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      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 #include "extensions/common/event_filter.h"
      6 
      7 #include "components/url_matcher/url_matcher_factory.h"
      8 #include "ipc/ipc_message.h"
      9 
     10 using url_matcher::URLMatcher;
     11 using url_matcher::URLMatcherConditionSet;
     12 using url_matcher::URLMatcherFactory;
     13 
     14 namespace extensions {
     15 
     16 EventFilter::EventMatcherEntry::EventMatcherEntry(
     17     scoped_ptr<EventMatcher> event_matcher,
     18     URLMatcher* url_matcher,
     19     const URLMatcherConditionSet::Vector& condition_sets)
     20     : event_matcher_(event_matcher.Pass()),
     21       url_matcher_(url_matcher) {
     22   for (URLMatcherConditionSet::Vector::const_iterator it =
     23        condition_sets.begin(); it != condition_sets.end(); it++)
     24     condition_set_ids_.push_back((*it)->id());
     25   url_matcher_->AddConditionSets(condition_sets);
     26 }
     27 
     28 EventFilter::EventMatcherEntry::~EventMatcherEntry() {
     29   url_matcher_->RemoveConditionSets(condition_set_ids_);
     30 }
     31 
     32 void EventFilter::EventMatcherEntry::DontRemoveConditionSetsInDestructor() {
     33   condition_set_ids_.clear();
     34 }
     35 
     36 EventFilter::EventFilter()
     37     : next_id_(0),
     38       next_condition_set_id_(0) {
     39 }
     40 
     41 EventFilter::~EventFilter() {
     42   // Normally when an event matcher entry is removed from event_matchers_ it
     43   // will remove its condition sets from url_matcher_, but as url_matcher_ is
     44   // being destroyed anyway there is no need to do that step here.
     45   for (EventMatcherMultiMap::iterator it = event_matchers_.begin();
     46        it != event_matchers_.end(); it++) {
     47     for (EventMatcherMap::iterator it2 = it->second.begin();
     48          it2 != it->second.end(); it2++) {
     49       it2->second->DontRemoveConditionSetsInDestructor();
     50     }
     51   }
     52 }
     53 
     54 EventFilter::MatcherID
     55 EventFilter::AddEventMatcher(const std::string& event_name,
     56                              scoped_ptr<EventMatcher> matcher) {
     57   MatcherID id = next_id_++;
     58   URLMatcherConditionSet::Vector condition_sets;
     59   if (!CreateConditionSets(id, matcher.get(), &condition_sets))
     60     return -1;
     61 
     62   for (URLMatcherConditionSet::Vector::iterator it = condition_sets.begin();
     63        it != condition_sets.end(); it++) {
     64     condition_set_id_to_event_matcher_id_.insert(
     65         std::make_pair((*it)->id(), id));
     66   }
     67   id_to_event_name_[id] = event_name;
     68   event_matchers_[event_name][id] = linked_ptr<EventMatcherEntry>(
     69       new EventMatcherEntry(matcher.Pass(), &url_matcher_, condition_sets));
     70   return id;
     71 }
     72 
     73 EventMatcher* EventFilter::GetEventMatcher(MatcherID id) {
     74   DCHECK(id_to_event_name_.find(id) != id_to_event_name_.end());
     75   const std::string& event_name = id_to_event_name_[id];
     76   return event_matchers_[event_name][id]->event_matcher();
     77 }
     78 
     79 const std::string& EventFilter::GetEventName(MatcherID id) {
     80   DCHECK(id_to_event_name_.find(id) != id_to_event_name_.end());
     81   return id_to_event_name_[id];
     82 }
     83 
     84 bool EventFilter::CreateConditionSets(
     85     MatcherID id,
     86     EventMatcher* matcher,
     87     URLMatcherConditionSet::Vector* condition_sets) {
     88   if (matcher->GetURLFilterCount() == 0) {
     89     // If there are no URL filters then we want to match all events, so create a
     90     // URLFilter from an empty dictionary.
     91     base::DictionaryValue empty_dict;
     92     return AddDictionaryAsConditionSet(&empty_dict, condition_sets);
     93   }
     94   for (int i = 0; i < matcher->GetURLFilterCount(); i++) {
     95     base::DictionaryValue* url_filter;
     96     if (!matcher->GetURLFilter(i, &url_filter))
     97       return false;
     98     if (!AddDictionaryAsConditionSet(url_filter, condition_sets))
     99       return false;
    100   }
    101   return true;
    102 }
    103 
    104 bool EventFilter::AddDictionaryAsConditionSet(
    105     base::DictionaryValue* url_filter,
    106     URLMatcherConditionSet::Vector* condition_sets) {
    107   std::string error;
    108   URLMatcherConditionSet::ID condition_set_id = next_condition_set_id_++;
    109   condition_sets->push_back(URLMatcherFactory::CreateFromURLFilterDictionary(
    110       url_matcher_.condition_factory(),
    111       url_filter,
    112       condition_set_id,
    113       &error));
    114   if (!error.empty()) {
    115     LOG(ERROR) << "CreateFromURLFilterDictionary failed: " << error;
    116     url_matcher_.ClearUnusedConditionSets();
    117     condition_sets->clear();
    118     return false;
    119   }
    120   return true;
    121 }
    122 
    123 std::string EventFilter::RemoveEventMatcher(MatcherID id) {
    124   std::map<MatcherID, std::string>::iterator it = id_to_event_name_.find(id);
    125   std::string event_name = it->second;
    126   // EventMatcherEntry's destructor causes the condition set ids to be removed
    127   // from url_matcher_.
    128   event_matchers_[event_name].erase(id);
    129   id_to_event_name_.erase(it);
    130   return event_name;
    131 }
    132 
    133 std::set<EventFilter::MatcherID> EventFilter::MatchEvent(
    134     const std::string& event_name, const EventFilteringInfo& event_info,
    135     int routing_id) {
    136   std::set<MatcherID> matchers;
    137 
    138   EventMatcherMultiMap::iterator it = event_matchers_.find(event_name);
    139   if (it == event_matchers_.end())
    140     return matchers;
    141 
    142   EventMatcherMap& matcher_map = it->second;
    143   GURL url_to_match_against = event_info.has_url() ? event_info.url() : GURL();
    144   std::set<URLMatcherConditionSet::ID> matching_condition_set_ids =
    145       url_matcher_.MatchURL(url_to_match_against);
    146   for (std::set<URLMatcherConditionSet::ID>::iterator it =
    147        matching_condition_set_ids.begin();
    148        it != matching_condition_set_ids.end(); it++) {
    149     std::map<URLMatcherConditionSet::ID, MatcherID>::iterator matcher_id =
    150         condition_set_id_to_event_matcher_id_.find(*it);
    151     if (matcher_id == condition_set_id_to_event_matcher_id_.end()) {
    152       NOTREACHED() << "id not found in condition set map (" << (*it) << ")";
    153       continue;
    154     }
    155     MatcherID id = matcher_id->second;
    156     EventMatcherMap::iterator matcher_entry = matcher_map.find(id);
    157     if (matcher_entry == matcher_map.end()) {
    158       // Matcher must be for a different event.
    159       continue;
    160     }
    161     const EventMatcher* event_matcher = matcher_entry->second->event_matcher();
    162     // The context that installed the event listener should be the same context
    163     // as the one where the event listener is called.
    164     if ((routing_id != MSG_ROUTING_NONE) &&
    165         (event_matcher->GetRoutingID() != routing_id)) {
    166       continue;
    167     }
    168     if (event_matcher->MatchNonURLCriteria(event_info)) {
    169       CHECK(!event_matcher->HasURLFilters() || event_info.has_url());
    170       matchers.insert(id);
    171     }
    172   }
    173 
    174   return matchers;
    175 }
    176 
    177 int EventFilter::GetMatcherCountForEvent(const std::string& name) {
    178   EventMatcherMultiMap::const_iterator it = event_matchers_.find(name);
    179   if (it == event_matchers_.end())
    180     return 0;
    181 
    182   return it->second.size();
    183 }
    184 
    185 }  // namespace extensions
    186