diff --git a/library/alloc/src/collections/btree/mem.rs b/library/alloc/src/collections/btree/mem.rs new file mode 100644 index 0000000000000..5e7d9fa3f91ba --- /dev/null +++ b/library/alloc/src/collections/btree/mem.rs @@ -0,0 +1,34 @@ +use core::intrinsics; +use core::mem; +use core::ptr; + +/// This replaces the value behind the `v` unique reference by calling the +/// relevant function. +/// +/// If a panic occurs in the `change` closure, the entire process will be aborted. +#[inline] +pub fn take_mut(v: &mut T, change: impl FnOnce(T) -> T) { + replace(v, |value| (change(value), ())) +} + +/// This replaces the value behind the `v` unique reference by calling the +/// relevant function, and returns a result obtained along the way. +/// +/// If a panic occurs in the `change` closure, the entire process will be aborted. +#[inline] +pub fn replace(v: &mut T, change: impl FnOnce(T) -> (T, R)) -> R { + struct PanicGuard; + impl Drop for PanicGuard { + fn drop(&mut self) { + intrinsics::abort() + } + } + let guard = PanicGuard; + let value = unsafe { ptr::read(v) }; + let (new_value, ret) = change(value); + unsafe { + ptr::write(v, new_value); + } + mem::forget(guard); + ret +} diff --git a/library/alloc/src/collections/btree/mod.rs b/library/alloc/src/collections/btree/mod.rs index 3f475898e0fbf..4c07795bd70cd 100644 --- a/library/alloc/src/collections/btree/mod.rs +++ b/library/alloc/src/collections/btree/mod.rs @@ -1,5 +1,6 @@ mod borrow; pub mod map; +mod mem; mod merge_iter; mod navigate; mod node; diff --git a/library/alloc/src/collections/btree/navigate.rs b/library/alloc/src/collections/btree/navigate.rs index 55ce7d275464e..de78148fc82be 100644 --- a/library/alloc/src/collections/btree/navigate.rs +++ b/library/alloc/src/collections/btree/navigate.rs @@ -1,7 +1,5 @@ use core::borrow::Borrow; use core::cmp::Ordering; -use core::intrinsics; -use core::mem; use core::ops::Bound::{Excluded, Included, Unbounded}; use core::ops::RangeBounds; use core::ptr; @@ -304,37 +302,6 @@ macro_rules! def_next_kv_uncheched_dealloc { def_next_kv_uncheched_dealloc! {unsafe fn next_kv_unchecked_dealloc: right_kv} def_next_kv_uncheched_dealloc! {unsafe fn next_back_kv_unchecked_dealloc: left_kv} -/// This replaces the value behind the `v` unique reference by calling the -/// relevant function. -/// -/// If a panic occurs in the `change` closure, the entire process will be aborted. -#[inline] -fn take_mut(v: &mut T, change: impl FnOnce(T) -> T) { - replace(v, |value| (change(value), ())) -} - -/// This replaces the value behind the `v` unique reference by calling the -/// relevant function, and returns a result obtained along the way. -/// -/// If a panic occurs in the `change` closure, the entire process will be aborted. -#[inline] -fn replace(v: &mut T, change: impl FnOnce(T) -> (T, R)) -> R { - struct PanicGuard; - impl Drop for PanicGuard { - fn drop(&mut self) { - intrinsics::abort() - } - } - let guard = PanicGuard; - let value = unsafe { ptr::read(v) }; - let (new_value, ret) = change(value); - unsafe { - ptr::write(v, new_value); - } - mem::forget(guard); - ret -} - impl<'a, K, V> Handle, K, V, marker::Leaf>, marker::Edge> { /// Moves the leaf edge handle to the next leaf edge and returns references to the /// key and value in between. @@ -342,7 +309,7 @@ impl<'a, K, V> Handle, K, V, marker::Leaf>, marker::Ed /// # Safety /// There must be another KV in the direction travelled. pub unsafe fn next_unchecked(&mut self) -> (&'a K, &'a V) { - replace(self, |leaf_edge| { + super::mem::replace(self, |leaf_edge| { let kv = leaf_edge.next_kv(); let kv = unsafe { unwrap_unchecked(kv.ok()) }; (kv.next_leaf_edge(), kv.into_kv()) @@ -355,7 +322,7 @@ impl<'a, K, V> Handle, K, V, marker::Leaf>, marker::Ed /// # Safety /// There must be another KV in the direction travelled. pub unsafe fn next_back_unchecked(&mut self) -> (&'a K, &'a V) { - replace(self, |leaf_edge| { + super::mem::replace(self, |leaf_edge| { let kv = leaf_edge.next_back_kv(); let kv = unsafe { unwrap_unchecked(kv.ok()) }; (kv.next_back_leaf_edge(), kv.into_kv()) @@ -370,7 +337,7 @@ impl<'a, K, V> Handle, K, V, marker::Leaf>, marker::E /// # Safety /// There must be another KV in the direction travelled. pub unsafe fn next_unchecked(&mut self) -> (&'a K, &'a mut V) { - let kv = replace(self, |leaf_edge| { + let kv = super::mem::replace(self, |leaf_edge| { let kv = leaf_edge.next_kv(); let kv = unsafe { unwrap_unchecked(kv.ok()) }; (unsafe { ptr::read(&kv) }.next_leaf_edge(), kv) @@ -385,7 +352,7 @@ impl<'a, K, V> Handle, K, V, marker::Leaf>, marker::E /// # Safety /// There must be another KV in the direction travelled. pub unsafe fn next_back_unchecked(&mut self) -> (&'a K, &'a mut V) { - let kv = replace(self, |leaf_edge| { + let kv = super::mem::replace(self, |leaf_edge| { let kv = leaf_edge.next_back_kv(); let kv = unsafe { unwrap_unchecked(kv.ok()) }; (unsafe { ptr::read(&kv) }.next_back_leaf_edge(), kv) @@ -401,7 +368,7 @@ impl<'a, K, V> Handle, K, V, marker::Leaf>, marker::Edge /// # Safety /// There must be another KV in the direction travelled. pub unsafe fn move_next_unchecked(&mut self) { - take_mut(self, |leaf_edge| { + super::mem::take_mut(self, |leaf_edge| { let kv = leaf_edge.next_kv(); let kv = unsafe { unwrap_unchecked(kv.ok()) }; kv.next_leaf_edge() @@ -423,7 +390,7 @@ impl Handle, marker::Edge> { /// call this method again subject to its safety conditions, or call counterpart /// `next_back_unchecked` subject to its safety conditions. pub unsafe fn next_unchecked(&mut self) -> (K, V) { - replace(self, |leaf_edge| { + super::mem::replace(self, |leaf_edge| { let kv = unsafe { next_kv_unchecked_dealloc(leaf_edge) }; let k = unsafe { ptr::read(kv.reborrow().into_kv().0) }; let v = unsafe { ptr::read(kv.reborrow().into_kv().1) }; @@ -444,7 +411,7 @@ impl Handle, marker::Edge> { /// call this method again subject to its safety conditions, or call counterpart /// `next_unchecked` subject to its safety conditions. pub unsafe fn next_back_unchecked(&mut self) -> (K, V) { - replace(self, |leaf_edge| { + super::mem::replace(self, |leaf_edge| { let kv = unsafe { next_back_kv_unchecked_dealloc(leaf_edge) }; let k = unsafe { ptr::read(kv.reborrow().into_kv().0) }; let v = unsafe { ptr::read(kv.reborrow().into_kv().1) };