1 unstable release
0.1.0 | Sep 28, 2023 |
---|
#877 in WebAssembly
10KB
190 lines
retentive-lender
This crate provides retentive_lender::Lender
which wraps Rc<RefCell<T>>
for the interior mutability pattern. It also keeps the name of the borrower until the value is dropped, and shows the borrower information when it violates the Rust's borrow rule.
Install
cargo add retentive-lender
Usage
use retentive_lender::Lender;
{
let data = Lender::new(1);
let borrow1 = data.borrow("borrow 1")?;
let borrow2 = data.borrow_mut("borrow 2");
assert!(borrow2, Err(r#"Failed to borrow mutable reference. Currently borrowed by: ["borrow 1"]"#.to_string()));
}
{
let data = Lender::new(1);
let borrow1 = data.borrow_mut("borrow 1")?;
let borrow2 = data.borrow("borrow 2");
assert!(borrow2, Err(r#"Failed to borrow immutable reference. Currently borrowed by: ["borrow 1 (mut)"]"#.to_string()));
}
{
let data = Lender::new(1);
let borrow1 = data.borrow("borrow 1")?;
let borrow2 = data.borrow("borrow 2")?;
let borrow3 = data.borrow_mut("borrow 3");
assert!(borrow3, Err(r#"Failed to borrow mutable reference. Currently borrowed by: ["borrow 1", "borrow 2"]"#.to_string()));
}
Comparison with debug_cell
and accountable-refcell
While developing this library I found a similary library named debug_cell
accountable-refcell
.
They are thin wrappers of RefCell
which store the backtraces of the borrow calls and shows the backtraces on BorrowError / BorrowMutError.
While these libraries are pretty useful, they only work when RUST_BACKTRACE is defined. This means we have to configure the build to include debug symbols, which is troublesome in some use cases, especially on WebAssembly.
Also, retentive-lender
only provides limited APIs and the users cannot access the RefCell
directly, so it will never panic.
LICENSE
MIT