bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

Strip down Cell functionality

Browse source
This commit is contained in:
Steven Fackler 2013-11-16 13:26:15 -08:00
parent 8a26266f65
commit 5759f2fc57
4 changed files with 24 additions and 84 deletions
Download patch file Download diff file Expand all files Collapse all files

62
src/libstd/cell.rs
View file

@ -8,12 +8,11 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! A mutable, nullable memory location
//! Runtime move semantics
#[missing_doc];
use cast::transmute_mut;
use unstable::finally::Finally;
use prelude::*;
/*
@ -35,11 +34,6 @@ impl<T> Cell<T> {
Cell { value: Some(value) }
}
/// Creates a new empty cell with no value inside.
pub fn new_empty() -> Cell<T> {
Cell { value: None }
}
/// Yields the value, failing if the cell is empty.
pub fn take(&self) -> T {
let this = unsafe { transmute_mut(self) };
@ -56,34 +50,10 @@ impl<T> Cell<T> {
this.value.take()
}
/// Returns the value, failing if the cell is full.
pub fn put_back(&self, value: T) {
let this = unsafe { transmute_mut(self) };
if !this.is_empty() {
fail!("attempt to put a value back into a full cell");
}
this.value = Some(value);
}
/// Returns true if the cell is empty and false if the cell is full.
pub fn is_empty(&self) -> bool {
self.value.is_none()
}
/// Calls a closure with a reference to the value.
pub fn with_ref<R>(&self, op: |v: &T| -> R) -> R {
do self.with_mut_ref |ptr| { op(ptr) }
}
/// Calls a closure with a mutable reference to the value.
pub fn with_mut_ref<R>(&self, op: |v: &mut T| -> R) -> R {
let mut v = Some(self.take());
do (|| {
op(v.get_mut_ref())
}).finally {
self.put_back(v.take_unwrap());
}
}
}
#[test]
@ -93,38 +63,12 @@ fn test_basic() {
let value = value_cell.take();
assert!(value == ~10);
assert!(value_cell.is_empty());
value_cell.put_back(value);
assert!(!value_cell.is_empty());
}
#[test]
#[should_fail]
fn test_take_empty() {
let value_cell: Cell<~int> = Cell::new_empty();
let value_cell: Cell<~int> = Cell::new(~0);
value_cell.take();
value_cell.take();
}
#[test]
#[should_fail]
fn test_put_back_non_empty() {
let value_cell = Cell::new(~10);
value_cell.put_back(~20);
}
#[test]
fn test_with_ref() {
let good = 6;
let c = Cell::new(~[1, 2, 3, 4, 5, 6]);
let l = do c.with_ref() |v| { v.len() };
assert_eq!(l, good);
}
#[test]
fn test_with_mut_ref() {
let good = ~[1, 2, 3];
let v = ~[1, 2];
let c = Cell::new(v);
do c.with_mut_ref() |v| { v.push(3); }
let v = c.take();
assert_eq!(v, good);
}