Adding upstream version 115.7.0esr.upstream/115.7.0esr

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

1 files changed, 596 insertions, 0 deletions

diff --git a/third_party/rust/replace_with/src/lib.rs b/third_party/rust/replace_with/src/lib.rs
new file mode 100755
index 0000000000..05ab0fbf04
--- /dev/null
+++ b/third_party/rust/replace_with/src/lib.rs
@@ -0,0 +1,596 @@
+//! Temporarily take ownership of a value at a mutable location, and replace it with a new value
+//! based on the old one.
+//!
+//! <p style="font-family: 'Fira Sans',sans-serif;padding:0.3em 0"><strong>
+//! <a href="https://crates.io/crates/replace_with">📦&nbsp;&nbsp;Crates.io</a>&nbsp;&nbsp;│&nbsp;&nbsp;<a href="https://github.com/alecmocatta/replace_with">📑&nbsp;&nbsp;GitHub</a>&nbsp;&nbsp;│&nbsp;&nbsp;<a href="https://constellation.zulipchat.com/#narrow/stream/213236-subprojects">💬&nbsp;&nbsp;Chat</a>
+//! </strong></p>
+//!
+//! This crate provides the function [`replace_with()`], which is like [`std::mem::replace()`]
+//! except it allows the replacement value to be mapped from the original value.
+//!
+//! See [RFC 1736](https://github.com/rust-lang/rfcs/pull/1736) for a lot of discussion as to its
+//! merits. It was never merged, and the desired ability to temporarily move out of `&mut T` doesn't
+//! exist yet, so this crate is my interim solution.
+//!
+//! It's very akin to [`take_mut`](https://github.com/Sgeo/take_mut), though uses `Drop` instead of
+//! [`std::panic::catch_unwind()`] to react to unwinding, which avoids the optimisation barrier of
+//! calling the `extern "C" __rust_maybe_catch_panic()`. As such it's up to ∞x faster. The API also
+//! attempts to make slightly more explicit the behavior on panic – [`replace_with()`] accepts two
+//! closures such that aborting in the "standard case" where the mapping closure (`FnOnce(T) -> T`)
+//! panics (as [`take_mut::take()`](https://docs.rs/take_mut/0.2.2/take_mut/fn.take.html) does) is
+//! avoided. If the second closure (`FnOnce() -> T`) panics, however, then it does indeed abort.
+//! The "abort on first panic" behaviour is available with [`replace_with_or_abort()`].
+//!
+//! # Example
+//!
+//! Consider this motivating example:
+//!
+//! ```compile_fail
+//! # use replace_with::*;
+//! enum States {
+//!     A(String),
+//!     B(String),
+//! }
+//!
+//! impl States {
+//!     fn poll(&mut self) {
+//!         // error[E0507]: cannot move out of borrowed content
+//!         *self = match *self {
+//!         //            ^^^^^ cannot move out of borrowed content
+//!             States::A(a) => States::B(a),
+//!             States::B(a) => States::A(a),
+//!         };
+//!     }
+//! }
+//! ```
+//!
+//! Depending on context this can be quite tricky to work around. With this crate, however:
+//!
+//! ```
+//! # use replace_with::*;
+//! enum States {
+//!     A(String),
+//!     B(String),
+//! }
+//!
+//! # #[cfg(any(feature = "std", feature = "nightly"))]
+//! impl States {
+//!     fn poll(&mut self) {
+//!         replace_with_or_abort(self, |self_| match self_ {
+//!             States::A(a) => States::B(a),
+//!             States::B(a) => States::A(a),
+//!         });
+//!     }
+//! }
+//! ```
+//!
+//! Huzzah!
+
+#![cfg_attr(not(feature = "std"), no_std)]
+#![cfg_attr(
+	all(not(feature = "std"), feature = "nightly"),
+	feature(core_intrinsics)
+)]
+#![doc(html_root_url = "https://docs.rs/replace_with/0.1.7")]
+#![warn(
+	missing_copy_implementations,
+	missing_debug_implementations,
+	missing_docs,
+	trivial_casts,
+	trivial_numeric_casts,
+	unused_import_braces,
+	unused_qualifications,
+	unused_results,
+	// clippy::pedantic
+)]
+// #![allow(clippy::inline_always)]
+
+#[cfg(not(feature = "std"))]
+use core as std;
+
+use std::{mem, ptr};
+
+struct OnDrop<F: FnOnce()>(mem::ManuallyDrop<F>);
+impl<F: FnOnce()> Drop for OnDrop<F> {
+	#[inline(always)]
+	fn drop(&mut self) {
+		(unsafe { ptr::read(&*self.0) })();
+	}
+}
+
+#[doc(hidden)]
+#[inline(always)]
+pub fn on_unwind<F: FnOnce() -> T, T, P: FnOnce()>(f: F, p: P) -> T {
+	let x = OnDrop(mem::ManuallyDrop::new(p));
+	let t = f();
+	let mut x = mem::ManuallyDrop::new(x);
+	unsafe { mem::ManuallyDrop::drop(&mut x.0) };
+	t
+}
+
+#[doc(hidden)]
+#[inline(always)]
+pub fn on_return_or_unwind<F: FnOnce() -> T, T, P: FnOnce()>(f: F, p: P) -> T {
+	let _x = OnDrop(mem::ManuallyDrop::new(p));
+	f()
+}
+
+/// Temporarily takes ownership of a value at a mutable location, and replace it with a new value
+/// based on the old one.
+///
+/// We move out of the reference temporarily, to apply a closure `f`, returning a new value, which
+/// is then placed at the original value's location.
+///
+/// # An important note
+///
+/// On panic (or to be more precise, unwinding) of the closure `f`, `default` will be called to
+/// provide a replacement value. `default` should not panic – doing so will constitute a double
+/// panic and will most likely abort the process.
+///
+/// # Example
+///
+/// ```
+/// # use replace_with::*;
+/// enum States {
+///     A(String),
+///     B(String),
+/// }
+///
+/// impl States {
+///     fn poll(&mut self) {
+///         replace_with(
+///             self,
+///             || States::A(String::new()),
+///             |self_| match self_ {
+///                 States::A(a) => States::B(a),
+///                 States::B(a) => States::A(a),
+///             },
+///         );
+///     }
+/// }
+/// ```
+#[inline]
+pub fn replace_with<T, D: FnOnce() -> T, F: FnOnce(T) -> T>(dest: &mut T, default: D, f: F) {
+	unsafe {
+		let old = ptr::read(dest);
+		let new = on_unwind(move || f(old), || ptr::write(dest, default()));
+		ptr::write(dest, new);
+	}
+}
+
+/// Temporarily takes ownership of a value at a mutable location, and replace it with a new value
+/// based on the old one. Replaces with [`Default::default()`] on panic.
+///
+/// We move out of the reference temporarily, to apply a closure `f`, returning a new value, which
+/// is then placed at the original value's location.
+///
+/// # An important note
+///
+/// On panic (or to be more precise, unwinding) of the closure `f`, `T::default()` will be called to
+/// provide a replacement value. `T::default()` should not panic – doing so will constitute a double
+/// panic and will most likely abort the process.
+///
+/// Equivalent to `replace_with(dest, T::default, f)`.
+///
+/// Differs from `*dest = mem::replace(dest, Default::default())` in that `Default::default()` will
+/// only be called on panic.
+///
+/// # Example
+///
+/// ```
+/// # use replace_with::*;
+/// enum States {
+///     A(String),
+///     B(String),
+/// }
+///
+/// impl Default for States {
+///     fn default() -> Self {
+///         States::A(String::new())
+///     }
+/// }
+///
+/// impl States {
+///     fn poll(&mut self) {
+///         replace_with_or_default(self, |self_| match self_ {
+///             States::A(a) => States::B(a),
+///             States::B(a) => States::A(a),
+///         });
+///     }
+/// }
+/// ```
+#[inline]
+pub fn replace_with_or_default<T: Default, F: FnOnce(T) -> T>(dest: &mut T, f: F) {
+	replace_with(dest, T::default, f);
+}
+
+/// Temporarily takes ownership of a value at a mutable location, and replace it with a new value
+/// based on the old one. Aborts on panic.
+///
+/// We move out of the reference temporarily, to apply a closure `f`, returning a new value, which
+/// is then placed at the original value's location.
+///
+/// # An important note
+///
+/// On panic (or to be more precise, unwinding) of the closure `f`, the process will **abort** to
+/// avoid returning control while `dest` is in a potentially invalid state.
+///
+/// If this behaviour is undesirable, use [`replace_with`] or [`replace_with_or_default`].
+///
+/// Equivalent to `replace_with(dest, || process::abort(), f)`.
+///
+/// # Example
+///
+/// ```
+/// # use replace_with::*;
+/// enum States {
+///     A(String),
+///     B(String),
+/// }
+///
+/// # #[cfg(any(feature = "std", feature = "nightly"))]
+/// impl States {
+///     fn poll(&mut self) {
+///         replace_with_or_abort(self, |self_| match self_ {
+///             States::A(a) => States::B(a),
+///             States::B(a) => States::A(a),
+///         });
+///     }
+/// }
+/// ```
+#[inline]
+#[cfg(feature = "std")]
+pub fn replace_with_or_abort<T, F: FnOnce(T) -> T>(dest: &mut T, f: F) {
+	replace_with(dest, || std::process::abort(), f);
+}
+
+#[inline]
+#[cfg(all(not(feature = "std"), feature = "nightly"))]
+pub fn replace_with_or_abort<T, F: FnOnce(T) -> T>(dest: &mut T, f: F) {
+	replace_with(dest, || unsafe { std::intrinsics::abort() }, f);
+}
+
+/// Temporarily takes ownership of a value at a mutable location, and replace it with a new value
+/// based on the old one. Aborts on panic.
+///
+/// We move out of the reference temporarily, to apply a closure `f`, returning a new value, which
+/// is then placed at the original value's location.
+///
+/// # An important note
+///
+/// On panic (or to be more precise, unwinding) of the closure `f`, the process will **abort** to
+/// avoid returning control while `dest` is in a potentially invalid state.
+///
+/// Unlike for `replace_with_or_abort()` users of `replace_with_or_abort_unchecked()` are expected
+/// to have `features = ["panic_abort", …]` defined in `Cargo.toml`
+/// and `panic = "abort"` defined in their profile for it to behave semantically correct:
+///
+/// ```toml
+/// # Cargo.toml
+///
+/// [profile.debug]
+/// panic = "abort"
+///
+/// [profile.release]
+/// panic = "abort"
+/// ```
+///
+/// # Safety
+///
+/// It is crucial to only ever use this function having defined `panic = "abort"`, or else bad
+/// things may happen. It's *up to you* to uphold this invariant!
+///
+/// If this behaviour is undesirable, use [`replace_with`] or [`replace_with_or_default`].
+///
+/// Equivalent to `replace_with(dest, || process::abort(), f)`.
+///
+/// # Example
+///
+/// ```
+/// # use replace_with::*;
+/// enum States {
+///     A(String),
+///     B(String),
+/// }
+///
+/// impl States {
+///     fn poll(&mut self) {
+///         unsafe {
+///             replace_with_or_abort_unchecked(self, |self_| match self_ {
+///                 States::A(a) => States::B(a),
+///                 States::B(a) => States::A(a),
+///             });
+///         }
+///     }
+/// }
+/// ```
+///
+#[inline]
+#[cfg(feature = "panic_abort")]
+pub unsafe fn replace_with_or_abort_unchecked<T, F: FnOnce(T) -> T>(dest: &mut T, f: F) {
+	ptr::write(dest, f(ptr::read(dest)));
+}
+
+/// Temporarily takes ownership of a value at a mutable location, and replace it with a new value
+/// based on the old one. Lets the closure return a custom value as well.
+///
+/// We move out of the reference temporarily, to apply a closure `f`, returning a new value, which
+/// is then placed at the original value's location.
+///
+/// This is effectively the same function as [`replace_with`], but it lets the closure return a
+/// custom value as well.
+///
+/// # An important note
+///
+/// On panic (or to be more precise, unwinding) of the closure `f`, `default` will be called to
+/// provide a replacement value. `default` should not panic – doing so will constitute a double
+/// panic and will most likely abort the process.
+///
+/// # Example
+///
+/// ```
+/// # use replace_with::*;
+///
+/// fn take<T>(option: &mut Option<T>) -> Option<T> {
+///     replace_with_and_return(option, || None, |option| (option, None))
+/// }
+///
+/// let mut opt = Some(3);
+/// assert_eq!(take(&mut opt), Some(3));
+/// assert_eq!(take(&mut opt), None);
+/// ```
+#[inline]
+pub fn replace_with_and_return<T, U, D: FnOnce() -> T, F: FnOnce(T) -> (U, T)>(
+	dest: &mut T, default: D, f: F,
+) -> U {
+	unsafe {
+		let old = ptr::read(dest);
+		let (res, new) = on_unwind(move || f(old), || ptr::write(dest, default()));
+		ptr::write(dest, new);
+		res
+	}
+}
+
+/// Temporarily takes ownership of a value at a mutable location, and replace it with a new value
+/// based on the old one. Replaces with [`Default::default()`] on panic.
+/// Lets the closure return a custom value as well.
+///
+/// We move out of the reference temporarily, to apply a closure `f`, returning a new value, which
+/// is then placed at the original value's location.
+///
+/// This is effectively the same function as [`replace_with_or_default`], but it lets the closure
+/// return a custom value as well.
+///
+/// # An important note
+///
+/// On panic (or to be more precise, unwinding) of the closure `f`, `T::default()` will be called to
+/// provide a replacement value. `T::default()` should not panic – doing so will constitute a double
+/// panic and will most likely abort the process.
+///
+/// Equivalent to `replace_with_and_return(dest, T::default, f)`.
+///
+/// # Example
+///
+/// ```
+/// # use replace_with::*;
+///
+/// fn take<T>(option: &mut Option<T>) -> Option<T> {
+///     replace_with_or_default_and_return(option, |option| (option, None))
+/// }
+/// ```
+#[inline]
+pub fn replace_with_or_default_and_return<T: Default, U, F: FnOnce(T) -> (U, T)>(
+	dest: &mut T, f: F,
+) -> U {
+	replace_with_and_return(dest, T::default, f)
+}
+
+/// Temporarily takes ownership of a value at a mutable location, and replace it with a new value
+/// based on the old one. Aborts on panic. Lets the closure return a custom value as well.
+///
+/// We move out of the reference temporarily, to apply a closure `f`, returning a new value, which
+/// is then placed at the original value's location.
+///
+/// This is effectively the same function as [`replace_with_or_abort`], but it lets the closure
+/// return a custom value as well.
+///
+/// # An important note
+///
+/// On panic (or to be more precise, unwinding) of the closure `f`, the process will **abort** to
+/// avoid returning control while `dest` is in a potentially invalid state.
+///
+/// If this behaviour is undesirable, use [`replace_with_and_return`] or
+/// [`replace_with_or_default_and_return`] instead.
+///
+/// Equivalent to `replace_with_and_return(dest, || process::abort(), f)`.
+///
+/// # Example
+///
+/// ```
+/// # use replace_with::*;
+///
+/// fn take<T>(option: &mut Option<T>) -> Option<T> {
+///     replace_with_or_abort_and_return(option, |option| (option, None))
+/// }
+/// ```
+#[inline]
+#[cfg(feature = "std")]
+pub fn replace_with_or_abort_and_return<T, U, F: FnOnce(T) -> (U, T)>(dest: &mut T, f: F) -> U {
+	replace_with_and_return(dest, || std::process::abort(), f)
+}
+
+#[inline]
+#[cfg(all(not(feature = "std"), feature = "nightly"))]
+pub fn replace_with_or_abort_and_return<T, U, F: FnOnce(T) -> (U, T)>(dest: &mut T, f: F) -> U {
+	replace_with_and_return(dest, || unsafe { std::intrinsics::abort() }, f)
+}
+
+/// Temporarily takes ownership of a value at a mutable location, and replace it with a new value
+/// based on the old one. Aborts on panic. Lets the closure return a custom value as well.
+///
+/// We move out of the reference temporarily, to apply a closure `f`, returning a new value, which
+/// is then placed at the original value's location.
+///
+/// This is effectively the same function as [`replace_with_or_abort_unchecked`], but it lets the
+/// closure return a custom value as well.
+///
+/// # An important note
+///
+/// On panic (or to be more precise, unwinding) of the closure `f`, the process will **abort** to
+/// avoid returning control while `dest` is in a potentially invalid state.
+///
+/// Unlike for `replace_with_or_abort()` users of `replace_with_or_abort_unchecked()` are expected
+/// to have `features = ["panic_abort", …]` defined in `Cargo.toml`
+/// and `panic = "abort"` defined in their profile for it to behave semantically correct:
+///
+/// ```toml
+/// # Cargo.toml
+///
+/// [profile.debug]
+/// panic = "abort"
+///
+/// [profile.release]
+/// panic = "abort"
+/// ```
+///
+/// # Safety
+///
+/// It is crucial to only ever use this function having defined `panic = "abort"`, or else bad
+/// things may happen. It's *up to you* to uphold this invariant!
+///
+/// If this behaviour is undesirable, use [`replace_with_and_return`] or
+/// [`replace_with_or_default_and_return`].
+///
+/// Equivalent to `replace_with_and_return(dest, || process::abort(), f)`.
+///
+/// # Example
+///
+/// ```
+/// # use replace_with::*;
+///
+/// unsafe fn take<T>(option: &mut Option<T>) -> Option<T> {
+///     replace_with_or_abort_and_return_unchecked(option, |option| (option, None))
+/// }
+/// ```
+#[inline]
+#[cfg(feature = "std")]
+#[cfg(feature = "panic_abort")]
+pub unsafe fn replace_with_or_abort_and_return_unchecked<T, U, F: FnOnce(T) -> (U, T)>(
+	dest: &mut T, f: F,
+) -> U {
+	let (res, new) = f(ptr::read(dest));
+	ptr::write(dest, new);
+	res
+}
+
+#[cfg(test)]
+mod test {
+	// These functions copied from https://github.com/Sgeo/take_mut/blob/1bd70d842c6febcd16ec1fe3a954a84032b89f52/src/lib.rs#L102-L147
+
+	// Copyright (c) 2016 Sgeo
+
+	// Permission is hereby granted, free of charge, to any person obtaining a copy
+	// of this software and associated documentation files (the "Software"), to deal
+	// in the Software without restriction, including without limitation the rights
+	// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+	// copies of the Software, and to permit persons to whom the Software is
+	// furnished to do so, subject to the following conditions:
+
+	// The above copyright notice and this permission notice shall be included in all
+	// copies or substantial portions of the Software.
+
+	// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+	// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+	// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+	// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+	// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+	// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+	// SOFTWARE.
+
+	use super::*;
+
+	#[test]
+	fn it_works_recover() {
+		#[derive(PartialEq, Eq, Debug)]
+		enum Foo {
+			A,
+			B,
+		};
+		impl Drop for Foo {
+			#[cfg(feature = "std")]
+			fn drop(&mut self) {
+				match *self {
+					Foo::A => println!("Foo::A dropped"),
+					Foo::B => println!("Foo::B dropped"),
+				}
+			}
+
+			#[cfg(not(feature = "std"))]
+			fn drop(&mut self) {
+				match *self {
+					Foo::A | Foo::B => (),
+				}
+			}
+		}
+		let mut quax = Foo::A;
+		replace_with(
+			&mut quax,
+			|| Foo::A,
+			|f| {
+				drop(f);
+				Foo::B
+			},
+		);
+		assert_eq!(&quax, &Foo::B);
+
+		let n = replace_with_and_return(
+			&mut quax,
+			|| Foo::B,
+			|f| {
+				drop(f);
+				(3, Foo::A)
+			},
+		);
+		assert_eq!(n, 3);
+		assert_eq!(&quax, &Foo::A);
+	}
+
+	#[cfg(all(feature = "std", not(miri)))] // https://github.com/rust-lang/miri/issues/658
+	#[test]
+	fn it_works_recover_panic() {
+		use std::panic;
+
+		#[derive(PartialEq, Eq, Debug)]
+		enum Foo {
+			A,
+			B,
+			C,
+		};
+		impl Drop for Foo {
+			fn drop(&mut self) {
+				match *self {
+					Foo::A => println!("Foo::A dropped"),
+					Foo::B => println!("Foo::B dropped"),
+					Foo::C => println!("Foo::C dropped"),
+				}
+			}
+		}
+		let mut quax = Foo::A;
+
+		let res = panic::catch_unwind(panic::AssertUnwindSafe(|| {
+			replace_with(
+				&mut quax,
+				|| Foo::C,
+				|f| {
+					drop(f);
+					panic!("panic");
+					#[allow(unreachable_code)]
+					Foo::B
+				},
+			);
+		}));
+
+		assert!(res.is_err());
+		assert_eq!(&quax, &Foo::C);
+	}
+}