TaskTree: Introduce For element

Improve code readability by requiring iteratable Group
to be named For.

The For's c'tor requires an iterator element as a first arg.

The For's c'tor allows for passing exactly one iterator element.

It's not possible to place iterators inside Group element anymore.

Change-Id: I9dfe2c0da058abac161f66c4e336da2417c383f1
Reviewed-by: hjk <hjk@qt.io>

src/libs/solutions/tasking/tasktree.h

@@ -207,13 +207,12 @@ public:
         : m_type(Type::Storage)
         , m_storageList{storage} {}
 
-    GroupItem(const Loop &loop) : GroupItem(GroupData{{}, {}, {}, loop}) {}
-
     // TODO: Add tests.
     GroupItem(const QList<GroupItem> &children) : m_type(Type::List) { addChildren(children); }
     GroupItem(std::initializer_list<GroupItem> children) : m_type(Type::List) { addChildren(children); }
 
 protected:
+    GroupItem(const Loop &loop) : GroupItem(GroupData{{}, {}, {}, loop}) {}
     // Internal, provided by CustomTask
     using InterfaceCreateHandler = std::function<TaskInterface *(void)>;
     // Called prior to task start, just after createHandler
@@ -274,6 +273,7 @@ protected:
 
 private:
     friend class ContainerNode;
+    friend class For;
     friend class TaskNode;
     friend class TaskTreePrivate;
     friend class ParallelLimitFunctor;
@@ -433,11 +433,42 @@ TASKING_EXPORT extern const GroupItem nullItem;
 TASKING_EXPORT extern const ExecutableItem successItem;
 TASKING_EXPORT extern const ExecutableItem errorItem;
 
-class TASKING_EXPORT Forever final : public Group
+class TASKING_EXPORT For : public Group
 {
 public:
-    Forever(const QList<GroupItem> &children) : Group({LoopForever(), children}) {}
+    template <typename ...Args>
-    Forever(std::initializer_list<GroupItem> children) : Group({LoopForever(), children}) {}
+    For(const Loop &loop, const Args &...args)
+        : Group(withLoop(loop, args...)) { }
+
+protected:
+    For(const Loop &loop, const QList<GroupItem> &children) : Group({loop, children}) {}
+    For(const Loop &loop, std::initializer_list<GroupItem> children) : Group({loop, children}) {}
+
+private:
+    template <typename ...Args>
+    QList<GroupItem> withLoop(const Loop &loop, const Args &...args) {
+        QList<GroupItem> children{GroupItem(loop)};
+        appendChildren(std::make_tuple(args...), &children);
+        return children;
+    }
+
+    template <typename Tuple, std::size_t N = 0>
+    void appendChildren(const Tuple &tuple, QList<GroupItem> *children) {
+        constexpr auto TupleSize = std::tuple_size_v<Tuple>;
+        if constexpr (TupleSize > 0) {
+            // static_assert(workflowPolicyCount<Tuple>() <= 1, "Too many workflow policies in one group.");
+            children->append(std::get<N>(tuple));
+            if constexpr (N + 1 < TupleSize)
+                appendChildren<Tuple, N + 1>(tuple, children);
+        }
+    }
+};
+
+class TASKING_EXPORT Forever final : public For
+{
+public:
+    Forever(const QList<GroupItem> &children) : For(LoopForever(), children) {}
+    Forever(std::initializer_list<GroupItem> children) : For(LoopForever(), children) {}
 };
 
 // Synchronous invocation. Similarly to Group - isn't counted as a task inside taskCount()

src/plugins/android/androiddevice.cpp

@@ -830,9 +830,9 @@ AndroidDeviceManagerInstance::AndroidDeviceManagerInstance(QObject *parent)
     // otherwise, Android Studio would give an error during parsing also. So this fix
     // aim to keep support for Qt Creator and Android Studio.
 
-    m_avdListRecipe = Group {
+    m_avdListRecipe = For {
-        storage,
         iterator,
+        storage,
         ProcessTask(onProcessSetup, onProcessDone)
     };
 }

src/plugins/android/androidqmlpreviewworker.cpp

@@ -179,20 +179,19 @@ void AndroidQmlPreviewWorker::startPidWatcher()
 
     const TimeoutTask timeout([](std::chrono::milliseconds &timeout) { timeout = 2s; });
 
-    const Group root {
+    const Group recipe {
-        Group {
+        For {
             pidIterator,
             ProcessTask(onPidSetup, onPidDone, CallDoneIf::Success),
             timeout
         }.withTimeout(20s),
-        Group {
+        For {
             alivePidIterator,
             ProcessTask(onPidSetup, onAlivePidDone),
             timeout
         }
     };
-
+    m_pidRunner.start(recipe);
-    m_pidRunner.start(root);
 }
 
 void AndroidQmlPreviewWorker::startLogcat()

src/plugins/android/androidsdkmanager.cpp

@@ -294,14 +294,14 @@ static GroupItem installationRecipe(const Storage<DialogStorage> &dialogStorage,
 
     return Group {
         onGroupSetup(onSetup),
-        Group {
+        For {
-            finishAllAndSuccess,
             uninstallIterator,
+            finishAllAndSuccess,
             ProcessTask(onUninstallSetup, onDone)
         },
-        Group {
+        For {
-            finishAllAndSuccess,
             installIterator,
+            finishAllAndSuccess,
             ProcessTask(onInstallSetup, onDone)
         }
     };

src/plugins/autotest/testcodeparser.cpp

@@ -417,14 +417,14 @@ void TestCodeParser::scanForTests(const QSet<FilePath> &filePaths,
         if (!results.isEmpty())
             emit testParseResultsReady(results);
     };
-    const Group root {
+    const For recipe {
+        LoopRepeat(filteredFiles.size()),
         parallelLimit(limit),
         storage,
         onGroupSetup([storage, filteredFiles] { *storage = filteredFiles.cbegin(); }),
-        LoopRepeat(filteredFiles.size()),
         AsyncTask<TestParseResultPtr>(onSetup, onDone, CallDoneIf::Success)
     };
-    m_taskTreeRunner.start(root);
+    m_taskTreeRunner.start(recipe);
 }
 
 void TestCodeParser::onTaskStarted(Id type)

src/plugins/autotest/testrunner.cpp

@@ -459,15 +459,15 @@ void TestRunner::runTestsHelper()
         }
     };
 
-    const Group root {
+    const For recipe {
-        finishAllAndSuccess,
         iterator,
+        finishAllAndSuccess,
         Group {
             storage,
             ProcessTask(onSetup, onDone)
         }
     };
-    m_taskTreeRunner.start(root);
+    m_taskTreeRunner.start(recipe);
 }
 
 static void processOutput(TestOutputReader *outputreader, const QString &msg, OutputFormat format)

src/plugins/axivion/axivionplugin.cpp

@@ -691,7 +691,7 @@ static Group authorizationRecipe()
                 *serverUrlStorage = unauthorizedDashboardStorage->url;
             }),
         },
-        Group {
+        For {
             LoopUntil(onCredentialLoopCondition),
             CredentialQueryTask(onGetCredentialSetup, onGetCredentialDone),
             Group {

src/plugins/clangtools/clangtoolrunner.cpp

@@ -224,10 +224,10 @@ GroupItem clangToolTask(const AnalyzeUnits &units,
                        error});
     };
 
-    return Group {
+    return For {
+        iterator,
         parallelLimit(qMax(1, input.runSettings.parallelJobs())),
         finishAllAndSuccess,
-        iterator,
         Group {
             storage,
             onGroupSetup(onSetup),

src/plugins/coreplugin/locator/ilocatorfilter.cpp

@@ -383,9 +383,9 @@ void LocatorMatcher::start()
         parallel,
         collectorStorage,
         AsyncTask<LocatorFilterEntries>(onCollectorSetup, onCollectorDone),
-        Group {
+        For {
-            parallelLimit(d->m_parallelLimit),
             iterator,
+            parallelLimit(d->m_parallelLimit),
             TaskTreeTask(onTaskTreeSetup)
         }
     };

src/plugins/diffeditor/diffeditorplugin.cpp

@@ -142,16 +142,16 @@ DiffFilesController::DiffFilesController(IDocument *document)
         setDiffFiles(finalList);
     };
 
-    const Group root {
+    const For recipe {
+        iterator,
         parallelIdealThreadCountLimit,
         finishAllAndSuccess,
         storage,
-        iterator,
         onGroupSetup(onSetup),
         AsyncTask<FileData>(onDiffSetup, onDiffDone, CallDoneIf::Success),
         onGroupDone(onDone)
     };
-    setReloadRecipe(root);
+    setReloadRecipe(recipe);
 }
 
 class DiffCurrentFileController : public DiffFilesController

src/plugins/git/gitclient.cpp

@@ -506,10 +506,10 @@ ShowController::ShowController(IDocument *document, const QString &id)
             updateDescription(*data);
         };
 
-        const Group recipe {
+        const For recipe {
+            iterator,
             parallel,
             continueOnSuccess,
-            iterator,
             ProcessTask(onFollowSetup, onFollowDone, CallDoneIf::Success),
             onGroupDone(onDone, CallDoneIf::Error)
         };

src/plugins/lua/bindings/install.cpp

@@ -196,10 +196,10 @@ static Group installRecipe(
         return DoneResult::Success;
     };
 
-    return Group{
+    return For {
+        installOptionsIt,
         storage,
         parallelIdealThreadCountLimit,
-        installOptionsIt,
         Group{
             onGroupSetup([emitResult, storage, installOptionsIt] {
                 const QString fileName = installOptionsIt->url.fileName();

src/plugins/projectexplorer/treescanner.cpp

@@ -237,12 +237,12 @@ static QList<FileNode *> scanForFilesHelper(
             }
         };
 
-        const Group group{
+        const For recipe {
-            Utils::HostOsInfo::isLinuxHost() ? parallelLimit(2) : parallelIdealThreadCountLimit,
             iterator,
+            Utils::HostOsInfo::isLinuxHost() ? parallelLimit(2) : parallelIdealThreadCountLimit,
             Utils::AsyncTask<DirectoryScanResult>(onSetup, onDone)
         };
-        TaskTree::runBlocking(group);
+        TaskTree::runBlocking(recipe);
     }
     return fileNodes;
 }

src/plugins/remotelinux/linuxdevice.cpp

@@ -1679,21 +1679,21 @@ private:
             }
         };
 
-        const Group group{
+        const Group recipe {
-            Group{
+            For {
-                parallelIdealThreadCountLimit,
                 iteratorParentDirs,
+                parallelIdealThreadCountLimit,
                 AsyncTask<expected_str<void>>(onCreateDirSetup, onCreateDirDone),
             },
-            Group{
+            For {
-                parallelLimit(2),
                 iterator,
+                parallelLimit(2),
                 counterStorage,
                 AsyncTask<expected_str<void>>(onCopySetup, onCopyDone),
             },
         };
 
-        m_taskTree.start(group, {}, [this](DoneWith result) {
+        m_taskTree.start(recipe, {}, [this](DoneWith result) {
             ProcessResultData resultData;
             if (result != DoneWith::Success) {
                 resultData.m_exitCode = -1;

src/plugins/remotelinux/linuxdevicetester.cpp

@@ -278,15 +278,14 @@ GroupItem GenericLinuxDeviceTesterPrivate::commandTasks() const
         emit q->errorMessage(message);
     };
 
-    const Group root {
+    return For {
+        iterator,
         continueOnError,
         onGroupSetup([this] {
             emit q->progressMessage(Tr::tr("Checking if required commands are available..."));
         }),
-        iterator,
         ProcessTask(onSetup, onDone)
     };
-    return root;
 }
 
 } // namespace Internal

tests/auto/solutions/tasking/tst_tasking.cpp

@@ -2735,12 +2735,12 @@ void tst_Tasking::testTree_data()
     {
         const QList<GroupItem> successItems {
             storage,
-            LoopRepeat(2),
             createSuccessTask(1),
             createSuccessTask(2)
         };
 
-        const Group rootSequentialSuccess {
+        const For rootSequentialSuccess {
+            LoopRepeat(2),
             sequential,
             successItems
         };
@@ -2755,7 +2755,8 @@ void tst_Tasking::testTree_data()
             {2, Handler::Success}
         };
 
-        const Group rootParallelSuccess {
+        const For rootParallelSuccess {
+            LoopRepeat(2),
             parallel,
             successItems
         };
@@ -2770,7 +2771,8 @@ void tst_Tasking::testTree_data()
             {2, Handler::Success}
         };
 
-        const Group rootParallelLimitSuccess {
+        const For rootParallelLimitSuccess {
+            LoopRepeat(2),
             parallelLimit(2),
             successItems
         };
@@ -2787,12 +2789,12 @@ void tst_Tasking::testTree_data()
 
         const QList<GroupItem> errorItems {
             storage,
-            LoopRepeat(2),
             createSuccessTask(1),
             createFailingTask(2)
         };
 
-        const Group rootSequentialError {
+        const For rootSequentialError {
+            LoopRepeat(2),
             sequential,
             errorItems
         };
@@ -2803,7 +2805,8 @@ void tst_Tasking::testTree_data()
             {2, Handler::Error}
         };
 
-        const Group rootParallelError {
+        const For rootParallelError {
+            LoopRepeat(2),
             parallel,
             errorItems
         };
@@ -2818,7 +2821,8 @@ void tst_Tasking::testTree_data()
             {2, Handler::Canceled}
         };
 
-        const Group rootParallelLimitError {
+        const For rootParallelLimitError {
+            LoopRepeat(2),
             parallelLimit(2),
             errorItems
         };
@@ -2873,12 +2877,12 @@ void tst_Tasking::testTree_data()
 
         const QList<GroupItem> items {
             storage,
-            loop,
             TestTask(onSetupContinue(1), onDone(1)),
             TestTask(onSetupStop(2), onDone(2))
         };
 
-        const Group rootSequential {
+        const For rootSequential {
+            loop,
             sequential,
             items
         };
@@ -2896,7 +2900,8 @@ void tst_Tasking::testTree_data()
             {22, Handler::Setup}
         };
 
-        const Group rootParallel {
+        const For rootParallel {
+            loop,
             parallel,
             items
         };
@@ -2914,7 +2919,8 @@ void tst_Tasking::testTree_data()
             {21, Handler::Success}
         };
 
-        const Group rootParallelLimit {
+        const For rootParallelLimit {
+            loop,
             parallelLimit(2),
             items
         };
@@ -2942,9 +2948,9 @@ void tst_Tasking::testTree_data()
 
     {
         // Check if task tree finishes with the right progress value when LoopUntil(false).
-        const Group root {
+        const For root {
-            storage,
             LoopUntil([](int) { return false; }),
+            storage,
             createSuccessTask(1)
         };
         QTest::newRow("ProgressWithLoopUntilFalse")
@@ -2953,10 +2959,10 @@ void tst_Tasking::testTree_data()
 
     {
         // Check if task tree finishes with the right progress value when nested LoopUntil(false).
-        const Group root {
+        const For root {
-            storage,
             LoopUntil([](int index) { return index < 2; }),
-            Group {
+            storage,
+            For {
                 LoopUntil([](int) { return false; }),
                 createSuccessTask(1)
             }
@@ -2978,9 +2984,9 @@ void tst_Tasking::testTree_data()
 
     {
         // Check if task tree finishes with the right progress value when nested LoopUntil(false).
-        const Group root {
+        const For root {
-            storage,
             LoopUntil([](int index) { return index < 2; }),
+            storage,
             Group {
                 onGroupSetup([] { return SetupResult::StopWithSuccess; }),
                 createSuccessTask(1)
@@ -3157,10 +3163,10 @@ void tst_Tasking::testTree_data()
             return DoneResult::Error;
         };
 
-        const Group root {
+        const For root {
+            iterator,
             storage,
             parallel,
-            iterator,
             TestTask(onSetup, onDone)
         };
 

tests/manual/tasking/assetdownloader/assetdownloader.cpp

@@ -509,9 +509,9 @@ void AssetDownloader::start()
             onGroupSetup(onSkipIfAllAssetsPresent),
             NetworkQueryTask(onZipDownloadSetup, onZipDownloadDone),
             ConcurrentCallTask<void>(onUnzipSetup, onUnzipDone),
-            Group {
+            For {
-                parallelIdealThreadCountLimit,
                 downloadIterator,
+                parallelIdealThreadCountLimit,
                 onGroupSetup(onAssetsDownloadGroupSetup),
                 Group {
                     assetStorage,
@@ -519,9 +519,9 @@ void AssetDownloader::start()
                     ConcurrentCallTask<void>(onAssetWriteSetup, onAssetWriteDone)
                 }
             },
-            Group {
+            For {
-                parallelIdealThreadCountLimit,
                 copyIterator,
+                parallelIdealThreadCountLimit,
                 onGroupSetup(onAssetsCopyGroupSetup),
                 ConcurrentCallTask<void>(onAssetCopySetup, onAssetCopyDone)
             }

tests/manual/tasking/dataexchange/recipe.cpp

@@ -74,7 +74,7 @@ Group recipe(const Storage<ExternalData> &externalStorage)
         internalStorage,
         NetworkQueryTask(onDownloadSetup, onDownloadDone),
         ConcurrentCallTask<QImage>(onReadSetup, onReadDone),
-        Group {
+        For {
             repeater,
             parallelIdealThreadCountLimit,
             ConcurrentCallTask<QImage>(onScaleSetup, onScaleDone)

tests/manual/tasking/imagescaling/imagescaling.cpp

@@ -93,10 +93,10 @@ void Images::process()
             labels[it]->setText(tr("Image\nData\nError."));
     };
 
-    const QList<GroupItem> tasks {
+    const For recipe {
+        iterator,
         finishAllAndSuccess,
         parallel,
-        iterator,
         onGroupSetup(onRootSetup),
         Group {
             storage,
@@ -105,8 +105,7 @@ void Images::process()
         },
         onGroupDone(onRootDone, CallDoneIf::Success)
     };
-
+    taskTreeRunner.start(recipe);
-    taskTreeRunner.start(tasks);
 }
 
 void Images::initLayout(qsizetype count)