WIP: fixed a basic issue with empty layers

Previous: empty layers occupied a special layer in the DSS
But what when empty layers are required as outputs?
ONE layer isn't good -> would overwrite the layer and it's
no longer empty for others.
So we need to keep the layers separate.

src/db/db/dbDeepShapeStore.cc

@@ -222,24 +222,11 @@ DeepLayer::check_dss () const
 struct DeepShapeStore::LayoutHolder
 {
   LayoutHolder (const db::ICplxTrans &trans)
-    : refs (0), layout (false), builder (&layout, trans), m_empty_layer (std::numeric_limits<unsigned int>::max ())
+    : refs (0), layout (false), builder (&layout, trans)
   {
     //  .. nothing yet ..
   }
 
-  unsigned int empty_layer () const
-  {
-    if (m_empty_layer == std::numeric_limits<unsigned int>::max ()) {
-      const_cast<LayoutHolder *> (this)->make_empty_layer ();
-    }
-    return m_empty_layer;
-  }
-
-  unsigned int new_empty_layer ()
-  {
-    return layout.insert_layer ();
-  }
-
   void add_layer_ref (unsigned int layer)
   {
     layer_refs [layer] += 1;
@@ -260,15 +247,6 @@ struct DeepShapeStore::LayoutHolder
   db::Layout layout;
   db::HierarchyBuilder builder;
   std::map<unsigned int, int> layer_refs;
-
-private:
-  unsigned int m_empty_layer;
-
-  void make_empty_layer ()
-  {
-    m_empty_layer = layout.insert_layer ();
-    layer_refs [m_empty_layer] += 1;  //  the empty layer is not deleted
-  }
 };
 
 // ----------------------------------------------------------------------------------
@@ -571,28 +549,6 @@ DeepLayer DeepShapeStore::create_polygon_layer (const db::RecursiveShapeIterator
   return DeepLayer (this, layout_index, layer_index);
 }
 
-DeepLayer DeepShapeStore::empty_layer (unsigned int layout_index) const
-{
-  return DeepLayer (const_cast<DeepShapeStore *> (this), layout_index, m_layouts[layout_index]->empty_layer ());
-}
-
-DeepLayer DeepShapeStore::empty_layer () const
-{
-  require_singular ();
-  return empty_layer (0);
-}
-
-DeepLayer DeepShapeStore::new_empty_layer (unsigned int layout_index) const
-{
-  return DeepLayer (const_cast<DeepShapeStore *> (this), layout_index, m_layouts[layout_index]->new_empty_layer ());
-}
-
-DeepLayer DeepShapeStore::new_empty_layer () const
-{
-  require_singular ();
-  return new_empty_layer (0);
-}
-
 DeepLayer DeepShapeStore::create_custom_layer (const db::RecursiveShapeIterator &si, HierarchyBuilderShapeReceiver *pipe, const db::ICplxTrans &trans)
 {
   unsigned int layout_index = layout_for_iter (si, trans);

src/db/db/dbDeepShapeStore.h

@@ -343,32 +343,6 @@ public:
    */
   DeepLayer create_copy (const DeepLayer &source, HierarchyBuilderShapeReceiver *pipe);
 
-  /**
-   *  @brief Gets the empty working layer
-   *
-   *  This method will deliver an empty layer for the given layout index. CAUTION: don't modify this layer as it may
-   *  be reused.
-   */
-  DeepLayer empty_layer (unsigned int layout_index) const;
-
-  /**
-   *  @brief Gets the empty working layer for the singular layout
-   */
-  DeepLayer empty_layer () const;
-
-  /**
-   *  @brief Gets a new empty working layer
-   *
-   *  This method will deliver an empty layer for the given layout index. This layer is a fresh one and can be
-   *  modified.
-   */
-  DeepLayer new_empty_layer (unsigned int layout_index) const;
-
-  /**
-   *  @brief Gets a new empty working layer for the singular layout
-   */
-  DeepLayer new_empty_layer () const;
-
   /**
    *  @brief Inserts the deep layer's shapes into some target layout
    */

src/db/db/dbLayoutToNetlist.cc

@@ -337,11 +337,7 @@ void LayoutToNetlist::register_layer (const db::Region &region, const std::strin
     db::DeepRegion *delegate = dynamic_cast<db::DeepRegion *> (region.delegate());
     if (! delegate) {
 
-      if (region.empty ()) {
-        dl = dss ().empty_layer (m_layout_index);
-      } else {
-        dl = dss ().create_from_flat (region, true);
-      }
+      dl = dss ().create_from_flat (region, true);
 
     } else {
 
@@ -436,9 +432,6 @@ db::DeepLayer LayoutToNetlist::deep_layer_of (const db::Region &region) const
     std::pair<bool, db::DeepLayer> lff = dss ().layer_for_flat (region);
     if (lff.first) {
       return lff.second;
-    } else if (region.empty ()) {
-      //  provide a substitute empty layer for empty
-      return dss ().empty_layer (m_layout_index);
     } else {
       throw (tl::Exception (tl::to_string (tr ("Non-hierarchical layers cannot be used in netlist extraction"))));
     }

src/db/db/dbNetlistDeviceExtractor.cc

@@ -167,10 +167,6 @@ void NetlistDeviceExtractor::extract (db::DeepShapeStore &dss, unsigned int layo
       if (alias.first) {
         //  use deep layer alias for a given flat one (if found)
         layers.push_back (alias.second.layer ());
-      } else if (l->second->empty ()) {
-        //  provide a substitute empty layer (CAUTION: we can't use the
-        //  singleton "empty_layer" because this may be used as OUTPUT).
-        layers.push_back (dss.new_empty_layer (layout_index).layer ());
       } else {
         throw tl::Exception (tl::sprintf (tl::to_string (tr ("Invalid region passed to input layer '%s' for device extraction (device %s): must be of deep region kind")), ld->name, name ()));
       }

src/db/unit_tests/dbNetlistExtractorTests.cc

@@ -1136,7 +1136,7 @@ TEST(5_ResAndCapWithBulkExtraction)
   db::Region rmetal2_lbl (db::RecursiveShapeIterator (ly, tc, metal2_lbl), dss);
   db::Region rcap (db::RecursiveShapeIterator (ly, tc, cap), dss);
   db::Region rres (db::RecursiveShapeIterator (ly, tc, res), dss);
-  db::Region rbulk (new db::DeepRegion (dss.empty_layer ()));
+  db::Region rbulk;
 
   //  derived regions
 
@@ -1409,7 +1409,7 @@ TEST(6_BJT3TransistorExtraction)
   db::Region rmetal2_lbl (db::RecursiveShapeIterator (ly, tc, metal2_lbl), dss);
   db::Region rpplus (db::RecursiveShapeIterator (ly, tc, pplus), dss);
   db::Region rnplus (db::RecursiveShapeIterator (ly, tc, nplus), dss);
-  db::Region rbulk (new db::DeepRegion (dss.empty_layer ()));
+  db::Region rbulk;
 
   //  derived regions
 

src/laybasic/laybasic/layNetlistBrowserPage.cc

@@ -1155,19 +1155,19 @@ void
 NetlistBrowserPage::configure_marker (Marker *marker, bool with_fill)
 {
   if (m_marker_line_width >= 0) {
-    mp_markers.back ()->set_line_width (m_marker_line_width);
+    marker->set_line_width (m_marker_line_width);
   }
 
   if (m_marker_vertex_size >= 0) {
-    mp_markers.back ()->set_vertex_size (m_marker_vertex_size);
+    marker->set_vertex_size (m_marker_vertex_size);
   }
 
   if (m_marker_halo >= 0) {
-    mp_markers.back ()->set_halo (m_marker_halo);
+    marker->set_halo (m_marker_halo);
   }
 
   if (m_marker_dither_pattern >= 0 && with_fill) {
-    mp_markers.back ()->set_dither_pattern (m_marker_dither_pattern);
+    marker->set_dither_pattern (m_marker_dither_pattern);
   }
 }