1 files changed, 150 insertions, 0 deletions
diff --git a/third_party/rust/rand/src/rngs/adapter/read.rs b/third_party/rust/rand/src/rngs/adapter/read.rs
new file mode 100644
index 0000000000..25a9ca7fca
--- /dev/null
+++ b/third_party/rust/rand/src/rngs/adapter/read.rs
@@ -0,0 +1,150 @@
+// Copyright 2018 Developers of the Rand project.
+// Copyright 2013 The Rust Project Developers.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//! A wrapper around any Read to treat it as an RNG.
+
+#![allow(deprecated)]
+
+use std::fmt;
+use std::io::Read;
+
+use rand_core::{impls, Error, RngCore};
+
+
+/// An RNG that reads random bytes straight from any type supporting
+/// [`std::io::Read`], for example files.
+///
+/// This will work best with an infinite reader, but that is not required.
+///
+/// This can be used with `/dev/urandom` on Unix but it is recommended to use
+/// [`OsRng`] instead.
+///
+/// # Panics
+///
+/// `ReadRng` uses [`std::io::Read::read_exact`], which retries on interrupts.
+/// All other errors from the underlying reader, including when it does not
+/// have enough data, will only be reported through [`try_fill_bytes`].
+/// The other [`RngCore`] methods will panic in case of an error.
+///
+/// [`OsRng`]: crate::rngs::OsRng
+/// [`try_fill_bytes`]: RngCore::try_fill_bytes
+#[derive(Debug)]
+#[deprecated(since="0.8.4", note="removal due to lack of usage")]
+pub struct ReadRng<R> {
+    reader: R,
+}
+
+impl<R: Read> ReadRng<R> {
+    /// Create a new `ReadRng` from a `Read`.
+    pub fn new(r: R) -> ReadRng<R> {
+        ReadRng { reader: r }
+    }
+}
+
+impl<R: Read> RngCore for ReadRng<R> {
+    fn next_u32(&mut self) -> u32 {
+        impls::next_u32_via_fill(self)
+    }
+
+    fn next_u64(&mut self) -> u64 {
+        impls::next_u64_via_fill(self)
+    }
+
+    fn fill_bytes(&mut self, dest: &mut [u8]) {
+        self.try_fill_bytes(dest).unwrap_or_else(|err| {
+            panic!(
+                "reading random bytes from Read implementation failed; error: {}",
+                err
+            )
+        });
+    }
+
+    fn try_fill_bytes(&mut self, dest: &mut [u8]) -> Result<(), Error> {
+        if dest.is_empty() {
+            return Ok(());
+        }
+        // Use `std::io::read_exact`, which retries on `ErrorKind::Interrupted`.
+        self.reader
+            .read_exact(dest)
+            .map_err(|e| Error::new(ReadError(e)))
+    }
+}
+
+/// `ReadRng` error type
+#[derive(Debug)]
+#[deprecated(since="0.8.4")]
+pub struct ReadError(std::io::Error);
+
+impl fmt::Display for ReadError {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "ReadError: {}", self.0)
+    }
+}
+
+impl std::error::Error for ReadError {
+    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
+        Some(&self.0)
+    }
+}
+
+
+#[cfg(test)]
+mod test {
+    use std::println;
+
+    use super::ReadRng;
+    use crate::RngCore;
+
+    #[test]
+    fn test_reader_rng_u64() {
+        // transmute from the target to avoid endianness concerns.
+        #[rustfmt::skip]
+        let v = [0u8, 0, 0, 0, 0, 0, 0, 1,
+                 0,   4, 0, 0, 3, 0, 0, 2,
+                 5,   0, 0, 0, 0, 0, 0, 0];
+        let mut rng = ReadRng::new(&v[..]);
+
+        assert_eq!(rng.next_u64(), 1 << 56);
+        assert_eq!(rng.next_u64(), (2 << 56) + (3 << 32) + (4 << 8));
+        assert_eq!(rng.next_u64(), 5);
+    }
+
+    #[test]
+    fn test_reader_rng_u32() {
+        let v = [0u8, 0, 0, 1, 0, 0, 2, 0, 3, 0, 0, 0];
+        let mut rng = ReadRng::new(&v[..]);
+
+        assert_eq!(rng.next_u32(), 1 << 24);
+        assert_eq!(rng.next_u32(), 2 << 16);
+        assert_eq!(rng.next_u32(), 3);
+    }
+
+    #[test]
+    fn test_reader_rng_fill_bytes() {
+        let v = [1u8, 2, 3, 4, 5, 6, 7, 8];
+        let mut w = [0u8; 8];
+
+        let mut rng = ReadRng::new(&v[..]);
+        rng.fill_bytes(&mut w);
+
+        assert!(v == w);
+    }
+
+    #[test]
+    fn test_reader_rng_insufficient_bytes() {
+        let v = [1u8, 2, 3, 4, 5, 6, 7, 8];
+        let mut w = [0u8; 9];
+
+        let mut rng = ReadRng::new(&v[..]);
+
+        let result = rng.try_fill_bytes(&mut w);
+        assert!(result.is_err());
+        println!("Error: {}", result.unwrap_err());
+    }
+}