47 lines
1007 B
Rust
47 lines
1007 B
Rust
// TODO: Use `Rc` and `RefCell` to implement `DropTracker<T>`, a wrapper around a value of type `T`
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// that increments a shared `usize` counter every time the wrapped value is dropped.
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use std::cell::RefCell;
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use std::rc::Rc;
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pub struct DropTracker<T> {
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value: T,
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counter: todo!(),
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}
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impl<T> DropTracker<T> {
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pub fn new(value: T, counter: todo!()) -> Self {
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Self { value, counter }
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}
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}
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impl<T> Drop for DropTracker<T> {
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fn drop(&mut self) {
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todo!()
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn it_works() {
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let counter = Rc::new(RefCell::new(0));
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let _ = DropTracker::new((), Rc::clone(&counter));
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assert_eq!(*counter.borrow(), 1);
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}
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#[test]
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fn multiple() {
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let counter = Rc::new(RefCell::new(0));
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{
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let a = DropTracker::new(5, Rc::clone(&counter));
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let b = DropTracker::new(6, Rc::clone(&counter));
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}
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assert_eq!(*counter.borrow(), 2);
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}
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}
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