TaskTree: Introduce withCancel() helper

The withCancel() method takes a function returning the sender
and its signal pair. When the signal is emitted, the queued
call to the running task tree is scheduled, and when dispatched
the *this group is canceled and the returned item finishes with an
error.

Change-Id: I898a7221d91a78225c73abc6885a18a2e7c2ae45
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

2 files changed, 34 insertions, 0 deletions

diff --git a/src/libs/solutions/tasking/tasktree.cpp b/src/libs/solutions/tasking/tasktree.cpp
index 8b8d1176c0..107559d6a5 100644
--- a/src/libs/solutions/tasking/tasktree.cpp
+++ b/src/libs/solutions/tasking/tasktree.cpp
@@ -3,6 +3,8 @@
 
 #include "tasktree.h"
 
+#include "barrier.h"
+
 #include <QDebug>
 #include <QEventLoop>
 #include <QFutureWatcher>
@@ -1488,6 +1490,23 @@ ExecutableItem ExecutableItem::withLog(const QString &logName) const
     };
 }
 
+ExecutableItem ExecutableItem::withCancelImpl(
+    const std::function<void(QObject *, const std::function<void()> &)> &connectWrapper) const
+{
+    const auto onSetup = [connectWrapper](Barrier &barrier) {
+        connectWrapper(&barrier, [barrierPtr = &barrier] { barrierPtr->advance(); });
+    };
+    return Group {
+        parallel,
+        stopOnSuccessOrError,
+        Group {
+            finishAllAndError,
+            BarrierTask(onSetup)
+        },
+        *this
+    };
+}
+
 class TaskTreePrivate;
 class TaskNode;
 class RuntimeContainer;
diff --git a/src/libs/solutions/tasking/tasktree.h b/src/libs/solutions/tasking/tasktree.h
index 29ec554815..9b1e4b9eaf 100644
--- a/src/libs/solutions/tasking/tasktree.h
+++ b/src/libs/solutions/tasking/tasktree.h
@@ -290,10 +290,25 @@ public:
     ExecutableItem withTimeout(std::chrono::milliseconds timeout,
                                const std::function<void()> &handler = {}) const;
     ExecutableItem withLog(const QString &logName) const;
+    template <typename SenderSignalPairGetter>
+    ExecutableItem withCancel(SenderSignalPairGetter &&getter) const
+    {
+        const auto connectWrapper = [getter](QObject *guard, const std::function<void()> &trigger) {
+            const auto senderSignalPair = getter();
+            QObject::connect(senderSignalPair.first, senderSignalPair.second, guard, [trigger] {
+                trigger();
+            }, static_cast<Qt::ConnectionType>(Qt::QueuedConnection | Qt::SingleShotConnection));
+        };
+        return withCancelImpl(connectWrapper);
+    }
 
 protected:
     ExecutableItem() = default;
     ExecutableItem(const TaskHandler &handler) : GroupItem(handler) {}
+
+private:
+    ExecutableItem withCancelImpl(
+        const std::function<void(QObject *, const std::function<void()> &)> &connectWrapper) const;
 };
 
 class TASKING_EXPORT Group : public ExecutableItem