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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package atomic_test
import (
"math/rand"
"runtime"
"strconv"
"sync"
"sync/atomic"
. "sync/atomic"
"testing"
)
func TestValue(t *testing.T) {
var v Value
if v.Load() != nil {
t.Fatal("initial Value is not nil")
}
v.Store(42)
x := v.Load()
if xx, ok := x.(int); !ok || xx != 42 {
t.Fatalf("wrong value: got %+v, want 42", x)
}
v.Store(84)
x = v.Load()
if xx, ok := x.(int); !ok || xx != 84 {
t.Fatalf("wrong value: got %+v, want 84", x)
}
}
func TestValueLarge(t *testing.T) {
var v Value
v.Store("foo")
x := v.Load()
if xx, ok := x.(string); !ok || xx != "foo" {
t.Fatalf("wrong value: got %+v, want foo", x)
}
v.Store("barbaz")
x = v.Load()
if xx, ok := x.(string); !ok || xx != "barbaz" {
t.Fatalf("wrong value: got %+v, want barbaz", x)
}
}
func TestValuePanic(t *testing.T) {
const nilErr = "sync/atomic: store of nil value into Value"
const badErr = "sync/atomic: store of inconsistently typed value into Value"
var v Value
func() {
defer func() {
err := recover()
if err != nilErr {
t.Fatalf("inconsistent store panic: got '%v', want '%v'", err, nilErr)
}
}()
v.Store(nil)
}()
v.Store(42)
func() {
defer func() {
err := recover()
if err != badErr {
t.Fatalf("inconsistent store panic: got '%v', want '%v'", err, badErr)
}
}()
v.Store("foo")
}()
func() {
defer func() {
err := recover()
if err != nilErr {
t.Fatalf("inconsistent store panic: got '%v', want '%v'", err, nilErr)
}
}()
v.Store(nil)
}()
}
func TestValueConcurrent(t *testing.T) {
tests := [][]any{
{uint16(0), ^uint16(0), uint16(1 + 2<<8), uint16(3 + 4<<8)},
{uint32(0), ^uint32(0), uint32(1 + 2<<16), uint32(3 + 4<<16)},
{uint64(0), ^uint64(0), uint64(1 + 2<<32), uint64(3 + 4<<32)},
{complex(0, 0), complex(1, 2), complex(3, 4), complex(5, 6)},
}
p := 4 * runtime.GOMAXPROCS(0)
N := int(1e5)
if testing.Short() {
p /= 2
N = 1e3
}
for _, test := range tests {
var v Value
done := make(chan bool, p)
for i := 0; i < p; i++ {
go func() {
r := rand.New(rand.NewSource(rand.Int63()))
expected := true
loop:
for j := 0; j < N; j++ {
x := test[r.Intn(len(test))]
v.Store(x)
x = v.Load()
for _, x1 := range test {
if x == x1 {
continue loop
}
}
t.Logf("loaded unexpected value %+v, want %+v", x, test)
expected = false
break
}
done <- expected
}()
}
for i := 0; i < p; i++ {
if !<-done {
t.FailNow()
}
}
}
}
func BenchmarkValueRead(b *testing.B) {
var v Value
v.Store(new(int))
b.RunParallel(func(pb *testing.PB) {
for pb.Next() {
x := v.Load().(*int)
if *x != 0 {
b.Fatalf("wrong value: got %v, want 0", *x)
}
}
})
}
var Value_SwapTests = []struct {
init any
new any
want any
err any
}{
{init: nil, new: nil, err: "sync/atomic: swap of nil value into Value"},
{init: nil, new: true, want: nil, err: nil},
{init: true, new: "", err: "sync/atomic: swap of inconsistently typed value into Value"},
{init: true, new: false, want: true, err: nil},
}
func TestValue_Swap(t *testing.T) {
for i, tt := range Value_SwapTests {
t.Run(strconv.Itoa(i), func(t *testing.T) {
var v Value
if tt.init != nil {
v.Store(tt.init)
}
defer func() {
err := recover()
switch {
case tt.err == nil && err != nil:
t.Errorf("should not panic, got %v", err)
case tt.err != nil && err == nil:
t.Errorf("should panic %v, got <nil>", tt.err)
}
}()
if got := v.Swap(tt.new); got != tt.want {
t.Errorf("got %v, want %v", got, tt.want)
}
if got := v.Load(); got != tt.new {
t.Errorf("got %v, want %v", got, tt.new)
}
})
}
}
func TestValueSwapConcurrent(t *testing.T) {
var v Value
var count uint64
var g sync.WaitGroup
var m, n uint64 = 10000, 10000
if testing.Short() {
m = 1000
n = 1000
}
for i := uint64(0); i < m*n; i += n {
i := i
g.Add(1)
go func() {
var c uint64
for new := i; new < i+n; new++ {
if old := v.Swap(new); old != nil {
c += old.(uint64)
}
}
atomic.AddUint64(&count, c)
g.Done()
}()
}
g.Wait()
if want, got := (m*n-1)*(m*n)/2, count+v.Load().(uint64); got != want {
t.Errorf("sum from 0 to %d was %d, want %v", m*n-1, got, want)
}
}
var heapA, heapB = struct{ uint }{0}, struct{ uint }{0}
var Value_CompareAndSwapTests = []struct {
init any
new any
old any
want bool
err any
}{
{init: nil, new: nil, old: nil, err: "sync/atomic: compare and swap of nil value into Value"},
{init: nil, new: true, old: "", err: "sync/atomic: compare and swap of inconsistently typed values into Value"},
{init: nil, new: true, old: true, want: false, err: nil},
{init: nil, new: true, old: nil, want: true, err: nil},
{init: true, new: "", err: "sync/atomic: compare and swap of inconsistently typed value into Value"},
{init: true, new: true, old: false, want: false, err: nil},
{init: true, new: true, old: true, want: true, err: nil},
{init: heapA, new: struct{ uint }{1}, old: heapB, want: true, err: nil},
}
func TestValue_CompareAndSwap(t *testing.T) {
for i, tt := range Value_CompareAndSwapTests {
t.Run(strconv.Itoa(i), func(t *testing.T) {
var v Value
if tt.init != nil {
v.Store(tt.init)
}
defer func() {
err := recover()
switch {
case tt.err == nil && err != nil:
t.Errorf("got %v, wanted no panic", err)
case tt.err != nil && err == nil:
t.Errorf("did not panic, want %v", tt.err)
}
}()
if got := v.CompareAndSwap(tt.old, tt.new); got != tt.want {
t.Errorf("got %v, want %v", got, tt.want)
}
})
}
}
func TestValueCompareAndSwapConcurrent(t *testing.T) {
var v Value
var w sync.WaitGroup
v.Store(0)
m, n := 1000, 100
if testing.Short() {
m = 100
n = 100
}
for i := 0; i < m; i++ {
i := i
w.Add(1)
go func() {
for j := i; j < m*n; runtime.Gosched() {
if v.CompareAndSwap(j, j+1) {
j += m
}
}
w.Done()
}()
}
w.Wait()
if stop := v.Load().(int); stop != m*n {
t.Errorf("did not get to %v, stopped at %v", m*n, stop)
}
}
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