Temporarily disable QFuture::takeResult() method

QFuture::takeResult() currently returns std::vector instead of QList,
because QList does not support move-only types. Disable this method
until QList is fixed to work with move-only types in Qt 6.1.

Also did minor doc-fixes.

Change-Id: I87feaf75d9433a3b540edd00039c3e21d6994985
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

src/corelib/thread/qfuture.h

@@ -163,8 +163,11 @@ QT_WARNING_POP
     template<typename U = T, typename = QtPrivate::EnableForNonVoid<U>>
     T takeResult() { return d.takeResult(); }
 
+#if 0
+    // TODO: Enable and make it return a QList, when QList is fixed to support move-only types
     template<typename U = T, typename = QtPrivate::EnableForNonVoid<U>>
     std::vector<T> takeResults() { return d.takeResults(); }
+#endif
 
     bool isValid() const { return d.isValid(); }
 

src/corelib/thread/qfuture.qdoc

@@ -39,15 +39,14 @@
     which will be ready at a later point in time. The result can be of any type
     that has default, copy and possibly move constructors. If
     a result is not available at the time of calling the result(), resultAt(),
-    results(), takeResult(), or takeResults() functions, QFuture
+    results() and takeResult() functions, QFuture will wait until the result
-    will wait until the result becomes available. You can use the isResultReadyAt()
+    becomes available. You can use the isResultReadyAt() function to determine
-    function to determine if a result is ready or not. For QFuture objects that
+    if a result is ready or not. For QFuture objects that report more than one
-    report more than one result, the resultCount() function returns the number
+    result, the resultCount() function returns the number of continuous results.
-    of continuous results. This means that it is always safe to iterate through
+    This means that it is always safe to iterate through the results from 0 to
-    the results from 0 to resultCount(). takeResult() and takeResults()
+    resultCount(). takeResult() invalidates a future, and any subsequent attempt
-    invalidate a future and any subsequent attempt to access result or results
+    to access result or results from the future leads to undefined behavior.
-    from the future leads to undefined behavior. isValid() tells you if
+    isValid() tells you if results can be accessed.
-    results can be accessed.
 
     QFuture provides a \l{Java-style iterators}{Java-style iterator}
     (QFutureIterator) and an \l{STL-style iterators}{STL-style iterator}
@@ -367,7 +366,7 @@
     number of results stored might be different from this value, due to gaps
     in the result set. It is always safe to iterate through the results from 0
     to resultCount().
-    \sa result(), resultAt(), results(), takeResult(), takeResults()
+    \sa result(), resultAt(), results(), takeResult()
 */
 
 /*! \fn template <typename T> int QFuture<T>::progressValue() const
@@ -419,7 +418,7 @@
     \note Calling \c result() leads to undefined behavior if isValid()
     returns \c false for this QFuture.
 
-    \sa resultAt(), results(), takeResult(), takeResults()
+    \sa resultAt(), results(), takeResult()
 */
 
 /*! \fn template <typename T> T QFuture<T>::resultAt(int index) const
@@ -431,7 +430,7 @@
     \note Calling resultAt() leads to undefined behavior if isValid()
     returns \c false for this QFuture.
 
-    \sa result(), results(), takeResult(), takeResults(), resultCount()
+    \sa result(), results(), takeResult(), resultCount()
 */
 
 /*! \fn template <typename T> bool QFuture<T>::isResultReadyAt(int index) const
@@ -442,7 +441,7 @@
     \note Calling isResultReadyAt() leads to undefined behavior if isValid()
     returns \c false for this QFuture.
 
-    \sa resultAt(), resultCount(), takeResult(), takeResults()
+    \sa resultAt(), resultCount(), takeResult()
 */
 
 /*! \fn template <typename T> QFuture<T>::operator T() const
@@ -455,23 +454,25 @@
     \note Calling this function leads to undefined behavior if isValid()
     returns \c false for this QFuture.
 
-    \sa result(), resultAt(), results(), takeResult(), takeResults(), isValid()
+    \sa result(), resultAt(), results(), takeResult(), isValid()
 */
 
 /*! \fn template <typename T> QList<T> QFuture<T>::results() const
 
     Returns all results from the future. If the results are not immediately available,
     this function will block and wait for them to become available. Note that
-    \c results() returns a copy of the internally stored results. If \c T is a
+    \c results() returns a copy of the internally stored results. Getting all
-    move-only type, or you don't want to copy the results, use takeResults()
+    results of a move-only type \c T is not supported at the moment. However you can
-    instead.
+    still iterate through the list of move-only results by using \l{STL-style iterators}
+    or read-only \l{Java-style iterators}.
 
     \note Calling \c results() leads to undefined behavior if isValid()
     returns \c false for this QFuture.
 
-    \sa result(), resultAt(), takeResult(), takeResults(), resultCount(), isValid()
+    \sa result(), resultAt(), takeResult(), resultCount(), isValid()
 */
 
+#if 0
 /*! \fn template <typename T> std::vector<T> QFuture<T>::takeResults()
 
     If isValid() returns \c false, calling this function leads to undefined behavior.
@@ -489,14 +490,16 @@
 
     \sa takeResult(), result(), resultAt(), results(), resultCount(), isValid()
 */
+#endif
 
 /*! \fn template <typename T> std::vector<T> QFuture<T>::takeResult()
 
+    \since 6.0
+
     Call this function only if isValid() returns \c true, otherwise
-    the behavior is undefined. This function takes the first result from
+    the behavior is undefined. This function takes (moves) the first result from
-    the QFuture object, for convenience when only one result is expected.
+    the QFuture object, when only one result is expected. If there are any other
-    If there are any other results, they are discarded after taking the
+    results, they are discarded after taking the first one.
-    first one (if such behavior is undesired, use takeResults() instead).
     If the result is not immediately available, this function will block and
     wait for the result to become available. The QFuture will try to use move
     semantics if possible, and will fall back to copy construction if the type
@@ -507,17 +510,21 @@
     objects (and potentially between different threads). takeResult() was introduced
     to make QFuture also work with move-only types (like std::unique_ptr), so it
     assumes that only one thread can move the results out of the future, and
-    do it only once.
+    do it only once. Also note that taking the list of all results is not supported
+    at the moment. However you can still iterate through the list of move-only
+    results by using \l{STL-style iterators} or read-only \l{Java-style iterators}.
 
-    \sa takeResults(), result(), results(), resultAt(), isValid()
+    \sa result(), results(), resultAt(), isValid()
 */
 
 /*! \fn template <typename T> bool QFuture<T>::isValid() const
 
+    \since 6.0
+
     Returns \c true if a result or results can be accessed or taken from this
     QFuture object. Returns false after the result was taken from the future.
 
-    \sa takeResults(), takeResult(), result(), results(), resultAt()
+    \sa takeResult(), result(), results(), resultAt()
 */
 
 /*! \fn template <typename T> QFuture<T>::const_iterator QFuture<T>::begin() const

src/corelib/thread/qfutureinterface.h

@@ -252,7 +252,10 @@ public:
     inline QList<T> results();
 
     T takeResult();
+#if 0
+    // TODO: Enable and make it return a QList, when QList is fixed to support move-only types
     std::vector<T> takeResults();
+#endif
 };
 
 template <typename T>
@@ -384,6 +387,7 @@ T QFutureInterface<T>::takeResult()
     return ret;
 }
 
+#if 0
 template<typename T>
 std::vector<T> QFutureInterface<T>::takeResults()
 {
@@ -404,6 +408,7 @@ std::vector<T> QFutureInterface<T>::takeResults()
 
     return res;
 }
+#endif
 
 template <>
 class QFutureInterface<void> : public QFutureInterfaceBase

tests/auto/corelib/thread/qfuture/tst_qfuture.cpp

@@ -136,7 +136,10 @@ private slots:
     void onFailedForMoveOnlyTypes();
 #endif
     void onCanceled();
+#if 0
+    // TODO: enable when QFuture::takeResults() is enabled
     void takeResults();
+#endif
     void takeResult();
     void runAndTake();
     void resultsReadyAt_data();
@@ -2829,6 +2832,7 @@ void tst_QFuture::testTakeResults(QFuture<T> future, size_type resultCount)
     testFutureTaken(copy);
 }
 
+#if 0
 void tst_QFuture::takeResults()
 {
     // Test takeResults() for movable types (whether or not copyable).
@@ -2857,6 +2861,7 @@ void tst_QFuture::takeResults()
 
     testTakeResults(copyIface.future(), size_type(expectedCount));
 }
+#endif
 
 void tst_QFuture::takeResult()
 {
@@ -2903,7 +2908,10 @@ void tst_QFuture::runAndTake()
         QSKIP("Failed to run the task, nothing to test");
 
     gotcha = watcha.future();
+#if 0
+    // TODO: enable when QFuture::takeResults() is enabled
     testTakeResults(gotcha, size_type(1));
+#endif
 }
 
 void tst_QFuture::resultsReadyAt_data()