wallet: Move listdescriptors retrieving from RPC to CWallet

When listdescriptors retrieves the descriptors from the wallet, instead
of having this logic in the RPC, move it into CWallet itself. This
will enable other functions to get the descriptors in an exportable
form.

Author: achow101

src/wallet/rpc/backup.cpp

@@ -503,40 +503,11 @@ RPCHelpMan listdescriptors()
     }
 
     LOCK(wallet->cs_wallet);
-
-    const auto active_spk_mans = wallet->GetActiveScriptPubKeyMans();
-
-    struct WalletDescInfo {
-        std::string descriptor;
-        uint64_t creation_time;
-        bool active;
-        std::optional<bool> internal;
-        std::optional<std::pair<int64_t,int64_t>> range;
-        int64_t next_index;
-    };
-
-    std::vector<WalletDescInfo> wallet_descriptors;
-    for (const auto& spk_man : wallet->GetAllScriptPubKeyMans()) {
-        const auto desc_spk_man = dynamic_cast<DescriptorScriptPubKeyMan*>(spk_man);
-        if (!desc_spk_man) {
-            throw JSONRPCError(RPC_WALLET_ERROR, "Unexpected ScriptPubKey manager type.");
-        }
-        LOCK(desc_spk_man->cs_desc_man);
-        const auto& wallet_descriptor = desc_spk_man->GetWalletDescriptor();
-        std::string descriptor;
-        if (!desc_spk_man->GetDescriptorString(descriptor, priv)) {
-            throw JSONRPCError(RPC_WALLET_ERROR, "Can't get descriptor string.");
-        }
-        const bool is_range = wallet_descriptor.descriptor->IsRange();
-        wallet_descriptors.push_back({
-            descriptor,
-            wallet_descriptor.creation_time,
-            active_spk_mans.count(desc_spk_man) != 0,
-            wallet->IsInternalScriptPubKeyMan(desc_spk_man),
-            is_range ? std::optional(std::make_pair(wallet_descriptor.range_start, wallet_descriptor.range_end)) : std::nullopt,
-            wallet_descriptor.next_index
-        });
+    util::Result<std::vector<WalletDescInfo>> exported = wallet->ExportDescriptors(priv);
+    if (!exported) {
+        throw JSONRPCError(RPC_WALLET_ERROR, util::ErrorString(exported).original);
     }
+    std::vector<WalletDescInfo> wallet_descriptors = *exported;
 
     std::sort(wallet_descriptors.begin(), wallet_descriptors.end(), [](const auto& a, const auto& b) {
         return a.descriptor < b.descriptor;

src/wallet/wallet.cpp

@@ -4482,4 +4482,32 @@ void CWallet::WriteBestBlock() const
         batch.WriteBestBlock(loc);
     }
 }
+
+util::Result<std::vector<WalletDescInfo>> CWallet::ExportDescriptors(bool export_private) const
+{
+    AssertLockHeld(cs_wallet);
+    std::vector<WalletDescInfo> wallet_descriptors;
+    for (const auto& spk_man : GetAllScriptPubKeyMans()) {
+        const auto desc_spk_man = dynamic_cast<DescriptorScriptPubKeyMan*>(spk_man);
+        if (!desc_spk_man) {
+            return util::Error{_("Unexpected ScriptPubKey manager type.")};
+        }
+        LOCK(desc_spk_man->cs_desc_man);
+        const auto& wallet_descriptor = desc_spk_man->GetWalletDescriptor();
+        std::string descriptor;
+        if (!desc_spk_man->GetDescriptorString(descriptor, export_private)) {
+            return util::Error{_("Can't get descriptor string.")};
+        }
+        const bool is_range = wallet_descriptor.descriptor->IsRange();
+        wallet_descriptors.push_back({
+            descriptor,
+            wallet_descriptor.creation_time,
+            IsActiveScriptPubKeyMan(*desc_spk_man),
+            IsInternalScriptPubKeyMan(desc_spk_man),
+            is_range ? std::optional(std::make_pair(wallet_descriptor.range_start, wallet_descriptor.range_end)) : std::nullopt,
+            wallet_descriptor.next_index
+        });
+    }
+    return wallet_descriptors;
+}
 } // namespace wallet

src/wallet/wallet.h

@@ -293,6 +293,18 @@ struct CRecipient
     bool fSubtractFeeFromAmount;
 };
 
+// Struct containing all of the info from WalletDescriptor, except with the descriptor as a string,
+// and without its ID or cache.
+// Used when exporting descriptors from the wallet.
+struct WalletDescInfo {
+    std::string descriptor;
+    uint64_t creation_time;
+    bool active;
+    std::optional<bool> internal;
+    std::optional<std::pair<int64_t,int64_t>> range;
+    int64_t next_index;
+};
+
 class WalletRescanReserver; //forward declarations for ScanForWalletTransactions/RescanFromTime
 /**
  * A CWallet maintains a set of transactions and balances, and provides the ability to create new transactions.
@@ -1053,6 +1065,9 @@ class CWallet final : public WalletStorage, public interfaces::Chain::Notificati
     //! Find the private key for the given key id from the wallet's descriptors, if available
     //! Returns nullopt when no descriptor has the key or if the wallet is locked.
     std::optional<CKey> GetKey(const CKeyID& keyid) const;
+
+    //! Export the descriptors from this wallet so that they can be imported elsewhere
+    util::Result<std::vector<WalletDescInfo>> ExportDescriptors(bool export_private) const EXCLUSIVE_LOCKS_REQUIRED(cs_wallet);
 };
 
 /**