QXmpp::Xml::Registry Class

class QXmpp::Xml::Registry

A global registry for type-driven parsing and serialization of XML extension elements. More...

Header:	`#include <QXmppXmlRegistry.h>`
Since:	QXmpp 1.16

List of all members, including inherited members

Static Public Members

void	registerElement(QXmpp::Xml::Scopes scopes)
void	serializeAll(QXmlStreamWriter &w, const std::vector<std::any> &items)
std::optional<std::any>	tryParse(QXmpp::Xml::Scope scope, const QDomElement &el)
void	unregisterElement()

Detailed Description

Registered types are matched by their XmlTag static member. When a stanza's parseExtension hook encounters an unknown element, Registry::tryParse is consulted. The first matching entry returns a typed std::any value which is stored in the stanza's QXmpp::Xml::Extensions container.

The registry is a process-wide singleton protected by a read-write lock. Lookup takes roughly 30 ns and is negligible compared to XML parse costs.

Registration

QXmpp::Xml::Registry::registerElement<MyFlag>(QXmpp::Xml::Scope::Message);
// Generic scope matches in every stanza context:
QXmpp::Xml::Registry::registerElement<MyDebugTag>(QXmpp::Xml::Scope::Generic);

Constraints on T

T must satisfy:

T::XmlTag — a tag/namespace pair (see QXmpp::Private::HasXmlTag).
One of the three parse styles (QXmpp::Private::DomParsable):
- static std::optional<T> T::fromDom(const QDomElement &)
- bool T::parse(const QDomElement &)
- void T::parse(const QDomElement &)
void T::toXml(QXmlStreamWriter *) const (serialization).

Member Function Documentation

`[static]` template <typename T> requires QXmpp::Private::HasXmlTag<T> && QXmpp::Private::DomParsable<T> && QXmpp::Private::QXmlStreamSerializeable<T> void Registry::registerElement(QXmpp::Xml::Scopes scopes)

Registers T for the given scopes.

If a type with the same XmlTag is already registered, the previous entry is replaced and a warning is emitted.

`[static]` void Registry::serializeAll(QXmlStreamWriter &w, const std::vector<std::any> &items)

Serializes all items to w by dispatching to each item's registered serializer. QXmpp::Xml::Element fallback items are handled directly. Items with no registered serializer emit a warning and are skipped.

`[static]` std::optional<std::any> Registry::tryParse(QXmpp::Xml::Scope scope, const QDomElement &el)

Attempts to parse el as a registered extension type for scope.

Returns a typed std::any on success, or std::nullopt if no matching registration is found.

`[static]` template <typename T> void Registry::unregisterElement()

Removes the registration for T.

After this call, unknown elements with T's tag/namespace are stored as a QXmpp::Xml::Element fallback instead.

Contents