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516bf7bd94
Summary: The `EmitterSubscription.remove()` method was previously calling `this.subscriber.removeSubscription(this)` directly, bypassing the mechanism in `NativeEventEmitter` that keeps track of the number of subscriptions. This meant that native event modules (subclasses of `RCTEventEmitter`) would keep sending events even after all the listeners had been removed. This wasn't a huge overhead, since these modules are singletons and only send one message over the bridge per event, regardless of the number of listeners, but it's still undesirable. This fixes the problem by routing the `EmitterSubscription.remove()` method through the `EventEmitter` so that `NativeEventEmitter` can apply the additional native calls. I've also improved the architecture so that each `NativeEventEmitter` uses its own `EventEmitter`, but they currently all still share the same `EventSubscriptionVendor` so that legacy code which registers events via `RCTDeviceEventEmitter` still works. Reviewed By: vjeux Differential Revision: D3292361 fbshipit-source-id: d60e881d50351523d2112473703bea826641cdef
63 lines
1.8 KiB
JavaScript
63 lines
1.8 KiB
JavaScript
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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* @providesModule EmitterSubscription
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* @noflow
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* @typechecks
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*/
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'use strict';
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const EventSubscription = require('EventSubscription');
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import type EventEmitter from 'EventEmitter';
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import type EventSubscriptionVendor from 'EventSubscriptionVendor';
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/**
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* EmitterSubscription represents a subscription with listener and context data.
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*/
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class EmitterSubscription extends EventSubscription {
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emitter: EventEmitter;
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listener: Function;
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context: ?Object;
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/**
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* @param {EventEmitter} emitter - The event emitter that registered this
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* subscription
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* @param {EventSubscriptionVendor} subscriber - The subscriber that controls
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* this subscription
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* @param {function} listener - Function to invoke when the specified event is
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* emitted
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* @param {*} context - Optional context object to use when invoking the
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* listener
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*/
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constructor(
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emitter: EventEmitter,
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subscriber: EventSubscriptionVendor,
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listener: Function,
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context: ?Object
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) {
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super(subscriber);
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this.emitter = emitter;
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this.listener = listener;
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this.context = context;
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}
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/**
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* Removes this subscription from the emitter that registered it.
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* Note: we're overriding the `remove()` method of EventSubscription here
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* but deliberately not calling `super.remove()` as the responsibility
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* for removing the subscription lies with the EventEmitter.
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*/
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remove() {
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this.emitter.removeSubscription(this);
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}
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}
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module.exports = EmitterSubscription;
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