// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

library fuchsia.ui.gfx;

using zx;

/// Token that uniquely identifies an attachment point for a subgraph in the
/// global scene graph.  Each `ImportToken` has exactly one corresponding
/// `ExportToken`.
///
/// A Scenic client can reference contents from another client by creating a
/// typed resource using this token.  The other client must also create a
/// correspondingly typed resource using the corresponding `ExportToken`.
///
/// The exact nature of the inter-client reference depends on the specific
/// resources created from the tokens.  For example, creating a `ViewHolder`
/// resource from this token allows a client to embed another client's `View`.
resource struct ImportToken {
    zx.handle:EVENTPAIR value;
};

/// Token that uniquely identifies a root point for a subgraph in the global
/// scene graph. Each `ExportToken` has exactly one corresponding `ImportToken`.
///
/// A Scenic client can have its contents referenced from another client by
/// creating a typed resource using this token.  The other client must also
/// create a correspondingly typed resource using the corresponding
/// `ImportToken`.
///
/// The exact nature of the inter-client reference depends on the specific
/// resources created from the tokens.  For example, creating a `View`
/// resource from this token allows everything attached to the `View` to be
/// embedded in another clients `ViewHolder`.
resource struct ExportToken {
    zx.handle:EVENTPAIR value;
};