favicon_errors.go RawHistoryFolder

1package port
2
3import "errors"
4
5// ErrFaviconMiss is returned when a favicon cannot be found or served from allowed sources.
6var ErrFaviconMiss = errors.New("favicon miss")
7
8// ErrFaviconBusy is returned to direct refresh callers when the shared
9// refresh admission budget is exhausted. It is deliberately distinct from
10// ErrFaviconMiss: overload is not a miss and must never read as success.
11var ErrFaviconBusy = errors.New("favicon refresh overloaded")
12
13// ErrFaviconShutdown is returned to refresh callers arriving after the
14// use case began closing. Like overload, it is distinct from a miss.
15var ErrFaviconShutdown = errors.New("favicon refresh shutting down")
16
17// FaviconFetchError classifies a failed fetch while preserving
18// ErrFaviconMiss matching for existing callers. StatusCode carries the
19// HTTP status for HTTP failures and is zero for validation, transport,
20// cancellation, or DNS failures, which must never be negatively cached.
21type FaviconFetchError struct {
22	StatusCode int
23}
24
25func (e *FaviconFetchError) Error() string {
26	if e == nil || e.StatusCode == 0 {
27		return "favicon fetch failed"
28	}
29	return "favicon fetch failed: unexpected HTTP status"
30}
31
32// Is preserves ErrFaviconMiss matching so callers that treat every fetch
33// failure as a miss keep working; use FetchStatusCode for classification.
34func (*FaviconFetchError) Is(target error) bool {
35	return target == ErrFaviconMiss
36}
37
38// FetchStatusCode returns the HTTP status carried by err, if any.
39func FetchStatusCode(err error) (int, bool) {
40	var fetchErr *FaviconFetchError
41	if errors.As(err, &fetchErr) && fetchErr != nil {
42		return fetchErr.StatusCode, true
43	}
44	return 0, false
45}
46
47// ErrFaviconInvalidInput is returned when favicon storage receives invalid input.
48var ErrFaviconInvalidInput = errors.New("invalid favicon input")