Merge bitcoin/bitcoin#19521: Coinstats Index

5f96d7d rpc: gettxoutsetinfo rejects hash_serialized_2 for specific height (Fabian Jahr)
23fe504 test: Add test for coinstatsindex behavior in reorgs (Fabian Jahr)
90c966b rpc: Allow gettxoutsetinfo and getblockstats for stale blocks (Fabian Jahr)
b936239 index, rpc: Add use_index option for gettxoutsetinfo (Fabian Jahr)
bb7788b test: Test coinstatsindex robustness across restarts (Fabian Jahr)
e0938c2 test: Add tests for block_info in gettxoutsetinfo (Fabian Jahr)
2501576 rpc, index: Add verbose amounts tracking to Coinstats index (Fabian Jahr)
655d929 test: add coinstatsindex getindexinfo coverage, improve current tests (Jon Atack)
ca01bb8 rpc: Add Coinstats index to getindexinfo (Fabian Jahr)
57a026c test: Add unit test for Coinstats index (Fabian Jahr)
6a4c0c0 test: Add functional test for Coinstats index (Fabian Jahr)
3f166ec rpc: gettxoutsetinfo can be requested for specific blockheights (Fabian Jahr)
3c914d5 index: Coinstats index can be activated with command line flag (Fabian Jahr)
dd58a4d index: Add Coinstats index (Fabian Jahr)
a8a46c4 refactor: Simplify ApplyStats and ApplyHash (Fabian Jahr)
9c8a265 refactor: Pass hash_type to CoinsStats in stats object (Fabian Jahr)
2e2648a crypto: Make MuHash Remove method efficient (Fabian Jahr)

Pull request description:

  This is part of the coinstats index project tracked in #18000

  While the review of the new UTXO set hash algorithm (MuHash) takes longer recently #19328 was merged which added the possibility to run `gettxoutsetinfo` with a specific hash type. As the first type it added `hash_type=none` which skips the hashing of the UTXO set altogether. This alone did not make `gettxoutsetinfo` much faster but it allows the use of an index for the remaining coin statistics even before a new hashing algorithm has been added. Credit to Sjors for the idea to take this intermediate step.

  Features summary:
  - Users can start their node with the option `-coinstatsindex` which syncs the index in the background
  - After the index is synced the user can  use `gettxoutsetinfo` with `hash_type=none` or `hash_type=muhash` and will get the response instantly out of the index
  - The user can specify a height or block hash when calling `gettxoutsetinfo` to see coin statistics at a specific block height

ACKs for top commit:
  Sjors:
    re-tACK 5f96d7d
  jonatack:
    Code review re-ACK 5f96d7d per `git range-diff 13d27b4 07201d3 5f96d7d`
  promag:
    Tested ACK 5f96d7d. Light code review ACK 5f96d7d.

Tree-SHA512: cbca78bee8e9605c19da4fbcd184625fb280200718396c694a56c7daab6f44ad23ca9fb5456d09f245d8b8d9659fdc2b3f3ce5e953c1c6cf4003dbc74c0463c2

Author: laanwj

src/Makefile.am

@@ -153,6 +153,7 @@ BITCOIN_CORE_H = \
   i2p.h \
   index/base.h \
   index/blockfilterindex.h \
+  index/coinstatsindex.h \
   index/disktxpos.h \
   index/txindex.h \
   indirectmap.h \
@@ -326,6 +327,7 @@ libbitcoin_server_a_SOURCES = \
   i2p.cpp \
   index/base.cpp \
   index/blockfilterindex.cpp \
+  index/coinstatsindex.cpp \
   index/txindex.cpp \
   init.cpp \
   mapport.cpp \

src/Makefile.test.include

@@ -80,6 +80,7 @@ BITCOIN_TESTS =\
   test/bswap_tests.cpp \
   test/checkqueue_tests.cpp \
   test/coins_tests.cpp \
+  test/coinstatsindex_tests.cpp \
   test/compilerbug_tests.cpp \
   test/compress_tests.cpp \
   test/crypto_tests.cpp \

src/crypto/muhash.cpp

@@ -341,6 +341,6 @@ MuHash3072& MuHash3072::Insert(Span<const unsigned char> in) noexcept {
 }
 
 MuHash3072& MuHash3072::Remove(Span<const unsigned char> in) noexcept {
-    m_numerator.Divide(ToNum3072(in));
+    m_denominator.Multiply(ToNum3072(in));
     return *this;
 }

src/index/base.h

@@ -81,6 +81,8 @@ class BaseIndex : public CValidationInterface
 
     void ChainStateFlushed(const CBlockLocator& locator) override;
 
+    const CBlockIndex* CurrentIndex() { return m_best_block_index.load(); };
+
     /// Initialize internal state from the database and block index.
     virtual bool Init();