Implementation of a Matching strategy for URLs in the Declarative WebRequest API.

chrome/browser/extensions/api/declarative/substring_set_matcher.h

+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_SUBSTRING_SET_MATCHER_H_
+#define CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_SUBSTRING_SET_MATCHER_H_
+#pragma once
+
+#include <map>
+#include <set>
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+
+namespace extensions {
+
+// An individual pattern of the SubstringSetMatcher. A pattern consists of
+// a string (interpreted as individual bytes, no character encoding) and an
+// identifier.
+// Each pattern that matches a string emits its ID to the caller of
+// SubstringSetMatcher::Match(). This helps the caller to figure out what
+// patterns matched a string. All patterns registered to a SubstringSetMatcher
+// need to contain unique IDs.
+class SubstringPattern {
+ public:
+  typedef int ID;
+
+  SubstringPattern(const std::string& pattern, ID id);
+  const std::string& pattern() const { return pattern_; }
+  ID id() const { return id_; }
+
+ private:
+  std::string pattern_;
+  ID id_;
+
+  DISALLOW_COPY_AND_ASSIGN(SubstringPattern);
+};
+
+// Class that store a set of string patterns and can find for a string S,
+// which string patterns occur in S.
+class SubstringSetMatcher {
+ public:
+  SubstringSetMatcher();
+  ~SubstringSetMatcher();
+
+  // Registers all |patterns| and takes ownership.
+  // The same pattern cannot be registered twice and each pattern needs to have
+  // a unique ID.
+  // Ownership of the patterns remains with the caller.
+  void RegisterPatterns(const std::vector<const SubstringPattern*>& patterns);
+
+  // Unregisters the passed |patterns| and destroys them.
+  void UnregisterPatterns(const std::vector<const SubstringPattern*>& patterns);
+
+  // Analogous to RegisterPatterns and UnregisterPatterns but executes both
+  // operations in one step, which may be cheaper in the execution.
+  void RegisterAndUnregisterPatterns(
+      const std::vector<const SubstringPattern*>& to_register,
+      const std::vector<const SubstringPattern*>& to_unregister);
+
+  // Matches |text| against all registered SubstringPatterns. Stores the IDs
+  // of matching patterns in |matches|.
+  bool Match(const std::string& text,
+             std::set<SubstringPattern::ID>* matches) const;
+
+ private:
+  typedef std::map<SubstringPattern::ID, const SubstringPattern*>
+      SubstringPatternSet;
+  SubstringPatternSet patterns_;
+
+  DISALLOW_COPY_AND_ASSIGN(SubstringSetMatcher);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_API_DECLARATIVE_SUBSTRING_SET_MATCHER_H_