Add StreamHolder

2 files changed, 124 insertions, 0 deletions

diff --git a/paludis/util/files.m4 b/paludis/util/files.m4
index 28a780c77..39c2f2c33 100644
--- a/paludis/util/files.m4
+++ b/paludis/util/files.m4
@@ -79,6 +79,7 @@ add(`sha256',                            `hh', `cc', `gtest')
 add(`sha512',                            `hh', `cc', `gtest')
 add(`simple_parser',                     `hh', `cc', `gtest', `fwd')
 add(`singleton',                         `hh', `impl', `gtest')
+add(`stream_holder',                     `hh')
 add(`stringify',                         `hh', `gtest')
 add(`string_list_stream',                `hh', `cc', `fwd', `gtest')
 add(`strip',                             `hh', `cc', `gtest')
diff --git a/paludis/util/stream_holder.hh b/paludis/util/stream_holder.hh
new file mode 100644
index 000000000..dea8c6f37
--- /dev/null
+++ b/paludis/util/stream_holder.hh
@@ -0,0 +1,123 @@
+/* vim: set sw=4 sts=4 et foldmethod=syntax : */
+
+/*
+ * Copyright (c) 2013 Wouter van Kesteren <woutershep@gmail.com>
+ *
+ * This file is part of the Paludis package manager. Paludis is free software;
+ * you can redistribute it and/or modify it under the terms of the GNU General
+ * Public License version 2, as published by the Free Software Foundation.
+ *
+ * Paludis is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#ifndef PALUDIS_GUARD_PALUDIS_STREAM_HOLDER_HH
+#define PALUDIS_GUARD_PALUDIS_STREAM_HOLDER_HH 1
+
+#include <paludis/util/attributes.hh>
+#include <utility>
+#include <ostream>
+#include <ios>
+
+namespace paludis
+{
+    /**
+     * Holder for a stream so the destructor can throw.
+     */
+    template <typename Stream_>
+    class PALUDIS_VISIBLE StreamHolder
+    {
+        private:
+            Stream_ s;
+            typedef std::basic_ostream<typename Stream_::char_type, typename Stream_::traits_type> ostream_type;
+            typedef std::basic_ios<typename Stream_::char_type, typename Stream_::traits_type> ios_type;
+
+        public:
+            ///\name Basic operations
+            ///\{
+
+            template<typename... Args_>
+            StreamHolder(Args_ && ... args) : s(std::forward<Args_>(args)...)
+            {
+            }
+
+            ///\}
+
+            ///\name Formatted output
+            ///\{
+
+            template <typename T_>
+            StreamHolder<Stream_>& operator<<(T_ && rhs) 
+            {
+                s << std::forward<T_>(rhs);
+                return *this;
+            }
+
+            /**
+             * Overload for stream manipulators (std::endl, std::flush, etc.)
+             *
+             * see 27.7.3.6.3
+             */
+            ostream_type& operator<<(ostream_type& (*rhs)(ostream_type&))
+            {
+                return rhs(s);
+            }
+
+            /**
+             * Overload for stream manipulators (std::endl, std::flush, etc.)
+             *
+             * see 27.7.3.6.3
+             */
+            ostream_type& operator<<(ios_type& (*rhs)(ios_type&))
+            {
+                rhs(s);
+                return s;
+            }
+
+            /**
+             * Overload for stream manipulators (std::endl, std::flush, etc.)
+             *
+             * see 27.7.3.6.3
+             */
+            ostream_type& operator<<(std::ios_base& (*rhs)(std::ios_base&))
+            {
+                rhs(s);
+                return s;
+            }
+
+            ///\}
+
+            ///\name Conversions
+            ///\{
+
+            bool operator!() const
+            {
+                return !s;
+            }
+
+            operator bool() const
+            {
+                return s;
+            }
+
+            operator Stream_&()
+            {
+                return s;
+            }
+
+            operator Stream_*()
+            {
+                return &s;
+            }
+
+            ///\}
+    };
+}
+
+#endif