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go/src/os/error.go
Ian Lance Taylor 187957d370 os: add deadline methods for File type
Add SetDeadline, SetReadDeadline, and SetWriteDeadline methods to os.File,
just as they exist today for the net package.

Fixes #22114

Change-Id: I4d390d739169b991175baba676010897dc8568fa
Reviewed-on: https://go-review.googlesource.com/71770
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Joe Tsai <thebrokentoaster@gmail.com>
2017-10-25 18:27:06 +00:00

105 lines
2.9 KiB
Go

// 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"
"internal/poll"
)
// Portable analogs of some common system call errors.
var (
ErrInvalid = errors.New("invalid argument") // methods on File will return this error when the receiver is nil
ErrPermission = errors.New("permission denied")
ErrExist = errors.New("file already exists")
ErrNotExist = errors.New("file does not exist")
ErrClosed = errors.New("file already closed")
ErrNoDeadline = poll.ErrNoDeadline
)
type timeout interface {
Timeout() bool
}
// 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() }
// Timeout reports whether this error represents a timeout.
func (e *PathError) Timeout() bool {
t, ok := e.Err.(timeout)
return ok && t.Timeout()
}
// 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() }
// Timeout reports whether this error represents a timeout.
func (e *SyscallError) Timeout() bool {
t, ok := e.Err.(timeout)
return ok && t.Timeout()
}
// 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)
}
// IsTimeout returns a boolean indicating whether the error is known
// to report that a timeout occurred.
func IsTimeout(err error) bool {
terr, ok := underlyingError(err).(timeout)
return ok && terr.Timeout()
}
// underlyingError returns the underlying error for known os error types.
func underlyingError(err error) error {
switch err := err.(type) {
case *PathError:
return err.Err
case *LinkError:
return err.Err
case *SyscallError:
return err.Err
}
return err
}