Commit 8cdf078

@@ -0,0 +1,47 @@
+
+import 'package:blood_pressure_app/model/blood_pressure.dart';
+
+/// Indicate a possible error during record parsing.
+class RecordParsingResult {
+  RecordParsingResult._create(this._result, this._error);
+
+  final List<BloodPressureRecord>? _result;
+  final RecordParsingErrorType? _error;
+
+  /// Pass a valid record list and indicate success.
+  factory RecordParsingResult.ok(List<BloodPressureRecord> result)=>
+      RecordParsingResult._create(result, null);
+
+  /// Indicate a parsing failure.
+  factory RecordParsingResult.err(RecordParsingErrorType type)=>
+      RecordParsingResult._create(null, type);
+
+  /// Returns if there is an error present.
+  ///
+  /// Indicates that there is no result.
+  bool hasError() => _error != null;
+
+  /// Returns the passed list on success or the result of [errorHandler] in case a error is present.
+  ///
+  /// When [errorHandler] returns null a empty list is passed.
+  List<BloodPressureRecord> getOr(List<BloodPressureRecord>? Function(RecordParsingErrorType error) errorHandler) {
+    if (_result != null) {
+      assert(_error == null);
+      return _result!;
+    }
+    assert(_error != null);
+    return errorHandler(_error!) ?? [];
+  }
+}
+
+/// Indicates what type error occurred while trying to decode a csv data.
+enum RecordParsingErrorType {
+  /// There are not enough lines in the csv file to parse the record.
+  emptyFile,
+
+  formatNotReversible,
+
+  /// There is no column with this csv title.
+  unknownColumn
+  // TODO ...
+}
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