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 ...interface{}) { 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 } 43