[sync] Improve sync

Make every request in batch, to save round trip times
Fetch timestamp of blockheader to populate timestamp field in transaction
Remove listunspent requests because we can compute it from our history

src/blockchain/electrum.rs

@@ -42,11 +42,11 @@ use std::collections::HashSet;
 #[allow(unused_imports)]
 use log::{debug, error, info, trace};
 
-use bitcoin::{Script, Transaction, Txid};
+use bitcoin::{BlockHeader, Script, Transaction, Txid};
 
 use electrum_client::{Client, ElectrumApi};
 
-use self::utils::{ELSGetHistoryRes, ELSListUnspentRes, ElectrumLikeSync};
+use self::utils::{ELSGetHistoryRes, ElectrumLikeSync};
 use super::*;
 use crate::database::BatchDatabase;
 use crate::error::Error;
@@ -141,36 +141,18 @@ impl ElectrumLikeSync for Client {
             .map_err(Error::Electrum)
     }
 
-    fn els_batch_script_list_unspent<'s, I: IntoIterator<Item = &'s Script>>(
+    fn els_batch_transaction_get<'s, I: IntoIterator<Item = &'s Txid>>(
         &self,
-        scripts: I,
-    ) -> Result<Vec<Vec<ELSListUnspentRes>>, Error> {
-        self.batch_script_list_unspent(scripts)
-            .map(|v| {
-                v.into_iter()
-                    .map(|v| {
-                        v.into_iter()
-                            .map(
-                                |electrum_client::ListUnspentRes {
-                                     height,
-                                     tx_hash,
-                                     tx_pos,
-                                     ..
-                                 }| ELSListUnspentRes {
-                                    height,
-                                    tx_hash,
-                                    tx_pos,
-                                },
-                            )
-                            .collect()
-                    })
-                    .collect()
-            })
-            .map_err(Error::Electrum)
+        txids: I,
+    ) -> Result<Vec<Transaction>, Error> {
+        self.batch_transaction_get(txids).map_err(Error::Electrum)
     }
 
-    fn els_transaction_get(&self, txid: &Txid) -> Result<Transaction, Error> {
-        self.transaction_get(txid).map_err(Error::Electrum)
+    fn els_batch_block_header<I: IntoIterator<Item = u32>>(
+        &self,
+        heights: I,
+    ) -> Result<Vec<BlockHeader>, Error> {
+        self.batch_block_header(heights).map_err(Error::Electrum)
     }
 }