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#![warn(unsafe_op_in_unsafe_fn)]
#![allow(non_camel_case_types)]
#![allow(unused_unsafe)]
#![allow(clippy::missing_safety_doc)]
#![allow(clippy::new_without_default)]
/// A simple little state machine for a system's status. This module
/// represents the Rust library being exposed via FFI.
mod hittr {
#[derive(Clone, Copy, PartialEq, Eq)]
pub enum Status {
Ready,
Running { count: u32 },
Failed,
}
pub struct System {
pub status: Status,
}
/// ```c
/// typedef struct hittr_system_t hittr_system_t;
/// ```
impl System {
pub fn new() -> System {
System {
status: Status::Ready,
}
}
pub fn new_network(_port: u16) -> Result<System, ()> {
// (this constructor is just to have an example of a fallible constructor)
Ok(System {
status: Status::Ready,
})
}
pub fn run(&mut self) {
if self.status != Status::Ready {
self.status = Status::Failed;
} else {
self.status = Status::Running { count: 0 };
}
}
pub fn count_hit(&mut self) {
if let Status::Running { count } = self.status {
if count >= 5 {
self.status = Status::Failed;
return;
}
self.status = Status::Running { count: count + 1 };
} else {
self.status = Status::Failed;
}
}
}
}
mod status {
use super::hittr::Status;
use ffizz_passby::Value;
#[allow(non_camel_case_types)]
#[repr(C)]
pub struct hittr_status_t {
pub status: u8,
pub count: u32,
}
pub const HITTR_STATUS_READY: u8 = 1;
pub const HITTR_STATUS_RUNNING: u8 = 2;
pub const HITTR_STATUS_FAILED: u8 = 3;
impl Into<Status> for hittr_status_t {
fn into(self) -> Status {
match self.status {
HITTR_STATUS_READY => Status::Ready,
HITTR_STATUS_RUNNING => Status::Running { count: self.count },
HITTR_STATUS_FAILED => Status::Failed,
_ => panic!("invalid status value"),
}
}
}
impl From<Status> for hittr_status_t {
fn from(rval: Status) -> hittr_status_t {
match rval {
Status::Ready => hittr_status_t {
status: HITTR_STATUS_READY,
count: 0,
},
Status::Running { count } => hittr_status_t {
status: HITTR_STATUS_RUNNING,
count,
},
Status::Failed => hittr_status_t {
status: HITTR_STATUS_FAILED,
count: 0,
},
}
}
}
pub type StatusValue = Value<Status, hittr_status_t>;
}
use ffizz_passby::Boxed;
use hittr::*;
use status::*;
type BoxedSystem = Boxed<System>;
/// Create a new Hittr system.
///
/// # Safety
///
/// The returned hittr_system_t must be freed with hittr_system_free.
///
/// ```c
/// hittr_system_t *hittr_system_new();
/// ```
#[no_mangle]
pub unsafe extern "C" fn hittr_system_new() -> *mut System {
let sys = System::new();
// SAFETY: function docs indicate value must be freed
unsafe { BoxedSystem::return_val(sys) }
}
/// Create a new Hittr system with a network port. This returns true
/// on success. On failure, the output argument is not changed.
///
/// # Safety
///
/// The system_out argument must ne non-NULL and point to a valid, properly aligned
/// `*hittr_system_t`. The returned hittr_system_t must be freed with hittr_system_free.
///
/// ```c
/// bool hittr_system_new_network(hittr_system_t **system_out, uint16_t port);
/// ```
#[no_mangle]
pub unsafe extern "C" fn hittr_system_new_network(system_out: *mut *mut System, port: u16) -> bool {
if let Ok(sys) = System::new_network(port) {
// SAFETY: see docstring
unsafe { BoxedSystem::to_out_param(sys, system_out) }
true
} else {
false
}
}
/// Free a Hittr system.
///
/// # Safety
///
/// The system must be non-NULL and point to a valid hittr_system_t. After this call it is no
/// longer valid and must not be used.
///
/// ```c
/// void hittr_system_free(hittr_system_t *system);
/// ```
#[no_mangle]
pub unsafe extern "C" fn hittr_system_free(system: *mut System) {
// SAFETY:
// - system is valid and not NULL (see docstring)
// - caller will not use system after this call (see docstring)
unsafe { BoxedSystem::take_nonnull(system) };
// (System is implicitly dropped)
}
/// Run the Hittr system.
///
/// If the sytem is already running, it will enter the failed state.
///
/// # Safety
///
/// The system must be non-NULL and point to a valid hittr_system_t.
///
/// ```c
/// void hittr_system_run(hittr_system_t *system);
/// ```
#[no_mangle]
pub unsafe extern "C" fn hittr_system_run(system: *mut System) {
// SAFETY:
// - system is not NULL and valid (see docstring)
// - system is valid for the life of this function (documented as not threadsafe)
// - system will not be accessed during the life of this function (documented as not threadsafe)
unsafe {
BoxedSystem::with_ref_mut_nonnull(system, |system| {
system.run();
});
}
}
/// Record a hit on thi Hittr system.
///
/// If the sytem is not running, it will enter the failed state. If it counts 5
/// or more hits, it will enter the failed.state.
///
/// # Safety
///
/// The system must be non-NULL and point to a valid hittr_system_t.
///
/// ```c
/// void hittr_system_count_hit(hittr_system_t *system);
/// ```
#[no_mangle]
pub unsafe extern "C" fn hittr_system_count_hit(system: *mut System) {
// SAFETY:
// - system is not NULL and valid (see docstring)
// - system is valid for the life of this function (documented as not threadsafe)
// - system will not be accessed during the life of this function (documented as not threadsafe)
unsafe {
BoxedSystem::with_ref_mut_nonnull(system, |system| {
system.count_hit();
});
}
}
/// Get the current system status.
///
/// The system must be non-NULL and point to a valid hittr_system_t.
///
/// ```c
/// hittr_status_t hittr_system_status(hittr_system_t *system);
/// ```
#[no_mangle]
pub unsafe extern "C" fn hittr_system_status(system: *const System) -> hittr_status_t {
// SAFETY:
// - system is not NULL and valid (see docstring)
// - system is valid for the life of this function (documented as not threadsafe)
// - system will not be modified during the life of this function (documented as not threadsafe)
unsafe {
BoxedSystem::with_ref_nonnull(system, |system| {
// SAFETY:
// - hittr_status_t is not allocated, so no issues
unsafe { StatusValue::return_val(system.status) }
})
}
}
fn main() {
let sys = unsafe { hittr_system_new() };
let st = unsafe { hittr_system_status(sys) };
assert_eq!(st.status, HITTR_STATUS_READY);
assert_eq!(st.count, 0);
unsafe { hittr_system_run(sys) };
let st = unsafe { hittr_system_status(sys) };
assert_eq!(st.status, HITTR_STATUS_RUNNING);
assert_eq!(st.count, 0);
for i in 1..=5 {
unsafe { hittr_system_count_hit(sys) };
let st = unsafe { hittr_system_status(sys) };
assert_eq!(st.status, HITTR_STATUS_RUNNING);
assert_eq!(st.count, i);
}
unsafe { hittr_system_count_hit(sys) }; // 5th hit causes system failure
let st = unsafe { hittr_system_status(sys) };
assert_eq!(st.status, HITTR_STATUS_FAILED);
assert_eq!(st.count, 0);
unsafe { hittr_system_free(sys) };
// this is awkward to call from Rust, but would be pretty natural in C
let mut sys: *mut System = std::ptr::null_mut();
assert!(unsafe { hittr_system_new_network(&mut sys as *mut *mut System, 1300) });
let st = unsafe { hittr_system_status(sys) };
assert_eq!(st.status, HITTR_STATUS_READY);
assert_eq!(st.count, 0);
}