Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 726 insertions, 0 deletions

diff --git a/third_party/rust/id-arena/src/lib.rs b/third_party/rust/id-arena/src/lib.rs
new file mode 100644
index 0000000000..0c0edd4e60
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+++ b/third_party/rust/id-arena/src/lib.rs
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+//! [![](https://img.shields.io/crates/v/id-arena.svg)](https://crates.io/crates/id-arena)
+//! [![](https://img.shields.io/crates/d/id-arena.svg)](https://crates.io/crates/id-arena)
+//! [![Travis CI Build Status](https://travis-ci.org/fitzgen/id-arena.svg?branch=master)](https://travis-ci.org/fitzgen/id-arena)
+//!
+//! A simple, id-based arena.
+//!
+//! ## Id-based
+//!
+//! Allocate objects and get an identifier for that object back, *not* a
+//! reference to the allocated object. Given an id, you can get a shared or
+//! exclusive reference to the allocated object from the arena. This id-based
+//! approach is useful for constructing mutable graph data structures.
+//!
+//! If you want allocation to return a reference, consider [the `typed-arena`
+//! crate](https://github.com/SimonSapin/rust-typed-arena/) instead.
+//!
+//! ## No Deletion
+//!
+//! This arena does not support deletion, which makes its implementation simple
+//! and allocation fast. If you want deletion, you need a way to solve the ABA
+//! problem. Consider using [the `generational-arena`
+//! crate](https://github.com/fitzgen/generational-arena) instead.
+//!
+//! ## Homogeneous
+//!
+//! This crate's arenas can only contain objects of a single type `T`. If you
+//! need an arena of objects with heterogeneous types, consider another crate.
+//!
+//! ## `#![no_std]` Support
+//!
+//! Requires the `alloc` nightly feature. Disable the on-by-default `"std"` feature:
+//!
+//! ```toml
+//! [dependencies.id-arena]
+//! version = "2"
+//! default-features = false
+//! ```
+//!
+//! ## `rayon` Support
+//!
+//! If the `rayon` feature of this crate is activated:
+//!
+//! ```toml
+//! [dependencies]
+//! id-arena = { version = "2", features = ["rayon"] }
+//! ```
+//!
+//! then you can use [`rayon`](https://crates.io/crates/rayon)'s support for
+//! parallel iteration. The `Arena` type will have a `par_iter` family of
+//! methods where appropriate.
+//!
+//! ## Example
+//!
+//! ```rust
+//! use id_arena::{Arena, Id};
+//!
+//! type AstNodeId = Id<AstNode>;
+//!
+//! #[derive(Debug, Eq, PartialEq)]
+//! pub enum AstNode {
+//!     Const(i64),
+//!     Var(String),
+//!     Add {
+//!         lhs: AstNodeId,
+//!         rhs: AstNodeId,
+//!     },
+//!     Sub {
+//!         lhs: AstNodeId,
+//!         rhs: AstNodeId,
+//!     },
+//!     Mul {
+//!         lhs: AstNodeId,
+//!         rhs: AstNodeId,
+//!     },
+//!     Div {
+//!         lhs: AstNodeId,
+//!         rhs: AstNodeId,
+//!     },
+//! }
+//!
+//! let mut ast_nodes = Arena::<AstNode>::new();
+//!
+//! // Create the AST for `a * (b + 3)`.
+//! let three = ast_nodes.alloc(AstNode::Const(3));
+//! let b = ast_nodes.alloc(AstNode::Var("b".into()));
+//! let b_plus_three = ast_nodes.alloc(AstNode::Add {
+//!     lhs: b,
+//!     rhs: three,
+//! });
+//! let a = ast_nodes.alloc(AstNode::Var("a".into()));
+//! let a_times_b_plus_three = ast_nodes.alloc(AstNode::Mul {
+//!     lhs: a,
+//!     rhs: b_plus_three,
+//! });
+//!
+//! // Can use indexing to access allocated nodes.
+//! assert_eq!(ast_nodes[three], AstNode::Const(3));
+//! ```
+
+#![forbid(unsafe_code)]
+#![deny(missing_debug_implementations)]
+#![deny(missing_docs)]
+// In no-std mode, use the alloc crate to get `Vec`.
+#![no_std]
+#![cfg_attr(not(feature = "std"), feature(alloc))]
+
+use core::cmp::Ordering;
+use core::fmt;
+use core::hash::{Hash, Hasher};
+use core::iter;
+use core::marker::PhantomData;
+use core::ops;
+use core::slice;
+use core::sync::atomic::{self, AtomicUsize, ATOMIC_USIZE_INIT};
+
+#[cfg(not(feature = "std"))]
+extern crate alloc;
+#[cfg(not(feature = "std"))]
+use alloc::vec::{self, Vec};
+
+#[cfg(feature = "std")]
+extern crate std;
+#[cfg(feature = "std")]
+use std::vec::{self, Vec};
+
+#[cfg(feature = "rayon")]
+mod rayon;
+#[cfg(feature = "rayon")]
+pub use rayon::*;
+
+/// A trait representing the implementation behavior of an arena and how
+/// identifiers are represented.
+///
+/// ## When should I implement `ArenaBehavior` myself?
+///
+/// Usually, you should just use `DefaultArenaBehavior`, which is simple and
+/// correct. However, there are some scenarios where you might want to implement
+/// `ArenaBehavior` yourself:
+///
+/// * **Space optimizations:** The default identifier is two words in size,
+/// which is larger than is usually necessary. For example, if you know that an
+/// arena *cannot* contain more than 256 items, you could make your own
+/// identifier type that stores the index as a `u8` and then you can save some
+/// space.
+///
+/// * **Trait Coherence:** If you need to implement an upstream crate's traits
+/// for identifiers, then defining your own identifier type allows you to work
+/// with trait coherence rules.
+///
+/// * **Share identifiers across arenas:** You can coordinate and share
+/// identifiers across different arenas to enable a "struct of arrays" style
+/// data representation.
+pub trait ArenaBehavior {
+    /// The identifier type.
+    type Id: Copy;
+
+    /// Construct a new object identifier from the given index and arena
+    /// identifier.
+    ///
+    /// ## Panics
+    ///
+    /// Implementations are allowed to panic if the given index is larger than
+    /// the underlying storage (e.g. the implementation uses a `u8` for storing
+    /// indices and the given index value is larger than 255).
+    fn new_id(arena_id: u32, index: usize) -> Self::Id;
+
+    /// Get the given identifier's index.
+    fn index(Self::Id) -> usize;
+
+    /// Get the given identifier's arena id.
+    fn arena_id(Self::Id) -> u32;
+
+    /// Construct a new arena identifier.
+    ///
+    /// This is used to disambiguate `Id`s across different arenas. To make
+    /// identifiers with the same index from different arenas compare false for
+    /// equality, return a unique `u32` on every invocation. This is the
+    /// default, provided implementation's behavior.
+    ///
+    /// To make identifiers with the same index from different arenas compare
+    /// true for equality, return the same `u32` on every invocation.
+    fn new_arena_id() -> u32 {
+        static ARENA_COUNTER: AtomicUsize = ATOMIC_USIZE_INIT;
+        ARENA_COUNTER.fetch_add(1, atomic::Ordering::SeqCst) as u32
+    }
+}
+
+/// An identifier for an object allocated within an arena.
+pub struct Id<T> {
+    idx: usize,
+    arena_id: u32,
+    _ty: PhantomData<fn() -> T>,
+}
+
+impl<T> fmt::Debug for Id<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_struct("Id").field("idx", &self.idx).finish()
+    }
+}
+
+impl<T> Copy for Id<T> {}
+
+impl<T> Clone for Id<T> {
+    #[inline]
+    fn clone(&self) -> Id<T> {
+        *self
+    }
+}
+
+impl<T> PartialEq for Id<T> {
+    #[inline]
+    fn eq(&self, rhs: &Self) -> bool {
+        self.arena_id == rhs.arena_id && self.idx == rhs.idx
+    }
+}
+
+impl<T> Eq for Id<T> {}
+
+impl<T> Hash for Id<T> {
+    #[inline]
+    fn hash<H: Hasher>(&self, h: &mut H) {
+        self.arena_id.hash(h);
+        self.idx.hash(h);
+    }
+}
+
+impl<T> PartialOrd for Id<T> {
+    fn partial_cmp(&self, rhs: &Self) -> Option<Ordering> {
+        Some(self.cmp(rhs))
+    }
+}
+
+impl<T> Ord for Id<T> {
+    fn cmp(&self, rhs: &Self) -> Ordering {
+        self.arena_id
+            .cmp(&rhs.arena_id)
+            .then(self.idx.cmp(&rhs.idx))
+    }
+}
+
+impl<T> Id<T> {
+    /// Get the index within the arena that this id refers to.
+    #[inline]
+    pub fn index(&self) -> usize {
+        self.idx
+    }
+}
+
+/// The default `ArenaBehavior` implementation.
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct DefaultArenaBehavior<T> {
+    _phantom: PhantomData<fn() -> T>,
+}
+
+impl<T> ArenaBehavior for DefaultArenaBehavior<T> {
+    type Id = Id<T>;
+
+    #[inline]
+    fn new_id(arena_id: u32, idx: usize) -> Self::Id {
+        Id {
+            idx,
+            arena_id,
+            _ty: PhantomData,
+        }
+    }
+
+    #[inline]
+    fn index(id: Self::Id) -> usize {
+        id.idx
+    }
+
+    #[inline]
+    fn arena_id(id: Self::Id) -> u32 {
+        id.arena_id
+    }
+}
+
+/// An arena of objects of type `T`.
+///
+/// ```
+/// use id_arena::Arena;
+///
+/// let mut arena = Arena::<&str>::new();
+///
+/// let a = arena.alloc("Albert");
+/// assert_eq!(arena[a], "Albert");
+///
+/// arena[a] = "Alice";
+/// assert_eq!(arena[a], "Alice");
+/// ```
+#[derive(Clone, Debug, PartialEq, Eq)]
+pub struct Arena<T, A = DefaultArenaBehavior<T>> {
+    arena_id: u32,
+    items: Vec<T>,
+    _phantom: PhantomData<fn() -> A>,
+}
+
+impl<T, A> Default for Arena<T, A>
+where
+    A: ArenaBehavior,
+{
+    #[inline]
+    fn default() -> Arena<T, A> {
+        Arena {
+            arena_id: A::new_arena_id(),
+            items: Vec::new(),
+            _phantom: PhantomData,
+        }
+    }
+}
+
+impl<T, A> Arena<T, A>
+where
+    A: ArenaBehavior,
+{
+    /// Construct a new, empty `Arena`.
+    ///
+    /// ```
+    /// use id_arena::Arena;
+    ///
+    /// let mut arena = Arena::<usize>::new();
+    /// arena.alloc(42);
+    /// ```
+    #[inline]
+    pub fn new() -> Arena<T, A> {
+        Default::default()
+    }
+
+    /// Construct a new, empty `Arena` with capacity for the given number of
+    /// elements.
+    ///
+    /// ```
+    /// use id_arena::Arena;
+    ///
+    /// let mut arena = Arena::<usize>::with_capacity(100);
+    /// for x in 0..100 {
+    ///     arena.alloc(x * x);
+    /// }
+    /// ```
+    #[inline]
+    pub fn with_capacity(capacity: usize) -> Arena<T, A> {
+        Arena {
+            arena_id: A::new_arena_id(),
+            items: Vec::with_capacity(capacity),
+            _phantom: PhantomData,
+        }
+    }
+
+    /// Allocate `item` within this arena and return its id.
+    ///
+    /// ```
+    /// use id_arena::Arena;
+    ///
+    /// let mut arena = Arena::<usize>::new();
+    /// let _id = arena.alloc(42);
+    /// ```
+    ///
+    /// ## Panics
+    ///
+    /// Panics if the number of elements in the arena overflows a `usize` or
+    /// `Id`'s index storage representation.
+    #[inline]
+    pub fn alloc(&mut self, item: T) -> A::Id {
+        let id = self.next_id();
+        self.items.push(item);
+        id
+    }
+
+    /// Allocate an item with the id that it will be assigned.
+    ///
+    /// This is useful for structures that want to store their id as their own
+    /// member.
+    ///
+    /// ```
+    /// use id_arena::{Arena, Id};
+    ///
+    /// struct Cat {
+    ///     id: Id<Cat>,
+    /// }
+    ///
+    /// let mut arena = Arena::<Cat>::new();
+    ///
+    /// let kitty = arena.alloc_with_id(|id| Cat { id });
+    /// assert_eq!(arena[kitty].id, kitty);
+    /// ```
+    #[inline]
+    pub fn alloc_with_id(&mut self, f: impl FnOnce(A::Id) -> T) -> A::Id {
+        let id = self.next_id();
+        let val = f(id);
+        self.alloc(val)
+    }
+
+    /// Get the id that will be used for the next item allocated into this
+    /// arena.
+    ///
+    /// If you are allocating a `struct` that wants to have its id as a member
+    /// of itself, prefer the less error-prone `Arena::alloc_with_id` method.
+    #[inline]
+    pub fn next_id(&self) -> A::Id {
+        let arena_id = self.arena_id;
+        let idx = self.items.len();
+        A::new_id(arena_id, idx)
+    }
+
+    /// Get a shared reference to the object associated with the given `id` if
+    /// it exists.
+    ///
+    /// If there is no object associated with `id` (for example, it might
+    /// reference an object allocated within a different arena) then return
+    /// `None`.
+    ///
+    /// ```
+    /// use id_arena::Arena;
+    ///
+    /// let mut arena = Arena::<usize>::new();
+    /// let id = arena.alloc(42);
+    /// assert!(arena.get(id).is_some());
+    ///
+    /// let other_arena = Arena::<usize>::new();
+    /// assert!(other_arena.get(id).is_none());
+    /// ```
+    #[inline]
+    pub fn get(&self, id: A::Id) -> Option<&T> {
+        if A::arena_id(id) != self.arena_id {
+            None
+        } else {
+            self.items.get(A::index(id))
+        }
+    }
+
+    /// Get an exclusive reference to the object associated with the given `id`
+    /// if it exists.
+    ///
+    /// If there is no object associated with `id` (for example, it might
+    /// reference an object allocated within a different arena) then return
+    /// `None`.
+    ///
+    /// ```
+    /// use id_arena::Arena;
+    ///
+    /// let mut arena = Arena::<usize>::new();
+    /// let id = arena.alloc(42);
+    /// assert!(arena.get_mut(id).is_some());
+    ///
+    /// let mut other_arena = Arena::<usize>::new();
+    /// assert!(other_arena.get_mut(id).is_none());
+    /// ```
+    #[inline]
+    pub fn get_mut(&mut self, id: A::Id) -> Option<&mut T> {
+        if A::arena_id(id) != self.arena_id {
+            None
+        } else {
+            self.items.get_mut(A::index(id))
+        }
+    }
+
+    /// Iterate over this arena's items and their ids.
+    ///
+    /// ```
+    /// use id_arena::Arena;
+    ///
+    /// let mut arena = Arena::<&str>::new();
+    ///
+    /// arena.alloc("hello");
+    /// arena.alloc("hi");
+    /// arena.alloc("yo");
+    ///
+    /// for (id, s) in arena.iter() {
+    ///     assert_eq!(arena.get(id).unwrap(), s);
+    ///     println!("{:?} -> {}", id, s);
+    /// }
+    /// ```
+    #[inline]
+    pub fn iter(&self) -> Iter<T, A> {
+        IntoIterator::into_iter(self)
+    }
+
+    /// Iterate over this arena's items and their ids, allowing mutation of each
+    /// item.
+    #[inline]
+    pub fn iter_mut(&mut self) -> IterMut<T, A> {
+        IntoIterator::into_iter(self)
+    }
+
+    /// Get the number of objects allocated in this arena.
+    ///
+    /// ```
+    /// use id_arena::Arena;
+    ///
+    /// let mut arena = Arena::<&str>::new();
+    ///
+    /// arena.alloc("hello");
+    /// arena.alloc("hi");
+    ///
+    /// assert_eq!(arena.len(), 2);
+    /// ```
+    #[inline]
+    pub fn len(&self) -> usize {
+        self.items.len()
+    }
+}
+
+impl<T, A> ops::Index<A::Id> for Arena<T, A>
+where
+    A: ArenaBehavior,
+{
+    type Output = T;
+
+    #[inline]
+    fn index(&self, id: A::Id) -> &T {
+        assert_eq!(self.arena_id, A::arena_id(id));
+        &self.items[A::index(id)]
+    }
+}
+
+impl<T, A> ops::IndexMut<A::Id> for Arena<T, A>
+where
+    A: ArenaBehavior,
+{
+    #[inline]
+    fn index_mut(&mut self, id: A::Id) -> &mut T {
+        assert_eq!(self.arena_id, A::arena_id(id));
+        &mut self.items[A::index(id)]
+    }
+}
+
+fn add_id<A, T>(item: Option<(usize, T)>, arena_id: u32) -> Option<(A::Id, T)>
+where
+    A: ArenaBehavior,
+{
+    item.map(|(idx, item)| (A::new_id(arena_id, idx), item))
+}
+
+/// An iterator over `(Id, &T)` pairs in an arena.
+///
+/// See [the `Arena::iter()` method](./struct.Arena.html#method.iter) for details.
+#[derive(Debug)]
+pub struct Iter<'a, T: 'a, A: 'a> {
+    arena_id: u32,
+    iter: iter::Enumerate<slice::Iter<'a, T>>,
+    _phantom: PhantomData<fn() -> A>,
+}
+
+impl<'a, T: 'a, A: 'a> Iterator for Iter<'a, T, A>
+where
+    A: ArenaBehavior,
+{
+    type Item = (A::Id, &'a T);
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        add_id::<A, _>(self.iter.next(), self.arena_id)
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+}
+
+impl<'a, T: 'a, A: 'a> DoubleEndedIterator for Iter<'a, T, A>
+where
+    A: ArenaBehavior,
+{
+    fn next_back(&mut self) -> Option<Self::Item> {
+        add_id::<A, _>(self.iter.next_back(), self.arena_id)
+    }
+}
+
+impl<'a, T: 'a, A: 'a> ExactSizeIterator for Iter<'a, T, A>
+where
+    A: ArenaBehavior,
+{
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+}
+
+impl<'a, T, A> IntoIterator for &'a Arena<T, A>
+where
+    A: ArenaBehavior,
+{
+    type Item = (A::Id, &'a T);
+    type IntoIter = Iter<'a, T, A>;
+
+    #[inline]
+    fn into_iter(self) -> Iter<'a, T, A> {
+        Iter {
+            arena_id: self.arena_id,
+            iter: self.items.iter().enumerate(),
+            _phantom: PhantomData,
+        }
+    }
+}
+
+/// An iterator over `(Id, &mut T)` pairs in an arena.
+///
+/// See [the `Arena::iter_mut()` method](./struct.Arena.html#method.iter_mut)
+/// for details.
+#[derive(Debug)]
+pub struct IterMut<'a, T: 'a, A: 'a> {
+    arena_id: u32,
+    iter: iter::Enumerate<slice::IterMut<'a, T>>,
+    _phantom: PhantomData<fn() -> A>,
+}
+
+impl<'a, T: 'a, A: 'a> Iterator for IterMut<'a, T, A>
+where
+    A: ArenaBehavior,
+{
+    type Item = (A::Id, &'a mut T);
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        add_id::<A, _>(self.iter.next(), self.arena_id)
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+}
+
+impl<'a, T: 'a, A: 'a> DoubleEndedIterator for IterMut<'a, T, A>
+where
+    A: ArenaBehavior,
+{
+    fn next_back(&mut self) -> Option<Self::Item> {
+        add_id::<A, _>(self.iter.next_back(), self.arena_id)
+    }
+}
+
+impl<'a, T: 'a, A: 'a> ExactSizeIterator for IterMut<'a, T, A>
+where
+    A: ArenaBehavior,
+{
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+}
+
+impl<'a, T, A> IntoIterator for &'a mut Arena<T, A>
+where
+    A: ArenaBehavior,
+{
+    type Item = (A::Id, &'a mut T);
+    type IntoIter = IterMut<'a, T, A>;
+
+    #[inline]
+    fn into_iter(self) -> IterMut<'a, T, A> {
+        IterMut {
+            arena_id: self.arena_id,
+            iter: self.items.iter_mut().enumerate(),
+            _phantom: PhantomData,
+        }
+    }
+}
+
+/// An iterator over `(Id, T)` pairs in an arena.
+#[derive(Debug)]
+pub struct IntoIter<T, A> {
+    arena_id: u32,
+    iter: iter::Enumerate<vec::IntoIter<T>>,
+    _phantom: PhantomData<fn() -> A>,
+}
+
+impl<T, A> Iterator for IntoIter<T, A>
+where
+    A: ArenaBehavior,
+{
+    type Item = (A::Id, T);
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        add_id::<A, _>(self.iter.next(), self.arena_id)
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+}
+
+impl<T, A> DoubleEndedIterator for IntoIter<T, A>
+where
+    A: ArenaBehavior,
+{
+    fn next_back(&mut self) -> Option<Self::Item> {
+        add_id::<A, _>(self.iter.next_back(), self.arena_id)
+    }
+}
+
+impl<T, A> ExactSizeIterator for IntoIter<T, A>
+where
+    A: ArenaBehavior,
+{
+    fn len(&self) -> usize {
+        self.iter.len()
+    }
+}
+
+impl<T, A> IntoIterator for Arena<T, A>
+where
+    A: ArenaBehavior,
+{
+    type Item = (A::Id, T);
+    type IntoIter = IntoIter<T, A>;
+
+    #[inline]
+    fn into_iter(self) -> IntoIter<T, A> {
+        IntoIter {
+            arena_id: self.arena_id,
+            iter: self.items.into_iter().enumerate(),
+            _phantom: PhantomData,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn ids_are_send_sync() {
+        fn assert_send_sync<T: Send + Sync>() {}
+        struct Foo;
+        assert_send_sync::<Id<Foo>>();
+    }
+}