Struct rccell::RcCell [−][src]
pub struct RcCell<T>(_);
Expand description
Wrapper for Rc<RefCell<T>>
.
Implementations
Similar to Rc::try_unwrap.
Returns the inner value if the RefCell
has only one strong reference.
Otherwise, it returns an Err
with the same RefCell
that was passed in.
Note that this function success even if there are multiple weak references.
Examples
use rccell::RcCell;
let x = RcCell::new(1);
assert_eq!(RcCell::try_unwrap(x), Ok(1));
let x = RcCell::new(2);
let _y = RcCell::clone(&x);
assert!(RcCell::try_unwrap(x).is_err());
Returns the inner value if the RefCell
has only one strong reference. Otherwise, it panics.
Note that this function success even if there are multiple weak references.
Examples
use rccell::RcCell;
let x = RcCell::new(1);
assert_eq!(RcCell::unwrap(x), 1);
let x = RcCell::new(2);
let _y = RcCell::clone(&x);
// assert_eq!(RcCell::unwrap(x), 2); // This will panic, as there are two RcCells
Similar to Rc::downgrade. Creates a new WeakCell pointer to this allocation.
Examples
use rccell::RcCell;
let x = RcCell::new(1);
let weak_five = x.downgrade();
Similar to Rc::weak_count. Gets the number of WeakCell pointers to this allocation.
Examples
use rccell::RcCell;
let x = RcCell::new(1);
let weak_five = x.downgrade();
assert_eq!(RcCell::weak_count(&x), 1);
Similar to Rc::strong_count. Gets the number of strong (RcCell) pointers to this allocation.
Examples
use rccell::RcCell;
let x = RcCell::new(1);
let _y = x.clone();
assert_eq!(RcCell::strong_count(&x), 2);
Similar to Rc::ptr_eq.
Returns true
if two RcCell
s point to the same allocation.
Examples
use rccell::RcCell;
let x = RcCell::new(1);
let xx = x.clone();
let y = RcCell::new(1);
assert!(RcCell::ptr_eq(&x, &xx));
assert!(!RcCell::ptr_eq(&x, &y));
Similar to RefCell::try_borrow.
Returns a Ref to the inner value if there is no RefMut pointing to the same allocation.
Otherwise, it returns a BorrowError
.
Examples
use rccell::RcCell;
let x = RcCell::new(1);
let x_ref = x.try_borrow();
assert!(x_ref.is_ok());
Similar to RefCell::try_borrow_mut.
Returns a RefMut to the inner value if there is no RefMut nor Ref pointing to the same allocation.
Otherwise, it returns a BorrowMutError
.
Examples
use rccell::RcCell;
let x = RcCell::new(1);
let mut x_ref = x.try_borrow_mut();
assert!(x_ref.is_ok());
Similar to RefCell::borrow. Returns a Ref to the inner value if there is no RefMut pointing to the same allocation. Otherwise, it panics.
Examples
use rccell::RcCell;
let x = RcCell::new(1);
let x_ref = x.borrow();
Similar to RefCell::borrow_mut. Returns a RefMut to the inner value if there is no RefMut nor Ref pointing to the same allocation. Otherwise, it panics.
Examples
use rccell::RcCell;
let x = RcCell::new(1);
let x_ref = x.borrow_mut();
Methods from Deref<Target = RefCell<T>>
Replaces the wrapped value with a new one, returning the old value, without deinitializing either one.
This function corresponds to std::mem::replace
.
Panics
Panics if the value is currently borrowed.
Examples
use std::cell::RefCell;
let cell = RefCell::new(5);
let old_value = cell.replace(6);
assert_eq!(old_value, 5);
assert_eq!(cell, RefCell::new(6));
Replaces the wrapped value with a new one computed from f
, returning
the old value, without deinitializing either one.
Panics
Panics if the value is currently borrowed.
Examples
use std::cell::RefCell;
let cell = RefCell::new(5);
let old_value = cell.replace_with(|&mut old| old + 1);
assert_eq!(old_value, 5);
assert_eq!(cell, RefCell::new(6));
Swaps the wrapped value of self
with the wrapped value of other
,
without deinitializing either one.
This function corresponds to std::mem::swap
.
Panics
Panics if the value in either RefCell
is currently borrowed.
Examples
use std::cell::RefCell;
let c = RefCell::new(5);
let d = RefCell::new(6);
c.swap(&d);
assert_eq!(c, RefCell::new(6));
assert_eq!(d, RefCell::new(5));
Immutably borrows the wrapped value.
The borrow lasts until the returned Ref
exits scope. Multiple
immutable borrows can be taken out at the same time.
Panics
Panics if the value is currently mutably borrowed. For a non-panicking variant, use
try_borrow
.
Examples
use std::cell::RefCell;
let c = RefCell::new(5);
let borrowed_five = c.borrow();
let borrowed_five2 = c.borrow();
An example of panic:
use std::cell::RefCell;
let c = RefCell::new(5);
let m = c.borrow_mut();
let b = c.borrow(); // this causes a panic
Immutably borrows the wrapped value, returning an error if the value is currently mutably borrowed.
The borrow lasts until the returned Ref
exits scope. Multiple immutable borrows can be
taken out at the same time.
This is the non-panicking variant of borrow
.
Examples
use std::cell::RefCell;
let c = RefCell::new(5);
{
let m = c.borrow_mut();
assert!(c.try_borrow().is_err());
}
{
let m = c.borrow();
assert!(c.try_borrow().is_ok());
}
Mutably borrows the wrapped value.
The borrow lasts until the returned RefMut
or all RefMut
s derived
from it exit scope. The value cannot be borrowed while this borrow is
active.
Panics
Panics if the value is currently borrowed. For a non-panicking variant, use
try_borrow_mut
.
Examples
use std::cell::RefCell;
let c = RefCell::new("hello".to_owned());
*c.borrow_mut() = "bonjour".to_owned();
assert_eq!(&*c.borrow(), "bonjour");
An example of panic:
use std::cell::RefCell;
let c = RefCell::new(5);
let m = c.borrow();
let b = c.borrow_mut(); // this causes a panic
Mutably borrows the wrapped value, returning an error if the value is currently borrowed.
The borrow lasts until the returned RefMut
or all RefMut
s derived
from it exit scope. The value cannot be borrowed while this borrow is
active.
This is the non-panicking variant of borrow_mut
.
Examples
use std::cell::RefCell;
let c = RefCell::new(5);
{
let m = c.borrow();
assert!(c.try_borrow_mut().is_err());
}
assert!(c.try_borrow_mut().is_ok());
Returns a raw pointer to the underlying data in this cell.
Examples
use std::cell::RefCell;
let c = RefCell::new(5);
let ptr = c.as_ptr();
Immutably borrows the wrapped value, returning an error if the value is currently mutably borrowed.
Safety
Unlike RefCell::borrow
, this method is unsafe because it does not
return a Ref
, thus leaving the borrow flag untouched. Mutably
borrowing the RefCell
while the reference returned by this method
is alive is undefined behaviour.
Examples
use std::cell::RefCell;
let c = RefCell::new(5);
{
let m = c.borrow_mut();
assert!(unsafe { c.try_borrow_unguarded() }.is_err());
}
{
let m = c.borrow();
assert!(unsafe { c.try_borrow_unguarded() }.is_ok());
}
Trait Implementations
RefCell<T>
does not implement Deref
, and borrowing its inner value can cause a lot of panic errors.
Therefore, Deref::deref
will return a reference to the inner RefCell<T>
.
RefCell<T>
does not implement PartialEq
, and borrowing its inner value can cause a lot of panic errors.
Therefore, Hash
will only use the value of the Rc
pointer inside RefCell<T>
.
RefCell<T>
does not implement PartialEq
, and borrowing its inner value can cause a lot of panic errors.
Therefore, PartialEq
will check that two RefCell<T>
point to the exact same allocation.
Auto Trait Implementations
impl<T> !RefUnwindSafe for RcCell<T>
impl<T> !UnwindSafe for RcCell<T>
Blanket Implementations
Mutably borrows from an owned value. Read more