Pretty printer for os.Waitmsg

R=rsc
APPROVED=rsc
DELTA=49  (49 added, 0 deleted, 0 changed)
OCL=31568
CL=31671

diff --git a/src/pkg/os/exec.go b/src/pkg/os/exec.go
index 9ae81c0d5a76a9314b3ead458674b2353dfeaad6..ceb52999b3a600225381764793a33a4fff4791f5 100644 (file)
--- a/src/pkg/os/exec.go
+++ b/src/pkg/os/exec.go
@@ -98,6 +98,55 @@ func Wait(pid int, options int) (w *Waitmsg, err Error) {
        return w, nil;
 }
 
+// Convert i to decimal string.
+func itod(i int) string {
+       if i == 0 {
+               return "0"
+       }
+
+       u := uint64(i);
+       if i < 0 {
+               u = -u;
+       }
+
+       // Assemble decimal in reverse order.
+       var b [32]byte;
+       bp := len(b);
+       for ; u > 0; u /= 10 {
+               bp--;
+               b[bp] = byte(u%10) + '0'
+       }
+
+       if i < 0 {
+               bp--;
+               b[bp] = '-'
+       }
+
+       return string(b[bp:len(b)])
+}
+
+func (w Waitmsg) String() string {
+       // TODO(austin) Use signal names when possible?
+       res := "";
+       switch {
+       case w.Exited():
+               res = "exit status " + itod(w.ExitStatus());
+       case w.Signaled():
+               res = "signal " + itod(w.Signal());
+       case w.Stopped():
+               res = "stop signal " + itod(w.StopSignal());
+               if w.StopSignal() == syscall.SIGTRAP && w.TrapCause() != 0 {
+                       res += " (trap " + itod(w.TrapCause()) + ")";
+               }
+       case w.Continued():
+               res = "continued";
+       }
+       if w.CoreDump() {
+               res += " (core dumped)"
+       }
+       return res;
+}
+
 // Getpid returns the process id of the caller.
 func Getpid() int {
        p, r2, e := syscall.Syscall(syscall.SYS_GETPID, 0, 0, 0);