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bitcoin-bitcoin-core/src/test/validation_chainstate_tests.cpp
Carl Dong 3eb94ec81b
sync: Use decltype(auto) return type for WITH_LOCK
Now that we're using C++17, we can use the decltype(auto) return type
(available since C++14) for functions and lambda expressions.

As demonstrated in this commit, this can simplify cases where previously
the compiler failed to deduce the correct return type.

Just for reference, for the "assign to ref" cases fixed here, there are
3 possible solutions:

- Return a pointer and immediately deref as used before this commit
- Make sure the function/lambda returns declspec(auto) as used after
  this commit
- Class& i = WITH_LOCK(..., return std::ref(...));

-----

References:
1. https://en.cppreference.com/w/cpp/language/function#Return_type_deduction
2. https://en.cppreference.com/w/cpp/language/template_argument_deduction#Other_contexts
3. https://en.cppreference.com/w/cpp/language/auto
4. https://en.cppreference.com/w/cpp/language/decltype

Explanations:
1. https://stackoverflow.com/a/21369192
2. https://stackoverflow.com/a/21369170
3. Item 3 in Effective Modern C++ (Scott Meyers) via jnewbery
2020-12-04 12:23:05 -05:00

75 lines
2.5 KiB
C++

// Copyright (c) 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.
//
#include <random.h>
#include <uint256.h>
#include <consensus/validation.h>
#include <sync.h>
#include <test/util/setup_common.h>
#include <validation.h>
#include <vector>
#include <boost/test/unit_test.hpp>
BOOST_FIXTURE_TEST_SUITE(validation_chainstate_tests, TestingSetup)
//! Test resizing coins-related CChainState caches during runtime.
//!
BOOST_AUTO_TEST_CASE(validation_chainstate_resize_caches)
{
ChainstateManager manager;
CTxMemPool mempool;
//! Create and add a Coin with DynamicMemoryUsage of 80 bytes to the given view.
auto add_coin = [](CCoinsViewCache& coins_view) -> COutPoint {
Coin newcoin;
uint256 txid = InsecureRand256();
COutPoint outp{txid, 0};
newcoin.nHeight = 1;
newcoin.out.nValue = InsecureRand32();
newcoin.out.scriptPubKey.assign((uint32_t)56, 1);
coins_view.AddCoin(outp, std::move(newcoin), false);
return outp;
};
CChainState& c1 = WITH_LOCK(cs_main, return manager.InitializeChainstate(mempool));
c1.InitCoinsDB(
/* cache_size_bytes */ 1 << 23, /* in_memory */ true, /* should_wipe */ false);
WITH_LOCK(::cs_main, c1.InitCoinsCache(1 << 23));
// Add a coin to the in-memory cache, upsize once, then downsize.
{
LOCK(::cs_main);
auto outpoint = add_coin(c1.CoinsTip());
// Set a meaningless bestblock value in the coinsview cache - otherwise we won't
// flush during ResizecoinsCaches() and will subsequently hit an assertion.
c1.CoinsTip().SetBestBlock(InsecureRand256());
BOOST_CHECK(c1.CoinsTip().HaveCoinInCache(outpoint));
c1.ResizeCoinsCaches(
1 << 24, // upsizing the coinsview cache
1 << 22 // downsizing the coinsdb cache
);
// View should still have the coin cached, since we haven't destructed the cache on upsize.
BOOST_CHECK(c1.CoinsTip().HaveCoinInCache(outpoint));
c1.ResizeCoinsCaches(
1 << 22, // downsizing the coinsview cache
1 << 23 // upsizing the coinsdb cache
);
// The view cache should be empty since we had to destruct to downsize.
BOOST_CHECK(!c1.CoinsTip().HaveCoinInCache(outpoint));
}
// Avoid triggering the address sanitizer.
WITH_LOCK(::cs_main, manager.Unload());
}
BOOST_AUTO_TEST_SUITE_END()