Struct Gutex

pub struct Gutex<T> {
    group: Arc<GutexGroup>,
    active: UnsafeCell<usize>,
    value: UnsafeCell<T>,
}

A mutex that grant exclusive access to a group of members.

The crate::lock::Mutex is prone to deadlock when using on a multiple struct fields like this:

use crate::lock::Mutex;

pub struct Foo {
    field1: Mutex<()>,
    field2: Mutex<()>,
}

The order to acquire the lock must be the same everywhere otherwise the deadlock is possible. Maintaining the lock order manually are cumbersome task so we introduce this type to handle this instead.

How this type are working is simple. Any locks on any member will lock the same mutex in the group, which mean there are only one mutex in the group. It have the same effect as the following code:

use crate::lock::Mutex;

pub struct Foo {
    data: Mutex<Data>,
}

struct Data {
    field1: (),
    field2: (),
}

The bonus point of this type is it will allow recursive lock for read-only access so you will never end up deadlock yourself. It will panic if you try to acquire write access while the readers are still active the same as core::cell::RefCell.

Fields

group: Arc<GutexGroup>

active: UnsafeCell<usize>

value: UnsafeCell<T>

Implementations

impl<T> Gutex<T>

pub fn read(&self) -> GutexRead<'_, T>

Locks this Gutex with read-only access.

Multiple read-only accesses can be taken out at the same time.

Panics

If there are an active write access to this Gutex.

pub fn write(&self) -> GutexWrite<'_, T>

Panics

If there are any active reader or writer.

Trait Implementations

impl<T: Send> Send for Gutex<T>

impl<T: Send> Sync for Gutex<T>