const shared_future<_Res>&);
 
-      // move construction from a unique_future
+      // Move construction from a unique_future
       explicit
-      _Future_impl(unique_future<_Result>&&);
-
-      _State_ptr _M_state;
+      __basic_future(unique_future<_Res>&&);
     };
 
-  /// primary template for unique_future
-  template<typename _Result>
-    class unique_future : public _Future_impl<_Result>
+
+  /// Primary template for unique_future.
+  template<typename _Res>
+    class unique_future : public __basic_future<_Res>
     {
-      typedef _Move_future_result<_Result> _Mover;
+      friend class promise<_Res>;
+
+      typedef __basic_future<_Res> _Base_type;
+      typedef typename _Base_type::__state_type __state_type;
+      typedef __future_base::_Move_result<_Res> _Mover;
+
+      explicit
+      unique_future(const __state_type& __state) : _Base_type(__state) { }
 
     public:
       /// Move constructor
       unique_future(unique_future&& __uf) : _Base_type(std::move(__uf)) { }
 
-      // disable copying
+      // Disable copying
       unique_future(const unique_future&) = delete;
       unique_future& operator=(const unique_future&) = delete;
 
-      // retrieving the value
+      /// Retrieving the value
       typename _Mover::__rval_type
       get()
       { return _Mover::_S_move(this->_M_get_result()._M_value()); }
-
-    private:
-      typedef _Future_impl<_Result> _Base_type;
-      typedef typename _Base_type::_State_ptr _State_ptr;
-
-      friend class promise<_Result>;
-
-      explicit
-      unique_future(const _State_ptr& __state) : _Base_type(__state) { }
     };
  
-  // partial specialization for unique_future<R&>
-  template<typename _Result>
-    class unique_future<_Result&> : public _Future_impl<_Result&>
+  /// Partial specialization for unique_future<R&>
+  template<typename _Res>
+    class unique_future<_Res&> : public __basic_future<_Res&>
     {
+      friend class promise<_Res&>;
+
+      typedef __basic_future<_Res&> _Base_type;
+      typedef typename _Base_type::__state_type __state_type;
+
+      explicit
+      unique_future(const __state_type& __state) : _Base_type(__state) { }
+
     public:
       /// Move constructor
       unique_future(unique_future&& __uf) : _Base_type(std::move(__uf)) { }
 
-      // disable copying
+      // Disable copying
       unique_future(const unique_future&) = delete;
       unique_future& operator=(const unique_future&) = delete;
 
-      // retrieving the value
-      _Result& get() { return *this->_M_get_result()._M_value_ptr; }
+      /// Retrieving the value
+      _Res& 
+      get() { return *this->_M_get_result()._M_value_ptr; }
+    };
 
-    private:
-      typedef _Future_impl<_Result&>           _Base_type;
-      typedef typename _Base_type::_State_ptr _State_ptr;
+  /// Explicit specialization for unique_future<void>
+  template<>
+    class unique_future<void> : public __basic_future<void>
+    {
+      friend class promise<void>;
 
-      friend class promise<_Result&>;
+      typedef __basic_future<void> _Base_type;
+      typedef typename _Base_type::__state_type __state_type;
 
       explicit
-      unique_future(const _State_ptr& __state) : _Base_type(__state) { }
-    };
+      unique_future(const __state_type& __state) : _Base_type(__state) { }
 
-  // specialization for unique_future<void>
-  template<>
-    class unique_future<void> : public _Future_impl<void>
-    {
     public:
       /// Move constructor
       unique_future(unique_future&& __uf) : _Base_type(std::move(__uf)) { }
 
-      // disable copying
+      // Disable copying
       unique_future(const unique_future&) = delete;
       unique_future& operator=(const unique_future&) = delete;
 
-      // retrieving the value
-      void get() { this->_M_get_result(); }
-
-    private:
-      typedef _Future_impl<void> _Base_type;
-      typedef _Base_type::_State_ptr _State_ptr;
-
-      friend class promise<void>;
-
-      explicit
-      unique_future(const _State_ptr& __state) : _Base_type(__state) { }
+      /// Retrieving the value
+      void 
+      get() { this->_M_get_result(); }
     };
 
-  /// primary template for shared_future
-  template<typename _Result>
-    class shared_future : public _Future_impl<_Result>
+
+  /// Primary template for shared_future.
+  template<typename _Res>
+    class shared_future : public __basic_future<_Res>
     {
+      typedef __basic_future<_Res> _Base_type;
+
     public:
       /// Copy constructor
       shared_future(const shared_future& __sf) : _Base_type(__sf) { }
 
       /// Construct from a unique_future rvalue
-      shared_future(unique_future<_Result>&& __uf)
+      shared_future(unique_future<_Res>&& __uf)
       : _Base_type(std::move(__uf))
       { }
 
       shared_future& operator=(const shared_future&) = delete;
 
-      // retrieving the value
-      const _Result&
+      /// Retrieving the value
+      const _Res&
       get()
-      { return this->_M_get_result()._M_value(); }
-
-    private:
-      typedef _Future_impl<_Result> _Base_type;
+      { 
+	typename _Base_type::__result_type __r = this->_M_get_result();
+	_Res& __rs(__r._M_value());
+	return __rs;
+      }
     };
  
-  // partial specialization for shared_future<R&>
-  template<typename _Result>
-    class shared_future<_Result&> : public _Future_impl<_Result&>
+  /// Partial specialization for shared_future<R&>
+  template<typename _Res>
+    class shared_future<_Res&> : public __basic_future<_Res&>
     {
+      typedef __basic_future<_Res&>           _Base_type;
+
     public:
       /// Copy constructor
       shared_future(const shared_future& __sf) : _Base_type(__sf) { }
 
       /// Construct from a unique_future rvalue
-      shared_future(unique_future<_Result&>&& __uf)
+      shared_future(unique_future<_Res&>&& __uf)
       : _Base_type(std::move(__uf))
       { }
 
       shared_future& operator=(const shared_future&) = delete;
 
-      // retrieving the value
-      _Result& get() { return *this->_M_get_result()._M_value_ptr; }
-
-    private:
-      typedef _Future_impl<_Result&>           _Base_type;
+      /// Retrieving the value
+      _Res& 
+      get() { return *this->_M_get_result()._M_value_ptr; }
     };
 
-  // specialization for shared_future<void>
+  /// Explicit specialization for shared_future<void>
   template<>
-    class shared_future<void> : public _Future_impl<void>
+    class shared_future<void> : public __basic_future<void>
     {
+      typedef __basic_future<void> _Base_type;
+
     public:
       /// Copy constructor
       shared_future(const shared_future& __sf) : _Base_type(__sf) { }
@@ -528,33 +562,39 @@ namespace std
 
       shared_future& operator=(const shared_future&) = delete;
 
-      // retrieving the value
-      void get() { this->_M_get_result(); }
-
-    private:
-      typedef _Future_impl<void> _Base_type;
+      // Retrieving the value
+      void 
+      get() { this->_M_get_result(); }
     };
 
-  // now we can define the protected _Future_impl constructors
-
-  template<typename _Result>
-    _Future_impl<_Result>::_Future_impl(const shared_future<_Result>& __sf)
+  // Now we can define the protected __basic_future constructors.
+  template<typename _Res>
+    __basic_future<_Res>::__basic_future(const shared_future<_Res>& __sf)
     : _M_state(__sf._M_state)
     { }
 
-  template<typename _Result>
-    _Future_impl<_Result>::_Future_impl(unique_future<_Result>&& __uf)
+  template<typename _Res>
+    __basic_future<_Res>::__basic_future(unique_future<_Res>&& __uf)
     : _M_state(std::move(__uf._M_state))
     { }
 
-  /// primary template for promise
-  template<typename _Result>
+
+  /// Primary template for promise
+  template<typename _Res>
     class promise
     {
+      template<typename> friend class packaged_task;
+
+      typedef __future_base::_State 		_State;
+      typedef __future_base::_Move_result<_Res>	_Mover;
+      typedef __future_base::_Result<_Res>	result_type;
+      
+      shared_ptr<_State>                        _M_future;
+      typename __future_base::_Ptr<result_type>::type	_M_storage;
+
     public:
       promise()
-      : _M_future(std::make_shared<_Future_state>()),
-      _M_storage(new _Future_result<_Result>())
+      : _M_future(std::make_shared<_State>()), _M_storage(new result_type())
       { }
 
       promise(promise&& __rhs)
@@ -579,7 +619,7 @@ namespace std
           _M_future->_M_break_promise(std::move(_M_storage));
       }
 
-      // assignment
+      // Assignment
       promise&
       operator=(promise&& __rhs)
       {
@@ -596,14 +636,14 @@ namespace std
         _M_storage.swap(__rhs._M_storage);
       }
 
-      // retrieving the result
-      unique_future<_Result>
+      // Retrieving the result
+      unique_future<_Res>
       get_future()
-      { return unique_future<_Result>(_M_future); }
+      { return unique_future<_Res>(_M_future); }
 
-      // setting the result
+      // Setting the result
       void
-      set_value(const _Result& __r)
+      set_value(const _Res& __r)
       {
         if (!_M_satisfied())
           _M_storage->_M_set(__r);
@@ -611,7 +651,7 @@ namespace std
       }
 
       void
-      set_value(_Result&& __r)
+      set_value(_Res&& __r)
       {
         if (!_M_satisfied())
           _M_storage->_M_set(_Mover::_S_move(__r));
@@ -627,26 +667,29 @@ namespace std
       }
 
     private:
-      template<typename> friend class packaged_task;
-      typedef _Move_future_result<_Result> _Mover;
       bool _M_satisfied() { return !static_cast<bool>(_M_storage); }
-      shared_ptr<_Future_state>                           _M_future;
-      typename _Future_ptr<_Future_result<_Result>>::type _M_storage;
     };
 
-  // partial specialization for promise<R&>
-  template<typename _Result>
-    class promise<_Result&>
+  /// Partial specialization for promise<R&>
+  template<typename _Res>
+    class promise<_Res&>
     {
+      template<typename> friend class packaged_task;
+      typedef __future_base::_State 		_State;
+ 
+      typedef __future_base::_Result<_Res&> result_type;
+
+      shared_ptr<_State>                        _M_future;
+      typename __future_base::_Ptr<result_type>::type  _M_storage;
+
     public:
       promise()
-      : _M_future(std::make_shared<_Future_state>()),
-      _M_storage(new _Future_result<_Result&>())
+      : _M_future(std::make_shared<_State>()), _M_storage(new result_type())
       { }
 
       promise(promise&& __rhs)
-      : _M_future(std::move(__rhs._M_future)),
-      _M_storage(std::move(__rhs._M_storage))
+      : _M_future(std::move(__rhs._M_future)), 
+	_M_storage(std::move(__rhs._M_storage))
       { }
 
       // TODO: requires allocator concepts
@@ -666,7 +709,7 @@ namespace std
           _M_future->_M_break_promise(std::move(_M_storage));
       }
 
-      // assignment
+      // Assignment
       promise&
       operator=(promise&& __rhs)
       {
@@ -683,14 +726,14 @@ namespace std
         _M_storage.swap(__rhs._M_storage);
       }
 
-      // retrieving the result
-      unique_future<_Result&>
+      // Retrieving the result
+      unique_future<_Res&>
       get_future()
-      { return unique_future<_Result&>(_M_future); }
+      { return unique_future<_Res&>(_M_future); }
 
-      // setting the result
+      // Setting the result
       void
-      set_value(_Result& __r)
+      set_value(_Res& __r)
       {
         if (!_M_satisfied())
           _M_storage->_M_value_ptr = &__r;
@@ -706,20 +749,24 @@ namespace std
       }
 
     private:
-      template<typename> friend class packaged_task;
       bool _M_satisfied() { return !static_cast<bool>(_M_storage); }
-      shared_ptr<_Future_state>                             _M_future;
-      typename _Future_ptr<_Future_result<_Result&>>::type  _M_storage;
     };
 
-  // specialization for promise<void>
+  /// Explicit specialization for promise<void>
   template<>
     class promise<void>
     {
+      template<typename> friend class packaged_task;
+      typedef __future_base::_State 		_State;
+      typedef __future_base::_Result<void>	result_type;
+
+      shared_ptr<__future_base::_State>                 _M_future;
+      typename __future_base::_Ptr<result_type>::type   _M_storage;
+
     public:
       promise()
-      : _M_future(std::make_shared<_Future_state>()),
-      _M_storage(new _Future_result<void>())
+      : _M_future(std::make_shared<_State>()),
+	_M_storage(new result_type())
       { }
 
       promise(promise&& __rhs)
@@ -744,7 +791,7 @@ namespace std
           _M_future->_M_break_promise(std::move(_M_storage));
       }
 
-      // assignment
+      // Assignment
       promise&
       operator=(promise&& __rhs)
       {
@@ -761,12 +808,12 @@ namespace std
         _M_storage.swap(__rhs._M_storage);
       }
 
-      // retrieving the result
+      // Retrieving the result
       unique_future<void>
       get_future()
       { return unique_future<void>(_M_future); }
 
-      // setting the result
+      // Setting the result
       void
       set_value()
       {
@@ -782,53 +829,54 @@ namespace std
       }
 
     private:
-      template<typename> friend class packaged_task;
       bool _M_satisfied() { return !static_cast<bool>(_M_storage); }
-      shared_ptr<_Future_state>                 _M_future;
-      _Future_ptr<_Future_result<void>>::type   _M_storage;
     };
 
   // TODO: requires allocator concepts
   /*
-  template<typename _Result, class Alloc>
-    concept_map UsesAllocator<promise<_Result>, Alloc>
+  template<typename _Res, class Alloc>
+    concept_map UsesAllocator<promise<_Res>, Alloc>
     {
       typedef Alloc allocator_type;
     }
    */
-
-  template<typename _Result, typename... _ArgTypes>
+  /// Primary template.
+  template<typename _Res, typename... _ArgTypes>
     struct _Run_task
     {
       static void
-      _S_run(promise<_Result>& __p, function<_Result(_ArgTypes...)>& __f,
-          _ArgTypes... __args)
+      _S_run(promise<_Res>& __p, function<_Res(_ArgTypes...)>& __f,
+	     _ArgTypes... __args)
       {
         __p.set_value(__f(std::forward<_ArgTypes>(__args)...));
       }
     };
 
-  // specialization used by packaged_task<void(...)>
+  /// Specialization used by packaged_task<void(...)>
   template<typename... _ArgTypes>
     struct _Run_task<void, _ArgTypes...>
     {
       static void
       _S_run(promise<void>& __p, function<void(_ArgTypes...)>& __f,
-          _ArgTypes... __args)
+	     _ArgTypes... __args)
       {
         __f(std::forward<_ArgTypes>(__args)...);
         __p.set_value();
       }
     };
 
+
   /// packaged_task
-  template<typename _Result, typename... _ArgTypes>
-    class packaged_task<_Result(_ArgTypes...)>
+  template<typename _Res, typename... _ArgTypes>
+    class packaged_task<_Res(_ArgTypes...)>
     {
+      function<_Res(_ArgTypes...)>   _M_task;
+      promise<_Res>                  _M_promise;
+
     public:
-      typedef _Result result_type;
+      typedef _Res result_type;
 
-      // construction and destruction
+      // Construction and destruction
       packaged_task() { }
 
       template<typename _Fn>
@@ -840,7 +888,7 @@ namespace std
         packaged_task(_Fn&& __fn) : _M_task(std::move(__fn)) { }
 
       explicit
-      packaged_task(_Result(*__fn)(_ArgTypes...)) : _M_task(__fn) { }
+      packaged_task(_Res(*__fn)(_ArgTypes...)) : _M_task(__fn) { }
 
       // TODO: requires allocator concepts
       /*
@@ -859,11 +907,11 @@ namespace std
 
       ~packaged_task() = default;
 
-      // no copy
+      // No copy
       packaged_task(packaged_task&) = delete;
       packaged_task& operator=(packaged_task&) = delete;
 
-      // move support
+      // Move support
       packaged_task(packaged_task&& __other)
       { this->swap(__other); }
 
@@ -882,8 +930,8 @@ namespace std
 
       explicit operator bool() const { return static_cast<bool>(_M_task); }
 
-      // result retrieval
-      unique_future<_Result>
+      // Result retrieval
+      unique_future<_Res>
       get_future()
       {
         __try
@@ -900,7 +948,7 @@ namespace std
         }
       }
 
-      // execution
+      // Execution
       void
       operator()(_ArgTypes... __args)
       {
@@ -915,7 +963,7 @@ namespace std
 
         __try
         {
-          _Run_task<_Result, _ArgTypes...>::_S_run(_M_promise, _M_task,
+          _Run_task<_Res, _ArgTypes...>::_S_run(_M_promise, _M_task,
               std::forward<_ArgTypes>(__args)...);
         }
         __catch (...)
@@ -924,11 +972,7 @@ namespace std
         }
       }
 
-      void reset() { promise<_Result>().swap(_M_promise); }
-
-    private:
-      function<_Result(_ArgTypes...)>   _M_task;
-      promise<_Result>                  _M_promise;
+      void reset() { promise<_Res>().swap(_M_promise); }
     };
 
 #endif // _GLIBCXX_HAS_GTHREADS && _GLIBCXX_USE_C99_STDINT_TR1
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/assign_neg.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/assign_neg.cc
index 588a27e0dde..db3baf35772 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/assign_neg.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/assign_neg.cc
@@ -33,4 +33,4 @@ void test01()
 }
 
 // { dg-error "used here" "" { target *-*-* } 32 }
-// { dg-error "deleted function" "" { target *-*-* } 864 }
+// { dg-error "deleted function" "" { target *-*-* } 912 }
diff --git a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/copy_neg.cc b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/copy_neg.cc
index d0d0622cf59..8e57d3198f4 100644
--- a/libstdc++-v3/testsuite/30_threads/packaged_task/cons/copy_neg.cc
+++ b/libstdc++-v3/testsuite/30_threads/packaged_task/cons/copy_neg.cc
@@ -32,4 +32,4 @@ void test01()
 }
 
 // { dg-error "used here" "" { target *-*-* } 31 }
-// { dg-error "deleted function" "" { target *-*-* } 863 }
+// { dg-error "deleted function" "" { target *-*-* } 911 }
diff --git a/libstdc++-v3/testsuite/30_threads/promise/cons/assign_neg.cc b/libstdc++-v3/testsuite/30_threads/promise/cons/assign_neg.cc
index b97d3ba896e..5e16d145ccc 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/cons/assign_neg.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/cons/assign_neg.cc
@@ -33,4 +33,4 @@ void test01()
 }
 
 // { dg-error "used here" "" { target *-*-* } 32 }
-// { dg-error "deleted function" "" { target *-*-* } 590 }
+// { dg-error "deleted function" "" { target *-*-* } 630 }
diff --git a/libstdc++-v3/testsuite/30_threads/promise/cons/copy_neg.cc b/libstdc++-v3/testsuite/30_threads/promise/cons/copy_neg.cc
index f94cffb09f3..1e857977927 100644
--- a/libstdc++-v3/testsuite/30_threads/promise/cons/copy_neg.cc
+++ b/libstdc++-v3/testsuite/30_threads/promise/cons/copy_neg.cc
@@ -32,4 +32,4 @@ void test01()
 }
 
 // { dg-error "used here" "" { target *-*-* } 31 }
-// { dg-error "deleted function" "" { target *-*-* } 574 }
+// { dg-error "deleted function" "" { target *-*-* } 614 }
diff --git a/libstdc++-v3/testsuite/30_threads/shared_future/cons/assign_neg.cc b/libstdc++-v3/testsuite/30_threads/shared_future/cons/assign_neg.cc
index 61563e3e3ab..26211fe1c76 100644
--- a/libstdc++-v3/testsuite/30_threads/shared_future/cons/assign_neg.cc
+++ b/libstdc++-v3/testsuite/30_threads/shared_future/cons/assign_neg.cc
@@ -35,4 +35,4 @@ void test01()
 }
 
 // { dg-error "used here" "" { target *-*-* } 34 }
-// { dg-error "deleted function" "" { target *-*-* } 483 }
+// { dg-error "deleted function" "" { target *-*-* } 514 }
diff --git a/libstdc++-v3/testsuite/30_threads/unique_future/cons/assign_neg.cc b/libstdc++-v3/testsuite/30_threads/unique_future/cons/assign_neg.cc
index 9783124d2cb..e29148ee785 100644
--- a/libstdc++-v3/testsuite/30_threads/unique_future/cons/assign_neg.cc
+++ b/libstdc++-v3/testsuite/30_threads/unique_future/cons/assign_neg.cc
@@ -35,4 +35,4 @@ void test01()
 }
 
 // { dg-error "used here" "" { target *-*-* } 34 }
-// { dg-error "deleted function" "" { target *-*-* } 403 }
+// { dg-error "deleted function" "" { target *-*-* } 440 }
diff --git a/libstdc++-v3/testsuite/30_threads/unique_future/cons/copy_neg.cc b/libstdc++-v3/testsuite/30_threads/unique_future/cons/copy_neg.cc
index 4b598997522..8134c7d9219 100644
--- a/libstdc++-v3/testsuite/30_threads/unique_future/cons/copy_neg.cc
+++ b/libstdc++-v3/testsuite/30_threads/unique_future/cons/copy_neg.cc
@@ -34,4 +34,4 @@ void test01()
 }
 
 // { dg-error "used here" "" { target *-*-* } 33 }
-// { dg-error "deleted function" "" { target *-*-* } 402 }
+// { dg-error "deleted function" "" { target *-*-* } 439 }