blob: 2bdea027891587b8daec566dcbc3009d7dae3096 [file] [log] [blame]
// Copyright 2009 The RE2 Authors. All Rights Reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
#include "util/test.h"
#include "util/logging.h"
#include "re2/regexp.h"
#include "re2/walker-inl.h"
namespace re2 {
// Null walker. For benchmarking the walker itself.
class NullWalker : public Regexp::Walker<bool> {
NullWalker() {}
virtual bool PostVisit(Regexp* re, bool parent_arg, bool pre_arg,
bool* child_args, int nchild_args);
virtual bool ShortVisit(Regexp* re, bool a) {
// Should never be called: we use Walk(), not WalkExponential().
LOG(DFATAL) << "NullWalker::ShortVisit called";
return a;
NullWalker(const NullWalker&) = delete;
NullWalker& operator=(const NullWalker&) = delete;
// Called after visiting re's children. child_args contains the return
// value from each of the children's PostVisits (i.e., whether each child
// can match an empty string). Returns whether this clause can match an
// empty string.
bool NullWalker::PostVisit(Regexp* re, bool parent_arg, bool pre_arg,
bool* child_args, int nchild_args) {
return false;
// Returns whether re can match an empty string.
void Regexp::NullWalk() {
NullWalker w;
w.Walk(this, false);
} // namespace re2