refactor, blockstorage: Generalize GetFirstStoredBlock

GetFirstStoredBlock is generalized to check for any data status with a
status mask that needs to be passed as a parameter. To reflect this the
function is also renamed to GetFirstBlock.

Co-authored-by: stickies-v <stickies-v@protonmail.com>

2 files changed, 31 insertions, 8 deletions

diff --git a/src/node/blockstorage.cpp b/src/node/blockstorage.cpp
index 576c07a833..6dbc111eb6 100644
--- a/src/node/blockstorage.cpp
+++ b/src/node/blockstorage.cpp
@@ -595,12 +595,12 @@ bool BlockManager::IsBlockPruned(const CBlockIndex& block)
     return m_have_pruned && !(block.nStatus & BLOCK_HAVE_DATA) && (block.nTx > 0);
 }
 
-const CBlockIndex* BlockManager::GetFirstStoredBlock(const CBlockIndex& upper_block, const CBlockIndex* lower_block)
+const CBlockIndex* BlockManager::GetFirstBlock(const CBlockIndex& upper_block, uint32_t status_mask, const CBlockIndex* lower_block) const
 {
     AssertLockHeld(::cs_main);
     const CBlockIndex* last_block = &upper_block;
-    assert(last_block->nStatus & BLOCK_HAVE_DATA); // 'upper_block' must have data
-    while (last_block->pprev && (last_block->pprev->nStatus & BLOCK_HAVE_DATA)) {
+    assert((last_block->nStatus & status_mask) == status_mask); // 'upper_block' must satisfy the status mask
+    while (last_block->pprev && ((last_block->pprev->nStatus & status_mask) == status_mask)) {
         if (lower_block) {
             // Return if we reached the lower_block
             if (last_block == lower_block) return lower_block;
@@ -617,7 +617,7 @@ const CBlockIndex* BlockManager::GetFirstStoredBlock(const CBlockIndex& upper_bl
 bool BlockManager::CheckBlockDataAvailability(const CBlockIndex& upper_block, const CBlockIndex& lower_block)
 {
     if (!(upper_block.nStatus & BLOCK_HAVE_DATA)) return false;
-    return GetFirstStoredBlock(upper_block, &lower_block) == &lower_block;
+    return GetFirstBlock(upper_block, BLOCK_HAVE_DATA, &lower_block) == &lower_block;
 }
 
 // If we're using -prune with -reindex, then delete block files that will be ignored by the
diff --git a/src/node/blockstorage.h b/src/node/blockstorage.h
index ce514cc645..d1e46fde2b 100644
--- a/src/node/blockstorage.h
+++ b/src/node/blockstorage.h
@@ -335,10 +335,33 @@ public:
     //! (part of the same chain).
     bool CheckBlockDataAvailability(const CBlockIndex& upper_block LIFETIMEBOUND, const CBlockIndex& lower_block LIFETIMEBOUND) EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
 
-    //! Find the first stored ancestor of start_block immediately after the last
-    //! pruned ancestor. Return value will never be null. Caller is responsible
-    //! for ensuring that start_block has data is not pruned.
-    const CBlockIndex* GetFirstStoredBlock(const CBlockIndex& start_block LIFETIMEBOUND, const CBlockIndex* lower_block=nullptr) EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
+    /**
+     * @brief Returns the earliest block with specified `status_mask` flags set after
+     * the latest block _not_ having those flags.
+     *
+     * This function starts from `upper_block`, which must have all
+     * `status_mask` flags set, and iterates backwards through its ancestors. It
+     * continues as long as each block has all `status_mask` flags set, until
+     * reaching the oldest ancestor or `lower_block`.
+     *
+     * @pre `upper_block` must have all `status_mask` flags set.
+     * @pre `lower_block` must be null or an ancestor of `upper_block`
+     *
+     * @param upper_block The starting block for the search, which must have all
+     *                    `status_mask` flags set.
+     * @param status_mask Bitmask specifying required status flags.
+     * @param lower_block The earliest possible block to return. If null, the
+     *                    search can extend to the genesis block.
+     *
+     * @return A non-null pointer to the earliest block between `upper_block`
+     *         and `lower_block`, inclusive, such that every block between the
+     *         returned block and `upper_block` has `status_mask` flags set.
+     */
+    const CBlockIndex* GetFirstBlock(
+        const CBlockIndex& upper_block LIFETIMEBOUND,
+        uint32_t status_mask,
+        const CBlockIndex* lower_block = nullptr
+    ) const EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
 
     /** True if any block files have ever been pruned. */
     bool m_have_pruned = false;