libgo/go/encoding/gob/error.go

   1 // Copyright 2009 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 package gob
   6
   7 import "fmt"
   8
   9 // Errors in decoding and encoding are handled using panic and recover.
  10 // Panics caused by user error (that is, everything except run-time panics
  11 // such as "index out of bounds" errors) do not leave the file that caused
  12 // them, but are instead turned into plain error returns. Encoding and
  13 // decoding functions and methods that do not return an error either use
  14 // panic to report an error or are guaranteed error-free.
  15
  16 // A gobError is used to distinguish errors (panics) generated in this package.
  17 type gobError struct {
  18         err error
  19 }
  20
  21 // errorf is like error_ but takes Printf-style arguments to construct an error.
  22 // It always prefixes the message with "gob: ".
  23 func errorf(format string, args ...any) {
  24         error_(fmt.Errorf("gob: "+format, args...))
  25 }
  26
  27 // error wraps the argument error and uses it as the argument to panic.
  28 func error_(err error) {
  29         panic(gobError{err})
  30 }
  31
  32 // catchError is meant to be used as a deferred function to turn a panic(gobError) into a
  33 // plain error. It overwrites the error return of the function that deferred its call.
  34 func catchError(err *error) {
  35         if e := recover(); e != nil {
  36                 ge, ok := e.(gobError)
  37                 if !ok {
  38                         panic(e)
  39                 }
  40                 *err = ge.err
  41         }
  42 }