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//! Provides `RwLock`, `RwLockReadGuard`, `RwLockWriteGuard`
pub use implementation::{RwLock, RwLockReadGuard, RwLockWriteGuard};
#[cfg(feature = "std")]
use std::sync as implementation;
#[cfg(not(feature = "std"))]
mod implementation {
use crate::sync::{LockResult, TryLockError, TryLockResult};
use core::fmt;
pub use spin::rwlock::{RwLockReadGuard, RwLockWriteGuard};
/// Fallback implementation of `RwLock` from the standard library.
pub struct RwLock<T: ?Sized> {
inner: spin::RwLock<T>,
}
impl<T> RwLock<T> {
/// Creates a new instance of an `RwLock<T>` which is unlocked.
///
/// See the standard library for further details.
pub const fn new(t: T) -> RwLock<T> {
Self {
inner: spin::RwLock::new(t),
}
}
}
impl<T: ?Sized> RwLock<T> {
/// Locks this `RwLock` with shared read access, blocking the current thread
/// until it can be acquired.
///
/// See the standard library for further details.
pub fn read(&self) -> LockResult<RwLockReadGuard<'_, T>> {
Ok(self.inner.read())
}
/// Attempts to acquire this `RwLock` with shared read access.
///
/// See the standard library for further details.
pub fn try_read(&self) -> TryLockResult<RwLockReadGuard<'_, T>> {
self.inner.try_read().ok_or(TryLockError::WouldBlock)
}
/// Locks this `RwLock` with exclusive write access, blocking the current
/// thread until it can be acquired.
///
/// See the standard library for further details.
pub fn write(&self) -> LockResult<RwLockWriteGuard<'_, T>> {
Ok(self.inner.write())
}
/// Attempts to lock this `RwLock` with exclusive write access.
///
/// See the standard library for further details.
pub fn try_write(&self) -> TryLockResult<RwLockWriteGuard<'_, T>> {
self.inner.try_write().ok_or(TryLockError::WouldBlock)
}
/// Determines whether the lock is poisoned.
///
/// See the standard library for further details.
pub fn is_poisoned(&self) -> bool {
false
}
/// Clear the poisoned state from a lock.
///
/// See the standard library for further details.
pub fn clear_poison(&self) {
// no-op
}
/// Consumes this `RwLock`, returning the underlying data.
///
/// See the standard library for further details.
pub fn into_inner(self) -> LockResult<T>
where
T: Sized,
{
Ok(self.inner.into_inner())
}
/// Returns a mutable reference to the underlying data.
///
/// See the standard library for further details.
pub fn get_mut(&mut self) -> LockResult<&mut T> {
Ok(self.inner.get_mut())
}
}
impl<T: ?Sized + fmt::Debug> fmt::Debug for RwLock<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut d = f.debug_struct("RwLock");
match self.try_read() {
Ok(guard) => {
d.field("data", &&*guard);
}
Err(TryLockError::Poisoned(err)) => {
d.field("data", &&**err.get_ref());
}
Err(TryLockError::WouldBlock) => {
d.field("data", &format_args!("<locked>"));
}
}
d.field("poisoned", &false);
d.finish_non_exhaustive()
}
}
impl<T: Default> Default for RwLock<T> {
fn default() -> RwLock<T> {
RwLock::new(Default::default())
}
}
impl<T> From<T> for RwLock<T> {
fn from(t: T) -> Self {
RwLock::new(t)
}
}
}