1 files changed, 17 insertions, 5 deletions
diff --git a/src/concurrent/qtconcurrentreducekernel.h b/src/concurrent/qtconcurrentreducekernel.h
index 9ea0f33f91..c337a9192f 100644
--- a/src/concurrent/qtconcurrentreducekernel.h
+++ b/src/concurrent/qtconcurrentreducekernel.h
@@ -5,9 +5,8 @@
 #define QTCONCURRENT_REDUCEKERNEL_H
 
 #include <QtConcurrent/qtconcurrent_global.h>
-#include <QtConcurrent/qtconcurrentfunctionwrappers.h>
 
-#if !defined(QT_NO_CONCURRENT) || defined(Q_CLANG_QDOC)
+#if !defined(QT_NO_CONCURRENT) || defined(Q_QDOC)
 
 #include <QtCore/qatomic.h>
 #include <QtCore/qlist.h>
@@ -20,6 +19,17 @@
 
 QT_BEGIN_NAMESPACE
 
+namespace QtPrivate {
+
+template<typename Sequence>
+struct SequenceHolder
+{
+    SequenceHolder(const Sequence &s) : sequence(s) { }
+    SequenceHolder(Sequence &&s) : sequence(std::move(s)) { }
+    Sequence sequence;
+};
+
+}
 
 namespace QtConcurrent {
 
@@ -30,7 +40,7 @@ namespace QtConcurrent {
     MapReduce won't start any new threads, and when it exceeds
     ReduceQueueThrottleLimit running threads will be stopped.
 */
-#ifdef Q_CLANG_QDOC
+#ifdef Q_QDOC
 enum ReduceQueueLimits {
     ReduceQueueStartLimit = 20,
     ReduceQueueThrottleLimit = 30
@@ -60,7 +70,7 @@ enum ReduceOption {
     // ParallelReduce = 0x8
 };
 Q_DECLARE_FLAGS(ReduceOptions, ReduceOption)
-#ifndef Q_CLANG_QDOC
+#ifndef Q_QDOC
 Q_DECLARE_OPERATORS_FOR_FLAGS(ReduceOptions)
 #endif
 // supports both ordered and out-of-order reduction
@@ -107,7 +117,7 @@ class ReduceKernel
 public:
     ReduceKernel(QThreadPool *pool, ReduceOptions _reduceOptions)
         : reduceOptions(_reduceOptions), progress(0), resultsMapSize(0),
-          threadCount(pool->maxThreadCount())
+          threadCount(std::max(pool->maxThreadCount(), 1))
     { }
 
     void runReduce(ReduceFunctor &reduce,
@@ -177,11 +187,13 @@ public:
 
     inline bool shouldThrottle()
     {
+        std::lock_guard<QMutex> locker(mutex);
         return (resultsMapSize > (ReduceQueueThrottleLimit * threadCount));
     }
 
     inline bool shouldStartThread()
     {
+        std::lock_guard<QMutex> locker(mutex);
         return (resultsMapSize <= (ReduceQueueStartLimit * threadCount));
     }
 };