Merge #14978: Factor out PSBT utilities from RPCs for use in GUI code; related refactoring.

102faad81 Factor out combine / finalize / extract PSBT helpers (Glenn Willen)
78b9893d0 Remove op== on PSBTs; check compatibility in Merge (Glenn Willen)
bd0dbe876 Switch away from exceptions in refactored tx code (Glenn Willen)
c6c3d42a7 Move PSBT definitions and code to separate files (Glenn Willen)
81cd95884 Factor BroadcastTransaction out of sendrawtransaction (Glenn Willen)
c734aaa15 Split DecodePSBT into Base64 and Raw versions (Glenn Willen)
162ffefd2 Add pf_invalid arg to std::string DecodeBase{32,64} (Glenn Willen)

Pull request description:

  * Move most PSBT definitions into psbt.h.
  * Move most PSBT RPC utilities into psbt.{h,cpp}.
  * Move wallet-touching PSBT RPC utilities (FillPSBT) into
      wallet/psbtwallet.{h,cpp}.
  * Switch exceptions from JSONRPCError() to new PSBTException class.
  * Split DecodePSBT into DecodeBase64PSBT (old behavior) and DecodeRawPSBT.
  * Add one new version of DecodeBase64 utility in strencodings.h (and
      corresponding DecodeBase32 for completeness).
  * Factor BroadcastTransaction utility function out of sendrawtransaction RPC
      handler in rpc/rawtransaction.cpp

  Note: For those keeping score at home wondering why refactor, this is in anticipation of (and developed in parallel with) a change to actually introduce GUI use of all this stuff, which is already under development and working-ish.

Tree-SHA512: 2197c448e657421f430943025357597e7b06c4c377d5d4b2622b9edea52a7193c48843dd731abb3a88ac4023a9c88d211991e0a9b740c22f2e1cbe72adefe390

3 files changed, 59 insertions, 93 deletions

diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
index c2f0c73851..7fe73e56da 100644
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -13,10 +13,11 @@
 #include <key_io.h>
 #include <keystore.h>
 #include <merkleblock.h>
-#include <net.h>
+#include <node/transaction.h>
 #include <policy/policy.h>
 #include <policy/rbf.h>
 #include <primitives/transaction.h>
+#include <psbt.h>
 #include <rpc/rawtransaction.h>
 #include <rpc/server.h>
 #include <rpc/util.h>
@@ -24,13 +25,11 @@
 #include <script/script_error.h>
 #include <script/sign.h>
 #include <script/standard.h>
-#include <txmempool.h>
 #include <uint256.h>
 #include <util/strencodings.h>
 #include <validation.h>
 #include <validationinterface.h>
 
-#include <future>
 #include <stdint.h>
 
 #include <univalue.h>
@@ -1041,8 +1040,6 @@ static UniValue sendrawtransaction(const JSONRPCRequest& request)
                 },
             }.ToString());
 
-    std::promise<void> promise;
-
     RPCTypeCheck(request.params, {UniValue::VSTR, UniValue::VBOOL});
 
     // parse hex string from parameter
@@ -1050,67 +1047,17 @@ static UniValue sendrawtransaction(const JSONRPCRequest& request)
     if (!DecodeHexTx(mtx, request.params[0].get_str()))
         throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "TX decode failed");
     CTransactionRef tx(MakeTransactionRef(std::move(mtx)));
-    const uint256& hashTx = tx->GetHash();
-
-    CAmount nMaxRawTxFee = maxTxFee;
-    if (!request.params[1].isNull() && request.params[1].get_bool())
-        nMaxRawTxFee = 0;
 
-    { // cs_main scope
-    LOCK(cs_main);
-    CCoinsViewCache &view = *pcoinsTip;
-    bool fHaveChain = false;
-    for (size_t o = 0; !fHaveChain && o < tx->vout.size(); o++) {
-        const Coin& existingCoin = view.AccessCoin(COutPoint(hashTx, o));
-        fHaveChain = !existingCoin.IsSpent();
+    bool allowhighfees = false;
+    if (!request.params[1].isNull()) allowhighfees = request.params[1].get_bool();
+    uint256 txid;
+    TransactionError err;
+    std::string err_string;
+    if (!BroadcastTransaction(tx, txid, err, err_string, allowhighfees)) {
+        throw JSONRPCTransactionError(err, err_string);
     }
-    bool fHaveMempool = mempool.exists(hashTx);
-    if (!fHaveMempool && !fHaveChain) {
-        // push to local node and sync with wallets
-        CValidationState state;
-        bool fMissingInputs;
-        if (!AcceptToMemoryPool(mempool, state, std::move(tx), &fMissingInputs,
-                                nullptr /* plTxnReplaced */, false /* bypass_limits */, nMaxRawTxFee)) {
-            if (state.IsInvalid()) {
-                throw JSONRPCError(RPC_TRANSACTION_REJECTED, FormatStateMessage(state));
-            } else {
-                if (fMissingInputs) {
-                    throw JSONRPCError(RPC_TRANSACTION_ERROR, "Missing inputs");
-                }
-                throw JSONRPCError(RPC_TRANSACTION_ERROR, FormatStateMessage(state));
-            }
-        } else {
-            // If wallet is enabled, ensure that the wallet has been made aware
-            // of the new transaction prior to returning. This prevents a race
-            // where a user might call sendrawtransaction with a transaction
-            // to/from their wallet, immediately call some wallet RPC, and get
-            // a stale result because callbacks have not yet been processed.
-            CallFunctionInValidationInterfaceQueue([&promise] {
-                promise.set_value();
-            });
-        }
-    } else if (fHaveChain) {
-        throw JSONRPCError(RPC_TRANSACTION_ALREADY_IN_CHAIN, "transaction already in block chain");
-    } else {
-        // Make sure we don't block forever if re-sending
-        // a transaction already in mempool.
-        promise.set_value();
-    }
-
-    } // cs_main
-
-    promise.get_future().wait();
-
-    if(!g_connman)
-        throw JSONRPCError(RPC_CLIENT_P2P_DISABLED, "Error: Peer-to-peer functionality missing or disabled");
 
-    CInv inv(MSG_TX, hashTx);
-    g_connman->ForEachNode([&inv](CNode* pnode)
-    {
-        pnode->PushInventory(inv);
-    });
-
-    return hashTx.GetHex();
+    return txid.GetHex();
 }
 
 static UniValue testmempoolaccept(const JSONRPCRequest& request)
@@ -1323,7 +1270,7 @@ UniValue decodepsbt(const JSONRPCRequest& request)
     // Unserialize the transactions
     PartiallySignedTransaction psbtx;
     std::string error;
-    if (!DecodePSBT(psbtx, request.params[0].get_str(), error)) {
+    if (!DecodeBase64PSBT(psbtx, request.params[0].get_str(), error)) {
         throw JSONRPCError(RPC_DESERIALIZATION_ERROR, strprintf("TX decode failed %s", error));
     }
 
@@ -1524,23 +1471,16 @@ UniValue combinepsbt(const JSONRPCRequest& request)
     for (unsigned int i = 0; i < txs.size(); ++i) {
         PartiallySignedTransaction psbtx;
         std::string error;
-        if (!DecodePSBT(psbtx, txs[i].get_str(), error)) {
+        if (!DecodeBase64PSBT(psbtx, txs[i].get_str(), error)) {
             throw JSONRPCError(RPC_DESERIALIZATION_ERROR, strprintf("TX decode failed %s", error));
         }
         psbtxs.push_back(psbtx);
     }
 
-    PartiallySignedTransaction merged_psbt(psbtxs[0]); // Copy the first one
-
-    // Merge
-    for (auto it = std::next(psbtxs.begin()); it != psbtxs.end(); ++it) {
-        if (*it != merged_psbt) {
-            throw JSONRPCError(RPC_INVALID_PARAMETER, "PSBTs do not refer to the same transactions.");
-        }
-        merged_psbt.Merge(*it);
-    }
-    if (!merged_psbt.IsSane()) {
-        throw JSONRPCError(RPC_INVALID_PARAMETER, "Merged PSBT is inconsistent");
+    PartiallySignedTransaction merged_psbt;
+    TransactionError error;
+    if (!CombinePSBTs(merged_psbt, error, psbtxs)) {
+        throw JSONRPCTransactionError(error);
     }
 
     UniValue result(UniValue::VOBJ);
@@ -1581,33 +1521,27 @@ UniValue finalizepsbt(const JSONRPCRequest& request)
     // Unserialize the transactions
     PartiallySignedTransaction psbtx;
     std::string error;
-    if (!DecodePSBT(psbtx, request.params[0].get_str(), error)) {
+    if (!DecodeBase64PSBT(psbtx, request.params[0].get_str(), error)) {
         throw JSONRPCError(RPC_DESERIALIZATION_ERROR, strprintf("TX decode failed %s", error));
     }
 
-    // Finalize input signatures -- in case we have partial signatures that add up to a complete
-    //   signature, but have not combined them yet (e.g. because the combiner that created this
-    //   PartiallySignedTransaction did not understand them), this will combine them into a final
-    //   script.
-    bool complete = true;
-    for (unsigned int i = 0; i < psbtx.tx->vin.size(); ++i) {
-        complete &= SignPSBTInput(DUMMY_SIGNING_PROVIDER, psbtx, i, SIGHASH_ALL);
-    }
+    bool extract = request.params[1].isNull() || (!request.params[1].isNull() && request.params[1].get_bool());
+
+    CMutableTransaction mtx;
+    bool complete = FinalizeAndExtractPSBT(psbtx, mtx);
 
     UniValue result(UniValue::VOBJ);
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
-    bool extract = request.params[1].isNull() || (!request.params[1].isNull() && request.params[1].get_bool());
+    std::string result_str;
+
     if (complete && extract) {
-        CMutableTransaction mtx(*psbtx.tx);
-        for (unsigned int i = 0; i < mtx.vin.size(); ++i) {
-            mtx.vin[i].scriptSig = psbtx.inputs[i].final_script_sig;
-            mtx.vin[i].scriptWitness = psbtx.inputs[i].final_script_witness;
-        }
         ssTx << mtx;
-        result.pushKV("hex", HexStr(ssTx.str()));
+        result_str = HexStr(ssTx.str());
+        result.pushKV("hex", result_str);
     } else {
         ssTx << psbtx;
-        result.pushKV("psbt", EncodeBase64(ssTx.str()));
+        result_str = EncodeBase64(ssTx.str());
+        result.pushKV("psbt", result_str);
     }
     result.pushKV("complete", complete);
 
diff --git a/src/rpc/util.cpp b/src/rpc/util.cpp
index ee7f3ca0dc..023b4b6746 100644
--- a/src/rpc/util.cpp
+++ b/src/rpc/util.cpp
@@ -141,6 +141,34 @@ unsigned int ParseConfirmTarget(const UniValue& value)
     return (unsigned int)target;
 }
 
+RPCErrorCode RPCErrorFromTransactionError(TransactionError terr)
+{
+    switch (terr) {
+        case TransactionError::MEMPOOL_REJECTED:
+            return RPC_TRANSACTION_REJECTED;
+        case TransactionError::ALREADY_IN_CHAIN:
+            return RPC_TRANSACTION_ALREADY_IN_CHAIN;
+        case TransactionError::P2P_DISABLED:
+            return RPC_CLIENT_P2P_DISABLED;
+        case TransactionError::INVALID_PSBT:
+        case TransactionError::PSBT_MISMATCH:
+            return RPC_INVALID_PARAMETER;
+        case TransactionError::SIGHASH_MISMATCH:
+            return RPC_DESERIALIZATION_ERROR;
+        default: break;
+    }
+    return RPC_TRANSACTION_ERROR;
+}
+
+UniValue JSONRPCTransactionError(TransactionError terr, const std::string& err_string)
+{
+    if (err_string.length() > 0) {
+        return JSONRPCError(RPCErrorFromTransactionError(terr), err_string);
+    } else {
+        return JSONRPCError(RPCErrorFromTransactionError(terr), TransactionErrorString(terr));
+    }
+}
+
 struct Section {
     Section(const std::string& left, const std::string& right)
         : m_left{left}, m_right{right} {}
diff --git a/src/rpc/util.h b/src/rpc/util.h
index d895e99c7e..1c9ddcdf44 100644
--- a/src/rpc/util.h
+++ b/src/rpc/util.h
@@ -5,6 +5,7 @@
 #ifndef BITCOIN_RPC_UTIL_H
 #define BITCOIN_RPC_UTIL_H
 
+#include <node/transaction.h>
 #include <pubkey.h>
 #include <script/standard.h>
 #include <univalue.h>
@@ -33,6 +34,9 @@ UniValue DescribeAddress(const CTxDestination& dest);
 //! Parse a confirm target option and raise an RPC error if it is invalid.
 unsigned int ParseConfirmTarget(const UniValue& value);
 
+RPCErrorCode RPCErrorFromTransactionError(TransactionError terr);
+UniValue JSONRPCTransactionError(TransactionError terr, const std::string& err_string = "");
+
 struct RPCArg {
     enum class Type {
         OBJ,