wallet: add GetExternalSigner()

src/wallet/external_signer_scriptpubkeyman.cpp

@@ -33,4 +33,14 @@ bool ExternalSignerScriptPubKeyMan::SetupDescriptor(std::unique_ptr<Descriptor>
     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];
+}
+
 #endif

src/wallet/wallet.cpp

@@ -3573,6 +3573,19 @@ void ReserveDestination::ReturnDestination()
     address = CNoDestination();
 }
 
+#ifdef ENABLE_EXTERNAL_SIGNER
+ExternalSigner CWallet::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];
+}
+#endif
+
 void CWallet::LockCoin(const COutPoint& output)
 {
     AssertLockHeld(cs_wallet);

src/wallet/wallet.h

@@ -839,6 +839,9 @@ public:
 
     std::vector<OutputGroup> GroupOutputs(const std::vector<COutput>& outputs, bool separate_coins, const CFeeRate& effective_feerate, const CFeeRate& long_term_feerate, const CoinEligibilityFilter& filter, bool positive_only) const;
 
+#ifdef ENABLE_EXTERNAL_SIGNER
+    ExternalSigner GetExternalSigner() EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
+#endif
     bool IsLockedCoin(uint256 hash, unsigned int n) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     void LockCoin(const COutPoint& output) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
     void UnlockCoin(const COutPoint& output) EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);