1 // Copyright 2018 The Chromium OS Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 //! Sync primitive types whose methods panic rather than returning error in case of poison.
6 //!
7 //! The Mutex/Condvar type in this crates wraps the standard library versions and mirrors the same
8 //! methods, except that they panic where the standard library would return an Error. This API
9 //! codifies our error handling strategy around poisoned mutexes in crosvm.
10 //!
11 //! - Crosvm releases are built with panic=abort so poisoning never occurs. A panic while a mutex is
12 //!   held (or ever) takes down the entire process. Thus we would like for code not to have to
13 //!   consider the possibility of poison.
14 //!
15 //! - We could ask developers to always write `.lock().unwrap()` on a standard library mutex.
16 //!   However, we would like to stigmatize the use of unwrap. It is confusing to permit unwrap but
17 //!   only on mutex lock results. During code review it may not always be obvious whether a
18 //!   particular unwrap is unwrapping a mutex lock result or a different error that should be
19 //!   handled in a more principled way.
20 //!
21 //! Developers should feel free to use types defined in this crate anywhere in crosvm that they
22 //! would otherwise be using the corresponding types in std::sync.
23 
24 mod condvar;
25 mod mutex;
26 
27 pub use crate::condvar::Condvar;
28 pub use crate::mutex::{Mutex, WouldBlock};
29