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// Copyright 2015 The etcd Authors
//
// 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.
package types
import (
"reflect"
"sort"
"sync"
)
type Set interface {
Add(string)
Remove(string)
Contains(string) bool
Equals(Set) bool
Length() int
Values() []string
Copy() Set
Sub(Set) Set
}
func NewUnsafeSet(values ...string) *unsafeSet {
set := &unsafeSet{make(map[string]struct{})}
for _, v := range values {
set.Add(v)
}
return set
}
func NewThreadsafeSet(values ...string) *tsafeSet {
us := NewUnsafeSet(values...)
return &tsafeSet{us, sync.RWMutex{}}
}
type unsafeSet struct {
d map[string]struct{}
}
// Add adds a new value to the set (no-op if the value is already present)
func (us *unsafeSet) Add(value string) {
us.d[value] = struct{}{}
}
// Remove removes the given value from the set
func (us *unsafeSet) Remove(value string) {
delete(us.d, value)
}
// Contains returns whether the set contains the given value
func (us *unsafeSet) Contains(value string) (exists bool) {
_, exists = us.d[value]
return exists
}
// ContainsAll returns whether the set contains all given values
func (us *unsafeSet) ContainsAll(values []string) bool {
for _, s := range values {
if !us.Contains(s) {
return false
}
}
return true
}
// Equals returns whether the contents of two sets are identical
func (us *unsafeSet) Equals(other Set) bool {
v1 := sort.StringSlice(us.Values())
v2 := sort.StringSlice(other.Values())
v1.Sort()
v2.Sort()
return reflect.DeepEqual(v1, v2)
}
// Length returns the number of elements in the set
func (us *unsafeSet) Length() int {
return len(us.d)
}
// Values returns the values of the Set in an unspecified order.
func (us *unsafeSet) Values() (values []string) {
values = make([]string, 0)
for val := range us.d {
values = append(values, val)
}
return values
}
// Copy creates a new Set containing the values of the first
func (us *unsafeSet) Copy() Set {
cp := NewUnsafeSet()
for val := range us.d {
cp.Add(val)
}
return cp
}
// Sub removes all elements in other from the set
func (us *unsafeSet) Sub(other Set) Set {
oValues := other.Values()
result := us.Copy().(*unsafeSet)
for _, val := range oValues {
if _, ok := result.d[val]; !ok {
continue
}
delete(result.d, val)
}
return result
}
type tsafeSet struct {
us *unsafeSet
m sync.RWMutex
}
func (ts *tsafeSet) Add(value string) {
ts.m.Lock()
defer ts.m.Unlock()
ts.us.Add(value)
}
func (ts *tsafeSet) Remove(value string) {
ts.m.Lock()
defer ts.m.Unlock()
ts.us.Remove(value)
}
func (ts *tsafeSet) Contains(value string) (exists bool) {
ts.m.RLock()
defer ts.m.RUnlock()
return ts.us.Contains(value)
}
func (ts *tsafeSet) Equals(other Set) bool {
ts.m.RLock()
defer ts.m.RUnlock()
// If ts and other represent the same variable, avoid calling
// ts.us.Equals(other), to avoid double RLock bug
if _other, ok := other.(*tsafeSet); ok {
if _other == ts {
return true
}
}
return ts.us.Equals(other)
}
func (ts *tsafeSet) Length() int {
ts.m.RLock()
defer ts.m.RUnlock()
return ts.us.Length()
}
func (ts *tsafeSet) Values() (values []string) {
ts.m.RLock()
defer ts.m.RUnlock()
return ts.us.Values()
}
func (ts *tsafeSet) Copy() Set {
ts.m.RLock()
defer ts.m.RUnlock()
usResult := ts.us.Copy().(*unsafeSet)
return &tsafeSet{usResult, sync.RWMutex{}}
}
func (ts *tsafeSet) Sub(other Set) Set {
ts.m.RLock()
defer ts.m.RUnlock()
// If ts and other represent the same variable, avoid calling
// ts.us.Sub(other), to avoid double RLock bug
if _other, ok := other.(*tsafeSet); ok {
if _other == ts {
usResult := NewUnsafeSet()
return &tsafeSet{usResult, sync.RWMutex{}}
}
}
usResult := ts.us.Sub(other).(*unsafeSet)
return &tsafeSet{usResult, sync.RWMutex{}}
}
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