mirror of
https://github.com/go-gitea/gitea.git
synced 2024-12-15 17:49:20 +08:00
107 lines
3.0 KiB
Go
Vendored
107 lines
3.0 KiB
Go
Vendored
// Copyright 2018 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 xerrors
|
|
|
|
import (
|
|
"reflect"
|
|
)
|
|
|
|
// A Wrapper provides context around another error.
|
|
type Wrapper interface {
|
|
// Unwrap returns the next error in the error chain.
|
|
// If there is no next error, Unwrap returns nil.
|
|
Unwrap() error
|
|
}
|
|
|
|
// Opaque returns an error with the same error formatting as err
|
|
// but that does not match err and cannot be unwrapped.
|
|
func Opaque(err error) error {
|
|
return noWrapper{err}
|
|
}
|
|
|
|
type noWrapper struct {
|
|
error
|
|
}
|
|
|
|
func (e noWrapper) FormatError(p Printer) (next error) {
|
|
if f, ok := e.error.(Formatter); ok {
|
|
return f.FormatError(p)
|
|
}
|
|
p.Print(e.error)
|
|
return nil
|
|
}
|
|
|
|
// Unwrap returns the result of calling the Unwrap method on err, if err implements
|
|
// Unwrap. Otherwise, Unwrap returns nil.
|
|
func Unwrap(err error) error {
|
|
u, ok := err.(Wrapper)
|
|
if !ok {
|
|
return nil
|
|
}
|
|
return u.Unwrap()
|
|
}
|
|
|
|
// Is reports whether any error in err's chain matches target.
|
|
//
|
|
// An error is considered to match a target if it is equal to that target or if
|
|
// it implements a method Is(error) bool such that Is(target) returns true.
|
|
func Is(err, target error) bool {
|
|
if target == nil {
|
|
return err == target
|
|
}
|
|
|
|
isComparable := reflect.TypeOf(target).Comparable()
|
|
for {
|
|
if isComparable && err == target {
|
|
return true
|
|
}
|
|
if x, ok := err.(interface{ Is(error) bool }); ok && x.Is(target) {
|
|
return true
|
|
}
|
|
// TODO: consider supporing target.Is(err). This would allow
|
|
// user-definable predicates, but also may allow for coping with sloppy
|
|
// APIs, thereby making it easier to get away with them.
|
|
if err = Unwrap(err); err == nil {
|
|
return false
|
|
}
|
|
}
|
|
}
|
|
|
|
// As finds the first error in err's chain that matches the type to which target
|
|
// points, and if so, sets the target to its value and returns true. An error
|
|
// matches a type if it is assignable to the target type, or if it has a method
|
|
// As(interface{}) bool such that As(target) returns true. As will panic if target
|
|
// is not a non-nil pointer to a type which implements error or is of interface type.
|
|
//
|
|
// The As method should set the target to its value and return true if err
|
|
// matches the type to which target points.
|
|
func As(err error, target interface{}) bool {
|
|
if target == nil {
|
|
panic("errors: target cannot be nil")
|
|
}
|
|
val := reflect.ValueOf(target)
|
|
typ := val.Type()
|
|
if typ.Kind() != reflect.Ptr || val.IsNil() {
|
|
panic("errors: target must be a non-nil pointer")
|
|
}
|
|
if e := typ.Elem(); e.Kind() != reflect.Interface && !e.Implements(errorType) {
|
|
panic("errors: *target must be interface or implement error")
|
|
}
|
|
targetType := typ.Elem()
|
|
for err != nil {
|
|
if reflect.TypeOf(err).AssignableTo(targetType) {
|
|
val.Elem().Set(reflect.ValueOf(err))
|
|
return true
|
|
}
|
|
if x, ok := err.(interface{ As(interface{}) bool }); ok && x.As(target) {
|
|
return true
|
|
}
|
|
err = Unwrap(err)
|
|
}
|
|
return false
|
|
}
|
|
|
|
var errorType = reflect.TypeOf((*error)(nil)).Elem()
|