chromium/extensions/renderer/bindings/api_event_listeners.h

// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef EXTENSIONS_RENDERER_BINDINGS_API_EVENT_LISTENERS_H_
#define EXTENSIONS_RENDERER_BINDINGS_API_EVENT_LISTENERS_H_

#include <string>
#include <vector>

#include "base/functional/callback.h"
#include "base/memory/raw_ptr.h"
#include "base/values.h"
#include "extensions/common/mojom/event_dispatcher.mojom-forward.h"
#include "extensions/renderer/bindings/api_binding_types.h"
#include "v8/include/v8.h"

namespace extensions {
class ListenerTracker;

// A base class to hold listeners for a given event. This allows for adding,
// removing, and querying listeners in the list, and calling a callback when
// transitioning from 0 -> 1 or 1 -> 0 listeners.
class APIEventListeners { … };

// A listener list implementation that doesn't support filtering. Each event
// dispatched is dispatched to all the associated listeners.
class UnfilteredEventListeners final : public APIEventListeners { … };

// A listener list implementation that supports filtering. Events should only
// be dispatched to those listeners whose filters match. Additionally, the
// updated callback is triggered any time a listener with a new filter is
// added, or the last listener with a given filter is removed.
class FilteredEventListeners final : public APIEventListeners { … };

}  // namespace extensions

#endif  // EXTENSIONS_RENDERER_BINDINGS_API_EVENT_LISTENERS_H_