rpc: add external signer RPC files

src/wallet/interfaces.cpp

@@ -23,6 +23,7 @@
 #include <wallet/fees.h>
 #include <wallet/ismine.h>
 #include <wallet/load.h>
+#include <wallet/rpcsigner.h>
 #include <wallet/rpcwallet.h>
 #include <wallet/wallet.h>
 
@@ -518,6 +519,15 @@ public:
             }, command.argNames, command.unique_id);
             m_rpc_handlers.emplace_back(m_context.chain->handleRpc(m_rpc_commands.back()));
         }
+
+#ifdef ENABLE_EXTERNAL_SIGNER
+        for (const CRPCCommand& command : GetSignerRPCCommands()) {
+            m_rpc_commands.emplace_back(command.category, command.name, [this, &command](const JSONRPCRequest& request, UniValue& result, bool last_handler) {
+                return command.actor({request, m_context}, result, last_handler);
+            }, command.argNames, command.unique_id);
+            m_rpc_handlers.emplace_back(m_context.chain->handleRpc(m_rpc_commands.back()));
+        }
+#endif
     }
     bool verify() override { return VerifyWallets(*m_context.chain); }
     bool load() override { return LoadWallets(*m_context.chain); }

src/wallet/rpcsigner.cpp

@@ -0,0 +1,41 @@
+// Copyright (c) 2018-2021 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 <rpc/server.h>
+#include <util/strencodings.h>
+#include <wallet/rpcsigner.h>
+#include <wallet/wallet.h>
+
+#ifdef ENABLE_EXTERNAL_SIGNER
+
+// CRPCCommand table won't compile with an empty array
+static RPCHelpMan dummy()
+{
+    return RPCHelpMan{"dummy",
+                "\nDoes nothing.\n"
+                "",
+                {},
+                RPCResult{RPCResult::Type::NONE, "", ""},
+                RPCExamples{""},
+        [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
+{
+    return NullUniValue;
+},
+    };
+}
+
+Span<const CRPCCommand> GetSignerRPCCommands()
+{
+// clang-format off
+static const CRPCCommand commands[] =
+{ // category              actor (function)
+  // --------------------- ------------------------
+  { "signer",              &dummy,                },
+};
+// clang-format on
+    return MakeSpan(commands);
+}
+
+
+#endif // ENABLE_EXTERNAL_SIGNER

src/wallet/rpcsigner.h

@@ -0,0 +1,25 @@
+// Copyright (c) 2018-2021 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_RPCSIGNER_H
+#define BITCOIN_WALLET_RPCSIGNER_H
+
+#include <span.h>
+#include <util/system.h>
+#include <vector>
+
+#ifdef ENABLE_EXTERNAL_SIGNER
+
+class CRPCCommand;
+
+namespace interfaces {
+class Chain;
+class Handler;
+}
+
+Span<const CRPCCommand> GetSignerRPCCommands();
+
+#endif // ENABLE_EXTERNAL_SIGNER
+
+#endif //BITCOIN_WALLET_RPCSIGNER_H