98 lines
1.3 KiB
V
98 lines
1.3 KiB
V
import time
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import sync
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struct St {
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a int
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}
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fn f1(ch1 chan int, ch2 chan St, ch3 chan int, sem sync.Semaphore) {
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mut a := 5
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st := St{}
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select {
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a = <-ch3 {
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a = 0
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}
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b := <-ch2 {
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a = b.a
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}
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ch2 <- st {
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a = 2
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}
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> 300 * time.millisecond {
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a = 3
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}
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}
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assert a == 3
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sem.post()
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}
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fn f2(ch1 chan St, ch2 chan int, sem sync.Semaphore) {
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mut r := 23
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for i in 0 .. 2 {
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select {
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b := <- ch1 {
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r = b.a
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}
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ch2 <- r {
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r = 17
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}
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}
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if i == 0 {
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assert r == 17
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} else {
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assert r == 13
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}
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}
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sem.post()
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}
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fn test_select_blocks() {
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ch1 := chan int{cap: 1}
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ch2 := chan St{}
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ch3 := chan int{}
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sem := sync.new_semaphore()
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mut r := false
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t := select {
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b := <- ch1 {
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println(b)
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}
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else {
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// no channel ready
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r = true
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}
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}
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assert r == true
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assert t == true
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go f2(ch2, ch3, sem)
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n := <-ch3
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assert n == 23
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ch2 <- St{a: 13}
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sem.wait()
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stopwatch := time.new_stopwatch({})
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go f1(ch1, ch2, ch3, sem)
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sem.wait()
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elapsed_ms := f64(stopwatch.elapsed()) / time.millisecond
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assert elapsed_ms >= 295.0
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ch1.close()
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ch2.close()
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mut h := 7
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u := select {
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b := <- ch2 {
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h = 0
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}
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ch1 <- h {
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h = 1
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}
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else {
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h = 2
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}
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}
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// no branch should have run
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assert h == 7
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// since all channels are closed `select` should return `false`
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assert u == false
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}
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