1 files changed, 54 insertions, 0 deletions
diff --git a/src/os/error_plan9.go b/src/os/error_plan9.go
new file mode 100644
index 000000000..001cdfcf2
--- /dev/null
+++ b/src/os/error_plan9.go
@@ -0,0 +1,54 @@
+// Copyright 2011 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.
+
+package os
+
+func isExist(err error) bool {
+	switch pe := err.(type) {
+	case nil:
+		return false
+	case *PathError:
+		err = pe.Err
+	case *LinkError:
+		err = pe.Err
+	}
+	return contains(err.Error(), " exists")
+}
+
+func isNotExist(err error) bool {
+	switch pe := err.(type) {
+	case nil:
+		return false
+	case *PathError:
+		err = pe.Err
+	case *LinkError:
+		err = pe.Err
+	}
+	return contains(err.Error(), "does not exist") || contains(err.Error(), "not found") ||
+		contains(err.Error(), "has been removed") || contains(err.Error(), "no parent")
+}
+
+func isPermission(err error) bool {
+	switch pe := err.(type) {
+	case nil:
+		return false
+	case *PathError:
+		err = pe.Err
+	case *LinkError:
+		err = pe.Err
+	}
+	return contains(err.Error(), "permission denied")
+}
+
+// contains is a local version of strings.Contains. It knows len(sep) > 1.
+func contains(s, sep string) bool {
+	n := len(sep)
+	c := sep[0]
+	for i := 0; i+n <= len(s); i++ {
+		if s[i] == c && s[i:i+n] == sep {
+			return true
+		}
+	}
+	return false
+}