From 8be2b24705da4bce99b3a3d588aedcfe2eb3f886 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Morten=20S=C3=B8rvig?= <msorvig@trolltech.com>
Date: Tue, 5 May 2009 14:29:44 +0200
Subject: Fix memory leak in QFuture The held results were not cleared by
 QFutureInterface::operator=(QFutureInterface) Add call to
 resultStore().clear(), similar to the destructor. This needs to be done in
 the header since we know the template type here.

Task-number: 252208
Reviewed-by: brad
---
 src/corelib/concurrent/qfutureinterface.h          |  2 ++
 tests/auto/qtconcurrentmap/tst_qtconcurrentmap.cpp | 31 ++++++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/src/corelib/concurrent/qfutureinterface.h b/src/corelib/concurrent/qfutureinterface.h
index 85d03c9..345bebe 100644
--- a/src/corelib/concurrent/qfutureinterface.h
+++ b/src/corelib/concurrent/qfutureinterface.h
@@ -165,6 +165,8 @@ public:
 
     QFutureInterface &operator=(const QFutureInterface &other)
     {
+        if (referenceCountIsOne())
+            resultStore().clear();
         QFutureInterfaceBase::operator=(other);
         return *this;
     }
diff --git a/tests/auto/qtconcurrentmap/tst_qtconcurrentmap.cpp b/tests/auto/qtconcurrentmap/tst_qtconcurrentmap.cpp
index 139eb6e..116f46e 100644
--- a/tests/auto/qtconcurrentmap/tst_qtconcurrentmap.cpp
+++ b/tests/auto/qtconcurrentmap/tst_qtconcurrentmap.cpp
@@ -74,6 +74,7 @@ private slots:
     void incrementalResults();
     void noDetatch();
     void stlContainers();
+    void qFutureAssignmentLeak();
     void stressTest();
 public slots:
     void throttling();
@@ -2323,6 +2324,36 @@ void tst_map::stlContainers()
 #endif
 }
 
+InstanceCounter ic_fn(const InstanceCounter & ic)
+{
+    return InstanceCounter(ic);
+};
+
+// Verify that held results are deleted when a future is
+// assigned over with operator ==
+void tst_map::qFutureAssignmentLeak()
+{
+    currentInstanceCount = 0;
+    peakInstanceCount = 0;
+    QFuture<InstanceCounter> future;
+    {
+        QList<InstanceCounter> list;
+        for (int i=0;i<1000;++i)
+            list += InstanceCounter();
+        future = QtConcurrent::mapped(list, ic_fn);
+        future.waitForFinished();
+
+        future = QtConcurrent::mapped(list, ic_fn);
+        future.waitForFinished();
+
+        future = QtConcurrent::mapped(list, ic_fn);
+        future.waitForFinished();
+    }
+
+    QCOMPARE(int(currentInstanceCount), 1000);
+    future = QFuture<InstanceCounter>();
+    QCOMPARE(int(currentInstanceCount), 0);
+}
 
 inline void increment(int &num)
 {
-- 
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