sqlite: store if coin is from self

This adds a new `is_from_self` column to the coins table that
indicates if the coin is an output of a transaction for which
all inputs are ours. In the case of unconfirmed coins, being
from self requires that all unconfirmed ancestors, if any, are
also from self.

The DB migration sets the value of this column for all existing
coins and the poller keeps the column up to date.

lianad/src/bitcoin/poller/looper.rs

@@ -315,6 +315,9 @@ fn updates(
     db_conn.unspend_coins(&updated_coins.expired_spending);
     db_conn.spend_coins(&updated_coins.spending);
     db_conn.confirm_spend(&updated_coins.spent);
+    // Update info about which coins are from self only after
+    // coins have been inserted & updated above.
+    db_conn.update_coins_from_self(current_tip.height);
     if latest_tip != current_tip {
         db_conn.update_tip(&latest_tip);
         log::debug!("New tip: '{}'", latest_tip);

lianad/src/database/mod.rs

@@ -181,6 +181,10 @@ pub trait DatabaseConnection {
     /// Store transactions in database, ignoring any that already exist.
     fn new_txs(&mut self, txs: &[bitcoin::Transaction]);
 
+    /// For all unconfirmed coins and those confirmed after `current_tip_height`,
+    /// update whether the coin is from self or not.
+    fn update_coins_from_self(&mut self, current_tip_height: i32);
+
     /// Retrieve a list of transactions and their corresponding block heights and times.
     fn list_wallet_transactions(
         &mut self,
@@ -379,6 +383,11 @@ impl DatabaseConnection for SqliteConn {
         self.new_txs(txs)
     }
 
+    fn update_coins_from_self(&mut self, current_tip_height: i32) {
+        self.update_coins_from_self(current_tip_height)
+            .expect("must not fail")
+    }
+
     fn list_wallet_transactions(
         &mut self,
         txids: &[bitcoin::Txid],