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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 "FIndexedNode.h"
#import "FImmutableSortedSet.h"
#import "FIndex.h"
#import "FPriorityIndex.h"
#import "FKeyIndex.h"
#import "FChildrenNode.h"
static FImmutableSortedSet *FALLBACK_INDEX;
@interface FIndexedNode ()
@property (nonatomic, strong) id<FNode> node;
/**
* The indexed set is initialized lazily to prevent creation when it is not needed
*/
@property (nonatomic, strong) FImmutableSortedSet *indexed;
@property (nonatomic, strong) id<FIndex> index;
@end
@implementation FIndexedNode
+ (FImmutableSortedSet *)fallbackIndex {
static FImmutableSortedSet *fallbackIndex;
static dispatch_once_t once;
dispatch_once(&once, ^{
fallbackIndex = [[FImmutableSortedSet alloc] init];
});
return fallbackIndex;
}
+ (FIndexedNode *)indexedNodeWithNode:(id<FNode>)node
{
return [[FIndexedNode alloc] initWithNode:node index:[FPriorityIndex priorityIndex]];
}
+ (FIndexedNode *)indexedNodeWithNode:(id<FNode>)node index:(id<FIndex>)index
{
return [[FIndexedNode alloc] initWithNode:node index:index];
}
- (id)initWithNode:(id<FNode>)node index:(id<FIndex>)index
{
// Initialize indexed lazily
return [self initWithNode:node index:index indexed:nil];
}
- (id)initWithNode:(id<FNode>)node index:(id<FIndex>)index indexed:(FImmutableSortedSet *)indexed
{
self = [super init];
if (self != nil) {
self->_node = node;
self->_index = index;
self->_indexed = indexed;
}
return self;
}
- (void)ensureIndexed
{
if (!self.indexed) {
if ([self.index isEqual:[FKeyIndex keyIndex]]) {
self.indexed = [FIndexedNode fallbackIndex];
} else {
__block BOOL sawChild = NO;
[self.node enumerateChildrenUsingBlock:^(NSString *key, id<FNode> node, BOOL *stop) {
sawChild = sawChild || [self.index isDefinedOn:node];
*stop = sawChild;
}];
if (sawChild) {
NSMutableDictionary *dict = [NSMutableDictionary dictionary];
[self.node enumerateChildrenUsingBlock:^(NSString *key, id<FNode> node, BOOL *stop) {
FNamedNode *namedNode = [[FNamedNode alloc] initWithName:key andNode:node];
dict[namedNode] = [NSNull null];
}];
// Make sure to assign index here, because the comparator will be retained and using self will cause a
// cycle
id<FIndex> index = self.index;
self.indexed = [FImmutableSortedSet setWithKeysFromDictionary:dict
comparator:^NSComparisonResult(FNamedNode *namedNode1, FNamedNode *namedNode2) {
return [index compareNamedNode:namedNode1 toNamedNode:namedNode2];
}];
} else {
self.indexed = [FIndexedNode fallbackIndex];
}
}
}
}
- (BOOL)hasIndex:(id<FIndex>)index
{
return [self.index isEqual:index];
}
- (FIndexedNode *)updateChild:(NSString *)key withNewChild:(id<FNode>)newChildNode
{
id<FNode> newNode = [self.node updateImmediateChild:key withNewChild:newChildNode];
if (self.indexed == [FIndexedNode fallbackIndex] && ![self.index isDefinedOn:newChildNode]) {
// doesn't affect the index, no need to create an index
return [[FIndexedNode alloc] initWithNode:newNode index:self.index indexed:[FIndexedNode fallbackIndex]];
} else if (!self.indexed || self.indexed == [FIndexedNode fallbackIndex]) {
// No need to index yet, index lazily
return [[FIndexedNode alloc] initWithNode:newNode index:self.index];
} else {
id<FNode> oldChild = [self.node getImmediateChild:key];
FImmutableSortedSet *newIndexed = [self.indexed removeObject:[FNamedNode nodeWithName:key node:oldChild]];
if (![newChildNode isEmpty]) {
newIndexed = [newIndexed addObject:[FNamedNode nodeWithName:key node:newChildNode]];
}
return [[FIndexedNode alloc] initWithNode:newNode index:self.index indexed:newIndexed];
}
}
- (FIndexedNode *)updatePriority:(id<FNode>)priority
{
return [[FIndexedNode alloc] initWithNode:[self.node updatePriority:priority]
index:self.index
indexed:self.indexed];
}
- (FNamedNode *)firstChild
{
if (![self.node isKindOfClass:[FChildrenNode class]]) {
return nil;
} else {
[self ensureIndexed];
if (self.indexed == [FIndexedNode fallbackIndex]) {
return [((FChildrenNode *)self.node) firstChild];
} else {
return self.indexed.firstObject;
}
}
}
- (FNamedNode *)lastChild
{
if (![self.node isKindOfClass:[FChildrenNode class]]) {
return nil;
} else {
[self ensureIndexed];
if (self.indexed == [FIndexedNode fallbackIndex]) {
return [((FChildrenNode *)self.node) lastChild];
} else {
return self.indexed.lastObject;
}
}
}
- (NSString *)predecessorForChildKey:(NSString *)childKey childNode:(id<FNode>)childNode index:(id<FIndex>)index
{
if (![self.index isEqual:index]) {
[NSException raise:NSInvalidArgumentException format:@"Index not available in IndexedNode!"];
}
[self ensureIndexed];
if (self.indexed == [FIndexedNode fallbackIndex]) {
return [self.node predecessorChildKey:childKey];
} else {
FNamedNode *node = [self.indexed predecessorEntry:[FNamedNode nodeWithName:childKey node:childNode]];
return node.name;
}
}
- (void)enumerateChildrenReverse:(BOOL)reverse usingBlock:(void (^)(NSString *, id<FNode>, BOOL *))block
{
[self ensureIndexed];
if (self.indexed == [FIndexedNode fallbackIndex]) {
[self.node enumerateChildrenReverse:reverse usingBlock:block];
} else {
[self.indexed enumerateObjectsReverse:reverse usingBlock:^(FNamedNode *namedNode, BOOL *stop) {
block(namedNode.name, namedNode.node, stop);
}];
}
}
- (NSEnumerator *)childEnumerator
{
[self ensureIndexed];
if (self.indexed == [FIndexedNode fallbackIndex]) {
return [self.node childEnumerator];
} else {
return [self.indexed objectEnumerator];
}
}
@end
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