bacnet-objects

Build BACnet object state with [traits::BACnetObject] and [database::ObjectDatabase] in the Rusty BACnet workspace. The database owns registered objects and supports identifier-based lookup; object modules provide their property implementations.

The crate has no Tokio dependency. Using it alone does not start a transport, a server executor or event/COV delivery.

Features

There is no build with neither feature: the database boxes every object, so a heap-free device answers from a static table instead. ARMv6-M (thumbv6m-none-eabi) lacks compare-and-swap, which alloc::sync::Arc needs, so the crate doesn't build there. The design note has the details.

Initialize and read an object

Place an application directory beside a checkout named rusty-bacnet, then add this dependency block to the application's Cargo.toml. These are development-source paths, not a claim that the shown APIs are published; adjust the paths if your directories differ.

[dependencies]
bacnet-objects = { path = "../rusty-bacnet/crates/bacnet-objects" }
bacnet-types = { path = "../rusty-bacnet/crates/bacnet-types" }

Save this complete program as src/main.rs. It initializes an unattached Analog Input, transfers it to the database, then checks the stored identity, Present_Value and a missing-object lookup.

use bacnet_objects::analog::AnalogInputObject;
use bacnet_objects::database::ObjectDatabase;
use bacnet_types::enums::{EngineeringUnits, ObjectType, PropertyIdentifier};
use bacnet_types::primitives::{ObjectIdentifier, PropertyValue};

fn main() -> Result<(), bacnet_types::error::Error> {
    let object = ObjectIdentifier::new(ObjectType::ANALOG_INPUT, 7)?;
    let mut analog = AnalogInputObject::new(
        7,
        "supply-temperature",
        EngineeringUnits::DEGREES_CELSIUS,
    )?;
    analog.set_present_value(42.0);
    let mut database = ObjectDatabase::new();
    database.add(Box::new(analog))?;

    let stored = database.get(&object).expect("the object was registered");
    assert_eq!(stored.object_identifier(), object);
    assert_eq!(stored.object_name(), "supply-temperature");
    assert_eq!(
        stored.read_property(PropertyIdentifier::PRESENT_VALUE, None)?,
        PropertyValue::Real(42.0),
    );
    let absent = ObjectIdentifier::new(ObjectType::ANALOG_INPUT, 8)?;
    assert!(database.get(&absent).is_none());
    Ok(())
}

The direct setter above initializes an object before ownership transfer. AnalogInputObject::set_present_value bypasses running-server ownership, validation, intrinsic-event and COV processing. For live server updates, use BACnetServer::set_present_value_local and its documented policy instead of mutating a database object directly.

Device identity and executor ownership

Use [DeviceIdentity] and [device_identity::build_database_with_extra] when assembling a server database. The helper installs the Device and configured Network Ports, and seeds the Device's Object_List with the extra application objects. Adding a standalone analog object alone does not create a Device.

Objects read through a raw database return standalone state. A running BACnetServer supplies live executor-owned Device properties and lists through read_local; its shared database handle is not an equivalent live view. Never hold a database guard across network operations or shutdown. Durable objects can queue saves, so their final drop or the server's explicit stop may wait on storage; this example uses only an in-memory Analog Input.

The example establishes local object initialization, lookup and property access. It does not establish transport operation, event delivery, physical equipment behavior, timing or standards conformance. Consult each object's property and service documentation for its supported behavior.

Documentation profile

This README is included as the crate landing page and the program runs as a doctest. The docs.rs profile disables defaults, explicitly selects std and targets x86_64-unknown-linux-gnu, so it shows the hosted API, the file persistence backends included; it does not render the alloc-only build, and a local render does not establish a docs.rs deployment.