rpc: Avoid copies in JSONRPCReplyObj()

Change parameters from const references to values, so they can be moved into
the reply instead of copied. Also update callers to move instead of copy.

src/bitcoin-cli.cpp

@@ -302,7 +302,7 @@ public:
         }
         addresses.pushKV("total", total);
         result.pushKV("addresses_known", addresses);
-        return JSONRPCReplyObj(result, NullUniValue, 1);
+        return JSONRPCReplyObj(std::move(result), NullUniValue, 1);
     }
 };
 
@@ -371,7 +371,7 @@ public:
         }
         result.pushKV("relayfee", batch[ID_NETWORKINFO]["result"]["relayfee"]);
         result.pushKV("warnings", batch[ID_NETWORKINFO]["result"]["warnings"]);
-        return JSONRPCReplyObj(result, NullUniValue, 1);
+        return JSONRPCReplyObj(std::move(result), NullUniValue, 1);
     }
 };
 
@@ -709,7 +709,7 @@ public:
         UniValue result(UniValue::VOBJ);
         result.pushKV("address", address_str);
         result.pushKV("blocks", reply.get_obj()["result"]);
-        return JSONRPCReplyObj(result, NullUniValue, 1);
+        return JSONRPCReplyObj(std::move(result), NullUniValue, 1);
     }
 protected:
     std::string address_str;

src/httprpc.cpp

@@ -73,7 +73,7 @@ static std::vector<std::vector<std::string>> g_rpcauth;
 static std::map<std::string, std::set<std::string>> g_rpc_whitelist;
 static bool g_rpc_whitelist_default = false;
 
-static void JSONErrorReply(HTTPRequest* req, const UniValue& objError, const UniValue& id)
+static void JSONErrorReply(HTTPRequest* req, UniValue objError, UniValue id)
 {
     // Send error reply from json-rpc error object
     int nStatus = HTTP_INTERNAL_SERVER_ERROR;
@@ -84,7 +84,7 @@ static void JSONErrorReply(HTTPRequest* req, const UniValue& objError, const Uni
     else if (code == RPC_METHOD_NOT_FOUND)
         nStatus = HTTP_NOT_FOUND;
 
-    std::string strReply = JSONRPCReply(NullUniValue, objError, id);
+    std::string strReply = JSONRPCReplyObj(NullUniValue, std::move(objError), std::move(id)).write() + "\n";
 
     req->WriteHeader("Content-Type", "application/json");
     req->WriteReply(nStatus, strReply);
@@ -203,7 +203,7 @@ static bool HTTPReq_JSONRPC(const std::any& context, HTTPRequest* req)
             UniValue result = tableRPC.execute(jreq);
 
             // Send reply
-            strReply = JSONRPCReply(result, NullUniValue, jreq.id);
+            strReply = JSONRPCReplyObj(std::move(result), NullUniValue, jreq.id).write() + "\n";
 
         // array of requests
         } else if (valRequest.isArray()) {
@@ -230,8 +230,8 @@ static bool HTTPReq_JSONRPC(const std::any& context, HTTPRequest* req)
 
         req->WriteHeader("Content-Type", "application/json");
         req->WriteReply(HTTP_OK, strReply);
-    } catch (const UniValue& objError) {
+    } catch (UniValue& e) {
-        JSONErrorReply(req, objError, jreq.id);
+        JSONErrorReply(req, std::move(e), jreq.id);
         return false;
     } catch (const std::exception& e) {
         JSONErrorReply(req, JSONRPCError(RPC_PARSE_ERROR, e.what()), jreq.id);

src/rpc/request.cpp

@@ -37,24 +37,18 @@ UniValue JSONRPCRequestObj(const std::string& strMethod, const UniValue& params,
     return request;
 }
 
-UniValue JSONRPCReplyObj(const UniValue& result, const UniValue& error, const UniValue& id)
+UniValue JSONRPCReplyObj(UniValue result, UniValue error, UniValue id)
 {
     UniValue reply(UniValue::VOBJ);
     if (!error.isNull())
         reply.pushKV("result", NullUniValue);
     else
-        reply.pushKV("result", result);
+        reply.pushKV("result", std::move(result));
-    reply.pushKV("error", error);
+    reply.pushKV("error", std::move(error));
-    reply.pushKV("id", id);
+    reply.pushKV("id", std::move(id));
     return reply;
 }
 
-std::string JSONRPCReply(const UniValue& result, const UniValue& error, const UniValue& id)
-{
-    UniValue reply = JSONRPCReplyObj(result, error, id);
-    return reply.write() + "\n";
-}
-
 UniValue JSONRPCError(int code, const std::string& message)
 {
     UniValue error(UniValue::VOBJ);

src/rpc/request.h

@@ -12,8 +12,7 @@
 #include <univalue.h>
 
 UniValue JSONRPCRequestObj(const std::string& strMethod, const UniValue& params, const UniValue& id);
-UniValue JSONRPCReplyObj(const UniValue& result, const UniValue& error, const UniValue& id);
+UniValue JSONRPCReplyObj(UniValue result, UniValue error, UniValue id);
-std::string JSONRPCReply(const UniValue& result, const UniValue& error, const UniValue& id);
 UniValue JSONRPCError(int code, const std::string& message);
 
 /** Generate a new RPC authentication cookie and write it to disk */

src/rpc/server.cpp

@@ -366,11 +366,11 @@ static UniValue JSONRPCExecOne(JSONRPCRequest jreq, const UniValue& req)
         jreq.parse(req);
 
         UniValue result = tableRPC.execute(jreq);
-        rpc_result = JSONRPCReplyObj(result, NullUniValue, jreq.id);
+        rpc_result = JSONRPCReplyObj(std::move(result), NullUniValue, jreq.id);
     }
-    catch (const UniValue& objError)
+    catch (UniValue& e)
     {
-        rpc_result = JSONRPCReplyObj(NullUniValue, objError, jreq.id);
+        rpc_result = JSONRPCReplyObj(NullUniValue, std::move(e), jreq.id);
     }
     catch (const std::exception& e)
     {