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Remove unused style::refcell module.

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Ms2ger 2016-12-16 14:30:01 +01:00
parent 0bc8415485
commit ce0a402bc8
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1
components/style/lib.rs
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@ -113,7 +113,6 @@ pub mod media_queries;
pub mod owning_handle;
pub mod parallel;
pub mod parser;
pub mod refcell;
pub mod restyle_hints;
pub mod rule_tree;
pub mod selector_parser;

647
components/style/refcell.rs
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@ -1,647 +0,0 @@
// Copyright 2012-2014 The Rust Project Developers.
// See 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 fork of std::cell::RefCell that makes `as_unsafe_cell` usable on stable Rust.
//!
//! FIXME(https://github.com/rust-lang/rust/issues/27708): Remove this
//! (revert commit f7f81e0ed0b62402db291e28a9bb16f7194ebf78 / PR #11835)
//! when `std::cell::RefCell::as_unsafe_cell` is in Rust’s stable channel.
#![allow(unsafe_code)]
use std::cell::{UnsafeCell, Cell};
use std::cmp::Ordering;
use std::fmt::{self, Debug, Display};
use std::marker::PhantomData;
use std::ops::{Deref, DerefMut};
/// A fork of std::cell::RefCell that makes `as_unsafe_cell` usable on stable Rust.
///
/// FIXME(https://github.com/rust-lang/rust/issues/27708): Remove this
/// (revert commit f7f81e0ed0b62402db291e28a9bb16f7194ebf78 / PR #11835)
/// when `std::cell::RefCell::as_unsafe_cell` is in Rust’s stable channel.
pub struct RefCell<T: ?Sized> {
borrow: Cell<BorrowFlag>,
value: UnsafeCell<T>,
}
/// An enumeration of values returned from the `state` method on a `RefCell<T>`.
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub enum BorrowState {
/// The cell is currently being read, there is at least one active `borrow`.
Reading,
/// The cell is currently being written to, there is an active `borrow_mut`.
Writing,
/// There are no outstanding borrows on this cell.
Unused,
}
/// An error returned by [`RefCell::try_borrow`](struct.RefCell.html#method.try_borrow).
pub struct BorrowError<'a, T: 'a + ?Sized> {
marker: PhantomData<&'a RefCell<T>>,
}
impl<'a, T: ?Sized> Debug for BorrowError<'a, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_struct("BorrowError").finish()
}
}
impl<'a, T: ?Sized> Display for BorrowError<'a, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
Display::fmt("already mutably borrowed", f)
}
}
/// An error returned by [`RefCell::try_borrow_mut`](struct.RefCell.html#method.try_borrow_mut).
pub struct BorrowMutError<'a, T: 'a + ?Sized> {
marker: PhantomData<&'a RefCell<T>>,
}
impl<'a, T: ?Sized> Debug for BorrowMutError<'a, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.debug_struct("BorrowMutError").finish()
}
}
impl<'a, T: ?Sized> Display for BorrowMutError<'a, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
Display::fmt("already borrowed", f)
}
}
// Values [1, MAX-1] represent the number of `Ref` active
// (will not outgrow its range since `usize` is the size of the address space)
type BorrowFlag = usize;
const UNUSED: BorrowFlag = 0;
const WRITING: BorrowFlag = !0;
impl<T> RefCell<T> {
/// Creates a new `RefCell` containing `value`.
///
/// # Examples
///
/// ```
/// use std::cell::RefCell;
///
/// let c = RefCell::new(5);
/// ```
#[inline]
pub fn new(value: T) -> RefCell<T> {
RefCell {
value: UnsafeCell::new(value),
borrow: Cell::new(UNUSED),
}
}
/// Consumes the `RefCell`, returning the wrapped value.
///
/// # Examples
///
/// ```
/// use std::cell::RefCell;
///
/// let c = RefCell::new(5);
///
/// let five = c.into_inner();
/// ```
#[inline]
pub fn into_inner(self) -> T {
// Since this function takes `self` (the `RefCell`) by value, the
// compiler statically verifies that it is not currently borrowed.
// Therefore the following assertion is just a `debug_assert!`.
debug_assert!(self.borrow.get() == UNUSED);
unsafe { self.value.into_inner() }
}
}
impl<T: ?Sized> RefCell<T> {
/// Query the current state of this `RefCell`
///
/// The returned value can be dispatched on to determine if a call to
/// `borrow` or `borrow_mut` would succeed.
///
/// # Examples
///
/// ```
/// #![feature(borrow_state)]
///
/// use std::cell::{BorrowState, RefCell};
///
/// let c = RefCell::new(5);
///
/// match c.borrow_state() {
/// BorrowState::Writing => println!("Cannot be borrowed"),
/// BorrowState::Reading => println!("Cannot be borrowed mutably"),
/// BorrowState::Unused => println!("Can be borrowed (mutably as well)"),
/// }
/// ```
#[inline]
pub fn borrow_state(&self) -> BorrowState {
match self.borrow.get() {
WRITING => BorrowState::Writing,
UNUSED => BorrowState::Unused,
_ => BorrowState::Reading,
}
}
/// 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`](#method.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;
/// use std::thread;
///
/// let result = thread::spawn(move || {
/// let c = RefCell::new(5);
/// let m = c.borrow_mut();
///
/// let b = c.borrow(); // this causes a panic
/// }).join();
///
/// assert!(result.is_err());
/// ```
#[inline]
pub fn borrow(&self) -> Ref<T> {
self.try_borrow().expect("already mutably borrowed")
}
/// 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`](#method.borrow).
///
/// # Examples
///
/// ```
/// #![feature(try_borrow)]
///
/// 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());
/// }
/// ```
#[inline]
pub fn try_borrow(&self) -> Result<Ref<T>, BorrowError<T>> {
match BorrowRef::new(&self.borrow) {
Some(b) => Ok(Ref {
value: unsafe { &*self.value.get() },
borrow: b,
}),
None => Err(BorrowError { marker: PhantomData }),
}
}
/// Mutably borrows the wrapped value.
///
/// The borrow lasts until the returned `RefMut` exits 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`](#method.try_borrow_mut).
///
/// # Examples
///
/// ```
/// use std::cell::RefCell;
///
/// let c = RefCell::new(5);
///
/// *c.borrow_mut() = 7;
///
/// assert_eq!(*c.borrow(), 7);
/// ```
///
/// An example of panic:
///
/// ```
/// use std::cell::RefCell;
/// use std::thread;
///
/// let result = thread::spawn(move || {
/// let c = RefCell::new(5);
/// let m = c.borrow();
///
/// let b = c.borrow_mut(); // this causes a panic
/// }).join();
///
/// assert!(result.is_err());
/// ```
#[inline]
pub fn borrow_mut(&self) -> RefMut<T> {
self.try_borrow_mut().expect("already borrowed")
}
/// Mutably borrows the wrapped value, returning an error if the value is currently borrowed.
///
/// The borrow lasts until the returned `RefMut` exits scope. The value cannot be borrowed
/// while this borrow is active.
///
/// This is the non-panicking variant of [`borrow_mut`](#method.borrow_mut).
///
/// # Examples
///
/// ```
/// #![feature(try_borrow)]
///
/// 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());
/// ```
#[inline]
pub fn try_borrow_mut(&self) -> Result<RefMut<T>, BorrowMutError<T>> {
match BorrowRefMut::new(&self.borrow) {
Some(b) => Ok(RefMut {
value: unsafe { &mut *self.value.get() },
borrow: b,
}),
None => Err(BorrowMutError { marker: PhantomData }),
}
}
/// Returns a reference to the underlying `UnsafeCell`.
///
/// This can be used to circumvent `RefCell`'s safety checks.
///
/// This function is `unsafe` because `UnsafeCell`'s field is public.
///
/// # Examples
///
/// ```
/// #![feature(as_unsafe_cell)]
///
/// use std::cell::RefCell;
///
/// let c = RefCell::new(5);
/// let c = unsafe { c.as_unsafe_cell() };
/// ```
#[inline]
pub unsafe fn as_unsafe_cell(&self) -> &UnsafeCell<T> {
&self.value
}
/// 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();
/// ```
#[inline]
pub fn as_ptr(&self) -> *mut T {
self.value.get()
}
/// Returns a mutable reference to the underlying data.
///
/// This call borrows `RefCell` mutably (at compile-time) so there is no
/// need for dynamic checks.
///
/// # Examples
///
/// ```
/// use std::cell::RefCell;
///
/// let mut c = RefCell::new(5);
/// *c.get_mut() += 1;
///
/// assert_eq!(c, RefCell::new(6));
/// ```
#[inline]
pub fn get_mut(&mut self) -> &mut T {
unsafe {
&mut *self.value.get()
}
}
}
unsafe impl<T: ?Sized> Send for RefCell<T> where T: Send {}
impl<T: Clone> Clone for RefCell<T> {
#[inline]
fn clone(&self) -> RefCell<T> {
RefCell::new(self.borrow().clone())
}
}
impl<T: Default> Default for RefCell<T> {
#[inline]
fn default() -> RefCell<T> {
RefCell::new(Default::default())
}
}
impl<T: ?Sized + PartialEq> PartialEq for RefCell<T> {
#[inline]
fn eq(&self, other: &RefCell<T>) -> bool {
*self.borrow() == *other.borrow()
}
}
impl<T: ?Sized + Eq> Eq for RefCell<T> {}
impl<T: ?Sized + PartialOrd> PartialOrd for RefCell<T> {
#[inline]
fn partial_cmp(&self, other: &RefCell<T>) -> Option<Ordering> {
self.borrow().partial_cmp(&*other.borrow())
}
#[inline]
fn lt(&self, other: &RefCell<T>) -> bool {
*self.borrow() < *other.borrow()
}
#[inline]
fn le(&self, other: &RefCell<T>) -> bool {
*self.borrow() <= *other.borrow()
}
#[inline]
fn gt(&self, other: &RefCell<T>) -> bool {
*self.borrow() > *other.borrow()
}
#[inline]
fn ge(&self, other: &RefCell<T>) -> bool {
*self.borrow() >= *other.borrow()
}
}
impl<T: ?Sized + Ord> Ord for RefCell<T> {
#[inline]
fn cmp(&self, other: &RefCell<T>) -> Ordering {
self.borrow().cmp(&*other.borrow())
}
}
struct BorrowRef<'b> {
borrow: &'b Cell<BorrowFlag>,
}
impl<'b> BorrowRef<'b> {
#[inline]
fn new(borrow: &'b Cell<BorrowFlag>) -> Option<BorrowRef<'b>> {
match borrow.get() {
WRITING => None,
b => {
borrow.set(b + 1);
Some(BorrowRef { borrow: borrow })
},
}
}
}
impl<'b> Drop for BorrowRef<'b> {
#[inline]
fn drop(&mut self) {
let borrow = self.borrow.get();
debug_assert!(borrow != WRITING && borrow != UNUSED);
self.borrow.set(borrow - 1);
}
}
impl<'b> Clone for BorrowRef<'b> {
#[inline]
fn clone(&self) -> BorrowRef<'b> {
// Since this Ref exists, we know the borrow flag
// is not set to WRITING.
let borrow = self.borrow.get();
debug_assert!(borrow != UNUSED);
// Prevent the borrow counter from overflowing.
assert!(borrow != WRITING);
self.borrow.set(borrow + 1);
BorrowRef { borrow: self.borrow }
}
}
/// Wraps a borrowed reference to a value in a `RefCell` box.
/// A wrapper type for an immutably borrowed value from a `RefCell<T>`.
///
/// See the [module-level documentation](index.html) for more.
pub struct Ref<'b, T: ?Sized + 'b> {
value: &'b T,
borrow: BorrowRef<'b>,
}
impl<'b, T: ?Sized> Deref for Ref<'b, T> {
type Target = T;
#[inline]
fn deref(&self) -> &T {
self.value
}
}
impl<'b, T: ?Sized> Ref<'b, T> {
/// Copies a `Ref`.
///
/// The `RefCell` is already immutably borrowed, so this cannot fail.
///
/// This is an associated function that needs to be used as
/// `Ref::clone(...)`. A `Clone` implementation or a method would interfere
/// with the widespread use of `r.borrow().clone()` to clone the contents of
/// a `RefCell`.
#[inline]
pub fn clone(orig: &Ref<'b, T>) -> Ref<'b, T> {
Ref {
value: orig.value,
borrow: orig.borrow.clone(),
}
}
/// Make a new `Ref` for a component of the borrowed data.
///
/// The `RefCell` is already immutably borrowed, so this cannot fail.
///
/// This is an associated function that needs to be used as `Ref::map(...)`.
/// A method would interfere with methods of the same name on the contents
/// of a `RefCell` used through `Deref`.
///
/// # Example
///
/// ```
/// use std::cell::{RefCell, Ref};
///
/// let c = RefCell::new((5, 'b'));
/// let b1: Ref<(u32, char)> = c.borrow();
/// let b2: Ref<u32> = Ref::map(b1, |t| &t.0);
/// assert_eq!(*b2, 5)
/// ```
#[inline]
pub fn map<U: ?Sized, F>(orig: Ref<'b, T>, f: F) -> Ref<'b, U>
where F: FnOnce(&T) -> &U
{
Ref {
value: f(orig.value),
borrow: orig.borrow,
}
}
}
impl<'b, T: ?Sized> RefMut<'b, T> {
/// Make a new `RefMut` for a component of the borrowed data, e.g. an enum
/// variant.
///
/// The `RefCell` is already mutably borrowed, so this cannot fail.
///
/// This is an associated function that needs to be used as
/// `RefMut::map(...)`. A method would interfere with methods of the same
/// name on the contents of a `RefCell` used through `Deref`.
///
/// # Example
///
/// ```
/// use std::cell::{RefCell, RefMut};
///
/// let c = RefCell::new((5, 'b'));
/// {
/// let b1: RefMut<(u32, char)> = c.borrow_mut();
/// let mut b2: RefMut<u32> = RefMut::map(b1, |t| &mut t.0);
/// assert_eq!(*b2, 5);
/// *b2 = 42;
/// }
/// assert_eq!(*c.borrow(), (42, 'b'));
/// ```
#[inline]
pub fn map<U: ?Sized, F>(orig: RefMut<'b, T>, f: F) -> RefMut<'b, U>
where F: FnOnce(&mut T) -> &mut U
{
RefMut {
value: f(orig.value),
borrow: orig.borrow,
}
}
}
struct BorrowRefMut<'b> {
borrow: &'b Cell<BorrowFlag>,
}
impl<'b> Drop for BorrowRefMut<'b> {
#[inline]
fn drop(&mut self) {
let borrow = self.borrow.get();
debug_assert!(borrow == WRITING);
self.borrow.set(UNUSED);
}
}
impl<'b> BorrowRefMut<'b> {
#[inline]
fn new(borrow: &'b Cell<BorrowFlag>) -> Option<BorrowRefMut<'b>> {
match borrow.get() {
UNUSED => {
borrow.set(WRITING);
Some(BorrowRefMut { borrow: borrow })
},
_ => None,
}
}
}
/// A wrapper type for a mutably borrowed value from a `RefCell<T>`.
///
/// See the [module-level documentation](index.html) for more.
pub struct RefMut<'b, T: ?Sized + 'b> {
value: &'b mut T,
borrow: BorrowRefMut<'b>,
}
impl<'b, T: ?Sized> Deref for RefMut<'b, T> {
type Target = T;
#[inline]
fn deref(&self) -> &T {
self.value
}
}
impl<'b, T: ?Sized> DerefMut for RefMut<'b, T> {
#[inline]
fn deref_mut(&mut self) -> &mut T {
self.value
}
}
// Imported from src/libcore/fmt/mod.rs
impl<T: ?Sized + Debug> Debug for RefCell<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self.borrow_state() {
BorrowState::Unused | BorrowState::Reading => {
f.debug_struct("RefCell")
.field("value", &self.borrow())
.finish()
}
BorrowState::Writing => {
f.debug_struct("RefCell")
.field("value", &"<borrowed>")
.finish()
}
}
}
}
impl<'b, T: ?Sized + Debug> Debug for Ref<'b, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
Debug::fmt(&**self, f)
}
}
impl<'b, T: ?Sized + Debug> Debug for RefMut<'b, T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
Debug::fmt(&*(self.deref()), f)
}
}