Function attachmentArgForDestination

internal/attachments/references.go:350–364

attachmentArgForDestination is where the two halves of this package meet: it takes a markdown destination and answers which attached file, if any, it names. Only a local path can name one, and markdown offers several spellings for the same path, so each is resolved to an absolute path and looked up

(dest string, byPath map[string]int)

// Only a local path can name one, and markdown offers several spellings for
// the same path, so each is resolved to an absolute path and looked up.
func attachmentArgForDestination(dest string, byPath map[string]int) (int, bool) {
	if dest == "" || strings.HasPrefix(dest, "#") || isRemoteDestination(dest) {
		return 0, false
	}
	for _, path := range candidatePaths(dest) {
		abs, err := filepath.Abs(path)
		if err != nil {
			continue
		}
		if i, ok := byPath[abs]; ok {
			return i, true
		}
	}
	return 0, false
}

// isRemoteDestination reports whether a destination addresses somewhere other
// than the filesystem, so that an attached file is never confused with a URI.