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package cli
import (
"fmt"
"io"
"os"
"strings"
)
// OsExiter is the function used when the app exits. If not set defaults to os.Exit.
var OsExiter = os.Exit
// ErrWriter is used to write errors to the user. This can be anything
// implementing the io.Writer interface and defaults to os.Stderr.
var ErrWriter io.Writer = os.Stderr
// MultiError is an error that wraps multiple errors.
type MultiError interface {
error
// Errors returns a copy of the errors slice
Errors() []error
}
// NewMultiError creates a new MultiError. Pass in one or more errors.
func newMultiError(err ...error) MultiError {
ret := multiError(err)
return &ret
}
type multiError []error
// Error implements the error interface.
func (m *multiError) Error() string {
errs := make([]string, len(*m))
for i, err := range *m {
errs[i] = err.Error()
}
return strings.Join(errs, "\n")
}
// Errors returns a copy of the errors slice
func (m *multiError) Errors() []error {
errs := make([]error, len(*m))
for _, err := range *m {
errs = append(errs, err)
}
return errs
}
// ExitCoder is the interface checked by `App` and `Command` for a custom exit
// code
type ExitCoder interface {
error
ExitCode() int
}
type exitError struct {
exitCode int
message string
}
// Exit wraps a message and exit code into an ExitCoder suitable for handling by
// HandleExitCoder
func Exit(message string, exitCode int) ExitCoder {
return &exitError{
exitCode: exitCode,
message: message,
}
}
func (ee *exitError) Error() string {
return ee.message
}
func (ee *exitError) ExitCode() int {
return ee.exitCode
}
// HandleExitCoder checks if the error fulfills the ExitCoder interface, and if
// so prints the error to stderr (if it is non-empty) and calls OsExiter with the
// given exit code. If the given error is a MultiError, then this func is
// called on all members of the Errors slice.
func HandleExitCoder(err error) {
if err == nil {
return
}
if exitErr, ok := err.(ExitCoder); ok {
if err.Error() != "" {
fmt.Fprintln(ErrWriter, err)
}
OsExiter(exitErr.ExitCode())
return
}
if multiErr, ok := err.(MultiError); ok {
for _, merr := range multiErr.Errors() {
HandleExitCoder(merr)
}
return
}
if err.Error() != "" {
fmt.Fprintln(ErrWriter, err)
}
OsExiter(1)
}