124 lines
2.6 KiB
Go
124 lines
2.6 KiB
Go
// Copyright (C) MongoDB, Inc. 2017-present.
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//
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// Licensed under the Apache License, Version 2.0 (the "License"); you may
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// not use this file except in compliance with the License. You may obtain
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// a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
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package internal
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import (
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"fmt"
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)
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// WrappedError represents an error that contains another error.
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type WrappedError interface {
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// Message gets the basic message of the error.
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Message() string
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// Inner gets the inner error if one exists.
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Inner() error
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}
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// RolledUpErrorMessage gets a flattened error message.
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func RolledUpErrorMessage(err error) string {
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if wrappedErr, ok := err.(WrappedError); ok {
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inner := wrappedErr.Inner()
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if inner != nil {
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return fmt.Sprintf("%s: %s", wrappedErr.Message(), RolledUpErrorMessage(inner))
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}
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return wrappedErr.Message()
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}
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return err.Error()
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}
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// UnwrapError attempts to unwrap the error down to its root cause.
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func UnwrapError(err error) error {
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switch tErr := err.(type) {
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case WrappedError:
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return UnwrapError(tErr.Inner())
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case *multiError:
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return UnwrapError(tErr.errors[0])
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}
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return err
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}
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// WrapError wraps an error with a message.
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func WrapError(inner error, message string) error {
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return &wrappedError{message, inner}
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}
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// WrapErrorf wraps an error with a message.
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func WrapErrorf(inner error, format string, args ...interface{}) error {
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return &wrappedError{fmt.Sprintf(format, args...), inner}
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}
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// MultiError combines multiple errors into a single error. If there are no errors,
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// nil is returned. If there is 1 error, it is returned. Otherwise, they are combined.
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func MultiError(errors ...error) error {
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// remove nils from the error list
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var nonNils []error
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for _, e := range errors {
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if e != nil {
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nonNils = append(nonNils, e)
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}
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}
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switch len(nonNils) {
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case 0:
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return nil
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case 1:
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return nonNils[0]
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default:
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return &multiError{
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message: "multiple errors encountered",
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errors: nonNils,
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}
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}
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}
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type multiError struct {
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message string
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errors []error
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}
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func (e *multiError) Message() string {
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return e.message
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}
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func (e *multiError) Error() string {
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result := e.message
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for _, e := range e.errors {
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result += fmt.Sprintf("\n %s", e)
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}
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return result
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}
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func (e *multiError) Errors() []error {
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return e.errors
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}
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type wrappedError struct {
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message string
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inner error
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}
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func (e *wrappedError) Message() string {
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return e.message
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}
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func (e *wrappedError) Error() string {
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return RolledUpErrorMessage(e)
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}
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func (e *wrappedError) Inner() error {
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return e.inner
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}
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func (e *wrappedError) Unwrap() error {
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return e.inner
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}
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