sdk/fidl/fuchsia.app.discover/story_module.fidl

// 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.app.discover;

using fuchsia.modular;
using fuchsia.mem;

const uint32 ENTITY_REFERENCE_MAX_LENGTH = 1024;
const uint32 MODULE_NAME_MAX_LENGTH = 512;
const uint32 STATE_KEY_MAX_LENGTH = 128;
const uint32 OUTPUT_NAME_MAX_LENGTH = 128;

using ModuleName = string:MODULE_NAME_MAX_LENGTH;
using OutputName = string:OUTPUT_NAME_MAX_LENGTH;
using StateKey = string:STATE_KEY_MAX_LENGTH;

[Discoverable]
protocol StoryModule {
    /// Writes the `entity_reference` to the module's `output_parameter_name`
    /// output. If no entity is provided, the output will be unset.
    /// Return happens upon completion of a successful write.
    WriteOutput(OutputName output_name, string:ENTITY_REFERENCE_MAX_LENGTH? entity_reference) -> () error OutputError;

    /// Starts a mod by issuing an intent to it or re-issues an intent to the mod
    /// with the given name.
    IssueIntent(fuchsia.modular.Intent intent, ModuleName mod_name) -> ();

    /// Writes the `instance_state` item with the given key to storage.
    WriteInstanceState(StateKey key, fuchsia.mem.Buffer value) -> () error StoryDiscoverError;

    /// Reads the `instance_state` item with the given key from storage.
    ReadInstanceState(StateKey key) -> (fuchsia.mem.Buffer value) error StoryDiscoverError;
};

/// Errors that can occur when writing to an output.
enum OutputError : int32 {
    /// If the output doesn't match a parameter defined in the module manifest
    /// for the action currently being handled by the module.
    UNKNOWN_NAME = 1;

    /// If the entity reference couldn't be resolved.
    UNKNOWN_ENTITY_REFERENCE = 2;

    /// If the entity type written doesn't match the type defined in the module
    /// manifest for the action currently being handled by the module.
    INVALID_ENTITY_TYPE = 3;
};