1 files changed, 107 insertions, 0 deletions
diff --git a/rand/rand_os/src/wasm32_stdweb.rs b/rand/rand_os/src/wasm32_stdweb.rs
new file mode 100644
index 0000000..3be0ce6
--- /dev/null
+++ b/rand/rand_os/src/wasm32_stdweb.rs
@@ -0,0 +1,107 @@
+// 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",
+        }
+    }
+}