1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
|
// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2020 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_VALIDATIONINTERFACE_H
#define BITCOIN_VALIDATIONINTERFACE_H
#include <primitives/transaction.h> // CTransaction(Ref)
#include <sync.h>
#include <functional>
#include <memory>
extern RecursiveMutex cs_main;
class BlockValidationState;
class CBlock;
class CBlockIndex;
struct CBlockLocator;
class CConnman;
class CValidationInterface;
class uint256;
class CScheduler;
enum class MemPoolRemovalReason;
/** Register subscriber */
void RegisterValidationInterface(CValidationInterface* callbacks);
/** Unregister subscriber. DEPRECATED. This is not safe to use when the RPC server or main message handler thread is running. */
void UnregisterValidationInterface(CValidationInterface* callbacks);
/** Unregister all subscribers */
void UnregisterAllValidationInterfaces();
// Alternate registration functions that release a shared_ptr after the last
// notification is sent. These are useful for race-free cleanup, since
// unregistration is nonblocking and can return before the last notification is
// processed.
/** Register subscriber */
void RegisterSharedValidationInterface(std::shared_ptr<CValidationInterface> callbacks);
/** Unregister subscriber */
void UnregisterSharedValidationInterface(std::shared_ptr<CValidationInterface> callbacks);
/**
* Pushes a function to callback onto the notification queue, guaranteeing any
* callbacks generated prior to now are finished when the function is called.
*
* Be very careful blocking on func to be called if any locks are held -
* validation interface clients may not be able to make progress as they often
* wait for things like cs_main, so blocking until func is called with cs_main
* will result in a deadlock (that DEBUG_LOCKORDER will miss).
*/
void CallFunctionInValidationInterfaceQueue(std::function<void ()> func);
/**
* This is a synonym for the following, which asserts certain locks are not
* held:
* std::promise<void> promise;
* CallFunctionInValidationInterfaceQueue([&promise] {
* promise.set_value();
* });
* promise.get_future().wait();
*/
void SyncWithValidationInterfaceQueue() LOCKS_EXCLUDED(cs_main);
/**
* Implement this to subscribe to events generated in validation
*
* Each CValidationInterface() subscriber will receive event callbacks
* in the order in which the events were generated by validation.
* Furthermore, each ValidationInterface() subscriber may assume that
* callbacks effectively run in a single thread with single-threaded
* memory consistency. That is, for a given ValidationInterface()
* instantiation, each callback will complete before the next one is
* invoked. This means, for example when a block is connected that the
* UpdatedBlockTip() callback may depend on an operation performed in
* the BlockConnected() callback without worrying about explicit
* synchronization. No ordering should be assumed across
* ValidationInterface() subscribers.
*/
class CValidationInterface {
protected:
/**
* Protected destructor so that instances can only be deleted by derived classes.
* If that restriction is no longer desired, this should be made public and virtual.
*/
~CValidationInterface() = default;
/**
* Notifies listeners when the block chain tip advances.
*
* When multiple blocks are connected at once, UpdatedBlockTip will be called on the final tip
* but may not be called on every intermediate tip. If the latter behavior is desired,
* subscribe to BlockConnected() instead.
*
* Called on a background thread.
*/
virtual void UpdatedBlockTip(const CBlockIndex *pindexNew, const CBlockIndex *pindexFork, bool fInitialDownload) {}
/**
* Notifies listeners of a transaction having been added to mempool.
*
* Called on a background thread.
*/
virtual void TransactionAddedToMempool(const CTransactionRef& tx, uint64_t mempool_sequence) {}
/**
* Notifies listeners of a transaction leaving mempool.
*
* This notification fires for transactions that are removed from the
* mempool for the following reasons:
*
* - EXPIRY (expired from mempool after -mempoolexpiry hours)
* - SIZELIMIT (removed in size limiting if the mempool exceeds -maxmempool megabytes)
* - REORG (removed during a reorg)
* - CONFLICT (removed because it conflicts with in-block transaction)
* - REPLACED (removed due to RBF replacement)
*
* This does not fire for transactions that are removed from the mempool
* because they have been included in a block. Any client that is interested
* in transactions removed from the mempool for inclusion in a block can learn
* about those transactions from the BlockConnected notification.
*
* Transactions that are removed from the mempool because they conflict
* with a transaction in the new block will have
* TransactionRemovedFromMempool events fired *before* the BlockConnected
* event is fired. If multiple blocks are connected in one step, then the
* ordering could be:
*
* - TransactionRemovedFromMempool(tx1 from block A)
* - TransactionRemovedFromMempool(tx2 from block A)
* - TransactionRemovedFromMempool(tx1 from block B)
* - TransactionRemovedFromMempool(tx2 from block B)
* - BlockConnected(A)
* - BlockConnected(B)
*
* Called on a background thread.
*/
virtual void TransactionRemovedFromMempool(const CTransactionRef& tx, MemPoolRemovalReason reason, uint64_t mempool_sequence) {}
/**
* Notifies listeners of a block being connected.
* Provides a vector of transactions evicted from the mempool as a result.
*
* Called on a background thread.
*/
virtual void BlockConnected(const std::shared_ptr<const CBlock> &block, const CBlockIndex *pindex) {}
/**
* Notifies listeners of a block being disconnected
*
* Called on a background thread.
*/
virtual void BlockDisconnected(const std::shared_ptr<const CBlock> &block, const CBlockIndex* pindex) {}
/**
* Notifies listeners of the new active block chain on-disk.
*
* Prior to this callback, any updates are not guaranteed to persist on disk
* (ie clients need to handle shutdown/restart safety by being able to
* understand when some updates were lost due to unclean shutdown).
*
* When this callback is invoked, the validation changes done by any prior
* callback are guaranteed to exist on disk and survive a restart, including
* an unclean shutdown.
*
* Provides a locator describing the best chain, which is likely useful for
* storing current state on disk in client DBs.
*
* Called on a background thread.
*/
virtual void ChainStateFlushed(const CBlockLocator &locator) {}
/**
* Notifies listeners of a block validation result.
* If the provided BlockValidationState IsValid, the provided block
* is guaranteed to be the current best block at the time the
* callback was generated (not necessarily now)
*/
virtual void BlockChecked(const CBlock&, const BlockValidationState&) {}
/**
* Notifies listeners that a block which builds directly on our current tip
* has been received and connected to the headers tree, though not validated yet */
virtual void NewPoWValidBlock(const CBlockIndex *pindex, const std::shared_ptr<const CBlock>& block) {};
friend class CMainSignals;
};
struct MainSignalsInstance;
class CMainSignals {
private:
std::unique_ptr<MainSignalsInstance> m_internals;
friend void ::RegisterSharedValidationInterface(std::shared_ptr<CValidationInterface>);
friend void ::UnregisterValidationInterface(CValidationInterface*);
friend void ::UnregisterAllValidationInterfaces();
friend void ::CallFunctionInValidationInterfaceQueue(std::function<void ()> func);
public:
/** Register a CScheduler to give callbacks which should run in the background (may only be called once) */
void RegisterBackgroundSignalScheduler(CScheduler& scheduler);
/** Unregister a CScheduler to give callbacks which should run in the background - these callbacks will now be dropped! */
void UnregisterBackgroundSignalScheduler();
/** Call any remaining callbacks on the calling thread */
void FlushBackgroundCallbacks();
size_t CallbacksPending();
void UpdatedBlockTip(const CBlockIndex *, const CBlockIndex *, bool fInitialDownload);
void TransactionAddedToMempool(const CTransactionRef&, uint64_t mempool_sequence);
void TransactionRemovedFromMempool(const CTransactionRef&, MemPoolRemovalReason, uint64_t mempool_sequence);
void BlockConnected(const std::shared_ptr<const CBlock> &, const CBlockIndex *pindex);
void BlockDisconnected(const std::shared_ptr<const CBlock> &, const CBlockIndex* pindex);
void ChainStateFlushed(const CBlockLocator &);
void BlockChecked(const CBlock&, const BlockValidationState&);
void NewPoWValidBlock(const CBlockIndex *, const std::shared_ptr<const CBlock>&);
};
CMainSignals& GetMainSignals();
#endif // BITCOIN_VALIDATIONINTERFACE_H
|
