refactor: Move wallet methods out of chain.h and node.h

Add WalletClient interface so node interface is cleaner and don't need
wallet-specific methods.

The new NodeContext::wallet_client pointer will also be needed to eliminate
global wallet variables like ::vpwallets, because createWallet(), loadWallet(),
getWallets(), etc methods called by the GUI need a way to get a reference to
the list of open wallets if it is no longer a global variable.

Also tweaks splash screen registration for load wallet events to be delayed
until after wallet client is created.

5 files changed, 74 insertions, 80 deletions

diff --git a/src/interfaces/chain.h b/src/interfaces/chain.h
index 053d40335f..6e50ccb27a 100644
--- a/src/interfaces/chain.h
+++ b/src/interfaces/chain.h
@@ -314,24 +314,11 @@ public:
 
     //! Set mock time.
     virtual void setMockTime(int64_t time) = 0;
-
-    //! Return interfaces for accessing wallets (if any).
-    virtual std::vector<std::unique_ptr<Wallet>> getWallets() = 0;
 };
 
 //! Return implementation of Chain interface.
 std::unique_ptr<Chain> MakeChain(NodeContext& node);
 
-//! Return implementation of ChainClient interface for a wallet client. This
-//! function will be undefined in builds where ENABLE_WALLET is false.
-//!
-//! Currently, wallets are the only chain clients. But in the future, other
-//! types of chain clients could be added, such as tools for monitoring,
-//! analysis, or fee estimation. These clients need to expose their own
-//! MakeXXXClient functions returning their implementations of the ChainClient
-//! interface.
-std::unique_ptr<ChainClient> MakeWalletClient(Chain& chain, ArgsManager& args, std::vector<std::string> wallet_filenames);
-
 } // namespace interfaces
 
 #endif // BITCOIN_INTERFACES_CHAIN_H
diff --git a/src/interfaces/node.cpp b/src/interfaces/node.cpp
index 73171686eb..2c5f8627e6 100644
--- a/src/interfaces/node.cpp
+++ b/src/interfaces/node.cpp
@@ -27,6 +27,7 @@
 #include <support/allocators/secure.h>
 #include <sync.h>
 #include <txmempool.h>
+#include <util/check.h>
 #include <util/ref.h>
 #include <util/system.h>
 #include <util/translation.h>
@@ -41,16 +42,7 @@
 
 #include <boost/signals2/signal.hpp>
 
-class CWallet;
-fs::path GetWalletDir();
-std::vector<fs::path> ListWalletDir();
-std::vector<std::shared_ptr<CWallet>> GetWallets();
-std::shared_ptr<CWallet> LoadWallet(interfaces::Chain& chain, const std::string& name, bilingual_str& error, std::vector<bilingual_str>& warnings);
-WalletCreationStatus CreateWallet(interfaces::Chain& chain, const SecureString& passphrase, uint64_t wallet_creation_flags, const std::string& name, bilingual_str& error, std::vector<bilingual_str>& warnings, std::shared_ptr<CWallet>& result);
-std::unique_ptr<interfaces::Handler> HandleLoadWallet(interfaces::Node::LoadWalletFn load_wallet);
-
 namespace interfaces {
-
 namespace {
 
 class NodeImpl : public Node
@@ -239,36 +231,9 @@ public:
         LOCK(::cs_main);
         return ::ChainstateActive().CoinsTip().GetCoin(output, coin);
     }
-    std::string getWalletDir() override
-    {
-        return GetWalletDir().string();
-    }
-    std::vector<std::string> listWalletDir() override
-    {
-        std::vector<std::string> paths;
-        for (auto& path : ListWalletDir()) {
-            paths.push_back(path.string());
-        }
-        return paths;
-    }
-    std::vector<std::unique_ptr<Wallet>> getWallets() override
+    WalletClient& walletClient() override
     {
-        std::vector<std::unique_ptr<Wallet>> wallets;
-        for (auto& client : m_context->chain_clients) {
-            auto client_wallets = client->getWallets();
-            std::move(client_wallets.begin(), client_wallets.end(), std::back_inserter(wallets));
-        }
-        return wallets;
-    }
-    std::unique_ptr<Wallet> loadWallet(const std::string& name, bilingual_str& error, std::vector<bilingual_str>& warnings) override
-    {
-        return MakeWallet(LoadWallet(*m_context->chain, name, error, warnings));
-    }
-    std::unique_ptr<Wallet> createWallet(const SecureString& passphrase, uint64_t wallet_creation_flags, const std::string& name, bilingual_str& error, std::vector<bilingual_str>& warnings, WalletCreationStatus& status) override
-    {
-        std::shared_ptr<CWallet> wallet;
-        status = CreateWallet(*m_context->chain, passphrase, wallet_creation_flags, name, error, warnings, wallet);
-        return MakeWallet(wallet);
+        return *Assert(m_context->wallet_client);
     }
     std::unique_ptr<Handler> handleInitMessage(InitMessageFn fn) override
     {
@@ -286,10 +251,6 @@ public:
     {
         return MakeHandler(::uiInterface.ShowProgress_connect(fn));
     }
-    std::unique_ptr<Handler> handleLoadWallet(LoadWalletFn fn) override
-    {
-        return HandleLoadWallet(std::move(fn));
-    }
     std::unique_ptr<Handler> handleNotifyNumConnectionsChanged(NotifyNumConnectionsChangedFn fn) override
     {
         return MakeHandler(::uiInterface.NotifyNumConnectionsChanged_connect(fn));
diff --git a/src/interfaces/node.h b/src/interfaces/node.h
index 0cff7ae3a1..5079be038e 100644
--- a/src/interfaces/node.h
+++ b/src/interfaces/node.h
@@ -29,14 +29,13 @@ class RPCTimerInterface;
 class UniValue;
 class proxyType;
 enum class SynchronizationState;
-enum class WalletCreationStatus;
 struct CNodeStateStats;
 struct NodeContext;
 struct bilingual_str;
 
 namespace interfaces {
 class Handler;
-class Wallet;
+class WalletClient;
 struct BlockTip;
 
 //! Block and header tip information
@@ -173,22 +172,8 @@ public:
     //! Get unspent outputs associated with a transaction.
     virtual bool getUnspentOutput(const COutPoint& output, Coin& coin) = 0;
 
-    //! Return default wallet directory.
-    virtual std::string getWalletDir() = 0;
-
-    //! Return available wallets in wallet directory.
-    virtual std::vector<std::string> listWalletDir() = 0;
-
-    //! Return interfaces for accessing wallets (if any).
-    virtual std::vector<std::unique_ptr<Wallet>> getWallets() = 0;
-
-    //! Attempts to load a wallet from file or directory.
-    //! The loaded wallet is also notified to handlers previously registered
-    //! with handleLoadWallet.
-    virtual std::unique_ptr<Wallet> loadWallet(const std::string& name, bilingual_str& error, std::vector<bilingual_str>& warnings) = 0;
-
-    //! Create a wallet from file
-    virtual std::unique_ptr<Wallet> createWallet(const SecureString& passphrase, uint64_t wallet_creation_flags, const std::string& name, bilingual_str& error, std::vector<bilingual_str>& warnings, WalletCreationStatus& status) = 0;
+    //! Get wallet client.
+    virtual WalletClient& walletClient() = 0;
 
     //! Register handler for init messages.
     using InitMessageFn = std::function<void(const std::string& message)>;
@@ -210,10 +195,6 @@ public:
     using ShowProgressFn = std::function<void(const std::string& title, int progress, bool resume_possible)>;
     virtual std::unique_ptr<Handler> handleShowProgress(ShowProgressFn fn) = 0;
 
-    //! Register handler for load wallet messages.
-    using LoadWalletFn = std::function<void(std::unique_ptr<Wallet> wallet)>;
-    virtual std::unique_ptr<Handler> handleLoadWallet(LoadWalletFn fn) = 0;
-
     //! Register handler for number of connections changed messages.
     using NotifyNumConnectionsChangedFn = std::function<void(int new_num_connections)>;
     virtual std::unique_ptr<Handler> handleNotifyNumConnectionsChanged(NotifyNumConnectionsChangedFn fn) = 0;
diff --git a/src/interfaces/wallet.cpp b/src/interfaces/wallet.cpp
index 937e602fb0..63c109658e 100644
--- a/src/interfaces/wallet.cpp
+++ b/src/interfaces/wallet.cpp
@@ -485,7 +485,7 @@ public:
     std::shared_ptr<CWallet> m_wallet;
 };
 
-class WalletClientImpl : public ChainClient
+class WalletClientImpl : public WalletClient
 {
 public:
     WalletClientImpl(Chain& chain, ArgsManager& args, std::vector<std::string> wallet_filenames)
@@ -494,6 +494,9 @@ public:
         m_context.chain = &chain;
         m_context.args = &args;
     }
+    ~WalletClientImpl() override { UnloadWallets(); }
+
+    //! ChainClient methods
     void registerRpcs() override
     {
         for (const CRPCCommand& command : GetWalletRPCCommands()) {
@@ -509,6 +512,30 @@ public:
     void flush() override { return FlushWallets(); }
     void stop() override { return StopWallets(); }
     void setMockTime(int64_t time) override { return SetMockTime(time); }
+
+    //! WalletClient methods
+    std::unique_ptr<Wallet> createWallet(const std::string& name, const SecureString& passphrase, uint64_t wallet_creation_flags, WalletCreationStatus& status, bilingual_str& error, std::vector<bilingual_str>& warnings) override
+    {
+        std::shared_ptr<CWallet> wallet;
+        status = CreateWallet(*m_context.chain, passphrase, wallet_creation_flags, name, error, warnings, wallet);
+        return MakeWallet(std::move(wallet));
+    }
+    std::unique_ptr<Wallet> loadWallet(const std::string& name, bilingual_str& error, std::vector<bilingual_str>& warnings) override
+    {
+        return MakeWallet(LoadWallet(*m_context.chain, WalletLocation(name), error, warnings));
+    }
+    std::string getWalletDir() override
+    {
+        return GetWalletDir().string();
+    }
+    std::vector<std::string> listWalletDir() override
+    {
+        std::vector<std::string> paths;
+        for (auto& path : ListWalletDir()) {
+            paths.push_back(path.string());
+        }
+        return paths;
+    }
     std::vector<std::unique_ptr<Wallet>> getWallets() override
     {
         std::vector<std::unique_ptr<Wallet>> wallets;
@@ -517,7 +544,10 @@ public:
         }
         return wallets;
     }
-    ~WalletClientImpl() override { UnloadWallets(); }
+    std::unique_ptr<Handler> handleLoadWallet(LoadWalletFn fn) override
+    {
+        return HandleLoadWallet(std::move(fn));
+    }
 
     WalletContext m_context;
     const std::vector<std::string> m_wallet_filenames;
@@ -529,7 +559,7 @@ public:
 
 std::unique_ptr<Wallet> MakeWallet(const std::shared_ptr<CWallet>& wallet) { return wallet ? MakeUnique<WalletImpl>(wallet) : nullptr; }
 
-std::unique_ptr<ChainClient> MakeWalletClient(Chain& chain, ArgsManager& args, std::vector<std::string> wallet_filenames)
+std::unique_ptr<WalletClient> MakeWalletClient(Chain& chain, ArgsManager& args, std::vector<std::string> wallet_filenames)
 {
     return MakeUnique<WalletClientImpl>(chain, args, std::move(wallet_filenames));
 }
diff --git a/src/interfaces/wallet.h b/src/interfaces/wallet.h
index 3cdadbc72e..186f5d81a5 100644
--- a/src/interfaces/wallet.h
+++ b/src/interfaces/wallet.h
@@ -6,6 +6,7 @@
 #define BITCOIN_INTERFACES_WALLET_H
 
 #include <amount.h>                    // For CAmount
+#include <interfaces/chain.h>          // For ChainClient
 #include <pubkey.h>                    // For CKeyID and CScriptID (definitions needed in CTxDestination instantiation)
 #include <script/standard.h>           // For CTxDestination
 #include <support/allocators/secure.h> // For SecureString
@@ -28,9 +29,11 @@ class CWallet;
 enum class FeeReason;
 enum class OutputType;
 enum class TransactionError;
+enum class WalletCreationStatus;
 enum isminetype : unsigned int;
 struct CRecipient;
 struct PartiallySignedTransaction;
+struct WalletContext;
 struct bilingual_str;
 typedef uint8_t isminefilter;
 
@@ -301,6 +304,34 @@ public:
     virtual CWallet* wallet() { return nullptr; }
 };
 
+//! Wallet chain client that in addition to having chain client methods for
+//! starting up, shutting down, and registering RPCs, also has additional
+//! methods (called by the GUI) to load and create wallets.
+class WalletClient : public ChainClient
+{
+public:
+    //! Create new wallet.
+    virtual std::unique_ptr<Wallet> createWallet(const std::string& name, const SecureString& passphrase, uint64_t wallet_creation_flags, WalletCreationStatus& status, bilingual_str& error, std::vector<bilingual_str>& warnings) = 0;
+
+   //! Load existing wallet.
+   virtual std::unique_ptr<Wallet> loadWallet(const std::string& name, bilingual_str& error, std::vector<bilingual_str>& warnings) = 0;
+
+   //! Return default wallet directory.
+   virtual std::string getWalletDir() = 0;
+
+   //! Return available wallets in wallet directory.
+   virtual std::vector<std::string> listWalletDir() = 0;
+
+   //! Return interfaces for accessing wallets (if any).
+   virtual std::vector<std::unique_ptr<Wallet>> getWallets() = 0;
+
+   //! Register handler for load wallet messages. This callback is triggered by
+   //! createWallet and loadWallet above, and also triggered when wallets are
+   //! loaded at startup or by RPC.
+   using LoadWalletFn = std::function<void(std::unique_ptr<Wallet> wallet)>;
+   virtual std::unique_ptr<Handler> handleLoadWallet(LoadWalletFn fn) = 0;
+};
+
 //! Information about one wallet address.
 struct WalletAddress
 {
@@ -379,6 +410,10 @@ struct WalletTxOut
 //! dummywallet.cpp and throws if the wallet component is not compiled.
 std::unique_ptr<Wallet> MakeWallet(const std::shared_ptr<CWallet>& wallet);
 
+//! Return implementation of ChainClient interface for a wallet client. This
+//! function will be undefined in builds where ENABLE_WALLET is false.
+std::unique_ptr<WalletClient> MakeWalletClient(Chain& chain, ArgsManager& args, std::vector<std::string> wallet_filenames);
+
 } // namespace interfaces
 
 #endif // BITCOIN_INTERFACES_WALLET_H