TaskTree: Add task tree adapter for task tree

Now it's possible to nest TaskTrees. A nested TaskTree
is seen as one, singular task inside parent tree.

Change-Id: Iad95de39c7b79580e0b589c222594de91d5b51a1
Reviewed-by: hjk <hjk@qt.io>

src/libs/utils/tasktree.cpp

@@ -535,4 +535,15 @@ int TaskTree::progressValue() const
     return d->m_progressValue;
 }
 
+TaskTreeAdapter::TaskTreeAdapter()
+{
+    connect(task(), &TaskTree::done, this, [this] { emit done(true); });
+    connect(task(), &TaskTree::errorOccurred, this, [this] { emit done(false); });
+}
+
+void TaskTreeAdapter::start()
+{
+    task()->start();
+}
+
 } // namespace Utils

src/libs/utils/tasktree.h

@@ -255,6 +255,13 @@ private:
     TaskTreePrivate *d;
 };
 
+class QTCREATOR_UTILS_EXPORT TaskTreeAdapter : public Tasking::TaskAdapter<TaskTree>
+{
+public:
+    TaskTreeAdapter();
+    void start() final;
+};
+
 } // namespace Utils
 
 #define QTC_DECLARE_CUSTOM_TASK(CustomTaskName, TaskAdapterClass)\
@@ -266,3 +273,4 @@ template <typename ...Args>\
 using CustomTaskName = CustomTask<TaskAdapterClass<Args...>>;\
 } // namespace Utils::Tasking
 
+QTC_DECLARE_CUSTOM_TASK(Tree, Utils::TaskTreeAdapter);

tests/auto/utils/tasktree/tst_tasktree.cpp

@@ -246,6 +246,20 @@ void tst_TaskTree::processTree_data()
         },
         OnGroupDone(rootDone)
     };
+    auto setupSubTree = [=](TaskTree &taskTree) {
+        const Group nestedRoot {
+            Process(std::bind(setupProcess, _1, 2), readResult),
+            Process(std::bind(setupProcess, _1, 3), readResult),
+            Process(std::bind(setupProcess, _1, 4), readResult),
+        };
+        taskTree.setupRoot(nestedRoot);
+    };
+    const Group sequentialSubTreeRoot {
+        Process(std::bind(setupProcess, _1, 1), readResult),
+        Tree(setupSubTree),
+        Process(std::bind(setupProcess, _1, 5), readResult),
+        OnGroupDone(rootDone)
+    };
     const Log sequentialLog{{1, Handler::Setup},
                             {1, Handler::Done},
                             {2, Handler::Setup},
@@ -260,6 +274,8 @@ void tst_TaskTree::processTree_data()
     QTest::newRow("Sequential") << sequentialRoot << sequentialLog << true << true << 5;
     QTest::newRow("SequentialEncapsulated") << sequentialEncapsulatedRoot << sequentialLog
                                             << true << true << 5;
+    QTest::newRow("SequentialSubTree") << sequentialSubTreeRoot << sequentialLog
+                                       << true << true << 3; // We don't inspect subtrees
 
     const Group sequentialNestedRoot {
         Group {
@@ -439,6 +455,7 @@ void tst_TaskTree::processTree_data()
                                  {-1, Handler::GroupDone}};
     QTest::newRow("DynamicSetupSelected") << dynamicSetupSelRoot << dynamicSetupSelLog
                                           << true << true << 4;
+
 }
 
 void tst_TaskTree::processTree()