2 files changed, 56 insertions, 4 deletions

diff --git a/src/pkg/io/ioutil/tempfile.go b/src/pkg/io/ioutil/tempfile.go
index 114eca2b5..62f8849c0 100644
--- a/src/pkg/io/ioutil/tempfile.go
+++ b/src/pkg/io/ioutil/tempfile.go
@@ -6,6 +6,7 @@ package ioutil
 
 import (
 	"os"
+	"path/filepath"
 	"strconv"
 )
 
@@ -46,7 +47,7 @@ func TempFile(dir, prefix string) (f *os.File, err os.Error) {
 
 	nconflict := 0
 	for i := 0; i < 10000; i++ {
-		name := dir + "/" + prefix + nextSuffix()
+		name := filepath.Join(dir, prefix+nextSuffix())
 		f, err = os.Open(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0600)
 		if pe, ok := err.(*os.PathError); ok && pe.Error == os.EEXIST {
 			if nconflict++; nconflict > 10 {
@@ -58,3 +59,33 @@ func TempFile(dir, prefix string) (f *os.File, err os.Error) {
 	}
 	return
 }
+
+// TempDir creates a new temporary directory in the directory dir
+// with a name beginning with prefix and returns the path of the
+// new directory.  If dir is the empty string, TempDir uses the
+// default directory for temporary files (see os.TempDir).
+// Multiple programs calling TempDir simultaneously
+// will not choose the same directory.  It is the caller's responsibility
+// to remove the directory when no longer needed.
+func TempDir(dir, prefix string) (name string, err os.Error) {
+	if dir == "" {
+		dir = os.TempDir()
+	}
+
+	nconflict := 0
+	for i := 0; i < 10000; i++ {
+		try := filepath.Join(dir, prefix+nextSuffix())
+		err = os.Mkdir(try, 0700)
+		if pe, ok := err.(*os.PathError); ok && pe.Error == os.EEXIST {
+			if nconflict++; nconflict > 10 {
+				rand = reseed()
+			}
+			continue
+		}
+		if err == nil {
+			name = try
+		}
+		break
+	}
+	return
+}
diff --git a/src/pkg/io/ioutil/tempfile_test.go b/src/pkg/io/ioutil/tempfile_test.go
index d949a86cf..80c62f672 100644
--- a/src/pkg/io/ioutil/tempfile_test.go
+++ b/src/pkg/io/ioutil/tempfile_test.go
@@ -7,6 +7,7 @@ package ioutil_test
 import (
 	. "io/ioutil"
 	"os"
+	"path/filepath"
 	"regexp"
 	"testing"
 )
@@ -23,11 +24,31 @@ func TestTempFile(t *testing.T) {
 		t.Errorf("TempFile(dir, `ioutil_test`) = %v, %v", f, err)
 	}
 	if f != nil {
-		re := regexp.MustCompile("^" + regexp.QuoteMeta(dir) + "/ioutil_test[0-9]+$")
+		f.Close()
+		os.Remove(f.Name())
+		re := regexp.MustCompile("^" + regexp.QuoteMeta(filepath.Join(dir, "ioutil_test")) + "[0-9]+$")
 		if !re.MatchString(f.Name()) {
 			t.Errorf("TempFile(`"+dir+"`, `ioutil_test`) created bad name %s", f.Name())
 		}
-		os.Remove(f.Name())
 	}
-	f.Close()
+}
+
+func TestTempDir(t *testing.T) {
+	name, err := TempDir("/_not_exists_", "foo")
+	if name != "" || err == nil {
+		t.Errorf("TempDir(`/_not_exists_`, `foo`) = %v, %v", name, err)
+	}
+
+	dir := os.TempDir()
+	name, err = TempDir(dir, "ioutil_test")
+	if name == "" || err != nil {
+		t.Errorf("TempDir(dir, `ioutil_test`) = %v, %v", name, err)
+	}
+	if name != "" {
+		os.Remove(name)
+		re := regexp.MustCompile("^" + regexp.QuoteMeta(filepath.Join(dir, "ioutil_test")) + "[0-9]+$")
+		if !re.MatchString(name) {
+			t.Errorf("TempDir(`"+dir+"`, `ioutil_test`) created bad name %s", name)
+		}
+	}
 }