extensions/common/event_filter.h

   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
  16 namespace 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.
  21 class 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_