Crate atomic_ref [−] [src]
Atomic References
These types act similarially to the Atomic types from std::sync::atomic,
Except that instead of containing an integer type or a pointer, they contain
an Option<&'a T>
value.
Like other option values, these types present operations which, when used
correctly, synchronize updates between threads. This type is a form of
interior mutability, like Cell<T>
, RefCell<T>
, or Mutex<T>
.
To store an atomic reference in a static variable, a the macro
static_atomic_ref!
must be used. A static initializer like
ATOMIC_REF_INIT
is not possible due to the need to be generic over any
reference target type.
This type in static position is often used for lazy global initialization.
AtomicRef
may only contain Sized
types, as unsized types have wide
pointers which cannot be atomically written to or read from.
Examples
Static logger state
#[macro_use] extern crate atomic_ref; use atomic_ref::AtomicRef; use std::sync::atomic::Ordering; use std::io::{stdout, Write}; // Define the idea of a logger trait Logger { fn log(&self, msg: &str) {} } struct LoggerInfo { logger: &'static (Logger + Sync) } // The methods for working with our currently defined static logger static_atomic_ref! { static LOGGER: AtomicRef<LoggerInfo>; } fn log(msg: &str) -> bool { if let Some(info) = LOGGER.load(Ordering::SeqCst) { info.logger.log(msg); true } else { false } } fn set_logger(logger: Option<&'static LoggerInfo>) { LOGGER.store(logger, Ordering::SeqCst); } // Defining the standard out example logger struct StdoutLogger; impl Logger for StdoutLogger { fn log(&self, msg: &str) { stdout().write(msg.as_bytes()); } } static STDOUT_LOGGER: LoggerInfo = LoggerInfo { logger: &StdoutLogger }; fn main() { let res = log("This will fail"); assert!(!res); set_logger(Some(&STDOUT_LOGGER)); let res = log("This will succeed"); assert!(res); }
Macros
static_atomic_ref |
A macro to define a statically allocated |
Structs
AtomicRef |
A mutable Option<&'a, T> type which can be safely shared between threads. |
Constants
ATOMIC_U8_REF_INIT |
You will probably never need to use this type. It exists mostly for internal
use in the |