atom/outOfLineContent.go

package atom

import (
	"encoding/xml"
	"fmt"
	"mime"
)

type OutOfLineContent struct {
	XMLName xml.Name `xml:"content"`
	*CommonAttributes
	Type MediaType `xml:"type,attr,omitempty"`
	SRC  IRI       `xml:"src,attr"`
}

// newOutOfLineContent creates a new OutOfLineContent. It returns a
// *OutOfLineContent and an error.
func newOutOfLineContent(mediaType string, content any) (*OutOfLineContent, error) {
	if mediaType, _, err := mime.ParseMediaType(mediaType); err != nil {
		return nil, fmt.Errorf("media type %v incompatible with out of line content", mediaType)
	}

	iri, ok := content.(IRI)
	if !ok {
		return nil, fmt.Errorf("content type %T incompatible with out of line content", content)
	}

	if !isValidIRI(iri) {
		return nil, fmt.Errorf("content %v not a valid uri", iri)
	}

	return &OutOfLineContent{Type: MediaType(mediaType), SRC: iri}, nil
}

// isContent checks whether the OutOfLineContent is a Content. It returns a
// bool.
func (o *OutOfLineContent) isContent() bool { return true }

// hasSRC checks whether the OutOfLineContent has a SRC attribute. It returns a
// bool.
func (o *OutOfLineContent) hasSRC() bool { return true }

// getType returns the Type of the OutOfLineContent as a string.
func (o *OutOfLineContent) getType() string { return string(o.Type) }

// Check checks the OutOfLineContent for incompatibilities with RFC4287. It
// returns an error.
func (o *OutOfLineContent) Check() error {
	mediaType := o.getType()

	if mediaType, _, err := mime.ParseMediaType(mediaType); err != nil {
		return fmt.Errorf("type attribute %v incompatible with out of line content", mediaType)
	}

	if isCompositeMediaType(mediaType) {
		return fmt.Errorf("type attribute of out of line content %v must not be a composite type", o)
	}

	if o.SRC == "" {
		return fmt.Errorf("src attribute of out of line content %v empty", o)
	}

	return nil
}