Implement 'blockchain.scripthash.listunspent' RPC

Following #475

contrib/history.py

@@ -67,11 +67,19 @@ def main():
         client.request('blockchain.scripthash.get_balance', script_hash)
         for script_hash in script_hashes
     )
-    for addr, balance in sorted(zip(args.address, balances), key=lambda v: v[0]):
-        if balance["confirmed"]:
-            log.info("{}: confirmed {:,.5f} mBTC", addr, balance["confirmed"] / 1e5)
-        if balance["unconfirmed"]:
-            log.info("{}: unconfirmed {:,.5f} mBTC", addr, balance["unconfirmed"] / 1e5)
+
+    unspents = conn.call(
+        client.request('blockchain.scripthash.listunspent', script_hash)
+        for script_hash in script_hashes
+    )
+    for addr, balance, unspent in sorted(zip(args.address, balances, unspents), key=lambda v: v[0]):
+        if unspent:
+            log.debug("{}: confirmed={:,.5f} mBTC, unconfirmed={:,.5f} mBTC",
+                addr, balance["confirmed"] / 1e5, balance["unconfirmed"] / 1e5)
+            for u in unspent:
+                log.debug("\t{}:{} = {:,.5f} mBTC {}",
+                    u["tx_hash"], u["tx_pos"], u["value"] / 1e5,
+                    f'@ {u["height"]}' if u["height"] else "")
 
     histories = conn.call(
         client.request('blockchain.scripthash.get_history', script_hash)

src/electrum.rs

@@ -256,6 +256,24 @@ impl Rpc {
         Ok(json!(history_entries))
     }
 
+    fn scripthash_list_unspent(
+        &self,
+        client: &Client,
+        (scripthash,): (ScriptHash,),
+    ) -> Result<Value> {
+        let unspent_entries = match client.scripthashes.get(&scripthash) {
+            Some(status) => self.tracker.get_unspent(status),
+            None => {
+                warn!(
+                    "blockchain.scripthash.listunspent called for unsubscribed scripthash: {}",
+                    scripthash
+                );
+                self.tracker.get_unspent(&self.new_status(scripthash)?)
+            }
+        };
+        Ok(json!(unspent_entries))
+    }
+
     fn scripthash_subscribe(
         &self,
         client: &mut Client,
@@ -406,6 +424,7 @@ impl Rpc {
                 Call::RelayFee => self.relayfee(),
                 Call::ScriptHashGetBalance(args) => self.scripthash_get_balance(client, args),
                 Call::ScriptHashGetHistory(args) => self.scripthash_get_history(client, args),
+                Call::ScriptHashListUnspent(args) => self.scripthash_list_unspent(client, args),
                 Call::ScriptHashSubscribe(args) => self.scripthash_subscribe(client, args),
                 Call::TransactionBroadcast(args) => self.transaction_broadcast(args),
                 Call::TransactionGet(args) => self.transaction_get(args),
@@ -445,6 +464,7 @@ enum Call {
     RelayFee,
     ScriptHashGetBalance((ScriptHash,)),
     ScriptHashGetHistory((ScriptHash,)),
+    ScriptHashListUnspent((ScriptHash,)),
     ScriptHashSubscribe((ScriptHash,)),
     TransactionGet(TxGetArgs),
     TransactionGetMerkle((Txid, usize)),
@@ -461,6 +481,7 @@ impl Call {
             "blockchain.relayfee" => Call::RelayFee,
             "blockchain.scripthash.get_balance" => Call::ScriptHashGetBalance(convert(params)?),
             "blockchain.scripthash.get_history" => Call::ScriptHashGetHistory(convert(params)?),
+            "blockchain.scripthash.listunspent" => Call::ScriptHashListUnspent(convert(params)?),
             "blockchain.scripthash.subscribe" => Call::ScriptHashSubscribe(convert(params)?),
             "blockchain.transaction.broadcast" => Call::TransactionBroadcast(convert(params)?),
             "blockchain.transaction.get" => Call::TransactionGet(convert(params)?),

src/status.rs

@@ -142,6 +142,17 @@ pub(crate) struct Balance {
     mempool_delta: SignedAmount,
 }
 
+// A single unspent transaction output entry:
+// https://electrumx-spesmilo.readthedocs.io/en/latest/protocol-methods.html#blockchain-scripthash-listunspent
+#[derive(Serialize)]
+pub(crate) struct UnspentEntry {
+    height: usize, // 0 = mempool entry
+    tx_hash: Txid,
+    tx_pos: u32,
+    #[serde(with = "bitcoin::util::amount::serde::as_sat")]
+    value: Amount,
+}
+
 #[derive(Default)]
 struct Unspent {
     // mapping an outpoint to its value & confirmation height
@@ -172,6 +183,18 @@ impl Unspent {
         unspent
     }
 
+    fn into_entries(self) -> Vec<UnspentEntry> {
+        self.outpoints
+            .into_iter()
+            .map(|(outpoint, (value, height))| UnspentEntry {
+                height,
+                tx_hash: outpoint.txid,
+                tx_pos: outpoint.vout,
+                value,
+            })
+            .collect()
+    }
+
     fn balance(&self) -> Amount {
         self.outpoints
             .values()
@@ -237,6 +260,10 @@ impl ScriptHashStatus {
             .collect()
     }
 
+    pub(crate) fn get_unspent(&self, chain: &Chain) -> Vec<UnspentEntry> {
+        Unspent::build(self, chain).into_entries()
+    }
+
     pub(crate) fn get_balance(&self, chain: &Chain) -> Balance {
         let unspent = Unspent::build(self, chain);
         Balance {

src/tracker.rs

@@ -12,7 +12,7 @@ use crate::{
     index::Index,
     mempool::{Histogram, Mempool},
     metrics::Metrics,
-    status::{Balance, HistoryEntry, ScriptHashStatus},
+    status::{Balance, HistoryEntry, ScriptHashStatus, UnspentEntry},
 };
 
 /// Electrum protocol subscriptions' tracker
@@ -55,6 +55,10 @@ impl Tracker {
         status.get_history(self.index.chain(), &self.mempool)
     }
 
+    pub(crate) fn get_unspent(&self, status: &ScriptHashStatus) -> Vec<UnspentEntry> {
+        status.get_unspent(self.index.chain())
+    }
+
     pub fn sync(&mut self, daemon: &Daemon) -> Result<()> {
         self.index.sync(daemon, self.index_batch_size)?;
         if !self.ignore_mempool {