1 // Copyright 2009 The RE2 Authors. All Rights Reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 // Prefilter is the class used to extract string guards from regexps. 6 // Rather than using Prefilter class directly, use FilteredRE2. 7 // See filtered_re2.h 8 9 #ifndef RE2_PREFILTER_H_ 10 #define RE2_PREFILTER_H_ 11 12 #include "util/util.h" 13 14 namespace re2 { 15 16 class RE2; 17 18 class Regexp; 19 20 class Prefilter { 21 // Instead of using Prefilter directly, use FilteredRE2; see filtered_re2.h 22 public: 23 enum Op { 24 ALL = 0, // Everything matches 25 NONE, // Nothing matches 26 ATOM, // The string atom() must match 27 AND, // All in subs() must match 28 OR, // One of subs() must match 29 }; 30 31 explicit Prefilter(Op op); 32 ~Prefilter(); 33 34 Op op() { return op_; } 35 const string& atom() const { return atom_; } 36 void set_unique_id(int id) { unique_id_ = id; } 37 int unique_id() const { return unique_id_; } 38 39 // The children of the Prefilter node. 40 vector<Prefilter*>* subs() { 41 CHECK(op_ == AND || op_ == OR); 42 return subs_; 43 } 44 45 // Set the children vector. Prefilter takes ownership of subs and 46 // subs_ will be deleted when Prefilter is deleted. 47 void set_subs(vector<Prefilter*>* subs) { subs_ = subs; } 48 49 // Given a RE2, return a Prefilter. The caller takes ownership of 50 // the Prefilter and should deallocate it. Returns NULL if Prefilter 51 // cannot be formed. 52 static Prefilter* FromRE2(const RE2* re2); 53 54 // Returns a readable debug string of the prefilter. 55 string DebugString() const; 56 57 private: 58 class Info; 59 60 // Combines two prefilters together to create an AND. The passed 61 // Prefilters will be part of the returned Prefilter or deleted. 62 static Prefilter* And(Prefilter* a, Prefilter* b); 63 64 // Combines two prefilters together to create an OR. The passed 65 // Prefilters will be part of the returned Prefilter or deleted. 66 static Prefilter* Or(Prefilter* a, Prefilter* b); 67 68 // Generalized And/Or 69 static Prefilter* AndOr(Op op, Prefilter* a, Prefilter* b); 70 71 static Prefilter* FromRegexp(Regexp* a); 72 73 static Prefilter* FromString(const string& str); 74 75 static Prefilter* OrStrings(set<string>* ss); 76 77 static Info* BuildInfo(Regexp* re); 78 79 Prefilter* Simplify(); 80 81 // Kind of Prefilter. 82 Op op_; 83 84 // Sub-matches for AND or OR Prefilter. 85 vector<Prefilter*>* subs_; 86 87 // Actual string to match in leaf node. 88 string atom_; 89 90 // If different prefilters have the same string atom, or if they are 91 // structurally the same (e.g., OR of same atom strings) they are 92 // considered the same unique nodes. This is the id for each unique 93 // node. This field is populated with a unique id for every node, 94 // and -1 for duplicate nodes. 95 int unique_id_; 96 97 // Used for debugging, helps in tracking memory leaks. 98 int alloc_id_; 99 100 DISALLOW_EVIL_CONSTRUCTORS(Prefilter); 101 }; 102 103 } // namespace re2 104 105 #endif // RE2_PREFILTER_H_ 106
