wallet_rpc_server: new estimate_tx_size_and_weight RPC

src/wallet/wallet2.cpp

@@ -13601,4 +13601,22 @@ std::vector<cryptonote::public_node> wallet2::get_public_nodes(bool white_only)
   std::copy(res.gray.begin(), res.gray.end(), std::back_inserter(nodes));
   return nodes;
 }
+//----------------------------------------------------------------------------------------------------
+std::pair<size_t, uint64_t> wallet2::estimate_tx_size_and_weight(bool use_rct, int n_inputs, int ring_size, int n_outputs, size_t extra_size)
+{
+  THROW_WALLET_EXCEPTION_IF(n_inputs <= 0, tools::error::wallet_internal_error, "Invalid n_inputs");
+  THROW_WALLET_EXCEPTION_IF(n_outputs < 0, tools::error::wallet_internal_error, "Invalid n_outputs");
+  THROW_WALLET_EXCEPTION_IF(ring_size < 0, tools::error::wallet_internal_error, "Invalid ring size");
+
+  if (ring_size == 0)
+    ring_size = get_min_ring_size();
+  if (n_outputs == 1)
+    n_outputs = 2; // extra dummy output
+
+  const bool bulletproof = use_fork_rules(get_bulletproof_fork(), 0);
+  size_t size = estimate_tx_size(use_rct, n_inputs, ring_size - 1, n_outputs, extra_size, bulletproof);
+  uint64_t weight = estimate_tx_weight(use_rct, n_inputs, ring_size - 1, n_outputs, extra_size, bulletproof);
+  return std::make_pair(size, weight);
+}
+//----------------------------------------------------------------------------------------------------
 }

src/wallet/wallet2.h

@@ -1252,6 +1252,8 @@ private:
 
     bool is_unattended() const { return m_unattended; }
 
+    std::pair<size_t, uint64_t> estimate_tx_size_and_weight(bool use_rct, int n_inputs, int ring_size, int n_outputs, size_t extra_size);
+
     bool get_rpc_payment_info(bool mining, bool &payment_required, uint64_t &credits, uint64_t &diff, uint64_t &credits_per_hash_found, cryptonote::blobdata &hashing_blob, uint64_t &height, uint64_t &seed_height, crypto::hash &seed_hash, crypto::hash &next_seed_hash, uint32_t &cookie);
     bool daemon_requires_payment();
     bool make_rpc_payment(uint32_t nonce, uint32_t cookie, uint64_t &credits, uint64_t &balance);

src/wallet/wallet_rpc_server.cpp

@@ -4291,6 +4291,25 @@ namespace tools
     return true;
   }
   //------------------------------------------------------------------------------------------------------------------------------
+  bool wallet_rpc_server::on_estimate_tx_size_and_weight(const wallet_rpc::COMMAND_RPC_ESTIMATE_TX_SIZE_AND_WEIGHT::request& req, wallet_rpc::COMMAND_RPC_ESTIMATE_TX_SIZE_AND_WEIGHT::response& res, epee::json_rpc::error& er, const connection_context *ctx)
+  {
+    if (!m_wallet) return not_open(er);
+    try
+    {
+      size_t extra_size = 34 /* pubkey */ + 10 /* encrypted payment id */; // typical makeup
+      const std::pair<size_t, uint64_t> sw = m_wallet->estimate_tx_size_and_weight(req.rct, req.n_inputs, req.ring_size, req.n_outputs, extra_size);
+      res.size = sw.first;
+      res.weight = sw.second;
+    }
+    catch (const std::exception &e)
+    {
+      er.code = WALLET_RPC_ERROR_CODE_UNKNOWN_ERROR;
+      er.message = "Failed to determine size and weight";
+      return false;
+    }
+    return true;
+  }
+  //------------------------------------------------------------------------------------------------------------------------------
   bool wallet_rpc_server::on_get_version(const wallet_rpc::COMMAND_RPC_GET_VERSION::request& req, wallet_rpc::COMMAND_RPC_GET_VERSION::response& res, epee::json_rpc::error& er, const connection_context *ctx)
   {
     res.version = WALLET_RPC_VERSION;

src/wallet/wallet_rpc_server.h

@@ -154,6 +154,7 @@ namespace tools
         MAP_JON_RPC_WE("set_daemon",         on_set_daemon,         wallet_rpc::COMMAND_RPC_SET_DAEMON)
         MAP_JON_RPC_WE("set_log_level",      on_set_log_level,      wallet_rpc::COMMAND_RPC_SET_LOG_LEVEL)
         MAP_JON_RPC_WE("set_log_categories", on_set_log_categories, wallet_rpc::COMMAND_RPC_SET_LOG_CATEGORIES)
+        MAP_JON_RPC_WE("estimate_tx_size_and_weight", on_estimate_tx_size_and_weight, wallet_rpc::COMMAND_RPC_ESTIMATE_TX_SIZE_AND_WEIGHT)
         MAP_JON_RPC_WE("get_version",        on_get_version,        wallet_rpc::COMMAND_RPC_GET_VERSION)
       END_JSON_RPC_MAP()
     END_URI_MAP2()
@@ -240,6 +241,7 @@ namespace tools
       bool on_set_daemon(const wallet_rpc::COMMAND_RPC_SET_DAEMON::request& req, wallet_rpc::COMMAND_RPC_SET_DAEMON::response& res, epee::json_rpc::error& er, const connection_context *ctx = NULL);
       bool on_set_log_level(const wallet_rpc::COMMAND_RPC_SET_LOG_LEVEL::request& req, wallet_rpc::COMMAND_RPC_SET_LOG_LEVEL::response& res, epee::json_rpc::error& er, const connection_context *ctx = NULL);
       bool on_set_log_categories(const wallet_rpc::COMMAND_RPC_SET_LOG_CATEGORIES::request& req, wallet_rpc::COMMAND_RPC_SET_LOG_CATEGORIES::response& res, epee::json_rpc::error& er, const connection_context *ctx = NULL);
+      bool on_estimate_tx_size_and_weight(const wallet_rpc::COMMAND_RPC_ESTIMATE_TX_SIZE_AND_WEIGHT::request& req, wallet_rpc::COMMAND_RPC_ESTIMATE_TX_SIZE_AND_WEIGHT::response& res, epee::json_rpc::error& er, const connection_context *ctx = NULL);
       bool on_get_version(const wallet_rpc::COMMAND_RPC_GET_VERSION::request& req, wallet_rpc::COMMAND_RPC_GET_VERSION::response& res, epee::json_rpc::error& er, const connection_context *ctx = NULL);
 
       //json rpc v2

src/wallet/wallet_rpc_server_commands_defs.h

@@ -2580,5 +2580,36 @@ namespace wallet_rpc
     typedef epee::misc_utils::struct_init<response_t> response;
   };
 
+  struct COMMAND_RPC_ESTIMATE_TX_SIZE_AND_WEIGHT
+  {
+    struct request_t
+    {
+      uint32_t n_inputs;
+      uint32_t n_outputs;
+      uint32_t ring_size;
+      bool rct;
+
+      BEGIN_KV_SERIALIZE_MAP()
+        KV_SERIALIZE(n_inputs)
+        KV_SERIALIZE(n_outputs)
+        KV_SERIALIZE_OPT(ring_size, 0u)
+        KV_SERIALIZE_OPT(rct, true)
+      END_KV_SERIALIZE_MAP()
+    };
+    typedef epee::misc_utils::struct_init<request_t> request;
+
+    struct response_t
+    {
+      uint64_t size;
+      uint64_t weight;
+
+      BEGIN_KV_SERIALIZE_MAP()
+        KV_SERIALIZE(size)
+        KV_SERIALIZE(weight)
+      END_KV_SERIALIZE_MAP()
+    };
+    typedef epee::misc_utils::struct_init<response_t> response;
+  };
+
 }
 }

utils/python-rpc/framework/wallet.py

@@ -1062,6 +1062,20 @@ class Wallet(object):
         }
         return self.rpc.send_json_rpc_request(stop_mining)
 
+    def estimate_tx_size_and_weight(self, n_inputs, n_outputs, ring_size = 0, rct = True):
+        estimate_tx_size_and_weight = {
+            'method': 'estimate_tx_size_and_weight',
+            'jsonrpc': '2.0',
+            'params': {
+                'n_inputs': n_inputs,
+                'n_outputs': n_outputs,
+                'ring_size': ring_size,
+                'rct': rct,
+            },
+            'id': '0'
+        }
+        return self.rpc.send_json_rpc_request(estimate_tx_size_and_weight)
+
     def get_version(self):
         get_version = {
             'method': 'get_version',