badguardhome/internal/agherr/agherr.go

129 lines
3.0 KiB
Go

// Package agherr contains AdGuard Home's error handling helpers.
package agherr
import (
"fmt"
"strings"
"github.com/AdguardTeam/golibs/log"
)
// Error is the constant error type.
type Error string
// Error implements the error interface for Error.
func (err Error) Error() (msg string) {
return string(err)
}
// manyError is an error containing several wrapped errors. It is created to be
// a simpler version of the API provided by github.com/joomcode/errorx.
type manyError struct {
message string
underlying []error
}
// Many wraps several errors and returns a single error.
//
// TODO(a.garipov): Add formatting to message.
func Many(message string, underlying ...error) (err error) {
err = &manyError{
message: message,
underlying: underlying,
}
return err
}
// Error implements the error interface for *manyError.
func (e *manyError) Error() (msg string) {
switch len(e.underlying) {
case 0:
return e.message
case 1:
return fmt.Sprintf("%s: %s", e.message, e.underlying[0])
default:
b := &strings.Builder{}
// Ignore errors, since strings.(*Buffer).Write never returns
// errors. We don't use aghstrings.WriteToBuilder here since
// this package should be importable for any other.
_, _ = fmt.Fprintf(b, "%s: %s (hidden: %s", e.message, e.underlying[0], e.underlying[1])
for _, u := range e.underlying[2:] {
// See comment above.
_, _ = fmt.Fprintf(b, ", %s", u)
}
// See comment above.
_, _ = b.WriteString(")")
return b.String()
}
}
// Unwrap implements the hidden errors.wrapper interface for *manyError.
func (e *manyError) Unwrap() (err error) {
if len(e.underlying) == 0 {
return nil
}
return e.underlying[0]
}
// wrapper is a copy of the hidden errors.wrapper interface for tests, linting,
// etc.
type wrapper interface {
Unwrap() error
}
// Annotate annotates the error with the message, unless the error is nil. This
// is a helper function to simplify code like this:
//
// func (f *foo) doStuff(s string) (err error) {
// defer func() {
// if err != nil {
// err = fmt.Errorf("bad foo string %q: %w", s, err)
// }
// }()
//
// // …
// }
//
// Instead, write:
//
// func (f *foo) doStuff(s string) (err error) {
// defer agherr.Annotate("bad foo string %q: %w", &err, s)
//
// // …
// }
//
// msg must contain the final ": %w" verb.
//
// TODO(a.garipov): Clearify the function usage.
func Annotate(msg string, errPtr *error, args ...interface{}) {
if errPtr == nil {
return
}
err := *errPtr
if err != nil {
args = append(args, err)
*errPtr = fmt.Errorf(msg, args...)
}
}
// LogPanic is a convinient helper function to log a panic in a goroutine. It
// should not be used where proper error handling is required.
func LogPanic(prefix string) {
if v := recover(); v != nil {
if prefix != "" {
log.Error("%s: recovered from panic: %v", prefix, v)
return
}
log.Error("recovered from panic: %v", v)
}
}