publish 1.7.2

CHANGELOG.md

@@ -1,9 +1,12 @@
 # Changelog
 
+## 1.7.2
+
+- Improve code size when using parking_lot feature.
+
 ## 1.7.1
 
 - Fix `race::OnceBox<T>` to also impl `Default` even if `T` doesn't impl `Default`.
-- Improve code size.
 
 ## 1.7.0
 

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "once_cell"
-version = "1.7.1"
+version = "1.7.2"
 authors = ["Aleksey Kladov <aleksey.kladov@gmail.com>"]
 license = "MIT OR Apache-2.0"
 edition = "2018"

src/imp_pl.rs

@@ -7,6 +7,8 @@ use std::{
 
 use parking_lot::Mutex;
 
+use crate::take_unchecked;
+
 pub(crate) struct OnceCell<T> {
     mutex: Mutex<()>,
     is_initialized: AtomicBool,
@@ -58,7 +60,7 @@ impl<T> OnceCell<T> {
             //   but that is more complicated
             // - finally, if it returns Ok, we store the value and store the flag with
             //   `Release`, which synchronizes with `Acquire`s.
-            let f = f.take().unwrap_or_else(|| unsafe { hint::unreachable_unchecked() });
+            let f = unsafe { take_unchecked(&mut f) };
             match f() {
                 Ok(value) => unsafe {
                     // Safe b/c we have a unique access and no panic may happen

src/imp_std.rs

@@ -12,6 +12,8 @@ use std::{
     thread::{self, Thread},
 };
 
+use crate::take_unchecked;
+
 #[derive(Debug)]
 pub(crate) struct OnceCell<T> {
     // This `state` word is actually an encoded version of just a pointer to a
@@ -89,7 +91,7 @@ impl<T> OnceCell<T> {
         let mut res: Result<(), E> = Ok(());
         let slot: *mut Option<T> = self.value.get();
         initialize_inner(&self.state_and_queue, &mut || {
-            let f = f.take().unwrap_or_else(|| unsafe { unreachable_unchecked() });
+            let f = unsafe { take_unchecked(&mut f) };
             match f() {
                 Ok(value) => {
                     unsafe { *slot = Some(value) };

src/lib.rs

@@ -1067,3 +1067,14 @@ pub mod sync {
 
 #[cfg(feature = "race")]
 pub mod race;
+
+#[cfg(feature = "std")]
+unsafe fn take_unchecked<T>(val: &mut Option<T>) -> T {
+    match val.take() {
+        Some(it) => it,
+        None => {
+            debug_assert!(false);
+            std::hint::unreachable_unchecked()
+        }
+    }
+}