1 files changed, 39 insertions, 0 deletions
diff --git a/rand/rand_os/src/dragonfly_haiku_emscripten.rs b/rand/rand_os/src/dragonfly_haiku_emscripten.rs
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+++ b/rand/rand_os/src/dragonfly_haiku_emscripten.rs
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+// Copyright 2018 Developers of the Rand project.
+//
+// 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.
+
+//! Implementation for DragonFly / Haiku / Emscripten
+
+use rand_core::Error;
+use super::random_device;
+use super::OsRngImpl;
+use std::fs::File;
+
+#[derive(Clone, Debug)]
+pub struct OsRng();
+
+impl OsRngImpl for OsRng {
+    fn new() -> Result<OsRng, Error> {
+        random_device::open("/dev/random", &|p| File::open(p))?;
+        Ok(OsRng())
+    }
+
+    fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error> {
+        random_device::read(dest)
+    }
+
+    #[cfg(target_os = "emscripten")]
+    fn max_chunk_size(&self) -> usize {
+        // `Crypto.getRandomValues` documents `dest` should be at most 65536
+        // bytes. `crypto.randomBytes` documents: "To minimize threadpool
+        // task length variation, partition large randomBytes requests when
+        // doing so as part of fulfilling a client request.
+        65536
+    }
+
+    fn method_str(&self) -> &'static str { "/dev/random" }
+}