Go requires a separated folder for v2+ to keep the
compatibility for tools that are not version-aware.
https://go.dev/blog/v2-go-modules
This commit is contained in:
Tevin Zhang 2021-09-25 13:55:34 +08:00
parent 4c6c31b893
commit 7170548ea7
4 changed files with 376 additions and 0 deletions

21
v2/LICENSE Normal file
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The MIT License (MIT)
Copyright (c) 2016 Tevin Zhang
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

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v2/bool.go Normal file
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// Package abool provides atomic Boolean type for cleaner code and
// better performance.
package abool
import (
"encoding/json"
"sync/atomic"
)
// New creates an AtomicBool with default set to false.
func New() *AtomicBool {
return new(AtomicBool)
}
// NewBool creates an AtomicBool with given default value.
func NewBool(ok bool) *AtomicBool {
ab := New()
if ok {
ab.Set()
}
return ab
}
// AtomicBool is an atomic Boolean.
// Its methods are all atomic, thus safe to be called by multiple goroutines simultaneously.
// Note: When embedding into a struct one should always use *AtomicBool to avoid copy.
type AtomicBool int32
// Set sets the Boolean to true.
func (ab *AtomicBool) Set() {
atomic.StoreInt32((*int32)(ab), 1)
}
// UnSet sets the Boolean to false.
func (ab *AtomicBool) UnSet() {
atomic.StoreInt32((*int32)(ab), 0)
}
// IsSet returns whether the Boolean is true.
func (ab *AtomicBool) IsSet() bool {
return atomic.LoadInt32((*int32)(ab)) == 1
}
// IsNotSet returns whether the Boolean is false.
func (ab *AtomicBool) IsNotSet() bool {
return !ab.IsSet()
}
// SetTo sets the boolean with given Boolean.
func (ab *AtomicBool) SetTo(yes bool) {
if yes {
atomic.StoreInt32((*int32)(ab), 1)
} else {
atomic.StoreInt32((*int32)(ab), 0)
}
}
// SetToIf sets the Boolean to new only if the Boolean matches the old.
// Returns whether the set was done.
func (ab *AtomicBool) SetToIf(old, new bool) (set bool) {
var o, n int32
if old {
o = 1
}
if new {
n = 1
}
return atomic.CompareAndSwapInt32((*int32)(ab), o, n)
}
// MarshalJSON behaves the same as if the AtomicBool is a builtin.bool.
// NOTE: There's no lock during the process, usually it shouldn't be called with other methods in parallel.
func (ab *AtomicBool) MarshalJSON() ([]byte, error) {
return json.Marshal(ab.IsSet())
}
// UnmarshalJSON behaves the same as if the AtomicBool is a builtin.bool.
// NOTE: There's no lock during the process, usually it shouldn't be called with other methods in parallel.
func (ab *AtomicBool) UnmarshalJSON(b []byte) error {
var v bool
err := json.Unmarshal(b, &v)
if err == nil {
ab.SetTo(v)
}
return err
}

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v2/bool_test.go Normal file
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package abool
import (
"encoding/json"
"sync"
"sync/atomic"
"testing"
)
func TestDefaultValue(t *testing.T) {
t.Parallel()
v := New()
if v.IsSet() {
t.Fatal("Empty value of AtomicBool should be false")
}
v = NewBool(true)
if !v.IsSet() {
t.Fatal("NewValue(true) should be true")
}
v = NewBool(false)
if v.IsSet() {
t.Fatal("NewValue(false) should be false")
}
}
func TestIsNotSet(t *testing.T) {
t.Parallel()
v := New()
if v.IsSet() == v.IsNotSet() {
t.Fatal("AtomicBool.IsNotSet() should be the opposite of IsSet()")
}
}
func TestSetUnSet(t *testing.T) {
t.Parallel()
v := New()
v.Set()
if !v.IsSet() {
t.Fatal("AtomicBool.Set() failed")
}
v.UnSet()
if v.IsSet() {
t.Fatal("AtomicBool.UnSet() failed")
}
}
func TestSetTo(t *testing.T) {
t.Parallel()
v := New()
v.SetTo(true)
if !v.IsSet() {
t.Fatal("AtomicBool.SetTo(true) failed")
}
v.SetTo(false)
if v.IsSet() {
t.Fatal("AtomicBool.SetTo(false) failed")
}
if set := v.SetToIf(true, false); set || v.IsSet() {
t.Fatal("AtomicBool.SetTo(true, false) failed")
}
if set := v.SetToIf(false, true); !set || !v.IsSet() {
t.Fatal("AtomicBool.SetTo(false, true) failed")
}
}
func TestRace(t *testing.T) {
repeat := 10000
var wg sync.WaitGroup
wg.Add(repeat * 3)
v := New()
// Writer
go func() {
for i := 0; i < repeat; i++ {
v.Set()
wg.Done()
}
}()
// Reader
go func() {
for i := 0; i < repeat; i++ {
v.IsSet()
wg.Done()
}
}()
// Writer
go func() {
for i := 0; i < repeat; i++ {
v.UnSet()
wg.Done()
}
}()
wg.Wait()
}
func TestJSONCompatibleWithBuiltinBool(t *testing.T) {
for _, value := range []bool{true, false} {
// Test bool -> bytes -> AtomicBool
// act 1. bool -> bytes
buf, err := json.Marshal(value)
if err != nil {
t.Fatalf("json.Marshal(%t) failed: %s", value, err)
}
// act 2. bytes -> AtomicBool
//
// Try to unmarshall the JSON byte slice
// of a normal boolean into an AtomicBool
//
// Create an AtomicBool with the oppsite default to ensure the unmarshal process did the work
ab := NewBool(!value)
err = json.Unmarshal(buf, ab)
if err != nil {
t.Fatalf(`json.Unmarshal("%s", %T) failed: %s`, buf, ab, err)
}
// assert
if ab.IsSet() != value {
t.Fatalf("Expected AtomicBool to represent %t but actual value was %t", value, ab.IsSet())
}
// Test AtomicBool -> bytes -> bool
// act 3. AtomicBool -> bytes
buf, err = json.Marshal(ab)
if err != nil {
t.Fatalf("json.Marshal(%T) failed: %s", ab, err)
}
// using the opposite value for the same reason as the former case
b := ab.IsNotSet()
// act 4. bytes -> bool
err = json.Unmarshal(buf, &b)
if err != nil {
t.Fatalf(`json.Unmarshal("%s", %T) failed: %s`, buf, &b, err)
}
// assert
if b != ab.IsSet() {
t.Fatalf(`json.Unmarshal("%s", %T) didn't work, expected %t, got %t`, buf, ab, ab.IsSet(), b)
}
}
}
func TestUnmarshalJSONErrorNoWrite(t *testing.T) {
for _, val := range []bool{true, false} {
ab := NewBool(val)
oldVal := ab.IsSet()
buf := []byte("invalid-json")
err := json.Unmarshal(buf, ab)
if err == nil {
t.Fatalf(`Error expected from json.Unmarshal("%s", %T)`, buf, ab)
}
if oldVal != ab.IsSet() {
t.Fatal("Failed json.Unmarshal modified the value of AtomicBool which is not expected")
}
}
}
func ExampleAtomicBool() {
cond := New() // default to false
any := true
old := any
new := !any
cond.Set() // Sets to true
cond.IsSet() // Returns true
cond.UnSet() // Sets to false
cond.IsNotSet() // Returns true
cond.SetTo(any) // Sets to whatever you want
cond.SetToIf(new, old) // Sets to `new` only if the Boolean matches the `old`, returns whether succeeded
}
// Benchmark Read
func BenchmarkMutexRead(b *testing.B) {
var m sync.RWMutex
var v bool
b.ResetTimer()
for i := 0; i < b.N; i++ {
m.RLock()
_ = v
m.RUnlock()
}
}
func BenchmarkAtomicValueRead(b *testing.B) {
var v atomic.Value
b.ResetTimer()
for i := 0; i < b.N; i++ {
_ = v.Load() != nil
}
}
func BenchmarkAtomicBoolRead(b *testing.B) {
v := New()
b.ResetTimer()
for i := 0; i < b.N; i++ {
_ = v.IsSet()
}
}
// Benchmark Write
func BenchmarkMutexWrite(b *testing.B) {
var m sync.RWMutex
var v bool
b.ResetTimer()
for i := 0; i < b.N; i++ {
m.RLock()
v = true
m.RUnlock()
}
b.StopTimer()
_ = v
}
func BenchmarkAtomicValueWrite(b *testing.B) {
var v atomic.Value
b.ResetTimer()
for i := 0; i < b.N; i++ {
v.Store(true)
}
}
func BenchmarkAtomicBoolWrite(b *testing.B) {
v := New()
b.ResetTimer()
for i := 0; i < b.N; i++ {
v.Set()
}
}
// Benchmark CAS
func BenchmarkMutexCAS(b *testing.B) {
var m sync.RWMutex
var v bool
b.ResetTimer()
for i := 0; i < b.N; i++ {
m.Lock()
if !v {
v = true
}
m.Unlock()
}
}
func BenchmarkAtomicBoolCAS(b *testing.B) {
v := New()
b.ResetTimer()
for i := 0; i < b.N; i++ {
v.SetToIf(false, true)
}
}

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v2/go.mod Normal file
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module github.com/tevino/abool/v2
go 1.17