Add CancellableJob for cancelling only a specific job instance

src/slic3r/CMakeLists.txt

@@ -192,6 +192,7 @@ set(SLIC3R_GUI_SOURCES
     GUI/Jobs/BoostThreadWorker.cpp
     GUI/Jobs/UIThreadWorker.hpp
     GUI/Jobs/BusyCursorJob.hpp
+    GUI/Jobs/CancellableJob.hpp
     GUI/Jobs/PlaterWorker.hpp
     GUI/Jobs/ArrangeJob.hpp
     GUI/Jobs/ArrangeJob.cpp

src/slic3r/GUI/Jobs/CancellableJob.hpp

@@ -0,0 +1,60 @@
+#ifndef CANCELLABLEJOB_HPP
+#define CANCELLABLEJOB_HPP
+
+#include <atomic>
+
+#include "Job.hpp"
+
+namespace Slic3r { namespace GUI {
+
+template<class JobSubclass>
+class CancellableJob: public Job {
+    JobSubclass m_job;
+    std::atomic_bool &m_flag;
+
+public:
+    template<class... Args>
+    CancellableJob(std::atomic_bool &flag, Args &&...args)
+        : m_job{std::forward<Args>(args)...}, m_flag{flag}
+    {}
+
+    void process(Ctl &ctl) override
+    {
+        m_flag.store(false);
+
+        struct CancelCtl : public Ctl
+        {
+            Ctl              &basectl;
+            std::atomic_bool &cflag;
+
+            CancelCtl (Ctl &c, std::atomic_bool &f): basectl{c}, cflag{f} {}
+
+            void update_status(int st, const std::string &msg = "") override
+            {
+                basectl.update_status(st, msg);
+            }
+
+            bool was_canceled() const override
+            {
+                return cflag.load() || basectl.was_canceled();
+            }
+
+            std::future<void> call_on_main_thread(
+                std::function<void()> fn) override
+            {
+                return basectl.call_on_main_thread(fn);
+            }
+        } cctl(ctl, m_flag);
+
+        m_job.process(cctl);
+    }
+
+    void finalize(bool canceled, std::exception_ptr &eptr) override
+    {
+        m_job.finalize(m_flag.load() || canceled, eptr);
+    }
+};
+
+}} // namespace Slic3r::GUI
+
+#endif // CANCELLABLEJOB_HPP