[wallet] Change feebumper from class to functions

Change feebumper from a stateful class into a namespace of stateless
functions.

Having the results of feebumper calls persist in an object makes process
separation between Qt and wallet awkward, because it means the feebumper object
either has to be serialized back and forth between Qt and wallet processes
between fee bump calls, or that the feebumper object needs to stay alive in the
wallet process with an object reference passed back to Qt. It's simpler just to
have fee bumper calls return their results immediately instead of storing them
in an object with an extended lifetime.

In addition to making feebumper stateless, also:

- Move LOCK calls from Qt code to feebumper
- Move TransactionCanBeBumped implementation from Qt code to feebumper

1 files changed, 24 insertions, 19 deletions

diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 8738952bf1..2d2eb4b6d3 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -3125,45 +3125,50 @@ UniValue bumpfee(const JSONRPCRequest& request)
     LOCK2(cs_main, pwallet->cs_wallet);
     EnsureWalletIsUnlocked(pwallet);
 
-    feebumper::FeeBumper feeBump(pwallet, hash, coin_control, totalFee);
-    feebumper::Result res = feeBump.getResult();
-    if (res != feebumper::Result::OK)
-    {
+
+    std::vector<std::string> errors;
+    CAmount old_fee;
+    CAmount new_fee;
+    CMutableTransaction mtx;
+    feebumper::Result res = feebumper::CreateTransaction(pwallet, hash, coin_control, totalFee, errors, old_fee, new_fee, mtx);
+    if (res != feebumper::Result::OK) {
         switch(res) {
             case feebumper::Result::INVALID_ADDRESS_OR_KEY:
-                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, feeBump.getErrors()[0]);
+                throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, errors[0]);
                 break;
             case feebumper::Result::INVALID_REQUEST:
-                throw JSONRPCError(RPC_INVALID_REQUEST, feeBump.getErrors()[0]);
+                throw JSONRPCError(RPC_INVALID_REQUEST, errors[0]);
                 break;
             case feebumper::Result::INVALID_PARAMETER:
-                throw JSONRPCError(RPC_INVALID_PARAMETER, feeBump.getErrors()[0]);
+                throw JSONRPCError(RPC_INVALID_PARAMETER, errors[0]);
                 break;
             case feebumper::Result::WALLET_ERROR:
-                throw JSONRPCError(RPC_WALLET_ERROR, feeBump.getErrors()[0]);
+                throw JSONRPCError(RPC_WALLET_ERROR, errors[0]);
                 break;
             default:
-                throw JSONRPCError(RPC_MISC_ERROR, feeBump.getErrors()[0]);
+                throw JSONRPCError(RPC_MISC_ERROR, errors[0]);
                 break;
         }
     }
 
     // sign bumped transaction
-    if (!feeBump.signTransaction(pwallet)) {
+    if (!feebumper::SignTransaction(pwallet, mtx)) {
         throw JSONRPCError(RPC_WALLET_ERROR, "Can't sign transaction.");
     }
     // commit the bumped transaction
-    if(!feeBump.commit(pwallet)) {
-        throw JSONRPCError(RPC_WALLET_ERROR, feeBump.getErrors()[0]);
+    uint256 txid;
+    if (feebumper::CommitTransaction(pwallet, hash, std::move(mtx), errors, txid) != feebumper::Result::OK) {
+        throw JSONRPCError(RPC_WALLET_ERROR, errors[0]);
     }
     UniValue result(UniValue::VOBJ);
-    result.push_back(Pair("txid", feeBump.getBumpedTxId().GetHex()));
-    result.push_back(Pair("origfee", ValueFromAmount(feeBump.getOldFee())));
-    result.push_back(Pair("fee", ValueFromAmount(feeBump.getNewFee())));
-    UniValue errors(UniValue::VARR);
-    for (const std::string& err: feeBump.getErrors())
-        errors.push_back(err);
-    result.push_back(Pair("errors", errors));
+    result.push_back(Pair("txid", txid.GetHex()));
+    result.push_back(Pair("origfee", ValueFromAmount(old_fee)));
+    result.push_back(Pair("fee", ValueFromAmount(new_fee)));
+    UniValue result_errors(UniValue::VARR);
+    for (const std::string& error : errors) {
+        result_errors.push_back(error);
+    }
+    result.push_back(Pair("errors", result_errors));
 
     return result;
 }