Remove unused style::refcell module.

1 files changed, 0 insertions, 647 deletions

diff --git a/components/style/refcell.rs b/components/style/refcell.rs
deleted file mode 100644
index a41fa2b63b1..00000000000
--- a/components/style/refcell.rs
+++ /dev/null
@@ -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)
-    }
-}