1 files changed, 65 insertions, 0 deletions
diff --git a/src/os/error.go b/src/os/error.go
new file mode 100644
index 000000000..8810e6930
--- /dev/null
+++ b/src/os/error.go
@@ -0,0 +1,65 @@
+// Copyright 2009 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
+
+import (
+	"errors"
+)
+
+// Portable analogs of some common system call errors.
+var (
+	ErrInvalid    = errors.New("invalid argument")
+	ErrPermission = errors.New("permission denied")
+	ErrExist      = errors.New("file already exists")
+	ErrNotExist   = errors.New("file does not exist")
+)
+
+// PathError records an error and the operation and file path that caused it.
+type PathError struct {
+	Op   string
+	Path string
+	Err  error
+}
+
+func (e *PathError) Error() string { return e.Op + " " + e.Path + ": " + e.Err.Error() }
+
+// SyscallError records an error from a specific system call.
+type SyscallError struct {
+	Syscall string
+	Err     error
+}
+
+func (e *SyscallError) Error() string { return e.Syscall + ": " + e.Err.Error() }
+
+// NewSyscallError returns, as an error, a new SyscallError
+// with the given system call name and error details.
+// As a convenience, if err is nil, NewSyscallError returns nil.
+func NewSyscallError(syscall string, err error) error {
+	if err == nil {
+		return nil
+	}
+	return &SyscallError{syscall, err}
+}
+
+// IsExist returns a boolean indicating whether the error is known to report
+// that a file or directory already exists. It is satisfied by ErrExist as
+// well as some syscall errors.
+func IsExist(err error) bool {
+	return isExist(err)
+}
+
+// IsNotExist returns a boolean indicating whether the error is known to
+// report that a file or directory does not exist. It is satisfied by
+// ErrNotExist as well as some syscall errors.
+func IsNotExist(err error) bool {
+	return isNotExist(err)
+}
+
+// IsPermission returns a boolean indicating whether the error is known to
+// report that permission is denied. It is satisfied by ErrPermission as well
+// as some syscall errors.
+func IsPermission(err error) bool {
+	return isPermission(err)
+}