wallet, descspkm: Refactor wallet descriptor generation to standalone func

src/wallet/scriptpubkeyman.cpp

@@ -2327,55 +2327,7 @@ bool DescriptorScriptPubKeyMan::SetupDescriptorGeneration(WalletBatch& batch, co
         return false;
     }
 
-    int64_t creation_time = GetTime();
+    m_wallet_descriptor = GenerateWalletDescriptor(master_key.Neuter(), addr_type, internal);
-
-    std::string xpub = EncodeExtPubKey(master_key.Neuter());
-
-    // Build descriptor string
-    std::string desc_prefix;
-    std::string desc_suffix = "/*)";
-    switch (addr_type) {
-    case OutputType::LEGACY: {
-        desc_prefix = "pkh(" + xpub + "/44h";
-        break;
-    }
-    case OutputType::P2SH_SEGWIT: {
-        desc_prefix = "sh(wpkh(" + xpub + "/49h";
-        desc_suffix += ")";
-        break;
-    }
-    case OutputType::BECH32: {
-        desc_prefix = "wpkh(" + xpub + "/84h";
-        break;
-    }
-    case OutputType::BECH32M: {
-        desc_prefix = "tr(" + xpub + "/86h";
-        break;
-    }
-    case OutputType::UNKNOWN: {
-        // We should never have a DescriptorScriptPubKeyMan for an UNKNOWN OutputType,
-        // so if we get to this point something is wrong
-        assert(false);
-    }
-    } // no default case, so the compiler can warn about missing cases
-    assert(!desc_prefix.empty());
-
-    // Mainnet derives at 0', testnet and regtest derive at 1'
-    if (Params().IsTestChain()) {
-        desc_prefix += "/1h";
-    } else {
-        desc_prefix += "/0h";
-    }
-
-    std::string internal_path = internal ? "/1" : "/0";
-    std::string desc_str = desc_prefix + "/0h" + internal_path + desc_suffix;
-
-    // Make the descriptor
-    FlatSigningProvider keys;
-    std::string error;
-    std::unique_ptr<Descriptor> desc = Parse(desc_str, keys, error, false);
-    WalletDescriptor w_desc(std::move(desc), creation_time, 0, 0, 0);
-    m_wallet_descriptor = w_desc;
 
     // Store the master private key, and descriptor
     if (!AddDescriptorKeyWithDB(batch, master_key.key, master_key.key.GetPubKey())) {

src/wallet/walletutil.cpp

@@ -4,7 +4,9 @@
 
 #include <wallet/walletutil.h>
 
+#include <chainparams.h>
 #include <common/args.h>
+#include <key_io.h>
 #include <logging.h>
 
 namespace wallet {
@@ -43,4 +45,58 @@ WalletFeature GetClosestWalletFeature(int version)
     }
     return static_cast<WalletFeature>(0);
 }
+
+WalletDescriptor GenerateWalletDescriptor(const CExtPubKey& master_key, const OutputType& addr_type, bool internal)
+{
+    int64_t creation_time = GetTime();
+
+    std::string xpub = EncodeExtPubKey(master_key);
+
+    // Build descriptor string
+    std::string desc_prefix;
+    std::string desc_suffix = "/*)";
+    switch (addr_type) {
+    case OutputType::LEGACY: {
+        desc_prefix = "pkh(" + xpub + "/44h";
+        break;
+    }
+    case OutputType::P2SH_SEGWIT: {
+        desc_prefix = "sh(wpkh(" + xpub + "/49h";
+        desc_suffix += ")";
+        break;
+    }
+    case OutputType::BECH32: {
+        desc_prefix = "wpkh(" + xpub + "/84h";
+        break;
+    }
+    case OutputType::BECH32M: {
+        desc_prefix = "tr(" + xpub + "/86h";
+        break;
+    }
+    case OutputType::UNKNOWN: {
+        // We should never have a DescriptorScriptPubKeyMan for an UNKNOWN OutputType,
+        // so if we get to this point something is wrong
+        assert(false);
+    }
+    } // no default case, so the compiler can warn about missing cases
+    assert(!desc_prefix.empty());
+
+    // Mainnet derives at 0', testnet and regtest derive at 1'
+    if (Params().IsTestChain()) {
+        desc_prefix += "/1h";
+    } else {
+        desc_prefix += "/0h";
+    }
+
+    std::string internal_path = internal ? "/1" : "/0";
+    std::string desc_str = desc_prefix + "/0h" + internal_path + desc_suffix;
+
+    // Make the descriptor
+    FlatSigningProvider keys;
+    std::string error;
+    std::unique_ptr<Descriptor> desc = Parse(desc_str, keys, error, false);
+    WalletDescriptor w_desc(std::move(desc), creation_time, 0, 0, 0);
+    return w_desc;
+}
+
 } // namespace wallet

src/wallet/walletutil.h

@@ -114,6 +114,8 @@ public:
     WalletDescriptor() {}
     WalletDescriptor(std::shared_ptr<Descriptor> descriptor, uint64_t creation_time, int32_t range_start, int32_t range_end, int32_t next_index) : descriptor(descriptor), id(DescriptorID(*descriptor)), creation_time(creation_time), range_start(range_start), range_end(range_end), next_index(next_index) { }
 };
+
+WalletDescriptor GenerateWalletDescriptor(const CExtPubKey& master_key, const OutputType& output_type, bool internal);
 } // namespace wallet
 
 #endif // BITCOIN_WALLET_WALLETUTIL_H