Add 'lib/protocol/' from commit 'f91191218b192ace841c878f161832d19c09145a'

git-subtree-dir: lib/protocol
git-subtree-mainline: 5ecb8bdd8a
git-subtree-split: f91191218b

lib/protocol/errors.go

@@ -0,0 +1,51 @@
+// Copyright (C) 2014 The Protocol Authors.
+
+package protocol
+
+import (
+	"errors"
+)
+
+const (
+	ecNoError int32 = iota
+	ecGeneric
+	ecNoSuchFile
+	ecInvalid
+)
+
+var (
+	ErrNoError    error = nil
+	ErrGeneric          = errors.New("generic error")
+	ErrNoSuchFile       = errors.New("no such file")
+	ErrInvalid          = errors.New("file is invalid")
+)
+
+var lookupError = map[int32]error{
+	ecNoError:    ErrNoError,
+	ecGeneric:    ErrGeneric,
+	ecNoSuchFile: ErrNoSuchFile,
+	ecInvalid:    ErrInvalid,
+}
+
+var lookupCode = map[error]int32{
+	ErrNoError:    ecNoError,
+	ErrGeneric:    ecGeneric,
+	ErrNoSuchFile: ecNoSuchFile,
+	ErrInvalid:    ecInvalid,
+}
+
+func codeToError(errcode int32) error {
+	err, ok := lookupError[errcode]
+	if !ok {
+		return ErrGeneric
+	}
+	return err
+}
+
+func errorToCode(err error) int32 {
+	code, ok := lookupCode[err]
+	if !ok {
+		return ecGeneric
+	}
+	return code
+}