148 lines
4.1 KiB
Objective-C
148 lines
4.1 KiB
Objective-C
/*
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* Copyright 2017 Google
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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 <Foundation/Foundation.h>
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NS_ASSUME_NONNULL_BEGIN
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@class FIRDatabaseReference;
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/**
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* A FIRDataSnapshot contains data from a Firebase Database location. Any time you read
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* Firebase data, you receive the data as a FIRDataSnapshot.
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*
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* FIRDataSnapshots are passed to the blocks you attach with observeEventType:withBlock: or observeSingleEvent:withBlock:.
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* They are efficiently-generated immutable copies of the data at a Firebase Database location.
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* They can't be modified and will never change. To modify data at a location,
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* use a FIRDatabaseReference (e.g. with setValue:).
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*/
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NS_SWIFT_NAME(DataSnapshot)
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@interface FIRDataSnapshot : NSObject
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#pragma mark - Navigating and inspecting a snapshot
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/**
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* Gets a FIRDataSnapshot for the location at the specified relative path.
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* The relative path can either be a simple child key (e.g. 'fred')
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* or a deeper slash-separated path (e.g. 'fred/name/first'). If the child
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* location has no data, an empty FIRDataSnapshot is returned.
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*
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* @param childPathString A relative path to the location of child data.
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* @return The FIRDataSnapshot for the child location.
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*/
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- (FIRDataSnapshot *)childSnapshotForPath:(NSString *)childPathString;
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/**
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* Return YES if the specified child exists.
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*
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* @param childPathString A relative path to the location of a potential child.
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* @return YES if data exists at the specified childPathString, else NO.
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*/
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- (BOOL) hasChild:(NSString *)childPathString;
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/**
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* Return YES if the DataSnapshot has any children.
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*
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* @return YES if this snapshot has any children, else NO.
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*/
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- (BOOL) hasChildren;
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/**
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* Return YES if the DataSnapshot contains a non-null value.
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*
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* @return YES if this snapshot contains a non-null value, else NO.
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*/
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- (BOOL) exists;
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#pragma mark - Data export
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/**
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* Returns the raw value at this location, coupled with any metadata, such as priority.
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*
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* Priorities, where they exist, are accessible under the ".priority" key in instances of NSDictionary.
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* For leaf locations with priorities, the value will be under the ".value" key.
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*/
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- (id __nullable) valueInExportFormat;
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#pragma mark - Properties
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/**
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* Returns the contents of this data snapshot as native types.
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*
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* Data types returned:
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* + NSDictionary
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* + NSArray
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* + NSNumber (also includes booleans)
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* + NSString
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*
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* @return The data as a native object.
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*/
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@property (strong, readonly, nonatomic, nullable) id value;
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/**
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* Gets the number of children for this DataSnapshot.
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*
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* @return An integer indicating the number of children.
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*/
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@property (readonly, nonatomic) NSUInteger childrenCount;
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/**
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* Gets a FIRDatabaseReference for the location that this data came from.
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*
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* @return A FIRDatabaseReference instance for the location of this data.
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*/
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@property (nonatomic, readonly, strong) FIRDatabaseReference * ref;
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/**
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* The key of the location that generated this FIRDataSnapshot.
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*
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* @return An NSString containing the key for the location of this FIRDataSnapshot.
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*/
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@property (strong, readonly, nonatomic) NSString* key;
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/**
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* An iterator for snapshots of the child nodes in this snapshot.
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* You can use the native for..in syntax:
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*
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* for (FIRDataSnapshot* child in snapshot.children) {
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* ...
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* }
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*
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* @return An NSEnumerator of the children.
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*/
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@property (strong, readonly, nonatomic) NSEnumerator<FIRDataSnapshot *>* children;
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/**
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* The priority of the data in this FIRDataSnapshot.
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*
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* @return The priority as a string, or nil if no priority was set.
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*/
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@property (strong, readonly, nonatomic, nullable) id priority;
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@end
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NS_ASSUME_NONNULL_END
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