QDBusIntegrator: fix quadratic behavior

Calling QVector::erase(it) in a loop consitutes quadratic
behavior (O(N) function called O(N) times).

Fix by using std::remove_if(), which is linear.

Change-Id: I39c11231d604bc2d9506427bc3411b71d71b5569
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 7 insertions, 8 deletions

diff --git a/src/dbus/qdbusintegrator.cpp b/src/dbus/qdbusintegrator.cpp
index 1aac16119b..0aa9b27750 100644
--- a/src/dbus/qdbusintegrator.cpp
+++ b/src/dbus/qdbusintegrator.cpp
@@ -517,15 +517,14 @@ bool QDBusConnectionPrivate::handleMessage(const QDBusMessage &amsg)
 
 static void huntAndDestroy(QObject *needle, QDBusConnectionPrivate::ObjectTreeNode &haystack)
 {
-    QDBusConnectionPrivate::ObjectTreeNode::DataList::Iterator it = haystack.children.begin();
+    for (auto &node : haystack.children)
+        huntAndDestroy(needle, node);
 
-    while (it != haystack.children.end()) {
-        huntAndDestroy(needle, *it);
-        if (!it->isActive())
-            it = haystack.children.erase(it);
-        else
-            it++;
-    }
+    auto isInactive = [](QDBusConnectionPrivate::ObjectTreeNode &node) { return !node.isActive(); };
+
+    haystack.children.erase(std::remove_if(haystack.children.begin(), haystack.children.end(),
+                                           isInactive),
+                            haystack.children.end());
 
     if (needle == haystack.obj) {
         haystack.obj = 0;