API: Add symbol path for footprint instances

See https://gitlab.com/kicad/code/kicad-python/-/issues/37

api/proto/board/board_types.proto

@@ -960,4 +960,7 @@ message FootprintInstance
 
   FootprintAttributes attributes = 11;
   FootprintDesignRuleOverrides overrides  = 12;
+
+  // The sheet path to the associated symbol for this footprint instance, if one exists
+  kiapi.common.types.SheetPath symbol_path = 13;
 }

common/api/api_utils.cpp

@@ -21,6 +21,7 @@
 #include <magic_enum.hpp>
 #include <api/api_utils.h>
 #include <geometry/shape_poly_set.h>
+#include <kiid.h>
 #include <wx/log.h>
 
 const wxChar* const traceApi = wxT( "KICAD_API" );
@@ -232,4 +233,14 @@ KICOMMON_API KIGFX::COLOR4D UnpackColor( const types::Color& aInput )
     return KIGFX::COLOR4D( r, g, b, a );
 }
 
+KICOMMON_API void PackSheetPath( types::SheetPath& aOutput, const KIID_PATH& aInput )
+{
+    aOutput.clear_path();
+
+    for( const KIID& entry : aInput )
+        aOutput.add_path()->set_value( entry.AsStdString() );
+
+    aOutput.set_path_human_readable( aInput.AsString().ToStdString() );
+}
+
 } // namespace kiapi::common

include/api/api_utils.h

@@ -34,6 +34,7 @@
 #include <gal/color4d.h>
 
 class SHAPE_LINE_CHAIN;
+class KIID_PATH;
 
 /**
  * Flag to enable debug output related to the IPC API and its plugin system
@@ -77,6 +78,8 @@ KICOMMON_API void PackColor( types::Color& aOutput, const KIGFX::COLOR4D& aInput
 
 KICOMMON_API KIGFX::COLOR4D UnpackColor( const types::Color& aInput );
 
+KICOMMON_API void PackSheetPath( types::SheetPath& aOutput, const KIID_PATH& aInput );
+
 } // namespace kiapi::common
 
 #endif //KICAD_API_UTILS_H

pcbnew/footprint.cpp

@@ -389,6 +389,9 @@ void FOOTPRINT::Serialize( google::protobuf::Any &aContainer ) const
         itemMsg->PackFrom( modelMsg );
     }
 
+    // Serialized only (can't modify this from the API to change the symbol mapping)
+    kiapi::common::PackSheetPath( *footprint.mutable_symbol_path(), m_path );
+
     aContainer.PackFrom( footprint );
 }