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

//! Runtime managed mutable borrowing from a map.
//!
//! This library provides a map that allows mutable borrows to different entries
//! at the same time.
//!
//! This implementation is extracted and slightly modified from [`shred`].
//!
//! ## Usage
//!
//! Add the following to `Cargo.toml`
//!
//! ```toml
//! rt_map = "0.2.0"
//! ```
//!
//! In code:
//!
//! ```rust
//! use rt_map::RtMap;
//!
//! struct A(u32);
//!
//! let mut rt_map = RtMap::new();
//!
//! rt_map.insert('a', A(1));
//! rt_map.insert('b', A(2));
//!
//! // We can validly have two mutable borrows from the `RtMap` map!
//! let mut a = rt_map.borrow_mut(&'a');
//! let mut b = rt_map.borrow_mut(&'b');
//! a.0 = 2;
//! b.0 = 3;
//!
//! // We need to explicitly drop the A and B borrows, because they are runtime
//! // managed borrows, and rustc doesn't know to drop them before the immutable
//! // borrows after this.
//! drop(a);
//! drop(b);
//!
//! // Multiple immutable borrows to the same value are valid.
//! let a_0 = rt_map.borrow(&'a');
//! let _a_1 = rt_map.borrow(&'a');
//! let b = rt_map.borrow(&'b');
//!
//! println!("A: {}", a_0.0);
//! println!("B: {}", b.0);
//!
//! // Trying to mutably borrow a value that is already borrowed (immutably
//! // or mutably) returns `None`.
//! let a_try_borrow_mut = rt_map.try_borrow_mut(&'a');
//! let exists = if a_try_borrow_mut.is_some() {
//!     "Some(..)"
//! } else {
//!     "None"
//! };
//! println!("a_try_borrow_mut: {}", exists); // prints "None"
//! ```
//!
//! ## See Also
//!
//! * [`anymap`]: Map of any type, without multiple mutable borrows.
//! * [`resman`]: Map of any type, with runtime managed borrowing.
//! * [`shred`]: Contains `RtMap` type, plus a task dispatcher.
//!
//! [`anymap`]: https://github.com/chris-morgan/anymap
//! [`resman`]: https://github.com/azriel91/resman
//! [`shred`]: https://github.com/amethyst/shred

pub use crate::{
    cell::Cell, cell_ref::CellRef, cell_ref_mut::CellRefMut, entry::Entry, r#ref::Ref,
    ref_mut::RefMut, rt_map::RtMap,
};

mod cell;
mod cell_ref;
mod cell_ref_mut;
mod entry;
mod r#ref;
mod ref_mut;
mod rt_map;