Use balances::TotalIssuance for scaling between votes and balances (#… (#2364)

* Use balances::TotalIssuance for scaling between votes and balances (#2361)

* Use total issuance to convert between votes and balances

* Remove cruft

* Bump runtime version

substrate/core/sr-primitives/src/traits.rs

@@ -150,35 +150,6 @@ impl<A, B: Default> Convert<A, B> for () {
 	fn convert(_: A) -> B { Default::default() }
 }
 
-/// A structure that converts the currency type into a lossy u64
-/// And back from u128
-pub struct CurrencyToVoteHandler;
-
-impl Convert<u128, u64> for CurrencyToVoteHandler {
-	fn convert(x: u128) -> u64 {
-		if x >> 96 == 0 {
-			// Remove dust; divide by 2^32
-			(x >> 32) as u64
-		} else {
-			u64::max_value()
-		}
-	}
-}
-
-impl Convert<u128, u128> for CurrencyToVoteHandler {
-	fn convert(x: u128) -> u128 {
-		// if it practically fits in u64
-		if x >> 64 == 0 {
-			// Add zero dust; multiply by 2^32
-			x << 32
-		}
-		else {
-			// 0000_0000_FFFF_FFFF_FFFF_FFFF_0000_0000
-			(u64::max_value() << 32) as u128
-		}
-	}
-}
-
 /// A structure that performs identity conversion.
 pub struct Identity;
 impl<T> Convert<T, T> for Identity {

substrate/node/runtime/src/lib.rs

@@ -34,8 +34,7 @@ use client::{
 use runtime_primitives::{ApplyResult, generic, create_runtime_str};
 use runtime_primitives::transaction_validity::TransactionValidity;
 use runtime_primitives::traits::{
-	BlakeTwo256, Block as BlockT, DigestFor, NumberFor, StaticLookup, CurrencyToVoteHandler,
-	AuthorityIdFor,
+	BlakeTwo256, Block as BlockT, DigestFor, NumberFor, StaticLookup, AuthorityIdFor, Convert
 };
 use version::RuntimeVersion;
 use council::{motions as council_motions, voting as council_voting};
@@ -59,8 +58,8 @@ pub const VERSION: RuntimeVersion = RuntimeVersion {
 	spec_name: create_runtime_str!("node"),
 	impl_name: create_runtime_str!("substrate-node"),
 	authoring_version: 10,
-	spec_version: 65,
-	impl_version: 65,
+	spec_version: 66,
+	impl_version: 66,
 	apis: RUNTIME_API_VERSIONS,
 };
 
@@ -73,6 +72,20 @@ pub fn native_version() -> NativeVersion {
 	}
 }
 
+pub struct CurrencyToVoteHandler;
+
+impl CurrencyToVoteHandler {
+	fn factor() -> u128 { (Balances::total_issuance() / u64::max_value() as u128).max(1) }
+}
+
+impl Convert<u128, u64> for CurrencyToVoteHandler {
+	fn convert(x: u128) -> u64 { (x / Self::factor()) as u64 }
+}
+
+impl Convert<u128, u128> for CurrencyToVoteHandler {
+	fn convert(x: u128) -> u128 { x * Self::factor() }
+}
+
 impl system::Trait for Runtime {
 	type Origin = Origin;
 	type Index = Index;