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-rw-r--r--gcc-4.9/gcc/testsuite/go.test/test/chan/select3.go224
1 files changed, 224 insertions, 0 deletions
diff --git a/gcc-4.9/gcc/testsuite/go.test/test/chan/select3.go b/gcc-4.9/gcc/testsuite/go.test/test/chan/select3.go
new file mode 100644
index 000000000..847d8ed37
--- /dev/null
+++ b/gcc-4.9/gcc/testsuite/go.test/test/chan/select3.go
@@ -0,0 +1,224 @@
+// run
+
+// 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.
+
+// Test 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 blocks
+ testBlock(always, func() {
+ nilch <- 7
+ })
+ testBlock(always, func() {
+ <-nilch
+ })
+
+ // sending/receiving from a nil channel inside a select is never selected
+ 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 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")
+ }
+ if x, ok := <-closedch; x != 0 || ok {
+ println("closedch:", x, ok)
+ panic("expected 0, false from closed channel")
+ }
+ }
+ })
+
+ // sending to a closed channel panics.
+ testPanic(always, func() {
+ 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 behave like ordinary operations
+ testBlock(never, func() {
+ select {
+ case <-closedch:
+ }
+ })
+ testBlock(never, func() {
+ select {
+ case x := (<-closedch):
+ _ = x
+ }
+ })
+ testBlock(never, func() {
+ select {
+ case x, ok := (<-closedch):
+ _, _ = x, ok
+ }
+ })
+ testPanic(always, func() {
+ select {
+ case closedch <- 7:
+ }
+ })
+
+ // select should not get confused if it sees itself
+ testBlock(always, func() {
+ c := make(chan int)
+ select {
+ case c <- 1:
+ case <-c:
+ }
+ })
+}