Merge #20494: refactor: Move node and wallet code out of src/interfaces

629a9299b2a7241a3fa7d597cb34abcbe1af9255 Move WalletImpl from interfaces/wallet.cpp to wallet/interfaces.cpp (Russell Yanofsky)
2a26771d8161d30be1853a35acfee588cce03634 Move ChainImpl from interfaces/chain.cpp to node/interfaces.cpp (Russell Yanofsky)
12bd0fc9d70333c54c83ebb08c734272dbd330c2 Move NodeImpl from interfaces/node.cpp to node/interfaces.cpp (Russell Yanofsky)

Pull request description:

  This PR is part of the [process separation project](https://github.com/bitcoin/bitcoin/projects/10).

  ---

  Move `NodeImpl` from `interfaces/node.cpp` to `node/interfaces.cpp`
  Move `ChainImpl` from `interfaces/chain.cpp` to `node/interfaces.cpp`
  Move `WalletImpl` from `interfaces/wallet.cpp` to `wallet/interfaces.cpp`

  No changes to any classes (can review with `git diff --color-moved=dimmed_zebra`)

  Motivation for this change is to move node and wallet code to respective directories where it might fit in better than `src/interfaces/`, but also to remove all unnecessary code from `src/interfaces/` to unblock #19160 review, which has been hung up partially because of code organization. Building on top of this PR, #19160 should now be able to organize interface implementations more understandably in `src/node/` `src/wallet/` `src/ipc/` and `src/init/` directories instead of having so much functionality all in `src/interfaces/`

ACKs for top commit:
  promag:
    Code review ACK 629a9299b2a7241a3fa7d597cb34abcbe1af9255.
  MarcoFalke:
    review ACK 629a9299b2a7241a3fa7d597cb34abcbe1af9255 🔺

Tree-SHA512: 87c2b8fd51519bbd4e5ad3539a79debcf88c3bf021eb28c63f3f555186538b62a0c4cc1a3f07cfb4ff13aea8b0b2fdde505d81f22a5e5fd12a6e375b55a92ab8

1 files changed, 693 insertions, 0 deletions

diff --git a/src/node/interfaces.cpp b/src/node/interfaces.cpp
new file mode 100644
index 0000000000..77a5957a56
--- /dev/null
+++ b/src/node/interfaces.cpp
@@ -0,0 +1,693 @@
+// Copyright (c) 2018-2020 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <addrdb.h>
+#include <banman.h>
+#include <boost/signals2/signal.hpp>
+#include <chain.h>
+#include <chainparams.h>
+#include <init.h>
+#include <interfaces/chain.h>
+#include <interfaces/handler.h>
+#include <interfaces/node.h>
+#include <interfaces/wallet.h>
+#include <net.h>
+#include <net_processing.h>
+#include <netaddress.h>
+#include <netbase.h>
+#include <node/coin.h>
+#include <node/context.h>
+#include <node/transaction.h>
+#include <node/ui_interface.h>
+#include <policy/feerate.h>
+#include <policy/fees.h>
+#include <policy/policy.h>
+#include <policy/rbf.h>
+#include <policy/settings.h>
+#include <primitives/block.h>
+#include <primitives/transaction.h>
+#include <rpc/protocol.h>
+#include <rpc/server.h>
+#include <shutdown.h>
+#include <support/allocators/secure.h>
+#include <sync.h>
+#include <timedata.h>
+#include <txmempool.h>
+#include <uint256.h>
+#include <univalue.h>
+#include <util/check.h>
+#include <util/ref.h>
+#include <util/system.h>
+#include <util/translation.h>
+#include <validation.h>
+#include <validationinterface.h>
+#include <warnings.h>
+
+#if defined(HAVE_CONFIG_H)
+#include <config/bitcoin-config.h>
+#endif
+
+#include <memory>
+#include <utility>
+
+using interfaces::BlockTip;
+using interfaces::Chain;
+using interfaces::FoundBlock;
+using interfaces::Handler;
+using interfaces::MakeHandler;
+using interfaces::Node;
+using interfaces::WalletClient;
+
+namespace node {
+namespace {
+class NodeImpl : public Node
+{
+public:
+    NodeImpl(NodeContext* context) { setContext(context); }
+    void initLogging() override { InitLogging(*Assert(m_context->args)); }
+    void initParameterInteraction() override { InitParameterInteraction(*Assert(m_context->args)); }
+    bilingual_str getWarnings() override { return GetWarnings(true); }
+    uint32_t getLogCategories() override { return LogInstance().GetCategoryMask(); }
+    bool baseInitialize() override
+    {
+        return AppInitBasicSetup(gArgs) && AppInitParameterInteraction(gArgs) && AppInitSanityChecks() &&
+               AppInitLockDataDirectory() && AppInitInterfaces(*m_context);
+    }
+    bool appInitMain(interfaces::BlockAndHeaderTipInfo* tip_info) override
+    {
+        return AppInitMain(m_context_ref, *m_context, tip_info);
+    }
+    void appShutdown() override
+    {
+        Interrupt(*m_context);
+        Shutdown(*m_context);
+    }
+    void startShutdown() override
+    {
+        StartShutdown();
+        // Stop RPC for clean shutdown if any of waitfor* commands is executed.
+        if (gArgs.GetBoolArg("-server", false)) {
+            InterruptRPC();
+            StopRPC();
+        }
+    }
+    bool shutdownRequested() override { return ShutdownRequested(); }
+    void mapPort(bool use_upnp) override
+    {
+        if (use_upnp) {
+            StartMapPort();
+        } else {
+            InterruptMapPort();
+            StopMapPort();
+        }
+    }
+    bool getProxy(Network net, proxyType& proxy_info) override { return GetProxy(net, proxy_info); }
+    size_t getNodeCount(CConnman::NumConnections flags) override
+    {
+        return m_context->connman ? m_context->connman->GetNodeCount(flags) : 0;
+    }
+    bool getNodesStats(NodesStats& stats) override
+    {
+        stats.clear();
+
+        if (m_context->connman) {
+            std::vector<CNodeStats> stats_temp;
+            m_context->connman->GetNodeStats(stats_temp);
+
+            stats.reserve(stats_temp.size());
+            for (auto& node_stats_temp : stats_temp) {
+                stats.emplace_back(std::move(node_stats_temp), false, CNodeStateStats());
+            }
+
+            // Try to retrieve the CNodeStateStats for each node.
+            TRY_LOCK(::cs_main, lockMain);
+            if (lockMain) {
+                for (auto& node_stats : stats) {
+                    std::get<1>(node_stats) =
+                        GetNodeStateStats(std::get<0>(node_stats).nodeid, std::get<2>(node_stats));
+                }
+            }
+            return true;
+        }
+        return false;
+    }
+    bool getBanned(banmap_t& banmap) override
+    {
+        if (m_context->banman) {
+            m_context->banman->GetBanned(banmap);
+            return true;
+        }
+        return false;
+    }
+    bool ban(const CNetAddr& net_addr, int64_t ban_time_offset) override
+    {
+        if (m_context->banman) {
+            m_context->banman->Ban(net_addr, ban_time_offset);
+            return true;
+        }
+        return false;
+    }
+    bool unban(const CSubNet& ip) override
+    {
+        if (m_context->banman) {
+            m_context->banman->Unban(ip);
+            return true;
+        }
+        return false;
+    }
+    bool disconnectByAddress(const CNetAddr& net_addr) override
+    {
+        if (m_context->connman) {
+            return m_context->connman->DisconnectNode(net_addr);
+        }
+        return false;
+    }
+    bool disconnectById(NodeId id) override
+    {
+        if (m_context->connman) {
+            return m_context->connman->DisconnectNode(id);
+        }
+        return false;
+    }
+    int64_t getTotalBytesRecv() override { return m_context->connman ? m_context->connman->GetTotalBytesRecv() : 0; }
+    int64_t getTotalBytesSent() override { return m_context->connman ? m_context->connman->GetTotalBytesSent() : 0; }
+    size_t getMempoolSize() override { return m_context->mempool ? m_context->mempool->size() : 0; }
+    size_t getMempoolDynamicUsage() override { return m_context->mempool ? m_context->mempool->DynamicMemoryUsage() : 0; }
+    bool getHeaderTip(int& height, int64_t& block_time) override
+    {
+        LOCK(::cs_main);
+        if (::pindexBestHeader) {
+            height = ::pindexBestHeader->nHeight;
+            block_time = ::pindexBestHeader->GetBlockTime();
+            return true;
+        }
+        return false;
+    }
+    int getNumBlocks() override
+    {
+        LOCK(::cs_main);
+        return ::ChainActive().Height();
+    }
+    uint256 getBestBlockHash() override
+    {
+        const CBlockIndex* tip = WITH_LOCK(::cs_main, return ::ChainActive().Tip());
+        return tip ? tip->GetBlockHash() : Params().GenesisBlock().GetHash();
+    }
+    int64_t getLastBlockTime() override
+    {
+        LOCK(::cs_main);
+        if (::ChainActive().Tip()) {
+            return ::ChainActive().Tip()->GetBlockTime();
+        }
+        return Params().GenesisBlock().GetBlockTime(); // Genesis block's time of current network
+    }
+    double getVerificationProgress() override
+    {
+        const CBlockIndex* tip;
+        {
+            LOCK(::cs_main);
+            tip = ::ChainActive().Tip();
+        }
+        return GuessVerificationProgress(Params().TxData(), tip);
+    }
+    bool isInitialBlockDownload() override { return ::ChainstateActive().IsInitialBlockDownload(); }
+    bool getReindex() override { return ::fReindex; }
+    bool getImporting() override { return ::fImporting; }
+    void setNetworkActive(bool active) override
+    {
+        if (m_context->connman) {
+            m_context->connman->SetNetworkActive(active);
+        }
+    }
+    bool getNetworkActive() override { return m_context->connman && m_context->connman->GetNetworkActive(); }
+    CFeeRate estimateSmartFee(int num_blocks, bool conservative, int* returned_target = nullptr) override
+    {
+        FeeCalculation fee_calc;
+        CFeeRate result = ::feeEstimator.estimateSmartFee(num_blocks, &fee_calc, conservative);
+        if (returned_target) {
+            *returned_target = fee_calc.returnedTarget;
+        }
+        return result;
+    }
+    CFeeRate getDustRelayFee() override { return ::dustRelayFee; }
+    UniValue executeRpc(const std::string& command, const UniValue& params, const std::string& uri) override
+    {
+        JSONRPCRequest req(m_context_ref);
+        req.params = params;
+        req.strMethod = command;
+        req.URI = uri;
+        return ::tableRPC.execute(req);
+    }
+    std::vector<std::string> listRpcCommands() override { return ::tableRPC.listCommands(); }
+    void rpcSetTimerInterfaceIfUnset(RPCTimerInterface* iface) override { RPCSetTimerInterfaceIfUnset(iface); }
+    void rpcUnsetTimerInterface(RPCTimerInterface* iface) override { RPCUnsetTimerInterface(iface); }
+    bool getUnspentOutput(const COutPoint& output, Coin& coin) override
+    {
+        LOCK(::cs_main);
+        return ::ChainstateActive().CoinsTip().GetCoin(output, coin);
+    }
+    WalletClient& walletClient() override
+    {
+        return *Assert(m_context->wallet_client);
+    }
+    std::unique_ptr<Handler> handleInitMessage(InitMessageFn fn) override
+    {
+        return MakeHandler(::uiInterface.InitMessage_connect(fn));
+    }
+    std::unique_ptr<Handler> handleMessageBox(MessageBoxFn fn) override
+    {
+        return MakeHandler(::uiInterface.ThreadSafeMessageBox_connect(fn));
+    }
+    std::unique_ptr<Handler> handleQuestion(QuestionFn fn) override
+    {
+        return MakeHandler(::uiInterface.ThreadSafeQuestion_connect(fn));
+    }
+    std::unique_ptr<Handler> handleShowProgress(ShowProgressFn fn) override
+    {
+        return MakeHandler(::uiInterface.ShowProgress_connect(fn));
+    }
+    std::unique_ptr<Handler> handleNotifyNumConnectionsChanged(NotifyNumConnectionsChangedFn fn) override
+    {
+        return MakeHandler(::uiInterface.NotifyNumConnectionsChanged_connect(fn));
+    }
+    std::unique_ptr<Handler> handleNotifyNetworkActiveChanged(NotifyNetworkActiveChangedFn fn) override
+    {
+        return MakeHandler(::uiInterface.NotifyNetworkActiveChanged_connect(fn));
+    }
+    std::unique_ptr<Handler> handleNotifyAlertChanged(NotifyAlertChangedFn fn) override
+    {
+        return MakeHandler(::uiInterface.NotifyAlertChanged_connect(fn));
+    }
+    std::unique_ptr<Handler> handleBannedListChanged(BannedListChangedFn fn) override
+    {
+        return MakeHandler(::uiInterface.BannedListChanged_connect(fn));
+    }
+    std::unique_ptr<Handler> handleNotifyBlockTip(NotifyBlockTipFn fn) override
+    {
+        return MakeHandler(::uiInterface.NotifyBlockTip_connect([fn](SynchronizationState sync_state, const CBlockIndex* block) {
+            fn(sync_state, BlockTip{block->nHeight, block->GetBlockTime(), block->GetBlockHash()},
+                GuessVerificationProgress(Params().TxData(), block));
+        }));
+    }
+    std::unique_ptr<Handler> handleNotifyHeaderTip(NotifyHeaderTipFn fn) override
+    {
+        return MakeHandler(
+            ::uiInterface.NotifyHeaderTip_connect([fn](SynchronizationState sync_state, const CBlockIndex* block) {
+                fn(sync_state, BlockTip{block->nHeight, block->GetBlockTime(), block->GetBlockHash()},
+                    /* verification progress is unused when a header was received */ 0);
+            }));
+    }
+    NodeContext* context() override { return m_context; }
+    void setContext(NodeContext* context) override
+    {
+        m_context = context;
+        if (context) {
+            m_context_ref.Set(*context);
+        } else {
+            m_context_ref.Clear();
+        }
+    }
+    NodeContext* m_context{nullptr};
+    util::Ref m_context_ref;
+};
+
+bool FillBlock(const CBlockIndex* index, const FoundBlock& block, UniqueLock<RecursiveMutex>& lock)
+{
+    if (!index) return false;
+    if (block.m_hash) *block.m_hash = index->GetBlockHash();
+    if (block.m_height) *block.m_height = index->nHeight;
+    if (block.m_time) *block.m_time = index->GetBlockTime();
+    if (block.m_max_time) *block.m_max_time = index->GetBlockTimeMax();
+    if (block.m_mtp_time) *block.m_mtp_time = index->GetMedianTimePast();
+    if (block.m_data) {
+        REVERSE_LOCK(lock);
+        if (!ReadBlockFromDisk(*block.m_data, index, Params().GetConsensus())) block.m_data->SetNull();
+    }
+    return true;
+}
+
+class NotificationsProxy : public CValidationInterface
+{
+public:
+    explicit NotificationsProxy(std::shared_ptr<Chain::Notifications> notifications)
+        : m_notifications(std::move(notifications)) {}
+    virtual ~NotificationsProxy() = default;
+    void TransactionAddedToMempool(const CTransactionRef& tx, uint64_t mempool_sequence) override
+    {
+        m_notifications->transactionAddedToMempool(tx, mempool_sequence);
+    }
+    void TransactionRemovedFromMempool(const CTransactionRef& tx, MemPoolRemovalReason reason, uint64_t mempool_sequence) override
+    {
+        m_notifications->transactionRemovedFromMempool(tx, reason, mempool_sequence);
+    }
+    void BlockConnected(const std::shared_ptr<const CBlock>& block, const CBlockIndex* index) override
+    {
+        m_notifications->blockConnected(*block, index->nHeight);
+    }
+    void BlockDisconnected(const std::shared_ptr<const CBlock>& block, const CBlockIndex* index) override
+    {
+        m_notifications->blockDisconnected(*block, index->nHeight);
+    }
+    void UpdatedBlockTip(const CBlockIndex* index, const CBlockIndex* fork_index, bool is_ibd) override
+    {
+        m_notifications->updatedBlockTip();
+    }
+    void ChainStateFlushed(const CBlockLocator& locator) override { m_notifications->chainStateFlushed(locator); }
+    std::shared_ptr<Chain::Notifications> m_notifications;
+};
+
+class NotificationsHandlerImpl : public Handler
+{
+public:
+    explicit NotificationsHandlerImpl(std::shared_ptr<Chain::Notifications> notifications)
+        : m_proxy(std::make_shared<NotificationsProxy>(std::move(notifications)))
+    {
+        RegisterSharedValidationInterface(m_proxy);
+    }
+    ~NotificationsHandlerImpl() override { disconnect(); }
+    void disconnect() override
+    {
+        if (m_proxy) {
+            UnregisterSharedValidationInterface(m_proxy);
+            m_proxy.reset();
+        }
+    }
+    std::shared_ptr<NotificationsProxy> m_proxy;
+};
+
+class RpcHandlerImpl : public Handler
+{
+public:
+    explicit RpcHandlerImpl(const CRPCCommand& command) : m_command(command), m_wrapped_command(&command)
+    {
+        m_command.actor = [this](const JSONRPCRequest& request, UniValue& result, bool last_handler) {
+            if (!m_wrapped_command) return false;
+            try {
+                return m_wrapped_command->actor(request, result, last_handler);
+            } catch (const UniValue& e) {
+                // If this is not the last handler and a wallet not found
+                // exception was thrown, return false so the next handler can
+                // try to handle the request. Otherwise, reraise the exception.
+                if (!last_handler) {
+                    const UniValue& code = e["code"];
+                    if (code.isNum() && code.get_int() == RPC_WALLET_NOT_FOUND) {
+                        return false;
+                    }
+                }
+                throw;
+            }
+        };
+        ::tableRPC.appendCommand(m_command.name, &m_command);
+    }
+
+    void disconnect() final
+    {
+        if (m_wrapped_command) {
+            m_wrapped_command = nullptr;
+            ::tableRPC.removeCommand(m_command.name, &m_command);
+        }
+    }
+
+    ~RpcHandlerImpl() override { disconnect(); }
+
+    CRPCCommand m_command;
+    const CRPCCommand* m_wrapped_command;
+};
+
+class ChainImpl : public Chain
+{
+public:
+    explicit ChainImpl(NodeContext& node) : m_node(node) {}
+    Optional<int> getHeight() override
+    {
+        LOCK(::cs_main);
+        int height = ::ChainActive().Height();
+        if (height >= 0) {
+            return height;
+        }
+        return nullopt;
+    }
+    Optional<int> getBlockHeight(const uint256& hash) override
+    {
+        LOCK(::cs_main);
+        CBlockIndex* block = LookupBlockIndex(hash);
+        if (block && ::ChainActive().Contains(block)) {
+            return block->nHeight;
+        }
+        return nullopt;
+    }
+    uint256 getBlockHash(int height) override
+    {
+        LOCK(::cs_main);
+        CBlockIndex* block = ::ChainActive()[height];
+        assert(block);
+        return block->GetBlockHash();
+    }
+    bool haveBlockOnDisk(int height) override
+    {
+        LOCK(cs_main);
+        CBlockIndex* block = ::ChainActive()[height];
+        return block && ((block->nStatus & BLOCK_HAVE_DATA) != 0) && block->nTx > 0;
+    }
+    Optional<int> findFirstBlockWithTimeAndHeight(int64_t time, int height, uint256* hash) override
+    {
+        LOCK(cs_main);
+        CBlockIndex* block = ::ChainActive().FindEarliestAtLeast(time, height);
+        if (block) {
+            if (hash) *hash = block->GetBlockHash();
+            return block->nHeight;
+        }
+        return nullopt;
+    }
+    CBlockLocator getTipLocator() override
+    {
+        LOCK(cs_main);
+        return ::ChainActive().GetLocator();
+    }
+    bool checkFinalTx(const CTransaction& tx) override
+    {
+        LOCK(cs_main);
+        return CheckFinalTx(tx);
+    }
+    Optional<int> findLocatorFork(const CBlockLocator& locator) override
+    {
+        LOCK(cs_main);
+        if (CBlockIndex* fork = FindForkInGlobalIndex(::ChainActive(), locator)) {
+            return fork->nHeight;
+        }
+        return nullopt;
+    }
+    bool findBlock(const uint256& hash, const FoundBlock& block) override
+    {
+        WAIT_LOCK(cs_main, lock);
+        return FillBlock(LookupBlockIndex(hash), block, lock);
+    }
+    bool findFirstBlockWithTimeAndHeight(int64_t min_time, int min_height, const FoundBlock& block) override
+    {
+        WAIT_LOCK(cs_main, lock);
+        return FillBlock(ChainActive().FindEarliestAtLeast(min_time, min_height), block, lock);
+    }
+    bool findNextBlock(const uint256& block_hash, int block_height, const FoundBlock& next, bool* reorg) override {
+        WAIT_LOCK(cs_main, lock);
+        CBlockIndex* block = ChainActive()[block_height];
+        if (block && block->GetBlockHash() != block_hash) block = nullptr;
+        if (reorg) *reorg = !block;
+        return FillBlock(block ? ChainActive()[block_height + 1] : nullptr, next, lock);
+    }
+    bool findAncestorByHeight(const uint256& block_hash, int ancestor_height, const FoundBlock& ancestor_out) override
+    {
+        WAIT_LOCK(cs_main, lock);
+        if (const CBlockIndex* block = LookupBlockIndex(block_hash)) {
+            if (const CBlockIndex* ancestor = block->GetAncestor(ancestor_height)) {
+                return FillBlock(ancestor, ancestor_out, lock);
+            }
+        }
+        return FillBlock(nullptr, ancestor_out, lock);
+    }
+    bool findAncestorByHash(const uint256& block_hash, const uint256& ancestor_hash, const FoundBlock& ancestor_out) override
+    {
+        WAIT_LOCK(cs_main, lock);
+        const CBlockIndex* block = LookupBlockIndex(block_hash);
+        const CBlockIndex* ancestor = LookupBlockIndex(ancestor_hash);
+        if (block && ancestor && block->GetAncestor(ancestor->nHeight) != ancestor) ancestor = nullptr;
+        return FillBlock(ancestor, ancestor_out, lock);
+    }
+    bool findCommonAncestor(const uint256& block_hash1, const uint256& block_hash2, const FoundBlock& ancestor_out, const FoundBlock& block1_out, const FoundBlock& block2_out) override
+    {
+        WAIT_LOCK(cs_main, lock);
+        const CBlockIndex* block1 = LookupBlockIndex(block_hash1);
+        const CBlockIndex* block2 = LookupBlockIndex(block_hash2);
+        const CBlockIndex* ancestor = block1 && block2 ? LastCommonAncestor(block1, block2) : nullptr;
+        // Using & instead of && below to avoid short circuiting and leaving
+        // output uninitialized.
+        return FillBlock(ancestor, ancestor_out, lock) & FillBlock(block1, block1_out, lock) & FillBlock(block2, block2_out, lock);
+    }
+    void findCoins(std::map<COutPoint, Coin>& coins) override { return FindCoins(m_node, coins); }
+    double guessVerificationProgress(const uint256& block_hash) override
+    {
+        LOCK(cs_main);
+        return GuessVerificationProgress(Params().TxData(), LookupBlockIndex(block_hash));
+    }
+    bool hasBlocks(const uint256& block_hash, int min_height, Optional<int> max_height) override
+    {
+        // hasBlocks returns true if all ancestors of block_hash in specified
+        // range have block data (are not pruned), false if any ancestors in
+        // specified range are missing data.
+        //
+        // For simplicity and robustness, min_height and max_height are only
+        // used to limit the range, and passing min_height that's too low or
+        // max_height that's too high will not crash or change the result.
+        LOCK(::cs_main);
+        if (CBlockIndex* block = LookupBlockIndex(block_hash)) {
+            if (max_height && block->nHeight >= *max_height) block = block->GetAncestor(*max_height);
+            for (; block->nStatus & BLOCK_HAVE_DATA; block = block->pprev) {
+                // Check pprev to not segfault if min_height is too low
+                if (block->nHeight <= min_height || !block->pprev) return true;
+            }
+        }
+        return false;
+    }
+    RBFTransactionState isRBFOptIn(const CTransaction& tx) override
+    {
+        if (!m_node.mempool) return IsRBFOptInEmptyMempool(tx);
+        LOCK(m_node.mempool->cs);
+        return IsRBFOptIn(tx, *m_node.mempool);
+    }
+    bool hasDescendantsInMempool(const uint256& txid) override
+    {
+        if (!m_node.mempool) return false;
+        LOCK(m_node.mempool->cs);
+        auto it = m_node.mempool->GetIter(txid);
+        return it && (*it)->GetCountWithDescendants() > 1;
+    }
+    bool broadcastTransaction(const CTransactionRef& tx,
+        const CAmount& max_tx_fee,
+        bool relay,
+        std::string& err_string) override
+    {
+        const TransactionError err = BroadcastTransaction(m_node, tx, err_string, max_tx_fee, relay, /*wait_callback*/ false);
+        // Chain clients only care about failures to accept the tx to the mempool. Disregard non-mempool related failures.
+        // Note: this will need to be updated if BroadcastTransactions() is updated to return other non-mempool failures
+        // that Chain clients do not need to know about.
+        return TransactionError::OK == err;
+    }
+    void getTransactionAncestry(const uint256& txid, size_t& ancestors, size_t& descendants) override
+    {
+        ancestors = descendants = 0;
+        if (!m_node.mempool) return;
+        m_node.mempool->GetTransactionAncestry(txid, ancestors, descendants);
+    }
+    void getPackageLimits(unsigned int& limit_ancestor_count, unsigned int& limit_descendant_count) override
+    {
+        limit_ancestor_count = gArgs.GetArg("-limitancestorcount", DEFAULT_ANCESTOR_LIMIT);
+        limit_descendant_count = gArgs.GetArg("-limitdescendantcount", DEFAULT_DESCENDANT_LIMIT);
+    }
+    bool checkChainLimits(const CTransactionRef& tx) override
+    {
+        if (!m_node.mempool) return true;
+        LockPoints lp;
+        CTxMemPoolEntry entry(tx, 0, 0, 0, false, 0, lp);
+        CTxMemPool::setEntries ancestors;
+        auto limit_ancestor_count = gArgs.GetArg("-limitancestorcount", DEFAULT_ANCESTOR_LIMIT);
+        auto limit_ancestor_size = gArgs.GetArg("-limitancestorsize", DEFAULT_ANCESTOR_SIZE_LIMIT) * 1000;
+        auto limit_descendant_count = gArgs.GetArg("-limitdescendantcount", DEFAULT_DESCENDANT_LIMIT);
+        auto limit_descendant_size = gArgs.GetArg("-limitdescendantsize", DEFAULT_DESCENDANT_SIZE_LIMIT) * 1000;
+        std::string unused_error_string;
+        LOCK(m_node.mempool->cs);
+        return m_node.mempool->CalculateMemPoolAncestors(
+            entry, ancestors, limit_ancestor_count, limit_ancestor_size,
+            limit_descendant_count, limit_descendant_size, unused_error_string);
+    }
+    CFeeRate estimateSmartFee(int num_blocks, bool conservative, FeeCalculation* calc) override
+    {
+        return ::feeEstimator.estimateSmartFee(num_blocks, calc, conservative);
+    }
+    unsigned int estimateMaxBlocks() override
+    {
+        return ::feeEstimator.HighestTargetTracked(FeeEstimateHorizon::LONG_HALFLIFE);
+    }
+    CFeeRate mempoolMinFee() override
+    {
+        if (!m_node.mempool) return {};
+        return m_node.mempool->GetMinFee(gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000);
+    }
+    CFeeRate relayMinFee() override { return ::minRelayTxFee; }
+    CFeeRate relayIncrementalFee() override { return ::incrementalRelayFee; }
+    CFeeRate relayDustFee() override { return ::dustRelayFee; }
+    bool havePruned() override
+    {
+        LOCK(cs_main);
+        return ::fHavePruned;
+    }
+    bool isReadyToBroadcast() override { return !::fImporting && !::fReindex && !isInitialBlockDownload(); }
+    bool isInitialBlockDownload() override { return ::ChainstateActive().IsInitialBlockDownload(); }
+    bool shutdownRequested() override { return ShutdownRequested(); }
+    int64_t getAdjustedTime() override { return GetAdjustedTime(); }
+    void initMessage(const std::string& message) override { ::uiInterface.InitMessage(message); }
+    void initWarning(const bilingual_str& message) override { InitWarning(message); }
+    void initError(const bilingual_str& message) override { InitError(message); }
+    void showProgress(const std::string& title, int progress, bool resume_possible) override
+    {
+        ::uiInterface.ShowProgress(title, progress, resume_possible);
+    }
+    std::unique_ptr<Handler> handleNotifications(std::shared_ptr<Notifications> notifications) override
+    {
+        return MakeUnique<NotificationsHandlerImpl>(std::move(notifications));
+    }
+    void waitForNotificationsIfTipChanged(const uint256& old_tip) override
+    {
+        if (!old_tip.IsNull()) {
+            LOCK(::cs_main);
+            if (old_tip == ::ChainActive().Tip()->GetBlockHash()) return;
+        }
+        SyncWithValidationInterfaceQueue();
+    }
+    std::unique_ptr<Handler> handleRpc(const CRPCCommand& command) override
+    {
+        return MakeUnique<RpcHandlerImpl>(command);
+    }
+    bool rpcEnableDeprecated(const std::string& method) override { return IsDeprecatedRPCEnabled(method); }
+    void rpcRunLater(const std::string& name, std::function<void()> fn, int64_t seconds) override
+    {
+        RPCRunLater(name, std::move(fn), seconds);
+    }
+    int rpcSerializationFlags() override { return RPCSerializationFlags(); }
+    util::SettingsValue getRwSetting(const std::string& name) override
+    {
+        util::SettingsValue result;
+        gArgs.LockSettings([&](const util::Settings& settings) {
+            if (const util::SettingsValue* value = util::FindKey(settings.rw_settings, name)) {
+                result = *value;
+            }
+        });
+        return result;
+    }
+    bool updateRwSetting(const std::string& name, const util::SettingsValue& value) override
+    {
+        gArgs.LockSettings([&](util::Settings& settings) {
+            if (value.isNull()) {
+                settings.rw_settings.erase(name);
+            } else {
+                settings.rw_settings[name] = value;
+            }
+        });
+        return gArgs.WriteSettingsFile();
+    }
+    void requestMempoolTransactions(Notifications& notifications) override
+    {
+        if (!m_node.mempool) return;
+        LOCK2(::cs_main, m_node.mempool->cs);
+        for (const CTxMemPoolEntry& entry : m_node.mempool->mapTx) {
+            notifications.transactionAddedToMempool(entry.GetSharedTx(), 0 /* mempool_sequence */);
+        }
+    }
+    NodeContext& m_node;
+};
+} // namespace
+} // namespace node
+
+namespace interfaces {
+std::unique_ptr<Node> MakeNode(NodeContext* context) { return MakeUnique<node::NodeImpl>(context); }
+std::unique_ptr<Chain> MakeChain(NodeContext& context) { return MakeUnique<node::ChainImpl>(context); }
+} // namespace interfaces