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

5 files changed, 115 insertions, 59 deletions

diff --git a/src/wallet/psbtwallet.cpp b/src/wallet/psbtwallet.cpp
new file mode 100644
index 0000000000..761e7b7dd7
--- /dev/null
+++ b/src/wallet/psbtwallet.cpp
@@ -0,0 +1,62 @@
+// Copyright (c) 2009-2018 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <wallet/psbtwallet.h>
+
+bool FillPSBT(const CWallet* pwallet, PartiallySignedTransaction& psbtx, TransactionError& error, bool& complete, int sighash_type, bool sign, bool bip32derivs)
+{
+    LOCK(pwallet->cs_wallet);
+    // Get all of the previous transactions
+    complete = true;
+    for (unsigned int i = 0; i < psbtx.tx->vin.size(); ++i) {
+        const CTxIn& txin = psbtx.tx->vin[i];
+        PSBTInput& input = psbtx.inputs.at(i);
+
+        if (PSBTInputSigned(input)) {
+            continue;
+        }
+
+        // Verify input looks sane. This will check that we have at most one uxto, witness or non-witness.
+        if (!input.IsSane()) {
+            error = TransactionError::INVALID_PSBT;
+            return false;
+        }
+
+        // If we have no utxo, grab it from the wallet.
+        if (!input.non_witness_utxo && input.witness_utxo.IsNull()) {
+            const uint256& txhash = txin.prevout.hash;
+            const auto it = pwallet->mapWallet.find(txhash);
+            if (it != pwallet->mapWallet.end()) {
+                const CWalletTx& wtx = it->second;
+                // We only need the non_witness_utxo, which is a superset of the witness_utxo.
+                //   The signing code will switch to the smaller witness_utxo if this is ok.
+                input.non_witness_utxo = wtx.tx;
+            }
+        }
+
+        // Get the Sighash type
+        if (sign && input.sighash_type > 0 && input.sighash_type != sighash_type) {
+            error = TransactionError::SIGHASH_MISMATCH;
+            return false;
+        }
+
+        complete &= SignPSBTInput(HidingSigningProvider(pwallet, !sign, !bip32derivs), psbtx, i, sighash_type);
+    }
+
+    // Fill in the bip32 keypaths and redeemscripts for the outputs so that hardware wallets can identify change
+    for (unsigned int i = 0; i < psbtx.tx->vout.size(); ++i) {
+        const CTxOut& out = psbtx.tx->vout.at(i);
+        PSBTOutput& psbt_out = psbtx.outputs.at(i);
+
+        // Fill a SignatureData with output info
+        SignatureData sigdata;
+        psbt_out.FillSignatureData(sigdata);
+
+        MutableTransactionSignatureCreator creator(psbtx.tx.get_ptr(), 0, out.nValue, 1);
+        ProduceSignature(HidingSigningProvider(pwallet, true, !bip32derivs), creator, out.scriptPubKey, sigdata);
+        psbt_out.FromSignatureData(sigdata);
+    }
+
+    return true;
+}
diff --git a/src/wallet/psbtwallet.h b/src/wallet/psbtwallet.h
new file mode 100644
index 0000000000..b679f5c6ba
--- /dev/null
+++ b/src/wallet/psbtwallet.h
@@ -0,0 +1,36 @@
+// Copyright (c) 2009-2018 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_WALLET_PSBTWALLET_H
+#define BITCOIN_WALLET_PSBTWALLET_H
+
+#include <node/transaction.h>
+#include <psbt.h>
+#include <primitives/transaction.h>
+#include <wallet/wallet.h>
+
+/**
+ * Fills out a PSBT with information from the wallet. Fills in UTXOs if we have
+ * them. Tries to sign if sign=true. Sets `complete` if the PSBT is now complete
+ * (i.e. has all required signatures or signature-parts, and is ready to
+ * finalize.) Sets `error` and returns false if something goes wrong.
+ *
+ * @param[in]  pwallet pointer to a wallet
+ * @param[in]  &psbtx reference to PartiallySignedTransaction to fill in
+ * @param[out] &error reference to UniValue to fill with error info on failure
+ * @param[out] &complete indicates whether the PSBT is now complete
+ * @param[in]  sighash_type the sighash type to use when signing (if PSBT does not specify)
+ * @param[in]  sign whether to sign or not
+ * @param[in]  bip32derivs whether to fill in bip32 derivation information if available
+ * return true on success, false on error (and fills in `error`)
+ */
+bool FillPSBT(const CWallet* pwallet,
+              PartiallySignedTransaction& psbtx,
+              TransactionError& error,
+              bool& complete,
+              int sighash_type = 1 /* SIGHASH_ALL */,
+              bool sign = true,
+              bool bip32derivs = false);
+
+#endif // BITCOIN_WALLET_PSBTWALLET_H
diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index e836f50792..9e362cf167 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -13,6 +13,7 @@
 #include <validation.h>
 #include <key_io.h>
 #include <net.h>
+#include <node/transaction.h>
 #include <outputtype.h>
 #include <policy/feerate.h>
 #include <policy/fees.h>
@@ -30,6 +31,7 @@
 #include <util/moneystr.h>
 #include <wallet/coincontrol.h>
 #include <wallet/feebumper.h>
+#include <wallet/psbtwallet.h>
 #include <wallet/rpcwallet.h>
 #include <wallet/wallet.h>
 #include <wallet/walletdb.h>
@@ -3938,60 +3940,6 @@ void AddKeypathToMap(const CWallet* pwallet, const CKeyID& keyID, std::map<CPubK
     hd_keypaths.emplace(vchPubKey, std::move(info));
 }
 
-bool FillPSBT(const CWallet* pwallet, PartiallySignedTransaction& psbtx, int sighash_type, bool sign, bool bip32derivs)
-{
-    LOCK(pwallet->cs_wallet);
-    // Get all of the previous transactions
-    bool complete = true;
-    for (unsigned int i = 0; i < psbtx.tx->vin.size(); ++i) {
-        const CTxIn& txin = psbtx.tx->vin[i];
-        PSBTInput& input = psbtx.inputs.at(i);
-
-        if (PSBTInputSigned(input)) {
-            continue;
-        }
-
-        // Verify input looks sane. This will check that we have at most one uxto, witness or non-witness.
-        if (!input.IsSane()) {
-            throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "PSBT input is not sane.");
-        }
-
-        // If we have no utxo, grab it from the wallet.
-        if (!input.non_witness_utxo && input.witness_utxo.IsNull()) {
-            const uint256& txhash = txin.prevout.hash;
-            const auto it = pwallet->mapWallet.find(txhash);
-            if (it != pwallet->mapWallet.end()) {
-                const CWalletTx& wtx = it->second;
-                // We only need the non_witness_utxo, which is a superset of the witness_utxo.
-                //   The signing code will switch to the smaller witness_utxo if this is ok.
-                input.non_witness_utxo = wtx.tx;
-            }
-        }
-
-        // Get the Sighash type
-        if (sign && input.sighash_type > 0 && input.sighash_type != sighash_type) {
-            throw JSONRPCError(RPC_DESERIALIZATION_ERROR, "Specified Sighash and sighash in PSBT do not match.");
-        }
-
-        complete &= SignPSBTInput(HidingSigningProvider(pwallet, !sign, !bip32derivs), psbtx, i, sighash_type);
-    }
-
-    // Fill in the bip32 keypaths and redeemscripts for the outputs so that hardware wallets can identify change
-    for (unsigned int i = 0; i < psbtx.tx->vout.size(); ++i) {
-        const CTxOut& out = psbtx.tx->vout.at(i);
-        PSBTOutput& psbt_out = psbtx.outputs.at(i);
-
-        // Fill a SignatureData with output info
-        SignatureData sigdata;
-        psbt_out.FillSignatureData(sigdata);
-
-        MutableTransactionSignatureCreator creator(psbtx.tx.get_ptr(), 0, out.nValue, 1);
-        ProduceSignature(HidingSigningProvider(pwallet, true, !bip32derivs), creator, out.scriptPubKey, sigdata);
-        psbt_out.FromSignatureData(sigdata);
-    }
-    return complete;
-}
-
 UniValue walletprocesspsbt(const JSONRPCRequest& request)
 {
     std::shared_ptr<CWallet> const wallet = GetWalletForJSONRPCRequest(request);
@@ -4036,7 +3984,7 @@ UniValue walletprocesspsbt(const JSONRPCRequest& request)
     // Unserialize the transaction
     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));
     }
 
@@ -4046,7 +3994,11 @@ UniValue walletprocesspsbt(const JSONRPCRequest& request)
     // Fill transaction with our data and also sign
     bool sign = request.params[1].isNull() ? true : request.params[1].get_bool();
     bool bip32derivs = request.params[3].isNull() ? false : request.params[3].get_bool();
-    bool complete = FillPSBT(pwallet, psbtx, nHashType, sign, bip32derivs);
+    bool complete = true;
+    TransactionError err;
+    if (!FillPSBT(pwallet, psbtx, err, complete, nHashType, sign, bip32derivs)) {
+        throw JSONRPCTransactionError(err);
+    }
 
     UniValue result(UniValue::VOBJ);
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
@@ -4160,7 +4112,11 @@ UniValue walletcreatefundedpsbt(const JSONRPCRequest& request)
 
     // Fill transaction with out data but don't sign
     bool bip32derivs = request.params[4].isNull() ? false : request.params[4].get_bool();
-    FillPSBT(pwallet, psbtx, 1, false, bip32derivs);
+    bool complete = true;
+    TransactionError err;
+    if (!FillPSBT(pwallet, psbtx, err, complete, 1, false, bip32derivs)) {
+        throw JSONRPCTransactionError(err);
+    }
 
     // Serialize the PSBT
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);
diff --git a/src/wallet/rpcwallet.h b/src/wallet/rpcwallet.h
index abd7750874..58053bde59 100644
--- a/src/wallet/rpcwallet.h
+++ b/src/wallet/rpcwallet.h
@@ -30,5 +30,4 @@ bool EnsureWalletIsAvailable(CWallet *, bool avoidException);
 
 UniValue getaddressinfo(const JSONRPCRequest& request);
 UniValue signrawtransactionwithwallet(const JSONRPCRequest& request);
-bool FillPSBT(const CWallet* pwallet, PartiallySignedTransaction& psbtx, int sighash_type = 1 /* SIGHASH_ALL */, bool sign = true, bool bip32derivs = false);
 #endif //BITCOIN_WALLET_RPCWALLET_H
diff --git a/src/wallet/test/psbt_wallet_tests.cpp b/src/wallet/test/psbt_wallet_tests.cpp
index 9918eeb89f..e89d4121bc 100644
--- a/src/wallet/test/psbt_wallet_tests.cpp
+++ b/src/wallet/test/psbt_wallet_tests.cpp
@@ -5,6 +5,7 @@
 #include <key_io.h>
 #include <script/sign.h>
 #include <util/strencodings.h>
+#include <wallet/psbtwallet.h>
 #include <wallet/rpcwallet.h>
 #include <wallet/wallet.h>
 #include <univalue.h>
@@ -60,7 +61,9 @@ BOOST_AUTO_TEST_CASE(psbt_updater_test)
     ssData >> psbtx;
 
     // Fill transaction with our data
-    FillPSBT(&m_wallet, psbtx, SIGHASH_ALL, false, true);
+    TransactionError err;
+    bool complete = true;
+    FillPSBT(&m_wallet, psbtx, err, complete, SIGHASH_ALL, false, true);
 
     // Get the final tx
     CDataStream ssTx(SER_NETWORK, PROTOCOL_VERSION);