101 lines
2.0 KiB
Go
101 lines
2.0 KiB
Go
package adverr
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import (
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"errors"
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"reflect"
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"strings"
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)
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// Error is a wrapper for error with stack trace
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type Error struct {
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msg string
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callTrace *CallTrace
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tmpl *ErrTmpl
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cause error
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}
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// New returns a new Error with the given message
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func New(msg string) *Error {
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return &Error{
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msg: msg,
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cause: nil,
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tmpl: nil,
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callTrace: Trace(2),
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}
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}
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// Wrap returns a new Error with the given message which is caused by cause
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func Wrap(msg string, cause error) *Error {
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return &Error{
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msg: msg,
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cause: cause,
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callTrace: Trace(2),
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}
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}
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func errtype(err error) string {
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if e, ok := err.(*Error); ok && e.tmpl != nil {
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return errtype(e.tmpl)
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} else if tmpl, ok := err.(*ErrTmpl); ok {
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return tmpl.name
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}
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t := reflect.TypeOf(err)
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for t.Kind() == reflect.Ptr {
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t = t.Elem()
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}
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return t.PkgPath() + "." + t.Name()
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}
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func (e *Error) Unwrap() error {
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return e.cause
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}
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func (e *Error) Error() string {
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b := new(strings.Builder)
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printErr(e, b)
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return b.String()
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}
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// Is implements the error equality function used by errors.Is()
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// It returns true if the error is the same instance or is created using the same ErrTmpl
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func (e *Error) Is(target error) bool {
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// same error instance
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if target == e {
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return true
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}
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// no template used, therefore no equality possible
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if e.tmpl == nil {
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return false
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}
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// same template, therefore errors are equal to another
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if tErr, ok := target.(*Error); ok {
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return tErr.tmpl == e.tmpl
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}
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return false
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}
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func printErr(err error, b *strings.Builder) {
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if e, ok := err.(*Error); ok {
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b.WriteString(errtype(e))
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b.WriteString(": ")
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b.WriteString(e.msg)
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b.WriteString("\n")
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b.WriteString(e.callTrace.String())
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} else {
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b.WriteString(errtype(err))
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b.WriteString(": ")
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b.WriteString(err.Error())
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b.WriteString("\n")
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}
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cause := errors.Unwrap(err)
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if cause != nil {
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b.WriteString("Caused by ")
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printErr(cause, b)
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}
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}
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