TaskTree: Introduce ParallelLimit

The parallel limit constrains the number of parallel tasks
run in the same time. So, if e.g. a group contains 10 children
and the parallel limit is 6, only first 6 tasks are being started
on the beginning and the rest 4 are being postponed until some
running tasks are finished. So, when the one of 6 running tasks
finishes the group starts the 7th task and so on.

Setting parallel limit to 1 means sequential invocation in fact.

The value of 0 means there is no limit and all tasks are run at once.

Remove the ExecuteMode enum, as this is modelled now by the
parallelLimit.

Change-Id: Ice59318be0915401f05bb5a5804078bdc591d09f
Reviewed-by: hjk <hjk@qt.io>

3 files changed, 19 insertions, 14 deletions

diff --git a/tests/manual/tasktree/main.cpp b/tests/manual/tasktree/main.cpp
index e0a0048374..b57481bfc4 100644
--- a/tests/manual/tasktree/main.cpp
+++ b/tests/manual/tasktree/main.cpp
@@ -102,7 +102,7 @@ int main(int argc, char *argv[])
 
     groupTask_1->setWorkflowPolicy(Tasking::WorkflowPolicy::ContinueOnDone);
     groupTask_4->setWorkflowPolicy(Tasking::WorkflowPolicy::Optional);
-    groupTask_4_3->setExecuteMode(Tasking::ExecuteMode::Parallel);
+    groupTask_4_3->setExecuteMode(ExecuteMode::Parallel);
     groupTask_4_3->setWorkflowPolicy(Tasking::WorkflowPolicy::StopOnError);
 
     // Task layout
@@ -170,14 +170,14 @@ int main(int argc, char *argv[])
         };
 
         const Group root {
-            Execute(rootGroup->executeMode()),
+            rootGroup->executeMode(),
             Workflow(rootGroup->workflowPolicy()),
             OnGroupSetup([rootGroup] { rootGroup->setState(State::Running); }),
             OnGroupDone([rootGroup] { rootGroup->setState(State::Done); }),
             OnGroupError([rootGroup] { rootGroup->setState(State::Error); }),
 
             Group {
-                Execute(groupTask_1->executeMode()),
+                groupTask_1->executeMode(),
                 Workflow(groupTask_1->workflowPolicy()),
                 OnGroupSetup([groupTask_1] { groupTask_1->setState(State::Running); }),
                 OnGroupDone([groupTask_1] { groupTask_1->setState(State::Done); }),
@@ -190,7 +190,7 @@ int main(int argc, char *argv[])
             taskItem(task_2),
             taskItem(task_3),
             Group {
-                Execute(groupTask_4->executeMode()),
+                groupTask_4->executeMode(),
                 Workflow(groupTask_4->workflowPolicy()),
                 OnGroupSetup([groupTask_4] { groupTask_4->setState(State::Running); }),
                 OnGroupDone([groupTask_4] { groupTask_4->setState(State::Done); }),
@@ -199,7 +199,7 @@ int main(int argc, char *argv[])
                 taskItem(task_4_1),
                 taskItem(task_4_2),
                 Group {
-                    Execute(groupTask_4_3->executeMode()),
+                    groupTask_4_3->executeMode(),
                     Workflow(groupTask_4_3->workflowPolicy()),
                     OnGroupSetup([groupTask_4_3] { groupTask_4_3->setState(State::Running); }),
                     OnGroupDone([groupTask_4_3] { groupTask_4_3->setState(State::Done); }),
diff --git a/tests/manual/tasktree/taskwidget.cpp b/tests/manual/tasktree/taskwidget.cpp
index a6901f8d13..d4ddc0194a 100644
--- a/tests/manual/tasktree/taskwidget.cpp
+++ b/tests/manual/tasktree/taskwidget.cpp
@@ -121,11 +121,11 @@ GroupWidget::GroupWidget()
 {
     m_stateIndicator->setFixedWidth(30);
 
-    m_executeCombo->addItem("Sequential", (int)Tasking::ExecuteMode::Sequential);
-    m_executeCombo->addItem("Parallel", (int)Tasking::ExecuteMode::Parallel);
+    m_executeCombo->addItem("Sequential", (int)ExecuteMode::Sequential);
+    m_executeCombo->addItem("Parallel", (int)ExecuteMode::Parallel);
     updateExecuteMode();
     connect(m_executeCombo, &QComboBox::currentIndexChanged, this, [this](int index) {
-        m_executeMode = (Tasking::ExecuteMode)m_executeCombo->itemData(index).toInt();
+        m_executeMode = (ExecuteMode)m_executeCombo->itemData(index).toInt();
     });
 
     m_workflowCombo->addItem("Stop On Error", (int)Tasking::WorkflowPolicy::StopOnError);
@@ -152,7 +152,7 @@ GroupWidget::GroupWidget()
     setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Preferred);
 }
 
-void GroupWidget::setExecuteMode(Tasking::ExecuteMode mode)
+void GroupWidget::setExecuteMode(ExecuteMode mode)
 {
     m_executeMode = mode;
     updateExecuteMode();
@@ -163,9 +163,9 @@ void GroupWidget::updateExecuteMode()
     m_executeCombo->setCurrentIndex(m_executeCombo->findData((int)m_executeMode));
 }
 
-Tasking::ExecuteMode GroupWidget::executeMode() const
+Tasking::ParallelLimit GroupWidget::executeMode() const
 {
-    return m_executeMode;
+    return m_executeMode == ExecuteMode::Sequential ? Tasking::sequential : Tasking::parallel;
 }
 
 void GroupWidget::setWorkflowPolicy(Tasking::WorkflowPolicy policy)
diff --git a/tests/manual/tasktree/taskwidget.h b/tests/manual/tasktree/taskwidget.h
index be21ae02e9..7421ca5a30 100644
--- a/tests/manual/tasktree/taskwidget.h
+++ b/tests/manual/tasktree/taskwidget.h
@@ -22,6 +22,11 @@ enum class State {
     Error
 };
 
+enum class ExecuteMode {
+    Sequential, // default
+    Parallel
+};
+
 class StateWidget : public QWidget
 {
 public:
@@ -54,8 +59,8 @@ class GroupWidget : public StateWidget
 public:
     GroupWidget();
 
-    void setExecuteMode(Utils::Tasking::ExecuteMode mode);
-    Utils::Tasking::ExecuteMode executeMode() const;
+    void setExecuteMode(ExecuteMode mode);
+    Utils::Tasking::ParallelLimit executeMode() const;
 
     void setWorkflowPolicy(Utils::Tasking::WorkflowPolicy policy);
     Utils::Tasking::WorkflowPolicy workflowPolicy() const;
@@ -67,7 +72,7 @@ private:
     QComboBox *m_executeCombo = nullptr;
     QComboBox *m_workflowCombo = nullptr;
 
-    Utils::Tasking::ExecuteMode m_executeMode = Utils::Tasking::ExecuteMode::Sequential;
+    ExecuteMode m_executeMode = ExecuteMode::Sequential;
     Utils::Tasking::WorkflowPolicy m_workflowPolicy = Utils::Tasking::WorkflowPolicy::StopOnError;
 };