Move OsRng definition to rand::rngs

Also removes std, os_rng features from rand_core

Author: dhardy

Cargo.toml

@@ -34,13 +34,13 @@ serde = ["dep:serde", "rand_core/serde"]
 
 # Option (enabled by default): without "std" rand uses libcore; this option
 # enables functionality expected to be available on a standard platform.
-std = ["rand_core/std", "alloc"]
+std = ["alloc", "getrandom?/std"]
 
 # Option: "alloc" enables support for Vec and Box when not using "std"
 alloc = []
 
 # Option: enable OsRng
-os_rng = ["rand_core/os_rng"]
+os_rng = ["dep:getrandom"]
 
 # Option (requires nightly Rust): experimental SIMD support
 simd_support = []
@@ -83,6 +83,7 @@ rand_core = { path = "rand_core", version = "0.9.0", default-features = false }
 log = { version = "0.4.4", optional = true }
 serde = { version = "1.0.103", features = ["derive"], optional = true }
 chacha20 = { version = "=0.10.0-rc.2", default-features = false, features = ["rng"], optional = true }
+getrandom = { version = "0.3.0", optional = true }
 
 [dev-dependencies]
 rand_pcg = { path = "rand_pcg", version = "0.9.0" }

rand_chacha/Cargo.toml

@@ -32,5 +32,5 @@ rand = { path = "..", version = "0.10.0-rc.0" }
 
 [features]
 default = ["std"]
-std = ["ppv-lite86/std", "rand_core/std"]
+std = ["ppv-lite86/std"]
 serde = ["dep:serde"]

rand_core/Cargo.toml

@@ -25,10 +25,7 @@ rustdoc-args = ["--generate-link-to-definition"]
 all-features = true
 
 [features]
-std = ["getrandom?/std"]
-os_rng = ["dep:getrandom"]
 serde = ["dep:serde"] # enables serde for BlockRng wrapper
 
 [dependencies]
 serde = { version = "1", features = ["derive"], optional = true }
-getrandom = { version = "0.3.0", optional = true }

rand_core/src/lib.rs

@@ -36,18 +36,10 @@
 #![cfg_attr(docsrs, feature(doc_cfg))]
 #![no_std]
 
-#[cfg(feature = "std")]
-extern crate std;
-
 use core::{fmt, ops::DerefMut};
 
 pub mod block;
 pub mod le;
-#[cfg(feature = "os_rng")]
-mod os;
-
-#[cfg(feature = "os_rng")]
-pub use os::{OsError, OsRng};
 
 /// Implementation-level interface for RNGs
 ///
@@ -168,6 +160,8 @@ where
 /// An optional property of CSPRNGs is backtracking resistance: if the CSPRNG's
 /// state is revealed, it will not be computationally-feasible to reconstruct
 /// prior output values. This property is not required by `CryptoRng`.
+///
+/// [`OsRng`]: https://docs.rs/rand/latest/rand/rngs/struct.OsRng.html
 pub trait CryptoRng: RngCore {}
 
 impl<T: DerefMut> CryptoRng for T where T::Target: CryptoRng {}
@@ -184,6 +178,8 @@ impl<T: DerefMut> CryptoRng for T where T::Target: CryptoRng {}
 /// An implementation of this trait may be made compatible with code requiring
 /// an [`RngCore`] through [`TryRngCore::unwrap_err`]. The resulting RNG will
 /// panic in case the underlying fallible RNG yields an error.
+///
+/// [`OsRng`]: https://docs.rs/rand/latest/rand/rngs/struct.OsRng.html
 pub trait TryRngCore {
     /// The type returned in the event of a RNG error.
     type Error: fmt::Debug + fmt::Display;
@@ -246,6 +242,8 @@ impl<R: RngCore + ?Sized> TryRngCore for R {
 /// `default()` instances are themselves secure generators: for example if the
 /// implementing type is a stateless interface over a secure external generator
 /// (like [`OsRng`]) or if the `default()` instance uses a strong, fresh seed.
+///
+/// [`OsRng`]: https://docs.rs/rand/latest/rand/rngs/struct.OsRng.html
 pub trait TryCryptoRng: TryRngCore {}
 
 impl<R: CryptoRng + ?Sized> TryCryptoRng for R {}

src/rngs/mod.rs

@@ -110,6 +110,9 @@ mod std;
 #[cfg(feature = "thread_rng")]
 pub(crate) mod thread;
 
+#[cfg(feature = "os_rng")]
+mod os;
+
 #[cfg(feature = "small_rng")]
 pub use self::small::SmallRng;
 #[cfg(feature = "small_rng")]
@@ -126,4 +129,4 @@ pub use self::thread::ThreadRng;
 pub use chacha20::{ChaCha8Rng, ChaCha12Rng, ChaCha20Rng};
 
 #[cfg(feature = "os_rng")]
-pub use rand_core::OsRng;
+pub use os::{OsError, OsRng};

rand_core/src/os.rs renamed to src/rngs/os.rs

@@ -35,7 +35,7 @@ use crate::{TryCryptoRng, TryRngCore};
 ///
 /// # Usage example
 /// ```
-/// use rand_core::{TryRngCore, OsRng};
+/// use rand::{TryRngCore, rngs::OsRng};
 ///
 /// let mut key = [0u8; 16];
 /// OsRng.try_fill_bytes(&mut key).unwrap();

src/rngs/thread.rs

@@ -13,12 +13,9 @@ use std::fmt;
 use std::rc::Rc;
 use std::thread_local;
 
+use super::{OsError, OsRng, ReseedingRng, std::Core};
 use rand_core::{CryptoRng, RngCore};
 
-use super::std::Core;
-use crate::rngs::OsRng;
-use crate::rngs::ReseedingRng;
-
 // Rationale for using `UnsafeCell` in `ThreadRng`:
 //
 // Previously we used a `RefCell`, with an overhead of ~15%. There will only
@@ -100,7 +97,7 @@ impl ThreadRng {
     /// Immediately reseed the generator
     ///
     /// This discards any remaining random data in the cache.
-    pub fn reseed(&mut self) -> Result<(), rand_core::OsError> {
+    pub fn reseed(&mut self) -> Result<(), OsError> {
         // SAFETY: We must make sure to stop using `rng` before anyone else
         // creates another mutable reference
         let rng = unsafe { &mut *self.rng.get() };