Merge #15976: refactor: move methods under CChainState (pt. 1)

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 https://github.com/bitcoin/bitcoin/pull/15976/commits/403e677c9ebbf9744733010e6b0c2d1b182ee850 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

1 files changed, 8 insertions, 8 deletions

diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index a3b865a69e..3d0a9b192d 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -1240,7 +1240,7 @@ void PeerLogicValidation::BlockChecked(const CBlock& block, const CValidationSta
     //    the tip yet so we have no way to check this directly here. Instead we
     //    just check that there are currently no other blocks in flight.
     else if (state.IsValid() &&
-             !IsInitialBlockDownload() &&
+             !::ChainstateActive().IsInitialBlockDownload() &&
              mapBlocksInFlight.count(hash) == mapBlocksInFlight.size()) {
         if (it != mapBlockSource.end()) {
             MaybeSetPeerAsAnnouncingHeaderAndIDs(it->second.first, connman);
@@ -1728,7 +1728,7 @@ bool static ProcessHeadersMessage(CNode *pfrom, CConnman *connman, const std::ve
         }
         // If we're in IBD, we want outbound peers that will serve us a useful
         // chain. Disconnect peers that are on chains with insufficient work.
-        if (IsInitialBlockDownload() && nCount != MAX_HEADERS_RESULTS) {
+        if (::ChainstateActive().IsInitialBlockDownload() && nCount != MAX_HEADERS_RESULTS) {
             // When nCount < MAX_HEADERS_RESULTS, we know we have no more
             // headers to fetch from this peer.
             if (nodestate->pindexBestKnownBlock && nodestate->pindexBestKnownBlock->nChainWork < nMinimumChainWork) {
@@ -1994,7 +1994,7 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr
         if (!pfrom->fInbound)
         {
             // Advertise our address
-            if (fListen && !IsInitialBlockDownload())
+            if (fListen && !::ChainstateActive().IsInitialBlockDownload())
             {
                 CAddress addr = GetLocalAddress(&pfrom->addr, pfrom->GetLocalServices());
                 FastRandomContext insecure_rand;
@@ -2229,7 +2229,7 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr
                 pfrom->AddInventoryKnown(inv);
                 if (fBlocksOnly) {
                     LogPrint(BCLog::NET, "transaction (%s) inv sent in violation of protocol peer=%d\n", inv.hash.ToString(), pfrom->GetId());
-                } else if (!fAlreadyHave && !fImporting && !fReindex && !IsInitialBlockDownload()) {
+                } else if (!fAlreadyHave && !fImporting && !fReindex && !::ChainstateActive().IsInitialBlockDownload()) {
                     RequestTx(State(pfrom->GetId()), inv.hash, nNow);
                 }
             }
@@ -2387,7 +2387,7 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr
         }
 
         LOCK(cs_main);
-        if (IsInitialBlockDownload() && !pfrom->fWhitelisted) {
+        if (::ChainstateActive().IsInitialBlockDownload() && !pfrom->fWhitelisted) {
             LogPrint(BCLog::NET, "Ignoring getheaders from peer=%d because node is in initial block download\n", pfrom->GetId());
             return true;
         }
@@ -2609,7 +2609,7 @@ bool static ProcessMessage(CNode* pfrom, const std::string& strCommand, CDataStr
 
         if (!LookupBlockIndex(cmpctblock.header.hashPrevBlock)) {
             // Doesn't connect (or is genesis), instead of DoSing in AcceptBlockHeader, request deeper headers
-            if (!IsInitialBlockDownload())
+            if (!::ChainstateActive().IsInitialBlockDownload())
                 connman->PushMessage(pfrom, msgMaker.Make(NetMsgType::GETHEADERS, ::ChainActive().GetLocator(pindexBestHeader), uint256()));
             return true;
         }
@@ -3524,7 +3524,7 @@ bool PeerLogicValidation::SendMessages(CNode* pto)
 
         // Address refresh broadcast
         int64_t nNow = GetTimeMicros();
-        if (!IsInitialBlockDownload() && pto->nNextLocalAddrSend < nNow) {
+        if (!::ChainstateActive().IsInitialBlockDownload() && pto->nNextLocalAddrSend < nNow) {
             AdvertiseLocal(pto);
             pto->nNextLocalAddrSend = PoissonNextSend(nNow, AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL);
         }
@@ -3925,7 +3925,7 @@ bool PeerLogicValidation::SendMessages(CNode* pto)
         // Message: getdata (blocks)
         //
         std::vector<CInv> vGetData;
-        if (!pto->fClient && ((fFetch && !pto->m_limited_node) || !IsInitialBlockDownload()) && state.nBlocksInFlight < MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
+        if (!pto->fClient && ((fFetch && !pto->m_limited_node) || !::ChainstateActive().IsInitialBlockDownload()) && state.nBlocksInFlight < MAX_BLOCKS_IN_TRANSIT_PER_PEER) {
             std::vector<const CBlockIndex*> vToDownload;
             NodeId staller = -1;
             FindNextBlocksToDownload(pto->GetId(), MAX_BLOCKS_IN_TRANSIT_PER_PEER - state.nBlocksInFlight, vToDownload, staller, consensusParams);