403e677c9 refactoring: IsInitialBlockDownload -> CChainState (James O'Beirne)
3ccbc376d refactoring: FlushStateToDisk -> CChainState (James O'Beirne)
4d6688603 refactoring: introduce ChainstateActive() (James O'Beirne)
d7c97edee move-only: make the CChainState interface public (James O'Beirne)
Pull request description:
This is part of the [assumeutxo project](https://github.com/bitcoin/bitcoin/projects/11):
Parent PR: #15606
Issue: #15605
Specification: https://github.com/jamesob/assumeutxo-docs/tree/2019-04-proposal/proposal
---
This changeset starts moving functionality intimately related to CChainState into methods. Parameterizing these functions by a particular CChainState is necessary for the use of multiple chainstates simultaneously (e.g. for asynchronous background validation).
In this change, we
- make the CChainState interface public - since other units will start to invoke its methods directly,
- introduce `::ChainstateActive()`, the CChainState equivalent for `::ChainActive()`,
- and move `IsInitialBlockDownload()` and `FlushStateToDisk()` into methods on CChainState.
Independent of assumeutxo, these changes better encapsulate chainstate behavior and allow easier use from a testing context.
There are more methods that we'll move in the future, but they require other substantial changes (i.e. moving ownership of the `CCoinsView*` hierarchy into CChainState) so we'll save them for future PRs.
---
The first move-only commit is most easily reviewed with `git diff ... --color-moved=dimmed_zebra`.
ACKs for commit 403e67:
Empact:
utACK 403e677c9e no need to address my nits herein
Sjors:
utACK 403e677
ryanofsky:
utACK 403e677c9ebbf9744733010e6b0c2d1b182ee850. Only change since previous review is removing global state comment as suggested.
MarcoFalke:
utACK 403e677c9e, though the diff still seems a bit bloated with some unnecessary changes in the second commit.
promag:
utACK 403e677 and rebased with current [master](c7cfd20a7).
Tree-SHA512: 6fcf260bb2dc201361170c0b4547405366f5f331fcc3a2bac29b24442814b7b244ca1b58aac5af716885f9a130c343b544590dff780da0bf835c7c5b3ccb2257
5d37c1bde0