Don't load spending txs of unspendable outputs

6 years ago · 7534bff544
2 changed files with 17 additions and 8 deletions
--- a/src/query.rs
+++ b/src/query.rs
@ -387,6 +387,18 @@ impl Query {
        })
    }

+    pub fn find_spending_for_funding_tx(&self, tx: Transaction) -> Result<Vec<Option<SpendingInput>>> {
+        let txid = tx.txid();
+        let mut spends = vec![];
+        for (output_index, output) in tx.output.iter().enumerate() {
+             let spend = if !output.is_fee() && !output.script_pubkey.is_provably_unspendable() {
+                 self.find_spending_by_outpoint((txid, output_index))?
+             } else { None };
+             spends.push(spend)
+         }
+        Ok(spends)
+    }
+
    // Internal API for transaction retrieval (uses bitcoind)
    fn _load_txn(&self, tx_hash: &Sha256dHash) -> Result<Transaction> {
        self.app.daemon().gettransaction(tx_hash)
--- a/src/rest.rs
+++ b/src/rest.rs
@ -456,14 +456,11 @@ fn handle_request(req: Request<Body>, query: &Arc<Query>, network: &Network) ->
        },
        (&Method::GET, Some(&"tx"), Some(hash), Some(&"outspends"), None) => {
            let hash = Sha256dHash::from_hex(hash)?;
-            // optimize: avoid fetching the entire tx just for the vout count
-            let out_count = query.tx_get(&hash).ok_or(StringError("cannot find tx".to_string()))?.output.len();
-            let mut spends = vec![];
-            for output_index in 0..out_count {
-                 let spend = query.find_spending_by_outpoint((hash, output_index))?
-                    .map_or_else(|| SpendingValue::default(), |spend| SpendingValue::from(spend));
-                 spends.push(spend)
-            }
+            let tx = query.tx_get(&hash).ok_or(StringError("cannot find tx".to_string()))?;
+            let spends: Vec<SpendingValue> = query.find_spending_for_funding_tx(tx)?
+                .into_iter()
+                .map(|spend| spend.map_or_else(|| SpendingValue::default(), |spend| SpendingValue::from(spend)))
+                .collect();
            json_response(spends)
        },
        _ => {