// convertWithVisitorHelper converts HTML with visitor support.
// Called by Convert() when options.Visitor is not nil.
// Returns the ConversionResult or an error.
func convertWithVisitorHelper(html string, options *ConversionOptions, visitor Visitor) (*ConversionResult, error) {
cHTML := C.CString(html)
defer C.free(unsafe.Pointer(cHTML))
var cOptions *C.{{ conversion_options_type }}
if options != nil {
optionsBytes, err := json.Marshal(options)
if err != nil {
return nil, fmt.Errorf("failed to marshal options: %w", err)
}
optionsJSON := C.CString(string(optionsBytes))
defer C.free(unsafe.Pointer(optionsJSON))
cOptions = C.{{ fn_options_from_json }}(optionsJSON)
defer C.{{ fn_options_free }}(cOptions)
}
if cOptions == nil {
// Allocate a default options struct so we can attach the visitor.
defaultJSON := C.CString("{}")
cOptions = C.{{ fn_options_from_json }}(defaultJSON)
C.free(unsafe.Pointer(defaultJSON))
defer C.{{ fn_options_free }}(cOptions)
}
// Register visitor and build the C VTable via the static C helper.
id := registerVisitor(visitor)
defer unregisterVisitor(id)
vtbl := C.makeVisitorVTable()
// Create a bridge that holds the VTable and the visitor ID as user_data.
bridge := C.{{ fn_bridge_new }}(&vtbl, unsafe.Pointer(id))
if bridge == nil {
return nil, fmt.Errorf("failed to create visitor bridge")
}
defer C.{{ fn_bridge_free }}(bridge)
// Attach the bridge to the options struct so convert() picks it up.
C.{{ fn_options_set_visitor }}(cOptions, (*C.{{ bridge_c_type }})(bridge))
ptr := C.{{ fn_convert }}(cHTML, cOptions)
if ptr == nil {
if err := lastError(); err != nil {
return nil, err
}
return nil, fmt.Errorf("conversion returned nil")
}
defer C.{{ fn_result_free }}(ptr)
jsonPtr := C.{{ fn_result_to_json }}(ptr)
if jsonPtr == nil {
return nil, fmt.Errorf("conversion result serialisation failed")
}
defer C.free(unsafe.Pointer(jsonPtr))
var result ConversionResult
if err := json.Unmarshal([]byte(C.GoString(jsonPtr)), &result); err != nil {
return nil, fmt.Errorf("failed to decode conversion result: %w", err)
}
return &result, nil
}