eeschema: Check for proper type before dereference

When bundling a selection, we need to ensure that we have correct types
before attempting to dereference.

Fixes: lp:1841919
* https://bugs.launchpad.net/kicad/+bug/1841919

eeschema/sch_bitmap.h

@@ -78,6 +78,11 @@ public:
         m_image->SetScale( aScale );
     }
 
+    static inline bool ClassOf( const EDA_ITEM* aItem )
+    {
+        return aItem && SCH_BITMAP_T == aItem->Type();
+    }
+
     wxString GetClass() const override
     {
         return wxT( "SCH_BITMAP" );

eeschema/sch_bus_entry.h

@@ -132,6 +132,11 @@ public:
 
     ~SCH_BUS_WIRE_ENTRY() { }
 
+    static inline bool ClassOf( const EDA_ITEM* aItem )
+    {
+        return aItem && SCH_BUS_WIRE_ENTRY_T == aItem->Type();
+    }
+
     wxString GetClass() const override
     {
         return wxT( "SCH_BUS_WIRE_ENTRY" );
@@ -174,6 +179,11 @@ public:
 
     ~SCH_BUS_BUS_ENTRY() { }
 
+    static inline bool ClassOf( const EDA_ITEM* aItem )
+    {
+        return aItem && SCH_BUS_BUS_ENTRY_T == aItem->Type();
+    }
+
     wxString GetClass() const override
     {
         return wxT( "SCH_BUS_BUS_ENTRY" );

eeschema/sch_field.h

@@ -63,6 +63,11 @@ public:
 
     ~SCH_FIELD();
 
+    static inline bool ClassOf( const EDA_ITEM* aItem )
+    {
+        return aItem && SCH_FIELD_T == aItem->Type();
+    }
+
     wxString GetClass() const override
     {
         return wxT( "SCH_FIELD" );

eeschema/sch_junction.h

@@ -41,6 +41,11 @@ public:
 
     ~SCH_JUNCTION() { }
 
+    static inline bool ClassOf( const EDA_ITEM* aItem )
+    {
+        return aItem && SCH_JUNCTION_T == aItem->Type();
+    }
+
     wxString GetClass() const override
     {
         return wxT( "SCH_JUNCTION" );

eeschema/sch_line.h

@@ -57,6 +57,11 @@ public:
     SCH_LINE* Next() const { return (SCH_LINE*) Pnext; }
     SCH_LINE* Back() const { return (SCH_LINE*) Pback; }
 
+    static inline bool ClassOf( const EDA_ITEM* aItem )
+    {
+        return aItem && SCH_LINE_T == aItem->Type();
+    }
+
     wxString GetClass() const override
     {
         return wxT( "SCH_LINE" );

eeschema/sch_marker.h

@@ -38,6 +38,11 @@ public:
 
     // Do not create a copy constructor.  The one generated by the compiler is adequate.
 
+    static inline bool ClassOf( const EDA_ITEM* aItem )
+    {
+        return aItem && SCH_MARKER_T == aItem->Type();
+    }
+
     wxString GetClass() const override
     {
         return wxT( "SCH_MARKER" );

eeschema/sch_no_connect.h

@@ -46,6 +46,11 @@ public:
 
     ~SCH_NO_CONNECT() { }
 
+    static inline bool ClassOf( const EDA_ITEM* aItem )
+    {
+        return aItem && SCH_NO_CONNECT_T == aItem->Type();
+    }
+
     wxString GetClass() const override
     {
         return wxT( "SCH_NO_CONNECT" );

eeschema/sch_pin.h

@@ -49,6 +49,11 @@ public:
 
     SCH_PIN& operator=( const SCH_PIN& aPin );
 
+    static inline bool ClassOf( const EDA_ITEM* aItem )
+    {
+        return aItem && SCH_PIN_T == aItem->Type();
+    }
+
     wxString GetClass() const override
     {
         return wxT( "SCH_PIN" );

eeschema/sch_screen.h

@@ -105,6 +105,11 @@ public:
 
     DLIST< SCH_ITEM > & GetDrawList() { return m_drawList; }
 
+    static inline bool ClassOf( const EDA_ITEM* aItem )
+    {
+        return aItem && SCH_SCREEN_T == aItem->Type();
+    }
+
     virtual wxString GetClass() const override
     {
         return wxT( "SCH_SCREEN" );

eeschema/sch_sheet.h

@@ -91,6 +91,11 @@ public:
 
     ~SCH_SHEET_PIN() { }
 
+    static inline bool ClassOf( const EDA_ITEM* aItem )
+    {
+        return aItem && SCH_SHEET_PIN_T == aItem->Type();
+    }
+
     wxString GetClass() const override
     {
         return wxT( "SCH_SHEET_PIN" );
@@ -243,6 +248,11 @@ public:
 
     ~SCH_SHEET();
 
+    static inline bool ClassOf( const EDA_ITEM* aItem )
+    {
+        return aItem && SCH_SHEET_T == aItem->Type();
+    }
+
     wxString GetClass() const override
     {
         return wxT( "SCH_SHEET" );

eeschema/sch_text.h

@@ -93,6 +93,11 @@ public:
 
     ~SCH_TEXT() { }
 
+    static inline bool ClassOf( const EDA_ITEM* aItem )
+    {
+        return aItem && SCH_TEXT_T == aItem->Type();
+    }
+
     virtual wxString GetClass() const override
     {
         return wxT( "SCH_TEXT" );
@@ -217,6 +222,11 @@ public:
 
     ~SCH_LABEL() { }
 
+    static inline bool ClassOf( const EDA_ITEM* aItem )
+    {
+        return aItem && SCH_LABEL_T == aItem->Type();
+    }
+
     wxString GetClass() const override
     {
         return wxT( "SCH_LABEL" );
@@ -258,6 +268,11 @@ public:
 
     void Print( wxDC* DC, const wxPoint& offset ) override;
 
+    static inline bool ClassOf( const EDA_ITEM* aItem )
+    {
+        return aItem && SCH_GLOBAL_LABEL_T == aItem->Type();
+    }
+
     wxString GetClass() const override
     {
         return wxT( "SCH_GLOBALLABEL" );
@@ -303,6 +318,11 @@ public:
 
     void Print( wxDC* DC, const wxPoint& offset ) override;
 
+    static inline bool ClassOf( const EDA_ITEM* aItem )
+    {
+        return aItem && SCH_HIER_LABEL_T == aItem->Type();
+    }
+
     wxString GetClass() const override
     {
         return wxT( "SCH_HIERLABEL" );

eeschema/tools/ee_selection_tool.cpp

@@ -696,12 +696,13 @@ bool EE_SELECTION_TOOL::selectMultiple()
             view->Query( selectionBox, selectedItems );         // Get the list of selected items
 
             // Sheet pins aren't in the view; add them by hand
-            for( KIGFX::VIEW::LAYER_ITEM_PAIR& pair : selectedItems )
+            for( auto& pair : selectedItems )
             {
-                if( static_cast<EDA_ITEM*>( pair.first )->Type() == SCH_SHEET_T )
+                auto item = dynamic_cast<EDA_ITEM*>( pair.first );
+
+                if( auto sheet = dyn_cast<SCH_SHEET*>( item ) )
                 {
-                    SCH_SHEET* sheet = (SCH_SHEET*) pair.first;
-                    int        layer = pair.second;
+                    int layer = pair.second;
 
                     for( SCH_SHEET_PIN& pin : sheet->GetPins() )
                         selectedItems.emplace_back( KIGFX::VIEW::LAYER_ITEM_PAIR( &pin, layer ) );