QtConcurrent: Get rid of multi-inheritance inside RunFunctionTaskBase

Use aggregation instead. Prepare for using QPromise instead of QFutureInterface.

Task-number: QTBUG-84702
Change-Id: Ic88564dca8c83a178a281cb843032292210a6d25
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>

2 files changed, 23 insertions, 21 deletions

diff --git a/src/concurrent/qtconcurrentrunbase.h b/src/concurrent/qtconcurrentrunbase.h
index 176097c04f..c748d8e2b9 100644
--- a/src/concurrent/qtconcurrentrunbase.h
+++ b/src/concurrent/qtconcurrentrunbase.h
@@ -79,7 +79,7 @@ struct TaskStartParameters
 };
 
 template <typename T>
-class RunFunctionTaskBase : public QFutureInterface<T> , public QRunnable
+class RunFunctionTaskBase : public QRunnable
 {
 public:
     QFuture<T> start()
@@ -89,10 +89,10 @@ public:
 
     QFuture<T> start(const TaskStartParameters &parameters)
     {
-        this->setThreadPool(parameters.threadPool);
-        this->setRunnable(this);
-        this->reportStarted();
-        QFuture<T> theFuture = this->future();
+        promise.setThreadPool(parameters.threadPool);
+        promise.setRunnable(this);
+        promise.reportStarted();
+        QFuture<T> theFuture = promise.future();
         parameters.threadPool->start(this, parameters.priority);
         return theFuture;
     }
@@ -102,8 +102,8 @@ public:
 
     void run() override
     {
-        if (this->isCanceled()) {
-            this->reportFinished();
+        if (promise.isCanceled()) {
+            promise.reportFinished();
             return;
         }
 #ifndef QT_NO_EXCEPTIONS
@@ -112,20 +112,22 @@ public:
             runFunctor();
 #ifndef QT_NO_EXCEPTIONS
         } catch (QException &e) {
-            QFutureInterface<T>::reportException(e);
+            promise.reportException(e);
         } catch (...) {
-            QFutureInterface<T>::reportException(QUnhandledException());
+            promise.reportException(QUnhandledException());
         }
 #endif
 
         reportResult();
 
-        this->reportFinished();
+        promise.reportFinished();
     }
 
 protected:
     virtual void runFunctor() = 0;
     virtual void reportResult() {}
+
+    QFutureInterface<T> promise;
 };
 
 template <typename T>
@@ -135,9 +137,9 @@ protected:
     void reportResult() override
     {
         if constexpr (std::is_move_constructible_v<T>)
-            this->reportAndMoveResult(std::move(result));
+            this->promise.reportAndMoveResult(std::move(result));
         else if constexpr (std::is_copy_constructible_v<T>)
-            this->reportResult(result);
+            this->promise.reportResult(result);
     }
 
     T result;
diff --git a/tests/auto/corelib/thread/qfuturewatcher/tst_qfuturewatcher.cpp b/tests/auto/corelib/thread/qfuturewatcher/tst_qfuturewatcher.cpp
index d4f609874e..63277b02df 100644
--- a/tests/auto/corelib/thread/qfuturewatcher/tst_qfuturewatcher.cpp
+++ b/tests/auto/corelib/thread/qfuturewatcher/tst_qfuturewatcher.cpp
@@ -457,9 +457,9 @@ class ProgressEmitterTask : public RunFunctionTask<void>
 public:
     void runFunctor()
     {
-        setProgressRange(0, maxProgress);
+        promise.setProgressRange(0, maxProgress);
         for (int p = 0; p <= maxProgress; ++p)
-            setProgressValue(p);
+            promise.setProgressValue(p);
     }
 };
 
@@ -487,19 +487,19 @@ class ProgressTextTask : public RunFunctionTask<T>
 public:
     void runFunctor()
     {
-        this->setProgressValueAndText(1, QLatin1String("Foo 1"));
+        this->promise.setProgressValueAndText(1, QLatin1String("Foo 1"));
 
-        while (this->isProgressUpdateNeeded() == false)
+        while (this->promise.isProgressUpdateNeeded() == false)
             QTest::qSleep(1);
-        this->setProgressValueAndText(2, QLatin1String("Foo 2"));
+        this->promise.setProgressValueAndText(2, QLatin1String("Foo 2"));
 
-        while (this->isProgressUpdateNeeded() == false)
+        while (this->promise.isProgressUpdateNeeded() == false)
             QTest::qSleep(1);
-        this->setProgressValueAndText(3, QLatin1String("Foo 3"));
+        this->promise.setProgressValueAndText(3, QLatin1String("Foo 3"));
 
-        while (this->isProgressUpdateNeeded() == false)
+        while (this->promise.isProgressUpdateNeeded() == false)
             QTest::qSleep(1);
-        this->setProgressValueAndText(4, QLatin1String("Foo 4"));
+        this->promise.setProgressValueAndText(4, QLatin1String("Foo 4"));
     }
 };