sdk/fidl/fuchsia.driver.framework/composite_node_spec.fidl

// Copyright 2022 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.driver.framework;

/// Represents a bind rule condition.
type Condition = strict enum {
    UNKNOWN = 0;
    ACCEPT = 1;
    REJECT = 2;
};

/// Represents a bind rule in a parent specification.
type BindRule = struct {
    /// Property key.
    key NodePropertyKey;

    /// Condition for evaluating the property values in
    /// the matching process. The values must be ACCEPT
    /// or REJECT.
    condition Condition;

    /// A list of property values. Must not be empty. The property
    /// values must be the same type.
    values vector<NodePropertyValue>:MAX_PROPERTY_COUNT;
};

/// Specification for a node that parents the composite node created from the
/// composite node specification.
type ParentSpec = struct {
    /// Parent's bind rules. Property keys must be unique. Must not be empty.
    bind_rules vector<BindRule>:MAX_PROPERTY_COUNT;

    /// Properties for matching against a composite driver's bind rules.
    /// Keys must be unique.
    properties vector<NodeProperty>:MAX_PROPERTY_COUNT;
};

/// Struct that represents a composite node specification.
type CompositeNodeSpec = table {
    /// The composite node spec's name.
    1: name string:MAX;

    /// The nodes in the composite node spec. Must not be empty. The first node is
    /// the primary node.
    2: parents vector<ParentSpec>:MAX;
};

/// Error codes for the CompositeNodeManager protocol.
type CompositeNodeSpecError = strict enum {
    /// An argument of the composite node spec was not provided.
    MISSING_ARGS = 1;
    /// The given composite node spec's `nodes` is empty.
    EMPTY_NODES = 2;
    /// The `name` in the given composite node spec is a duplicate of an already
    /// created composite node spec.
    ALREADY_EXISTS = 3;
};

/// Protocol through which board drivers can create composite node specs.
///
/// Composite node specs are created at runtime to dynamically bridge the
/// static bind rules of a composite driver with the dynamic bind properties
/// of nodes in the system so that the driver bind rules are more generic and reusable.
@discoverable
protocol CompositeNodeManager {
    /// Adds the given composite node specification to the driver framework.
    AddSpec(CompositeNodeSpec) -> () error CompositeNodeSpecError;
};