[glibmm] Glib::ustring: Add move operators

[Kjell Ahlstedt <kjellahl src gnome org>]

commit c72c8e709888e0bd2bd58bb5d96354d352bd0c5f
Author: Kjell Ahlstedt <kjell ahlstedt bredband net>
Date:   Thu Jan 14 18:59:06 2016 +0100

    Glib::ustring: Add move operators
    
    Bug #760282

 glib/glibmm/ustring.cc |   34 ++++++++++++++++++++++++++++++----
 glib/glibmm/ustring.h  |   21 +++++++++++++++++++--
 2 files changed, 49 insertions(+), 6 deletions(-)
---
diff --git a/glib/glibmm/ustring.cc b/glib/glibmm/ustring.cc
index e8d7511..78b0e5b 100644
--- a/glib/glibmm/ustring.cc
+++ b/glib/glibmm/ustring.cc
@@ -1,6 +1,3 @@
-// -*- c++ -*-
-/* $Id$ */
-
 /* Copyright (C) 2002 The gtkmm Development Team
  *
  * This library is free software; you can redistribute it and/or
@@ -27,7 +24,8 @@
 #include <algorithm>
 #include <iostream>
 #include <cstring>
-# include <stdexcept>
+#include <stdexcept>
+#include <utility> // For std::move()
 #ifdef HAVE_CONFIG_H
 #include <config.h>
 #endif
@@ -298,6 +296,11 @@ ustring::ustring(const ustring& other)
   string_ (other.string_)
 {}
 
+ustring::ustring(ustring&& other)
+:
+  string_ (std::move(other.string_))
+{}
+
 ustring::ustring(const ustring& src, ustring::size_type i, ustring::size_type n)
 :
   string_ ()
@@ -345,6 +348,11 @@ ustring::ustring(const std::string& src)
   string_ (src)
 {}
 
+ustring::ustring(std::string&& src)
+:
+  string_ (std::move(src))
+{}
+
 ustring::~ustring() noexcept
 {}
 
@@ -362,12 +370,24 @@ ustring& ustring::operator=(const ustring& other)
   return *this;
 }
 
+ustring& ustring::operator=(ustring&& other)
+{
+  string_ = std::move(other.string_);
+  return *this;
+}
+
 ustring& ustring::operator=(const std::string& src)
 {
   string_ = src;
   return *this;
 }
 
+ustring& ustring::operator=(std::string&& src)
+{
+  string_ = std::move(src);
+  return *this;
+}
+
 ustring& ustring::operator=(const char* src)
 {
   string_ = src;
@@ -396,6 +416,12 @@ ustring& ustring::assign(const ustring& src)
   return *this;
 }
 
+ustring& ustring::assign(ustring&& src)
+{
+  string_ = std::move(src.string_);
+  return *this;
+}
+
 ustring& ustring::assign(const ustring& src, ustring::size_type i, ustring::size_type n)
 {
   const Utf8SubstrBounds bounds (src.string_, i, n);
diff --git a/glib/glibmm/ustring.h b/glib/glibmm/ustring.h
index a4e2fa8..528a536 100644
--- a/glib/glibmm/ustring.h
+++ b/glib/glibmm/ustring.h
@@ -268,21 +268,36 @@ public:
    */
   ustring(const ustring& other);
 
-  /*! Assign the value of another string to this string.
+  /*! Construct a ustring by moving from another ustring.
+   * @param other A source string.
+   */
+  ustring(ustring&& other);
+
+  /*! Assign the value of another string by copying to this string.
    * @param other A source string.
    */
   ustring& operator=(const ustring& other);
 
+  /*! Assign the value of another string by moving to this string.
+   * @param other A source string.
+   */
+  ustring& operator=(ustring&& other);
+
   /*! Swap contents with another string.
    * @param other String to swap with.
    */
   void swap(ustring& other);
 
-  /*! Construct a ustring as a copy of another std::string.
+  /*! Construct a ustring as a copy of a std::string.
    * @param src A source <tt>std::string</tt> containing text encoded as UTF-8.
    */
   ustring(const std::string& src);
 
+  /*! Construct a ustring by moving from a std::string.
+   * @param src A source <tt>std::string</tt> containing text encoded as UTF-8.
+   */
+  ustring(std::string&& src);
+
   /*! Construct a ustring as a copy of a substring.
    * @param src %Source ustring.
    * @param i Index of first character to copy from.
@@ -324,11 +339,13 @@ public:
 //! @{
 
   ustring& operator=(const std::string& src);
+  ustring& operator=(std::string&& src);
   ustring& operator=(const char* src);
   ustring& operator=(gunichar uc);
   ustring& operator=(char c);
 
   ustring& assign(const ustring& src);
+  ustring& assign(ustring&& src);
   ustring& assign(const ustring& src, size_type i, size_type n);
   ustring& assign(const char* src, size_type n);
   ustring& assign(const char* src);