Fix deadlock when canceling the slicing while creating thumbnails

src/libslic3r/Config.hpp

@@ -169,7 +169,7 @@ enum PrinterTechnology : uint8_t
     // Laser engraving
     ptLaser = 1 << 4,
     // Any technology, useful for parameters compatible with both ptFFF and ptSLA
-    ptAny = 1+2+4,
+    ptAny = ptFFF | ptSLA | ptSLS | ptMill | ptLaser,
     // Unknown, useful for command line processing
     ptUnknown = 1 << 7
 };

src/libslic3r/GCode.cpp

@@ -849,10 +849,16 @@ namespace DoExport {
             for (const Vec2d &size : sizes)
                 if (size.x() > 0 && size.y() > 0)
                     good_sizes.push_back(size);
+            if (good_sizes.empty()) return;
 
+            //Create the thumbnails
 	        const size_t max_row_length = 78;
 	        ThumbnailsList thumbnails;
-	        thumbnail_cb(thumbnails, good_sizes, true, true, thumbnails_with_bed, true);
+            // note that it needs the gui thread, so can create deadlock if  job is canceled.
+	        bool can_create_thumbnail = thumbnail_cb(thumbnails, good_sizes, true, true, thumbnails_with_bed, true);
+            throw_if_canceled();
+            if (!can_create_thumbnail) return;
+
 	        for (const ThumbnailData& data : thumbnails)
 	        {
 	            if (data.is_valid())

src/libslic3r/GCode/ThumbnailData.hpp

@@ -20,7 +20,7 @@ struct ThumbnailData
 };
 
 typedef std::vector<ThumbnailData> ThumbnailsList;
-typedef std::function<void(ThumbnailsList & thumbnails, const Vec2ds & sizes, bool printable_only, bool parts_only, bool show_bed, bool transparent_background)> ThumbnailsGeneratorCallback;
+typedef std::function<bool(ThumbnailsList & thumbnails, const Vec2ds & sizes, bool printable_only, bool parts_only, bool show_bed, bool transparent_background)> ThumbnailsGeneratorCallback;
 
 } // namespace Slic3r
 

src/slic3r/GUI/GLCanvas3D.cpp

@@ -1206,7 +1206,7 @@ GLCanvas3D::GLCanvas3D(wxGLCanvas* canvas)
 
 GLCanvas3D::~GLCanvas3D()
 {
-    reset_volumes();
+    reset_volumes(true);
 }
 
 void GLCanvas3D::post_event(wxEvent &&event)
@@ -1303,7 +1303,7 @@ unsigned int GLCanvas3D::get_volumes_count() const
     return (unsigned int)m_volumes.volumes.size();
 }
 
-void GLCanvas3D::reset_volumes()
+void GLCanvas3D::reset_volumes(bool is_destroying)
 {
     if (!m_initialized)
         return;
@@ -1313,11 +1313,12 @@ void GLCanvas3D::reset_volumes()
 
     _set_current();
 
-        m_selection.clear();
+        m_selection.clear(is_destroying);
         m_volumes.clear();
         m_dirty = true;
 
-    _set_warning_texture(WarningTexture::ObjectOutside, false);
+    if(!is_destroying)
+        _set_warning_texture(WarningTexture::ObjectOutside, false);
 }
 
 int GLCanvas3D::check_volumes_outside_state() const

src/slic3r/GUI/GLCanvas3D.hpp

@@ -558,7 +558,7 @@ public:
 
     unsigned int get_volumes_count() const;
     const GLVolumeCollection& get_volumes() const { return m_volumes; }
-    void reset_volumes();
+    void reset_volumes(bool is_destroying = false);
     int check_volumes_outside_state() const;
 
     void reset_gcode_toolpaths() { m_gcode_viewer.reset(); }

src/slic3r/GUI/Plater.cpp

@@ -2001,14 +2001,43 @@ Plater::priv::priv(Plater *q, MainFrame *main_frame)
     background_process.set_fff_print(&fff_print);
     background_process.set_sla_print(&sla_print);
     background_process.set_gcode_result(&gcode_result);
-    background_process.set_thumbnail_cb([this](ThumbnailsList& thumbnails, const Vec2ds& sizes, bool printable_only, bool parts_only, bool show_bed, bool transparent_background)
+    background_process.set_thumbnail_cb([this](ThumbnailsList& thumbnails, const Vec2ds& sizes, bool printable_only, bool parts_only, bool show_bed, bool transparent_background)->bool
         {
-            std::packaged_task<void(ThumbnailsList&, const Vec2ds&, bool, bool, bool, bool)> task([this](ThumbnailsList& thumbnails, const Vec2ds& sizes, bool printable_only, bool parts_only, bool show_bed, bool transparent_background) {
+            auto task = std::make_shared<std::packaged_task<void(ThumbnailsList&, const Vec2ds&, bool, bool, bool, bool)>>([this](ThumbnailsList& thumbnails, const Vec2ds& sizes, bool printable_only, bool parts_only, bool show_bed, bool transparent_background) {
                 generate_thumbnails(thumbnails, sizes, printable_only, parts_only, show_bed, transparent_background);
                 });
-            std::future<void> result = task.get_future();
-            wxTheApp->CallAfter([&]() { task(thumbnails, sizes, printable_only, parts_only, show_bed, transparent_background); });
-            result.wait();
+
+            std::future<void> future_result = task->get_future();
+            std::shared_ptr<std::mutex> protect_bool = std::make_shared<std::mutex>();
+            std::shared_ptr<bool> is_started = std::make_shared<bool>(false);
+            std::shared_ptr<bool> cancel = std::make_shared<bool>(false);
+            wxTheApp->CallAfter([task, protect_bool, is_started, cancel, &thumbnails, &sizes, &printable_only, &parts_only, &show_bed, &transparent_background]()
+            { 
+                {
+                    std::lock_guard<std::mutex> lock(*protect_bool);
+                    if (*cancel)
+                        return;
+                    *is_started = true;
+                }
+                (*task)(thumbnails, sizes, printable_only, parts_only, show_bed, transparent_background); 
+            });
+            // can deadlock if background processing is cancelled / locked
+            // have to cancel the process if we're exiting here as the parameters will be deleted.
+            // if the process is already started, then we have to wait its end. and there is no deadlock with generate_thumbnails
+            // 2 seconds is plenty to 
+            std::future_status result = future_result.wait_for(std::chrono::seconds(2));
+            if (result == std::future_status::ready)
+                return true;
+            {
+                std::lock_guard<std::mutex> lock(*protect_bool);
+                if (*is_started) {
+                    future_result.wait();
+                    result = std::future_status::ready;
+                } else {
+                    *cancel = true;
+                }
+            }
+            return result == std::future_status::ready;
         });
     background_process.set_slicing_completed_event(EVT_SLICING_COMPLETED);
     background_process.set_finished_event(EVT_PROCESS_COMPLETED);

src/slic3r/GUI/Selection.cpp

@@ -447,7 +447,7 @@ void Selection::set_deserialized(EMode mode, const std::vector<std::pair<size_t,
     this->set_bounding_boxes_dirty();
 }
 
-void Selection::clear()
+void Selection::clear(bool is_destroying)
 {
     if (!m_valid)
         return;
@@ -466,7 +466,7 @@ void Selection::clear()
     this->set_bounding_boxes_dirty();
 
     // this happens while the application is closing
-    if (wxGetApp().obj_manipul() == nullptr)
+    if (is_destroying || wxGetApp().obj_manipul() == nullptr)
         return;
 
     // resets the cache in the sidebar

src/slic3r/GUI/Selection.hpp

@@ -268,7 +268,7 @@ public:
     // Update the selection based on the map from old indices to new indices after m_volumes changed.
     // If the current selection is by instance, this call may select newly added volumes, if they belong to already selected instances.
     void volumes_changed(const std::vector<size_t> &map_volume_old_to_new);
-    void clear();
+    void clear(bool is_destroying = false);
 
     bool is_empty() const { return m_type == Empty; }
     bool is_wipe_tower() const { return m_type == WipeTower; }