2 files changed, 83 insertions, 1 deletions

diff --git a/src/FbTk/DefaultValue.hh b/src/FbTk/DefaultValue.hh
new file mode 100644
index 0000000..9f52212
--- /dev/null
+++ b/src/FbTk/DefaultValue.hh
@@ -0,0 +1,82 @@
+// DefaultValue.hh
+// Copyright (c) 2007 Fluxbox Team (fluxgen at fluxbox dot org)
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the
+// Software is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+// THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+// DEALINGS IN THE SOFTWARE.
+
+#ifndef FBTK_DEFAULTVALUE_HH
+#define FBTK_DEFAULTVALUE_HH
+
+namespace FbTk {
+
+// classes for overriding default values without having to listen for changes
+template <typename T>
+class DefaultValue {
+public:
+    DefaultValue(const T &def):
+        m_default(def), m_actual(def), m_use_default(true) { }
+
+    inline const T &get() const { return m_use_default ? m_default : m_actual; }
+    inline void set(const T &val) { m_use_default = false; m_actual = val; }
+    inline void restoreDefault() { m_use_default = true; }
+    inline void isDefault() const { return m_use_default; }
+
+    inline DefaultValue<T> &operator =(const T &val) {
+        set(val); return *this;
+    }
+
+    inline operator T() const { return get(); }
+
+private:
+    const T &m_default;
+    T m_actual;
+    bool m_use_default;
+};
+
+// designed for use with built-in types T, thus no need to return references
+template <typename T, typename Receiver>
+class DefaultAccessor {
+public:
+    typedef T (Receiver:: *Accessor)() const;
+    DefaultAccessor(const Receiver &r, Accessor a):
+        m_receiver(r), m_accessor(a), m_actual((r.*a)()),
+        m_use_default(true) { }
+
+    inline const T get() const {
+        return m_use_default ? (m_receiver.*m_accessor)() : m_actual;
+    }
+    inline void set(const T &val) { m_use_default = false; m_actual = val; }
+    inline void restoreDefault() { m_use_default = true; }
+    inline void isDefault() const { return m_use_default; }
+
+    inline DefaultAccessor<T, Receiver> &operator =(const T &val) {
+        set(val); return *this;
+    }
+
+    inline operator T() const { return get(); }
+
+private:
+    const Receiver &m_receiver;
+    Accessor m_accessor;
+    T m_actual;
+    bool m_use_default;
+};
+
+}; // end namespace FbTk
+
+#endif // FBTK_DEFAULTVALUE_HH
diff --git a/src/FbTk/Makefile.am b/src/FbTk/Makefile.am
index 081bd07..0de5475 100644
--- a/src/FbTk/Makefile.am
+++ b/src/FbTk/Makefile.am
@@ -16,7 +16,7 @@ imlib2_SOURCE= ImageImlib2.hh ImageImlib2.cc
 endif
 
 libFbTk_a_SOURCES = App.hh App.cc Color.cc Color.hh Command.hh \
-        ObjectRegistry.hh \
+        ObjectRegistry.hh DefaultValue.hh \
         FileUtil.hh FileUtil.cc \
         EventHandler.hh EventManager.hh EventManager.cc \
         FbWindow.hh FbWindow.cc Font.cc Font.hh FontImp.hh \