Merge #16244: Move wallet creation out of the createwallet rpc into its own function

1aecdf2063cbe28d4715ae5ae1a7e51b860c9f4d Move wallet creation out of the createwallet rpc into its own function (Andrew Chow)

Pull request description:

  Moves the wallet creation logic from within the `createwallet` rpc and into its own function within wallet.cpp.

ACKs for top commit:
  jnewbery:
    ACK 1aecdf2063cbe28d4715ae5ae1a7e51b860c9f4d
  MarcoFalke:
    ACK 1aecdf2063cbe28d4715ae5ae1a7e51b860c9f4d
  Sjors:
    ACK 1aecdf2 with some suggestions for followup.

Tree-SHA512: 8d26d7ff48db4f8fac12408a5a294f788b7f50a72e7eb4008fb74ff14d7400eb3970f8038a19f989eff55198fc11c0cf86f52231c62b9015eb777132edc8ea88

3 files changed, 82 insertions, 46 deletions

diff --git a/src/wallet/rpcwallet.cpp b/src/wallet/rpcwallet.cpp
index 27fb009070..87ef58ee96 100644
--- a/src/wallet/rpcwallet.cpp
+++ b/src/wallet/rpcwallet.cpp
@@ -2660,17 +2660,12 @@ static UniValue createwallet(const JSONRPCRequest& request)
         },
     }.Check(request);
 
-    std::string error;
-    std::string warning;
-
     uint64_t flags = 0;
     if (!request.params[1].isNull() && request.params[1].get_bool()) {
         flags |= WALLET_FLAG_DISABLE_PRIVATE_KEYS;
     }
 
-    bool create_blank = false; // Indicate that the wallet is actually supposed to be blank and not just blank to make it encrypted
     if (!request.params[2].isNull() && request.params[2].get_bool()) {
-        create_blank = true;
         flags |= WALLET_FLAG_BLANK_WALLET;
     }
     SecureString passphrase;
@@ -2681,55 +2676,24 @@ static UniValue createwallet(const JSONRPCRequest& request)
             // Empty string is invalid
             throw JSONRPCError(RPC_WALLET_ENCRYPTION_FAILED, "Cannot encrypt a wallet with a blank password");
         }
-        // Born encrypted wallets need to be blank first so that wallet creation doesn't make any unencrypted keys
-        flags |= WALLET_FLAG_BLANK_WALLET;
     }
 
     if (!request.params[4].isNull() && request.params[4].get_bool()) {
         flags |= WALLET_FLAG_AVOID_REUSE;
     }
 
-    WalletLocation location(request.params[0].get_str());
-    if (location.Exists()) {
-        throw JSONRPCError(RPC_WALLET_ERROR, "Wallet " + location.GetName() + " already exists.");
-    }
-
-    // Wallet::Verify will check if we're trying to create a wallet with a duplication name.
-    if (!CWallet::Verify(*g_rpc_interfaces->chain, location, false, error, warning)) {
-        throw JSONRPCError(RPC_WALLET_ERROR, "Wallet file verification failed: " + error);
-    }
-
-    std::shared_ptr<CWallet> const wallet = CWallet::CreateWalletFromFile(*g_rpc_interfaces->chain, location, flags);
-    if (!wallet) {
-        throw JSONRPCError(RPC_WALLET_ERROR, "Wallet creation failed.");
-    }
-
-    // Encrypt the wallet if there's a passphrase
-    if (!passphrase.empty() && !(flags & WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
-        if (!wallet->EncryptWallet(passphrase)) {
-            throw JSONRPCError(RPC_WALLET_ENCRYPTION_FAILED, "Error: Wallet created but failed to encrypt.");
-        }
-
-        if (!create_blank) {
-            // Unlock the wallet
-            if (!wallet->Unlock(passphrase)) {
-                throw JSONRPCError(RPC_WALLET_ENCRYPTION_FAILED, "Error: Wallet was encrypted but could not be unlocked");
-            }
-
-            // Set a seed for the wallet
-            CPubKey master_pub_key = wallet->GenerateNewSeed();
-            wallet->SetHDSeed(master_pub_key);
-            wallet->NewKeyPool();
-
-            // Relock the wallet
-            wallet->Lock();
-        }
+    std::string error;
+    std::string warning;
+    WalletCreationStatus status;
+    std::shared_ptr<CWallet> wallet = CreateWallet(*g_rpc_interfaces->chain, request.params[0].get_str(), error, warning, status, passphrase, flags);
+    if (status == WalletCreationStatus::CREATION_FAILED) {
+        throw JSONRPCError(RPC_WALLET_ERROR, error);
+    } else if (status == WalletCreationStatus::ENCRYPTION_FAILED) {
+        throw JSONRPCError(RPC_WALLET_ENCRYPTION_FAILED, error);
+    } else if (status != WalletCreationStatus::SUCCESS) {
+        throw JSONRPCError(RPC_WALLET_ERROR, "Wallet creation failed");
     }
 
-    AddWallet(wallet);
-
-    wallet->postInitProcess();
-
     UniValue obj(UniValue::VOBJ);
     obj.pushKV("name", wallet->GetName());
     obj.pushKV("warning", warning);
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 5fb883d48b..e53b433ca8 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -160,6 +160,70 @@ std::shared_ptr<CWallet> LoadWallet(interfaces::Chain& chain, const std::string&
     return LoadWallet(chain, WalletLocation(name), error, warning);
 }
 
+std::shared_ptr<CWallet> CreateWallet(interfaces::Chain& chain, const std::string& name, std::string& error, std::string& warning, WalletCreationStatus& status, const SecureString& passphrase, uint64_t wallet_creation_flags)
+{
+    // Indicate that the wallet is actually supposed to be blank and not just blank to make it encrypted
+    bool create_blank = (wallet_creation_flags & WALLET_FLAG_BLANK_WALLET);
+
+    // Born encrypted wallets need to be created blank first.
+    if (!passphrase.empty()) {
+        wallet_creation_flags |= WALLET_FLAG_BLANK_WALLET;
+    }
+
+    // Check the wallet file location
+    WalletLocation location(name);
+    if (location.Exists()) {
+        error = "Wallet " + location.GetName() + " already exists.";
+        status = WalletCreationStatus::CREATION_FAILED;
+        return nullptr;
+    }
+
+    // Wallet::Verify will check if we're trying to create a wallet with a duplicate name.
+    std::string wallet_error;
+    if (!CWallet::Verify(chain, location, false, wallet_error, warning)) {
+        error = "Wallet file verification failed: " + wallet_error;
+        status = WalletCreationStatus::CREATION_FAILED;
+        return nullptr;
+    }
+
+    // Make the wallet
+    std::shared_ptr<CWallet> wallet = CWallet::CreateWalletFromFile(chain, location, wallet_creation_flags);
+    if (!wallet) {
+        error = "Wallet creation failed";
+        status = WalletCreationStatus::CREATION_FAILED;
+        return nullptr;
+    }
+
+    // Encrypt the wallet
+    if (!passphrase.empty() && !(wallet_creation_flags & WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
+        if (!wallet->EncryptWallet(passphrase)) {
+            error = "Error: Wallet created but failed to encrypt.";
+            status = WalletCreationStatus::ENCRYPTION_FAILED;
+            return nullptr;
+        }
+        if (!create_blank) {
+            // Unlock the wallet
+            if (!wallet->Unlock(passphrase)) {
+                error = "Error: Wallet was encrypted but could not be unlocked";
+                status = WalletCreationStatus::ENCRYPTION_FAILED;
+                return nullptr;
+            }
+
+            // Set a seed for the wallet
+            CPubKey master_pub_key = wallet->GenerateNewSeed();
+            wallet->SetHDSeed(master_pub_key);
+            wallet->NewKeyPool();
+
+            // Relock the wallet
+            wallet->Lock();
+        }
+    }
+    AddWallet(wallet);
+    wallet->postInitProcess();
+    status = WalletCreationStatus::SUCCESS;
+    return wallet;
+}
+
 const uint32_t BIP32_HARDENED_KEY_LIMIT = 0x80000000;
 
 const uint256 CMerkleTx::ABANDON_HASH(uint256S("0000000000000000000000000000000000000000000000000000000000000001"));
diff --git a/src/wallet/wallet.h b/src/wallet/wallet.h
index 14c373bddf..7e2230554d 100644
--- a/src/wallet/wallet.h
+++ b/src/wallet/wallet.h
@@ -49,6 +49,14 @@ std::vector<std::shared_ptr<CWallet>> GetWallets();
 std::shared_ptr<CWallet> GetWallet(const std::string& name);
 std::shared_ptr<CWallet> LoadWallet(interfaces::Chain& chain, const WalletLocation& location, std::string& error, std::string& warning);
 
+enum WalletCreationStatus {
+    SUCCESS,
+    CREATION_FAILED,
+    ENCRYPTION_FAILED
+};
+
+std::shared_ptr<CWallet> CreateWallet(interfaces::Chain& chain, const std::string& name, std::string& error, std::string& warning, WalletCreationStatus& status, const SecureString& passphrase, uint64_t wallet_creation_flags);
+
 //! Default for -keypool
 static const unsigned int DEFAULT_KEYPOOL_SIZE = 1000;
 //! -paytxfee default