Include RE2 library

third_party/re2/re2/prefilter.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.
+
+// Prefilter is the class used to extract string guards from regexps.
+// Rather than using Prefilter class directly, use FilteredRE2.
+// See filtered_re2.h
+
+#ifndef RE2_PREFILTER_H_
+#define RE2_PREFILTER_H_
+
+#include "util/util.h"
+
+namespace re2 {
+
+class RE2;
+
+class Regexp;
+
+class Prefilter {
+  // Instead of using Prefilter directly, use FilteredRE2; see filtered_re2.h
+ public:
+  enum Op {
+    ALL = 0,  // Everything matches
+    NONE,  // Nothing matches
+    ATOM,  // The string atom() must match
+    AND,   // All in subs() must match
+    OR,   // One of subs() must match
+  };
+
+  explicit Prefilter(Op op);
+  ~Prefilter();
+
+  Op op() { return op_; }
+  const string& atom() const { return atom_; }
+  void set_unique_id(int id) { unique_id_ = id; }
+  int unique_id() const { return unique_id_; }
+
+  // The children of the Prefilter node.
+  vector<Prefilter*>* subs() {
+    CHECK(op_ == AND || op_ == OR);
+    return subs_;
+  }
+
+  // Set the children vector. Prefilter takes ownership of subs and
+  // subs_ will be deleted when Prefilter is deleted.
+  void set_subs(vector<Prefilter*>* subs) { subs_ = subs; }
+
+  // Given a RE2, return a Prefilter. The caller takes ownership of
+  // the Prefilter and should deallocate it. Returns NULL if Prefilter
+  // cannot be formed.
+  static Prefilter* FromRE2(const RE2* re2);
+
+  // Returns a readable debug string of the prefilter.
+  string DebugString() const;
+
+ private:
+  class Info;
+
+  // Combines two prefilters together to create an AND. The passed
+  // Prefilters will be part of the returned Prefilter or deleted.
+  static Prefilter* And(Prefilter* a, Prefilter* b);
+
+  // Combines two prefilters together to create an OR. The passed
+  // Prefilters will be part of the returned Prefilter or deleted.
+  static Prefilter* Or(Prefilter* a, Prefilter* b);
+
+  // Generalized And/Or
+  static Prefilter* AndOr(Op op, Prefilter* a, Prefilter* b);
+
+  static Prefilter* FromRegexp(Regexp* a);
+
+  static Prefilter* FromString(const string& str);
+
+  static Prefilter* OrStrings(set<string>* ss);
+
+  static Info* BuildInfo(Regexp* re);
+
+  Prefilter* Simplify();
+
+  // Kind of Prefilter.
+  Op op_;
+
+  // Sub-matches for AND or OR Prefilter.
+  vector<Prefilter*>* subs_;
+
+  // Actual string to match in leaf node.
+  string atom_;
+
+  // If different prefilters have the same string atom, or if they are
+  // structurally the same (e.g., OR of same atom strings) they are
+  // considered the same unique nodes. This is the id for each unique
+  // node. This field is populated with a unique id for every node,
+  // and -1 for duplicate nodes.
+  int unique_id_;
+
+  // Used for debugging, helps in tracking memory leaks.
+  int alloc_id_;
+
+  DISALLOW_EVIL_CONSTRUCTORS(Prefilter);
+};
+
+}  // namespace re2
+
+#endif  // RE2_PREFILTER_H_