runAsync: Remove ResultType template parameter.

It is now deduced from either the type of the
QFutureInterface<ResultType> function argument, or the return type.

Change-Id: Iddab3cc329206c649a6e55a44b2de2d406701dee
Reviewed-by: Tobias Hunger <tobias.hunger@theqtcompany.com>

src/libs/qmljs/qmljsmodelmanagerinterface.cpp

@@ -319,10 +319,10 @@ QFuture<void> ModelManagerInterface::refreshSourceFiles(const QStringList &sourc
     if (sourceFiles.isEmpty())
         return QFuture<void>();
 
-    QFuture<void> result = Utils::runAsync<void>(&ModelManagerInterface::parse,
-                                                 workingCopyInternal(), sourceFiles,
-                                                 this, Dialect(Dialect::Qml),
-                                                 emitDocumentOnDiskChanged);
+    QFuture<void> result = Utils::runAsync(&ModelManagerInterface::parse,
+                                           workingCopyInternal(), sourceFiles,
+                                           this, Dialect(Dialect::Qml),
+                                           emitDocumentOnDiskChanged);
     cleanupFutures();
     m_futures.append(result);
 
@@ -348,9 +348,9 @@ QFuture<void> ModelManagerInterface::refreshSourceFiles(const QStringList &sourc
 
 void ModelManagerInterface::fileChangedOnDisk(const QString &path)
 {
-    Utils::runAsync<void>(&ModelManagerInterface::parse,
-                          workingCopyInternal(), QStringList() << path,
-                          this, Dialect(Dialect::AnyLanguage), true);
+    Utils::runAsync(&ModelManagerInterface::parse,
+                    workingCopyInternal(), QStringList() << path,
+                    this, Dialect(Dialect::AnyLanguage), true);
 }
 
 void ModelManagerInterface::removeFiles(const QStringList &files)
@@ -1096,9 +1096,9 @@ void ModelManagerInterface::maybeScan(const PathsAndLanguages &importPaths)
     }
 
     if (pathToScan.length() > 1) {
-        QFuture<void> result = Utils::runAsync<void>(&ModelManagerInterface::importScan,
-                                                     workingCopyInternal(), pathToScan,
-                                                     this, true, true);
+        QFuture<void> result = Utils::runAsync(&ModelManagerInterface::importScan,
+                                               workingCopyInternal(), pathToScan,
+                                               this, true, true);
         cleanupFutures();
         m_futures.append(result);
 
@@ -1243,7 +1243,7 @@ void ModelManagerInterface::startCppQmlTypeUpdate()
     if (!cppModelManager)
         return;
 
-    m_cppQmlTypesUpdater = Utils::runAsync<void>(&ModelManagerInterface::updateCppQmlTypes,
+    m_cppQmlTypesUpdater = Utils::runAsync(&ModelManagerInterface::updateCppQmlTypes,
                 this, cppModelManager->snapshot(), m_queuedCppDocuments);
     m_queuedCppDocuments.clear();
 }

src/libs/utils/runextensions.h

@@ -435,6 +435,138 @@ QT_END_NAMESPACE
 namespace Utils {
 namespace Internal {
 
+/*
+   resultType<F>::type
+
+   Returns the type of results that would be reported by a callable of type F
+   when called through the runAsync methods. I.e. the ResultType in
+
+   void f(QFutureInterface<Result> &fi, ...)
+   ResultType f(...)
+
+   Returns void if F is not callable, and if F is a callable that does not take
+   a QFutureInterface& as its first parameter and returns void.
+*/
+
+template<typename T>
+struct hasCallOperator
+{
+    using yes = char;
+    using no = struct { char foo[2]; };
+
+    template<typename C>
+    static yes test(decltype(&C::operator()));
+
+    template<typename C>
+    static no test(...);
+
+    static const bool value = (sizeof(test<T>(0)) == sizeof(yes));
+};
+
+template <typename Function>
+struct resultType;
+
+template <typename Function, typename Arg>
+struct resultTypeWithArgument;
+
+template <typename Function, int index, bool>
+struct resultTypeTakesArguments;
+
+template <typename Function, bool>
+struct resultTypeIsMemberFunction;
+
+template <typename Function, bool>
+struct resultTypeIsFunctionLike;
+
+template <typename Function, bool>
+struct resultTypeHasCallOperator;
+
+template <typename Function, typename ResultType>
+struct resultTypeWithArgument<Function, QFutureInterface<ResultType>&>
+{
+    using type = ResultType;
+};
+
+template <typename Function, typename Arg>
+struct resultTypeWithArgument
+{
+    using type = typename functionTraits<Function>::ResultType;
+};
+
+template <typename Function, int index>
+struct resultTypeTakesArguments<Function, index, true>
+        : public resultTypeWithArgument<Function, typename functionTraits<Function>::template argument<index>::type>
+{
+};
+
+template <typename Function, int index>
+struct resultTypeTakesArguments<Function, index, false>
+{
+    using type = typename functionTraits<Function>::ResultType;
+};
+
+template <typename Function>
+struct resultTypeIsFunctionLike<Function, true>
+        : public resultTypeTakesArguments<Function, 0, (functionTraits<Function>::arity > 0)>
+{
+};
+
+template <typename Function>
+struct resultTypeIsMemberFunction<Function, true>
+        : public resultTypeTakesArguments<Function, 1, (functionTraits<Function>::arity > 1)>
+{
+};
+
+template <typename Function>
+struct resultTypeIsMemberFunction<Function, false>
+{
+    using type = void;
+};
+
+template <typename Function>
+struct resultTypeIsFunctionLike<Function, false>
+        : public resultTypeIsMemberFunction<Function, std::is_member_function_pointer<Function>::value>
+{
+};
+
+template <typename Function>
+struct resultTypeHasCallOperator<Function, false>
+        : public resultTypeIsFunctionLike<Function, std::is_function<typename std::remove_pointer<typename std::decay<Function>::type>::type>::value>
+{
+};
+
+template <typename Callable>
+struct resultTypeHasCallOperator<Callable, true>
+        : public resultTypeTakesArguments<decltype(&Callable::operator()), 1, (functionTraits<decltype(&Callable::operator())>::arity > 1)>
+{
+};
+
+template <typename Function>
+struct resultType
+        : public resultTypeHasCallOperator<Function, hasCallOperator<Function>::value>
+{
+};
+
+template <typename Function>
+struct resultType<Function&> : public resultType<Function>
+{
+};
+
+template <typename Function>
+struct resultType<const Function&> : public resultType<Function>
+{
+};
+
+template <typename Function>
+struct resultType<Function &&> : public resultType<Function>
+{
+};
+
+/*
+   Callable object that wraps a member function pointer with the object it
+   will be called on.
+*/
+
 template <typename Function>
 class MemberCallable;
 
@@ -478,6 +610,10 @@ private:
     Obj *m_obj;
 };
 
+/*
+   Helper functions for runAsync that run in the started thread.
+*/
+
 // void function that does not take QFutureInterface
 template <typename ResultType, typename Function, typename... Args>
 void runAsyncReturnVoidDispatch(std::true_type, QFutureInterface<ResultType> futureInterface, Function &&function, Args&&... args)
@@ -557,6 +693,11 @@ void runAsyncImpl(QFutureInterface<ResultType> futureInterface, Function &&funct
                  std::forward<Args>(args)...);
 }
 
+/*
+   AsyncJob is a QRunnable that wraps a function with the
+   arguments that are passed to it when it is run in a thread.
+*/
+
 // can be replaced with std::(make_)index_sequence with C++14
 template <std::size_t...>
 struct indexSequence { };
@@ -671,9 +812,10 @@ private:
     \sa QThreadPool
     \sa QThread::Priority
  */
-template <typename ResultType, typename Function, typename... Args>
-QFuture<ResultType> runAsync(QThreadPool *pool, QThread::Priority priority,
-                             Function &&function, Args&&... args)
+template <typename Function, typename... Args,
+          typename ResultType = typename Internal::resultType<Function>::type>
+QFuture<ResultType>
+runAsync(QThreadPool *pool, QThread::Priority priority, Function &&function, Args&&... args)
 {
     auto job = new Internal::AsyncJob<ResultType,Function,Args...>
             (std::forward<Function>(function), std::forward<Args>(args)...);
@@ -696,11 +838,13 @@ QFuture<ResultType> runAsync(QThreadPool *pool, QThread::Priority priority,
     \sa runAsync(QThreadPool*,QThread::Priority,Function&&,Args&&...)
     \sa QThread::Priority
  */
-template <typename ResultType, typename Function, typename... Args>
-QFuture<ResultType> runAsync(QThread::Priority priority, Function &&function, Args&&... args)
+template <typename Function, typename... Args,
+          typename ResultType = typename Internal::resultType<Function>::type>
+QFuture<ResultType>
+runAsync(QThread::Priority priority, Function &&function, Args&&... args)
 {
-    return runAsync<ResultType>(static_cast<QThreadPool *>(nullptr), priority,
-                                std::forward<Function>(function), std::forward<Args>(args)...);
+    return runAsync(static_cast<QThreadPool *>(nullptr), priority,
+                    std::forward<Function>(function), std::forward<Args>(args)...);
 }
 
 /*!
@@ -708,16 +852,18 @@ QFuture<ResultType> runAsync(QThread::Priority priority, Function &&function, Ar
     \sa runAsync(QThreadPool*,QThread::Priority,Function&&,Args&&...)
     \sa QThread::Priority
  */
-template <typename ResultType, typename Function, typename... Args,
+template <typename Function, typename... Args,
           typename = typename std::enable_if<
                 !std::is_same<typename std::decay<Function>::type, QThreadPool>::value
                 && !std::is_same<typename std::decay<Function>::type, QThread::Priority>::value
-              >::type>
-QFuture<ResultType> runAsync(Function &&function, Args&&... args)
-{
-    return runAsync<ResultType>(static_cast<QThreadPool *>(nullptr),
-                                QThread::InheritPriority, std::forward<Function>(function),
-                                std::forward<Args>(args)...);
+              >::type,
+          typename ResultType = typename Internal::resultType<Function>::type>
+QFuture<ResultType>
+runAsync(Function &&function, Args&&... args)
+{
+    return runAsync(static_cast<QThreadPool *>(nullptr),
+                    QThread::InheritPriority, std::forward<Function>(function),
+                    std::forward<Args>(args)...);
 }
 
 /*!
@@ -725,15 +871,16 @@ QFuture<ResultType> runAsync(Function &&function, Args&&... args)
     \sa runAsync(QThreadPool*,QThread::Priority,Function&&,Args&&...)
     \sa QThread::Priority
  */
-template <typename ResultType, typename Function, typename... Args,
+template <typename Function, typename... Args,
           typename = typename std::enable_if<
                 !std::is_same<typename std::decay<Function>::type, QThread::Priority>::value
-              >::type>
-QFuture<ResultType> runAsync(QThreadPool *pool,
-                             Function &&function, Args&&... args)
+              >::type,
+          typename ResultType = typename Internal::resultType<Function>::type>
+QFuture<ResultType>
+runAsync(QThreadPool *pool, Function &&function, Args&&... args)
 {
-    return runAsync<ResultType>(pool, QThread::InheritPriority, std::forward<Function>(function),
-                                std::forward<Args>(args)...);
+    return runAsync(pool, QThread::InheritPriority, std::forward<Function>(function),
+                    std::forward<Args>(args)...);
 }
 
 } // Utils

src/libs/utils/shellcommand.cpp

@@ -222,7 +222,7 @@ void ShellCommand::execute()
     if (d->m_jobs.empty())
         return;
 
-    QFuture<void> task = Utils::runAsync<void>(&ShellCommand::run, this);
+    QFuture<void> task = Utils::runAsync(&ShellCommand::run, this);
     d->m_watcher.setFuture(task);
     addTask(task);
 }

src/plugins/autotest/testcodeparser.cpp

@@ -738,7 +738,7 @@ void TestCodeParser::scanForTests(const QStringList &fileList)
     }
 
     QFuture<TestParseResult> future
-            = Utils::runAsync<TestParseResult>(&performParse, list, referencingFiles);
+            = Utils::runAsync(&performParse, list, referencingFiles);
     m_futureWatcher.setFuture(future);
     if (list.size() > 5) {
         Core::ProgressManager::addTask(future, tr("Scanning for Tests"),

src/plugins/autotest/testrunner.cpp

@@ -285,8 +285,8 @@ void TestRunner::runTests()
     const QSharedPointer<TestSettings> settings = AutotestPlugin::instance()->settings();
     const QString &metricsOption = TestSettings::metricsTypeToOption(settings->metrics);
 
-    QFuture<TestResult *> future = Utils::runAsync<TestResult *>(&performTestRun, m_selectedTests,
-                                                               settings->timeout, metricsOption);
+    QFuture<TestResult *> future = Utils::runAsync(&performTestRun, m_selectedTests,
+                                                   settings->timeout, metricsOption);
     m_futureWatcher.setFuture(future);
     Core::ProgressManager::addTask(future, tr("Running Tests"), Autotest::Constants::TASK_INDEX);
 }

src/plugins/coreplugin/locator/locatorfiltertest.cpp

@@ -45,9 +45,8 @@ QList<LocatorFilterEntry> BasicLocatorFilterTest::matchesFor(const QString &sear
     doBeforeLocatorRun();
     const QList<ILocatorFilter *> filters = QList<ILocatorFilter *>() << m_filter;
     m_filter->prepareSearch(searchText);
-    QFuture<LocatorFilterEntry> locatorSearch = Utils::runAsync<LocatorFilterEntry>(&Internal::runSearch,
-                                                                                    filters,
-                                                                                    searchText);
+    QFuture<LocatorFilterEntry> locatorSearch = Utils::runAsync(&Internal::runSearch, filters,
+                                                                searchText);
     locatorSearch.waitForFinished();
     doAfterLocatorRun();
     return locatorSearch.results();

src/plugins/coreplugin/locator/locatorwidget.cpp

@@ -520,8 +520,7 @@ void LocatorWidget::updateCompletionList(const QString &text)
 
     foreach (ILocatorFilter *filter, filters)
         filter->prepareSearch(searchText);
-    QFuture<LocatorFilterEntry> future = Utils::runAsync<LocatorFilterEntry>(&runSearch, filters,
-                                                                             searchText);
+    QFuture<LocatorFilterEntry> future = Utils::runAsync(&runSearch, filters, searchText);
     m_entriesWatcher->setFuture(future);
 }
 

src/plugins/git/gitgrep.cpp

@@ -235,7 +235,7 @@ void GitGrep::writeSettings(QSettings *settings) const
 QFuture<FileSearchResultList> GitGrep::executeSearch(
         const TextEditor::FileFindParameters &parameters)
 {
-    return Utils::runAsync<FileSearchResultList>(GitGrepRunner::run, parameters);
+    return Utils::runAsync(GitGrepRunner::run, parameters);
 }
 
 } // Internal

src/plugins/qmakeprojectmanager/qmakenodes.cpp

@@ -1806,10 +1806,10 @@ void QmakeProFileNode::asyncUpdate()
         m_readerExact->setExact(false);
     m_parseFutureWatcher.waitForFinished();
     EvalInput input = evalInput();
-    QFuture<EvalResult *> future = Utils::runAsync<EvalResult *>(ProjectExplorerPlugin::sharedThreadPool(),
-                                                                 QThread::LowestPriority,
-                                                                 &QmakeProFileNode::asyncEvaluate,
-                                                                 this, input);
+    QFuture<EvalResult *> future = Utils::runAsync(ProjectExplorerPlugin::sharedThreadPool(),
+                                                   QThread::LowestPriority,
+                                                   &QmakeProFileNode::asyncEvaluate,
+                                                   this, input);
     m_parseFutureWatcher.setFuture(future);
 }
 

src/plugins/qmljseditor/qmljsfindreferences.cpp

@@ -891,10 +891,8 @@ void FindReferences::findUsages(const QString &fileName, quint32 offset)
 {
     ModelManagerInterface *modelManager = ModelManagerInterface::instance();
 
-    QFuture<Usage> result = Utils::runAsync<Usage>(
-                &find_helper, modelManager->workingCopy(),
-                modelManager->snapshot(), fileName, offset,
-                QString());
+    QFuture<Usage> result = Utils::runAsync(&find_helper, modelManager->workingCopy(),
+                                            modelManager->snapshot(), fileName, offset, QString());
     m_watcher.setFuture(result);
 }
 
@@ -908,10 +906,8 @@ void FindReferences::renameUsages(const QString &fileName, quint32 offset,
     if (newName.isNull())
         newName = QLatin1String("");
 
-    QFuture<Usage> result = Utils::runAsync<Usage>(
-                &find_helper, modelManager->workingCopy(),
-                modelManager->snapshot(), fileName, offset,
-                newName);
+    QFuture<Usage> result = Utils::runAsync(&find_helper, modelManager->workingCopy(),
+                                            modelManager->snapshot(), fileName, offset, newName);
     m_watcher.setFuture(result);
 }
 

src/plugins/qmljseditor/qmljssemantichighlighter.cpp

@@ -545,8 +545,8 @@ void SemanticHighlighter::rerun(const QmlJSTools::SemanticInfo &semanticInfo)
     m_watcher.cancel();
 
     m_startRevision = m_document->document()->revision();
-    m_watcher.setFuture(Utils::runAsync<Use>(QThread::LowestPriority,
-                                             &SemanticHighlighter::run, this, semanticInfo));
+    m_watcher.setFuture(Utils::runAsync(QThread::LowestPriority,
+                                        &SemanticHighlighter::run, this, semanticInfo));
 }
 
 void SemanticHighlighter::cancel()

src/plugins/qmljseditor/qmltaskmanager.cpp

@@ -152,7 +152,7 @@ void QmlTaskManager::updateMessagesNow(bool updateSemantic)
 
     // process them
     QFuture<FileErrorMessages> future =
-            Utils::runAsync<FileErrorMessages>(
+            Utils::runAsync(
                 &collectMessages, modelManager->newestSnapshot(), modelManager->projectInfos(),
                 modelManager->defaultVContext(Dialect::AnyLanguage), updateSemantic);
     m_messageCollector.setFuture(future);

src/plugins/qmlprofiler/qmlprofilermodelmanager.cpp

@@ -347,7 +347,7 @@ void QmlProfilerModelManager::save(const QString &filename)
     connect(writer, &QObject::destroyed, this, &QmlProfilerModelManager::saveFinished,
             Qt::QueuedConnection);
 
-    QFuture<void> result = Utils::runAsync<void>([file, writer] (QFutureInterface<void> &future) {
+    QFuture<void> result = Utils::runAsync([file, writer] (QFutureInterface<void> &future) {
         writer->setFuture(&future);
         writer->save(file);
         delete writer;
@@ -387,7 +387,7 @@ void QmlProfilerModelManager::load(const QString &filename)
         acquiringDone();
     }, Qt::QueuedConnection);
 
-    QFuture<void> result = Utils::runAsync<void>([file, reader] (QFutureInterface<void> &future) {
+    QFuture<void> result = Utils::runAsync([file, reader] (QFutureInterface<void> &future) {
         reader->setFuture(&future);
         reader->load(file);
         file->close();

src/plugins/texteditor/generichighlighter/manager.cpp

@@ -322,7 +322,7 @@ void Manager::registerHighlightingFiles()
     if (!m_registeringWatcher.isRunning()) {
         clear();
 
-        QFuture<RegisterData> future = Utils::runAsync<RegisterData>(ManagerProcessor());
+        QFuture<RegisterData> future = Utils::runAsync(ManagerProcessor());
         m_registeringWatcher.setFuture(future);
     } else {
         m_hasQueuedRegistration = true;

src/plugins/vcsbase/cleandialog.cpp

@@ -250,8 +250,8 @@ bool CleanDialog::promptToDelete()
         return false;
 
     // Remove in background
-    QFuture<void> task = Utils::runAsync<void>(Internal::runCleanFiles, d->m_workingDirectory,
-                                               selectedFiles, Internal::handleError);
+    QFuture<void> task = Utils::runAsync(Internal::runCleanFiles, d->m_workingDirectory,
+                                         selectedFiles, Internal::handleError);
 
     const QString taskName = tr("Cleaning \"%1\"").
                              arg(QDir::toNativeSeparators(d->m_workingDirectory));