Revert commit removing allocator support from packaged_task. Will investigate further

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@319091 91177308-0d34-0410-b5e6-96231b3b80d8

include/future

@@ -328,6 +328,8 @@ public:
     packaged_task() noexcept;
     template <class F>
         explicit packaged_task(F&& f);
+    template <class F, class Allocator>
+        packaged_task(allocator_arg_t, const Allocator& a, F&& f);
     ~packaged_task();
 
     // no copy
@@ -354,6 +356,8 @@ public:
 template <class R>
   void swap(packaged_task<R(ArgTypes...)&, packaged_task<R(ArgTypes...)>&) noexcept;
 
+template <class R, class Alloc> struct uses_allocator<packaged_task<R>, Alloc>;
+
 }  // std
 
 */
@@ -2024,6 +2028,19 @@ public:
              >
         _LIBCPP_INLINE_VISIBILITY
         explicit packaged_task(_Fp&& __f) : __f_(_VSTD::forward<_Fp>(__f)) {}
+    template <class _Fp, class _Allocator,
+              class = typename enable_if
+              <
+                  !is_same<
+                      typename decay<_Fp>::type, 
+                      packaged_task
+                      >::value
+                  >::type
+              >
+        _LIBCPP_INLINE_VISIBILITY
+        packaged_task(allocator_arg_t, const _Allocator& __a, _Fp&& __f)
+             : __f_(allocator_arg, __a, _VSTD::forward<_Fp>(__f)),
+               __p_(allocator_arg, __a) {}
     // ~packaged_task() = default;
 
     // no copy
@@ -2140,6 +2157,19 @@ public:
               >
         _LIBCPP_INLINE_VISIBILITY
         explicit packaged_task(_Fp&& __f) : __f_(_VSTD::forward<_Fp>(__f)) {}
+    template <class _Fp, class _Allocator,
+              class = typename enable_if
+              <
+                  !is_same<
+                      typename decay<_Fp>::type, 
+                      packaged_task
+                      >::value
+                  >::type
+              >    
+        _LIBCPP_INLINE_VISIBILITY
+        packaged_task(allocator_arg_t, const _Allocator& __a, _Fp&& __f)
+             : __f_(allocator_arg, __a, _VSTD::forward<_Fp>(__f)),
+               __p_(allocator_arg, __a) {}
     // ~packaged_task() = default;
 
     // no copy
@@ -2241,6 +2271,10 @@ swap(packaged_task<_Callable>& __x, packaged_task<_Callable>& __y) _NOEXCEPT
     __x.swap(__y);
 }
 
+template <class _Callable, class _Alloc>
+struct _LIBCPP_TEMPLATE_VIS uses_allocator<packaged_task<_Callable>, _Alloc>
+    : public true_type {};
+
 template <class _Rp, class _Fp>
 future<_Rp>
 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES

test/std/thread/futures/futures.task/futures.task.members/ctor2.fail.cpp

@@ -0,0 +1,34 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// UNSUPPORTED: libcpp-has-no-threads
+// UNSUPPORTED: c++98, c++03
+
+// <future>
+
+// class packaged_task<R(ArgTypes...)>
+// template <class F, class Allocator>
+//   packaged_task(allocator_arg_t, const Allocator& a, F&& f);
+// These constructors shall not participate in overload resolution if
+//    decay<F>::type is the same type as std::packaged_task<R(ArgTypes...)>.
+
+#include <future>
+#include <cassert>
+
+#include "test_allocator.h"
+
+struct A {};
+typedef std::packaged_task<A(int, char)> PT;
+typedef volatile std::packaged_task<A(int, char)> VPT;
+
+int main()
+{
+    PT p { std::allocator_arg_t{}, test_allocator<A>{}, VPT {}}; // expected-error {{no matching constructor for initialization of 'PT' (aka 'packaged_task<A (int, char)>')}}
+    // expected-note-re@future:* 1 {{candidate template ignored: {{(disabled by 'enable_if')|(requirement '.*' was not satisfied)}}}}
+}

test/std/thread/futures/futures.task/futures.task.members/ctor_func_alloc.pass.cpp

@@ -16,6 +16,9 @@
 
 // class packaged_task<R(ArgTypes...)>
 
+// template <class F, class Allocator>
+//     explicit packaged_task(allocator_arg_t, const Allocator& a, F&& f);
+
 #include <future>
 #include <cassert>