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authorupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
committerupstream source tree <ports@midipix.org>2015-03-15 20:14:05 -0400
commit554fd8c5195424bdbcabf5de30fdc183aba391bd (patch)
tree976dc5ab7fddf506dadce60ae936f43f58787092 /gcc/testsuite/go.test/test/chan/select3.go
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Diffstat (limited to 'gcc/testsuite/go.test/test/chan/select3.go')
-rw-r--r--gcc/testsuite/go.test/test/chan/select3.go203
1 files changed, 203 insertions, 0 deletions
diff --git a/gcc/testsuite/go.test/test/chan/select3.go b/gcc/testsuite/go.test/test/chan/select3.go
new file mode 100644
index 000000000..a1a2ef50b
--- /dev/null
+++ b/gcc/testsuite/go.test/test/chan/select3.go
@@ -0,0 +1,203 @@
+// $G $D/$F.go && $L $F.$A && ./$A.out
+
+// Copyright 2010 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.
+
+// Tests verifying the semantics of the select statement
+// for basic empty/non-empty cases.
+
+package main
+
+import "time"
+
+const always = "function did not"
+const never = "function did"
+
+
+func unreachable() {
+ panic("control flow shouldn't reach here")
+}
+
+
+// Calls f and verifies that f always/never panics depending on signal.
+func testPanic(signal string, f func()) {
+ defer func() {
+ s := never
+ if recover() != nil {
+ s = always // f panicked
+ }
+ if s != signal {
+ panic(signal + " panic")
+ }
+ }()
+ f()
+}
+
+
+// Calls f and empirically verifies that f always/never blocks depending on signal.
+func testBlock(signal string, f func()) {
+ c := make(chan string)
+ go func() {
+ f()
+ c <- never // f didn't block
+ }()
+ go func() {
+ time.Sleep(1e8) // 0.1s seems plenty long
+ c <- always // f blocked always
+ }()
+ if <-c != signal {
+ panic(signal + " block")
+ }
+}
+
+
+func main() {
+ const async = 1 // asynchronous channels
+ var nilch chan int
+ closedch := make(chan int)
+ close(closedch)
+
+ // sending/receiving from a nil channel outside a select panics
+ testPanic(always, func() {
+ nilch <- 7
+ })
+ testPanic(always, func() {
+ <-nilch
+ })
+
+ // sending/receiving from a nil channel inside a select never panics
+ testPanic(never, func() {
+ select {
+ case nilch <- 7:
+ unreachable()
+ default:
+ }
+ })
+ testPanic(never, func() {
+ select {
+ case <-nilch:
+ unreachable()
+ default:
+ }
+ })
+
+ // sending to an async channel with free buffer space never blocks
+ testBlock(never, func() {
+ ch := make(chan int, async)
+ ch <- 7
+ })
+
+ // receiving (a small number of times) from a closed channel never blocks
+ testBlock(never, func() {
+ for i := 0; i < 10; i++ {
+ if <-closedch != 0 {
+ panic("expected zero value when reading from closed channel")
+ }
+ }
+ })
+
+ // sending (a small number of times) to a closed channel is not specified
+ // but the current implementation doesn't block: test that different
+ // implementations behave the same
+ testBlock(never, func() {
+ for i := 0; i < 10; i++ {
+ closedch <- 7
+ }
+ })
+
+ // receiving from a non-ready channel always blocks
+ testBlock(always, func() {
+ ch := make(chan int)
+ <-ch
+ })
+
+ // empty selects always block
+ testBlock(always, func() {
+ select {
+ }
+ })
+
+ // selects with only nil channels always block
+ testBlock(always, func() {
+ select {
+ case <-nilch:
+ unreachable()
+ }
+ })
+ testBlock(always, func() {
+ select {
+ case nilch <- 7:
+ unreachable()
+ }
+ })
+ testBlock(always, func() {
+ select {
+ case <-nilch:
+ unreachable()
+ case nilch <- 7:
+ unreachable()
+ }
+ })
+
+ // selects with non-ready non-nil channels always block
+ testBlock(always, func() {
+ ch := make(chan int)
+ select {
+ case <-ch:
+ unreachable()
+ }
+ })
+
+ // selects with default cases don't block
+ testBlock(never, func() {
+ select {
+ default:
+ }
+ })
+ testBlock(never, func() {
+ select {
+ case <-nilch:
+ unreachable()
+ default:
+ }
+ })
+ testBlock(never, func() {
+ select {
+ case nilch <- 7:
+ unreachable()
+ default:
+ }
+ })
+
+ // selects with ready channels don't block
+ testBlock(never, func() {
+ ch := make(chan int, async)
+ select {
+ case ch <- 7:
+ default:
+ unreachable()
+ }
+ })
+ testBlock(never, func() {
+ ch := make(chan int, async)
+ ch <- 7
+ select {
+ case <-ch:
+ default:
+ unreachable()
+ }
+ })
+
+ // selects with closed channels don't block
+ testBlock(never, func() {
+ select {
+ case <-closedch:
+ }
+ })
+ testBlock(never, func() {
+ select {
+ case closedch <- 7:
+ }
+ })
+}