diff --git a/internal/fmsg/errors.go b/internal/fmsg/errors.go new file mode 100644 index 0000000..079c555 --- /dev/null +++ b/internal/fmsg/errors.go @@ -0,0 +1,72 @@ +package fmsg + +import ( + "fmt" + "reflect" +) + +// baseError implements a basic error container +type baseError struct { + Err error +} + +func (e *baseError) Error() string { + return e.Err.Error() +} + +func (e *baseError) Unwrap() error { + return e.Err +} + +// BaseError implements an error container with a user-facing message +type BaseError struct { + message string + baseError +} + +// Message returns a user-facing error message +func (e *BaseError) Message() string { + return e.message +} + +// WrapError wraps an error with a corresponding message. +func WrapError(err error, a ...any) error { + if err == nil { + return nil + } + return wrapError(err, fmt.Sprintln(a...)) +} + +// WrapErrorSuffix wraps an error with a corresponding message with err at the end of the message. +func WrapErrorSuffix(err error, a ...any) error { + if err == nil { + return nil + } + return wrapError(err, fmt.Sprintln(append(a, err)...)) +} + +// WrapErrorFunc wraps an error with a corresponding message returned by f. +func WrapErrorFunc(err error, f func(err error) string) error { + if err == nil { + return nil + } + return wrapError(err, f(err)) +} + +func wrapError(err error, message string) *BaseError { + return &BaseError{message, baseError{err}} +} + +var ( + baseErrorType = reflect.TypeFor[*BaseError]() +) + +func AsBaseError(err error, target **BaseError) bool { + v := reflect.ValueOf(err) + if !v.CanConvert(baseErrorType) { + return false + } + + *target = v.Convert(baseErrorType).Interface().(*BaseError) + return true +} diff --git a/internal/fmsg/fmsg.go b/internal/fmsg/fmsg.go new file mode 100644 index 0000000..40d3410 --- /dev/null +++ b/internal/fmsg/fmsg.go @@ -0,0 +1,2 @@ +// Package fmsg provides various functions for output messages. +package fmsg