From 1ebacb60f8f33d84b1f4894b5307df838d2b1abd Mon Sep 17 00:00:00 2001
From: Luke Dashjr <luke-jr+git@utopios.org>
Date: Mon, 21 Mar 2022 15:36:22 +0000
Subject: [PATCH] blockstorage: Add height_last to PruneLockInfo

---
 src/node/blockstorage.cpp | 12 ++++++++----
 src/node/blockstorage.h   |  6 ++++--
 2 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/src/node/blockstorage.cpp b/src/node/blockstorage.cpp
index 7464c9054d..810e8469be 100644
--- a/src/node/blockstorage.cpp
+++ b/src/node/blockstorage.cpp
@@ -31,6 +31,7 @@
 #include <util/batchpriority.h>
 #include <util/check.h>
 #include <util/fs.h>
+#include <util/overflow.h>
 #include <util/signalinterrupt.h>
 #include <util/strencodings.h>
 #include <util/translation.h>
@@ -283,10 +284,13 @@ bool BlockManager::DoPruneLocksForbidPruning(const CBlockFileInfo& block_file_in
         if (prune_lock.second.height_first == std::numeric_limits<int>::max()) continue;
         // Remove the buffer and one additional block here to get actual height that is outside of the buffer
         const unsigned int lock_height{(unsigned)std::max(1, prune_lock.second.height_first - PRUNE_LOCK_BUFFER - 1)};
-        if (block_file_info.nHeightLast > lock_height) {
-            LogPrint(BCLog::PRUNE, "%s limited pruning to height %d\n", prune_lock.first, lock_height);
-            return true;
-        }
+        const unsigned int lock_height_last{(unsigned)std::max(1, SaturatingAdd(prune_lock.second.height_last, PRUNE_LOCK_BUFFER))};
+        if (block_file_info.nHeightFirst > lock_height_last) continue;
+        if (block_file_info.nHeightLast <= lock_height) continue;
+        // TODO: Check each block within the file against the prune_lock range
+
+        LogPrint(BCLog::PRUNE, "%s limited pruning to height %d\n", prune_lock.first, lock_height);
+        return true;
     }
     return false;
 }
diff --git a/src/node/blockstorage.h b/src/node/blockstorage.h
index 35ba993aba..eacc9c6387 100644
--- a/src/node/blockstorage.h
+++ b/src/node/blockstorage.h
@@ -93,6 +93,7 @@ struct CBlockIndexHeightOnlyComparator {
 
 struct PruneLockInfo {
     int height_first{std::numeric_limits<int>::max()}; //! Height of earliest block that should be kept and not pruned
+    int height_last{std::numeric_limits<int>::max()}; //! Height of latest block that should be kept and not pruned
 };
 
 enum BlockfileType {
@@ -253,8 +254,9 @@ private:
     /**
      * Map from external index name to oldest block that must not be pruned.
      *
-     * @note Internally, only blocks at height (height_first - PRUNE_LOCK_BUFFER - 1) and
-     * below will be pruned, but callers should avoid assuming any particular buffer size.
+     * @note Internally, only blocks before height (height_first - PRUNE_LOCK_BUFFER - 1) and
+     * after height (height_last + PRUNE_LOCK_BUFFER) will be pruned, but callers should
+     * avoid assuming any particular buffer size.
      */
     std::unordered_map<std::string, PruneLockInfo> m_prune_locks GUARDED_BY(::cs_main);