wallet2: request transactions in slices when scanning for known rings

This avoid massive memory consumption for huge wallets

src/wallet/wallet2.cpp

@@ -5615,40 +5615,49 @@ bool wallet2::find_and_save_rings(bool force)
   MDEBUG("Finding and saving rings...");
 
   // get payments we made
+  std::vector<crypto::hash> txs_hashes;
   std::list<std::pair<crypto::hash,wallet2::confirmed_transfer_details>> payments;
   get_payments_out(payments, 0, std::numeric_limits<uint64_t>::max(), boost::none, std::set<uint32_t>());
   for (const std::pair<crypto::hash,wallet2::confirmed_transfer_details> &entry: payments)
   {
     const crypto::hash &txid = entry.first;
-    req.txs_hashes.push_back(epee::string_tools::pod_to_hex(txid));
+    txs_hashes.push_back(txid);
   }
 
-  MDEBUG("Found " << std::to_string(req.txs_hashes.size()) << " transactions");
-
-  // get those transactions from the daemon
-  req.decode_as_json = false;
-  req.prune = true;
-  bool r;
-  {
-    const boost::lock_guard<boost::mutex> lock{m_daemon_rpc_mutex};
-    r = epee::net_utils::invoke_http_json("/gettransactions", req, res, m_http_client, rpc_timeout);
-  }
-  THROW_WALLET_EXCEPTION_IF(!r, error::no_connection_to_daemon, "gettransactions");
-  THROW_WALLET_EXCEPTION_IF(res.status == CORE_RPC_STATUS_BUSY, error::daemon_busy, "gettransactions");
-  THROW_WALLET_EXCEPTION_IF(res.status != CORE_RPC_STATUS_OK, error::wallet_internal_error, "gettransactions");
-  THROW_WALLET_EXCEPTION_IF(res.txs.size() != req.txs_hashes.size(), error::wallet_internal_error,
-    "daemon returned wrong response for gettransactions, wrong txs count = " +
-    std::to_string(res.txs.size()) + ", expected " + std::to_string(req.txs_hashes.size()));
-
-  MDEBUG("Scanning " << res.txs.size() << " transactions");
+  MDEBUG("Found " << std::to_string(txs_hashes.size()) << " transactions");
 
   crypto::chacha_key key;
   generate_chacha_key_from_secret_keys(key);
 
-  auto it = req.txs_hashes.begin();
-  for (size_t i = 0; i < res.txs.size(); ++i, ++it)
+  // get those transactions from the daemon
+  static const size_t SLICE_SIZE = 200;
+  for (size_t slice = 0; slice < txs_hashes.size(); slice += SLICE_SIZE)
   {
+    req.decode_as_json = false;
+    req.prune = true;
+    req.txs_hashes.clear();
+    size_t ntxes = slice + SLICE_SIZE > txs_hashes.size() ? txs_hashes.size() - slice : SLICE_SIZE;
+    for (size_t s = slice; s < slice + ntxes; ++s)
+      req.txs_hashes.push_back(epee::string_tools::pod_to_hex(txs_hashes[s]));
+    bool r;
+    {
+      const boost::lock_guard<boost::mutex> lock{m_daemon_rpc_mutex};
+      r = epee::net_utils::invoke_http_json("/gettransactions", req, res, m_http_client, rpc_timeout);
+    }
+    THROW_WALLET_EXCEPTION_IF(!r, error::no_connection_to_daemon, "gettransactions");
+    THROW_WALLET_EXCEPTION_IF(res.status == CORE_RPC_STATUS_BUSY, error::daemon_busy, "gettransactions");
+    THROW_WALLET_EXCEPTION_IF(res.status != CORE_RPC_STATUS_OK, error::wallet_internal_error, "gettransactions");
+    THROW_WALLET_EXCEPTION_IF(res.txs.size() != req.txs_hashes.size(), error::wallet_internal_error,
+      "daemon returned wrong response for gettransactions, wrong txs count = " +
+      std::to_string(res.txs.size()) + ", expected " + std::to_string(req.txs_hashes.size()));
+
+    MDEBUG("Scanning " << res.txs.size() << " transactions");
+    THROW_WALLET_EXCEPTION_IF(slice + res.txs.size() > txs_hashes.size(), error::wallet_internal_error, "Unexpected tx array size");
+    auto it = req.txs_hashes.begin();
+    for (size_t i = 0; i < res.txs.size(); ++i, ++it)
+    {
     const auto &tx_info = res.txs[i];
+    THROW_WALLET_EXCEPTION_IF(tx_info.tx_hash != epee::string_tools::pod_to_hex(txs_hashes[slice + i]), error::wallet_internal_error, "Wrong txid received");
     THROW_WALLET_EXCEPTION_IF(tx_info.tx_hash != *it, error::wallet_internal_error, "Wrong txid received");
     cryptonote::blobdata bd;
     THROW_WALLET_EXCEPTION_IF(!epee::string_tools::parse_hexstr_to_binbuff(tx_info.as_hex, bd), error::wallet_internal_error, "failed to parse tx from hexstr");
@@ -5657,9 +5666,10 @@ bool wallet2::find_and_save_rings(bool force)
     THROW_WALLET_EXCEPTION_IF(!cryptonote::parse_and_validate_tx_from_blob(bd, tx, tx_hash, tx_prefix_hash), error::wallet_internal_error, "failed to parse tx from blob");
     THROW_WALLET_EXCEPTION_IF(epee::string_tools::pod_to_hex(tx_hash) != tx_info.tx_hash, error::wallet_internal_error, "txid mismatch");
     THROW_WALLET_EXCEPTION_IF(!add_rings(key, tx), error::wallet_internal_error, "Failed to save ring");
+    }
   }
 
-  MINFO("Found and saved rings for " << res.txs.size() << " transactions");
+  MINFO("Found and saved rings for " << txs_hashes.size() << " transactions");
   m_ring_history_saved = true;
   return true;
 }