Utils: Introduce AsyncTask

AsyncTask encapsulates a function and arguments list
for further asynchronous invocation (using Utils::runAsync).
This is going to be a part of TaskTree hierarchy.
It will enable keeping asynchronous tasks inside the tree.

This means we will be able to construct a task tree
consisting of a mixture of processes and asynchronous tasks.

Implementation-wise this is a simple templated subclass of QObject,
where template parameter is of asynchronous result's type.
It holds QFutureWatcher object internally in order to
track task's running state.

Change-Id: I96f307cdf663cadc840465debb353ab55a2c3550
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

4 files changed, 91 insertions, 0 deletions

diff --git a/src/libs/utils/CMakeLists.txt b/src/libs/utils/CMakeLists.txt
index 362a0b0eeb..3e0a7a836d 100644
--- a/src/libs/utils/CMakeLists.txt
+++ b/src/libs/utils/CMakeLists.txt
@@ -11,6 +11,7 @@ add_qtc_library(Utils
     appmainwindow.cpp appmainwindow.h
     archive.cpp archive.h
     aspects.cpp aspects.h
+    asynctask.cpp asynctask.h
     basetreeview.cpp basetreeview.h
     benchmarker.cpp benchmarker.h
     buildablehelperlibrary.cpp buildablehelperlibrary.h
diff --git a/src/libs/utils/asynctask.cpp b/src/libs/utils/asynctask.cpp
new file mode 100644
index 0000000000..ff79035472
--- /dev/null
+++ b/src/libs/utils/asynctask.cpp
@@ -0,0 +1,8 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
+
+#include "asynctask.h"
+
+namespace Utils {
+
+} // namespace Utils
diff --git a/src/libs/utils/asynctask.h b/src/libs/utils/asynctask.h
new file mode 100644
index 0000000000..3b46b5aa8b
--- /dev/null
+++ b/src/libs/utils/asynctask.h
@@ -0,0 +1,80 @@
+// Copyright (C) 2022 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
+
+#pragma once
+
+#include "utils_global.h"
+
+#include "futuresynchronizer.h"
+#include "qtcassert.h"
+#include "runextensions.h"
+
+#include <QFutureWatcher>
+
+namespace Utils {
+
+class QTCREATOR_UTILS_EXPORT AsyncTaskBase : public QObject
+{
+    Q_OBJECT
+
+signals:
+    void started();
+    void done();
+};
+
+template <typename ResultType>
+class AsyncTask : public AsyncTaskBase
+{
+public:
+    AsyncTask() { connect(&m_watcher, &QFutureWatcherBase::finished, this, &AsyncTaskBase::done); }
+    ~AsyncTask()
+    {
+        if (isDone())
+            return;
+
+        m_watcher.cancel();
+        if (!m_synchronizer)
+            m_watcher.waitForFinished();
+    }
+
+    using StartHandler = std::function<QFuture<ResultType>()>;
+
+    template <typename Function, typename ...Args>
+    void setAsyncCallData(const Function &function, const Args &...args)
+    {
+        m_startHandler = [=] {
+            return Internal::runAsync_internal(m_threadPool, m_stackSize, m_priority,
+                                               function, args...);
+        };
+    }
+    void setFutureSynchronizer(FutureSynchronizer *synchorizer) { m_synchronizer = synchorizer; }
+    void setThreadPool(QThreadPool *pool) { m_threadPool = pool; }
+    void setStackSizeInBytes(const StackSizeInBytes &size) { m_stackSize = size; }
+    void setPriority(QThread::Priority priority) { m_priority = priority; }
+
+    void start()
+    {
+        QTC_ASSERT(m_startHandler, qWarning("No start handler specified."); return);
+        m_watcher.setFuture(m_startHandler());
+        emit started();
+        if (m_synchronizer)
+            m_synchronizer->addFuture(m_watcher.future());
+    }
+
+    bool isDone() const { return m_watcher.isFinished(); }
+    bool isCanceled() const { return m_watcher.isCanceled(); }
+
+    QFuture<ResultType> future() const { return m_watcher.future(); }
+    ResultType result() const { return m_watcher.result(); } // TODO: warn when isRunning?
+    QList<ResultType> results() const { return m_watcher.future().results(); }
+
+private:
+    StartHandler m_startHandler;
+    FutureSynchronizer *m_synchronizer = nullptr;
+    QThreadPool *m_threadPool = nullptr;
+    QThread::Priority m_priority = QThread::InheritPriority;
+    StackSizeInBytes m_stackSize = {};
+    QFutureWatcher<ResultType> m_watcher;
+};
+
+} // namespace Utils
diff --git a/src/libs/utils/utils.qbs b/src/libs/utils/utils.qbs
index 79d9561727..6415aaca9f 100644
--- a/src/libs/utils/utils.qbs
+++ b/src/libs/utils/utils.qbs
@@ -50,6 +50,8 @@ Project {
             "archive.h",
             "aspects.cpp",
             "aspects.h",
+            "asynctask.cpp",
+            "asynctask.h",
             "basetreeview.cpp",
             "basetreeview.h",
             "benchmarker.cpp",