From f20380d6b46475cc4cc87ddb5cbe972b4c1aab9c Mon Sep 17 00:00:00 2001
From: Robert Kelly <robert.l.kelly3@gmail.com>
Date: Fri, 11 May 2018 14:07:41 -0400
Subject: [PATCH] changed RwLock to RefCell

---
 src/bin/genesis-demo.rs |  3 ++-
 src/signature.rs        | 13 +++++++------
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/bin/genesis-demo.rs b/src/bin/genesis-demo.rs
index 10ea4b9ef5..134d3403c6 100644
--- a/src/bin/genesis-demo.rs
+++ b/src/bin/genesis-demo.rs
@@ -42,13 +42,14 @@ fn main() {
 
     let users = rnd.gen_n_keys(num_accounts, tokens_per_user);
 
-    let last_id = demo.mint.last_id();
     let mint_keypair = demo.mint.keypair();
+    let last_id = demo.mint.last_id();
 
     eprintln!("Signing {} transactions...", num_accounts);
     let events: Vec<_> = users
         .into_par_iter()
         .map(|(pkcs8, tokens)| {
+            let last_id = demo.mint.last_id();
             let rando = KeyPair::from_pkcs8(Input::from(&pkcs8)).unwrap();
             let tr = Transaction::new(&mint_keypair, rando.pubkey(), tokens, last_id);
             Event::Transaction(tr)
diff --git a/src/signature.rs b/src/signature.rs
index f554fd0b8c..f882ca41c5 100644
--- a/src/signature.rs
+++ b/src/signature.rs
@@ -3,13 +3,12 @@
 use generic_array::typenum::{U32, U64};
 use generic_array::GenericArray;
 use rand::{ChaChaRng, Rng, SeedableRng};
-use rayon::prelude::*;
 use ring::error::Unspecified;
 use ring::rand::SecureRandom;
 use ring::signature::Ed25519KeyPair;
 use ring::{rand, signature};
+use std::cell::RefCell;
 use std::mem;
-use std::sync::RwLock;
 use untrusted;
 
 pub type KeyPair = Ed25519KeyPair;
@@ -49,7 +48,9 @@ impl SignatureUtil for GenericArray<u8, U64> {
 }
 
 pub struct GenKeys {
-    generator: RwLock<ChaChaRng>,
+    // This is necessary because the rng needs to mutate its state to remain
+    // deterministic, and the fill trait requires an immuatble reference to self
+    generator: RefCell<ChaChaRng>,
 }
 
 impl GenKeys {
@@ -57,7 +58,7 @@ impl GenKeys {
         let seed: &[u8] = &seed_values[..];
         let rng: ChaChaRng = SeedableRng::from_seed(unsafe { mem::transmute(seed) });
         GenKeys {
-            generator: RwLock::new(rng),
+            generator: RefCell::new(rng),
         }
     }
 
@@ -67,7 +68,7 @@ impl GenKeys {
 
     pub fn gen_n_keys(&self, n_keys: i64, tokens_per_user: i64) -> Vec<(Vec<u8>, i64)> {
         let users: Vec<_> = (0..n_keys)
-            .into_par_iter()
+            .into_iter()
             .map(|_| {
                 let pkcs8 = self.new_key();
                 (pkcs8, tokens_per_user)
@@ -79,7 +80,7 @@ impl GenKeys {
 
 impl SecureRandom for GenKeys {
     fn fill(&self, dest: &mut [u8]) -> Result<(), Unspecified> {
-        let mut rng = self.generator.write().unwrap();
+        let mut rng = self.generator.borrow_mut();
         rng.fill_bytes(dest);
         Ok(())
     }