fd6580e405 [refactor] txmempool: split epoch logic into class (Anthony Towns)
Pull request description:
Splits the epoch logic introduced in #17925 into a separate class.
Uses clang's thread safety annotations and encapsulates the data more strongly to reduce chances of bugs from API misuse.
ACKs for top commit:
jonatack:
ACK fd6580e405 using clang thread safety annotations looks like a very good idea, and the encapsulation this change adds should improve robustness (and possible unit test-ability) of the code. Verified that changing some of the locking duly provoked build-time warnings with Clang 9 on Debian and that small changes in the new `Epoch` class were covered by failing functional test assertions in `mempool_updatefromblock.py`, `mempool_resurrect.py`, and `mempool_reorg.py`
hebasto:
re-ACK fd6580e405, since my [previous](https://github.com/bitcoin/bitcoin/pull/18017#pullrequestreview-569619362) review:
Tree-SHA512: 7004623faa02b56639aa05ab7a078320a6d8d54ec62d8022876221e33f350f47df51ddff056c0de5be798f8eb39b5c03c2d3f035698555d70abc218e950f2f8c
b59f2787e5