libgo: update to go1.9

    
    Reviewed-on: https://go-review.googlesource.com/63753

From-SVN: r252767

1 files changed, 23 insertions, 2 deletions

diff --git a/libgo/go/cmd/internal/browser/browser.go b/libgo/go/cmd/internal/browser/browser.go
index 897086f4717..6867c85d232 100644
--- a/libgo/go/cmd/internal/browser/browser.go
+++ b/libgo/go/cmd/internal/browser/browser.go
@@ -9,6 +9,7 @@ import (
 	"os"
 	"os/exec"
 	"runtime"
+	"time"
 )
 
 // Commands returns a list of possible commands to use to open a url.
@@ -23,7 +24,10 @@ func Commands() [][]string {
 	case "windows":
 		cmds = append(cmds, []string{"cmd", "/c", "start"})
 	default:
-		cmds = append(cmds, []string{"xdg-open"})
+		if os.Getenv("DISPLAY") != "" {
+			// xdg-open is only for use in a desktop environment.
+			cmds = append(cmds, []string{"xdg-open"})
+		}
 	}
 	cmds = append(cmds,
 		[]string{"chrome"},
@@ -38,9 +42,26 @@ func Commands() [][]string {
 func Open(url string) bool {
 	for _, args := range Commands() {
 		cmd := exec.Command(args[0], append(args[1:], url)...)
-		if cmd.Start() == nil {
+		if cmd.Start() == nil && appearsSuccessful(cmd, 3*time.Second) {
 			return true
 		}
 	}
 	return false
 }
+
+// appearsSuccessful reports whether the command appears to have run successfully.
+// If the command runs longer than the timeout, it's deemed successful.
+// If the command runs within the timeout, it's deemed successful if it exited cleanly.
+func appearsSuccessful(cmd *exec.Cmd, timeout time.Duration) bool {
+	errc := make(chan error, 1)
+	go func() {
+		errc <- cmd.Wait()
+	}()
+
+	select {
+	case <-time.After(timeout):
+		return true
+	case err := <-errc:
+		return err == nil
+	}
+}