2 files changed, 40 insertions, 27 deletions

diff --git a/src/interfaces/chain.cpp b/src/interfaces/chain.cpp
index 0b3cd08e22..cfaf79f709 100644
--- a/src/interfaces/chain.cpp
+++ b/src/interfaces/chain.cpp
@@ -38,6 +38,21 @@
 namespace interfaces {
 namespace {
 
+bool FillBlock(const CBlockIndex* index, const FoundBlock& block, UniqueLock<RecursiveMutex>& lock)
+{
+    if (!index) return false;
+    if (block.m_hash) *block.m_hash = index->GetBlockHash();
+    if (block.m_height) *block.m_height = index->nHeight;
+    if (block.m_time) *block.m_time = index->GetBlockTime();
+    if (block.m_max_time) *block.m_max_time = index->GetBlockTimeMax();
+    if (block.m_mtp_time) *block.m_mtp_time = index->GetMedianTimePast();
+    if (block.m_data) {
+        REVERSE_LOCK(lock);
+        if (!ReadBlockFromDisk(*block.m_data, index, Params().GetConsensus())) block.m_data->SetNull();
+    }
+    return true;
+}
+
 class LockImpl : public Chain::Lock, public UniqueLock<RecursiveMutex>
 {
     Optional<int> getHeight() override
@@ -247,26 +262,10 @@ public:
         std::unique_ptr<Chain::Lock> result = std::move(lock); // Temporary to avoid CWG 1579
         return result;
     }
-    bool findBlock(const uint256& hash, CBlock* block, int64_t* time, int64_t* time_max) override
+    bool findBlock(const uint256& hash, const FoundBlock& block) override
     {
-        CBlockIndex* index;
-        {
-            LOCK(cs_main);
-            index = LookupBlockIndex(hash);
-            if (!index) {
-                return false;
-            }
-            if (time) {
-                *time = index->GetBlockTime();
-            }
-            if (time_max) {
-                *time_max = index->GetBlockTimeMax();
-            }
-        }
-        if (block && !ReadBlockFromDisk(*block, index, Params().GetConsensus())) {
-            block->SetNull();
-        }
-        return true;
+        WAIT_LOCK(cs_main, lock);
+        return FillBlock(LookupBlockIndex(hash), block, lock);
     }
     void findCoins(std::map<COutPoint, Coin>& coins) override { return FindCoins(m_node, coins); }
     double guessVerificationProgress(const uint256& block_hash) override
diff --git a/src/interfaces/chain.h b/src/interfaces/chain.h
index e1bc9bbbf3..3778ab9a8b 100644
--- a/src/interfaces/chain.h
+++ b/src/interfaces/chain.h
@@ -30,6 +30,27 @@ namespace interfaces {
 class Handler;
 class Wallet;
 
+//! Helper for findBlock to selectively return pieces of block data.
+class FoundBlock
+{
+public:
+    FoundBlock& hash(uint256& hash) { m_hash = &hash; return *this; }
+    FoundBlock& height(int& height) { m_height = &height; return *this; }
+    FoundBlock& time(int64_t& time) { m_time = &time; return *this; }
+    FoundBlock& maxTime(int64_t& max_time) { m_max_time = &max_time; return *this; }
+    FoundBlock& mtpTime(int64_t& mtp_time) { m_mtp_time = &mtp_time; return *this; }
+    //! Read block data from disk. If the block exists but doesn't have data
+    //! (for example due to pruning), the CBlock variable will be set to null.
+    FoundBlock& data(CBlock& data) { m_data = &data; return *this; }
+
+    uint256* m_hash = nullptr;
+    int* m_height = nullptr;
+    int64_t* m_time = nullptr;
+    int64_t* m_max_time = nullptr;
+    int64_t* m_mtp_time = nullptr;
+    CBlock* m_data = nullptr;
+};
+
 //! Interface giving clients (wallet processes, maybe other analysis tools in
 //! the future) ability to access to the chain state, receive notifications,
 //! estimate fees, and submit transactions.
@@ -127,14 +148,7 @@ public:
 
     //! Return whether node has the block and optionally return block metadata
     //! or contents.
-    //!
-    //! If a block pointer is provided to retrieve the block contents, and the
-    //! block exists but doesn't have data (for example due to pruning), the
-    //! block will be empty and all fields set to null.
-    virtual bool findBlock(const uint256& hash,
-        CBlock* block = nullptr,
-        int64_t* time = nullptr,
-        int64_t* max_time = nullptr) = 0;
+    virtual bool findBlock(const uint256& hash, const FoundBlock& block={}) = 0;
 
     //! Look up unspent output information. Returns coins in the mempool and in
     //! the current chain UTXO set. Iterates through all the keys in the map and