wasm: Move JS-based Custom RNGs back into the main crate

They will be gated behind the "js" feature, as we can now do detect,
at compile-time, which implementation (wasm-bindgen vs stdweb) we
should use.

The "js" implementation takes precedence over the "custom"
implementation. This prevents issues that arise from the buggy way
Cargo handles features across multiple targets.

Signed-off-by: Joe Richey <joerichey@google.com>

Cargo.toml

@@ -14,12 +14,6 @@ exclude = ["utils/*", ".*", "appveyor.yml"]
 travis-ci = { repository = "rust-random/getrandom" }
 appveyor = { repository = "rust-random/getrandom" }
 
-[workspace]
-members = [
-    "custom/stdweb",
-    "custom/wasm-bindgen",
-]
-
 [dependencies]
 cfg-if = "0.1.2"
 
@@ -33,10 +27,19 @@ libc = { version = "0.2.64", default-features = false }
 [target.'cfg(target_os = "wasi")'.dependencies]
 wasi = "0.9"
 
+[target.'cfg(all(target_arch = "wasm32", target_os = "unknown", cargo_web))'.dependencies]
+stdweb = { version = "0.4.18", default-features = false, optional = true }
+[target.'cfg(all(target_arch = "wasm32", target_os = "unknown", not(cargo_web)))'.dependencies]
+wasm-bindgen = { version = "0.2.62", default-features = false, optional = true }
+[target.'cfg(all(target_arch = "wasm32", target_os = "unknown", not(cargo_web)))'.dev-dependencies]
+wasm-bindgen-test = "0.3.12"
+
 [features]
 std = []
 # Feature to enable fallback RDRAND-based implementation
 rdrand = []
+# Feature to enable JavaScript bindings on wasm32-unknown-unknown
+js = ["stdweb", "wasm-bindgen"]
 # Feature to enable custom RNG implementations
 custom = []
 # Unstable feature to support being a libstd dependency

src/lib.rs

@@ -186,6 +186,11 @@ cfg_if! {
     } else if #[cfg(all(feature = "rdrand",
                         any(target_arch = "x86_64", target_arch = "x86")))] {
         #[path = "rdrand.rs"] mod imp;
+    } else if #[cfg(all(feature = "js",
+                        target_arch = "wasm32", target_os = "unknown"))] {
+        #[cfg_attr(cargo_web, path = "stdweb.rs")]
+        #[cfg_attr(not(cargo_web), path = "wasm-bindgen.rs")]
+        mod imp;
     } else if #[cfg(feature = "custom")] {
         use custom as imp;
     } else {

custom/stdweb/src/lib.rs → src/stdweb.rs

@@ -5,17 +5,13 @@
 // <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.
+use crate::Error;
 
-#![recursion_limit = "128"]
-#[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
-compile_error!("This crate is only for the `wasm32-unknown-unknown` target");
-
+extern crate std;
 use std::thread_local;
 
 use stdweb::js;
 
-use getrandom::{register_custom_getrandom, Error};
-
 #[derive(Clone, Copy, PartialEq)]
 enum RngSource {
     Browser,
@@ -26,9 +22,7 @@ thread_local!(
     static RNG_SOURCE: Result<RngSource, Error> = getrandom_init();
 );
 
-register_custom_getrandom!(getrandom_inner);
-
-fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
+pub(crate) fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
     RNG_SOURCE.with(|&source| getrandom_fill(source?, dest))
 }
 

custom/wasm-bindgen/src/lib.rs → src/wasm-bindgen.rs

@@ -5,15 +5,13 @@
 // <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.
+use crate::Error;
 
-#[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
-compile_error!("This crate is only for the `wasm32-unknown-unknown` target");
-
+extern crate std;
 use std::thread_local;
 
 use wasm_bindgen::prelude::*;
 
-use getrandom::{register_custom_getrandom, Error};
 
 enum RngSource {
     Node(NodeCrypto),
@@ -26,9 +24,7 @@ thread_local!(
     static RNG_SOURCE: Result<RngSource, Error> = getrandom_init();
 );
 
-register_custom_getrandom!(getrandom_inner);
-
-fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
+pub(crate) fn getrandom_inner(dest: &mut [u8]) -> Result<(), Error> {
     RNG_SOURCE.with(|result| {
         let source = result.as_ref().map_err(|&e| e)?;