TaskTree: Add Task c'tor taking one handler for done and error

The overloaded c'tor takes one done handler with an additional
"bool success" argument.

Task-number: QTCREATORBUG-29834
Change-Id: Id579d055721a2a07a5a9f0900aa4a73655f21610
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>

src/libs/solutions/tasking/tasktree.h

@@ -324,6 +324,7 @@ public:
     static_assert(std::is_base_of_v<TaskAdapter<Task, Deleter>, Adapter>,
                   "The Adapter type for the CustomTask<Adapter> needs to be derived from "
                   "TaskAdapter<Task>.");
+    using DoneHandler = std::function<void(const Task &, bool)>;
     using EndHandler = std::function<void(const Task &)>;
     static Adapter *createAdapter() { return new Adapter; }
     CustomTask() : GroupItem({&createAdapter}) {}
@@ -332,6 +333,11 @@ public:
         : GroupItem({&createAdapter, wrapSetup(std::forward<SetupHandler>(setup)),
                      wrapEnds(done, error)}) {}
 
+    template <typename SetupHandler>
+    CustomTask(SetupHandler &&setup, const DoneHandler &done)
+        : GroupItem({&createAdapter, wrapSetup(std::forward<SetupHandler>(setup)), wrapDone(done)})
+    {}
+
     GroupItem withTimeout(std::chrono::milliseconds timeout,
                           const GroupEndHandler &handler = {}) const {
         return GroupItem::withTimeout(*this, timeout, handler);
@@ -366,6 +372,15 @@ private:
                 handler(*adapter.task());
         };
     };
+
+    static TaskDoneHandler wrapDone(const DoneHandler &handler) {
+        if (!handler)
+            return {};
+        return [handler](const TaskInterface &taskInterface, bool success) {
+            const Adapter &adapter = static_cast<const Adapter &>(taskInterface);
+            handler(*adapter.task(), success);
+        };
+    };
 };
 
 class TaskTreePrivate;