Struct incr::RcIncr

pub struct RcIncr(_);

The Rc<Cell<_>> backed storage of RcIncr provides flexibility in situations where the counter must be shared among several disparate objects/contexts while retaining consistentcy between all the references of the count. RcIncr is not threadsafe, and even in single-threaded code Rc<Cell<T>> has some tricky edge cases, for instance if a Cell<T> is used as the key to a hash map and the interior value mutated (fair warning).

Examples

use incr::RcIncr;
let mut last = RcIncr::default();
assert_eq!(last.is_new(1), true);
let mut xs = Vec::new();
for i in 2..5 {
    xs.push(last.clone());
    xs.last().unwrap().is_new(i);
}
assert_eq!(last.get(), 4);
for x in &xs {
    assert_eq!(x.get(), 4);
}

Methods

impl RcIncr

pub fn is_new(&self, val: u64) -> bool

Returns true if val is greater than the highest previously observed value. If val is a new maximum, it is stored in self for checks against future values subsequent calls Self::get(&self) will return val until a new max is observed.

pub fn get(&self) -> u64

Returns the current maximum.

Trait Implementations

impl Default for RcIncr

fn default() -> RcIncr

Returns the "default value" for a type.

impl Clone for RcIncr

fn clone(&self) -> RcIncr

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.