feat(TextDocument): add utility function for getting a position from an offset

Author: lheckemann

pygls/workspace/text_document.py

@@ -192,6 +192,14 @@ def offset_at_position(self, client_position: types.Position) -> int:
         )
         return self.offset_at_server_position(server_position)
 
+    def position_at_offset(self, offset: int) -> ServerPosition:
+        remaining_offset = offset
+        for lineno, line in enumerate(self.lines):
+            if remaining_offset < len(line):
+                return ServerPosition(lineno, remaining_offset)
+            remaining_offset -= len(line)
+        return ServerPosition(lineno, len(line))
+
     def range_from_client_units(self, range: types.Range) -> ServerRange:
         """
         Convert a range from client units into code points, suitable for indexing into `self.lines`.