wallet: add ExternalSignerScriptPubKeyMan

src/Makefile.am

@@ -266,6 +266,7 @@ BITCOIN_CORE_H = \
   wallet/db.h \
   wallet/dump.h \
   wallet/external_signer.h \
+  wallet/external_signer_scriptpubkeyman.h \
   wallet/feebumper.h \
   wallet/fees.h \
   wallet/ismine.h \
@@ -380,6 +381,7 @@ libbitcoin_wallet_a_SOURCES = \
   wallet/crypter.cpp \
   wallet/db.cpp \
   wallet/dump.cpp \
+  wallet/external_signer_scriptpubkeyman.cpp \
   wallet/external_signer.cpp \
   wallet/feebumper.cpp \
   wallet/fees.cpp \

src/wallet/external_signer_scriptpubkeyman.cpp

@@ -0,0 +1,36 @@
+// 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 <wallet/external_signer.h>
+#include <wallet/external_signer_scriptpubkeyman.h>
+
+#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;
+}
+
+#endif

src/wallet/external_signer_scriptpubkeyman.h

@@ -0,0 +1,28 @@
+// Copyright (c) 2019-2020 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_WALLET_EXTERNAL_SIGNER_SCRIPTPUBKEYMAN_H
+#define BITCOIN_WALLET_EXTERNAL_SIGNER_SCRIPTPUBKEYMAN_H
+
+#ifdef ENABLE_EXTERNAL_SIGNER
+#include <wallet/scriptpubkeyman.h>
+
+class ExternalSignerScriptPubKeyMan : public DescriptorScriptPubKeyMan
+{
+  public:
+  ExternalSignerScriptPubKeyMan(WalletStorage& storage, WalletDescriptor& descriptor)
+      :   DescriptorScriptPubKeyMan(storage, descriptor)
+      {}
+  ExternalSignerScriptPubKeyMan(WalletStorage& storage, bool internal)
+      :   DescriptorScriptPubKeyMan(storage, internal)
+      {}
+
+  /** Provide a descriptor at setup time
+  * Returns false if already setup or setup fails, true if setup is successful
+  */
+  bool SetupDescriptor(std::unique_ptr<Descriptor>desc);
+};
+#endif
+
+#endif // BITCOIN_WALLET_EXTERNAL_SIGNER_SCRIPTPUBKEYMAN_H

src/wallet/scriptpubkeyman.h

@@ -517,8 +517,6 @@ public:
 class DescriptorScriptPubKeyMan : public ScriptPubKeyMan
 {
 private:
-    WalletDescriptor m_wallet_descriptor GUARDED_BY(cs_desc_man);
-
     using ScriptPubKeyMap = std::map<CScript, int32_t>; // Map of scripts to descriptor range index
     using PubKeyMap = std::map<CPubKey, int32_t>; // Map of pubkeys involved in scripts to descriptor range index
     using CryptedKeyMap = std::map<CKeyID, std::pair<CPubKey, std::vector<unsigned char>>>;
@@ -547,6 +545,9 @@ private:
     // Fetch the SigningProvider for a given index and optionally include private keys. Called by the above functions.
     std::unique_ptr<FlatSigningProvider> GetSigningProvider(int32_t index, bool include_private = false) const EXCLUSIVE_LOCKS_REQUIRED(cs_desc_man);
 
+protected:
+  WalletDescriptor m_wallet_descriptor GUARDED_BY(cs_desc_man);
+
 public:
     DescriptorScriptPubKeyMan(WalletStorage& storage, WalletDescriptor& descriptor)
         :   ScriptPubKeyMan(storage),

src/wallet/wallet.cpp

@@ -32,6 +32,7 @@
 #include <util/translation.h>
 #include <wallet/coincontrol.h>
 #include <wallet/fees.h>
+#include <wallet/external_signer_scriptpubkeyman.h>
 
 #include <univalue.h>
 
@@ -4457,8 +4458,17 @@ void CWallet::ConnectScriptPubKeyManNotifiers()
 
 void CWallet::LoadDescriptorScriptPubKeyMan(uint256 id, WalletDescriptor& desc)
 {
-    auto spk_manager = std::unique_ptr<ScriptPubKeyMan>(new DescriptorScriptPubKeyMan(*this, desc));
+    if (IsWalletFlagSet(WALLET_FLAG_EXTERNAL_SIGNER)) {
-    m_spk_managers[id] = std::move(spk_manager);
+#ifdef ENABLE_EXTERNAL_SIGNER
+        auto spk_manager = std::unique_ptr<ScriptPubKeyMan>(new ExternalSignerScriptPubKeyMan(*this, desc));
+        m_spk_managers[id] = std::move(spk_manager);
+#else
+        throw std::runtime_error(std::string(__func__) + ": Configure with --enable-external-signer to use external signer wallets");
+#endif
+    } else {
+        auto spk_manager = std::unique_ptr<ScriptPubKeyMan>(new DescriptorScriptPubKeyMan(*this, desc));
+        m_spk_managers[id] = std::move(spk_manager);
+    }
 }
 
 void CWallet::SetupDescriptorScriptPubKeyMans()