Import getrandom-0.1.14
Change-Id: I2e27b76bb8b37119712eeda01f94641a77cce5fd
diff --git a/src/wasm32_stdweb.rs b/src/wasm32_stdweb.rs
new file mode 100644
index 0000000..6e5e78a
--- /dev/null
+++ b/src/wasm32_stdweb.rs
@@ -0,0 +1,114 @@
+// 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 WASM via stdweb
+extern crate std;
+
+use core::mem;
+
+use stdweb::js;
+use stdweb::unstable::TryInto;
+use stdweb::web::error::Error as WebError;
+
+use crate::error::{STDWEB_NO_RNG, STDWEB_RNG_FAILED};
+use crate::Error;
+use std::sync::Once;
+
+#[derive(Clone, Copy, Debug)]
+enum RngSource {
+ Browser,
+ Node,
+}
+
+pub fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
+ assert_eq!(mem::size_of::<usize>(), 4);
+ static ONCE: Once = Once::new();
+ static mut RNG_SOURCE: Result<RngSource, Error> = Ok(RngSource::Node);
+
+ // SAFETY: RNG_SOURCE is only written once, before being read.
+ ONCE.call_once(|| unsafe {
+ RNG_SOURCE = getrandom_init();
+ });
+ getrandom_fill(unsafe { RNG_SOURCE }?, dest)
+}
+
+fn getrandom_init() -> Result<RngSource, Error> {
+ let result = js! {
+ try {
+ if (
+ typeof self === "object" &&
+ typeof self.crypto === "object" &&
+ typeof self.crypto.getRandomValues === "function"
+ ) {
+ return { success: true, ty: 1 };
+ }
+
+ if (typeof require("crypto").randomBytes === "function") {
+ return { success: true, ty: 2 };
+ }
+
+ return { success: false, error: new Error("not supported") };
+ } catch(err) {
+ return { success: false, error: err };
+ }
+ };
+
+ if js! { return @{ result.as_ref() }.success } == true {
+ let ty = js! { return @{ result }.ty };
+
+ if ty == 1 {
+ Ok(RngSource::Browser)
+ } else if ty == 2 {
+ Ok(RngSource::Node)
+ } else {
+ unreachable!()
+ }
+ } else {
+ let _err: WebError = js! { return @{ result }.error }.try_into().unwrap();
+ error!("getrandom unavailable: {}", _err);
+ Err(STDWEB_NO_RNG)
+ }
+}
+
+fn getrandom_fill(source: RngSource, dest: &mut [u8]) -> Result<(), Error> {
+ for chunk in dest.chunks_mut(65536) {
+ let len = chunk.len() as u32;
+ let ptr = chunk.as_mut_ptr() as i32;
+
+ let result = match source {
+ RngSource::Browser => js! {
+ try {
+ let array = new Uint8Array(@{ len });
+ self.crypto.getRandomValues(array);
+ HEAPU8.set(array, @{ ptr });
+
+ return { success: true };
+ } catch(err) {
+ return { success: false, error: err };
+ }
+ },
+ RngSource::Node => js! {
+ try {
+ let bytes = require("crypto").randomBytes(@{ len });
+ HEAPU8.set(new Uint8Array(bytes), @{ ptr });
+
+ return { success: true };
+ } catch(err) {
+ return { success: false, error: err };
+ }
+ },
+ };
+
+ if js! { return @{ result.as_ref() }.success } != true {
+ let _err: WebError = js! { return @{ result }.error }.try_into().unwrap();
+ error!("getrandom failed: {}", _err);
+ return Err(STDWEB_RNG_FAILED);
+ }
+ }
+ Ok(())
+}