// Copyright (c) 2018-2022 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_INTERFACES_CHAIN_H
#define BITCOIN_INTERFACES_CHAIN_H
#include <blockfilter.h>
#include <common/settings.h>
#include <primitives/transaction.h> // For CTransactionRef
#include <util/result.h>
#include <functional>
#include <memory>
#include <optional>
#include <stddef.h>
#include <stdint.h>
#include <string>
#include <vector>
class ArgsManager;
class CBlock;
class CBlockUndo;
class CFeeRate;
class CRPCCommand;
class CScheduler;
class Coin;
class uint256;
enum class MemPoolRemovalReason;
enum class RBFTransactionState;
enum class ChainstateRole;
struct bilingual_str;
struct CBlockLocator;
struct FeeCalculation;
namespace node {
struct NodeContext;
} // namespace node
namespace interfaces {
class Handler;
class Wallet;
//! Hash/height pair to help track and identify blocks.
struct BlockKey {
uint256 hash;
int height = -1;
};
//! Helper for findBlock to selectively return pieces of block data. If block is
//! found, data will be returned by setting specified output variables. If block
//! is not found, output variables will keep their previous values.
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 locator if block is in the active chain.
FoundBlock& locator(CBlockLocator& locator) { m_locator = &locator; 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;
CBlockLocator* m_locator = nullptr;
const FoundBlock* m_next_block = nullptr;
CBlock* m_data = nullptr;
mutable bool found = false;
};
//! Block data sent with blockConnected, blockDisconnected notifications.
struct BlockInfo {
const uint256& hash;
const uint256* prev_hash = nullptr;
int height = -1;
int file_number = -1;
unsigned data_pos = 0;
const CBlock* data = nullptr;
const CBlockUndo* undo_data = nullptr;
// The maximum time in the chain up to and including this block.
// A timestamp that can only move forward.
unsigned int chain_time_max{0};
BlockInfo(const uint256& hash LIFETIMEBOUND) : hash(hash) {}
};
//! 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 bitcoin 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/bitcoin/bitcoin/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/bitcoin/bitcoin/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 a locator that refers to a block in the active chain.
//! If specified block is not in the active chain, return locator for the latest ancestor that is in the chain.
virtual CBlockLocator getActiveChainLocator(const uint256& block_hash) = 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;
//! Returns whether a block filter index is available.
virtual bool hasBlockFilterIndex(BlockFilterType filter_type) = 0;
//! Returns whether any of the elements match the block via a BIP 157 block filter
//! or std::nullopt if the block filter for this block couldn't be found.
virtual std::optional<bool> blockFilterMatchesAny(BlockFilterType filter_type, const uint256& block_hash, const GCSFilter::ElementSet& filter_set) = 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, size_t* ancestorsize = nullptr, CAmount* ancestorfees = nullptr) = 0;
//! For each outpoint, calculate the fee-bumping cost to spend this outpoint at the specified
// feerate, including bumping its ancestors. For example, if the target feerate is 10sat/vbyte
// and this outpoint refers to a mempool transaction at 3sat/vbyte, the bump fee includes the
// cost to bump the mempool transaction to 10sat/vbyte (i.e. 7 * mempooltx.vsize). If that
// transaction also has, say, an unconfirmed parent with a feerate of 1sat/vbyte, the bump fee
// includes the cost to bump the parent (i.e. 9 * parentmempooltx.vsize).
//
// If the outpoint comes from an unconfirmed transaction that is already above the target
// feerate or bumped by its descendant(s) already, it does not need to be bumped. Its bump fee
// is 0. Likewise, if any of the transaction's ancestors are already bumped by a transaction
// in our mempool, they are not included in the transaction's bump fee.
//
// Also supported is bump-fee calculation in the case of replacements. If an outpoint
// conflicts with another transaction in the mempool, it is assumed that the goal is to replace
// that transaction. As such, the calculation will exclude the to-be-replaced transaction, but
// will include the fee-bumping cost. If bump fees of descendants of the to-be-replaced
// transaction are requested, the value will be 0. Fee-related RBF rules are not included as
// they are logically distinct.
//
// Any outpoints that are otherwise unavailable from the mempool (e.g. UTXOs from confirmed
// transactions or transactions not yet broadcast by the wallet) are given a bump fee of 0.
//
// If multiple outpoints come from the same transaction (which would be very rare because
// it means that one transaction has multiple change outputs or paid the same wallet using multiple
// outputs in the same transaction) or have shared ancestry, the bump fees are calculated
// independently, i.e. as if only one of them is spent. This may result in double-fee-bumping. This
// caveat can be rectified per use of the sister-function CalculateCombinedBumpFee(…).
virtual std::map<COutPoint, CAmount> calculateIndividualBumpFees(const std::vector<COutPoint>& outpoints, const CFeeRate& target_feerate) = 0;
//! Calculate the combined bump fee for an input set per the same strategy
// as in CalculateIndividualBumpFees(…).
// Unlike CalculateIndividualBumpFees(…), this does not return individual
// bump fees per outpoint, but a single bump fee for the shared ancestry.
// The combined bump fee may be used to correct overestimation due to
// shared ancestry by multiple UTXOs after coin selection.
virtual std::optional<CAmount> calculateCombinedBumpFee(const std::vector<COutPoint>& outpoints, const CFeeRate& target_feerate) = 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 util::Result<void> 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;
//! 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) {}
virtual void transactionRemovedFromMempool(const CTransactionRef& tx, MemPoolRemovalReason reason) {}
virtual void blockConnected(ChainstateRole role, const BlockInfo& block) {}
virtual void blockDisconnected(const BlockInfo& block) {}
virtual void updatedBlockTip() {}
virtual void chainStateFlushed(ChainstateRole role, 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;
//! Get settings value.
virtual common::SettingsValue getSetting(const std::string& arg) = 0;
//! Get list of settings values.
virtual std::vector<common::SettingsValue> getSettingsList(const std::string& arg) = 0;
//! Return <datadir>/settings.json setting value.
virtual common::SettingsValue getRwSetting(const std::string& name) = 0;
//! Write a setting to <datadir>/settings.json. Optionally just update the
//! setting in memory and do not write the file.
virtual bool updateRwSetting(const std::string& name, const common::SettingsValue& value, bool write=true) = 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;
//! Return true if an assumed-valid chain is in use.
virtual bool hasAssumedValidChain() = 0;
//! Get internal node context. Useful for testing, but not
//! accessible across processes.
virtual node::NodeContext* context() { return nullptr; }
};
//! 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;
//! Mock the scheduler to fast forward in time.
virtual void schedulerMockForward(std::chrono::seconds delta_seconds) = 0;
};
//! Return implementation of Chain interface.
std::unique_ptr<Chain> MakeChain(node::NodeContext& node);
} // namespace interfaces
#endif // BITCOIN_INTERFACES_CHAIN_H
