Linux/Android: Use once_cell::race::OnceBool.

After this, `lazy` is only used by netbsd. (`once_cell::race` doesn't
have a `OncePtr`.)

Author: briansmith

Cargo.toml

@@ -15,7 +15,7 @@ exclude = [".*"]
 cfg-if = "1"
 once_cell = { version = "1.19.0", default-features = false, optional = true }
 
-[target.'cfg(all(target_arch = "x86_64", target_env = "sgx"))'.dependencies]
+[target.'cfg(any(target_os = "android", target_os = "linux", all(target_arch = "x86_64", target_env = "sgx")))'.dependencies]
 once_cell = { version = "1.19.0", default-features = false, features = ["race"] }
 
 # When built as part of libstd

src/lazy.rs

@@ -55,19 +55,6 @@ impl LazyUsize {
     }
 }
 
-// Identical to LazyUsize except with bool instead of usize.
-pub(crate) struct LazyBool(LazyUsize);
-
-impl LazyBool {
-    pub const fn new() -> Self {
-        Self(LazyUsize::new())
-    }
-
-    pub fn unsync_init(&self, init: impl FnOnce() -> bool) -> bool {
-        self.0.unsync_init(|| usize::from(init())) != 0
-    }
-}
-
 // This structure represents a lazily initialized static pointer value.
 ///
 /// It's intended to be used for weak linking of a C function that may

src/lib.rs

@@ -216,7 +216,6 @@ use crate::util::{slice_as_uninit_mut, slice_assume_init_mut};
 use core::mem::MaybeUninit;
 
 mod error;
-mod lazy;
 mod util;
 // To prevent a breaking change when targets are added, we always export the
 // register_custom_getrandom macro, so old Custom RNG crates continue to build.
@@ -308,6 +307,7 @@ cfg_if! {
         mod util_libc;
         #[path = "solaris.rs"] mod imp;
     } else if #[cfg(target_os = "netbsd")] {
+        mod lazy;
         mod util_libc;
         #[path = "netbsd.rs"] mod imp;
     } else if #[cfg(target_os = "fuchsia")] {

src/linux_android_with_fallback.rs

@@ -1,11 +1,12 @@
 //! Implementation for Linux / Android with `/dev/urandom` fallback
-use crate::{lazy::LazyBool, linux_android, use_file, util_libc::last_os_error, Error};
+use crate::{linux_android, use_file, util_libc::last_os_error, Error};
 use core::mem::MaybeUninit;
+use once_cell::race::OnceBool;
 
 pub fn getrandom_inner(dest: &mut [MaybeUninit<u8>]) -> Result<(), Error> {
     // getrandom(2) was introduced in Linux 3.17
-    static HAS_GETRANDOM: LazyBool = LazyBool::new();
-    if HAS_GETRANDOM.unsync_init(is_getrandom_available) {
+    static HAS_GETRANDOM: OnceBool = OnceBool::new();
+    if HAS_GETRANDOM.get_or_init(is_getrandom_available) {
         linux_android::getrandom_inner(dest)
     } else {
         use_file::getrandom_inner(dest)