Filtered events.

chrome/browser/extensions/event_listener_map.h

Index: chrome/browser/extensions/event_listener_map.h
diff --git a/chrome/browser/extensions/event_listener_map.h b/chrome/browser/extensions/event_listener_map.h
new file mode 100644
index 0000000000000000000000000000000000000000..a1a4763398ed77e36b7b3b3c484f3f5a8c571f5e
--- /dev/null
+++ b/chrome/browser/extensions/event_listener_map.h
@@ -0,0 +1,149 @@
+// 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_BROWSER_EXTENSIONS_EVENT_LISTENER_MAP_H_
+#define CHROME_BROWSER_EXTENSIONS_EVENT_LISTENER_MAP_H_
+#pragma once
+
+#include "base/memory/scoped_ptr.h"
+#include "chrome/common/extensions/event_filter.h"
+
+#include <map>
+#include <set>
+#include <string>
+#include <vector>
+
+namespace base {
+class DictionaryValue;
+}
+
+namespace content {
+class RenderProcessHost;
+}
+
+struct ExtensionEvent;
+class ListenerRemovalListener;
+
+using base::DictionaryValue;
+
+namespace extensions {
+
+// A listener for an extension event. A listener is essentially an endpoint
+// that an event can be dispatched to. This is a lazy listener if |process| is
+// NULL and a filtered listener if |filter| is defined.
+//
+// A lazy listener is added to an event to indicate that a lazy background page
+// is listening to the event. It is associated with no process, so to dispatch
+// an event to a lazy listener one must start a process running the associated
+// extension and dispatch the event to that.
+//
+struct EventListener {
+  // |filter| represents a generic filter structure that EventFilter knows how
+  // to filter events with. A typical filter instance will look like
+  //
+  // {
+  //   url: [{hostSuffix: 'google.com'}],
+  //   tabId: 5
+  // }
+  EventListener(const std::string& event_name,
+                const std::string& extension_id,
+                content::RenderProcessHost* process,
+                scoped_ptr<DictionaryValue> filter);
+  ~EventListener();
+
+  bool Equals(const EventListener* other) const;
+
+  scoped_ptr<EventListener> Copy() const;
+
+  const std::string event_name;
+  const std::string extension_id;
+  content::RenderProcessHost* process;
+  scoped_ptr<DictionaryValue> filter;
+  int matcher_id;

[battre, 2012/06/19 14:26:23]

nit: replace int with the correct typedef?

[koz (OOO until 15th September), 2012/06/20 08:05:56]

Done.

+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(EventListener);
+};
+
+// Holds listeners for extension events and can answer questions about which
+// listeners are interested in what events.
+class EventListenerMap {
+ public:
+  typedef std::vector<linked_ptr<EventListener> > ListenerList;
+
+  class Delegate {
+   public:
+    virtual void OnListenerAdded(const EventListener* listener) = 0;
+    virtual void OnListenerRemoved(const EventListener* listener) = 0;
+  };
+
+  explicit EventListenerMap(Delegate* delegate);
+  ~EventListenerMap();
+
+  // Add a listener for a particular event. GetEventListeners() will include a
+  // weak pointer to |listener| in its results if passed a relevant
+  // ExtensionEvent.

[battre, 2012/06/19 14:26:23]

Return value?

[koz (OOO until 15th September), 2012/06/20 08:05:56]

Done.

+  bool AddListener(scoped_ptr<EventListener> listener);
+
+  // Remove a listener that .Equals() |listener|.

[battre, 2012/06/19 14:26:23]

Return value?

[koz (OOO until 15th September), 2012/06/20 08:05:56]

Done.

+  bool RemoveListener(const EventListener* listener);
+
+  // Returns the set of listeners that want to be notified of |event|.
+  std::set<const EventListener*> GetEventListeners(
+      const ExtensionEvent& event);
+
+  // Removes all listeners with process equal to |process|.
+  void RemoveListenersForProcess(const content::RenderProcessHost* process);
+
+  // Returns true if there are any listeners on the event named |event_name|.
+  bool HasListenerForEvent(const std::string& event_name);
+
+  // Returns true if there are any listeners on |event_name| from
+  // |extension_id|.
+  bool HasListenerForExtension(const std::string& extension_id,
+                               const std::string& event_name);
+
+  // Returns true if this map contains an EventListener that .Equals()
+  // |listener|.
+  bool HasListener(const EventListener* listener);
+
+  // Returns true if there is a listener for |extension_id| in |process|.
+  bool HasProcessListener(content::RenderProcessHost* process,
+                          const std::string& extension_id);
+
+  // Removes any lazy listeners that |extension_id| has added.
+  void RemoveLazyListenersFor(const std::string& extension_id);

[battre, 2012/06/19 14:26:23]

RemoveLazyListenersForExtension(...)? In the unit tests I was wondering what the
string parameter was.

[koz (OOO until 15th September), 2012/06/20 08:05:56]

Done.

+
+  // Adds lazy listeners as described by |unfiltered| and |filtered|, which
+  // contain serialised descriptions of listeners. We can only load lazy
+  // listeners in this fashion, because there is no way to serialise a
+  // RenderProcessHost*.

[battre, 2012/06/19 14:26:23]

The meaning of |unfiltered| and |filtered| remains unclear to me.

[koz (OOO until 15th September), 2012/06/20 08:05:56]

I've added a bit more explanation.

+  void AddLazyListenersFromPreferences(
+      const std::string& extension_id,
+      const std::set<std::string>& unfiltered,
+      const DictionaryValue& filtered);
+
+ private:
+  typedef std::map<std::string, ListenerList> ListenerMap;

[battre, 2012/06/19 14:26:23]

Can you add a comment that the key is an event name?

[koz (OOO until 15th September), 2012/06/20 08:05:56]

Done.

+
+  void CleanupListener(EventListener* listener);
+  bool IsFilteredEvent(const ExtensionEvent& event) const;
+  scoped_ptr<EventMatcher> ParseEventMatcher(DictionaryValue* filter_dict);
+
+  // Listens for removals from this map.
+  Delegate* delegate_;
+
+  std::set<std::string> filtered_events_;
+  ListenerMap listeners_;
+
+  std::map<int, EventListener*> listeners_by_matcher_id_;

[battre, 2012/06/19 14:26:23]

nit: replace int with typedef?

[koz (OOO until 15th September), 2012/06/20 08:05:56]

Done.

+
+  EventFilter event_filter_;
+
+  DISALLOW_COPY_AND_ASSIGN(EventListenerMap);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_EVENT_LISTENER_MAP_H_