servicepoint-binding-c/src/connection.rs
Vinzenz Schroeter 6dcd26d1c1
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use NotNull for parameters
2025-04-12 13:01:27 +02:00

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Rust

//! C functions for interacting with [SPConnection]s
//!
//! prefix `sp_connection_`
//!
//! A connection to the display.
//!
//! # Examples
//!
//! ```C
//! CConnection connection = sp_connection_open("172.23.42.29:2342");
//! if (connection != NULL)
//! sp_connection_send_command(connection, sp_command_clear());
//! ```
use servicepoint::{Connection, Packet, TypedCommand, UdpConnection};
use std::ffi::{c_char, CStr};
use std::ptr::NonNull;
/// Creates a new instance of [SPConnection].
///
/// returns: NULL if connection fails, or connected instance
///
/// # Panics
///
/// - when `host` is null or an invalid host
///
/// # Safety
///
/// The caller has to make sure that:
///
/// - the returned instance is freed in some way, either by using a consuming function or
/// by explicitly calling `sp_connection_free`.
#[no_mangle]
pub unsafe extern "C" fn sp_connection_open(
host: NonNull<c_char>,
) -> *mut UdpConnection {
let host = unsafe { CStr::from_ptr(host.as_ptr()) }
.to_str()
.expect("Bad encoding");
let connection = match UdpConnection::open(host) {
Err(_) => return std::ptr::null_mut(),
Ok(value) => value,
};
Box::into_raw(Box::new(connection))
}
//#[no_mangle]
//pub unsafe extern "C" fn sp_connection_open_ipv4(
// host: SocketAddrV4,
//) -> *mut SPConnection {
// let connection = match servicepoint::UdpConnection::open(host) {
// Err(_) => return std::ptr::null_mut(),
// Ok(value) => value,
// };
//
// Box::into_raw(Box::new(SPConnection(connection)))
//}
// /// Creates a new instance of [SPUdpConnection] for testing that does not actually send anything.
// ///
// /// returns: a new instance. Will never return NULL.
// ///
// /// # Safety
// ///
// /// The caller has to make sure that:
// ///
// /// - the returned instance is freed in some way, either by using a consuming function or
// /// by explicitly calling `sp_connection_free`.
// #[no_mangle]
// pub unsafe extern "C" fn sp_connection_fake() -> NonNull<SPUdpConnection> {
// let result = Box::new(SPUdpConnection(servicepoint::Connection::Fake));
// NonNull::from(Box::leak(result))
// }
/// Sends a [SPPacket] to the display using the [SPConnection].
///
/// The passed `packet` gets consumed.
///
/// returns: true in case of success
///
/// # Panics
///
/// - when `connection` is NULL
/// - when `packet` is NULL
///
/// # Safety
///
/// The caller has to make sure that:
///
/// - `connection` points to a valid instance of [SPConnection]
/// - `packet` points to a valid instance of [SPPacket]
/// - `packet` is not used concurrently or after this call
#[no_mangle]
pub unsafe extern "C" fn sp_connection_send_packet(
connection: NonNull<UdpConnection>,
packet: NonNull<Packet>,
) -> bool {
let packet = unsafe { Box::from_raw(packet.as_ptr()) };
unsafe { connection.as_ref().send(*packet) }.is_ok()
}
/// Sends a [SPCommand] to the display using the [SPConnection].
///
/// The passed `command` gets consumed.
///
/// returns: true in case of success
///
/// # Panics
///
/// - when `connection` is NULL
/// - when `command` is NULL
///
/// # Safety
///
/// The caller has to make sure that:
///
/// - `connection` points to a valid instance of [SPConnection]
/// - `command` points to a valid instance of [SPPacket]
/// - `command` is not used concurrently or after this call
#[no_mangle]
pub unsafe extern "C" fn sp_connection_send_command(
connection: NonNull<UdpConnection>,
command: NonNull<TypedCommand>,
) -> bool {
let command = *unsafe { Box::from_raw(command.as_ptr()) };
unsafe { connection.as_ref().send(command) }.is_ok()
}
/// Closes and deallocates a [SPConnection].
///
/// # Panics
///
/// - when `connection` is NULL
///
/// # Safety
///
/// The caller has to make sure that:
///
/// - `connection` points to a valid [SPConnection]
/// - `connection` is not used concurrently or after this call
#[no_mangle]
pub unsafe extern "C" fn sp_connection_free(
connection: NonNull<UdpConnection>,
) {
_ = unsafe { Box::from_raw(connection.as_ptr()) };
}