diff options
author | Paul Beusterien <paulbeusterien@google.com> | 2017-05-15 12:27:07 -0700 |
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committer | Paul Beusterien <paulbeusterien@google.com> | 2017-05-15 12:27:07 -0700 |
commit | 98ba64449a632518bd2b86fe8d927f4a960d3ddc (patch) | |
tree | 131d9c4272fa6179fcda6c5a33fcb3b1bd57ad2e /Firebase/Database/FKeyIndex.m | |
parent | 32461366c9e204a527ca05e6e9b9404a2454ac51 (diff) |
Initial
Diffstat (limited to 'Firebase/Database/FKeyIndex.m')
-rw-r--r-- | Firebase/Database/FKeyIndex.m | 115 |
1 files changed, 115 insertions, 0 deletions
diff --git a/Firebase/Database/FKeyIndex.m b/Firebase/Database/FKeyIndex.m new file mode 100644 index 0000000..68ad461 --- /dev/null +++ b/Firebase/Database/FKeyIndex.m @@ -0,0 +1,115 @@ +/* + * 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 "FKeyIndex.h" +#import "FNamedNode.h" +#import "FSnapshotUtilities.h" +#import "FUtilities.h" +#import "FEmptyNode.h" + +@interface FKeyIndex () + +@property (nonatomic, strong) FNamedNode *maxPost; + +@end + +@implementation FKeyIndex + +- (id)init { + self = [super init]; + if (self) { + self.maxPost = [[FNamedNode alloc] initWithName:[FUtilities maxName] andNode:[FEmptyNode emptyNode]]; + } + return self; + +} + +- (NSComparisonResult) compareKey:(NSString *)key1 + andNode:(id<FNode>)node1 + toOtherKey:(NSString *)key2 + andNode:(id<FNode>)node2 +{ + return [FUtilities compareKey:key1 toKey:key2]; +} + +- (NSComparisonResult) compareKey:(NSString *)key1 + andNode:(id<FNode>)node1 + toOtherKey:(NSString *)key2 + andNode:(id<FNode>)node2 + reverse:(BOOL)reverse +{ + if (reverse) { + return [self compareKey:key2 andNode:node2 toOtherKey:key1 andNode:node1]; + } else { + return [self compareKey:key1 andNode:node1 toOtherKey:key2 andNode:node2]; + } +} + +- (NSComparisonResult) compareNamedNode:(FNamedNode *)namedNode1 toNamedNode:(FNamedNode *)namedNode2 +{ + return [self compareKey:namedNode1.name andNode:namedNode1.node toOtherKey:namedNode2.name andNode:namedNode2.node]; +} + +- (BOOL)isDefinedOn:(id <FNode>)node { + return YES; +} + +- (BOOL)indexedValueChangedBetween:(id <FNode>)oldNode and:(id <FNode>)newNode { + return NO; // The key for a node never changes. +} + +- (FNamedNode *)minPost { + return [FNamedNode min]; +} + +- (FNamedNode *)makePost:(id<FNode>)indexValue name:(NSString*)name { + NSString *key = indexValue.val; + NSAssert([key isKindOfClass:[NSString class]], @"KeyIndex indexValue must always be a string."); + // We just use empty node, but it'll never be compared, since our comparator only looks at name. + return [[FNamedNode alloc] initWithName:key andNode:[FEmptyNode emptyNode]]; +} + +- (NSString *) queryDefinition { + return @".key"; +} + +- (NSString *) description { + return @"FKeyIndex"; +} + +- (id)copyWithZone:(NSZone *)zone { + return self; +} + +- (BOOL) isEqual:(id)other { + // since we're a singleton. + return (other == self); +} + +- (NSUInteger) hash { + return [@".key" hash]; +} + + ++ (id<FIndex>) keyIndex { + static id<FIndex> keyIndex; + static dispatch_once_t once; + dispatch_once(&once, ^{ + keyIndex = [[FKeyIndex alloc] init]; + }); + return keyIndex; +} +@end |