1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef EXTENSIONS_COMMON_EVENT_FILTER_H_
6#define EXTENSIONS_COMMON_EVENT_FILTER_H_
7
8#include <map>
9#include <set>
10
11#include "base/memory/linked_ptr.h"
12#include "components/url_matcher/url_matcher.h"
13#include "extensions/common/event_filtering_info.h"
14#include "extensions/common/event_matcher.h"
15
16namespace extensions {
17
18// Matches incoming events against a collection of EventMatchers. Each added
19// EventMatcher is given an id which is returned by MatchEvent() when it is
20// passed a matching event.
21class EventFilter {
22 public:
23  typedef int MatcherID;
24  EventFilter();
25  ~EventFilter();
26
27  // Adds an event matcher that will be used in calls to MatchEvent(). Returns
28  // the id of the matcher, or -1 if there was an error.
29  MatcherID AddEventMatcher(const std::string& event_name,
30                            scoped_ptr<EventMatcher> matcher);
31
32  // Retrieve the EventMatcher with the given id.
33  EventMatcher* GetEventMatcher(MatcherID id);
34
35  // Retrieve the name of the event that the EventMatcher specified by |id| is
36  // referring to.
37  const std::string& GetEventName(MatcherID id);
38
39  // Removes an event matcher, returning the name of the event that it was for.
40  std::string RemoveEventMatcher(MatcherID id);
41
42  // Match an event named |event_name| with filtering info |event_info| against
43  // our set of event matchers. Returns a set of ids that correspond to the
44  // event matchers that matched the event.
45  // TODO(koz): Add a std::string* parameter for retrieving error messages.
46  std::set<MatcherID> MatchEvent(const std::string& event_name,
47                                 const EventFilteringInfo& event_info,
48                                 int routing_id);
49
50  int GetMatcherCountForEvent(const std::string& event_name);
51
52  // For testing.
53  bool IsURLMatcherEmpty() const {
54    return url_matcher_.IsEmpty();
55  }
56
57 private:
58  class EventMatcherEntry {
59   public:
60    // Adds |condition_sets| to |url_matcher| on construction and removes them
61    // again on destruction. |condition_sets| should be the
62    // URLMatcherConditionSets that match the URL constraints specified by
63    // |event_matcher|.
64    EventMatcherEntry(
65        scoped_ptr<EventMatcher> event_matcher,
66        url_matcher::URLMatcher* url_matcher,
67        const url_matcher::URLMatcherConditionSet::Vector& condition_sets);
68    ~EventMatcherEntry();
69
70    // Prevents the removal of condition sets when this class is destroyed. We
71    // call this in EventFilter's destructor so that we don't do the costly
72    // removal of condition sets when the URLMatcher is going to be destroyed
73    // and clean them up anyway.
74    void DontRemoveConditionSetsInDestructor();
75
76    EventMatcher* event_matcher() {
77      return event_matcher_.get();
78    }
79
80   private:
81    scoped_ptr<EventMatcher> event_matcher_;
82    // The id sets in url_matcher_ that this EventMatcher owns.
83    std::vector<url_matcher::URLMatcherConditionSet::ID> condition_set_ids_;
84    url_matcher::URLMatcher* url_matcher_;
85
86    DISALLOW_COPY_AND_ASSIGN(EventMatcherEntry);
87  };
88
89  // Maps from a matcher id to an event matcher entry.
90  typedef std::map<MatcherID, linked_ptr<EventMatcherEntry> > EventMatcherMap;
91
92  // Maps from event name to the map of matchers that are registered for it.
93  typedef std::map<std::string, EventMatcherMap> EventMatcherMultiMap;
94
95  // Adds the list of URL filters in |matcher| to the URL matcher, having
96  // matches for those URLs map to |id|.
97  bool CreateConditionSets(
98      MatcherID id,
99      EventMatcher* matcher,
100      url_matcher::URLMatcherConditionSet::Vector* condition_sets);
101
102  bool AddDictionaryAsConditionSet(
103      base::DictionaryValue* url_filter,
104      url_matcher::URLMatcherConditionSet::Vector* condition_sets);
105
106  url_matcher::URLMatcher url_matcher_;
107  EventMatcherMultiMap event_matchers_;
108
109  // The next id to assign to an EventMatcher.
110  MatcherID next_id_;
111
112  // The next id to assign to a condition set passed to URLMatcher.
113  url_matcher::URLMatcherConditionSet::ID next_condition_set_id_;
114
115  // Maps condition set ids, which URLMatcher operates in, to event matcher
116  // ids, which the interface to this class operates in. As each EventFilter
117  // can specify many condition sets this is a many to one relationship.
118  std::map<url_matcher::URLMatcherConditionSet::ID, MatcherID>
119      condition_set_id_to_event_matcher_id_;
120
121  // Maps from event matcher ids to the name of the event they match on.
122  std::map<MatcherID, std::string> id_to_event_name_;
123
124  DISALLOW_COPY_AND_ASSIGN(EventFilter);
125};
126
127}  // namespace extensions
128
129#endif  // EXTENSIONS_COMMON_EVENT_FILTER_H_
130