Source file src/pkg/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 ...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		return
    43	}