Add common code for extensions event filtering.

chrome/common/extensions/event_filter.cc

+// 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.
+
+#include "chrome/common/extensions/event_filter.h"
+
+#include "chrome/common/extensions/matcher/url_matcher_factory.h"
+
+namespace extensions {
+
+EventFilter::EventMatcherEntry::EventMatcherEntry(
+    scoped_ptr<EventMatcher> event_matcher,
+    URLMatcher* url_matcher,
+    const URLMatcherConditionSet::Vector& condition_sets)
+    : event_matcher_(event_matcher.Pass()),
+      url_matcher_(url_matcher) {
+  for (URLMatcherConditionSet::Vector::const_iterator it =
+       condition_sets.begin(); it != condition_sets.end(); it++)
+    condition_set_ids_.push_back((*it)->id());
+  url_matcher_->AddConditionSets(condition_sets);
+}
+
+EventFilter::EventMatcherEntry::~EventMatcherEntry() {
+  url_matcher_->RemoveConditionSets(condition_set_ids_);
+}
+
+void EventFilter::EventMatcherEntry::DontRemoveConditionSetsInDestructor() {
+  condition_set_ids_.clear();
+}
+
+EventFilter::EventFilter()
+    : next_id_(0),
+      next_condition_set_id_(0) {
+}
+
+EventFilter::~EventFilter() {
+  // Normally when an event matcher entry is removed from event_matchers_ it
+  // will remove its condition sets from url_matcher_, but as url_matcher_ is
+  // being destroyed anyway there is no need to do that step here.
+  for (EventMatcherMultiMap::iterator it = event_matchers_.begin();
+       it != event_matchers_.end(); it++) {
+    for (EventMatcherMap::iterator it2 = it->second.begin();
+         it2 != it->second.end(); it2++) {
+      it2->second->DontRemoveConditionSetsInDestructor();
+    }
+  }
+}
+
+EventFilter::MatcherID
+EventFilter::AddEventMatcher(const std::string& event_name,
+                             scoped_ptr<EventMatcher> matcher) {
+  MatcherID id = next_id_++;
+  URLMatcherConditionSet::Vector condition_sets;
+  if (!CreateConditionSets(id, matcher->url_filters(), &condition_sets))
+    return -1;
+
+  for (URLMatcherConditionSet::Vector::iterator it = condition_sets.begin();
+       it != condition_sets.end(); it++) {
+    condition_set_id_to_event_matcher_id_.insert(
+        std::make_pair((*it)->id(), id));
+  }
+  id_to_event_name_[id] = event_name;
+  event_matchers_[event_name][id] = linked_ptr<EventMatcherEntry>(
+      new EventMatcherEntry(matcher.Pass(), &url_matcher_, condition_sets));
+  return id;
+}
+
+bool EventFilter::CreateConditionSets(
+    MatcherID id,
+    base::ListValue* url_filters,
+    URLMatcherConditionSet::Vector* condition_sets) {
+  if (!url_filters || url_filters->GetSize() == 0) {
+    // If there are no url_filters then we want to match all events, so create a
+    // URLFilter from an empty dictionary.
+    base::DictionaryValue empty_dict;
+    return AddDictionaryAsConditionSet(&empty_dict, condition_sets);
+  }
+  for (size_t i = 0; i < url_filters->GetSize(); i++) {
+    base::DictionaryValue* url_filter;
+    if (!url_filters->GetDictionary(i, &url_filter))
+      return false;
+    if (!AddDictionaryAsConditionSet(url_filter, condition_sets))
+      return false;
+  }
+  return true;
+}
+
+bool EventFilter::AddDictionaryAsConditionSet(
+    base::DictionaryValue* url_filter,
+    URLMatcherConditionSet::Vector* condition_sets) {
+  std::string error;
+  URLMatcherConditionSet::ID condition_set_id = next_condition_set_id_++;
+  condition_sets->push_back(URLMatcherFactory::CreateFromURLFilterDictionary(
+      url_matcher_.condition_factory(),
+      url_filter,
+      condition_set_id,
+      &error));
+  if (!error.empty()) {
+    LOG(ERROR) << "CreateFromURLFilterDictionary failed: " << error;
+    url_matcher_.ClearUnusedConditionSets();
+    condition_sets->clear();
+    return false;
+  }
+  return true;
+}
+
+std::string EventFilter::RemoveEventMatcher(MatcherID id) {
+  std::map<MatcherID, std::string>::iterator it = id_to_event_name_.find(id);
+  event_matchers_[it->second].erase(id);
+  std::string event_name = it->second;
+  id_to_event_name_.erase(it);
+  return event_name;
+}
+
+std::set<EventFilter::MatcherID> EventFilter::MatchEvent(
+    const std::string& event_name, const EventFilteringInfo& event_info) {
+  std::set<MatcherID> matchers;
+  EventMatcherMultiMap::iterator it = event_matchers_.find(event_name);
+  if (it == event_matchers_.end())
+    return matchers;
+
+  EventMatcherMap& matcher_map = it->second;
+  GURL url_to_match_against = event_info.has_url() ? event_info.url() : GURL();
+  std::set<URLMatcherConditionSet::ID> matching_condition_set_ids =
+      url_matcher_.MatchURL(url_to_match_against);
+  for (std::set<URLMatcherConditionSet::ID>::iterator it =
+       matching_condition_set_ids.begin();
+       it != matching_condition_set_ids.end(); it++) {
+    MatcherID id = condition_set_id_to_event_matcher_id_[*it];
+    const EventMatcher& event_matcher = matcher_map[id]->event_matcher();
+    if (event_matcher.MatchNonURLCriteria(event_info)) {
+      CHECK(!event_matcher.url_filters() || event_info.has_url());
+      matchers.insert(id);
+    }
+  }
+
+  return matchers;
+}
+
+int EventFilter::GetMatcherCountForEvent(const std::string& name) {
+  EventMatcherMultiMap::const_iterator it = event_matchers_.find(name);
+  if (it == event_matchers_.end())
+    return 0;
+
+  return it->second.size();
+}
+
+}  // namespace extensions