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// Copyright 2017 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_RENDERER_EVENT_BOOKKEEPER_H_
#define EXTENSIONS_RENDERER_EVENT_BOOKKEEPER_H_
#include <map>
#include <memory>
#include <set>
#include <string>
#include "base/macros.h"
#include "extensions/common/event_filter.h"
#include "extensions/common/extension_id.h"
namespace base {
class DictionaryValue;
}
namespace extensions {
class EventFilter;
class ScriptContext;
class ValueCounter;
// Class to manage thread (main or worker) specific event global data.
//
// TODO(lazyboy): This class could use an IPCMessageSender to also notify the
// browser/ about the changes in the event data it manages. Currently this is
// done from EventBindings, i.e. EventBindings updates/queries EventBookkeeper
// and then notifies the browser/.
// TODO(devlin/lazyboy): This class is only necessary with JS-based bindings.
// Remove it when Native bindings launch.
class EventBookkeeper {
public:
EventBookkeeper();
~EventBookkeeper();
// Returns the instance of EventBookkeeper that belongs to current thread.
static EventBookkeeper* Get();
// Increments the number of event-listeners for the given |event_name| and
// ScriptContext. Returns the count after the increment.
int IncrementEventListenerCount(ScriptContext* script_context,
const std::string& event_name);
// Decrements the number of event-listeners for the given |event_name| and
// ScriptContext. Returns the count after the decrement.
int DecrementEventListenerCount(ScriptContext* script_context,
const std::string& event_name);
// Returns the EventFilter.
EventFilter& event_filter() { return event_filter_; }
// Adds a filter to |event_name| in |extension_id|, returning true if it
// was the first filter for that event in that extension.
bool AddFilter(const std::string& event_name,
const ExtensionId& extension_id,
const base::DictionaryValue& filter);
// Removes a filter from |event_name| in |extension_id|, returning true if it
// was the last filter for that event in that extension.
bool RemoveFilter(const std::string& event_name,
const ExtensionId& extension_id,
base::DictionaryValue* filter);
// Returns true if there is an event (managed or unmanaged) with the given
// context and event name.
bool HasListener(ScriptContext* script_context,
const std::string& event_name);
void AddUnmanagedEvent(ScriptContext* context, const std::string& event_name);
void RemoveUnmanagedEvent(ScriptContext* context,
const std::string& event_name);
void RemoveAllUnmanagedListeners(ScriptContext* context);
private:
using EventName = std::string;
// A map of event name to the number of contexts listening to that event.
using EventListenerCounts = std::map<EventName, int>;
// Maps context id -> (map of event name -> listener count).
using AllCounts = std::map<std::string, EventListenerCounts>;
using FilteredEventListenerKey = std::pair<ExtensionId, EventName>;
// A map of <extension id, event name> pair to listener counts.
using FilteredEventListenerCounts =
std::map<FilteredEventListenerKey, std::unique_ptr<ValueCounter>>;
// A map of context to name of events the context has.
using UnmanagedListenerMap = std::map<ScriptContext*, std::set<std::string>>;
// Used to notify the browser about event listeners when we transition between
// 0 and 1.
AllCounts listener_counts_;
// The event filter.
EventFilter event_filter_;
// A map of (extension ID, event name) pairs to the filtered listener counts
// for that pair. The map is used to keep track of which filters are in effect
// for which events. Used to notify the browser about filtered event
// listeners when we transition between 0 and 1.
FilteredEventListenerCounts filtered_listener_counts_;
// A collection of the unmanaged events (i.e., those for which the browser is
// not notified of changes) that have listeners, by context.
UnmanagedListenerMap unmanaged_listeners_;
DISALLOW_COPY_AND_ASSIGN(EventBookkeeper);
};
} // namespace extensions
#endif // EXTENSIONS_RENDERER_EVENT_BOOKKEEPER_H_
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