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/*
* Copyright 2017 Google
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#import "FEventEmitter.h"
#import "FUtilities.h"
#import "FRepoManager.h"
#import "FIRDatabaseQuery_Private.h"
@interface FEventListener : NSObject
@property (nonatomic, copy) fbt_void_id userCallback;
@property (nonatomic) FIRDatabaseHandle handle;
@end
@implementation FEventListener
@synthesize userCallback;
@synthesize handle;
@end
@interface FEventEmitter ()
@property (nonatomic, strong) NSArray *allowedEvents;
@property (nonatomic, strong) NSMutableDictionary *listeners;
@property (nonatomic, strong) dispatch_queue_t queue;
@end
@implementation FEventEmitter
@synthesize allowedEvents;
@synthesize listeners;
- (id) initWithAllowedEvents:(NSArray *)theAllowedEvents queue:(dispatch_queue_t)queue {
if (theAllowedEvents == nil || [theAllowedEvents count] == 0) {
@throw [NSException exceptionWithName:@"AllowedEventsValidation" reason:@"FEventEmitters must be initialized with at least one valid event." userInfo:nil];
}
self = [super init];
if (self) {
self.allowedEvents = [theAllowedEvents copy];
self.listeners = [[NSMutableDictionary alloc] init];
self.queue = queue;
}
return self;
}
- (id) getInitialEventForType:(NSString *)eventType {
@throw [NSException exceptionWithName:NSInternalInconsistencyException reason:@"You must override getInitialEvent: when subclassing FEventEmitter" userInfo:nil];
}
- (void) triggerEventType:(NSString *)eventType data:(id)data {
[self validateEventType:eventType];
NSMutableDictionary *eventTypeListeners = [self.listeners objectForKey:eventType];
for (FEventListener *listener in eventTypeListeners) {
[self triggerListener:listener withData:data];
}
}
- (void) triggerListener:(FEventListener *)listener withData:(id)data {
// TODO, should probably get this from FRepo or something although it ends up being the same. (Except maybe for testing)
if (listener.userCallback) {
dispatch_async(self.queue, ^{
listener.userCallback(data);
});
}
}
- (FIRDatabaseHandle)observeEventType:(NSString *)eventType withBlock:(fbt_void_id)block {
[self validateEventType:eventType];
// Create listener
FEventListener *listener = [[FEventListener alloc] init];
listener.handle = [[FUtilities LUIDGenerator] integerValue];
listener.userCallback = block; // copies block automatically
dispatch_async([FIRDatabaseQuery sharedQueue], ^{
[self addEventListener:listener forEventType:eventType];
});
return listener.handle;
}
- (void) addEventListener:(FEventListener *)listener forEventType:(NSString *)eventType {
// Get or initializer listeners map [FIRDatabaseHandle -> callback block] for eventType
NSMutableArray *eventTypeListeners = [self.listeners objectForKey:eventType];
if (eventTypeListeners == nil) {
eventTypeListeners = [[NSMutableArray alloc] init];
[self.listeners setObject:eventTypeListeners forKey:eventType];
}
// Add listener and fire the current event for this listener
[eventTypeListeners addObject:listener];
id initialData = [self getInitialEventForType:eventType];
[self triggerListener:listener withData:initialData];
}
- (void) removeObserverForEventType:(NSString *)eventType withHandle:(FIRDatabaseHandle)handle {
[self validateEventType:eventType];
dispatch_async([FIRDatabaseQuery sharedQueue], ^{
[self removeEventListenerWithHandle:handle forEventType:eventType];
});
}
- (void)removeEventListenerWithHandle:(FIRDatabaseHandle)handle forEventType:(NSString *)eventType {
NSMutableArray *eventTypeListeners = [self.listeners objectForKey:eventType];
for (FEventListener *listener in [eventTypeListeners copy]) {
if (handle == NSNotFound || handle == listener.handle) {
[eventTypeListeners removeObject:listener];
}
}
}
- (void) validateEventType:(NSString *)eventType {
if ([self.allowedEvents indexOfObject:eventType] == NSNotFound) {
@throw [NSException exceptionWithName:@"InvalidEventType"
reason:[NSString stringWithFormat:@"%@ is not a valid event type. %@ is the list of valid events.",
eventType, self.allowedEvents]
userInfo:nil];
}
}
@end
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