Move EventFilter, EventFilteringInfo and EventMatcher

classes to extensions/common/

TBR=ben@chromium.org
BUG=162530

Review URL: https://chromiumcodereview.appspot.com/12208078

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@181849 0039d316-1c4b-4281-b951-d872f2087c98

7 files changed, 734 insertions, 0 deletions

diff --git a/extensions/common/event_filter.cc b/extensions/common/event_filter.cc
new file mode 100644
index 0000000..e5d6b1d
--- /dev/null
+++ b/extensions/common/event_filter.cc
@@ -0,0 +1,172 @@
+// 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 "extensions/common/event_filter.h"
+
+#include "extensions/common/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.get(), &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;
+}
+
+EventMatcher* EventFilter::GetEventMatcher(MatcherID id) {
+  DCHECK(id_to_event_name_.find(id) != id_to_event_name_.end());
+  const std::string& event_name = id_to_event_name_[id];
+  return event_matchers_[event_name][id]->event_matcher();
+}
+
+const std::string& EventFilter::GetEventName(MatcherID id) {
+  DCHECK(id_to_event_name_.find(id) != id_to_event_name_.end());
+  return id_to_event_name_[id];
+}
+
+bool EventFilter::CreateConditionSets(
+    MatcherID id,
+    EventMatcher* matcher,
+    URLMatcherConditionSet::Vector* condition_sets) {
+  if (matcher->GetURLFilterCount() == 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 (int i = 0; i < matcher->GetURLFilterCount(); i++) {
+    base::DictionaryValue* url_filter;
+    if (!matcher->GetURLFilter(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);
+  std::string event_name = it->second;
+  // EventMatcherEntry's destructor causes the condition set ids to be removed
+  // from url_matcher_.
+  event_matchers_[event_name].erase(id);
+  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++) {
+    std::map<URLMatcherConditionSet::ID, MatcherID>::iterator matcher_id =
+        condition_set_id_to_event_matcher_id_.find(*it);
+    if (matcher_id == condition_set_id_to_event_matcher_id_.end()) {
+      NOTREACHED() << "id not found in condition set map (" << (*it) << ")";
+      continue;
+    }
+    MatcherID id = matcher_id->second;
+    EventMatcherMap::iterator matcher_entry = matcher_map.find(id);
+    if (matcher_entry == matcher_map.end()) {
+      // Matcher must be for a different event.
+      continue;
+    }
+    const EventMatcher* event_matcher = matcher_entry->second->event_matcher();
+    if (event_matcher->MatchNonURLCriteria(event_info)) {
+      CHECK(!event_matcher->HasURLFilters() || 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
diff --git a/extensions/common/event_filter.h b/extensions/common/event_filter.h
new file mode 100644
index 0000000..efde6035
--- /dev/null
+++ b/extensions/common/event_filter.h
@@ -0,0 +1,126 @@
+// 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.
+
+#ifndef EXTENSIONS_COMMON_EVENT_FILTER_H_
+#define EXTENSIONS_COMMON_EVENT_FILTER_H_
+
+#include <map>
+#include <set>
+
+#include "base/memory/linked_ptr.h"
+#include "extensions/common/event_filtering_info.h"
+#include "extensions/common/event_matcher.h"
+#include "extensions/common/matcher/url_matcher.h"
+
+namespace extensions {
+
+// Matches incoming events against a collection of EventMatchers. Each added
+// EventMatcher is given an id which is returned by MatchEvent() when it is
+// passed a matching event.
+class EventFilter {
+ public:
+  typedef int MatcherID;
+  EventFilter();
+  ~EventFilter();
+
+  // Adds an event matcher that will be used in calls to MatchEvent(). Returns
+  // the id of the matcher, or -1 if there was an error.
+  MatcherID AddEventMatcher(const std::string& event_name,
+                            scoped_ptr<EventMatcher> matcher);
+
+  // Retrieve the EventMatcher with the given id.
+  EventMatcher* GetEventMatcher(MatcherID id);
+
+  // Retrieve the name of the event that the EventMatcher specified by |id| is
+  // referring to.
+  const std::string& GetEventName(MatcherID id);
+
+  // Removes an event matcher, returning the name of the event that it was for.
+  std::string RemoveEventMatcher(MatcherID id);
+
+  // Match an event named |event_name| with filtering info |event_info| against
+  // our set of event matchers. Returns a set of ids that correspond to the
+  // event matchers that matched the event.
+  // TODO(koz): Add a std::string* parameter for retrieving error messages.
+  std::set<MatcherID> MatchEvent(const std::string& event_name,
+                                 const EventFilteringInfo& event_info);
+
+  int GetMatcherCountForEvent(const std::string& event_name);
+
+  // For testing.
+  bool IsURLMatcherEmpty() const {
+    return url_matcher_.IsEmpty();
+  }
+
+ private:
+  class EventMatcherEntry {
+   public:
+    // Adds |condition_sets| to |url_matcher| on construction and removes them
+    // again on destruction. |condition_sets| should be the
+    // URLMatcherConditionSets that match the URL constraints specified by
+    // |event_matcher|.
+    EventMatcherEntry(scoped_ptr<EventMatcher> event_matcher,
+                      URLMatcher* url_matcher,
+                      const URLMatcherConditionSet::Vector& condition_sets);
+    ~EventMatcherEntry();
+
+    // Prevents the removal of condition sets when this class is destroyed. We
+    // call this in EventFilter's destructor so that we don't do the costly
+    // removal of condition sets when the URLMatcher is going to be destroyed
+    // and clean them up anyway.
+    void DontRemoveConditionSetsInDestructor();
+
+    EventMatcher* event_matcher() {
+      return event_matcher_.get();
+    }
+
+   private:
+    scoped_ptr<EventMatcher> event_matcher_;
+    // The id sets in url_matcher_ that this EventMatcher owns.
+    std::vector<URLMatcherConditionSet::ID> condition_set_ids_;
+    URLMatcher* url_matcher_;
+
+    DISALLOW_COPY_AND_ASSIGN(EventMatcherEntry);
+  };
+
+  // Maps from a matcher id to an event matcher entry.
+  typedef std::map<MatcherID, linked_ptr<EventMatcherEntry> > EventMatcherMap;
+
+  // Maps from event name to the map of matchers that are registered for it.
+  typedef std::map<std::string, EventMatcherMap> EventMatcherMultiMap;
+
+  // Adds the list of URL filters in |matcher| to the URL matcher, having
+  // matches for those URLs map to |id|.
+  bool CreateConditionSets(MatcherID id,
+                           EventMatcher* matcher,
+                           URLMatcherConditionSet::Vector* condition_sets);
+
+  bool AddDictionaryAsConditionSet(
+      base::DictionaryValue* url_filter,
+      URLMatcherConditionSet::Vector* condition_sets);
+
+  URLMatcher url_matcher_;
+  EventMatcherMultiMap event_matchers_;
+
+  // The next id to assign to an EventMatcher.
+  MatcherID next_id_;
+
+  // The next id to assign to a condition set passed to URLMatcher.
+  URLMatcherConditionSet::ID next_condition_set_id_;
+
+  // Maps condition set ids, which URLMatcher operates in, to event matcher
+  // ids, which the interface to this class operates in. As each EventFilter
+  // can specify many condition sets this is a many to one relationship.
+  std::map<URLMatcherConditionSet::ID, MatcherID>
+      condition_set_id_to_event_matcher_id_;
+
+  // Maps from event matcher ids to the name of the event they match on.
+  std::map<MatcherID, std::string> id_to_event_name_;
+
+  DISALLOW_COPY_AND_ASSIGN(EventFilter);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_COMMON_EVENT_FILTER_H_
diff --git a/extensions/common/event_filter_unittest.cc b/extensions/common/event_filter_unittest.cc
new file mode 100644
index 0000000..9b7f4ba
--- /dev/null
+++ b/extensions/common/event_filter_unittest.cc
@@ -0,0 +1,244 @@
+// 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 "base/memory/scoped_ptr.h"
+#include "base/values.h"
+#include "extensions/common/event_filter.h"
+#include "extensions/common/event_filtering_info.h"
+#include "extensions/common/event_matcher.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace extensions {
+
+class EventFilterUnittest : public testing::Test {
+ public:
+  EventFilterUnittest() {
+    google_event_.SetURL(GURL("http://google.com"));
+    yahoo_event_.SetURL(GURL("http://yahoo.com"));
+    random_url_event_.SetURL(GURL("http://www.something-else.com"));
+    empty_url_event_.SetURL(GURL());
+  }
+
+ protected:
+  scoped_ptr<base::Value> HostSuffixDict(const std::string& host_suffix) {
+    scoped_ptr<base::DictionaryValue> dict(new DictionaryValue());
+    dict->Set("hostSuffix", base::Value::CreateStringValue(host_suffix));
+    return scoped_ptr<base::Value>(dict.release());
+  }
+
+  scoped_ptr<base::ListValue> ValueAsList(scoped_ptr<base::Value> value) {
+    scoped_ptr<base::ListValue> result(new base::ListValue());
+    result->Append(value.release());
+    return result.Pass();
+  }
+
+  scoped_ptr<EventMatcher> AllURLs() {
+    return scoped_ptr<EventMatcher>(new EventMatcher(
+        scoped_ptr<DictionaryValue>(new DictionaryValue)));
+  }
+
+  scoped_ptr<EventMatcher> HostSuffixMatcher(const std::string& host_suffix) {
+    return MatcherFromURLFilterList(ValueAsList(HostSuffixDict(host_suffix)));
+  }
+
+  scoped_ptr<EventMatcher> MatcherFromURLFilterList(
+      scoped_ptr<ListValue> url_filter_list) {
+    scoped_ptr<DictionaryValue> filter_dict(new DictionaryValue);
+    filter_dict->Set("url", url_filter_list.release());
+    return scoped_ptr<EventMatcher>(new EventMatcher(filter_dict.Pass()));
+  }
+
+  EventFilter event_filter_;
+  EventFilteringInfo empty_event_;
+  EventFilteringInfo google_event_;
+  EventFilteringInfo yahoo_event_;
+  EventFilteringInfo random_url_event_;
+  EventFilteringInfo empty_url_event_;
+};
+
+TEST_F(EventFilterUnittest, NoMatchersMatchIfEmpty) {
+  std::set<int> matches = event_filter_.MatchEvent("some-event",
+                                                   empty_event_);
+  ASSERT_EQ(0u, matches.size());
+}
+
+TEST_F(EventFilterUnittest, AddingEventMatcherDoesntCrash) {
+  event_filter_.AddEventMatcher("event1", AllURLs());
+}
+
+TEST_F(EventFilterUnittest,
+    DontMatchAgainstMatchersForDifferentEvents) {
+  event_filter_.AddEventMatcher("event1", AllURLs());
+  std::set<int> matches = event_filter_.MatchEvent("event2",
+                                                   empty_event_);
+  ASSERT_EQ(0u, matches.size());
+}
+
+TEST_F(EventFilterUnittest, DoMatchAgainstMatchersForSameEvent) {
+  int id = event_filter_.AddEventMatcher("event1", AllURLs());
+  std::set<int> matches = event_filter_.MatchEvent("event1",
+      google_event_);
+  ASSERT_EQ(1u, matches.size());
+  ASSERT_EQ(1u, matches.count(id));
+}
+
+TEST_F(EventFilterUnittest, DontMatchUnlessMatcherMatches) {
+  EventFilteringInfo info;
+  info.SetURL(GURL("http://www.yahoo.com"));
+  event_filter_.AddEventMatcher("event1", HostSuffixMatcher("google.com"));
+  std::set<int> matches = event_filter_.MatchEvent("event1", info);
+  ASSERT_TRUE(matches.empty());
+}
+
+TEST_F(EventFilterUnittest, RemovingAnEventMatcherStopsItMatching) {
+  int id = event_filter_.AddEventMatcher("event1", AllURLs());
+  event_filter_.RemoveEventMatcher(id);
+  std::set<int> matches = event_filter_.MatchEvent("event1",
+                                                   empty_event_);
+  ASSERT_TRUE(matches.empty());
+}
+
+TEST_F(EventFilterUnittest, MultipleEventMatches) {
+  int id1 = event_filter_.AddEventMatcher("event1", AllURLs());
+  int id2 = event_filter_.AddEventMatcher("event1", AllURLs());
+  std::set<int> matches = event_filter_.MatchEvent("event1",
+      google_event_);
+  ASSERT_EQ(2u, matches.size());
+  ASSERT_EQ(1u, matches.count(id1));
+  ASSERT_EQ(1u, matches.count(id2));
+}
+
+TEST_F(EventFilterUnittest, TestURLMatching) {
+  EventFilteringInfo info;
+  info.SetURL(GURL("http://www.google.com"));
+  int id = event_filter_.AddEventMatcher("event1",
+                                         HostSuffixMatcher("google.com"));
+  std::set<int> matches = event_filter_.MatchEvent("event1", info);
+  ASSERT_EQ(1u, matches.size());
+  ASSERT_EQ(1u, matches.count(id));
+}
+
+TEST_F(EventFilterUnittest, TestMultipleURLFiltersMatchOnAny) {
+  scoped_ptr<base::ListValue> filters(new base::ListValue());
+  filters->Append(HostSuffixDict("google.com").release());
+  filters->Append(HostSuffixDict("yahoo.com").release());
+
+  scoped_ptr<EventMatcher> matcher(MatcherFromURLFilterList(filters.Pass()));
+  int id = event_filter_.AddEventMatcher("event1", matcher.Pass());
+
+  {
+    std::set<int> matches = event_filter_.MatchEvent("event1",
+        google_event_);
+    ASSERT_EQ(1u, matches.size());
+    ASSERT_EQ(1u, matches.count(id));
+  }
+  {
+    std::set<int> matches = event_filter_.MatchEvent("event1",
+        yahoo_event_);
+    ASSERT_EQ(1u, matches.size());
+    ASSERT_EQ(1u, matches.count(id));
+  }
+  {
+    std::set<int> matches = event_filter_.MatchEvent("event1",
+        random_url_event_);
+    ASSERT_EQ(0u, matches.size());
+  }
+}
+
+TEST_F(EventFilterUnittest, TestStillMatchesAfterRemoval) {
+  int id1 = event_filter_.AddEventMatcher("event1", AllURLs());
+  int id2 = event_filter_.AddEventMatcher("event1", AllURLs());
+
+  event_filter_.RemoveEventMatcher(id1);
+  {
+    std::set<int> matches = event_filter_.MatchEvent("event1",
+        google_event_);
+    ASSERT_EQ(1u, matches.size());
+    ASSERT_EQ(1u, matches.count(id2));
+  }
+}
+
+TEST_F(EventFilterUnittest, TestMatchesOnlyAgainstPatternsForCorrectEvent) {
+  int id1 = event_filter_.AddEventMatcher("event1", AllURLs());
+  event_filter_.AddEventMatcher("event2", AllURLs());
+
+  {
+    std::set<int> matches = event_filter_.MatchEvent("event1",
+        google_event_);
+    ASSERT_EQ(1u, matches.size());
+    ASSERT_EQ(1u, matches.count(id1));
+  }
+}
+
+TEST_F(EventFilterUnittest, TestGetMatcherCountForEvent) {
+  ASSERT_EQ(0, event_filter_.GetMatcherCountForEvent("event1"));
+  int id1 = event_filter_.AddEventMatcher("event1", AllURLs());
+  ASSERT_EQ(1, event_filter_.GetMatcherCountForEvent("event1"));
+  int id2 = event_filter_.AddEventMatcher("event1", AllURLs());
+  ASSERT_EQ(2, event_filter_.GetMatcherCountForEvent("event1"));
+  event_filter_.RemoveEventMatcher(id1);
+  ASSERT_EQ(1, event_filter_.GetMatcherCountForEvent("event1"));
+  event_filter_.RemoveEventMatcher(id2);
+  ASSERT_EQ(0, event_filter_.GetMatcherCountForEvent("event1"));
+}
+
+TEST_F(EventFilterUnittest, RemoveEventMatcherReturnsEventName) {
+  int id1 = event_filter_.AddEventMatcher("event1", AllURLs());
+  int id2 = event_filter_.AddEventMatcher("event1", AllURLs());
+  int id3 = event_filter_.AddEventMatcher("event2", AllURLs());
+
+  ASSERT_EQ("event1", event_filter_.RemoveEventMatcher(id1));
+  ASSERT_EQ("event1", event_filter_.RemoveEventMatcher(id2));
+  ASSERT_EQ("event2", event_filter_.RemoveEventMatcher(id3));
+}
+
+TEST_F(EventFilterUnittest, InvalidURLFilterCantBeAdded) {
+  scoped_ptr<base::ListValue> filter_list(new base::ListValue());
+  filter_list->Append(new base::ListValue());  // Should be a dict.
+  scoped_ptr<EventMatcher> matcher(MatcherFromURLFilterList(
+      filter_list.Pass()));
+  int id1 = event_filter_.AddEventMatcher("event1", matcher.Pass());
+  EXPECT_TRUE(event_filter_.IsURLMatcherEmpty());
+  ASSERT_EQ(-1, id1);
+}
+
+TEST_F(EventFilterUnittest, EmptyListOfURLFiltersMatchesAllURLs) {
+  scoped_ptr<base::ListValue> filter_list(new base::ListValue());
+  scoped_ptr<EventMatcher> matcher(MatcherFromURLFilterList(
+      scoped_ptr<ListValue>(new ListValue)));
+  int id = event_filter_.AddEventMatcher("event1", matcher.Pass());
+  std::set<int> matches = event_filter_.MatchEvent("event1",
+      google_event_);
+  ASSERT_EQ(1u, matches.size());
+  ASSERT_EQ(1u, matches.count(id));
+}
+
+TEST_F(EventFilterUnittest,
+    InternalURLMatcherShouldBeEmptyWhenThereAreNoEventMatchers) {
+  ASSERT_TRUE(event_filter_.IsURLMatcherEmpty());
+  int id = event_filter_.AddEventMatcher("event1",
+                                         HostSuffixMatcher("google.com"));
+  ASSERT_FALSE(event_filter_.IsURLMatcherEmpty());
+  event_filter_.RemoveEventMatcher(id);
+  ASSERT_TRUE(event_filter_.IsURLMatcherEmpty());
+}
+
+TEST_F(EventFilterUnittest, EmptyURLsShouldBeMatchedByEmptyURLFilters) {
+  int id = event_filter_.AddEventMatcher("event1", AllURLs());
+  std::set<int> matches = event_filter_.MatchEvent("event1", empty_url_event_);
+  ASSERT_EQ(1u, matches.size());
+  ASSERT_EQ(1u, matches.count(id));
+}
+
+TEST_F(EventFilterUnittest,
+    EmptyURLsShouldBeMatchedByEmptyURLFiltersWithAnEmptyItem) {
+  scoped_ptr<EventMatcher> matcher(MatcherFromURLFilterList(ValueAsList(
+      scoped_ptr<Value>(new DictionaryValue()))));
+  int id = event_filter_.AddEventMatcher("event1", matcher.Pass());
+  std::set<int> matches = event_filter_.MatchEvent("event1", empty_url_event_);
+  ASSERT_EQ(1u, matches.size());
+  ASSERT_EQ(1u, matches.count(id));
+}
+
+}  // namespace extensions
diff --git a/extensions/common/event_filtering_info.cc b/extensions/common/event_filtering_info.cc
new file mode 100644
index 0000000..009dcaa
--- /dev/null
+++ b/extensions/common/event_filtering_info.cc
@@ -0,0 +1,48 @@
+// 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 "extensions/common/event_filtering_info.h"
+
+#include "base/json/json_writer.h"
+#include "base/values.h"
+
+namespace extensions {
+
+EventFilteringInfo::EventFilteringInfo()
+    : has_url_(false) {
+}
+
+EventFilteringInfo::~EventFilteringInfo() {
+}
+
+void EventFilteringInfo::SetURL(const GURL& url) {
+  url_ = url;
+  has_url_ = true;
+}
+
+std::string EventFilteringInfo::AsJSONString() const {
+  std::string result;
+  base::DictionaryValue value;
+  if (has_url_)
+    value.SetString("url", url_.spec());
+
+  base::JSONWriter::Write(&value, &result);
+  return result;
+}
+
+scoped_ptr<base::Value> EventFilteringInfo::AsValue() const {
+  if (IsEmpty())
+    return scoped_ptr<base::Value>(base::Value::CreateNullValue());
+
+  scoped_ptr<base::DictionaryValue> result(new base::DictionaryValue);
+  if (has_url_)
+    result->SetString("url", url_.spec());
+  return result.PassAs<base::Value>();
+}
+
+bool EventFilteringInfo::IsEmpty() const {
+  return !has_url_;
+}
+
+}  // namespace extensions
diff --git a/extensions/common/event_filtering_info.h b/extensions/common/event_filtering_info.h
new file mode 100644
index 0000000..2fee9c1
--- /dev/null
+++ b/extensions/common/event_filtering_info.h
@@ -0,0 +1,47 @@
+// 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.
+
+#ifndef EXTENSIONS_COMMON_EVENT_FILTERING_INFO_H_
+#define EXTENSIONS_COMMON_EVENT_FILTERING_INFO_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "googleurl/src/gurl.h"
+
+namespace base {
+class Value;
+}
+
+namespace extensions {
+
+// Extra information about an event that is used in event filtering.
+//
+// This is the information that is matched against criteria specified in JS
+// extension event listeners. Eg:
+//
+// chrome.someApi.onSomeEvent.addListener(cb,
+//                                        {url: [{hostSuffix: 'google.com'}],
+//                                         tabId: 1});
+class EventFilteringInfo {
+ public:
+  EventFilteringInfo();
+  ~EventFilteringInfo();
+  void SetURL(const GURL& url);
+
+  bool has_url() const { return has_url_; }
+  const GURL& url() const { return url_; }
+
+  std::string AsJSONString() const;
+  scoped_ptr<base::Value> AsValue() const;
+  bool IsEmpty() const;
+
+ private:
+  bool has_url_;
+  GURL url_;
+
+  // Allow implicit copy and assignment.
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_COMMON_EVENT_FILTERING_INFO_H_
diff --git a/extensions/common/event_matcher.cc b/extensions/common/event_matcher.cc
new file mode 100644
index 0000000..c982937
--- /dev/null
+++ b/extensions/common/event_matcher.cc
@@ -0,0 +1,47 @@
+// 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 "extensions/common/event_matcher.h"
+
+#include "extensions/common/event_filtering_info.h"
+
+namespace {
+const char kUrlFiltersKey[] = "url";
+}
+
+namespace extensions {
+
+EventMatcher::EventMatcher(scoped_ptr<base::DictionaryValue> filter)
+    : filter_(filter.Pass()) {
+}
+
+EventMatcher::~EventMatcher() {
+}
+
+bool EventMatcher::MatchNonURLCriteria(
+    const EventFilteringInfo& event_info) const {
+  // There is currently no criteria apart from URL criteria.
+  return true;
+}
+
+int EventMatcher::GetURLFilterCount() const {
+  base::ListValue* url_filters = NULL;
+  if (filter_->GetList(kUrlFiltersKey, &url_filters))
+    return url_filters->GetSize();
+  return 0;
+}
+
+bool EventMatcher::GetURLFilter(int i, base::DictionaryValue** url_filter_out) {
+  base::ListValue* url_filters = NULL;
+  if (filter_->GetList(kUrlFiltersKey, &url_filters)) {
+    return url_filters->GetDictionary(i, url_filter_out);
+  }
+  return false;
+}
+
+int EventMatcher::HasURLFilters() const {
+  return GetURLFilterCount() != 0;
+}
+
+}  // namespace extensions
diff --git a/extensions/common/event_matcher.h b/extensions/common/event_matcher.h
new file mode 100644
index 0000000..bb28419
--- /dev/null
+++ b/extensions/common/event_matcher.h
@@ -0,0 +1,50 @@
+// 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.
+
+#ifndef EXTENSIONS_COMMON_EVENT_MATCHER_H_
+#define EXTENSIONS_COMMON_EVENT_MATCHER_H_
+
+#include "base/memory/scoped_ptr.h"
+#include "base/values.h"
+
+namespace extensions {
+
+class EventFilteringInfo;
+
+// Matches EventFilteringInfos against a set of criteria. This is intended to
+// be used by EventFilter which performs efficient URL matching across
+// potentially many EventMatchers itself. This is why this class only exposes
+// MatchNonURLCriteria() - URL matching is handled by EventFilter.
+class EventMatcher {
+ public:
+  explicit EventMatcher(scoped_ptr<base::DictionaryValue> filter);
+  ~EventMatcher();
+
+  // Returns true if |event_info| satisfies this matcher's criteria, not taking
+  // into consideration any URL criteria.
+  bool MatchNonURLCriteria(const EventFilteringInfo& event_info) const;
+
+  int GetURLFilterCount() const;
+  bool GetURLFilter(int i, base::DictionaryValue** url_filter_out);
+
+  int HasURLFilters() const;
+
+  base::DictionaryValue* value() const {
+    return filter_.get();
+  }
+
+ private:
+  // Contains a dictionary that corresponds to a single event filter, eg:
+  //
+  // {url: [{hostSuffix: 'google.com'}]}
+  //
+  // The valid filter keys are event-specific.
+  scoped_ptr<base::DictionaryValue> filter_;
+
+  DISALLOW_COPY_AND_ASSIGN(EventMatcher);
+};
+
+}  // namespace extensions
+
+#endif  // EXTENSIONS_COMMON_EVENT_MATCHER_H_