98 lines
3.3 KiB
Objective-C
98 lines
3.3 KiB
Objective-C
//
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// Copyright (c) 2016 Google Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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#import "FirebaseDatabaseUI/Sources/Public/FirebaseDatabaseUI/FUIQueryObserver.h"
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@interface FUIQueryObserver ()
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@property (nonatomic, readonly) NSMutableSet<NSNumber *> *handles;
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@property (nonatomic, readwrite) FIRDataSnapshot *contents;
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@end
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@implementation FUIQueryObserver
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- (instancetype)init {
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self = [self initWithQuery:(id _Nonnull)nil]; // silence a clang warning
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__unused id value = self; // silence an analyzer warning
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NSException *e =
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[NSException exceptionWithName:@"FIRUnavailableMethodException"
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reason:@"-init is unavailable. Please use the designated initializer instead."
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userInfo:nil];
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@throw e;
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}
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- (instancetype)initWithQuery:(id<FUIDataObservable>)query {
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self = [super init];
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if (self != nil) {
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_query = query;
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_handles = [NSMutableSet setWithCapacity:4];
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}
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return self;
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}
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+ (FUIQueryObserver *)observerForQuery:(id<FUIDataObservable>)query
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completion:(void (^)(FUIQueryObserver *obs,
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FIRDataSnapshot *snap,
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NSError *error))completion {
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FUIQueryObserver *obs = [[FUIQueryObserver alloc] initWithQuery:query];
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void (^observerBlock)(FIRDataSnapshot *, NSString *) = ^(FIRDataSnapshot *snap,
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NSString *previous) {
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obs.contents = snap;
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completion(obs, snap, nil);
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};
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void (^cancelBlock)(NSError *) = ^(NSError *error) {
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completion(obs, nil, error);
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};
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[obs observeEventType:FIRDataEventTypeValue
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andPreviousSiblingKeyWithBlock:observerBlock withCancelBlock:cancelBlock];
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return obs;
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}
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- (void)observeEventType:(FIRDataEventType)eventType
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andPreviousSiblingKeyWithBlock:(void (^)(FIRDataSnapshot *snapshot, NSString *__nullable prevKey))block
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withCancelBlock:(nullable void (^)(NSError* error))cancelBlock {
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FIRDatabaseHandle observerHandle = [self.query observeEventType:eventType
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andPreviousSiblingKeyWithBlock:block
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withCancelBlock:cancelBlock];
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NSNumber *handle = @(observerHandle);
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if ([self.handles containsObject:handle]) {
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[self.query removeObserverWithHandle:handle.unsignedIntegerValue];
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}
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[self.handles addObject:handle];
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}
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- (void)dealloc {
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[self removeAllObservers];
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}
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- (void)removeAllObservers {
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for (NSNumber *handle in _handles) {
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[_query removeObserverWithHandle:handle.unsignedIntegerValue];
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}
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}
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- (BOOL)isEqual:(id)object {
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if (![object isKindOfClass:[self class]]) { return NO; }
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FUIQueryObserver *obs = object;
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return [self.query isEqual:obs.query];
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}
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@end
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