Merge bitcoin#17584: wallet: replace raw pointer with const reference in AddrToPubKey

1a3a256 wallet: replace raw pointer with const reference in AddrToPubKey (Harris)

Pull request description:

  This PR replaces a redundant reference-to-pointer conversion in **addmultisigaddress** from *wallet/rpcwallet.cpp*. It also makes the API from *rpc/util.h* look more straightforward as **AddrToPubKey** now uses const references like other functions from there.

  I am not sure why there is a ref-to-ptr conversion in addmultisignatures, so I can only speculate that this is because of "historical reasons".

  The ref-to-ptr conversion happens here: https://github.com/bitcoin/bitcoin/blob/master/src/wallet/rpcwallet.cpp#L1001

  There, the address of LegacyScriptPubKeyMan& is given to AddrToPubKey.

  Later, in AddrToPubKey, it gets converted back to a reference, because GetKeyForDestination in rpc/util.cpp expects a const ref: https://github.com/bitcoin/bitcoin/blob/master/src/rpc/util.cpp#L140

  Regards,

ACKs for top commit:
  achow101:
    ACK 1a3a256
  meshcollider:
    utACK 1a3a256
  promag:
    Code review ACK 1a3a256.
  hebasto:
    ACK 1a3a256, I have not tested the code, but I have reviewed it and it looks OK, I agree it can be merged.

Tree-SHA512: 1a2b8ddab5694ef4c65fac69f011e38dd03a634e84a35857e13bd05ad99fe42af22ee0af6230865e3d2c725693512f3336acb055ede19c958424283e7a3856c4

Author: meshcollider

src/rpc/util.cpp

@@ -131,18 +131,18 @@ CPubKey HexToPubKey(const std::string& hex_in)
 }
 
 // Retrieves a public key for an address from the given FillableSigningProvider
-CPubKey AddrToPubKey(FillableSigningProvider* const keystore, const std::string& addr_in)
+CPubKey AddrToPubKey(const FillableSigningProvider& keystore, const std::string& addr_in)
 {
     CTxDestination dest = DecodeDestination(addr_in);
     if (!IsValidDestination(dest)) {
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Invalid address: " + addr_in);
     }
-    CKeyID key = GetKeyForDestination(*keystore, dest);
+    CKeyID key = GetKeyForDestination(keystore, dest);
     if (key.IsNull()) {
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, strprintf("%s does not refer to a key", addr_in));
     }
     CPubKey vchPubKey;
-    if (!keystore->GetPubKey(key, vchPubKey)) {
+    if (!keystore.GetPubKey(key, vchPubKey)) {
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, strprintf("no full public key for address %s", addr_in));
     }
     if (!vchPubKey.IsFullyValid()) {

src/rpc/util.h

@@ -69,7 +69,7 @@ extern std::string HelpExampleCli(const std::string& methodname, const std::stri
 extern std::string HelpExampleRpc(const std::string& methodname, const std::string& args);
 
 CPubKey HexToPubKey(const std::string& hex_in);
-CPubKey AddrToPubKey(FillableSigningProvider* const keystore, const std::string& addr_in);
+CPubKey AddrToPubKey(const FillableSigningProvider& keystore, const std::string& addr_in);
 CTxDestination AddAndGetMultisigDestination(const int required, const std::vector<CPubKey>& pubkeys, OutputType type, FillableSigningProvider& keystore, CScript& script_out);
 
 UniValue DescribeAddress(const CTxDestination& dest);

src/wallet/rpcwallet.cpp

@@ -998,7 +998,7 @@ static UniValue addmultisigaddress(const JSONRPCRequest& request)
         if (IsHex(keys_or_addrs[i].get_str()) && (keys_or_addrs[i].get_str().length() == 66 || keys_or_addrs[i].get_str().length() == 130)) {
             pubkeys.push_back(HexToPubKey(keys_or_addrs[i].get_str()));
         } else {
-            pubkeys.push_back(AddrToPubKey(&spk_man, keys_or_addrs[i].get_str()));
+            pubkeys.push_back(AddrToPubKey(spk_man, keys_or_addrs[i].get_str()));
         }
     }