Merge bitcoin/bitcoin#25487: [kernel 3b/n] Decouple `{Dump,Load}Mempool` from `ArgsManager`

cb3e9a1e3f8d72daaa361fc45dd853775e754b9d Move {Load,Dump}Mempool to kernel namespace (Carl Dong)
aa306765419f7dbea12b12e15553039835ba0e4d Move DEFAULT_PERSIST_MEMPOOL out of libbitcoinkernel (Carl Dong)
06b88ffb8ae7f2b2a93a32908cd80e77fafd270c LoadMempool: Pass in load_path, stop using gArgs (Carl Dong)
b857ac60d9a0433036519c26675378bbf56a1de1 test/fuzz: Invoke LoadMempool via CChainState (Carl Dong)
b3267258b052557fc136b9a4dcb754afb9219470 Move FopenFn to fsbridge namespace (Carl Dong)
ae1e8e37567fa603a5977d7d05105c682dd3f7db mempool: Use NodeClock+friends for LoadMempool (Carl Dong)
f9e8e5719f28d84f68f7d75e26c8e7fccac8e7d3 mempool: Improve comments for [GS]etLoadTried (Carl Dong)
813962da0b17b918941c6849996845e35d84a451 scripted-diff: Rename m_is_loaded -> m_load_tried (Carl Dong)
413f4bb52b72e082ad8716664ede48352b8e7e5a DumpMempool: Pass in dump_path, stop using gArgs (Carl Dong)
bd4407817e523e3c5b347bc6be25ed007cb27034 DumpMempool: Use std::chrono instead of weird int64_t arthmetics (Carl Dong)
c84390b741ab7b61c9f702d8b447c8cadc1257c8 test/mempool_persist: Test manual savemempool when -persistmempool=0 (Carl Dong)

Pull request description:

  This is part of the `libbitcoinkernel` project: #24303, https://github.com/bitcoin/bitcoin/projects/18

  -----

  This PR moves `{Dump,Load}Mempool` into its own `kernel/mempool_persist` module and introduces `ArgsManager` `node::` helpers in `node/mempool_persist_args`to remove the scattered calls to `GetBoolArg("-persistmempool", DEFAULT_PERSIST_MEMPOOL)`.

  More context can be gleaned from the commit messages.

  -----

  One thing I was reflecting on as I wrote this was that in the long run, I think we should probably invert the validation <-> mempool relationship. Instead of mempool not depending on validation, it might make more sense to have validation not depend on mempool. Not super urgent since `libbitcoinkernel` will include both validation and mempool, but perhaps something for the future.

ACKs for top commit:
  glozow:
    re ACK cb3e9a1e3f8d72daaa361fc45dd853775e754b9d via `git range-diff 7ae032e...cb3e9a1`
  MarcoFalke:
    ACK cb3e9a1e3f 🔒
  ryanofsky:
    Code review ACK cb3e9a1e3f8d72daaa361fc45dd853775e754b9d

Tree-SHA512: 979d7237c3abb5a1dd9b5ad3dbf3b954f906a6d8320ed7b923557f41a4472deccae3e8a6bca0018c8e7a3c4a93afecc502acd1e26756f2054f157f1c0edd939d

1 files changed, 1 insertions, 11 deletions

diff --git a/src/validation.h b/src/validation.h
index aa9fcf9f2d..a21d9e3a28 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -68,8 +68,6 @@ static const bool DEFAULT_CHECKPOINTS_ENABLED = true;
 static const bool DEFAULT_TXINDEX = false;
 static constexpr bool DEFAULT_COINSTATSINDEX{false};
 static const char* const DEFAULT_BLOCKFILTERINDEX = "0";
-/** Default for -persistmempool */
-static const bool DEFAULT_PERSIST_MEMPOOL = true;
 /** Default for -stopatheight */
 static const int DEFAULT_STOPATHEIGHT = 0;
 /** Block files containing a block-height within MIN_BLOCKS_TO_KEEP of ActiveChain().Tip() will not be pruned. */
@@ -679,7 +677,7 @@ public:
     void CheckBlockIndex();
 
     /** Load the persisted mempool from disk */
-    void LoadMempool(const ArgsManager& args);
+    void LoadMempool(const fs::path& load_path, fsbridge::FopenFn mockable_fopen_function = fsbridge::fopen);
 
     /** Update the chain tip based on database information, i.e. CoinsTip()'s best block. */
     bool LoadChainTip() EXCLUSIVE_LOCKS_REQUIRED(cs_main);
@@ -1014,14 +1012,6 @@ bool DeploymentEnabled(const ChainstateManager& chainman, DEP dep)
     return DeploymentEnabled(chainman.GetConsensus(), dep);
 }
 
-using FopenFn = std::function<FILE*(const fs::path&, const char*)>;
-
-/** Dump the mempool to disk. */
-bool DumpMempool(const CTxMemPool& pool, FopenFn mockable_fopen_function = fsbridge::fopen, bool skip_file_commit = false);
-
-/** Load the mempool from disk. */
-bool LoadMempool(CTxMemPool& pool, CChainState& active_chainstate, FopenFn mockable_fopen_function = fsbridge::fopen);
-
 /**
  * Return the expected assumeutxo value for a given height, if one exists.
  *