Codechange: Replace window related FOR_ALL with range-based for loops

1 files changed, 62 insertions, 6 deletions

diff --git a/src/window_gui.h b/src/window_gui.h
index 67a799c3d..66c867a54 100644
--- a/src/window_gui.h
+++ b/src/window_gui.h
@@ -810,6 +810,68 @@ public:
 	 * @pre this->IsNewGRFInspectable()
 	 */
 	virtual void ShowNewGRFInspectWindow() const { NOT_REACHED(); }
+
+	/**
+	 * Iterator to iterate all valid Windows
+	 * @tparam T Type of the class/struct that is going to be iterated
+	 * @tparam Tfront Wether we iterate from front
+	 */
+	template <class T, bool Tfront>
+	struct WindowIterator {
+		typedef T value_type;
+		typedef T *pointer;
+		typedef T &reference;
+		typedef size_t difference_type;
+		typedef std::forward_iterator_tag iterator_category;
+
+		explicit WindowIterator(T *start) : w(start)
+		{
+			this->Validate();
+		}
+
+		bool operator==(const WindowIterator &other) const { return this->w == other.w; }
+		bool operator!=(const WindowIterator &other) const { return !(*this == other); }
+		T * operator*() const { return this->w; }
+		WindowIterator & operator++() { this->Next(); this->Validate(); return *this; }
+
+	private:
+		T *w;
+		void Validate() { while (this->w != nullptr && this->w->window_class == WC_INVALID) this->Next(); }
+		void Next() { if (this->w != nullptr) this->w = Tfront ? this->w->z_back : this->w->z_front; }
+	};
+
+	/**
+	 * Iterable ensemble of all valid Windows
+	 * @tparam T Type of the class/struct that is going to be iterated
+	 * @tparam Tfront Wether we iterate from front
+	 */
+	template <class T, bool Tfront>
+	struct Iterate {
+		Iterate(T *from) : from(from) {}
+		WindowIterator<T, Tfront> begin() { return WindowIterator<T, Tfront>(this->from); }
+		WindowIterator<T, Tfront> end() { return WindowIterator<T, Tfront>(nullptr); }
+		bool empty() { return this->begin() == this->end(); }
+	private:
+		T *from;
+	};
+
+	/**
+	 * Returns an iterable ensemble of all valid Window from back to front
+	 * @tparam T Type of the class/struct that is going to be iterated
+	 * @param from index of the first Window to consider
+	 * @return an iterable ensemble of all valid Window
+	 */
+	template <class T = Window>
+	static Iterate<T, false> IterateFromBack(T *from = _z_back_window) { return Iterate<T, false>(from); }
+
+	/**
+	 * Returns an iterable ensemble of all valid Window from front to back
+	 * @tparam T Type of the class/struct that is going to be iterated
+	 * @param from index of the first Window to consider
+	 * @return an iterable ensemble of all valid Window
+	 */
+	template <class T = Window>
+	static Iterate<T, true> IterateFromFront(T *from = _z_front_window) { return Iterate<T, true>(from); }
 };
 
 /**
@@ -888,12 +950,6 @@ void GuiShowTooltips(Window *parent, StringID str, uint paramcount = 0, const ui
 /* widget.cpp */
 int GetWidgetFromPos(const Window *w, int x, int y);
 
-/** Iterate over all windows */
-#define FOR_ALL_WINDOWS_FROM_BACK_FROM(w, start)  for (w = start; w != nullptr; w = w->z_front) if (w->window_class != WC_INVALID)
-#define FOR_ALL_WINDOWS_FROM_FRONT_FROM(w, start) for (w = start; w != nullptr; w = w->z_back) if (w->window_class != WC_INVALID)
-#define FOR_ALL_WINDOWS_FROM_BACK(w)  FOR_ALL_WINDOWS_FROM_BACK_FROM(w, _z_back_window)
-#define FOR_ALL_WINDOWS_FROM_FRONT(w) FOR_ALL_WINDOWS_FROM_FRONT_FROM(w, _z_front_window)
-
 extern Point _cursorpos_drag_start;
 
 extern int _scrollbar_start_pos;