Add common code for extensions event filtering.

chrome/common/extensions/filtered_event_router.h

Index: chrome/common/extensions/filtered_event_router.h
diff --git a/chrome/common/extensions/filtered_event_router.h b/chrome/common/extensions/filtered_event_router.h
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+++ b/chrome/common/extensions/filtered_event_router.h
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+// 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 CHROME_COMMON_EXTENSIONS_FILTERED_EVENT_ROUTER_H_
+#define CHROME_COMMON_EXTENSIONS_FILTERED_EVENT_ROUTER_H_
+#pragma once
+
+#include "base/memory/linked_ptr.h"
+#include "chrome/common/extensions/event_matcher.h"
+#include "chrome/common/extensions/event_filtering_info.h"
+#include "chrome/common/extensions/matcher/url_matcher.h"
+
+#include <map>
+#include <set>
+
+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 FilteredEventRouter {
+ public:
+  typedef int MatcherID;
+  FilteredEventRouter();
+  ~FilteredEventRouter();
+
+  // 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);

[battre, 2012/05/16 13:35:12]

As the event filters will come from extension code, it will be useful to pass an
error message here. Does not need to go into this CL.

[koz (OOO until 15th September), 2012/05/17 05:08:42]

Cool, I've added a TODO.

+  // 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.
+  std::set<MatcherID> MatchEvent(const std::string& event_name,
+                                 const EventFilteringInfo& event_info);
+
+  int GetMatcherCountForEvent(const std::string& event_name);
+
+ private:
+  typedef std::map<MatcherID, linked_ptr<EventMatcher> > EventMatcherMap;
+  typedef std::map<std::string, EventMatcherMap> EventMatcherMultiMap;

[battre, 2012/05/16 13:35:12]

optional:
typedef std::string EventName;
typedef std::map<EventName, EventMatcherMap> EventMatcherMultiMap;

alternatively: add comment?

[koz (OOO until 15th September), 2012/05/17 05:08:42]

I added comments here.

+
+  // Adds the list of filters to the URL matcher, having matches for those URLs
+  // map to |id|.
+  bool AddURLConditionsToURLMatcher(MatcherID id, base::ListValue* url_filters);
+
+  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(FilteredEventRouter);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_COMMON_EXTENSIONS_FILTERED_EVENT_ROUTER_H_