libdeng2|Widget: Partial tree traversal

Made it possible for Widget::notifyTree() to abort the traversal when encountering a specific widget. Todo: Collect all the arguments into a single NotifyArgs struct so it can be passed more conveniently to child widgets.
skyjake · Jun 11, 2013 · dac008a · dac008a
1 parent ff61400
commit dac008a
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Showing 2 changed files with 26 additions and 9 deletions.
diff --git a/doomsday/libdeng2/include/de/widgets/widget.h b/doomsday/libdeng2/include/de/widgets/widget.h
@@ -148,10 +148,15 @@ class DENG2_PUBLIC Widget
 
     // Utilities.
     String uniqueName(String const &name) const;
-    void notifyTree(void (Widget::*notifyFunc)(),
-                    bool (Widget::*conditionFunc)() const = 0,
-                    void (Widget::*preNotifyFunc)() = 0,
-                    void (Widget::*postNotifyFunc)() = 0);
+    enum NotifyResult {
+        AbortNotify,
+        ContinueNotify
+    };
+    NotifyResult notifyTree(void (Widget::*notifyFunc)(),
+                            bool (Widget::*conditionFunc)() const = 0,
+                            void (Widget::*preNotifyFunc)() = 0,
+                            void (Widget::*postNotifyFunc)() = 0,
+                            Widget *until = 0);
     void notifyTreeReversed(void (Widget::*notifyFunc)(),
                             bool (Widget::*conditionFunc)() const = 0,
                             void (Widget::*preNotifyFunc)() = 0,

diff --git a/doomsday/libdeng2/src/widgets/widget.cpp b/doomsday/libdeng2/src/widgets/widget.cpp
@@ -275,10 +275,11 @@ String Widget::uniqueName(String const &name) const
     return String("#%1.%2").arg(id().asInt64()).arg(name);
 }
 
-void Widget::notifyTree(void (Widget::*notifyFunc)(),
-                        bool (Widget::*conditionFunc)() const,
-                        void (Widget::*preFunc)(),
-                        void (Widget::*postFunc)())
+Widget::NotifyResult Widget::notifyTree(void (Widget::*notifyFunc)(),
+                                        bool (Widget::*conditionFunc)() const,
+                                        void (Widget::*preFunc)(),
+                                        void (Widget::*postFunc)(),
+                                        Widget *until)
 {
     if(preFunc)
     {
@@ -287,17 +288,28 @@ void Widget::notifyTree(void (Widget::*notifyFunc)(),
 
     DENG2_FOR_EACH(Instance::Children, i, d->children)
     {
+        if(*i == until)
+        {
+            return AbortNotify;
+        }
+
         if(conditionFunc && !((*i)->*conditionFunc)())
             continue; // Skip this one.
 
         ((*i)->*notifyFunc)();
-        (*i)->notifyTree(notifyFunc, conditionFunc, preFunc, postFunc);
+
+        if((*i)->notifyTree(notifyFunc, conditionFunc, preFunc, postFunc, until) == AbortNotify)
+        {
+            return AbortNotify;
+        }
     }
 
     if(postFunc)
     {
         (this->*postFunc)();
     }
+
+    return ContinueNotify;
 }
 
 void Widget::notifyTreeReversed(void (Widget::*notifyFunc)(),