| #[macro_use] |
| extern crate rental; |
| |
| |
| pub struct Foo { |
| pub i: i32, |
| } |
| |
| pub struct Bar<'a> { |
| pub foo: &'a Foo, |
| } |
| |
| pub struct Qux<'a: 'b, 'b> { |
| pub bar: &'b Bar<'a>, |
| } |
| |
| |
| impl Foo { |
| pub fn borrow(&self) -> Bar { Bar { foo: self } } |
| pub fn try_borrow<'a>(&'a self) -> Result<Bar<'a>, ()> { Ok(Bar { foo: self }) } |
| pub fn fail_borrow<'a>(&'a self) -> Result<Bar<'a>, ()> { Err(()) } |
| } |
| |
| impl<'a> Bar<'a> { |
| pub fn borrow<'b>(&'b self) -> Qux<'a, 'b> { Qux { bar: self } } |
| pub fn try_borrow<'b>(&'b self) -> Result<Qux<'a, 'b>, ()> { Ok(Qux { bar: self }) } |
| pub fn fail_borrow<'b>(&'b self) -> Result<Qux<'a, 'b>, ()> { Err(()) } |
| } |
| |
| |
| rental! { |
| pub mod rentals { |
| use super::*; |
| |
| #[rental] |
| pub struct Sub { |
| foo: Box<Foo>, |
| bar: Bar<'foo>, |
| } |
| |
| #[rental] |
| pub struct Rent { |
| #[subrental = 2] |
| sub: Box<Sub>, |
| qux: Qux<'sub_0, 'sub_1>, |
| } |
| |
| #[rental] |
| pub struct BorrowSub<'f> { |
| foo: &'f Foo, |
| bar: Bar<'foo>, |
| } |
| |
| #[rental] |
| pub struct TailRent { |
| foo: Box<Foo>, |
| #[subrental = 2] |
| sub: Box<BorrowSub<'foo>>, |
| iref: &'sub_1 i32, |
| } |
| } |
| } |
| |
| |
| #[test] |
| fn new() { |
| let foo = Foo { i: 5 }; |
| let sub = rentals::Sub::new(Box::new(foo), |foo| foo.borrow()); |
| let _ = rentals::Rent::new(Box::new(sub), |sub| sub.bar.borrow()); |
| |
| let foo = Foo { i: 5 }; |
| let sub = rentals::Sub::new(Box::new(foo), |foo| foo.borrow()); |
| let rent = rentals::Rent::try_new(Box::new(sub), |sub| sub.bar.try_borrow()); |
| assert!(rent.is_ok()); |
| |
| let foo = Foo { i: 5 }; |
| let sub = rentals::Sub::new(Box::new(foo), |foo| foo.borrow()); |
| let rent = rentals::Rent::try_new(Box::new(sub), |sub| sub.bar.fail_borrow()); |
| assert!(rent.is_err()); |
| } |
| |
| |
| #[test] |
| fn read() { |
| let foo = Foo { i: 5 }; |
| let sub = rentals::Sub::new(Box::new(foo), |foo| foo.borrow()); |
| let _ = rentals::Rent::new(Box::new(sub), |sub| sub.bar.borrow()); |
| } |