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package errors
import "unsafe"
func Join(errs ...error) error {
n := 0
for _, err := range errs {
if err != nil {
n++
}
}
if n == 0 {
return nil
}
e := &joinError{
errs: make([]error, 0, n),
}
for _, err := range errs {
if err != nil {
e.errs = append(e.errs, err)
}
}
return e
}
type joinError struct {
errs []error
}
func (e *joinError) Error() string {
// Since Join returns nil if every value in errs is nil,
// e.errs cannot be empty.
if len(e.errs) == 1 {
return e.errs[0].Error()
}
b := []byte(e.errs[0].Error())
for _, err := range e.errs[1:] {
b = append(b, ':', ' ')
b = append(b, err.Error()...)
}
// At this point, b has at least one byte '\n'.
return unsafe.String(&b[0], len(b))
}
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