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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 WASM via stdweb
use std::mem;
use stdweb::unstable::TryInto;
use stdweb::web::error::Error as WebError;
use rand_core::{Error, ErrorKind};
use super::OsRngImpl;
#[derive(Clone, Debug)]
enum OsRngMethod {
Browser,
Node
}
#[derive(Clone, Debug)]
pub struct OsRng(OsRngMethod);
impl OsRngImpl for OsRng {
fn new() -> Result<OsRng, 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(OsRng(OsRngMethod::Browser)) }
else if ty == 2 { Ok(OsRng(OsRngMethod::Node)) }
else { unreachable!() }
} else {
let err: WebError = js!{ return @{ result }.error }.try_into().unwrap();
Err(Error::with_cause(ErrorKind::Unavailable, "WASM Error", err))
}
}
fn fill_chunk(&mut self, dest: &mut [u8]) -> Result<(), Error> {
assert_eq!(mem::size_of::<usize>(), 4);
let len = dest.len() as u32;
let ptr = dest.as_mut_ptr() as i32;
let result = match self.0 {
OsRngMethod::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 };
}
},
OsRngMethod::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 {
Ok(())
} else {
let err: WebError = js!{ return @{ result }.error }.try_into().unwrap();
Err(Error::with_cause(ErrorKind::Unexpected, "WASM Error", err))
}
}
fn max_chunk_size(&self) -> usize { 65536 }
fn method_str(&self) -> &'static str {
match self.0 {
OsRngMethod::Browser => "Crypto.getRandomValues",
OsRngMethod::Node => "crypto.randomBytes",
}
}
}
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