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mutex.rs
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mutex.rs
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use crate::base::*;
use crate::prelude::v1::*;
use crate::shim::*;
use crate::units::*;
pub type Mutex<T> = MutexImpl<T, MutexNormal>;
pub type RecursiveMutex<T> = MutexImpl<T, MutexRecursive>;
unsafe impl<T: Sync + Send, M> Send for MutexImpl<T, M> {}
unsafe impl<T: Sync + Send, M> Sync for MutexImpl<T, M> {}
/// Mutual exclusion access to a contained value. Can be recursive -
/// the current owner of a lock can re-lock it.
pub struct MutexImpl<T: ?Sized, M> {
mutex: M,
data: UnsafeCell<T>,
}
impl<T: ?Sized, M> fmt::Debug for MutexImpl<T, M>
where
M: MutexInnerImpl + fmt::Debug,
{
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "Mutex address: {:?}", self.mutex)
}
}
impl<T, M> MutexImpl<T, M>
where
M: MutexInnerImpl,
{
/// Create a new mutex with the given inner value
pub fn new(value: T) -> Result<Self, FreeRtosError> {
Ok(Self::from_parts(M::create()?, value))
}
/// Try to obtain a lock and mutable access to our inner value
pub fn lock<D: DurationTicks>(&self, max_wait: D) -> Result<MutexGuard<T, M>, FreeRtosError> {
self.mutex.take(max_wait)?;
Ok(MutexGuard {
__mutex: &self.mutex,
__data: &self.data,
})
}
/// Consume the mutex and return its inner value
pub fn into_inner(self) -> T {
self.into_parts().1
}
/// Get mutable reference to inner value.
///
/// This method does not lock the mutex because mutable reference guarantees exclusive access.
pub fn get_mut(&mut self) -> &mut T {
self.data.get_mut()
}
/// Create owning mutex from non-owning mutex and inner value.
///
/// It is safe to pass an already locked `mutex` although it is not recommended.
pub fn from_parts(mutex: M, value: T) -> Self {
Self {
mutex,
data: UnsafeCell::new(value),
}
}
/// Split owning mutex into non-owning mutex and inner value.
pub fn into_parts(self) -> (M, T) {
(self.mutex, self.data.into_inner())
}
/// Get mutable reference to inner non-owning mutex.
pub fn inner_mutex_mut(&mut self) -> &mut M {
&mut self.mutex
}
}
/// Holds the mutex until we are dropped
pub struct MutexGuard<'a, T: ?Sized + 'a, M: 'a>
where
M: MutexInnerImpl,
{
__mutex: &'a M,
__data: &'a UnsafeCell<T>,
}
impl<'mutex, T: ?Sized, M> Deref for MutexGuard<'mutex, T, M>
where
M: MutexInnerImpl,
{
type Target = T;
fn deref<'a>(&'a self) -> &'a T {
unsafe { &*self.__data.get() }
}
}
impl<'mutex, T: ?Sized, M> DerefMut for MutexGuard<'mutex, T, M>
where
M: MutexInnerImpl,
{
fn deref_mut<'a>(&'a mut self) -> &'a mut T {
unsafe { &mut *self.__data.get() }
}
}
impl<'a, T: ?Sized, M> Drop for MutexGuard<'a, T, M>
where
M: MutexInnerImpl,
{
fn drop(&mut self) {
self.__mutex.give();
}
}
pub trait MutexInnerImpl
where
Self: Sized,
{
fn create() -> Result<Self, FreeRtosError>;
fn take<D: DurationTicks>(&self, max_wait: D) -> Result<(), FreeRtosError>;
fn give(&self);
/// # Safety
///
/// `handle` must be a valid FreeRTOS mutex handle.
///
/// The type of `handle` (normal or recursive mutex) must match the type
/// of instance being created ([`MutexNormal`] or [`MutexRecursive`] respectively).
unsafe fn from_raw_handle(handle: FreeRtosSemaphoreHandle) -> Self;
fn raw_handle(&self) -> FreeRtosSemaphoreHandle;
}
pub struct MutexNormal(FreeRtosSemaphoreHandle);
impl MutexInnerImpl for MutexNormal {
fn create() -> Result<Self, FreeRtosError> {
let m = unsafe { freertos_rs_create_mutex() };
if m == 0 as *const _ {
return Err(FreeRtosError::OutOfMemory);
}
Ok(MutexNormal(m))
}
fn take<D: DurationTicks>(&self, max_wait: D) -> Result<(), FreeRtosError> {
let res = unsafe { freertos_rs_take_semaphore(self.0, max_wait.to_ticks()) };
if res != 0 {
return Err(FreeRtosError::MutexTimeout);
}
Ok(())
}
fn give(&self) {
unsafe {
freertos_rs_give_semaphore(self.0);
}
}
#[inline]
unsafe fn from_raw_handle(handle: FreeRtosSemaphoreHandle) -> Self {
Self(handle)
}
#[inline]
fn raw_handle(&self) -> FreeRtosSemaphoreHandle {
self.0
}
}
impl Drop for MutexNormal {
fn drop(&mut self) {
unsafe { freertos_rs_delete_semaphore(self.0) }
}
}
impl fmt::Debug for MutexNormal {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{:?}", self.0)
}
}
pub struct MutexRecursive(FreeRtosSemaphoreHandle);
impl MutexInnerImpl for MutexRecursive {
fn create() -> Result<Self, FreeRtosError> {
let m = unsafe { freertos_rs_create_recursive_mutex() };
if m == 0 as *const _ {
return Err(FreeRtosError::OutOfMemory);
}
Ok(MutexRecursive(m))
}
fn take<D: DurationTicks>(&self, max_wait: D) -> Result<(), FreeRtosError> {
let res = unsafe { freertos_rs_take_recursive_semaphore(self.0, max_wait.to_ticks()) };
if res != 0 {
return Err(FreeRtosError::MutexTimeout);
}
Ok(())
}
fn give(&self) {
unsafe {
freertos_rs_give_recursive_semaphore(self.0);
}
}
#[inline]
unsafe fn from_raw_handle(handle: FreeRtosSemaphoreHandle) -> Self {
Self(handle)
}
#[inline]
fn raw_handle(&self) -> FreeRtosSemaphoreHandle {
self.0
}
}
impl Drop for MutexRecursive {
fn drop(&mut self) {
unsafe { freertos_rs_delete_semaphore(self.0) }
}
}
impl fmt::Debug for MutexRecursive {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{:?}", self.0)
}
}