Prevent duplicate sheet names in schematic editor.

eeschema/sch_screen.cpp

@@ -675,6 +675,23 @@ LIB_PIN* SCH_SCREEN::GetPin( const wxPoint& aPosition, SCH_COMPONENT** aComponen
 }
 
 
+SCH_SHEET* SCH_SCREEN::GetSheet( const wxString& aName )
+{
+    for( SCH_ITEM* item = GetDrawItems(); item != NULL; item = item->Next() )
+    {
+        if( item->Type() != SCH_SHEET_T )
+            continue;
+
+        SCH_SHEET* sheet = (SCH_SHEET*) item;
+
+        if( aName.CmpNoCase( sheet->m_SheetName ) == 0 )
+            return sheet;
+    }
+
+    return NULL;
+}
+
+
 SCH_SHEET_PIN* SCH_SCREEN::GetSheetLabel( const wxPoint& aPosition )
 {
     SCH_SHEET_PIN* sheetPin = NULL;

eeschema/sheet.cpp

@@ -65,6 +65,16 @@ bool SCH_EDIT_FRAME::EditSheet( SCH_SHEET* aSheet, wxDC* aDC )
         return false;
     }
 
+    // Duplicate sheet names are not valid.
+    const SCH_SHEET* sheet = GetScreen()->GetSheet( dlg.GetSheetName() );
+
+    if( (sheet != NULL) && (sheet != aSheet) )
+    {
+        DisplayError( this, wxString::Format( _( "A sheet named \"%s\" already exists." ),
+                                              GetChars( dlg.GetSheetName() ) ) );
+        return false;
+    }
+
     wxString msg;
     wxString tmp;
     bool loadFromFile = false;

include/class_sch_screen.h

@@ -305,6 +305,16 @@ public:
     LIB_PIN* GetPin( const wxPoint& aPosition, SCH_COMPONENT** aComponent = NULL,
                      bool aEndPointOnly = false ) const;
 
+    /**
+     * Function GetSheet
+     * returns a sheet object pointer that is named \a aName.
+     *
+     * @note The screen hierarchy is not descened.
+     * @param aName is the case insensitive name of the sheet.
+     * @return A pointer to the SCH_SHEET object found or NULL.
+     */
+    SCH_SHEET* GetSheet( const wxString& aName );
+
     /**
      * Function GetSheetLabel
      * test the screen if \a aPosition is a sheet label object.