Merge bitcoin/bitcoin#32694: index: move disk read lookups to base class

029ba1a21d index: remove CBlockIndex access from CustomAppend() (furszy)
91b7ab6c69 refactor: index, simplify CopyHeightIndexToHashIndex to process single block (furszy)
6f1392cc42 indexes, refactor: Remove remaining CBlockIndex* uses in index Rewind methods (Ryan Ofsky)
0a248708dc indexes, refactor: Stop requiring CBlockIndex type to call IsBIP30Unspendable (Ryan Ofsky)
331a25cb16 test: indexes, avoid creating threads when sync runs synchronously (furszy)

Pull request description:

  Combining common refactors from #24230 and #26966, aiming to move both efforts forward while reducing their size and review burden.

  Broadly, #24230 focuses on enabling indexes to run in a separate process, and #26966 aims to parallelize the indexes initial synchronization process. A shared prerequisite for both is ensuring that only the base index class interacts with the node’s chain internals - child index classes should instead operate solely through chain events.

  This PR moves disk read lookups from child index classes to the base index class. It also includes a few documentation improvements and a test-only code cleanup.

ACKs for top commit:
  maflcko:
    review ACK 029ba1a21d 👡
  achow101:
    ACK 029ba1a21d
  TheCharlatan:
    Re-ACK 029ba1a21d
  davidgumberg:
    ACK 029ba1a21d
  mzumsande:
    Code Review ACK 029ba1a21d

Tree-SHA512: f073af407fc86f228cb47a32c7bcf2241551cc89ff32059317eb81d5b86fd5fda35f228d2567e0aedbc9fd6826291f5fee05619db35ba44108421ae04d11e6fb

src/test/blockfilter_index_tests.cpp

@@ -12,7 +12,6 @@
 #include <node/miner.h>
 #include <pow.h>
 #include <test/util/blockfilter.h>
-#include <test/util/index.h>
 #include <test/util/setup_common.h>
 #include <validation.h>
 
@@ -143,10 +142,7 @@ BOOST_FIXTURE_TEST_CASE(blockfilter_index_initial_sync, BuildChainTestingSetup)
     // BlockUntilSyncedToCurrentChain should return false before index is started.
     BOOST_CHECK(!filter_index.BlockUntilSyncedToCurrentChain());
 
-    BOOST_REQUIRE(filter_index.StartBackgroundSync());
-
-    // Allow filter index to catch up with the block index.
-    IndexWaitSynced(filter_index, *Assert(m_node.shutdown_signal));
+    filter_index.Sync();
 
     // Check that filter index has all blocks that were in the chain before it started.
     {

src/test/coinstatsindex_tests.cpp

@@ -6,7 +6,6 @@
 #include <index/coinstatsindex.h>
 #include <interfaces/chain.h>
 #include <kernel/coinstats.h>
-#include <test/util/index.h>
 #include <test/util/setup_common.h>
 #include <test/util/validation.h>
 #include <validation.h>
@@ -33,9 +32,7 @@ BOOST_FIXTURE_TEST_CASE(coinstatsindex_initial_sync, TestChain100Setup)
     // is started.
     BOOST_CHECK(!coin_stats_index.BlockUntilSyncedToCurrentChain());
 
-    BOOST_REQUIRE(coin_stats_index.StartBackgroundSync());
-
-    IndexWaitSynced(coin_stats_index, *Assert(m_node.shutdown_signal));
+    coin_stats_index.Sync();
 
     // Check that CoinStatsIndex works for genesis block.
     const CBlockIndex* genesis_block_index;
@@ -85,8 +82,7 @@ BOOST_FIXTURE_TEST_CASE(coinstatsindex_unclean_shutdown, TestChain100Setup)
     {
         CoinStatsIndex index{interfaces::MakeChain(m_node), 1 << 20};
         BOOST_REQUIRE(index.Init());
-        BOOST_REQUIRE(index.StartBackgroundSync());
-        IndexWaitSynced(index, *Assert(m_node.shutdown_signal));
+        index.Sync();
         std::shared_ptr<const CBlock> new_block;
         CBlockIndex* new_block_index = nullptr;
         {

src/test/txindex_tests.cpp

@@ -6,7 +6,6 @@
 #include <chainparams.h>
 #include <index/txindex.h>
 #include <interfaces/chain.h>
-#include <test/util/index.h>
 #include <test/util/setup_common.h>
 #include <validation.h>
 
@@ -30,10 +29,7 @@ BOOST_FIXTURE_TEST_CASE(txindex_initial_sync, TestChain100Setup)
     // BlockUntilSyncedToCurrentChain should return false before txindex is started.
     BOOST_CHECK(!txindex.BlockUntilSyncedToCurrentChain());
 
-    BOOST_REQUIRE(txindex.StartBackgroundSync());
-
-    // Allow tx index to catch up with the block index.
-    IndexWaitSynced(txindex, *Assert(m_node.shutdown_signal));
+    txindex.Sync();
 
     // Check that txindex excludes genesis block transactions.
     const CBlock& genesis_block = Params().GenesisBlock();

src/test/util/CMakeLists.txt

@@ -6,7 +6,6 @@ add_library(test_util STATIC EXCLUDE_FROM_ALL
   blockfilter.cpp
   coins.cpp
   coverage.cpp
-  index.cpp
   json.cpp
   logging.cpp
   mining.cpp

src/test/util/index.cpp

@@ -1,22 +0,0 @@
-// Copyright (c) 2020-2022 The Bitcoin Core developers
-// Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
-
-#include <test/util/index.h>
-
-#include <index/base.h>
-#include <util/check.h>
-#include <util/signalinterrupt.h>
-#include <util/time.h>
-
-void IndexWaitSynced(const BaseIndex& index, const util::SignalInterrupt& interrupt)
-{
-    while (!index.BlockUntilSyncedToCurrentChain()) {
-        // Assert shutdown was not requested to abort the test, instead of looping forever, in case
-        // there was an unexpected error in the index that caused it to stop syncing and request a shutdown.
-        Assert(!interrupt);
-
-        UninterruptibleSleep(100ms);
-    }
-    assert(index.GetSummary().synced);
-}

src/test/util/index.h

@@ -1,16 +0,0 @@
-// Copyright (c) 2020-2022 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_TEST_UTIL_INDEX_H
-#define BITCOIN_TEST_UTIL_INDEX_H
-
-class BaseIndex;
-namespace util {
-class SignalInterrupt;
-} // namespace util
-
-/** Block until the index is synced to the current chain */
-void IndexWaitSynced(const BaseIndex& index, const util::SignalInterrupt& interrupt);
-
-#endif // BITCOIN_TEST_UTIL_INDEX_H