mirror of
https://github.com/tailscale/tailscale.git
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137 lines
3.1 KiB
Go
137 lines
3.1 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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// Package multierr provides a simple multiple-error type.
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// It was inspired by github.com/go-multierror/multierror.
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package multierr
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import (
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"errors"
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"slices"
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"strings"
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)
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// An Error represents multiple errors.
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type Error struct {
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errs []error
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}
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// Error implements the error interface.
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func (e Error) Error() string {
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s := new(strings.Builder)
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s.WriteString("multiple errors:")
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for _, err := range e.errs {
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s.WriteString("\n\t")
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s.WriteString(err.Error())
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}
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return s.String()
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}
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// Errors returns a slice containing all errors in e.
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func (e Error) Errors() []error {
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return slices.Clone(e.errs)
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}
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// Unwrap returns the underlying errors as-is.
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func (e Error) Unwrap() []error {
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// Do not clone since Unwrap requires callers to not mutate the slice.
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// See the documentation in the Go "errors" package.
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return e.errs
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}
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// New returns an error composed from errs.
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// Some errors in errs get special treatment:
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// - nil errors are discarded
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// - errors of type Error are expanded into the top level
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//
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// If the resulting slice has length 0, New returns nil.
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// If the resulting slice has length 1, New returns that error.
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// If the resulting slice has length > 1, New returns that slice as an Error.
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func New(errs ...error) error {
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// First count the number of errors to avoid allocating.
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var n int
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var errFirst error
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for _, e := range errs {
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switch e := e.(type) {
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case nil:
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continue
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case Error:
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n += len(e.errs)
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if errFirst == nil && len(e.errs) > 0 {
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errFirst = e.errs[0]
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}
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default:
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n++
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if errFirst == nil {
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errFirst = e
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}
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}
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}
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if n <= 1 {
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return errFirst // nil if n == 0
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}
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// More than one error, allocate slice and construct the multi-error.
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dst := make([]error, 0, n)
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for _, e := range errs {
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switch e := e.(type) {
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case nil:
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continue
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case Error:
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dst = append(dst, e.errs...)
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default:
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dst = append(dst, e)
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}
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}
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return Error{errs: dst}
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}
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// Is reports whether any error in e matches target.
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func (e Error) Is(target error) bool {
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for _, err := range e.errs {
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if errors.Is(err, target) {
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return true
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}
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}
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return false
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}
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// As finds the first error in e that matches target, and if any is found,
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// sets target to that error value and returns true. Otherwise, it returns false.
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func (e Error) As(target any) bool {
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for _, err := range e.errs {
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if ok := errors.As(err, target); ok {
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return true
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}
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}
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return false
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}
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// Range performs a pre-order, depth-first iteration of the error tree
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// by successively unwrapping all error values.
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// For each iteration it calls fn with the current error value and
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// stops iteration if it ever reports false.
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func Range(err error, fn func(error) bool) bool {
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if err == nil {
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return true
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}
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if !fn(err) {
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return false
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}
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switch err := err.(type) {
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case interface{ Unwrap() error }:
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if err := err.Unwrap(); err != nil {
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if !Range(err, fn) {
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return false
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}
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}
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case interface{ Unwrap() []error }:
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for _, err := range err.Unwrap() {
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if !Range(err, fn) {
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return false
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}
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}
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}
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return true
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}
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