Function shiftDoc

src/codemirror.js:4487–4499

(doc, distance)

  // Sub-views need their line numbers shifted when text is added
  // above or below them in the parent document.
  function shiftDoc(doc, distance) {
    if (distance == 0) return;
    doc.first += distance;
    doc.sel = new Selection(map(doc.sel.ranges, function(range) {
      return new Range(Pos(range.anchor.line + distance, range.anchor.ch),
                       Pos(range.head.line + distance, range.head.ch));
    }), doc.sel.primIndex);
    if (doc.cm) {
      regChange(doc.cm, doc.first, doc.first - distance, distance);
      for (var d = doc.cm.display, l = d.viewFrom; l < d.viewTo; l++)
        regLineChange(doc.cm, l, "gutter");
    }
  }

  // More lower-level change function, handling only a single document
  // (not linked ones).