servicepoint-binding-c/src/connection.rs
2025-04-12 16:25:20 +02:00

139 lines
3.8 KiB
Rust

//! C functions for interacting with [SPConnection]s
//!
//! prefix `sp_connection_`
use std::ffi::{c_char, CStr};
use servicepoint::Connection;
use crate::{SPCommand, SPPacket};
/// 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());
/// ```
pub struct SPConnection(pub(crate) servicepoint::UdpConnection);
/// 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: *const c_char,
) -> *mut SPConnection {
assert!(!host.is_null());
let host = unsafe {CStr::from_ptr(host)}.to_str().expect("Bad encoding");
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: *const SPConnection,
packet: *mut SPPacket,
) -> bool {
assert!(!connection.is_null());
assert!(!packet.is_null());
let packet = unsafe {Box::from_raw(packet)};
unsafe {(*connection).0.send((*packet).0)}.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: *const SPConnection,
command: *mut SPCommand,
) -> bool {
assert!(!connection.is_null());
assert!(!command.is_null());
let command = (*unsafe {Box::from_raw(command)}).0;
unsafe{(*connection).0.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: *mut SPConnection) {
assert!(!connection.is_null());
_ = unsafe {Box::from_raw(connection)};
}