[feature] show indexed coin value (#171)

Co-authored-by: 0o-de-lally <[email protected]>

framework/libra-framework/sources/modified_source/coin.move

@@ -13,6 +13,7 @@ module diem_framework::coin {
     use diem_framework::system_addresses;
 
     use diem_std::type_info;
+    use diem_std::math128;
     // use diem_std::debug::print;
 
     friend ol_framework::libra_coin;
@@ -563,6 +564,16 @@ module diem_framework::coin {
         coin.value
     }
 
+    /// Returns an indexed value based on the current supply, compared to the
+    /// final supply
+    public fun index_value<CoinType>(coin: &Coin<CoinType>, index_supply: u128):
+    u128 acquires CoinInfo {
+        let units = (value(coin) as u128);
+        let supply_now_opt = supply<CoinType>();
+        let supply_now = option::borrow(&supply_now_opt);
+        math128::mul_div(units, *supply_now, index_supply)
+    }
+
     /// Withdraw specifed `amount` of coin `CoinType` from the signing account.
     public(friend) fun withdraw<CoinType>(
         account: &signer,

framework/libra-framework/sources/ol_sources/libra_coin.move

@@ -334,7 +334,6 @@ module ol_framework::libra_coin {
         coin::destroy_freeze_cap(freeze_cap);
         (burn_cap, mint_cap)
     }
-
     // This is particularly useful if the aggregator_factory is already initialized via another call path.
     #[test_only]
     public fun initialize_for_test_without_aggregator_factory(diem_framework: &signer): (BurnCapability<LibraCoin>, MintCapability<LibraCoin>) {

framework/libra-framework/sources/ol_sources/ol_account.move

@@ -54,10 +54,6 @@ module ol_framework::ol_account {
     /// why is VM trying to use this?
     const ENOT_FOR_VM: u64 = 9;
 
-
-
-
-
     struct BurnTracker has key {
       prev_supply: u64,
       prev_balance: u64,
@@ -334,6 +330,29 @@ module ol_framework::ol_account {
       slow_wallet::balance(addr)
     }
 
+    #[view]
+    /// returns the INDEXED value of the coins.
+    // Note: there is a similar function in coin.move to get the indexed
+    // value of a single coin.
+    public fun real_balance(addr: address): (u64, u64) {
+      let final = libra_coin::get_final_supply();
+      let current = libra_coin::supply();
+      let (unlocked, total) = slow_wallet::balance(addr);
+
+      let unlocked_indexed = math64::mul_div(unlocked, final, current);
+      let total_indexed = math64::mul_div(total, final, current);
+
+      (unlocked_indexed, total_indexed)
+      // Going to another place
+      // Another universe, another realm
+      // Sleeping, dreaming, what is real?
+      // Leap and the net will appear
+      // Going to another place
+      // Another universe, another realm
+      // Sleeping, dreaming, what is real?
+      // Leap and the net will appear
+    }
+
     #[view]
     /// Returns a human readable version of the balance with (integer, decimal_part)
     public fun balance_human(owner: address): (u64, u64) {

framework/libra-framework/sources/ol_sources/tests/burn.test.move

@@ -19,7 +19,6 @@ module ol_framework::test_burn {
   // use diem_std::debug::print;
 
   #[test(root = @ol_framework, alice = @0x1000a)]
-
   fun burn_reduces_supply(root: &signer, alice: &signer) {
     mock::genesis_n_vals(root, 1);
     mock::ol_initialize_coin_and_fund_vals(root, 10000, true);
@@ -30,9 +29,41 @@ module ol_framework::test_burn {
     burn::burn_and_track(c);
     let supply = libra_coin::supply();
     assert!(supply == (supply_pre - alice_burn), 7357001);
-
   }
 
+  // burn changes indexed real_balance
+  #[test(root = @ol_framework, alice = @0x1000a)]
+  fun burn_changes_real_balance(root: &signer, alice: &signer) {
+    mock::genesis_n_vals(root, 1);
+    // the mint to alice will double the supply
+    mock::ol_initialize_coin_and_fund_vals(root, 100000000, true);
+
+    let supply_pre = libra_coin::supply();
+    // need to adjust this since the validator init increased the supply above
+    // the final
+    libra_coin::test_set_final_supply(root, supply_pre);
+    let final = libra_coin::get_final_supply();
+    assert!(supply_pre == final, 7357000);
+    // no change should happen before any burns
+    let (unlocked, total) = ol_account::balance(@0x1000a);
+    let (real_unlocked, real_total) = ol_account::real_balance(@0x1000a);
+    assert!(real_unlocked == unlocked, 7357001);
+    assert!(real_total == total, 7357002);
+
+    // burn half of alices coins, which is 25% of the supply
+    let alice_burn = 50000000;
+
+
+    let c = ol_account::withdraw(alice, alice_burn);
+    burn::burn_and_track(c);
+    let supply = libra_coin::supply();
+    assert!(supply == (supply_pre - alice_burn), 7357003);
+
+    let (unlocked, total) = ol_account::balance(@0x1000a);
+    let (real_unlocked, real_total) = ol_account::real_balance(@0x1000a);
+    assert!(real_unlocked > unlocked, 7357004);
+    assert!(real_total > total, 7357005);
+  }
 
 
     #[test(root = @ol_framework, alice = @0x1000a, bob = @0x1000d, eve = @0x1000e)]