TH_CLEAN_3: Use of non-blocking try_pop() when possible,

AudioThread concurrent access hardening and simplified,
and misc.

src/visual/ScopeCanvas.cpp

@@ -97,11 +97,10 @@ bool ScopeCanvas::getShowDb() {
 void ScopeCanvas::OnPaint(wxPaintEvent& WXUNUSED(event)) {
     wxPaintDC dc(this);
     const wxSize ClientSize = GetClientSize();
-
-    while (!inputData.empty()) {
-        ScopeRenderData *avData;
-        inputData.pop(avData);
-
+    
+    ScopeRenderData *avData;
+    while (inputData.try_pop(avData)) {
+       
         
         if (!avData->spectrum) {
             scopePanel.setMode(avData->mode);

src/visual/SpectrumCanvas.cpp

@@ -51,11 +51,9 @@ void SpectrumCanvas::OnPaint(wxPaintEvent& WXUNUSED(event)) {
     wxPaintDC dc(this);
     const wxSize ClientSize = GetClientSize();
     
-    if (!visualDataQueue.empty()) {
-        SpectrumVisualData *vData;
-        
-        visualDataQueue.pop(vData);
-        
+    SpectrumVisualData *vData;
+    if (visualDataQueue.try_pop(vData)) {
+            
         if (vData) {
             spectrumPanel.setPoints(vData->spectrum_points);
             spectrumPanel.setPeakPoints(vData->spectrum_hold_points);

src/visual/WaterfallCanvas.cpp

@@ -95,8 +95,8 @@ void WaterfallCanvas::processInputQueue() {
         if (lpsIndex >= targetVis) {
             while (lpsIndex >= targetVis) {
                 SpectrumVisualData *vData;
-                if (!visualDataQueue.empty()) {
-                    visualDataQueue.pop(vData);
+
+                if (visualDataQueue.try_pop(vData)) {
                     
                     if (vData) {
                         if (vData->spectrum_points.size() == fft_size * 2) {
@@ -912,11 +912,13 @@ void WaterfallCanvas::updateCenterFrequency(long long freq) {
 
 void WaterfallCanvas::setLinesPerSecond(int lps) {
     std::lock_guard < std::mutex > lock(tex_update);
+    
     linesPerSecond = lps;
-    while (!visualDataQueue.empty()) {
-        SpectrumVisualData *vData;
-        visualDataQueue.pop(vData);
 
+    //empty all
+    SpectrumVisualData *vData;
+    while (visualDataQueue.try_pop(vData)) {
+        
         if (vData) {
             vData->decRefCount();
         }