blob: 1f16888c5dc13cde5b04482b9c99089bf08ca9fe (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
|
/*
* 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 "FSparseSnapshotTree.h"
#import "FChildrenNode.h"
@interface FSparseSnapshotTree () {
id<FNode> value;
NSMutableDictionary* children;
}
@end
@implementation FSparseSnapshotTree
- (id) init {
self = [super init];
if (self) {
value = nil;
children = nil;
}
return self;
}
- (id<FNode>) findPath:(FPath *)path {
if (value != nil) {
return [value getChild:path];
} else if (![path isEmpty] && children != nil) {
NSString* childKey = [path getFront];
path = [path popFront];
FSparseSnapshotTree* childTree = children[childKey];
if (childTree != nil) {
return [childTree findPath:path];
} else {
return nil;
}
} else {
return nil;
}
}
- (void) rememberData:(id<FNode>)data onPath:(FPath *)path {
if ([path isEmpty]) {
value = data;
children = nil;
} else if (value != nil) {
value = [value updateChild:path withNewChild:data];
} else {
if (children == nil) {
children = [[NSMutableDictionary alloc] init];
}
NSString* childKey = [path getFront];
if (children[childKey] == nil) {
children[childKey] = [[FSparseSnapshotTree alloc] init];
}
FSparseSnapshotTree* child = children[childKey];
path = [path popFront];
[child rememberData:data onPath:path];
}
}
- (BOOL) forgetPath:(FPath *)path {
if ([path isEmpty]) {
value = nil;
children = nil;
return YES;
} else {
if (value != nil) {
if ([value isLeafNode]) {
// non-empty path at leaf. the path leads to nowhere
return NO;
} else {
id<FNode> tmp = value;
value = nil;
[tmp enumerateChildrenUsingBlock:^(NSString *key, id<FNode> node, BOOL *stop) {
[self rememberData:node onPath:[[FPath alloc] initWith:key]];
}];
// we've cleared out the value and set children. Call ourself again to hit the next case
return [self forgetPath:path];
}
} else if (children != nil) {
NSString* childKey = [path getFront];
path = [path popFront];
if (children[childKey] != nil) {
FSparseSnapshotTree* child = children[childKey];
BOOL safeToRemove = [child forgetPath:path];
if (safeToRemove) {
[children removeObjectForKey:childKey];
}
}
if ([children count] == 0) {
children = nil;
return YES;
} else {
return NO;
}
} else {
return YES;
}
}
}
- (void) forEachTreeAtPath:(FPath *)prefixPath do:(fbt_void_path_node)func {
if (value != nil) {
func(prefixPath, value);
} else {
[self forEachChild:^(NSString* key, FSparseSnapshotTree* tree) {
FPath* path = [prefixPath childFromString:key];
[tree forEachTreeAtPath:path do:func];
}];
}
}
- (void) forEachChild:(fbt_void_nsstring_sstree)func {
if (children != nil) {
for (NSString* key in children) {
FSparseSnapshotTree* tree = [children objectForKey:key];
func(key, tree);
}
}
}
@end
|
