1 files changed, 70 insertions, 0 deletions
diff --git a/zen/async_task.h b/zen/async_task.h
new file mode 100644
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--- /dev/null
+++ b/zen/async_task.h
@@ -0,0 +1,70 @@
+// **************************************************************************
+// * This file is part of the FreeFileSync project. It is distributed under *
+// * GNU General Public License: http://www.gnu.org/licenses/gpl.html       *
+// * Copyright (C) Zenju (zenju AT gmx DOT de) - All Rights Reserved        *
+// **************************************************************************
+
+#ifndef ASYNC_JOB_839147839170432143214321
+#define ASYNC_JOB_839147839170432143214321
+
+#include <list>
+#include <functional>
+#include <zen/thread.h>
+#include <zen/scope_guard.h>
+
+namespace zen
+{
+//run a job in an async thread, but process result on GUI event loop
+class AsyncTasks
+{
+public:
+    AsyncTasks() : inRecursion(false) {}
+
+    template <class Fun, class Fun2>
+    void add(Fun doAsync, Fun2 evalOnGui)
+    //equivalent to "evalOnGui(doAsync())"
+    //	-> doAsync: the usual thread-safety requirements apply!
+    //	-> evalOnGui: no thread-safety concerns, but must only reference variables with greater-equal lifetime than the AsyncTask instance!
+    {
+        tasks.push_back(zen::async([=]() -> std::function<void()>
+        {
+            auto result = doAsync();
+            return [=]{ evalOnGui(result); };
+        }));
+    }
+
+    template <class Fun, class Fun2>
+    void add2(Fun doAsync, Fun2 evalOnGui) //for doAsync returning void
+    {
+        tasks.push_back(zen::async([=]() -> std::function<void()> { doAsync(); return [=]{ evalOnGui(); }; }));
+    }
+
+    void evalResults() //call from gui thread repreatedly
+    {
+        if (!inRecursion) //prevent implicit recursion, e.g. if we're called from an idle event and spawn another one via the callback below
+        {
+            inRecursion = true;
+            ZEN_ON_SCOPE_EXIT(inRecursion = false);
+
+            tasks.remove_if([](boost::unique_future<std::function<void()>>& ft) -> bool
+            {
+                if (ft.is_ready())
+                {
+                    (ft.get())();
+                    return true;
+                }
+                return false;
+            });
+        }
+    }
+
+    bool empty() const { return tasks.empty(); }
+
+private:
+    bool inRecursion;
+    std::list<boost::unique_future<std::function<void()>>> tasks;
+};
+
+}
+
+#endif //ASYNC_JOB_839147839170432143214321