Add Contains search to SCHEMATIC

eeschema/schematic.cpp

@@ -216,6 +216,25 @@ void SCHEMATIC::CacheExistingAnnotation()
 }
 
 
+bool SCHEMATIC::Contains( const SCH_REFERENCE& aRef ) const
+{
+    SCH_SHEET_LIST sheets = Hierarchy();
+    SCH_REFERENCE_LIST references;
+
+    /// TODO(snh): This is horribly inefficient, we should be using refdesTracker for this.
+    /// REFDES_TRACKER will need to be extended to track if a reference is currently present in the schematic
+    /// as well as the units.  For now, this is relatively fast for reasonably sized schematics
+    /// Famous last words...
+    sheets.GetSymbols( references );
+
+    return std::any_of( references.begin(), references.end(),
+                        [&]( const SCH_REFERENCE& ref )
+                        {
+                            return ref.GetFullRef( true ) == aRef.GetFullRef( true );
+                        } );
+}
+
+
 void SCHEMATIC::SetRoot( SCH_SHEET* aRootSheet )
 {
     wxCHECK_RET( aRootSheet, wxS( "Call to SetRoot with null SCH_SHEET!" ) );

eeschema/schematic.h

@@ -39,6 +39,7 @@ class SCH_SCREEN;
 class SCH_SHEET;
 class SCH_SHEET_LIST;
 class SCH_GLOBALLABEL;
+class SCH_REFERENCE;
 class PROGRESS_REPORTER;
 class TOOL_MANAGER;
 class PICKED_ITEMS_LIST;
@@ -432,6 +433,14 @@ public:
      */
     void CacheExistingAnnotation();
 
+    /**
+     * Check if the schematic contains the specified reference.
+     *
+     * @param aRef is the reference to check for.
+     * @return true if the schematic contains the reference, false otherwise.
+     */
+    bool Contains( const SCH_REFERENCE& aRef ) const;
+
     /**
      * True if a SCHEMATIC exists, false if not
      */