Adding upstream version 0.0~git20250501.71edba4.

Signed-off-by: Daniel Baumann <daniel@debian.org>

link.go

@@ -0,0 +1,166 @@
+package activitypub
+
+import (
+	"bytes"
+	"encoding/gob"
+	"fmt"
+
+	"github.com/valyala/fastjson"
+)
+
+// LinkTypes represent the valid values for a Link object
+var LinkTypes = ActivityVocabularyTypes{
+	LinkType,
+	MentionType,
+}
+
+type Links interface {
+	Link | IRI
+}
+
+// A Link is an indirect, qualified reference to a resource identified by a URL.
+// The fundamental model for links is established by [ RFC5988].
+// Many of the properties defined by the Activity Vocabulary allow values that are either instances of APObject or Link.
+// When a Link is used, it establishes a qualified relation connecting the subject
+// (the containing object) to the resource identified by the href.
+// Properties of the Link are properties of the reference as opposed to properties of the resource.
+type Link struct {
+	// Provides the globally unique identifier for an APObject or Link.
+	ID ID `jsonld:"id,omitempty"`
+	// Identifies the APObject or Link type. Multiple values may be specified.
+	Type ActivityVocabularyType `jsonld:"type,omitempty"`
+	// A simple, human-readable, plain-text name for the object.
+	// HTML markup MUST NOT be included. The name MAY be expressed using multiple language-tagged values.
+	Name NaturalLanguageValues `jsonld:"name,omitempty,collapsible"`
+	// A link relation associated with a Link. The value must conform to both the [HTML5] and
+	// [RFC5988](https://tools.ietf.org/html/rfc5988) "link relation" definitions.
+	// In the [HTML5], any string not containing the "space" U+0020, "tab" (U+0009), "LF" (U+000A),
+	// "FF" (U+000C), "CR" (U+000D) or "," (U+002C) characters can be used as a valid link relation.
+	Rel IRI `jsonld:"rel,omitempty"`
+	// When used on a Link, identifies the MIME media type of the referenced resource.
+	MediaType MimeType `jsonld:"mediaType,omitempty"`
+	// On a Link, specifies a hint as to the rendering height in device-independent pixels of the linked resource.
+	Height uint `jsonld:"height,omitempty"`
+	// On a Link, specifies a hint as to the rendering width in device-independent pixels of the linked resource.
+	Width uint `jsonld:"width,omitempty"`
+	// Identifies an entity that provides a preview of this object.
+	Preview Item `jsonld:"preview,omitempty"`
+	// The target resource pointed to by a Link.
+	Href IRI `jsonld:"href,omitempty"`
+	// Hints as to the language used by the target resource.
+	// Value must be a [BCP47](https://tools.ietf.org/html/bcp47) Language-Tag.
+	HrefLang LangRef `jsonld:"hrefLang,omitempty"`
+}
+
+// Mention is a specialized Link that represents an @mention.
+type Mention = Link
+
+// LinkNew initializes a new Link
+func LinkNew(id ID, typ ActivityVocabularyType) *Link {
+	if !LinkTypes.Contains(typ) {
+		typ = LinkType
+	}
+	return &Link{ID: id, Type: typ}
+}
+
+// MentionNew initializes a new Mention
+func MentionNew(id ID) *Mention {
+	return &Mention{ID: id, Type: MentionType}
+}
+
+// IsLink validates if current Link is a Link
+func (l Link) IsLink() bool {
+	return l.Type == LinkType || LinkTypes.Contains(l.Type)
+}
+
+// IsObject validates if current Link is an GetID
+func (l Link) IsObject() bool {
+	return l.Type == ObjectType || ObjectTypes.Contains(l.Type)
+}
+
+// IsCollection returns false for Link objects
+func (l Link) IsCollection() bool {
+	return false
+}
+
+// GetID returns the ID corresponding to the Link object
+func (l Link) GetID() ID {
+	return l.ID
+}
+
+// GetLink returns the IRI corresponding to the current Link
+func (l Link) GetLink() IRI {
+	return IRI(l.ID)
+}
+
+// GetType returns the Type corresponding to the Mention object
+func (l Link) GetType() ActivityVocabularyType {
+	return l.Type
+}
+
+// MarshalJSON encodes the receiver object to a JSON document.
+func (l Link) MarshalJSON() ([]byte, error) {
+	b := make([]byte, 0)
+	JSONWrite(&b, '{')
+
+	if JSONWriteLinkValue(&b, l) {
+		JSONWrite(&b, '}')
+		return b, nil
+	}
+	return nil, nil
+}
+
+// UnmarshalJSON decodes an incoming JSON document into the receiver object.
+func (l *Link) UnmarshalJSON(data []byte) error {
+	p := fastjson.Parser{}
+	val, err := p.ParseBytes(data)
+	if err != nil {
+		return err
+	}
+	return JSONLoadLink(val, l)
+}
+
+// UnmarshalBinary implements the encoding.BinaryUnmarshaler interface.
+func (l *Link) UnmarshalBinary(data []byte) error {
+	return l.GobDecode(data)
+}
+
+// MarshalBinary implements the encoding.BinaryMarshaler interface.
+func (l Link) MarshalBinary() ([]byte, error) {
+	return l.GobEncode()
+}
+
+func (l Link) GobEncode() ([]byte, error) {
+	mm := make(map[string][]byte)
+	hasData, err := mapLinkProperties(mm, l)
+	if err != nil {
+		return nil, err
+	}
+	if !hasData {
+		return []byte{}, nil
+	}
+	bb := bytes.Buffer{}
+	g := gob.NewEncoder(&bb)
+	if err := g.Encode(mm); err != nil {
+		return nil, err
+	}
+	return bb.Bytes(), nil
+}
+
+func (l *Link) GobDecode(data []byte) error {
+	if len(data) == 0 {
+		return nil
+	}
+	mm, err := gobDecodeObjectAsMap(data)
+	if err != nil {
+		return err
+	}
+	return unmapLinkProperties(mm, l)
+}
+
+func (l Link) Format(s fmt.State, verb rune) {
+	switch verb {
+	case 's', 'v':
+		_, _ = fmt.Fprintf(s, "%T[%s] {  }", l, l.Type)
+	}
+}