William Kurkian | ea86948 | 2019-04-09 15:16:11 -0400 | [diff] [blame] | 1 | // Copyright 2015 The etcd Authors |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | package types |
| 16 | |
| 17 | import ( |
| 18 | "reflect" |
| 19 | "sort" |
| 20 | "sync" |
| 21 | ) |
| 22 | |
| 23 | type Set interface { |
| 24 | Add(string) |
| 25 | Remove(string) |
| 26 | Contains(string) bool |
| 27 | Equals(Set) bool |
| 28 | Length() int |
| 29 | Values() []string |
| 30 | Copy() Set |
| 31 | Sub(Set) Set |
| 32 | } |
| 33 | |
| 34 | func NewUnsafeSet(values ...string) *unsafeSet { |
| 35 | set := &unsafeSet{make(map[string]struct{})} |
| 36 | for _, v := range values { |
| 37 | set.Add(v) |
| 38 | } |
| 39 | return set |
| 40 | } |
| 41 | |
| 42 | func NewThreadsafeSet(values ...string) *tsafeSet { |
| 43 | us := NewUnsafeSet(values...) |
| 44 | return &tsafeSet{us, sync.RWMutex{}} |
| 45 | } |
| 46 | |
| 47 | type unsafeSet struct { |
| 48 | d map[string]struct{} |
| 49 | } |
| 50 | |
| 51 | // Add adds a new value to the set (no-op if the value is already present) |
| 52 | func (us *unsafeSet) Add(value string) { |
| 53 | us.d[value] = struct{}{} |
| 54 | } |
| 55 | |
| 56 | // Remove removes the given value from the set |
| 57 | func (us *unsafeSet) Remove(value string) { |
| 58 | delete(us.d, value) |
| 59 | } |
| 60 | |
| 61 | // Contains returns whether the set contains the given value |
| 62 | func (us *unsafeSet) Contains(value string) (exists bool) { |
| 63 | _, exists = us.d[value] |
| 64 | return exists |
| 65 | } |
| 66 | |
| 67 | // ContainsAll returns whether the set contains all given values |
| 68 | func (us *unsafeSet) ContainsAll(values []string) bool { |
| 69 | for _, s := range values { |
| 70 | if !us.Contains(s) { |
| 71 | return false |
| 72 | } |
| 73 | } |
| 74 | return true |
| 75 | } |
| 76 | |
| 77 | // Equals returns whether the contents of two sets are identical |
| 78 | func (us *unsafeSet) Equals(other Set) bool { |
| 79 | v1 := sort.StringSlice(us.Values()) |
| 80 | v2 := sort.StringSlice(other.Values()) |
| 81 | v1.Sort() |
| 82 | v2.Sort() |
| 83 | return reflect.DeepEqual(v1, v2) |
| 84 | } |
| 85 | |
| 86 | // Length returns the number of elements in the set |
| 87 | func (us *unsafeSet) Length() int { |
| 88 | return len(us.d) |
| 89 | } |
| 90 | |
| 91 | // Values returns the values of the Set in an unspecified order. |
| 92 | func (us *unsafeSet) Values() (values []string) { |
| 93 | values = make([]string, 0) |
| 94 | for val := range us.d { |
| 95 | values = append(values, val) |
| 96 | } |
| 97 | return values |
| 98 | } |
| 99 | |
| 100 | // Copy creates a new Set containing the values of the first |
| 101 | func (us *unsafeSet) Copy() Set { |
| 102 | cp := NewUnsafeSet() |
| 103 | for val := range us.d { |
| 104 | cp.Add(val) |
| 105 | } |
| 106 | |
| 107 | return cp |
| 108 | } |
| 109 | |
| 110 | // Sub removes all elements in other from the set |
| 111 | func (us *unsafeSet) Sub(other Set) Set { |
| 112 | oValues := other.Values() |
| 113 | result := us.Copy().(*unsafeSet) |
| 114 | |
| 115 | for _, val := range oValues { |
| 116 | if _, ok := result.d[val]; !ok { |
| 117 | continue |
| 118 | } |
| 119 | delete(result.d, val) |
| 120 | } |
| 121 | |
| 122 | return result |
| 123 | } |
| 124 | |
| 125 | type tsafeSet struct { |
| 126 | us *unsafeSet |
| 127 | m sync.RWMutex |
| 128 | } |
| 129 | |
| 130 | func (ts *tsafeSet) Add(value string) { |
| 131 | ts.m.Lock() |
| 132 | defer ts.m.Unlock() |
| 133 | ts.us.Add(value) |
| 134 | } |
| 135 | |
| 136 | func (ts *tsafeSet) Remove(value string) { |
| 137 | ts.m.Lock() |
| 138 | defer ts.m.Unlock() |
| 139 | ts.us.Remove(value) |
| 140 | } |
| 141 | |
| 142 | func (ts *tsafeSet) Contains(value string) (exists bool) { |
| 143 | ts.m.RLock() |
| 144 | defer ts.m.RUnlock() |
| 145 | return ts.us.Contains(value) |
| 146 | } |
| 147 | |
| 148 | func (ts *tsafeSet) Equals(other Set) bool { |
| 149 | ts.m.RLock() |
| 150 | defer ts.m.RUnlock() |
Devmalya Paul | eb2e955 | 2019-08-27 19:42:00 -0400 | [diff] [blame] | 151 | |
| 152 | // If ts and other represent the same variable, avoid calling |
| 153 | // ts.us.Equals(other), to avoid double RLock bug |
| 154 | if _other, ok := other.(*tsafeSet); ok { |
| 155 | if _other == ts { |
| 156 | return true |
| 157 | } |
| 158 | } |
William Kurkian | ea86948 | 2019-04-09 15:16:11 -0400 | [diff] [blame] | 159 | return ts.us.Equals(other) |
| 160 | } |
| 161 | |
| 162 | func (ts *tsafeSet) Length() int { |
| 163 | ts.m.RLock() |
| 164 | defer ts.m.RUnlock() |
| 165 | return ts.us.Length() |
| 166 | } |
| 167 | |
| 168 | func (ts *tsafeSet) Values() (values []string) { |
| 169 | ts.m.RLock() |
| 170 | defer ts.m.RUnlock() |
| 171 | return ts.us.Values() |
| 172 | } |
| 173 | |
| 174 | func (ts *tsafeSet) Copy() Set { |
| 175 | ts.m.RLock() |
| 176 | defer ts.m.RUnlock() |
| 177 | usResult := ts.us.Copy().(*unsafeSet) |
| 178 | return &tsafeSet{usResult, sync.RWMutex{}} |
| 179 | } |
| 180 | |
| 181 | func (ts *tsafeSet) Sub(other Set) Set { |
| 182 | ts.m.RLock() |
| 183 | defer ts.m.RUnlock() |
Devmalya Paul | eb2e955 | 2019-08-27 19:42:00 -0400 | [diff] [blame] | 184 | |
| 185 | // If ts and other represent the same variable, avoid calling |
| 186 | // ts.us.Sub(other), to avoid double RLock bug |
| 187 | if _other, ok := other.(*tsafeSet); ok { |
| 188 | if _other == ts { |
| 189 | usResult := NewUnsafeSet() |
| 190 | return &tsafeSet{usResult, sync.RWMutex{}} |
| 191 | } |
| 192 | } |
William Kurkian | ea86948 | 2019-04-09 15:16:11 -0400 | [diff] [blame] | 193 | usResult := ts.us.Sub(other).(*unsafeSet) |
| 194 | return &tsafeSet{usResult, sync.RWMutex{}} |
| 195 | } |