element_manager

Reviewed on: 2021-01-21

element_manager is a component that implements the fuchsia.element.Manager protocol. element_manager is not intended to be used on its own, but instead composed into a session as a child.

element_manager launches all elements proposed using Manager in a collection.

Building

To add this project to your build, append --with //src/session/bin/element_manager to the fx set invocation.

Running

To include element_manager in a session, add the following to the session's component manifest.

Once available, session manifests should instead include element_manager.shard.cml. Related monorail issue: fxbug.dev/68107.

{
    children: [
        {
            name: "element_manager",
            url: "fuchsia-pkg://fuchsia.com/element_manager#meta/element_manager.cm",
            startup: "eager",
        },
    ],
    capabilities: [
        { protocol: "fuchsia.element.Manager" },
    ],
    offer: [
        {
            protocol: [ "fuchsia.logger.LogSink" ],
            from: "parent",
            to: [ "#element_manager" ],
        },
    ],
    expose: [
        {
            protocol: "fuchsia.element.Manager",
            from: "#element_manager",
        },
    ],
}

Testing

Unit tests for element_manager are available in the element_manager_tests package.

$ fx test element_manager_tests

Source layout

The entrypoint is located in src/main.rs. Unit tests are co-located with the code.

Element annotations

element_manager writes annotations in the namespace “element_manager”.

Namespace	Key	Value [type]	Description
element_manager	url	Element component URL [text]	Set from the value from component_url in the proposed element spec. The GraphicalPresenter implementation can use this annotation to determine which component is associated with an element's view.