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