1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87

/***********************************************************************************************************************
 * Copyright (c) 2020 by the authors
 *
 * Author: André Borrmann <pspwizard@gmx.de>
 * License: Apache License 2.0 / MIT
 **********************************************************************************************************************/
#![doc(html_root_url = "https://docs.rs/ruspiro-lock/0.4.2")]
#![cfg_attr(not(any(test, doctest)), no_std)]
#![feature(llvm_asm)]

//! # Atomic locks for Raspberry Pi baremetal systems
//!
//! This crate provides different kinds of locks and access guards to secure data access across cores and/or threads.
//! Those locks are *Spinlock*, *Semaphore*, *Mutex* and *RWLock*. The * Semaphore*, *Mutex* and *RWLock* are available
//! as `async` version as well to allow them to work in a *non blocking* fashion as required by `async` code.
//!
//! ## Usage Hint:
//! As the locks depend on low level atomics they do only work on the Raspberry Pi if the MMU is properly configured.
//! Otherwise using either of the lock functions will hang the core it has been used on.
//!
//! ## Features
//!
//! Feature | Usage
//! --------|--------
//! async_locks | allows usage of the `async` lock versions.
//!
//!
//! To share those locking primitives accross the Rasperry Pi cores they should be wrapped in an ``Arc``.
//!
//! # Usage
//!
//! ## Spinlock
//! ```
//! use ruspiro_lock::sync::Spinlock;
//!
//! fn main() {
//!     let spin = Spinlock::new();
//!     spin.aquire();
//!     // following code is only executed if the lock could be aquired, the executing core pause till then
//!     let _ = 10 + 3;
//!     spin.release();
//! }
//! ```
//!
//! ## Semaphore
//! ```
//! use ruspiro_lock::sync::Semaphore;
//!
//! fn main() {
//!     let sema  = Semaphore::new(1);
//!     if sema.try_down().is_ok() {
//!         // we gained access to the semaphore, do something
//!         let _ = 20 /4;
//!         sema.up();
//!     }
//! }
//! ```
//!
//! ## Mutex
//! ```
//! use ruspiro_lock::sync::Mutex;
//!
//! fn main() {
//!     let mutex = Mutex::new(0u32);
//!     if let Some(mut data) = mutex.try_lock() {
//!         *data = 20;
//!     }
//!     // once the data goes ot of scope the lock will be released
//!     if let Some(data) = mutex.try_lock() {
//!         println!("data: {}", *data);
//!     
//!         // another lock should fail inside this scope
//!         assert!(mutex.try_lock().is_none());
//!     }
//!     
//!     // a blocking lock on the data will block the current execution until the lock get's available
//!     let mut data = mutex.lock();
//!     *data = 12;
//! }
//! ```

// re-export the sync lock types, always at root level and witin the sync module
pub mod sync;
pub use sync::*;

#[cfg(any(feature = "async_locks", doc))]
pub mod r#async;