Function add

lib/web/CodeMirror/keymap/vim.js:549–575

(cm, oldCur, newCur)

      var tail = 0;
      var buffer = new Array(size);
      function add(cm, oldCur, newCur) {
        var current = pointer % size;
        var curMark = buffer[current];
        function useNextSlot(cursor) {
          var next = ++pointer % size;
          var trashMark = buffer[next];
          if (trashMark) {
            trashMark.clear();
          }
          buffer[next] = cm.setBookmark(cursor);
        }
        if (curMark) {
          var markPos = curMark.find();
          // avoid recording redundant cursor position
          if (markPos && !cursorEqual(markPos, oldCur)) {
            useNextSlot(oldCur);
          }
        } else {
          useNextSlot(oldCur);
        }
        useNextSlot(newCur);
        head = pointer;
        tail = pointer - size + 1;
        if (tail < 0) {
          tail = 0;
        }
      }
      function move(cm, offset) {
        pointer += offset;
        if (pointer > head) {