From b1dcdc406446a5e1eb5a7e04d984fed91ceb52ec Mon Sep 17 00:00:00 2001
From: Volker Krause <volker.krause@kdab.com>
Date: Tue, 5 Jan 2016 15:17:11 +0100
Subject: [PATCH] Avoid unnecessary detaching of the pending deletions list.

This code seems to be hit three times per frame in a hybrid QQ2/Qt3D app,
quickly generating thousands of allocations here via the detach in begin().

Heaptrack confirms they are all gone now.

Change-Id: I7d09f3f5c2b24a2590b701216715055751306e82
Reviewed-by: Sean Harmer <sean.harmer@kdab.com>
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
---
 src/gui/kernel/qopenglcontext.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/gui/kernel/qopenglcontext.cpp b/src/gui/kernel/qopenglcontext.cpp
index 85d05959def..3c033ea39e1 100644
--- a/src/gui/kernel/qopenglcontext.cpp
+++ b/src/gui/kernel/qopenglcontext.cpp
@@ -1459,11 +1459,11 @@ void QOpenGLContextGroupPrivate::deletePendingResources(QOpenGLContext *ctx)
 {
     QMutexLocker locker(&m_mutex);
 
-    QList<QOpenGLSharedResource *> pending = m_pendingDeletion;
+    const QList<QOpenGLSharedResource *> pending = m_pendingDeletion;
     m_pendingDeletion.clear();
 
-    QList<QOpenGLSharedResource *>::iterator it = pending.begin();
-    QList<QOpenGLSharedResource *>::iterator end = pending.end();
+    QList<QOpenGLSharedResource *>::const_iterator it = pending.begin();
+    QList<QOpenGLSharedResource *>::const_iterator end = pending.end();
     while (it != end) {
         (*it)->freeResource(ctx);
         delete *it;