Remove dependence on rand_jitter

This is a breaking change for anyone using rngs::JitterRng;
such users should switch to rand_jitter::JitterRng.

Author: dhardy

Cargo.toml

@@ -22,7 +22,7 @@ appveyor = { repository = "rust-random/rand" }
 [features]
 default = ["std"] # without "std" rand uses libcore
 nightly = ["simd_support"] # enables all features requiring nightly rust
-std = ["rand_core/std", "alloc", "getrandom", "rand_jitter/std"]
+std = ["rand_core/std", "alloc", "getrandom"]
 alloc = ["rand_core/alloc"]  # enables Vec and Box support (without std)
 i128_support = [] # enables i128 and u128 support
 simd_support = ["packed_simd"] # enables SIMD support
@@ -49,7 +49,6 @@ members = [
 [dependencies]
 rand_core = { path = "rand_core", version = "0.4" }
 rand_pcg = { path = "rand_pcg", version = "0.1" }
-rand_jitter = { path = "rand_jitter", version = "0.1" }
 rand_hc = { path = "rand_hc", version = "0.1" }
 getrandom = { version = "0.1", optional = true }
 log = { version = "0.4", optional = true }

benches/generators.rs

@@ -25,7 +25,7 @@ use test::{black_box, Bencher};
 
 use rand::prelude::*;
 use rand::rngs::adapter::ReseedingRng;
-use rand::rngs::{OsRng, JitterRng};
+use rand::rngs::OsRng;
 use rand_isaac::{IsaacRng, Isaac64Rng};
 use rand_chacha::ChaChaRng;
 use rand_hc::{Hc128Rng, Hc128Core};
@@ -129,17 +129,6 @@ gen_uint!(gen_u64_std, u64, StdRng::from_entropy());
 gen_uint!(gen_u64_small, u64, SmallRng::from_entropy());
 gen_uint!(gen_u64_os, u64, OsRng::new().unwrap());
 
-// Do not test JitterRng like the others by running it RAND_BENCH_N times per,
-// measurement, because it is way too slow. Only run it once.
-#[bench]
-fn gen_u64_jitter(b: &mut Bencher) {
-    let mut rng = JitterRng::new().unwrap();
-    b.iter(|| {
-        rng.gen::<u64>()
-    });
-    b.bytes = size_of::<u64>() as u64;
-}
-
 macro_rules! init_gen {
     ($fnn:ident, $gen:ident) => {
         #[bench]
@@ -170,13 +159,6 @@ init_gen!(init_isaac, IsaacRng);
 init_gen!(init_isaac64, Isaac64Rng);
 init_gen!(init_chacha, ChaChaRng);
 
-#[bench]
-fn init_jitter(b: &mut Bencher) {
-    b.iter(|| {
-        JitterRng::new().unwrap()
-    });
-}
-
 
 const RESEEDING_THRESHOLD: u64 = 1024*1024*1024; // something high enough to get
                                                  // deterministic measurements

src/lib.rs

@@ -58,7 +58,6 @@
 
 #[cfg(feature="simd_support")] extern crate packed_simd;
 
-extern crate rand_jitter;
 #[cfg(feature = "getrandom")]
 extern crate getrandom;
 
@@ -480,35 +479,16 @@ impl_as_byte_slice_arrays!(!div 4096, N,N,N,N,N,N,N,);
 /// [`OsRng`]: rngs::OsRng
 #[cfg(feature="std")]
 pub trait FromEntropy: SeedableRng {
-    /// Creates a new instance, automatically seeded with fresh entropy.
+    /// Creates a new instance of the RNG seeded from [`OsRng`].
     ///
-    /// Normally this will use `OsRng`, but if that fails `JitterRng` will be
-    /// used instead. Both should be suitable for cryptography. It is possible
-    /// that both entropy sources will fail though unlikely; failures would
-    /// almost certainly be platform limitations or build issues, i.e. most
-    /// applications targetting PC/mobile platforms should not need to worry
-    /// about this failing.
+    /// This method is equivalent to `SeedableRng::from_rng(OsRng).unwrap()`.
     ///
     /// # Panics
     ///
-    /// If all entropy sources fail this will panic. If you need to handle
-    /// errors, use the following code, equivalent aside from error handling:
-    ///
-    /// ```
-    /// # use rand::Error;
-    /// use rand::prelude::*;
-    /// use rand::rngs::OsRng;
-    ///
-    /// # fn try_inner() -> Result<(), Error> {
-    /// // This uses StdRng, but is valid for any R: SeedableRng
-    /// let mut rng = StdRng::from_rng(OsRng)?;
-    ///
-    /// println!("random number: {}", rng.gen_range(1, 10));
-    /// # Ok(())
-    /// # }
-    ///
-    /// # try_inner().unwrap()
-    /// ```
+    /// If [`OsRng`] is unable to obtain secure entropy this method will panic.
+    /// It is also possible for an RNG overriding the [`SeedableRng::from_rng`]
+    /// method to cause a panic. Both causes are extremely unlikely to occur;
+    /// most users need not worry about this.
     fn from_entropy() -> Self;
 }
 

src/rngs/mod.rs

@@ -24,8 +24,8 @@
 //!
 //! Generally the operating system will collect some entropy, remove bias, and
 //! use that to seed its own PRNG; [`OsRng`] provides an interface to this.
-//! [`JitterRng`] is an entropy collector included with Rand that measures
-//! jitter in the CPU execution time, and jitter in memory access time.
+//! Some alternatives are available although not normally required; see the
+//! [`rdrand`] and [`rand_jitter`] crates.
 //!
 //! ## Pseudo-random number generators
 //!
@@ -136,11 +136,12 @@
 //! [`SmallRng`]: rngs::SmallRng
 //! [`StdRng`]: rngs::StdRng
 //! [`ThreadRng`]: rngs::ThreadRng
-//! [`JitterRng`]: rngs::JitterRng
 //! [`mock::StepRng`]: rngs::mock::StepRng
 //! [`adapter::ReadRng`]: rngs::adapter::ReadRng
 //! [`adapter::ReseedingRng`]: rngs::adapter::ReseedingRng
 //! [`ChaChaRng`]: ../../rand_chacha/struct.ChaChaRng.html
+//! [`rdrand`]: https://crates.io/crates/rdrand
+//! [`rand_jitter`]: https://crates.io/crates/rand_jitter
 
 pub mod adapter;
 
@@ -151,8 +152,6 @@ mod small;
 mod std;
 #[cfg(feature="std")] pub(crate) mod thread;
 
-
-pub use rand_jitter::{JitterRng, TimerError};
 #[allow(deprecated)]
 #[cfg(feature="std")] pub use self::entropy::EntropyRng;