validatePayload function

void validatePayload(List<CatalogApi> catalogs, Iterable<AgentToRendererMessage> payload)

Checks payload the way a renderer holding catalogs would.

The check is stateless: it sees one payload, with no record of what earlier payloads sent. A surface that the payload creates is checked in full, so its components must be valid and reachable from the root, and their references must resolve once every message in the payload is applied: a component may name a child that a later message adds. A surface that the payload only updates may already hold components, so references to components outside the payload and a missing root are accepted there. Each of its components is still checked against a catalog that defines all of them, and the surface passes if one such catalog accepts it.

To check a payload against what earlier payloads sent, keep a RendererState and call its RendererState.apply and RendererState.checkTopology inside RendererState.transaction, so a rejected response is rolled back whole.

Each message must state a version that the catalogs' protocol version accepts, such as v0.9 or v0.9.1 for v0.9 catalogs and v1.0 for v1.0 catalogs.

Throws A2uiValidationError, or a subclass such as A2uiIntegrityError, describing the first problem found if a renderer holding catalogs would reject the payload, and A2uiCatalogError if catalogs is empty or they target protocol versions whose messages differ.

Implementation

void validatePayload(
  List<CatalogApi> catalogs,
  Iterable<AgentToRendererMessage> payload,
) {
  final RendererState state = createPayloadState(catalogs);
  try {
    state.checkTopology(state.apply(payload));
  } finally {
    state.dispose();
  }
}