Files

127 lines
3.7 KiB
Objective-C

/*
* 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 "FirebaseDatabase/Sources/FPriorityIndex.h"
#import "FirebaseDatabase/Sources/FMaxNode.h"
#import "FirebaseDatabase/Sources/FNamedNode.h"
#import "FirebaseDatabase/Sources/Snapshot/FEmptyNode.h"
#import "FirebaseDatabase/Sources/Snapshot/FLeafNode.h"
#import "FirebaseDatabase/Sources/Snapshot/FNode.h"
#import "FirebaseDatabase/Sources/Utilities/FUtilities.h"
// TODO: Abstract into some common base class?
@implementation FPriorityIndex
- (NSComparisonResult)compareKey:(NSString *)key1
andNode:(id<FNode>)node1
toOtherKey:(NSString *)key2
andNode:(id<FNode>)node2 {
id<FNode> child1 = [node1 getPriority];
id<FNode> child2 = [node2 getPriority];
NSComparisonResult indexCmp = [child1 compare:child2];
if (indexCmp == NSOrderedSame) {
return [FUtilities compareKey:key1 toKey:key2];
} else {
return indexCmp;
}
}
- (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 !node.getPriority.isEmpty;
}
- (BOOL)indexedValueChangedBetween:(id<FNode>)oldNode and:(id<FNode>)newNode {
id<FNode> oldValue = [oldNode getPriority];
id<FNode> newValue = [newNode getPriority];
return ![oldValue isEqual:newValue];
}
- (FNamedNode *)minPost {
return FNamedNode.min;
}
- (FNamedNode *)maxPost {
return [self makePost:[FMaxNode maxNode] name:[FUtilities maxName]];
}
- (FNamedNode *)makePost:(id<FNode>)indexValue name:(NSString *)name {
id<FNode> node = [[FLeafNode alloc] initWithValue:@"[PRIORITY-POST]"
withPriority:indexValue];
return [[FNamedNode alloc] initWithName:name andNode:node];
}
- (NSString *)queryDefinition {
return @".priority";
}
- (NSString *)description {
return @"FPriorityIndex";
}
- (id)copyWithZone:(NSZone *)zone {
// Safe since we're immutable.
return self;
}
- (BOOL)isEqual:(id)other {
return [other isKindOfClass:[FPriorityIndex class]];
}
- (NSUInteger)hash {
// chosen by a fair dice roll. Guaranteed to be random
return 3155577;
}
+ (id<FIndex>)priorityIndex {
static id<FIndex> index;
static dispatch_once_t once;
dispatch_once(&once, ^{
index = [[FPriorityIndex alloc] init];
});
return index;
}
@end