108 lines
4.4 KiB
Objective-C
108 lines
4.4 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 "FRangeMerge.h"
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#import "FEmptyNode.h"
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@interface FRangeMerge ()
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@property (nonatomic, strong) FPath *optExclusiveStart;
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@property (nonatomic, strong) FPath *optInclusiveEnd;
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@property (nonatomic, strong) id<FNode> updates;
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@end
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@implementation FRangeMerge
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- (instancetype)initWithStart:(FPath *)start end:(FPath *)end updates:(id<FNode>)updates {
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self = [super init];
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if (self != nil) {
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self->_optExclusiveStart = start;
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self->_optInclusiveEnd = end;
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self->_updates = updates;
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}
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return self;
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}
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- (id<FNode>)applyToNode:(id<FNode>)node {
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return [self updateRangeInNode:[FPath empty] node:node updates:self.updates];
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}
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- (id<FNode>)updateRangeInNode:(FPath *)currentPath node:(id<FNode>)node updates:(id<FNode>)updates {
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NSComparisonResult startComparison = (self.optExclusiveStart == nil) ? NSOrderedDescending : [currentPath compare:self.optExclusiveStart];
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NSComparisonResult endComparison = (self.optInclusiveEnd == nil) ? NSOrderedAscending : [currentPath compare:self.optInclusiveEnd];
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BOOL startInNode = self.optExclusiveStart != nil && [currentPath contains:self.optExclusiveStart];
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BOOL endInNode = self.optInclusiveEnd != nil && [currentPath contains:self.optInclusiveEnd];
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if (startComparison == NSOrderedDescending && endComparison == NSOrderedAscending && !endInNode) {
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// child is completly contained
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return updates;
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} else if (startComparison == NSOrderedDescending && endInNode && [updates isLeafNode]) {
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return updates;
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} else if (startComparison == NSOrderedDescending && endComparison == NSOrderedSame) {
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NSAssert(endInNode, @"End not in node");
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NSAssert(![updates isLeafNode], @"Found leaf node update, this case should have been handled above.");
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if ([node isLeafNode]) {
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// Update node was not a leaf node, so we can delete it
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return [FEmptyNode emptyNode];
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} else {
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// Unaffected by range, ignore
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return node;
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}
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} else if (startInNode || endInNode) {
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// There is a partial update we need to do, so collect all relevant children
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NSMutableSet *allChildren = [NSMutableSet set];
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[node enumerateChildrenUsingBlock:^(NSString *key, id<FNode> node, BOOL *stop) {
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[allChildren addObject:key];
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}];
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[updates enumerateChildrenUsingBlock:^(NSString *key, id<FNode> node, BOOL *stop) {
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[allChildren addObject:key];
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}];
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__block id<FNode> newNode = node;
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void (^action)(id, BOOL *) = ^void(NSString *key, BOOL *stop) {
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id<FNode> currentChild = [node getImmediateChild:key];
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id<FNode> updatedChild = [self updateRangeInNode:[currentPath childFromString:key]
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node:currentChild
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updates:[updates getImmediateChild:key]];
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// Only need to update if the node changed
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if (updatedChild != currentChild) {
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newNode = [newNode updateImmediateChild:key withNewChild:updatedChild];
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}
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};
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[allChildren enumerateObjectsUsingBlock:action];
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// Add priority last, so the node is not empty when applying
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if (!updates.getPriority.isEmpty || !node.getPriority.isEmpty) {
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BOOL stop = NO;
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action(@".priority", &stop);
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}
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return newNode;
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} else {
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// Unaffected by this range
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NSAssert(endComparison == NSOrderedDescending || startComparison <= NSOrderedSame, @"Invalid range for update");
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return node;
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}
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}
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- (NSString *)description {
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return [NSString stringWithFormat:@"RangeMerge (optExclusiveStart = %@, optExclusiveEng = %@, updates = %@)",
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self.optExclusiveStart, self.optInclusiveEnd, self.updates];
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}
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@end
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