refactor: Add interfaces::FoundBlock class to selectively return block data

FoundBlock class allows interfaces::Chain::findBlock to return more block
information without having lots of optional output parameters. FoundBlock class
is also used by other chain methods in upcoming commits.

There is mostly no change in behavior. Only exception is
CWallet::RescanFromTime now throwing NonFatalCheckError instead of
std::logic_error.

1 files changed, 18 insertions, 19 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