1 files changed, 88 insertions, 0 deletions
diff --git a/src/wallet/external_signer_scriptpubkeyman.cpp b/src/wallet/external_signer_scriptpubkeyman.cpp
new file mode 100644
index 0000000000..fe2c810afa
--- /dev/null
+++ b/src/wallet/external_signer_scriptpubkeyman.cpp
@@ -0,0 +1,88 @@
+// Copyright (c) 2020 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 <chainparams.h>
+#include <external_signer.h>
+#include <wallet/external_signer_scriptpubkeyman.h>
+
+#include <iostream>
+#include <memory>
+#include <stdexcept>
+#include <string>
+#include <utility>
+#include <vector>
+
+#ifdef ENABLE_EXTERNAL_SIGNER
+
+bool ExternalSignerScriptPubKeyMan::SetupDescriptor(std::unique_ptr<Descriptor> desc)
+{
+    LOCK(cs_desc_man);
+    assert(m_storage.IsWalletFlagSet(WALLET_FLAG_DESCRIPTORS));
+    assert(m_storage.IsWalletFlagSet(WALLET_FLAG_EXTERNAL_SIGNER));
+
+    int64_t creation_time = GetTime();
+
+    // Make the descriptor
+    WalletDescriptor w_desc(std::move(desc), creation_time, 0, 0, 0);
+    m_wallet_descriptor = w_desc;
+
+    // Store the descriptor
+    WalletBatch batch(m_storage.GetDatabase());
+    if (!batch.WriteDescriptor(GetID(), m_wallet_descriptor)) {
+        throw std::runtime_error(std::string(__func__) + ": writing descriptor failed");
+    }
+
+    // TopUp
+    TopUp();
+
+    m_storage.UnsetBlankWalletFlag(batch);
+    return true;
+}
+
+ExternalSigner ExternalSignerScriptPubKeyMan::GetExternalSigner() {
+    const std::string command = gArgs.GetArg("-signer", "");
+    if (command == "") throw std::runtime_error(std::string(__func__) + ": restart bitcoind with -signer=<cmd>");
+    std::vector<ExternalSigner> signers;
+    ExternalSigner::Enumerate(command, signers, Params().NetworkIDString());
+    if (signers.empty()) throw std::runtime_error(std::string(__func__) + ": No external signers found");
+    // TODO: add fingerprint argument in case of multiple signers
+    return signers[0];
+}
+
+bool ExternalSignerScriptPubKeyMan::DisplayAddress(const CScript scriptPubKey, const ExternalSigner &signer) const
+{
+    // TODO: avoid the need to infer a descriptor from inside a descriptor wallet
+    auto provider = GetSolvingProvider(scriptPubKey);
+    auto descriptor = InferDescriptor(scriptPubKey, *provider);
+
+    signer.DisplayAddress(descriptor->ToString());
+    // TODO inspect result
+    return true;
+}
+
+// If sign is true, transaction must previously have been filled
+TransactionError ExternalSignerScriptPubKeyMan::FillPSBT(PartiallySignedTransaction& psbt, int sighash_type, bool sign, bool bip32derivs, int* n_signed) const
+{
+    if (!sign) {
+        return DescriptorScriptPubKeyMan::FillPSBT(psbt, sighash_type, false, bip32derivs, n_signed);
+    }
+
+    // Already complete if every input is now signed
+    bool complete = true;
+    for (const auto& input : psbt.inputs) {
+        // TODO: for multisig wallets, we should only care if all _our_ inputs are signed
+        complete &= PSBTInputSigned(input);
+    }
+    if (complete) return TransactionError::OK;
+
+    std::string strFailReason;
+    if(!GetExternalSigner().SignTransaction(psbt, strFailReason)) {
+        tfm::format(std::cerr, "Failed to sign: %s\n", strFailReason);
+        return TransactionError::EXTERNAL_SIGNER_FAILED;
+    }
+    FinalizePSBT(psbt); // This won't work in a multisig setup
+    return TransactionError::OK;
+}
+
+#endif