139 строки
3.1 KiB
Objective-C
139 строки
3.1 KiB
Objective-C
/*
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*/
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#import "RCTEventEmitter.h"
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#import "RCTAssert.h"
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#import "RCTLog.h"
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#import "RCTUtils.h"
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@implementation RCTEventEmitter {
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NSInteger _listenerCount;
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BOOL _observationDisabled;
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}
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@synthesize invokeJS = _invokeJS;
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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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[super initialize];
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if (self != [RCTEventEmitter class]) {
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RCTAssert(
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RCTClassOverridesInstanceMethod(self, @selector(supportedEvents)),
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@"You must override the `supportedEvents` method of %@",
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self);
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}
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}
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- (instancetype)initWithDisabledObservation
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{
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self = [super init];
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_observationDisabled = YES;
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return self;
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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(
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_bridge != nil || _invokeJS != nil,
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@"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.",
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eventName,
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body,
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[self class]);
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if (RCT_DEBUG && ![[self supportedEvents] containsObject:eventName]) {
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RCTLogError(
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@"`%@` is not a supported event type for %@. Supported events are: `%@`",
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eventName,
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[self class],
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[[self supportedEvents] componentsJoinedByString:@"`, `"]);
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}
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BOOL shouldEmitEvent = (_observationDisabled || _listenerCount > 0);
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if (shouldEmitEvent && _bridge) {
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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 if (shouldEmitEvent && _invokeJS) {
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_invokeJS(@"RCTDeviceEventEmitter", @"emit", body ? @[ eventName, body ] : @[ eventName ]);
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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)invalidate
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{
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if (_observationDisabled) {
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return;
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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 (_observationDisabled) {
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return;
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}
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if (RCT_DEBUG && ![[self supportedEvents] containsObject:eventName]) {
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RCTLogError(
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@"`%@` is not a supported event type for %@. Supported events are: `%@`",
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eventName,
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[self class],
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[[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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if (_observationDisabled) {
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return;
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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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