Update roadmap and comments

TODO.md

@@ -1,7 +1,8 @@
-* [ ] Add caching layer: This cache layer can built on top of the utxo::ledger,
-  because all operations can be safely cached until a new transaction
-  referencing their account is issued, by that point, all the caches related to
-  anaccount can be evicted
-* [ ] Build admin interface
-* [ ] ADd memo to changes. Build append only table with all movements as
-  inserts. Wraps the objects to all their changes
+- [ ] Add a locking mechanism, to either a start a tx per account, or use the storage engine as a lock mechanism (to lock the utxos)
+- [ ] Optimize `select_inputs_from_accounts` to return a single change operation instead of a vector
+- [ ] Add ability to query accounts in a point in time
+- [ ] Write other servers, other than the restful server
+- [ ] Add caching layer: This cache layer can built on top of the utxo::ledger, because all operations can be safely cached until a new transaction referencing their account is issued, by that point, all the caches related to anaccount can be evicted
+- [ ] Build admin interface
+- [ ] Add memo to changes. Build append only table with all movements as
+      inserts. Wraps the objects to all their changes

utxo/src/ledger.rs

@@ -41,15 +41,17 @@ where
         &self.asset_manager
     }
 
-    /// Selects the unspent payments to be used as inputs of the new transaction.
+    /// Selects all inputs to be used in a transaction. The inputs are selected
+    /// from each account in a ascendent order.
     ///
-    /// This function also returns a list of transactions that will be used as
-    /// exchanged transactions, to make sure the main transaction doesn't hold
-    /// extra funds, by splitting any large unspent payments into two, one that
-    /// matches exactly the needed amount, and another one that will be used as
-    /// change. These exchange transaction are internal transactions and they
-    /// are created as settled.
-    async fn create_inputs_to_pay_from_accounts(
+    /// The returned inputs to be used matched exactly with the amounts to be
+    /// spent. Optionally a vector of transactions to be executed before are
+    /// returned. These transactions are `exchange` transactions, and settle
+    /// immediately, because they are internal transactions needed to be sure the
+    /// inputs to be used as input matches exactly the amounts to be spent, to
+    /// avoid locking any exchange amount to the duration of the transaction
+    /// (which is unknown)
+    async fn select_inputs_from_accounts(
         &self,
         payments: Vec<(AccountId, Amount)>,
     ) -> Result<(Vec<Transaction>, Vec<Payment>), Error> {
@@ -167,7 +169,7 @@ where
         from: Vec<(AccountId, Amount)>,
         to: Vec<(AccountId, Amount)>,
     ) -> Result<Transaction, Error> {
-        let (change_transactions, payments) = self.create_inputs_to_pay_from_accounts(from).await?;
+        let (change_transactions, payments) = self.select_inputs_from_accounts(from).await?;
 
         for mut change_tx in change_transactions.into_iter() {
             change_tx.persist(&self.storage).await?;
@@ -222,7 +224,7 @@ where
         reference: String,
     ) -> Result<Transaction, Error> {
         let (change_transactions, payments) = self
-            .create_inputs_to_pay_from_accounts(vec![(account.clone(), amount)])
+            .select_inputs_from_accounts(vec![(account.clone(), amount)])
             .await?;
         for mut change_tx in change_transactions.into_iter() {
             change_tx.persist(&self.storage).await?;