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  }
    43
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