[indexes] Add compact block filter headers cache

Cache block filter headers at heights of multiples of 1000 in memory.

Block filter headers at height 1000x are checkpointed, and will be the
most frequently requested. Cache them in memory to avoid costly disk
reads.

1 files changed, 2 insertions, 4 deletions

diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index 1df1fab59d..61a254db7d 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -129,8 +129,6 @@ static constexpr unsigned int INVENTORY_BROADCAST_MAX = 7 * INVENTORY_BROADCAST_
 static constexpr unsigned int AVG_FEEFILTER_BROADCAST_INTERVAL = 10 * 60;
 /** Maximum feefilter broadcast delay after significant change. */
 static constexpr unsigned int MAX_FEEFILTER_CHANGE_DELAY = 5 * 60;
-/** Interval between compact filter checkpoints. See BIP 157. */
-static constexpr int CFCHECKPT_INTERVAL = 1000;
 
 struct COrphanTx {
     // When modifying, adapt the copy of this definition in tests/DoS_tests.
@@ -1990,7 +1988,7 @@ static bool PrepareBlockFilterRequest(CNode* pfrom, const CChainParams& chain_pa
                                       BlockFilterType filter_type,
                                       const uint256& stop_hash,
                                       const CBlockIndex*& stop_index,
-                                      const BlockFilterIndex*& filter_index)
+                                      BlockFilterIndex*& filter_index)
 {
     const bool supported_filter_type =
         (filter_type == BlockFilterType::BASIC &&
@@ -2045,7 +2043,7 @@ static void ProcessGetCFCheckPt(CNode* pfrom, CDataStream& vRecv, const CChainPa
     const BlockFilterType filter_type = static_cast<BlockFilterType>(filter_type_ser);
 
     const CBlockIndex* stop_index;
-    const BlockFilterIndex* filter_index;
+    BlockFilterIndex* filter_index;
     if (!PrepareBlockFilterRequest(pfrom, chain_params, filter_type, stop_hash,
                                    stop_index, filter_index)) {
         return;