101 lines
2.6 KiB
Objective-C
101 lines
2.6 KiB
Objective-C
/**
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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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#import "RCTEventEmitter.h"
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#import "RCTAssert.h"
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#import "RCTUtils.h"
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#import "RCTLog.h"
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@implementation RCTEventEmitter
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{
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NSInteger _listenerCount;
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}
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+ (NSString *)moduleName
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{
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return @"";
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}
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+ (void)initialize
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{
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if (self != [RCTEventEmitter class]) {
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RCTAssert(RCTClassOverridesInstanceMethod(self, @selector(supportedEvents)),
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@"You must override the `supportedEvents` method of %@", self);
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}
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}
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- (NSArray<NSString *> *)supportedEvents
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{
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return nil;
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}
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- (void)sendEventWithName:(NSString *)eventName body:(id)body
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{
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RCTAssert(_bridge != nil, @"Error when sending event: %@ with body: %@. "
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"Bridge is not set. This is probably because you've "
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"explicitly synthesized the bridge in %@, even though it's inherited "
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"from RCTEventEmitter.", eventName, body, [self class]);
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if (RCT_DEBUG && ![[self supportedEvents] containsObject:eventName]) {
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RCTLogError(@"`%@` is not a supported event type for %@. Supported events are: `%@`",
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eventName, [self class], [[self supportedEvents] componentsJoinedByString:@"`, `"]);
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}
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if (_listenerCount > 0) {
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[_bridge enqueueJSCall:@"RCTDeviceEventEmitter"
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method:@"emit"
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args:body ? @[eventName, body] : @[eventName]
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completion:NULL];
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} else {
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RCTLogWarn(@"Sending `%@` with no listeners registered.", eventName);
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}
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}
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- (void)startObserving
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{
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// Does nothing
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}
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- (void)stopObserving
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{
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// Does nothing
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}
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- (void)dealloc
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{
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if (_listenerCount > 0) {
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[self stopObserving];
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}
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}
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RCT_EXPORT_METHOD(addListener:(NSString *)eventName)
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{
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if (RCT_DEBUG && ![[self supportedEvents] containsObject:eventName]) {
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RCTLogError(@"`%@` is not a supported event type for %@. Supported events are: `%@`",
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eventName, [self class], [[self supportedEvents] componentsJoinedByString:@"`, `"]);
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}
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_listenerCount++;
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if (_listenerCount == 1) {
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[self startObserving];
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}
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}
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RCT_EXPORT_METHOD(removeListeners:(double)count)
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{
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int currentCount = (int)count;
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if (RCT_DEBUG && currentCount > _listenerCount) {
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RCTLogError(@"Attempted to remove more %@ listeners than added", [self class]);
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}
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_listenerCount = MAX(_listenerCount - currentCount, 0);
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if (_listenerCount == 0) {
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[self stopObserving];
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}
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}
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@end
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