1 // Copyright (c) 2018-present The Bitcoin Core developers
2 // Distributed under the MIT software license, see the accompanying
3 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
4 5 #ifndef BITCOIN_INTERFACES_CHAIN_H
6 #define BITCOIN_INTERFACES_CHAIN_H
7 8 #include <blockfilter.h>
9 #include <common/settings.h>
10 #include <kernel/chain.h> // IWYU pragma: export
11 #include <node/types.h>
12 #include <primitives/transaction.h>
13 #include <util/result.h>
14 15 #include <cstddef>
16 #include <cstdint>
17 #include <functional>
18 #include <map>
19 #include <memory>
20 #include <optional>
21 #include <string>
22 #include <vector>
23 24 class ArgsManager;
25 class CBlock;
26 class CBlockUndo;
27 class CFeeRate;
28 class CRPCCommand;
29 class CScheduler;
30 class Coin;
31 class uint256;
32 enum class MemPoolRemovalReason;
33 enum class RBFTransactionState;
34 struct bilingual_str;
35 struct CBlockLocator;
36 struct FeeCalculation;
37 namespace kernel {
38 struct ChainstateRole;
39 } // namespace kernel
40 namespace node {
41 struct NodeContext;
42 } // namespace node
43 44 namespace interfaces {
45 46 class Handler;
47 class Wallet;
48 49 //! Helper for findBlock to selectively return pieces of block data. If block is
50 //! found, data will be returned by setting specified output variables. If block
51 //! is not found, output variables will keep their previous values.
52 class FoundBlock
53 {
54 public:
55 FoundBlock& hash(uint256& hash) { m_hash = &hash; return *this; }
56 FoundBlock& height(int& height) { m_height = &height; return *this; }
57 FoundBlock& time(int64_t& time) { m_time = &time; return *this; }
58 FoundBlock& maxTime(int64_t& max_time) { m_max_time = &max_time; return *this; }
59 FoundBlock& mtpTime(int64_t& mtp_time) { m_mtp_time = &mtp_time; return *this; }
60 //! Return whether block is in the active (most-work) chain.
61 FoundBlock& inActiveChain(bool& in_active_chain) { m_in_active_chain = &in_active_chain; return *this; }
62 //! Return locator if block is in the active chain.
63 FoundBlock& locator(CBlockLocator& locator) { m_locator = &locator; return *this; }
64 //! Return next block in the active chain if current block is in the active chain.
65 FoundBlock& nextBlock(const FoundBlock& next_block) { m_next_block = &next_block; return *this; }
66 //! Read block data from disk. If the block exists but doesn't have data
67 //! (for example due to pruning), the CBlock variable will be set to null.
68 FoundBlock& data(CBlock& data) { m_data = &data; return *this; }
69 70 uint256* m_hash = nullptr;
71 int* m_height = nullptr;
72 int64_t* m_time = nullptr;
73 int64_t* m_max_time = nullptr;
74 int64_t* m_mtp_time = nullptr;
75 bool* m_in_active_chain = nullptr;
76 CBlockLocator* m_locator = nullptr;
77 const FoundBlock* m_next_block = nullptr;
78 CBlock* m_data = nullptr;
79 mutable bool found = false;
80 };
81 82 //! The action to be taken after updating a settings value.
83 //! WRITE indicates that the updated value must be written to disk,
84 //! while SKIP_WRITE indicates that the change will be kept in memory-only
85 //! without persisting it.
86 enum class SettingsAction {
87 WRITE,
88 SKIP_WRITE
89 };
90 91 using SettingsUpdate = std::function<std::optional<interfaces::SettingsAction>(common::SettingsValue&)>;
92 93 //! Interface giving clients (wallet processes, maybe other analysis tools in
94 //! the future) ability to access to the chain state, receive notifications,
95 //! estimate fees, and submit transactions.
96 //!
97 //! TODO: Current chain methods are too low level, exposing too much of the
98 //! internal workings of the bitcoin node, and not being very convenient to use.
99 //! Chain methods should be cleaned up and simplified over time. Examples:
100 //!
101 //! * The initMessages() and showProgress() methods which the wallet uses to send
102 //! notifications to the GUI should go away when GUI and wallet can directly
103 //! communicate with each other without going through the node
104 //! (https://github.com/bitcoin/bitcoin/pull/15288#discussion_r253321096).
105 //!
106 //! * The handleRpc, registerRpcs, rpcEnableDeprecated methods and other RPC
107 //! methods can go away if wallets listen for HTTP requests on their own
108 //! ports instead of registering to handle requests on the node HTTP port.
109 //!
110 //! * Move fee estimation queries to an asynchronous interface and let the
111 //! wallet cache it, fee estimation being driven by node mempool, wallet
112 //! should be the consumer.
113 //!
114 //! * `guessVerificationProgress` and similar methods can go away if rescan
115 //! logic moves out of the wallet, and the wallet just requests scans from the
116 //! node (https://github.com/bitcoin/bitcoin/issues/11756)
117 class Chain
118 {
119 public:
120 virtual ~Chain() = default;
121 122 //! Get current chain height, not including genesis block (returns 0 if
123 //! chain only contains genesis block, nullopt if chain does not contain
124 //! any blocks)
125 virtual std::optional<int> getHeight() = 0;
126 127 //! Get block hash. Height must be valid or this function will abort.
128 virtual uint256 getBlockHash(int height) = 0;
129 130 //! Check that the block is available on disk (i.e. has not been
131 //! pruned), and contains transactions.
132 virtual bool haveBlockOnDisk(int height) = 0;
133 134 //! Return height of the highest block on chain in common with the locator,
135 //! which will either be the original block used to create the locator,
136 //! or one of its ancestors.
137 virtual std::optional<int> findLocatorFork(const CBlockLocator& locator) = 0;
138 139 //! Returns whether a block filter index is available.
140 virtual bool hasBlockFilterIndex(BlockFilterType filter_type) = 0;
141 142 //! Returns whether any of the elements match the block via a BIP 157 block filter
143 //! or std::nullopt if the block filter for this block couldn't be found.
144 virtual std::optional<bool> blockFilterMatchesAny(BlockFilterType filter_type, const uint256& block_hash, const GCSFilter::ElementSet& filter_set) = 0;
145 146 //! Return whether node has the block and optionally return block metadata
147 //! or contents.
148 virtual bool findBlock(const uint256& hash, const FoundBlock& block={}) = 0;
149 150 //! Find first block in the chain with timestamp >= the given time
151 //! and height >= than the given height, return false if there is no block
152 //! with a high enough timestamp and height. Optionally return block
153 //! information.
154 virtual bool findFirstBlockWithTimeAndHeight(int64_t min_time, int min_height, const FoundBlock& block={}) = 0;
155 156 //! Find ancestor of block at specified height and optionally return
157 //! ancestor information.
158 virtual bool findAncestorByHeight(const uint256& block_hash, int ancestor_height, const FoundBlock& ancestor_out={}) = 0;
159 160 //! Return whether block descends from a specified ancestor, and
161 //! optionally return ancestor information.
162 virtual bool findAncestorByHash(const uint256& block_hash,
163 const uint256& ancestor_hash,
164 const FoundBlock& ancestor_out={}) = 0;
165 166 //! Find most recent common ancestor between two blocks and optionally
167 //! return block information.
168 virtual bool findCommonAncestor(const uint256& block_hash1,
169 const uint256& block_hash2,
170 const FoundBlock& ancestor_out={},
171 const FoundBlock& block1_out={},
172 const FoundBlock& block2_out={}) = 0;
173 174 //! Look up unspent output information. Returns coins in the mempool and in
175 //! the current chain UTXO set. Iterates through all the keys in the map and
176 //! populates the values.
177 virtual void findCoins(std::map<COutPoint, Coin>& coins) = 0;
178 179 //! Estimate fraction of total transactions verified if blocks up to
180 //! the specified block hash are verified.
181 virtual double guessVerificationProgress(const uint256& block_hash) = 0;
182 183 //! Return true if data is available for all blocks in the specified range
184 //! of blocks. This checks all blocks that are ancestors of block_hash in
185 //! the height range from min_height to max_height, inclusive.
186 virtual bool hasBlocks(const uint256& block_hash, int min_height = 0, std::optional<int> max_height = {}) = 0;
187 188 //! Check if transaction is RBF opt in.
189 virtual RBFTransactionState isRBFOptIn(const CTransaction& tx) = 0;
190 191 //! Check if transaction is in mempool.
192 virtual bool isInMempool(const Txid& txid) = 0;
193 194 //! Check if transaction has descendants in mempool.
195 virtual bool hasDescendantsInMempool(const Txid& txid) = 0;
196 197 //! Process a local transaction, optionally adding it to the mempool and
198 //! optionally broadcasting it to the network.
199 //! @param[in] tx Transaction to process.
200 //! @param[in] max_tx_fee Don't add the transaction to the mempool or
201 //! broadcast it if its fee is higher than this.
202 //! @param[in] broadcast_method Whether to add the transaction to the
203 //! mempool and how/whether to broadcast it.
204 //! @param[out] err_string Set if an error occurs.
205 //! @return False if the transaction could not be added due to the fee or for another reason.
206 virtual bool broadcastTransaction(const CTransactionRef& tx,
207 const CAmount& max_tx_fee,
208 node::TxBroadcast broadcast_method,
209 std::string& err_string) = 0;
210 211 //! Calculate mempool ancestor and cluster counts for the given transaction.
212 virtual void getTransactionAncestry(const Txid& txid, size_t& ancestors, size_t& cluster_count, size_t* ancestorsize = nullptr, CAmount* ancestorfees = nullptr) = 0;
213 214 //! For each outpoint, calculate the fee-bumping cost to spend this outpoint at the specified
215 // feerate, including bumping its ancestors. For example, if the target feerate is 10sat/vbyte
216 // and this outpoint refers to a mempool transaction at 3sat/vbyte, the bump fee includes the
217 // cost to bump the mempool transaction to 10sat/vbyte (i.e. 7 * mempooltx.vsize). If that
218 // transaction also has, say, an unconfirmed parent with a feerate of 1sat/vbyte, the bump fee
219 // includes the cost to bump the parent (i.e. 9 * parentmempooltx.vsize).
220 //
221 // If the outpoint comes from an unconfirmed transaction that is already above the target
222 // feerate or bumped by its descendant(s) already, it does not need to be bumped. Its bump fee
223 // is 0. Likewise, if any of the transaction's ancestors are already bumped by a transaction
224 // in our mempool, they are not included in the transaction's bump fee.
225 //
226 // Also supported is bump-fee calculation in the case of replacements. If an outpoint
227 // conflicts with another transaction in the mempool, it is assumed that the goal is to replace
228 // that transaction. As such, the calculation will exclude the to-be-replaced transaction, but
229 // will include the fee-bumping cost. If bump fees of descendants of the to-be-replaced
230 // transaction are requested, the value will be 0. Fee-related RBF rules are not included as
231 // they are logically distinct.
232 //
233 // Any outpoints that are otherwise unavailable from the mempool (e.g. UTXOs from confirmed
234 // transactions or transactions not yet broadcast by the wallet) are given a bump fee of 0.
235 //
236 // If multiple outpoints come from the same transaction (which would be very rare because
237 // it means that one transaction has multiple change outputs or paid the same wallet using multiple
238 // outputs in the same transaction) or have shared ancestry, the bump fees are calculated
239 // independently, i.e. as if only one of them is spent. This may result in double-fee-bumping. This
240 // caveat can be rectified per use of the sister-function CalculateCombinedBumpFee(…).
241 virtual std::map<COutPoint, CAmount> calculateIndividualBumpFees(const std::vector<COutPoint>& outpoints, const CFeeRate& target_feerate) = 0;
242 243 //! Calculate the combined bump fee for an input set per the same strategy
244 // as in CalculateIndividualBumpFees(…).
245 // Unlike CalculateIndividualBumpFees(…), this does not return individual
246 // bump fees per outpoint, but a single bump fee for the shared ancestry.
247 // The combined bump fee may be used to correct overestimation due to
248 // shared ancestry by multiple UTXOs after coin selection.
249 virtual std::optional<CAmount> calculateCombinedBumpFee(const std::vector<COutPoint>& outpoints, const CFeeRate& target_feerate) = 0;
250 251 //! Get the node's package limits.
252 //! Currently only returns the ancestor and descendant count limits, but could be enhanced to
253 //! return more policy settings.
254 virtual void getPackageLimits(unsigned int& limit_ancestor_count, unsigned int& limit_descendant_count) = 0;
255 256 //! Check if transaction will pass the mempool's chain limits.
257 virtual util::Result<void> checkChainLimits(const CTransactionRef& tx) = 0;
258 259 //! Estimate smart fee.
260 virtual CFeeRate estimateSmartFee(int num_blocks, bool conservative, FeeCalculation* calc = nullptr) = 0;
261 262 //! Fee estimator max target.
263 virtual unsigned int estimateMaxBlocks() = 0;
264 265 //! Mempool minimum fee.
266 virtual CFeeRate mempoolMinFee() = 0;
267 268 //! Relay current minimum fee (from -minrelaytxfee and -incrementalrelayfee settings).
269 virtual CFeeRate relayMinFee() = 0;
270 271 //! Relay incremental fee setting (-incrementalrelayfee), reflecting cost of relay.
272 virtual CFeeRate relayIncrementalFee() = 0;
273 274 //! Relay dust fee setting (-dustrelayfee), reflecting lowest rate it's economical to spend.
275 virtual CFeeRate relayDustFee() = 0;
276 277 //! Check if any block has been pruned.
278 virtual bool havePruned() = 0;
279 280 //! Get the current prune height.
281 virtual std::optional<int> getPruneHeight() = 0;
282 283 //! Check if the node is ready to broadcast transactions.
284 virtual bool isReadyToBroadcast() = 0;
285 286 //! Check if in IBD.
287 virtual bool isInitialBlockDownload() = 0;
288 289 //! Check if shutdown requested.
290 virtual bool shutdownRequested() = 0;
291 292 //! Send init message.
293 virtual void initMessage(const std::string& message) = 0;
294 295 //! Send init warning.
296 virtual void initWarning(const bilingual_str& message) = 0;
297 298 //! Send init error.
299 virtual void initError(const bilingual_str& message) = 0;
300 301 //! Send progress indicator.
302 virtual void showProgress(const std::string& title, int progress, bool resume_possible) = 0;
303 304 //! Chain notifications.
305 class Notifications
306 {
307 public:
308 virtual ~Notifications() = default;
309 virtual void transactionAddedToMempool(const CTransactionRef& tx) {}
310 virtual void transactionRemovedFromMempool(const CTransactionRef& tx, MemPoolRemovalReason reason) {}
311 virtual void blockConnected(const kernel::ChainstateRole& role, const BlockInfo& block) {}
312 virtual void blockDisconnected(const BlockInfo& block) {}
313 virtual void updatedBlockTip() {}
314 virtual void chainStateFlushed(const kernel::ChainstateRole& role, const CBlockLocator& locator) {}
315 };
316 317 //! Options specifying which chain notifications are required.
318 struct NotifyOptions
319 {
320 //! Include undo data with block connected notifications.
321 bool connect_undo_data = false;
322 //! Include block data with block disconnected notifications.
323 bool disconnect_data = false;
324 //! Include undo data with block disconnected notifications.
325 bool disconnect_undo_data = false;
326 };
327 328 //! Register handler for notifications.
329 //! Some notifications are asynchronous and may still execute after the handler is disconnected.
330 //! Use waitForNotifications() after the handler is disconnected to ensure all pending notifications
331 //! have been processed.
332 virtual std::unique_ptr<Handler> handleNotifications(std::shared_ptr<Notifications> notifications) = 0;
333 334 //! Wait for pending notifications to be processed unless block hash points to the current
335 //! chain tip.
336 virtual void waitForNotificationsIfTipChanged(const uint256& old_tip) = 0;
337 338 //! Wait for all pending notifications up to this point to be processed
339 virtual void waitForNotifications() = 0;
340 341 //! Register handler for RPC. Command is not copied, so reference
342 //! needs to remain valid until Handler is disconnected.
343 virtual std::unique_ptr<Handler> handleRpc(const CRPCCommand& command) = 0;
344 345 //! Check if deprecated RPC is enabled.
346 virtual bool rpcEnableDeprecated(const std::string& method) = 0;
347 348 //! Get settings value.
349 virtual common::SettingsValue getSetting(const std::string& arg) = 0;
350 351 //! Get list of settings values.
352 virtual std::vector<common::SettingsValue> getSettingsList(const std::string& arg) = 0;
353 354 //! Return <datadir>/settings.json setting value.
355 virtual common::SettingsValue getRwSetting(const std::string& name) = 0;
356 357 //! Updates a setting in <datadir>/settings.json.
358 //! Null can be passed to erase the setting. There is intentionally no
359 //! support for writing null values to settings.json.
360 //! Depending on the action returned by the update function, this will either
361 //! update the setting in memory or write the updated settings to disk.
362 virtual bool updateRwSetting(const std::string& name, const SettingsUpdate& update_function) = 0;
363 364 //! Replace a setting in <datadir>/settings.json with a new value.
365 //! Null can be passed to erase the setting.
366 //! This method provides a simpler alternative to updateRwSetting when
367 //! atomically reading and updating the setting is not required.
368 virtual bool overwriteRwSetting(const std::string& name, common::SettingsValue value, SettingsAction action = SettingsAction::WRITE) = 0;
369 370 //! Delete a given setting in <datadir>/settings.json.
371 //! This method provides a simpler alternative to overwriteRwSetting when
372 //! erasing a setting, for ease of use and readability.
373 virtual bool deleteRwSettings(const std::string& name, SettingsAction action = SettingsAction::WRITE) = 0;
374 375 //! Synchronously send transactionAddedToMempool notifications about all
376 //! current mempool transactions to the specified handler and return after
377 //! the last one is sent. These notifications aren't coordinated with async
378 //! notifications sent by handleNotifications, so out of date async
379 //! notifications from handleNotifications can arrive during and after
380 //! synchronous notifications from requestMempoolTransactions. Clients need
381 //! to be prepared to handle this by ignoring notifications about unknown
382 //! removed transactions and already added new transactions.
383 virtual void requestMempoolTransactions(Notifications& notifications) = 0;
384 385 //! Return true if an assumed-valid snapshot is in use. Note that this
386 //! returns true even after the snapshot is validated, until the next node
387 //! restart.
388 virtual bool hasAssumedValidChain() = 0;
389 390 //! Get internal node context. Useful for testing, but not
391 //! accessible across processes.
392 virtual node::NodeContext* context() { return nullptr; }
393 };
394 395 //! Interface to let node manage chain clients (wallets, or maybe tools for
396 //! monitoring and analysis in the future).
397 class ChainClient
398 {
399 public:
400 virtual ~ChainClient() = default;
401 402 //! Register rpcs.
403 virtual void registerRpcs() = 0;
404 405 //! Check for errors before loading.
406 virtual bool verify() = 0;
407 408 //! Load saved state.
409 virtual bool load() = 0;
410 411 //! Start client execution and provide a scheduler.
412 virtual void start(CScheduler& scheduler) = 0;
413 414 //! Shut down client.
415 virtual void stop() = 0;
416 417 //! Set mock time.
418 virtual void setMockTime(int64_t time) = 0;
419 420 //! Mock the scheduler to fast forward in time.
421 virtual void schedulerMockForward(std::chrono::seconds delta_seconds) = 0;
422 };
423 424 //! Return implementation of Chain interface.
425 std::unique_ptr<Chain> MakeChain(node::NodeContext& node);
426 427 } // namespace interfaces
428 429 #endif // BITCOIN_INTERFACES_CHAIN_H
430