Replace RE2 import with a dependency

third_party/re2/re2/filtered_re2.h

-// 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.
-
-// The class FilteredRE2 is used as a wrapper to multiple RE2 regexps.
-// It provides a prefilter mechanism that helps in cutting down the
-// number of regexps that need to be actually searched.
-//
-// By design, it does not include a string matching engine. This is to
-// allow the user of the class to use their favorite string match
-// engine. The overall flow is: Add all the regexps using Add, then
-// Compile the FilteredRE2. The compile returns strings that need to
-// be matched. Note that all returned strings are lowercase. For
-// applying regexps to a search text, the caller does the string
-// matching using the strings returned. When doing the string match,
-// note that the caller has to do that on lower cased version of the
-// search text. Then call FirstMatch or AllMatches with a vector of
-// indices of strings that were found in the text to get the actual
-// regexp matches.
-
-#ifndef RE2_FILTERED_RE2_H_
-#define RE2_FILTERED_RE2_H_
-
-#include <vector>
-#include "re2/re2.h"
-
-namespace re2 {
-using std::vector;
-
-class PrefilterTree;
-
-class FilteredRE2 {
- public:
-  FilteredRE2();
-  ~FilteredRE2();
-
-  // Uses RE2 constructor to create a RE2 object (re). Returns
-  // re->error_code(). If error_code is other than NoError, then re is
-  // deleted and not added to re2_vec_.
-  RE2::ErrorCode Add(const StringPiece& pattern,
-                     const RE2::Options& options,
-                     int *id);
-
-  // Prepares the regexps added by Add for filtering.  Returns a set
-  // of strings that the caller should check for in candidate texts.
-  // The returned strings are lowercased. When doing string matching,
-  // the search text should be lowercased first to find matching
-  // strings from the set of strings returned by Compile.  Call after
-  // all Add calls are done.
-  void Compile(vector<string>* strings_to_match);
-
-  // Returns the index of the first matching regexp.
-  // Returns -1 on no match. Can be called prior to Compile.
-  // Does not do any filtering: simply tries to Match the
-  // regexps in a loop.
-  int SlowFirstMatch(const StringPiece& text) const;
-
-  // Returns the index of the first matching regexp.
-  // Returns -1 on no match. Compile has to be called before
-  // calling this.
-  int FirstMatch(const StringPiece& text,
-                 const vector<int>& atoms) const;
-
-  // Returns the indices of all matching regexps, after first clearing
-  // matched_regexps.
-  bool AllMatches(const StringPiece& text,
-                  const vector<int>& atoms,
-                  vector<int>* matching_regexps) const;
-
-  // Returns the indices of all potentially matching regexps after first
-  // clearing potential_regexps.
-  // A regexp is potentially matching if it passes the filter.
-  // If a regexp passes the filter it may still not match.
-  // A regexp that does not pass the filter is guaranteed to not match.
-  void AllPotentials(const vector<int>& atoms,
-                     vector<int>* potential_regexps) const;
-
-  // The number of regexps added.
-  int NumRegexps() const { return static_cast<int>(re2_vec_.size()); }
-
- private:
-
-  // Get the individual RE2 objects. Useful for testing.
-  RE2* GetRE2(int regexpid) const { return re2_vec_[regexpid]; }
-
-  // Print prefilter.
-  void PrintPrefilter(int regexpid);
-
-  // Useful for testing and debugging.
-  void RegexpsGivenStrings(const vector<int>& matched_atoms,
-                           vector<int>* passed_regexps);
-
-  // All the regexps in the FilteredRE2.
-  vector<RE2*> re2_vec_;
-
-  // Has the FilteredRE2 been compiled using Compile()
-  bool compiled_;
-
-  // An AND-OR tree of string atoms used for filtering regexps.
-  PrefilterTree* prefilter_tree_;
-
-  //DISALLOW_COPY_AND_ASSIGN(FilteredRE2);
-  FilteredRE2(const FilteredRE2&);
-  void operator=(const FilteredRE2&);
-};
-
-}  // namespace re2
-
-#endif  // RE2_FILTERED_RE2_H_