Initial Vexta Core v0.1.0 release

src/interfaces/README.md

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+# Internal c++ interfaces
+
+The following interfaces are defined here:
+
+* [`Chain`](chain.h) — used by wallet to access blockchain and mempool state. Added in [#14437](https://github.com/digibyte/digibyte/pull/14437), [#14711](https://github.com/digibyte/digibyte/pull/14711), [#15288](https://github.com/digibyte/digibyte/pull/15288), and [#10973](https://github.com/digibyte/digibyte/pull/10973).
+
+* [`ChainClient`](chain.h) — used by node to start & stop `Chain` clients. Added in [#14437](https://github.com/digibyte/digibyte/pull/14437).
+
+* [`Node`](node.h) — used by GUI to start & stop digibyte node. Added in [#10244](https://github.com/digibyte/digibyte/pull/10244).
+
+* [`Wallet`](wallet.h) — used by GUI to access wallets. Added in [#10244](https://github.com/digibyte/digibyte/pull/10244).
+
+* [`Handler`](handler.h) — returned by `handleEvent` methods on interfaces above and used to manage lifetimes of event handlers.
+
+* [`Init`](init.h) — used by multiprocess code to access interfaces above on startup. Added in [#19160](https://github.com/digibyte/digibyte/pull/19160).
+
+* [`Ipc`](ipc.h) — used by multiprocess code to access `Init` interface across processes. Added in [#19160](https://github.com/digibyte/digibyte/pull/19160).
+
+The interfaces above define boundaries between major components of digibyte code (node, wallet, and gui), making it possible for them to run in [different processes](../../doc/multiprocess.md), and be tested, developed, and understood independently. These interfaces are not currently designed to be stable or to be used externally.

src/interfaces/chain.h

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+// Copyright (c) 2018-2020 The DigiByte Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef DIGIBYTE_INTERFACES_CHAIN_H
+#define DIGIBYTE_INTERFACES_CHAIN_H
+
+#include <primitives/transaction.h> // For CTransactionRef
+#include <util/settings.h>          // For util::SettingsValue
+
+#include <functional>
+#include <memory>
+#include <optional>
+#include <stddef.h>
+#include <stdint.h>
+#include <string>
+#include <vector>
+
+class ArgsManager;
+class CBlock;
+class CFeeRate;
+class CRPCCommand;
+class CScheduler;
+class Coin;
+class uint256;
+enum class MemPoolRemovalReason;
+enum class RBFTransactionState;
+struct bilingual_str;
+struct CBlockLocator;
+struct FeeCalculation;
+struct NodeContext;
+
+namespace interfaces {
+
+class Handler;
+class Wallet;
+
+//! Helper for findBlock to selectively return pieces of block data.
+class FoundBlock
+{
+public:
+    FoundBlock& hash(uint256& hash) { m_hash = &hash; return *this; }
+    FoundBlock& height(int& height) { m_height = &height; return *this; }
+    FoundBlock& time(int64_t& time) { m_time = &time; return *this; }
+    FoundBlock& maxTime(int64_t& max_time) { m_max_time = &max_time; return *this; }
+    FoundBlock& mtpTime(int64_t& mtp_time) { m_mtp_time = &mtp_time; return *this; }
+    //! Return whether block is in the active (most-work) chain.
+    FoundBlock& inActiveChain(bool& in_active_chain) { m_in_active_chain = &in_active_chain; return *this; }
+    //! Return next block in the active chain if current block is in the active chain.
+    FoundBlock& nextBlock(const FoundBlock& next_block) { m_next_block = &next_block; return *this; }
+    //! Read block data from disk. If the block exists but doesn't have data
+    //! (for example due to pruning), the CBlock variable will be set to null.
+    FoundBlock& data(CBlock& data) { m_data = &data; return *this; }
+
+    uint256* m_hash = nullptr;
+    int* m_height = nullptr;
+    int64_t* m_time = nullptr;
+    int64_t* m_max_time = nullptr;
+    int64_t* m_mtp_time = nullptr;
+    bool* m_in_active_chain = nullptr;
+    const FoundBlock* m_next_block = nullptr;
+    CBlock* m_data = nullptr;
+};
+
+//! Interface giving clients (wallet processes, maybe other analysis tools in
+//! the future) ability to access to the chain state, receive notifications,
+//! estimate fees, and submit transactions.
+//!
+//! TODO: Current chain methods are too low level, exposing too much of the
+//! internal workings of the Vexta node, and not being very convenient to use.
+//! Chain methods should be cleaned up and simplified over time. Examples:
+//!
+//! * The initMessages() and showProgress() methods which the wallet uses to send
+//!   notifications to the GUI should go away when GUI and wallet can directly
+//!   communicate with each other without going through the node
+//!   (https://github.com/digibyte/digibyte/pull/15288#discussion_r253321096).
+//!
+//! * The handleRpc, registerRpcs, rpcEnableDeprecated methods and other RPC
+//!   methods can go away if wallets listen for HTTP requests on their own
+//!   ports instead of registering to handle requests on the node HTTP port.
+//!
+//! * Move fee estimation queries to an asynchronous interface and let the
+//!   wallet cache it, fee estimation being driven by node mempool, wallet
+//!   should be the consumer.
+//!
+//! * `guessVerificationProgress` and similar methods can go away if rescan
+//!   logic moves out of the wallet, and the wallet just requests scans from the
+//!   node (https://github.com/digibyte/digibyte/issues/11756)
+class Chain
+{
+public:
+    virtual ~Chain() {}
+
+    //! Get current chain height, not including genesis block (returns 0 if
+    //! chain only contains genesis block, nullopt if chain does not contain
+    //! any blocks)
+    virtual std::optional<int> getHeight() = 0;
+
+    //! Get block hash. Height must be valid or this function will abort.
+    virtual uint256 getBlockHash(int height) = 0;
+
+    //! Check that the block is available on disk (i.e. has not been
+    //! pruned), and contains transactions.
+    virtual bool haveBlockOnDisk(int height) = 0;
+
+    //! Get locator for the current chain tip.
+    virtual CBlockLocator getTipLocator() = 0;
+
+    //! Return height of the highest block on chain in common with the locator,
+    //! which will either be the original block used to create the locator,
+    //! or one of its ancestors.
+    virtual std::optional<int> findLocatorFork(const CBlockLocator& locator) = 0;
+
+    //! Check if transaction will be final given chain height current time.
+    virtual bool checkFinalTx(const CTransaction& tx) = 0;
+
+    //! Return whether node has the block and optionally return block metadata
+    //! or contents.
+    virtual bool findBlock(const uint256& hash, const FoundBlock& block={}) = 0;
+
+    //! Find first block in the chain with timestamp >= the given time
+    //! and height >= than the given height, return false if there is no block
+    //! with a high enough timestamp and height. Optionally return block
+    //! information.
+    virtual bool findFirstBlockWithTimeAndHeight(int64_t min_time, int min_height, const FoundBlock& block={}) = 0;
+
+    //! Find ancestor of block at specified height and optionally return
+    //! ancestor information.
+    virtual bool findAncestorByHeight(const uint256& block_hash, int ancestor_height, const FoundBlock& ancestor_out={}) = 0;
+
+    //! Return whether block descends from a specified ancestor, and
+    //! optionally return ancestor information.
+    virtual bool findAncestorByHash(const uint256& block_hash,
+        const uint256& ancestor_hash,
+        const FoundBlock& ancestor_out={}) = 0;
+
+    //! Find most recent common ancestor between two blocks and optionally
+    //! return block information.
+    virtual bool findCommonAncestor(const uint256& block_hash1,
+        const uint256& block_hash2,
+        const FoundBlock& ancestor_out={},
+        const FoundBlock& block1_out={},
+        const FoundBlock& block2_out={}) = 0;
+
+    //! Look up unspent output information. Returns coins in the mempool and in
+    //! the current chain UTXO set. Iterates through all the keys in the map and
+    //! populates the values.
+    virtual void findCoins(std::map<COutPoint, Coin>& coins) = 0;
+
+    //! Estimate fraction of total transactions verified if blocks up to
+    //! the specified block hash are verified.
+    virtual double guessVerificationProgress(const uint256& block_hash) = 0;
+
+    //! Return true if data is available for all blocks in the specified range
+    //! of blocks. This checks all blocks that are ancestors of block_hash in
+    //! the height range from min_height to max_height, inclusive.
+    virtual bool hasBlocks(const uint256& block_hash, int min_height = 0, std::optional<int> max_height = {}) = 0;
+
+    //! Check if transaction is RBF opt in.
+    virtual RBFTransactionState isRBFOptIn(const CTransaction& tx) = 0;
+
+    //! Check if transaction is in mempool.
+    virtual bool isInMempool(const uint256& txid) = 0;
+
+    //! Check if transaction has descendants in mempool.
+    virtual bool hasDescendantsInMempool(const uint256& txid) = 0;
+
+    //! Transaction is added to memory pool, if the transaction fee is below the
+    //! amount specified by max_tx_fee, and broadcast to all peers if relay is set to true.
+    //! Return false if the transaction could not be added due to the fee or for another reason.
+    virtual bool broadcastTransaction(const CTransactionRef& tx,
+        const CAmount& max_tx_fee,
+        bool relay,
+        std::string& err_string) = 0;
+
+    //! Calculate mempool ancestor and descendant counts for the given transaction.
+    virtual void getTransactionAncestry(const uint256& txid, size_t& ancestors, size_t& descendants) = 0;
+
+    //! Get the node's package limits.
+    //! Currently only returns the ancestor and descendant count limits, but could be enhanced to
+    //! return more policy settings.
+    virtual void getPackageLimits(unsigned int& limit_ancestor_count, unsigned int& limit_descendant_count) = 0;
+
+    //! Check if transaction will pass the mempool's chain limits.
+    virtual bool checkChainLimits(const CTransactionRef& tx) = 0;
+
+    //! Estimate smart fee.
+    virtual CFeeRate estimateSmartFee(int num_blocks, bool conservative, FeeCalculation* calc = nullptr) = 0;
+
+    //! Fee estimator max target.
+    virtual unsigned int estimateMaxBlocks() = 0;
+
+    //! Mempool minimum fee.
+    virtual CFeeRate mempoolMinFee() = 0;
+
+    //! Relay current minimum fee (from -minrelaytxfee and -incrementalrelayfee settings).
+    virtual CFeeRate relayMinFee() = 0;
+
+    //! Relay incremental fee setting (-incrementalrelayfee), reflecting cost of relay.
+    virtual CFeeRate relayIncrementalFee() = 0;
+
+    //! Relay dust fee setting (-dustrelayfee), reflecting lowest rate it's economical to spend.
+    virtual CFeeRate relayDustFee() = 0;
+
+    //! Check if any block has been pruned.
+    virtual bool havePruned() = 0;
+
+    //! Check if the node is ready to broadcast transactions.
+    virtual bool isReadyToBroadcast() = 0;
+
+    //! Check if in IBD.
+    virtual bool isInitialBlockDownload() = 0;
+
+    //! Check if shutdown requested.
+    virtual bool shutdownRequested() = 0;
+
+    //! Get adjusted time.
+    virtual int64_t getAdjustedTime() = 0;
+
+    //! Send init message.
+    virtual void initMessage(const std::string& message) = 0;
+
+    //! Send init warning.
+    virtual void initWarning(const bilingual_str& message) = 0;
+
+    //! Send init error.
+    virtual void initError(const bilingual_str& message) = 0;
+
+    //! Send progress indicator.
+    virtual void showProgress(const std::string& title, int progress, bool resume_possible) = 0;
+
+    //! Chain notifications.
+    class Notifications
+    {
+    public:
+        virtual ~Notifications() {}
+        virtual void transactionAddedToMempool(const CTransactionRef& tx, uint64_t mempool_sequence) {}
+        virtual void transactionRemovedFromMempool(const CTransactionRef& tx, MemPoolRemovalReason reason, uint64_t mempool_sequence) {}
+        virtual void blockConnected(const CBlock& block, int height) {}
+        virtual void blockDisconnected(const CBlock& block, int height) {}
+        virtual void updatedBlockTip() {}
+        virtual void chainStateFlushed(const CBlockLocator& locator) {}
+    };
+
+    //! Register handler for notifications.
+    virtual std::unique_ptr<Handler> handleNotifications(std::shared_ptr<Notifications> notifications) = 0;
+
+    //! Wait for pending notifications to be processed unless block hash points to the current
+    //! chain tip.
+    virtual void waitForNotificationsIfTipChanged(const uint256& old_tip) = 0;
+
+    //! Register handler for RPC. Command is not copied, so reference
+    //! needs to remain valid until Handler is disconnected.
+    virtual std::unique_ptr<Handler> handleRpc(const CRPCCommand& command) = 0;
+
+    //! Check if deprecated RPC is enabled.
+    virtual bool rpcEnableDeprecated(const std::string& method) = 0;
+
+    //! Run function after given number of seconds. Cancel any previous calls with same name.
+    virtual void rpcRunLater(const std::string& name, std::function<void()> fn, int64_t seconds) = 0;
+
+    //! Current RPC serialization flags.
+    virtual int rpcSerializationFlags() = 0;
+
+    //! Return <datadir>/settings.json setting value.
+    virtual util::SettingsValue getRwSetting(const std::string& name) = 0;
+
+    //! Write a setting to <datadir>/settings.json.
+    virtual bool updateRwSetting(const std::string& name, const util::SettingsValue& value) = 0;
+
+    //! Synchronously send transactionAddedToMempool notifications about all
+    //! current mempool transactions to the specified handler and return after
+    //! the last one is sent. These notifications aren't coordinated with async
+    //! notifications sent by handleNotifications, so out of date async
+    //! notifications from handleNotifications can arrive during and after
+    //! synchronous notifications from requestMempoolTransactions. Clients need
+    //! to be prepared to handle this by ignoring notifications about unknown
+    //! removed transactions and already added new transactions.
+    virtual void requestMempoolTransactions(Notifications& notifications) = 0;
+
+    //! Check if Taproot has activated
+    virtual bool isTaprootActive() const = 0;
+};
+
+//! Interface to let node manage chain clients (wallets, or maybe tools for
+//! monitoring and analysis in the future).
+class ChainClient
+{
+public:
+    virtual ~ChainClient() {}
+
+    //! Register rpcs.
+    virtual void registerRpcs() = 0;
+
+    //! Check for errors before loading.
+    virtual bool verify() = 0;
+
+    //! Load saved state.
+    virtual bool load() = 0;
+
+    //! Start client execution and provide a scheduler.
+    virtual void start(CScheduler& scheduler) = 0;
+
+    //! Save state to disk.
+    virtual void flush() = 0;
+
+    //! Shut down client.
+    virtual void stop() = 0;
+
+    //! Set mock time.
+    virtual void setMockTime(int64_t time) = 0;
+};
+
+//! Return implementation of Chain interface.
+std::unique_ptr<Chain> MakeChain(NodeContext& node);
+
+} // namespace interfaces
+
+#endif // DIGIBYTE_INTERFACES_CHAIN_H

src/interfaces/echo.cpp

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+// Copyright (c) 2021 The DigiByte Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <interfaces/echo.h>
+
+#include <memory>
+
+namespace interfaces {
+namespace {
+class EchoImpl : public Echo
+{
+public:
+    std::string echo(const std::string& echo) override { return echo; }
+};
+} // namespace
+std::unique_ptr<Echo> MakeEcho() { return std::make_unique<EchoImpl>(); }
+} // namespace interfaces

src/interfaces/echo.h

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+// Copyright (c) 2021 The DigiByte Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef DIGIBYTE_INTERFACES_ECHO_H
+#define DIGIBYTE_INTERFACES_ECHO_H
+
+#include <memory>
+#include <string>
+
+namespace interfaces {
+//! Simple string echoing interface for testing.
+class Echo
+{
+public:
+    virtual ~Echo() {}
+
+    //! Echo provided string.
+    virtual std::string echo(const std::string& echo) = 0;
+};
+
+//! Return implementation of Echo interface.
+std::unique_ptr<Echo> MakeEcho();
+} // namespace interfaces
+
+#endif // DIGIBYTE_INTERFACES_ECHO_H

src/interfaces/handler.cpp

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+// Copyright (c) 2018-2020 The Bitcoin Core developers
+// Copyright (c) 2018-2020 The DigiByte Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <interfaces/handler.h>
+
+
+#include <boost/signals2/connection.hpp>
+#include <utility>
+
+namespace interfaces {
+namespace {
+
+class HandlerImpl : public Handler
+{
+public:
+    explicit HandlerImpl(boost::signals2::connection connection) : m_connection(std::move(connection)) {}
+
+    void disconnect() override { m_connection.disconnect(); }
+
+    boost::signals2::scoped_connection m_connection;
+};
+
+class CleanupHandler : public Handler
+{
+public:
+    explicit CleanupHandler(std::function<void()> cleanup) : m_cleanup(std::move(cleanup)) {}
+    ~CleanupHandler() override { if (!m_cleanup) return; m_cleanup(); m_cleanup = nullptr; }
+    void disconnect() override { if (!m_cleanup) return; m_cleanup(); m_cleanup = nullptr; }
+    std::function<void()> m_cleanup;
+};
+
+} // namespace
+
+std::unique_ptr<Handler> MakeHandler(boost::signals2::connection connection)
+{
+    return std::make_unique<HandlerImpl>(std::move(connection));
+}
+
+std::unique_ptr<Handler> MakeHandler(std::function<void()> cleanup)
+{
+    return std::make_unique<CleanupHandler>(std::move(cleanup));
+}
+
+} // namespace interfaces

src/interfaces/handler.h

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+// Copyright (c) 2018-2020 The Bitcoin Core developers
+// Copyright (c) 2018-2020 The DigiByte Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef DIGIBYTE_INTERFACES_HANDLER_H
+#define DIGIBYTE_INTERFACES_HANDLER_H
+
+#include <functional>
+#include <memory>
+
+namespace boost {
+namespace signals2 {
+class connection;
+} // namespace signals2
+} // namespace boost
+
+namespace interfaces {
+
+//! Generic interface for managing an event handler or callback function
+//! registered with another interface. Has a single disconnect method to cancel
+//! the registration and prevent any future notifications.
+class Handler
+{
+public:
+    virtual ~Handler() {}
+
+    //! Disconnect the handler.
+    virtual void disconnect() = 0;
+};
+
+//! Return handler wrapping a boost signal connection.
+std::unique_ptr<Handler> MakeHandler(boost::signals2::connection connection);
+
+//! Return handler wrapping a cleanup function.
+std::unique_ptr<Handler> MakeHandler(std::function<void()> cleanup);
+
+} // namespace interfaces
+
+#endif // DIGIBYTE_INTERFACES_HANDLER_H

src/interfaces/init.cpp

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+// Copyright (c) 2021 The DigiByte Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <interfaces/chain.h>
+#include <interfaces/echo.h>
+#include <interfaces/init.h>
+#include <interfaces/node.h>
+#include <interfaces/wallet.h>
+
+namespace interfaces {
+std::unique_ptr<Node> Init::makeNode() { return {}; }
+std::unique_ptr<Chain> Init::makeChain() { return {}; }
+std::unique_ptr<WalletClient> Init::makeWalletClient(Chain& chain) { return {}; }
+std::unique_ptr<Echo> Init::makeEcho() { return {}; }
+Ipc* Init::ipc() { return nullptr; }
+} // namespace interfaces

src/interfaces/init.h

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+// Copyright (c) 2021 The DigiByte Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef DIGIBYTE_INTERFACES_INIT_H
+#define DIGIBYTE_INTERFACES_INIT_H
+
+#include <memory>
+
+struct NodeContext;
+
+namespace interfaces {
+class Chain;
+class Echo;
+class Ipc;
+class Node;
+class WalletClient;
+
+//! Initial interface created when a process is first started, and used to give
+//! and get access to other interfaces (Node, Chain, Wallet, etc).
+//!
+//! There is a different Init interface implementation for each process
+//! (vexta-gui, vexta-node, digibyte-wallet, vextad, vexta-qt) and each
+//! implementation can implement the make methods for interfaces it supports.
+//! The default make methods all return null.
+class Init
+{
+public:
+    virtual ~Init() = default;
+    virtual std::unique_ptr<Node> makeNode();
+    virtual std::unique_ptr<Chain> makeChain();
+    virtual std::unique_ptr<WalletClient> makeWalletClient(Chain& chain);
+    virtual std::unique_ptr<Echo> makeEcho();
+    virtual Ipc* ipc();
+};
+
+//! Return implementation of Init interface for the node process. If the argv
+//! indicates that this is a child process spawned to handle requests from a
+//! parent process, this blocks and handles requests, then returns null and a
+//! status code to exit with. If this returns non-null, the caller can start up
+//! normally and use the Init object to spawn and connect to other processes
+//! while it is running.
+std::unique_ptr<Init> MakeNodeInit(NodeContext& node, int argc, char* argv[], int& exit_status);
+
+//! Return implementation of Init interface for the wallet process.
+std::unique_ptr<Init> MakeWalletInit(int argc, char* argv[], int& exit_status);
+
+//! Return implementation of Init interface for the gui process.
+std::unique_ptr<Init> MakeGuiInit(int argc, char* argv[]);
+} // namespace interfaces
+
+#endif // DIGIBYTE_INTERFACES_INIT_H

src/interfaces/ipc.h

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+// Copyright (c) 2021 The DigiByte Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef DIGIBYTE_INTERFACES_IPC_H
+#define DIGIBYTE_INTERFACES_IPC_H
+
+#include <functional>
+#include <memory>
+#include <typeindex>
+
+namespace interfaces {
+class Init;
+
+//! Interface providing access to interprocess-communication (IPC)
+//! functionality. The IPC implementation is responsible for establishing
+//! connections between a controlling process and a process being controlled.
+//! When a connection is established, the process being controlled returns an
+//! interfaces::Init pointer to the controlling process, which the controlling
+//! process can use to get access to other interfaces and functionality.
+//!
+//! When spawning a new process, the steps are:
+//!
+//! 1. The controlling process calls interfaces::Ipc::spawnProcess(), which
+//!    calls ipc::Process::spawn(), which spawns a new process and returns a
+//!    socketpair file descriptor for communicating with it.
+//!    interfaces::Ipc::spawnProcess() then calls ipc::Protocol::connect()
+//!    passing the socketpair descriptor, which returns a local proxy
+//!    interfaces::Init implementation calling remote interfaces::Init methods.
+//! 2. The spawned process calls interfaces::Ipc::startSpawnProcess(), which
+//!    calls ipc::Process::checkSpawned() to read command line arguments and
+//!    determine whether it is a spawned process and what socketpair file
+//!    descriptor it should use. It then calls ipc::Protocol::serve() to handle
+//!    incoming requests from the socketpair and invoke interfaces::Init
+//!    interface methods, and exit when the socket is closed.
+//! 3. The controlling process calls local proxy interfaces::Init object methods
+//!    to make other proxy objects calling other remote interfaces. It can also
+//!    destroy the initial interfaces::Init object to close the connection and
+//!    shut down the spawned process.
+class Ipc
+{
+public:
+    virtual ~Ipc() = default;
+
+    //! Spawn a child process returning pointer to its Init interface.
+    virtual std::unique_ptr<Init> spawnProcess(const char* exe_name) = 0;
+
+    //! If this is a spawned process, block and handle requests from the parent
+    //! process by forwarding them to this process's Init interface, then return
+    //! true. If this is not a spawned child process, return false.
+    virtual bool startSpawnedProcess(int argc, char* argv[], int& exit_status) = 0;
+
+    //! Add cleanup callback to remote interface that will run when the
+    //! interface is deleted.
+    template<typename Interface>
+    void addCleanup(Interface& iface, std::function<void()> cleanup)
+    {
+        addCleanup(typeid(Interface), &iface, std::move(cleanup));
+    }
+
+protected:
+    //! Internal implementation of public addCleanup method (above) as a
+    //! type-erased virtual function, since template functions can't be virtual.
+    virtual void addCleanup(std::type_index type, void* iface, std::function<void()> cleanup) = 0;
+};
+
+//! Return implementation of Ipc interface.
+std::unique_ptr<Ipc> MakeIpc(const char* exe_name, const char* process_argv0, Init& init);
+} // namespace interfaces
+
+#endif // DIGIBYTE_INTERFACES_IPC_H

src/interfaces/node.h

@@ -0,0 +1,245 @@
+// Copyright (c) 2018-2020 The Bitcoin Core developers
+// Copyright (c) 2018-2020 The DigiByte Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef DIGIBYTE_INTERFACES_NODE_H
+#define DIGIBYTE_INTERFACES_NODE_H
+
+#include <amount.h>     // For CAmount
+#include <external_signer.h>
+#include <net.h>        // For NodeId
+#include <net_types.h>  // For banmap_t
+#include <netaddress.h> // For Network
+#include <netbase.h>    // For ConnectionDirection
+#include <support/allocators/secure.h> // For SecureString
+#include <util/translation.h>
+
+#include <functional>
+#include <memory>
+#include <stddef.h>
+#include <stdint.h>
+#include <string>
+#include <tuple>
+#include <vector>
+
+class BanMan;
+class CCoinControl;
+class CFeeRate;
+class CNodeStats;
+class Coin;
+class RPCTimerInterface;
+class UniValue;
+class proxyType;
+enum class SynchronizationState;
+struct CNodeStateStats;
+struct NodeContext;
+struct bilingual_str;
+
+namespace interfaces {
+class Handler;
+class WalletClient;
+struct BlockTip;
+
+//! Block and header tip information
+struct BlockAndHeaderTipInfo
+{
+    int block_height;
+    int64_t block_time;
+    int header_height;
+    int64_t header_time;
+    double verification_progress;
+};
+
+//! Top-level interface for a Vexta node (vextad process).
+class Node
+{
+public:
+    virtual ~Node() {}
+
+    //! Init logging.
+    virtual void initLogging() = 0;
+
+    //! Init parameter interaction.
+    virtual void initParameterInteraction() = 0;
+
+    //! Get warnings.
+    virtual bilingual_str getWarnings() = 0;
+
+    // Get log flags.
+    virtual uint32_t getLogCategories() = 0;
+
+    //! Initialize app dependencies.
+    virtual bool baseInitialize() = 0;
+
+    //! Start node.
+    virtual bool appInitMain(interfaces::BlockAndHeaderTipInfo* tip_info = nullptr) = 0;
+
+    //! Stop node.
+    virtual void appShutdown() = 0;
+
+    //! Start shutdown.
+    virtual void startShutdown() = 0;
+
+    //! Return whether shutdown was requested.
+    virtual bool shutdownRequested() = 0;
+
+    //! Map port.
+    virtual void mapPort(bool use_upnp, bool use_natpmp) = 0;
+
+    //! Get proxy.
+    virtual bool getProxy(Network net, proxyType& proxy_info) = 0;
+
+    //! Get number of connections.
+    virtual size_t getNodeCount(ConnectionDirection flags) = 0;
+
+    //! Get stats for connected nodes.
+    using NodesStats = std::vector<std::tuple<CNodeStats, bool, CNodeStateStats>>;
+    virtual bool getNodesStats(NodesStats& stats) = 0;
+
+    //! Get ban map entries.
+    virtual bool getBanned(banmap_t& banmap) = 0;
+
+    //! Ban node.
+    virtual bool ban(const CNetAddr& net_addr, int64_t ban_time_offset) = 0;
+
+    //! Unban node.
+    virtual bool unban(const CSubNet& ip) = 0;
+
+    //! Disconnect node by address.
+    virtual bool disconnectByAddress(const CNetAddr& net_addr) = 0;
+
+    //! Disconnect node by id.
+    virtual bool disconnectById(NodeId id) = 0;
+
+    //! List external signers
+    virtual std::vector<ExternalSigner> externalSigners() = 0;
+
+    //! Get total bytes recv.
+    virtual int64_t getTotalBytesRecv() = 0;
+
+    //! Get total bytes sent.
+    virtual int64_t getTotalBytesSent() = 0;
+
+    //! Get mempool size.
+    virtual size_t getMempoolSize() = 0;
+
+    //! Get mempool dynamic usage.
+    virtual size_t getMempoolDynamicUsage() = 0;
+
+    //! Get header tip height and time.
+    virtual bool getHeaderTip(int& height, int64_t& block_time) = 0;
+
+    //! Get num blocks.
+    virtual int getNumBlocks() = 0;
+
+    //! Get best block hash.
+    virtual uint256 getBestBlockHash() = 0;
+
+    //! Get last block time.
+    virtual int64_t getLastBlockTime() = 0;
+
+    //! Get verification progress.
+    virtual double getVerificationProgress() = 0;
+
+    //! Is initial block download.
+    virtual bool isInitialBlockDownload() = 0;
+
+    //! Get reindex.
+    virtual bool getReindex() = 0;
+
+    //! Get importing.
+    virtual bool getImporting() = 0;
+
+    //! Set network active.
+    virtual void setNetworkActive(bool active) = 0;
+
+    //! Get network active.
+    virtual bool getNetworkActive() = 0;
+
+    //! Get dust relay fee.
+    virtual CFeeRate getDustRelayFee() = 0;
+
+    //! Execute rpc command.
+    virtual UniValue executeRpc(const std::string& command, const UniValue& params, const std::string& uri) = 0;
+
+    //! List rpc commands.
+    virtual std::vector<std::string> listRpcCommands() = 0;
+
+    //! Set RPC timer interface if unset.
+    virtual void rpcSetTimerInterfaceIfUnset(RPCTimerInterface* iface) = 0;
+
+    //! Unset RPC timer interface.
+    virtual void rpcUnsetTimerInterface(RPCTimerInterface* iface) = 0;
+
+    //! Get unspent outputs associated with a transaction.
+    virtual bool getUnspentOutput(const COutPoint& output, Coin& coin) = 0;
+
+    //! Get wallet client.
+    virtual WalletClient& walletClient() = 0;
+
+    //! Register handler for init messages.
+    using InitMessageFn = std::function<void(const std::string& message)>;
+    virtual std::unique_ptr<Handler> handleInitMessage(InitMessageFn fn) = 0;
+
+    //! Register handler for message box messages.
+    using MessageBoxFn =
+        std::function<bool(const bilingual_str& message, const std::string& caption, unsigned int style)>;
+    virtual std::unique_ptr<Handler> handleMessageBox(MessageBoxFn fn) = 0;
+
+    //! Register handler for question messages.
+    using QuestionFn = std::function<bool(const bilingual_str& message,
+        const std::string& non_interactive_message,
+        const std::string& caption,
+        unsigned int style)>;
+    virtual std::unique_ptr<Handler> handleQuestion(QuestionFn fn) = 0;
+
+    //! Register handler for progress messages.
+    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 number of connections changed messages.
+    using NotifyNumConnectionsChangedFn = std::function<void(int new_num_connections)>;
+    virtual std::unique_ptr<Handler> handleNotifyNumConnectionsChanged(NotifyNumConnectionsChangedFn fn) = 0;
+
+    //! Register handler for network active messages.
+    using NotifyNetworkActiveChangedFn = std::function<void(bool network_active)>;
+    virtual std::unique_ptr<Handler> handleNotifyNetworkActiveChanged(NotifyNetworkActiveChangedFn fn) = 0;
+
+    //! Register handler for notify alert messages.
+    using NotifyAlertChangedFn = std::function<void()>;
+    virtual std::unique_ptr<Handler> handleNotifyAlertChanged(NotifyAlertChangedFn fn) = 0;
+
+    //! Register handler for ban list messages.
+    using BannedListChangedFn = std::function<void()>;
+    virtual std::unique_ptr<Handler> handleBannedListChanged(BannedListChangedFn fn) = 0;
+
+    //! Register handler for block tip messages.
+    using NotifyBlockTipFn =
+        std::function<void(SynchronizationState, interfaces::BlockTip tip, double verification_progress)>;
+    virtual std::unique_ptr<Handler> handleNotifyBlockTip(NotifyBlockTipFn fn) = 0;
+
+    //! Register handler for header tip messages.
+    using NotifyHeaderTipFn =
+        std::function<void(SynchronizationState, interfaces::BlockTip tip, double verification_progress)>;
+    virtual std::unique_ptr<Handler> handleNotifyHeaderTip(NotifyHeaderTipFn fn) = 0;
+
+    //! Get and set internal node context. Useful for testing, but not
+    //! accessible across processes.
+    virtual NodeContext* context() { return nullptr; }
+    virtual void setContext(NodeContext* context) { }
+};
+
+//! Return implementation of Node interface.
+std::unique_ptr<Node> MakeNode(NodeContext* context = nullptr);
+
+//! Block tip (could be a header or not, depends on the subscribed signal).
+struct BlockTip {
+    int block_height;
+    int64_t block_time;
+    uint256 block_hash;
+};
+
+} // namespace interfaces
+
+#endif // DIGIBYTE_INTERFACES_NODE_H

src/interfaces/wallet.h

@@ -0,0 +1,422 @@
+// Copyright (c) 2018-2020 The Bitcoin Core developers
+// Copyright (c) 2018-2020 The DigiByte Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef DIGIBYTE_INTERFACES_WALLET_H
+#define DIGIBYTE_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
+#include <util/message.h>
+#include <util/ui_change_type.h>
+
+#include <functional>
+#include <map>
+#include <memory>
+#include <stdint.h>
+#include <string>
+#include <tuple>
+#include <utility>
+#include <vector>
+
+class CCoinControl;
+class CFeeRate;
+class CKey;
+class CWallet;
+enum class FeeReason;
+enum class OutputType;
+enum class TransactionError;
+enum isminetype : unsigned int;
+struct CRecipient;
+struct PartiallySignedTransaction;
+struct WalletContext;
+struct bilingual_str;
+typedef uint8_t isminefilter;
+
+namespace interfaces {
+
+class Handler;
+struct WalletAddress;
+struct WalletBalances;
+struct WalletTx;
+struct WalletTxOut;
+struct WalletTxStatus;
+
+using WalletOrderForm = std::vector<std::pair<std::string, std::string>>;
+using WalletValueMap = std::map<std::string, std::string>;
+
+//! Interface for accessing a wallet.
+class Wallet
+{
+public:
+    virtual ~Wallet() {}
+
+    //! Encrypt wallet.
+    virtual bool encryptWallet(const SecureString& wallet_passphrase) = 0;
+
+    //! Return whether wallet is encrypted.
+    virtual bool isCrypted() = 0;
+
+    //! Lock wallet.
+    virtual bool lock() = 0;
+
+    //! Unlock wallet.
+    virtual bool unlock(const SecureString& wallet_passphrase) = 0;
+
+    //! Return whether wallet is locked.
+    virtual bool isLocked() = 0;
+
+    //! Change wallet passphrase.
+    virtual bool changeWalletPassphrase(const SecureString& old_wallet_passphrase,
+        const SecureString& new_wallet_passphrase) = 0;
+
+    //! Abort a rescan.
+    virtual void abortRescan() = 0;
+
+    //! Back up wallet.
+    virtual bool backupWallet(const std::string& filename) = 0;
+
+    //! Get wallet name.
+    virtual std::string getWalletName() = 0;
+
+    // Get a new address.
+    virtual bool getNewDestination(const OutputType type, const std::string label, CTxDestination& dest) = 0;
+
+    //! Get public key.
+    virtual bool getPubKey(const CScript& script, const CKeyID& address, CPubKey& pub_key) = 0;
+
+    //! Sign message
+    virtual SigningResult signMessage(const std::string& message, const PKHash& pkhash, std::string& str_sig) = 0;
+
+    //! Return whether wallet has private key.
+    virtual bool isSpendable(const CTxDestination& dest) = 0;
+
+    //! Return whether wallet has watch only keys.
+    virtual bool haveWatchOnly() = 0;
+
+    //! Add or update address.
+    virtual bool setAddressBook(const CTxDestination& dest, const std::string& name, const std::string& purpose) = 0;
+
+    // Remove address.
+    virtual bool delAddressBook(const CTxDestination& dest) = 0;
+
+    //! Look up address in wallet, return whether exists.
+    virtual bool getAddress(const CTxDestination& dest,
+        std::string* name,
+        isminetype* is_mine,
+        std::string* purpose) = 0;
+
+    //! Get wallet address list.
+    virtual std::vector<WalletAddress> getAddresses() = 0;
+
+    //! Get receive requests.
+    virtual std::vector<std::string> getAddressReceiveRequests() = 0;
+
+    //! Save or remove receive request.
+    virtual bool setAddressReceiveRequest(const CTxDestination& dest, const std::string& id, const std::string& value) = 0;
+
+    //! Display address on external signer
+    virtual bool displayAddress(const CTxDestination& dest) = 0;
+
+    //! Lock coin.
+    virtual void lockCoin(const COutPoint& output) = 0;
+
+    //! Unlock coin.
+    virtual void unlockCoin(const COutPoint& output) = 0;
+
+    //! Return whether coin is locked.
+    virtual bool isLockedCoin(const COutPoint& output) = 0;
+
+    //! List locked coins.
+    virtual void listLockedCoins(std::vector<COutPoint>& outputs) = 0;
+
+    //! Create transaction.
+    virtual CTransactionRef createTransaction(const std::vector<CRecipient>& recipients,
+        const CCoinControl& coin_control,
+        bool sign,
+        int& change_pos,
+        CAmount& fee,
+        bilingual_str& fail_reason) = 0;
+
+    //! Commit transaction.
+    virtual void commitTransaction(CTransactionRef tx,
+        WalletValueMap value_map,
+        WalletOrderForm order_form) = 0;
+
+    //! Return whether transaction can be abandoned.
+    virtual bool transactionCanBeAbandoned(const uint256& txid) = 0;
+
+    //! Abandon transaction.
+    virtual bool abandonTransaction(const uint256& txid) = 0;
+
+    //! Return whether transaction can be bumped.
+    virtual bool transactionCanBeBumped(const uint256& txid) = 0;
+
+    //! Create bump transaction.
+    virtual bool createBumpTransaction(const uint256& txid,
+        const CCoinControl& coin_control,
+        std::vector<bilingual_str>& errors,
+        CAmount& old_fee,
+        CAmount& new_fee,
+        CMutableTransaction& mtx) = 0;
+
+    //! Sign bump transaction.
+    virtual bool signBumpTransaction(CMutableTransaction& mtx) = 0;
+
+    //! Commit bump transaction.
+    virtual bool commitBumpTransaction(const uint256& txid,
+        CMutableTransaction&& mtx,
+        std::vector<bilingual_str>& errors,
+        uint256& bumped_txid) = 0;
+
+    //! Get a transaction.
+    virtual CTransactionRef getTx(const uint256& txid) = 0;
+
+    //! Get transaction information.
+    virtual WalletTx getWalletTx(const uint256& txid) = 0;
+
+    //! Get list of all wallet transactions.
+    virtual std::vector<WalletTx> getWalletTxs() = 0;
+
+    //! Try to get updated status for a particular transaction, if possible without blocking.
+    virtual bool tryGetTxStatus(const uint256& txid,
+        WalletTxStatus& tx_status,
+        int& num_blocks,
+        int64_t& block_time) = 0;
+
+    //! Get transaction details.
+    virtual WalletTx getWalletTxDetails(const uint256& txid,
+        WalletTxStatus& tx_status,
+        WalletOrderForm& order_form,
+        bool& in_mempool,
+        int& num_blocks) = 0;
+
+    //! Fill PSBT.
+    virtual TransactionError fillPSBT(int sighash_type,
+        bool sign,
+        bool bip32derivs,
+        size_t* n_signed,
+        PartiallySignedTransaction& psbtx,
+        bool& complete) = 0;
+
+    //! Get balances.
+    virtual WalletBalances getBalances() = 0;
+
+    //! Get balances if possible without blocking.
+    virtual bool tryGetBalances(WalletBalances& balances, uint256& block_hash) = 0;
+
+    //! Get balance.
+    virtual CAmount getBalance() = 0;
+
+    //! Get available balance.
+    virtual CAmount getAvailableBalance(const CCoinControl& coin_control) = 0;
+
+    //! Return whether transaction input belongs to wallet.
+    virtual isminetype txinIsMine(const CTxIn& txin) = 0;
+
+    //! Return whether transaction output belongs to wallet.
+    virtual isminetype txoutIsMine(const CTxOut& txout) = 0;
+
+    //! Return debit amount if transaction input belongs to wallet.
+    virtual CAmount getDebit(const CTxIn& txin, isminefilter filter) = 0;
+
+    //! Return credit amount if transaction input belongs to wallet.
+    virtual CAmount getCredit(const CTxOut& txout, isminefilter filter) = 0;
+
+    //! Return AvailableCoins + LockedCoins grouped by wallet address.
+    //! (put change in one group with wallet address)
+    using CoinsList = std::map<CTxDestination, std::vector<std::tuple<COutPoint, WalletTxOut>>>;
+    virtual CoinsList listCoins() = 0;
+
+    //! Return wallet transaction output information.
+    virtual std::vector<WalletTxOut> getCoins(const std::vector<COutPoint>& outputs) = 0;
+
+    //! Get required fee.
+    virtual CAmount getRequiredFee(unsigned int tx_bytes) = 0;
+
+    //! Get minimum fee.
+    virtual CAmount getMinimumFee(unsigned int tx_bytes,
+        const CCoinControl& coin_control,
+        int* returned_target,
+        FeeReason* reason) = 0;
+
+    //! Get tx confirm target.
+    virtual unsigned int getConfirmTarget() = 0;
+
+    // Return whether HD enabled.
+    virtual bool hdEnabled() = 0;
+
+    // Return whether the wallet is blank.
+    virtual bool canGetAddresses() = 0;
+
+    // Return whether private keys enabled.
+    virtual bool privateKeysDisabled() = 0;
+
+    // Return whether wallet uses an external signer.
+    virtual bool hasExternalSigner() = 0;
+
+    // Get default address type.
+    virtual OutputType getDefaultAddressType() = 0;
+
+    //! Get max tx fee.
+    virtual CAmount getDefaultMaxTxFee() = 0;
+
+    // Remove wallet.
+    virtual void remove() = 0;
+
+    //! Return whether is a legacy wallet
+    virtual bool isLegacy() = 0;
+
+    //! Register handler for unload message.
+    using UnloadFn = std::function<void()>;
+    virtual std::unique_ptr<Handler> handleUnload(UnloadFn fn) = 0;
+
+    //! Register handler for show progress messages.
+    using ShowProgressFn = std::function<void(const std::string& title, int progress)>;
+    virtual std::unique_ptr<Handler> handleShowProgress(ShowProgressFn fn) = 0;
+
+    //! Register handler for status changed messages.
+    using StatusChangedFn = std::function<void()>;
+    virtual std::unique_ptr<Handler> handleStatusChanged(StatusChangedFn fn) = 0;
+
+    //! Register handler for address book changed messages.
+    using AddressBookChangedFn = std::function<void(const CTxDestination& address,
+        const std::string& label,
+        bool is_mine,
+        const std::string& purpose,
+        ChangeType status)>;
+    virtual std::unique_ptr<Handler> handleAddressBookChanged(AddressBookChangedFn fn) = 0;
+
+    //! Register handler for transaction changed messages.
+    using TransactionChangedFn = std::function<void(const uint256& txid, ChangeType status)>;
+    virtual std::unique_ptr<Handler> handleTransactionChanged(TransactionChangedFn fn) = 0;
+
+    //! Register handler for watchonly changed messages.
+    using WatchOnlyChangedFn = std::function<void(bool have_watch_only)>;
+    virtual std::unique_ptr<Handler> handleWatchOnlyChanged(WatchOnlyChangedFn fn) = 0;
+
+    //! Register handler for keypool changed messages.
+    using CanGetAddressesChangedFn = std::function<void()>;
+    virtual std::unique_ptr<Handler> handleCanGetAddressesChanged(CanGetAddressesChangedFn fn) = 0;
+
+    //! Return pointer to internal wallet class, useful for testing.
+    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, 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
+{
+    CTxDestination dest;
+    isminetype is_mine;
+    std::string name;
+    std::string purpose;
+
+    WalletAddress(CTxDestination dest, isminetype is_mine, std::string name, std::string purpose)
+        : dest(std::move(dest)), is_mine(is_mine), name(std::move(name)), purpose(std::move(purpose))
+    {
+    }
+};
+
+//! Collection of wallet balances.
+struct WalletBalances
+{
+    CAmount balance = 0;
+    CAmount unconfirmed_balance = 0;
+    CAmount immature_balance = 0;
+    bool have_watch_only = false;
+    CAmount watch_only_balance = 0;
+    CAmount unconfirmed_watch_only_balance = 0;
+    CAmount immature_watch_only_balance = 0;
+
+    bool balanceChanged(const WalletBalances& prev) const
+    {
+        return balance != prev.balance || unconfirmed_balance != prev.unconfirmed_balance ||
+               immature_balance != prev.immature_balance || watch_only_balance != prev.watch_only_balance ||
+               unconfirmed_watch_only_balance != prev.unconfirmed_watch_only_balance ||
+               immature_watch_only_balance != prev.immature_watch_only_balance;
+    }
+};
+
+// Wallet transaction information.
+struct WalletTx
+{
+    CTransactionRef tx;
+    std::vector<isminetype> txin_is_mine;
+    std::vector<isminetype> txout_is_mine;
+    std::vector<CTxDestination> txout_address;
+    std::vector<isminetype> txout_address_is_mine;
+    CAmount credit;
+    CAmount debit;
+    CAmount change;
+    int64_t time;
+    std::map<std::string, std::string> value_map;
+    bool is_coinbase;
+};
+
+//! Updated transaction status.
+struct WalletTxStatus
+{
+    int block_height;
+    int blocks_to_maturity;
+    int depth_in_main_chain;
+    unsigned int time_received;
+    uint32_t lock_time;
+    bool is_final;
+    bool is_trusted;
+    bool is_abandoned;
+    bool is_coinbase;
+    bool is_in_main_chain;
+};
+
+//! Wallet transaction output.
+struct WalletTxOut
+{
+    CTxOut txout;
+    int64_t time;
+    int depth_in_main_chain = -1;
+    bool is_spent = false;
+};
+
+//! Return implementation of Wallet interface. This function is defined in
+//! 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);
+
+} // namespace interfaces
+
+#endif // DIGIBYTE_INTERFACES_WALLET_H