Method key

basex-core/src/main/java/org/basex/query/expr/CmpR.java:259–282

Retrieves the statistics key for the element/attribute name. @param ii index info @param type index type @return key, or null if statistics are not available

(final IndexInfo ii, final IndexType type)

   * @return key, or {@code null} if statistics are not available
   */
  private Stats key(final IndexInfo ii, final IndexType type) {
    // statistics are not up-to-date
    final Data data = ii.db.data();
    if(data == null || !data.meta.uptodate || !data.nspaces.isEmpty() ||
        !(expr instanceof final AxisPath path)) return null;

    NameTest test = ii.test;
    if(test == null) {
      final Step step;
      final int st = path.steps.length - 1;
      if(type == IndexType.TEXT) {
        step = st == 0 ? ii.step : path.step(st - 1);
      } else {
        step = path.step(st);
        if(step.axis != Axis.ATTRIBUTE || step.exprs.length > 0) return null;
      }
      if(!(step.test instanceof final NameTest nt) || nt.name == null) return null;
      test = nt;
    }

    final Names names = type == IndexType.TEXT ? data.elemNames : data.attrNames;
    final Stats stats = names.stats(names.index(test.qname.local()));
    return stats != null && StatsType.isNumeric(stats.type) ? stats : null;
  }

  @Override
  public Expr copy(final CompileContext cc, final IntObjectMap<Var> vm) {