Merge #15655: Resolve the checkpoints <-> validation circular dependency

418d3230f8 Resolve the checkpoints <-> validation CD. (251)

Pull request description:

  This pull request attempts to resolve the `checkpoints -> validation -> checkpoints` circular dependency.

  The circular dependency is resolved by moving the `CheckPoints::GetLastCheckpoint(const CCheckpointData& data)` function to `validation.cpp` where it used exclusively by the private function `ContextualCheckBlockHeader(const CBlockHeader& block, CValidationState& state, const CChainParams& params, const CBlockIndex* pindexPrev, int64_t nAdjustedTime)`.

ACKs for commit 418d32:
  promag:
    utACK 418d323, only `GetLastCheckpoint` usage is in `validation.cpp` and so makes sense to move it there.
  practicalswift:
    utACK 418d3230f86f77dde6e817f502baff8a54b707fa
  MarcoFalke:
    utACK 418d3230f86f77dde6e817f502baff8a54b707fa
  sipa:
    utACK 418d3230f86f77dde6e817f502baff8a54b707fa

Tree-SHA512: 03c3556bc192e65f5e3fa76fd545d4ee7d63d3fb06b132f7a1fa6131aa21ddd2e5b2d19e2222dfe524f422daaca30efde219bed188db8c74ff4b088876b5bc16

1 files changed, 0 insertions, 32 deletions

diff --git a/src/checkpoints.cpp b/src/checkpoints.cpp
deleted file mode 100644
index ad5edfeb39..0000000000
--- a/src/checkpoints.cpp
+++ /dev/null
@@ -1,32 +0,0 @@
-// Copyright (c) 2009-2018 The Bitcoin Core developers
-// Distributed under the MIT software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
-
-#include <checkpoints.h>
-
-#include <chain.h>
-#include <chainparams.h>
-#include <reverse_iterator.h>
-#include <validation.h>
-
-#include <stdint.h>
-
-
-namespace Checkpoints {
-
-    CBlockIndex* GetLastCheckpoint(const CCheckpointData& data)
-    {
-        const MapCheckpoints& checkpoints = data.mapCheckpoints;
-
-        for (const MapCheckpoints::value_type& i : reverse_iterate(checkpoints))
-        {
-            const uint256& hash = i.second;
-            CBlockIndex* pindex = LookupBlockIndex(hash);
-            if (pindex) {
-                return pindex;
-            }
-        }
-        return nullptr;
-    }
-
-} // namespace Checkpoints