Introduce `CoinsViewOverlay`, a `CCoinsViewCache` subclass that reads
coins without mutating the underlying cache via `FetchCoin()`.
Use `PeekCoin()` to look up a Coin through a stack of `CCoinsViewCache` layers without populating parent caches. This prevents the main cache from caching inputs pulled from disk for a block that has not yet been fully validated. Once `Flush()` is called on the view, these inputs will be added as spent to `coinsCache` in the main cache via `BatchWrite()`.
This is the foundation for async input fetching, where worker threads must not
mutate shared state.
Co-authored-by: l0rinc <pap.lorinc@gmail.com>
Introduce a helper to look up a Coin through a stack of CCoinsViewCache layers without populating parent caches.
This is useful for ephemeral views (e.g. during ConnectBlock) that want to avoid polluting CoinsTip() when validating invalid blocks.
Co-authored-by: l0rinc <pap.lorinc@gmail.com>
Co-authored-by: Pieter Wuille <pieter@wuille.net>
Co-authored-by: Ryan Ofsky <ryan@ofsky.org>
3e0fd0e4ddd894f0e7db1772f10ceaa1dddfb951 refactor: rename will_reuse_cache to reallocate_cache (Andrew Toth)
44b4ee194d3bdccd86cf5e151b2fc1479aabbb6c validation: reuse same CCoinsViewCache for every ConnectBlock call (Andrew Toth)
8fb6043231ea396aaa1165b36b082c89e10fcafd coins: introduce CCoinsViewCache::ResetGuard (Andrew Toth)
041758f5eda5725daad4ae20f66c7d19ba02d063 coins: use hashBlock setter internally for CCoinsViewCache methods (Andrew Toth)
8dd9200fc9b0d263f8f75943ce581a925d061378 coins: add Reset on CCoinsViewCache (Andrew Toth)
Pull request description:
This is the first commit of #31132, which can be merged as an independent change. It has a small benefit on its own, but will help in moving the parent PR forward.
Add a `Reset()` method to `CCoinsViewCache` that clears `cacheCoins`, `cachedCoinsUsage`, and `hashBlock` without flushing to the `base` view. This allows efficiently reusing a cache instance across multiple blocks.
Add `CCoinsViewCache::CreateResetGuard` method to return a `CCoinsViewCache::ResetGuard`. The `ResetGuard` automatically calls `Reset()` on destruction. This RAII pattern ensures the cache is always properly reset between blocks.
Add `m_connect_block_view` as a persistent `CCoinsViewCache` for `ConnectBlock`, avoiding repeated memory allocations.
ACKs for top commit:
l0rinc:
ACK 3e0fd0e4ddd894f0e7db1772f10ceaa1dddfb951
achow101:
ACK 3e0fd0e4ddd894f0e7db1772f10ceaa1dddfb951
sedited:
ACK 3e0fd0e4ddd894f0e7db1772f10ceaa1dddfb951
Tree-SHA512: a95feaa062a9eb7cf7514425a7e7adffd347cd1f7b32b4c1fefcde30002141757c184174702b3104a029dcd33194f8bd734159deebb2e668716089305b42cb00
CCoinsViewCache::CreateResetGuard returns a guard that calls
Reset on the cache when the guard goes out of scope.
This RAII pattern ensures the cache is always properly reset
when it leaves current scope.
Co-authored-by: l0rinc <pap.lorinc@gmail.com>
Co-authored-by: sedited <seb.kung@gmail.com>
`CoinsViewBottom` roughly simulates a memory-backed `CCoinsViewDB`, which never stores spent coins.
Stop returning spent coins from `GetCoin()`, erase spent entries in `BatchWrite()`, and tighten comparisons to expect `std::nullopt` when the simulator has no coin.
Co-authored-by: Lőrinc <pap.lorinc@gmail.com>
6da6f503a6dd8de85780ca402f5202095aa8b6ea refactor: Let CCoinsViewCache::BatchWrite return void (TheCharlatan)
Pull request description:
CCoinsViewCache::BatchWrite always returns true if called from a backed cache, so just return void instead. Also return void from ::Sync and ::Flush.
This allows for dropping a FatalError condition and simplifying some dead error handling code a bit.
Since we now no longer exercise the "error path" when returning from `CCoinsView::BatchWrite`, make the method clear the cache instead. This should only be exercised by tests and not change production behaviour. This might slightly improve the coins_view fuzz test's ability to generate better coverage.
ACKs for top commit:
l0rinc:
ACK 6da6f503a6dd8de85780ca402f5202095aa8b6ea
andrewtoth:
re-ACK 6da6f503a6dd8de85780ca402f5202095aa8b6ea
achow101:
ACK 6da6f503a6dd8de85780ca402f5202095aa8b6ea
w0xlt:
ACK 6da6f503a6
Tree-SHA512: dfaa325b0cf8108910aebf1b27434aaddb639d10d860e96797c77ea42eca9035a54a7dc1d6a5d4eae2b75fcc9356206d3d5672243d2c906e80d19024c8b95408
d9319b06cf82664d55f255387a348135fd7f91c7 refactor: unify container presence checks - non-trivial counts (Lőrinc)
039307554eb311ce41648d1f9a12b543f480f871 refactor: unify container presence checks - trivial counts (Lőrinc)
8bb9219b6301215f53e43967d17445aaf1b81090 refactor: unify container presence checks - find (Lőrinc)
Pull request description:
### Summary
Instead of counting occurrences in sets and maps, the C++20 `::contains` method expresses the intent unambiguously and can return early on first encounter.
### Context
Applied clang‑tidy's [readability‑container‑contains](https://clang.llvm.org/extra/clang-tidy/checks/readability/container-contains.html) check, though many cases required manual changes since tidy couldn't fix them automatically.
### Changes
The changes made here were:
| From | To |
|------------------------|------------------|
| `m.find(k) == m.end()` | `!m.contains(k)` |
| `m.find(k) != m.end()` | `m.contains(k)` |
| `m.count(k)` | `m.contains(k)` |
| `!m.count(k)` | `!m.contains(k)` |
| `m.count(k) == 0` | `!m.contains(k)` |
| `m.count(k) != 1` | `!m.contains(k)` |
| `m.count(k) == 1` | `m.contains(k)` |
| `m.count(k) < 1` | `!m.contains(k)` |
| `m.count(k) > 0` | `m.contains(k)` |
| `m.count(k) != 0` | `m.contains(k)` |
> Note that `== 1`/`!= 1`/`< 1` only apply to simple [maps](https://en.cppreference.com/w/cpp/container/map/contains)/[sets](https://en.cppreference.com/w/cpp/container/set/contains) and had to be changed manually.
There are many other cases that could have been changed, but we've reverted most of those to reduce conflict with other open PRs.
-----
<details>
<summary>clang-tidy command on Mac</summary>
```bash
rm -rfd build && \
cmake -B build \
-DCMAKE_C_COMPILER="$(brew --prefix llvm)/bin/clang" \
-DCMAKE_CXX_COMPILER="$(brew --prefix llvm)/bin/clang++" \
-DCMAKE_OSX_SYSROOT="$(xcrun --show-sdk-path)" \
-DCMAKE_C_FLAGS="-target arm64-apple-macos11" \
-DCMAKE_CXX_FLAGS="-target arm64-apple-macos11" \
-DCMAKE_EXPORT_COMPILE_COMMANDS=ON -DBUILD_BENCH=ON -DBUILD_FUZZ_BINARY=ON -DBUILD_FOR_FUZZING=ON
"$(brew --prefix llvm)/bin/run-clang-tidy" -quiet -p build -j$(nproc) -checks='-*,readability-container-contains' | grep -v 'clang-tidy'
```
</details>
Note: this is a take 2 of https://github.com/bitcoin/bitcoin/pull/33094 with fewer contentious changes.
ACKs for top commit:
optout21:
reACK d9319b06cf82664d55f255387a348135fd7f91c7
sedited:
ACK d9319b06cf82664d55f255387a348135fd7f91c7
janb84:
re ACK d9319b06cf82664d55f255387a348135fd7f91c7
pablomartin4btc:
re-ACK d9319b06cf82664d55f255387a348135fd7f91c7
ryanofsky:
Code review ACK d9319b06cf82664d55f255387a348135fd7f91c7. I manually reviewed the full change, and it seems there are a lot of positive comments about this and no more very significant conflicts, so I will merge it shortly.
Tree-SHA512: e4415221676cfb88413ccc446e5f4369df7a55b6642347277667b973f515c3c8ee5bfa9ee0022479c8de945c89fbc9ff61bd8ba086e70f30298cbc1762610fe1
CCoinsViewCache::BatchWrite always returns true if called from a backed
cache, so just return void instead. Also return void from ::Sync and
::Flush.
This allows for dropping a FatalError condition and simplifying some
dead error handling code a bit.
Since we now no longer exercise the "error path" when returning from
`CCoinsView::BatchWrite`, make the method clear the cache instead. This
should only be exercised by tests and not change production behaviour.
This might slightly improve the coins_view fuzz test's ability to
generate better coverage.
Co-authored-by: l0rinc <pap.lorinc@gmail.com>
The changes made here were:
| From | To |
|-------------------|------------------|
| `m.count(k)` | `m.contains(k)` |
| `!m.count(k)` | `!m.contains(k)` |
| `m.count(k) == 0` | `!m.contains(k)` |
| `m.count(k) != 0` | `m.contains(k)` |
| `m.count(k) > 0` | `m.contains(k)` |
The commit contains the trivial, mechanical refactors where it doesn't matter if the container can have multiple elements or not
Co-authored-by: Jan B <608446+janb84@users.noreply.github.com>
A few temporary `CCoinsViewCache`'s are destructed right after the `Flush()`, therefore it is not necessary to call `ReallocateCache` to recreate them right before they're killed anyway.
* `Flush()` - retains existing functionality;
* `Flush(/*will_reuse_cache=*/false)` - skips destruction and reallocation of the parent cache since it will soon go out of scope anyway;
For the `will_reuse_cache` parameter we want to see exactly which ones will reallocate memory and which won't - since both can be valid usages.
This change was based on a subset of https://github.com/bitcoin/bitcoin/pull/28945.
Co-authored-by: Martin Ankerl <martin.ankerl@gmail.com>
Historically, the headers have been bumped some time after a file has
been touched. Do it now to avoid having to touch them again in the
future for that reason.
-BEGIN VERIFY SCRIPT-
sed -i --regexp-extended 's;( 20[0-2][0-9])(-20[0-2][0-9])? The Bitcoin Core developers;\1-present The Bitcoin Core developers;g' $( git show --pretty="" --name-only HEAD~0 )
-END VERIFY SCRIPT-
This can be reproduced according to the developer notes with something
like
( cd ./src/ && ../contrib/devtools/run-clang-tidy.py -p ../bld-cmake -fix -j $(nproc) )
Also, the header related changes were done manually.
The fuzzer goes through a sequence of operations that get applied to both a
real stack of CCoinsViewCache objects, and to simulation data, comparing
the two at the end.
