| #[macro_use] |
| extern crate rental; |
| |
| |
| pub struct Foo { |
| i: i32, |
| } |
| |
| pub struct Bar<'a> { |
| foo: &'a Foo, |
| } |
| |
| pub struct Baz<'a: 'b, 'b> { |
| bar: &'b Bar<'a> |
| } |
| |
| pub struct Qux<'a: 'b, 'b: 'c, 'c> { |
| baz: &'c Baz<'a, 'b> |
| } |
| |
| pub struct Xyzzy<'a: 'b, 'b: 'c, 'c: 'd, 'd> { |
| qux: &'d Qux<'a, 'b, 'c> |
| } |
| |
| |
| impl Foo { |
| pub fn borrow<'a>(&'a self) -> Bar<'a> { 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) -> Baz<'a, 'b> { Baz { bar: self } } |
| pub fn try_borrow<'b>(&'b self) -> Result<Baz<'a, 'b>, ()> { Ok(Baz { bar: self }) } |
| pub fn fail_borrow<'b>(&'b self) -> Result<Baz<'a, 'b>, ()> { Err(()) } |
| } |
| |
| impl<'a: 'b, 'b> Baz<'a, 'b> { |
| pub fn borrow<'c>(&'c self) -> Qux<'a, 'b, 'c> { Qux { baz: self } } |
| pub fn try_borrow<'c>(&'c self) -> Result<Qux<'a, 'b, 'c>, ()> { Ok(Qux { baz: self }) } |
| pub fn fail_borrow<'c>(&'c self) -> Result<Qux<'a, 'b, 'c>, ()> { Err(()) } |
| } |
| |
| impl<'a: 'b, 'b: 'c, 'c> Qux<'a, 'b, 'c> { |
| pub fn borrow<'d>(&'d self) -> Xyzzy<'a, 'b, 'c, 'd> { Xyzzy { qux: self } } |
| pub fn try_borrow<'d>(&'d self) -> Result<Xyzzy<'a, 'b, 'c, 'd>, ()> { Ok(Xyzzy { qux: self }) } |
| pub fn fail_borrow<'d>(&'d self) -> Result<Xyzzy<'a, 'b, 'c, 'd>, ()> { Err(()) } |
| } |
| |
| |
| rental! { |
| mod rentals { |
| use super::*; |
| |
| #[rental] |
| pub struct ComplexRent { |
| foo: Box<Foo>, |
| bar: Box<Bar<'foo>>, |
| baz: Box<Baz<'foo, 'bar>>, |
| qux: Box<Qux<'foo, 'bar, 'baz>>, |
| xyzzy: Xyzzy<'foo, 'bar, 'baz, 'qux>, |
| } |
| } |
| } |
| |
| |
| #[test] |
| fn new() { |
| let foo = Foo { i: 5 }; |
| let _ = rentals::ComplexRent::new( |
| Box::new(foo), |
| |foo| Box::new(foo.borrow()), |
| |bar, _| Box::new(bar.borrow()), |
| |baz, _, _| Box::new(baz.borrow()), |
| |qux, _, _, _| qux.borrow() |
| ); |
| |
| let foo = Foo { i: 5 }; |
| let cr = rentals::ComplexRent::try_new( |
| Box::new(foo), |
| |foo| foo.try_borrow().map(|bar| Box::new(bar)), |
| |bar, _| bar.try_borrow().map(|baz| Box::new(baz)), |
| |baz, _, _| baz.try_borrow().map(|qux| Box::new(qux)), |
| |qux, _, _, _| qux.try_borrow() |
| ); |
| assert!(cr.is_ok()); |
| |
| let foo = Foo { i: 5 }; |
| let cr = rentals::ComplexRent::try_new( |
| Box::new(foo), |
| |foo| foo.try_borrow().map(|bar| Box::new(bar)), |
| |bar, _| bar.try_borrow().map(|baz| Box::new(baz)), |
| |baz, _, _| baz.try_borrow().map(|qux| Box::new(qux)), |
| |qux, _, _, _| qux.fail_borrow() |
| ); |
| assert!(cr.is_err()); |
| } |
| |
| |
| #[test] |
| fn read() { |
| let foo = Foo { i: 5 }; |
| let cr = rentals::ComplexRent::new( |
| Box::new(foo), |
| |foo| Box::new(foo.borrow()), |
| |bar, _| Box::new(bar.borrow()), |
| |baz, _, _| Box::new(baz.borrow()), |
| |qux, _, _, _| qux.borrow() |
| ); |
| let i = cr.rent(|xyzzy| xyzzy.qux.baz.bar.foo.i); |
| assert_eq!(i, 5); |
| |
| let iref = cr.ref_rent(|xyzzy| &xyzzy.qux.baz.bar.foo.i); |
| assert_eq!(*iref, 5); |
| } |