Move mutable::Mut to cell::RefCell

This commit is contained in:
Steven Fackler 2013-11-21 21:30:34 -08:00
parent c6ca9abcc6
commit bdfaf04bd5
11 changed files with 335 additions and 350 deletions

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@ -8,12 +8,14 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! Runtime move semantics
//! Types dealing with dynamic mutability
#[missing_doc];
use cast::transmute_mut;
use prelude::*;
use cast;
use util::NonCopyable;
/*
A dynamic, mutable location.
@ -36,7 +38,7 @@ impl<T> Cell<T> {
/// Yields the value, failing if the cell is empty.
pub fn take(&self) -> T {
let this = unsafe { transmute_mut(self) };
let this = unsafe { cast::transmute_mut(self) };
if this.is_empty() {
fail!("attempt to take an empty cell");
}
@ -46,7 +48,7 @@ impl<T> Cell<T> {
/// Yields the value if the cell is full, or `None` if it is empty.
pub fn take_opt(&self) -> Option<T> {
let this = unsafe { transmute_mut(self) };
let this = unsafe { cast::transmute_mut(self) };
this.value.take()
}
@ -72,3 +74,295 @@ fn test_take_empty() {
value_cell.take();
value_cell.take();
}
/// A mutable memory location with dynamically checked borrow rules
#[no_freeze]
pub struct RefCell<T> {
priv value: T,
priv borrow: BorrowFlag,
priv nc: NonCopyable
}
// Values [1, MAX-1] represent the number of `Ref` active
// (will not outgrow its range since `uint` is the size of the address space)
type BorrowFlag = uint;
static UNUSED: BorrowFlag = 0;
static WRITING: BorrowFlag = -1;
impl<T> RefCell<T> {
/// Create a new `RefCell` containing `value`
pub fn new(value: T) -> RefCell<T> {
RefCell {
value: value,
borrow: UNUSED,
nc: NonCopyable
}
}
/// Consumes the `RefCell`, returning the wrapped value.
pub fn unwrap(self) -> T {
assert!(self.borrow == UNUSED);
self.value
}
unsafe fn as_mut<'a>(&'a self) -> &'a mut RefCell<T> {
cast::transmute_mut(self)
}
/// Attempts to immutably borrow the wrapped value.
///
/// The borrow lasts until the returned `Ref` exits scope. Multiple
/// immutable borrows can be taken out at the same time.
///
/// Returns `None` if the value is currently mutably borrowed.
pub fn try_borrow<'a>(&'a self) -> Option<Ref<'a, T>> {
match self.borrow {
WRITING => None,
_ => {
unsafe { self.as_mut().borrow += 1; }
Some(Ref { parent: self })
}
}
}
/// 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.
///
/// # Failure
///
/// Fails if the value is currently mutably borrowed.
pub fn borrow<'a>(&'a self) -> Ref<'a, T> {
match self.try_borrow() {
Some(ptr) => ptr,
None => fail!("RefCell<T> already mutably borrowed")
}
}
/// Mutably borrows the wrapped value.
///
/// The borrow lasts untile the returned `RefMut` exits scope. The value
/// cannot be borrowed while this borrow is active.
///
/// Returns `None` if the value is currently borrowed.
pub fn try_borrow_mut<'a>(&'a self) -> Option<RefMut<'a, T>> {
match self.borrow {
UNUSED => unsafe {
let mut_self = self.as_mut();
mut_self.borrow = WRITING;
Some(RefMut { parent: mut_self })
},
_ => None
}
}
/// Mutably borrows the wrapped value.
///
/// The borrow lasts untile the returned `RefMut` exits scope. The value
/// cannot be borrowed while this borrow is active.
///
/// # Failure
///
/// Fails if the value is currently borrowed.
pub fn borrow_mut<'a>(&'a self) -> RefMut<'a, T> {
match self.try_borrow_mut() {
Some(ptr) => ptr,
None => fail!("RefCell<T> already borrowed")
}
}
/// Immutably borrows the wrapped value and applies `blk` to it.
///
/// # Failure
///
/// Fails if the value is currently mutably borrowed.
#[inline]
pub fn with<U>(&self, blk: |&T| -> U) -> U {
let ptr = self.borrow();
blk(ptr.get())
}
/// Mutably borrows the wrapped value and applies `blk` to it.
///
/// # Failure
///
/// Fails if the value is currently borrowed.
#[inline]
pub fn with_mut<U>(&self, blk: |&mut T| -> U) -> U {
let mut ptr = self.borrow_mut();
blk(ptr.get())
}
}
impl<T: Clone> Clone for RefCell<T> {
fn clone(&self) -> RefCell<T> {
let x = self.borrow();
RefCell::new(x.get().clone())
}
}
impl<T: DeepClone> DeepClone for RefCell<T> {
fn deep_clone(&self) -> RefCell<T> {
let x = self.borrow();
RefCell::new(x.get().deep_clone())
}
}
impl<T: Eq> Eq for RefCell<T> {
fn eq(&self, other: &RefCell<T>) -> bool {
let a = self.borrow();
let b = other.borrow();
a.get() == b.get()
}
}
/// Wraps a borrowed reference to a value in a `RefCell` box.
pub struct Ref<'box, T> {
priv parent: &'box RefCell<T>
}
#[unsafe_destructor]
impl<'box, T> Drop for Ref<'box, T> {
fn drop(&mut self) {
assert!(self.parent.borrow != WRITING && self.parent.borrow != UNUSED);
unsafe { self.parent.as_mut().borrow -= 1; }
}
}
impl<'box, T> Ref<'box, T> {
/// Retrieve an immutable reference to the stored value.
#[inline]
pub fn get<'a>(&'a self) -> &'a T {
&self.parent.value
}
}
/// Wraps a mutable borrowed reference to a value in a `RefCell` box.
pub struct RefMut<'box, T> {
priv parent: &'box mut RefCell<T>
}
#[unsafe_destructor]
impl<'box, T> Drop for RefMut<'box, T> {
fn drop(&mut self) {
assert!(self.parent.borrow == WRITING);
self.parent.borrow = UNUSED;
}
}
impl<'box, T> RefMut<'box, T> {
/// Retrieve a mutable reference to the stored value.
#[inline]
pub fn get<'a>(&'a mut self) -> &'a mut T {
&mut self.parent.value
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn double_imm_borrow() {
let x = RefCell::new(0);
let _b1 = x.borrow();
x.borrow();
}
#[test]
fn no_mut_then_imm_borrow() {
let x = RefCell::new(0);
let _b1 = x.borrow_mut();
assert!(x.try_borrow().is_none());
}
#[test]
fn no_imm_then_borrow_mut() {
let x = RefCell::new(0);
let _b1 = x.borrow();
assert!(x.try_borrow_mut().is_none());
}
#[test]
fn no_double_borrow_mut() {
let x = RefCell::new(0);
let _b1 = x.borrow_mut();
assert!(x.try_borrow_mut().is_none());
}
#[test]
fn imm_release_borrow_mut() {
let x = RefCell::new(0);
{
let _b1 = x.borrow();
}
x.borrow_mut();
}
#[test]
fn mut_release_borrow_mut() {
let x = RefCell::new(0);
{
let _b1 = x.borrow_mut();
}
x.borrow();
}
#[test]
fn double_borrow_single_release_no_borrow_mut() {
let x = RefCell::new(0);
let _b1 = x.borrow();
{
let _b2 = x.borrow();
}
assert!(x.try_borrow_mut().is_none());
}
#[test]
fn with_ok() {
let x = RefCell::new(0);
assert_eq!(1, x.with(|x| *x+1));
}
#[test]
#[should_fail]
fn mut_borrow_with() {
let x = RefCell::new(0);
let _b1 = x.borrow_mut();
x.with(|x| *x+1);
}
#[test]
fn borrow_with() {
let x = RefCell::new(0);
let _b1 = x.borrow();
assert_eq!(1, x.with(|x| *x+1));
}
#[test]
fn with_mut_ok() {
let x = RefCell::new(0);
x.with_mut(|x| *x += 1);
let b = x.borrow();
assert_eq!(1, *b.get());
}
#[test]
#[should_fail]
fn borrow_with_mut() {
let x = RefCell::new(0);
let _b = x.borrow();
x.with_mut(|x| *x += 1);
}
#[test]
#[should_fail]
fn discard_doesnt_unborrow() {
let x = RefCell::new(0);
let _b = x.borrow();
let _ = _b;
let _b = x.borrow_mut();
}
}

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@ -55,26 +55,26 @@ impl<T: DeepClone + Send + 'static> DeepClone for Gc<T> {
#[cfg(test)]
mod tests {
use super::*;
use cell::Cell;
use cell::RefCell;
#[test]
fn test_clone() {
let x = Gc::new(Cell::new(5));
let x = Gc::new(RefCell::new(5));
let y = x.clone();
do x.borrow().with_mut_ref |inner| {
do x.borrow().with_mut |inner| {
*inner = 20;
}
assert_eq!(y.borrow().take(), 20);
assert_eq!(y.borrow().with(|x| *x), 20);
}
#[test]
fn test_deep_clone() {
let x = Gc::new(Cell::new(5));
let x = Gc::new(RefCell::new(5));
let y = x.deep_clone();
do x.borrow().with_mut_ref |inner| {
do x.borrow().with_mut |inner| {
*inner = 20;
}
assert_eq!(y.borrow().take(), 5);
assert_eq!(y.borrow().with(|x| *x), 5);
}
#[test]

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@ -164,7 +164,6 @@ pub mod result;
pub mod either;
pub mod hashmap;
pub mod cell;
pub mod mutable;
pub mod trie;

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@ -1,307 +0,0 @@
// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! A mutable memory location with dynamically checked borrow rules
use prelude::*;
use cast;
use util::NonCopyable;
/// A mutable memory location with dynamically checked borrow rules
#[no_freeze]
pub struct Mut<T> {
priv value: T,
priv borrow: BorrowFlag,
priv nc: NonCopyable
}
// Values [1, MAX-1] represent the number of `Ref` active
// (will not outgrow its range since `uint` is the size of the address space)
type BorrowFlag = uint;
static UNUSED: BorrowFlag = 0;
static WRITING: BorrowFlag = -1;
impl<T> Mut<T> {
/// Create a new `Mut` containing `value`
pub fn new(value: T) -> Mut<T> {
Mut {
value: value,
borrow: UNUSED,
nc: NonCopyable
}
}
/// Consumes the `Mut`, returning the wrapped value.
pub fn unwrap(self) -> T {
assert!(self.borrow == UNUSED);
self.value
}
unsafe fn as_mut<'a>(&'a self) -> &'a mut Mut<T> {
cast::transmute_mut(self)
}
/// Attempts to immutably borrow the wrapped value.
///
/// The borrow lasts until the returned `Ref` exits scope. Multiple
/// immutable borrows can be taken out at the same time.
///
/// Returns `None` if the value is currently mutably borrowed.
pub fn try_borrow<'a>(&'a self) -> Option<Ref<'a, T>> {
match self.borrow {
WRITING => None,
_ => {
unsafe { self.as_mut().borrow += 1; }
Some(Ref { parent: self })
}
}
}
/// 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.
///
/// # Failure
///
/// Fails if the value is currently mutably borrowed.
pub fn borrow<'a>(&'a self) -> Ref<'a, T> {
match self.try_borrow() {
Some(ptr) => ptr,
None => fail!("Mut<T> already mutably borrowed")
}
}
/// Mutably borrows the wrapped value.
///
/// The borrow lasts untile the returned `RefMut` exits scope. The value
/// cannot be borrowed while this borrow is active.
///
/// Returns `None` if the value is currently borrowed.
pub fn try_borrow_mut<'a>(&'a self) -> Option<RefMut<'a, T>> {
match self.borrow {
UNUSED => unsafe {
let mut_self = self.as_mut();
mut_self.borrow = WRITING;
Some(RefMut { parent: mut_self })
},
_ => None
}
}
/// Mutably borrows the wrapped value.
///
/// The borrow lasts untile the returned `RefMut` exits scope. The value
/// cannot be borrowed while this borrow is active.
///
/// # Failure
///
/// Fails if the value is currently borrowed.
pub fn borrow_mut<'a>(&'a self) -> RefMut<'a, T> {
match self.try_borrow_mut() {
Some(ptr) => ptr,
None => fail!("Mut<T> already borrowed")
}
}
/// Immutably borrows the wrapped value and applies `blk` to it.
///
/// # Failure
///
/// Fails if the value is currently mutably borrowed.
#[inline]
pub fn with<U>(&self, blk: |&T| -> U) -> U {
let ptr = self.borrow();
blk(ptr.get())
}
/// Mutably borrows the wrapped value and applies `blk` to it.
///
/// # Failure
///
/// Fails if the value is currently borrowed.
#[inline]
pub fn with_mut<U>(&self, blk: |&mut T| -> U) -> U {
let mut ptr = self.borrow_mut();
blk(ptr.get())
}
}
impl<T: Clone> Clone for Mut<T> {
fn clone(&self) -> Mut<T> {
let x = self.borrow();
Mut::new(x.get().clone())
}
}
impl<T: DeepClone> DeepClone for Mut<T> {
fn deep_clone(&self) -> Mut<T> {
let x = self.borrow();
Mut::new(x.get().deep_clone())
}
}
impl<T: Eq> Eq for Mut<T> {
fn eq(&self, other: &Mut<T>) -> bool {
let a = self.borrow();
let b = other.borrow();
a.get() == b.get()
}
}
/// Wraps a borrowed reference to a value in a `Mut` box.
pub struct Ref<'box, T> {
priv parent: &'box Mut<T>
}
#[unsafe_destructor]
impl<'box, T> Drop for Ref<'box, T> {
fn drop(&mut self) {
assert!(self.parent.borrow != WRITING && self.parent.borrow != UNUSED);
unsafe { self.parent.as_mut().borrow -= 1; }
}
}
impl<'box, T> Ref<'box, T> {
/// Retrieve an immutable reference to the stored value.
#[inline]
pub fn get<'a>(&'a self) -> &'a T {
&self.parent.value
}
}
/// Wraps a mutable borrowed reference to a value in a `Mut` box.
pub struct RefMut<'box, T> {
priv parent: &'box mut Mut<T>
}
#[unsafe_destructor]
impl<'box, T> Drop for RefMut<'box, T> {
fn drop(&mut self) {
assert!(self.parent.borrow == WRITING);
self.parent.borrow = UNUSED;
}
}
impl<'box, T> RefMut<'box, T> {
/// Retrieve a mutable reference to the stored value.
#[inline]
pub fn get<'a>(&'a mut self) -> &'a mut T {
&mut self.parent.value
}
}
#[cfg(test)]
mod test {
use super::*;
#[test]
fn double_imm_borrow() {
let x = Mut::new(0);
let _b1 = x.borrow();
x.borrow();
}
#[test]
fn no_mut_then_imm_borrow() {
let x = Mut::new(0);
let _b1 = x.borrow_mut();
assert!(x.try_borrow().is_none());
}
#[test]
fn no_imm_then_borrow_mut() {
let x = Mut::new(0);
let _b1 = x.borrow();
assert!(x.try_borrow_mut().is_none());
}
#[test]
fn no_double_borrow_mut() {
let x = Mut::new(0);
let _b1 = x.borrow_mut();
assert!(x.try_borrow_mut().is_none());
}
#[test]
fn imm_release_borrow_mut() {
let x = Mut::new(0);
{
let _b1 = x.borrow();
}
x.borrow_mut();
}
#[test]
fn mut_release_borrow_mut() {
let x = Mut::new(0);
{
let _b1 = x.borrow_mut();
}
x.borrow();
}
#[test]
fn double_borrow_single_release_no_borrow_mut() {
let x = Mut::new(0);
let _b1 = x.borrow();
{
let _b2 = x.borrow();
}
assert!(x.try_borrow_mut().is_none());
}
#[test]
fn with_ok() {
let x = Mut::new(0);
assert_eq!(1, x.with(|x| *x+1));
}
#[test]
#[should_fail]
fn mut_borrow_with() {
let x = Mut::new(0);
let _b1 = x.borrow_mut();
x.with(|x| *x+1);
}
#[test]
fn borrow_with() {
let x = Mut::new(0);
let _b1 = x.borrow();
assert_eq!(1, x.with(|x| *x+1));
}
#[test]
fn with_mut_ok() {
let x = Mut::new(0);
x.with_mut(|x| *x += 1);
let b = x.borrow();
assert_eq!(1, *b.get());
}
#[test]
#[should_fail]
fn borrow_with_mut() {
let x = Mut::new(0);
let _b = x.borrow();
x.with_mut(|x| *x += 1);
}
#[test]
#[should_fail]
fn discard_doesnt_unborrow() {
let x = Mut::new(0);
let _b = x.borrow();
let _ = _b;
let _b = x.borrow_mut();
}
}

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@ -21,7 +21,7 @@ use unstable::intrinsics::transmute;
use ops::Drop;
use kinds::{Freeze, Send};
use clone::{Clone, DeepClone};
use mutable::Mut;
use cell::RefCell;
struct RcBox<T> {
value: T,
@ -55,10 +55,10 @@ impl<T: Send> Rc<T> {
}
}
impl<T: Freeze> Rc<Mut<T>> {
/// Construct a new reference-counted box from a `Mut`-wrapped `Freeze` value
impl<T: Freeze> Rc<RefCell<T>> {
/// Construct a new reference-counted box from a `RefCell`-wrapped `Freeze` value
#[inline]
pub fn from_mut(value: Mut<T>) -> Rc<Mut<T>> {
pub fn from_mut(value: RefCell<T>) -> Rc<RefCell<T>> {
unsafe {
Rc::new_unchecked(value)
}
@ -116,11 +116,11 @@ impl<T> Drop for Rc<T> {
#[cfg(test)]
mod test_rc {
use super::*;
use mutable::Mut;
use cell::RefCell;
#[test]
fn test_clone() {
let x = Rc::from_send(Mut::new(5));
let x = Rc::from_send(RefCell::new(5));
let y = x.clone();
do x.borrow().with_mut |inner| {
*inner = 20;
@ -130,7 +130,7 @@ mod test_rc {
#[test]
fn test_deep_clone() {
let x = Rc::from_send(Mut::new(5));
let x = Rc::from_send(RefCell::new(5));
let y = x.deep_clone();
do x.borrow().with_mut |inner| {
*inner = 20;
@ -161,6 +161,6 @@ mod test_rc {
#[test]
fn test_from_mut() {
let a = 10;
let _x = Rc::from_mut(Mut::new(&a));
let _x = Rc::from_mut(RefCell::new(&a));
}
}

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@ -25,10 +25,9 @@ use unstable::sync::UnsafeArc;
use util;
use util::Void;
use comm::{GenericChan, GenericSmartChan, GenericPort, Peekable, SendDeferred};
use cell::Cell;
use cell::{Cell, RefCell};
use clone::Clone;
use tuple::ImmutableTuple;
use mutable::Mut;
/// A combined refcount / BlockedTask-as-uint pointer.
///
@ -433,20 +432,20 @@ type StreamPortOne<T> = PortOne<StreamPayload<T>>;
/// A channel with unbounded size.
pub struct Chan<T> {
// FIXME #5372. Using Mut because we don't take &mut self
next: Mut<StreamChanOne<T>>
// FIXME #5372. Using RefCell because we don't take &mut self
next: RefCell<StreamChanOne<T>>
}
/// An port with unbounded size.
pub struct Port<T> {
// FIXME #5372. Using Mut because we don't take &mut self
next: Mut<Option<StreamPortOne<T>>>
// FIXME #5372. Using RefCell because we don't take &mut self
next: RefCell<Option<StreamPortOne<T>>>
}
pub fn stream<T: Send>() -> (Port<T>, Chan<T>) {
let (pone, cone) = oneshot();
let port = Port { next: Mut::new(Some(pone)) };
let chan = Chan { next: Mut::new(cone) };
let port = Port { next: RefCell::new(Some(pone)) };
let chan = Chan { next: RefCell::new(cone) };
return (port, chan);
}

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@ -9,21 +9,21 @@
// except according to those terms.
use std::rc::Rc;
use std::mutable::Mut;
use std::cell::RefCell;
trait Foo
{
fn set(&mut self, v: Rc<Mut<A>>);
fn set(&mut self, v: Rc<RefCell<A>>);
}
struct B
{
v: Option<Rc<Mut<A>>>
v: Option<Rc<RefCell<A>>>
}
impl Foo for B
{
fn set(&mut self, v: Rc<Mut<A>>)
fn set(&mut self, v: Rc<RefCell<A>>)
{
self.v = Some(v);
}
@ -37,7 +37,7 @@ struct A
fn main()
{
let a = A {v: ~B{v: None} as ~Foo}; //~ ERROR cannot pack type `~B`, which does not fulfill `Send`
let v = Rc::from_send(Mut::new(a));
let v = Rc::from_send(RefCell::new(a));
let w = v.clone();
let b = v.borrow();
let mut b = b.borrow_mut();

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@ -8,10 +8,10 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::mutable::Mut;
use std::cell::RefCell;
fn main() {
let m = Mut::new(0);
let m = RefCell::new(0);
let mut b = m.borrow_mut();
let b1 = b.get();
let b2 = b.get(); //~ ERROR cannot borrow `b` as mutable more than once at a time

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@ -8,11 +8,11 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::mutable::Mut;
use std::cell::RefCell;
fn f<T: Freeze>(_: T) {}
fn main() {
let x = Mut::new(0);
let x = RefCell::new(0);
f(x); //~ ERROR: which does not fulfill `Freeze`
}

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@ -8,10 +8,10 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::mutable::Mut;
use std::cell::RefCell;
fn main() {
let m = Mut::new(0);
let m = RefCell::new(0);
let p;
{
let b = m.borrow();

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@ -8,14 +8,14 @@
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use std::mutable::Mut;
use std::cell::RefCell;
use std::rc::Rc;
fn o<T: Send>(_: &T) {}
fn c<T: Freeze>(_: &T) {}
fn main() {
let x = Rc::from_send(Mut::new(0));
o(&x); //~ ERROR instantiating a type parameter with an incompatible type `std::rc::Rc<std::mutable::Mut<int>>`, which does not fulfill `Send`
c(&x); //~ ERROR instantiating a type parameter with an incompatible type `std::rc::Rc<std::mutable::Mut<int>>`, which does not fulfill `Freeze`
let x = Rc::from_send(RefCell::new(0));
o(&x); //~ ERROR instantiating a type parameter with an incompatible type `std::rc::Rc<std::cell::RefCell<int>>`, which does not fulfill `Send`
c(&x); //~ ERROR instantiating a type parameter with an incompatible type `std::rc::Rc<std::cell::RefCell<int>>`, which does not fulfill `Freeze`
}