wallet: batch descriptor spkm TopUp

Instead of performing multiple atomic write
operations per descriptor setup call, batch
them all within a single atomic db txn.

Author: furszy

src/wallet/scriptpubkeyman.cpp

@@ -2135,6 +2135,15 @@ std::map<CKeyID, CKey> DescriptorScriptPubKeyMan::GetKeys() const
 }
 
 bool DescriptorScriptPubKeyMan::TopUp(unsigned int size)
+{
+    WalletBatch batch(m_storage.GetDatabase());
+    if (!batch.TxnBegin()) return false;
+    bool res = TopUpWithDB(batch, size);
+    if (!batch.TxnCommit()) throw std::runtime_error(strprintf("Error during descriptors keypool top up. Cannot commit changes for wallet %s", m_storage.GetDisplayName()));
+    return res;
+}
+
+bool DescriptorScriptPubKeyMan::TopUpWithDB(WalletBatch& batch, unsigned int size)
 {
     LOCK(cs_desc_man);
     unsigned int target_size;
@@ -2157,7 +2166,6 @@ bool DescriptorScriptPubKeyMan::TopUp(unsigned int size)
     FlatSigningProvider provider;
     provider.keys = GetKeys();
 
-    WalletBatch batch(m_storage.GetDatabase());
     uint256 id = GetID();
     for (int32_t i = m_max_cached_index + 1; i < new_range_end; ++i) {
         FlatSigningProvider out_keys;
@@ -2326,6 +2334,8 @@ bool DescriptorScriptPubKeyMan::SetupDescriptorGeneration(const CExtKey& master_
 
     // Store the master private key, and descriptor
     WalletBatch batch(m_storage.GetDatabase());
+    if (!batch.TxnBegin()) throw std::runtime_error(std::string(__func__) + ": cannot start db transaction");
+
     if (!AddDescriptorKeyWithDB(batch, master_key.key, master_key.key.GetPubKey())) {
         throw std::runtime_error(std::string(__func__) + ": writing descriptor master private key failed");
     }
@@ -2334,9 +2344,11 @@ bool DescriptorScriptPubKeyMan::SetupDescriptorGeneration(const CExtKey& master_
     }
 
     // TopUp
-    TopUp();
+    TopUpWithDB(batch);
 
     m_storage.UnsetBlankWalletFlag(batch);
+
+    if (!batch.TxnCommit()) throw std::runtime_error(std::string(__func__) + ": error committing db transaction");
     return true;
 }
 

src/wallet/scriptpubkeyman.h

@@ -583,7 +583,10 @@ class DescriptorScriptPubKeyMan : public ScriptPubKeyMan
     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);
+    WalletDescriptor m_wallet_descriptor GUARDED_BY(cs_desc_man);
+
+    //! Same as 'TopUp' but designed for use within a batch transaction context
+    bool TopUpWithDB(WalletBatch& batch, unsigned int size = 0);
 
 public:
     DescriptorScriptPubKeyMan(WalletStorage& storage, WalletDescriptor& descriptor, int64_t keypool_size)