debuged some horrible race conditions & deadlocks

src/gfx/resample_image.cpp

@@ -144,6 +144,8 @@ void resample_and_clip(const Image& img_in, Image& img_out, wxRect rect) {
 // fill an image with 100% transparent, except for the given rectangle
 void fill_transparent(Image& img, int dx, int dy, int w, int h) {
 	if (!img.HasAlpha()) img.InitAlpha();
+	memset(img.GetAlpha(), 0, img.GetWidth() * img.GetHeight());
+	/*/?
 	int iw = img.GetWidth(), ih = img.GetHeight();
 	Byte* data = img.GetAlpha();
 	// fill
@@ -160,6 +162,7 @@ void fill_transparent(Image& img, int dx, int dy, int w, int h) {
 	for (; y < ih ; ++y) {
 		for (int x = 0 ; x < iw ; ++x) *data++ = 0;
 	}
+	*/
 }
 
 void resample_preserve_aspect(const Image& img_in, Image& img_out) {

src/gui/drop_down_list.cpp

@@ -37,8 +37,10 @@ class DropDownHider : public wxEvtHandler {
 			// don't just use ev.Skip(), because this event handler will be removed by hiding,
 			// so there will be no next handler to skip to
 			wxEvtHandler* nh = GetNextHandler();
+			wxLogDebug(L"close to %p", nh);
 			list.hide(false);
 			if (nh) nh->ProcessEvent(ev);
+			wxLogDebug(L"/close to %p", nh);
 			return false;
 		} else {
 //			if (t !=10093 && t !=10098 && t !=10097 && t !=10099 && t !=10004 && t !=10062

src/gui/thumbnail_thread.cpp

@@ -58,7 +58,6 @@ wxThread::ExitCode ThumbnailThreadWorker::Entry() {
 	while (true) {
 		do {
 			Sleep(1);
-			if (TestDestroy()) return 0;
 		} while (stop);
 		// get a request
 		{
@@ -71,9 +70,7 @@ wxThread::ExitCode ThumbnailThreadWorker::Entry() {
 			parent->open_requests.pop_front();
 		}
 		// perform request
-		if (TestDestroy()) return 0;
 		Image img = current->generate();
-		if (TestDestroy()) return 0;
 		// store in cache
 		if (img.Ok()) {
 			String filename = image_cache_dir() + safe_filename(current->cache_name) + _(".png");
@@ -107,10 +104,6 @@ ThumbnailThread::ThumbnailThread()
 	, worker(nullptr)
 {}
 
-ThumbnailThread::~ThumbnailThread() {
-	abortAll();
-}
-
 void ThumbnailThread::request(const ThumbnailRequestP& request) {
 	assert(wxThread::IsMain());
 	// Is the request in progress?
@@ -172,7 +165,7 @@ bool ThumbnailThread::done(void* owner) {
 void ThumbnailThread::abort(void* owner) {
 	assert(wxThread::IsMain());
 	mutex.Lock();
-	if (worker && worker->current->owner == owner) {
+	if (worker && worker->current && worker->current->owner == owner) {
 		// a request for this owner is in progress, wait until it is done
 		worker->stop = true;
 		completed.Wait();
@@ -183,8 +176,8 @@ void ThumbnailThread::abort(void* owner) {
 	for (size_t i = 0 ; i < open_requests.size() ; ) {
 		if (open_requests[i]->owner == owner) {
 			// remove
-			open_requests.erase(open_requests.begin() + i, open_requests.begin() + i + 1);
 			request_names.erase(open_requests[i]);
+			open_requests.erase(open_requests.begin() + i, open_requests.begin() + i + 1);
 		} else {
 			++i;
 		}
@@ -193,8 +186,8 @@ void ThumbnailThread::abort(void* owner) {
 	for (size_t i = 0 ; i < closed_requests.size() ; ) {
 		if (closed_requests[i].first->owner == owner) {
 			// remove
-			closed_requests.erase(closed_requests.begin() + i, closed_requests.begin() + i + 1);
 			request_names.erase(closed_requests[i].first);
+			closed_requests.erase(closed_requests.begin() + i, closed_requests.begin() + i + 1);
 		} else {
 			++i;
 		}
@@ -208,10 +201,14 @@ void ThumbnailThread::abortAll() {
 	open_requests.clear();
 	closed_requests.clear();
 	request_names.clear();
-	if (worker) {
-		// a request is in progress, wait until it is done, killing the worker
+	// end worker
+	if (worker && worker->current) {
 		completed.Wait();
 	} else {
 		mutex.Unlock();
 	}
+	// There may still be a worker, but if there is, it has no current object, so it is
+	// in, before or after the stop loop. It can do nothing but end.
+	// An unfortunate side effect is that we might leak some memory (of the worker object),
+	// when the thread gets Kill()ed by wx.
 }

src/gui/thumbnail_thread.hpp

@@ -48,7 +48,6 @@ class ThumbnailRequest {
 class ThumbnailThread {
   public:
 	ThumbnailThread();
-	~ThumbnailThread();
 	
 	/// Request a thumbnail, it may be store()d immediatly if the thumbnail is cached
 	void request(const ThumbnailRequestP& request);
@@ -58,6 +57,7 @@ class ThumbnailThread {
 	/// Abort all thumbnail requests for the given owner
 	void abort(void* owner);
 	/// Abort all computations
+	/** *must* be called at application exit */
 	void abortAll();
 	
   private:

src/gui/value/choice.cpp

@@ -66,7 +66,9 @@ DropDownChoiceList::DropDownChoiceList(Window* parent, bool is_submenu, ChoiceVa
 	, group(group)
 	, cve(cve)
 {
-	icon_size.width = 16;
+	icon_size.width  = 16;
+	icon_size.height = 16;
+	item_size.height = max(16., item_size.height);
 }
 
 size_t DropDownChoiceList::itemCount() const {
@@ -183,7 +185,9 @@ void DropDownChoiceList::generateThumbnailImages() {
 
 void DropDownChoiceList::onIdle(wxIdleEvent& ev) {
 	if (!isRoot()) return;
-	thumbnail_thread.done(&cve);
+	if (thumbnail_thread.done(&cve)) {
+		Refresh(false);
+	}
 }
 
 BEGIN_EVENT_TABLE(DropDownChoiceList, DropDownList)
@@ -201,6 +205,8 @@ ChoiceValueEditor::~ChoiceValueEditor() {
 }
 
 void ChoiceValueEditor::onLeftDown(const RealPoint& pos, wxMouseEvent& ev) {
+	//HACK TODO REMOVEME
+	thumbnail_thread.abortAll();
 	drop_down->onMouseInParent(ev, style().popup_style == POPUP_DROPDOWN_IN_PLACE && !nativeLook());
 }
 void ChoiceValueEditor::onChar(wxKeyEvent& ev) {

src/main.cpp

@@ -17,6 +17,7 @@
 #include <gui/update_checker.hpp>
 #include <gui/set/window.hpp>
 #include <gui/symbol/window.hpp>
+#include <gui/thumbnail_thread.hpp>
 #include <wx/fs_inet.h>
 
 // ----------------------------------------------------------------------------- : Main function/class
@@ -73,6 +74,7 @@ bool MSE::OnInit() {
 // ----------------------------------------------------------------------------- : Exit
 
 int MSE::OnExit() {
+	thumbnail_thread.abortAll();
 	settings.write();
 	packages.destroy();
 	return 0;