node/chainstate: Remove do/while loop

I strongly recommend reviewing with the following git-diff flags:
  --ignore-space-change

1 files changed, 114 insertions, 115 deletions

diff --git a/src/node/chainstate.cpp b/src/node/chainstate.cpp
index 86de364ca7..8cc523fdd5 100644
--- a/src/node/chainstate.cpp
+++ b/src/node/chainstate.cpp
@@ -28,139 +28,138 @@ std::optional<ChainstateLoadingError> LoadChainstate(bool fReset,
         return fReset || fReindexChainState || chainstate->CoinsTip().GetBestBlock().IsNull();
     };
 
-    do {
-        try {
-            LOCK(cs_main);
-            chainman.InitializeChainstate(mempool);
-            chainman.m_total_coinstip_cache = nCoinCacheUsage;
-            chainman.m_total_coinsdb_cache = nCoinDBCache;
-
-            UnloadBlockIndex(mempool, chainman);
-
-            auto& pblocktree{chainman.m_blockman.m_block_tree_db};
-            // new CBlockTreeDB tries to delete the existing file, which
-            // fails if it's still open from the previous loop. Close it first:
-            pblocktree.reset();
-            pblocktree.reset(new CBlockTreeDB(nBlockTreeDBCache, false, fReset));
-
-            if (fReset) {
-                pblocktree->WriteReindexing(true);
-                //If we're reindexing in prune mode, wipe away unusable block files and all undo data files
-                if (fPruneMode)
-                    CleanupBlockRevFiles();
-            }
+    try {
+        LOCK(cs_main);
+        chainman.InitializeChainstate(mempool);
+        chainman.m_total_coinstip_cache = nCoinCacheUsage;
+        chainman.m_total_coinsdb_cache = nCoinDBCache;
+
+        UnloadBlockIndex(mempool, chainman);
+
+        auto& pblocktree{chainman.m_blockman.m_block_tree_db};
+        // new CBlockTreeDB tries to delete the existing file, which
+        // fails if it's still open from the previous loop. Close it first:
+        pblocktree.reset();
+        pblocktree.reset(new CBlockTreeDB(nBlockTreeDBCache, false, fReset));
+
+        if (fReset) {
+            pblocktree->WriteReindexing(true);
+            //If we're reindexing in prune mode, wipe away unusable block files and all undo data files
+            if (fPruneMode)
+                CleanupBlockRevFiles();
+        }
+
+        if (ShutdownRequested()) return ChainstateLoadingError::SHUTDOWN_PROBED;
 
+        // LoadBlockIndex will load fHavePruned if we've ever removed a
+        // block file from disk.
+        // Note that it also sets fReindex based on the disk flag!
+        // From here on out fReindex and fReset mean something different!
+        if (!chainman.LoadBlockIndex()) {
             if (ShutdownRequested()) return ChainstateLoadingError::SHUTDOWN_PROBED;
+            return ChainstateLoadingError::ERROR_LOADING_BLOCK_DB;
+        }
 
-            // LoadBlockIndex will load fHavePruned if we've ever removed a
-            // block file from disk.
-            // Note that it also sets fReindex based on the disk flag!
-            // From here on out fReindex and fReset mean something different!
-            if (!chainman.LoadBlockIndex()) {
-                if (ShutdownRequested()) return ChainstateLoadingError::SHUTDOWN_PROBED;
-                return ChainstateLoadingError::ERROR_LOADING_BLOCK_DB;
-            }
+        if (!chainman.BlockIndex().empty() &&
+                !chainman.m_blockman.LookupBlockIndex(chainparams.GetConsensus().hashGenesisBlock)) {
+            return ChainstateLoadingError::ERROR_BAD_GENESIS_BLOCK;
+        }
 
-            if (!chainman.BlockIndex().empty() &&
-                    !chainman.m_blockman.LookupBlockIndex(chainparams.GetConsensus().hashGenesisBlock)) {
-                return ChainstateLoadingError::ERROR_BAD_GENESIS_BLOCK;
-            }
+        // Check for changed -prune state.  What we are concerned about is a user who has pruned blocks
+        // in the past, but is now trying to run unpruned.
+        if (fHavePruned && !fPruneMode) {
+            return ChainstateLoadingError::ERROR_PRUNED_NEEDS_REINDEX;
+        }
+
+        // At this point blocktree args are consistent with what's on disk.
+        // If we're not mid-reindex (based on disk + args), add a genesis block on disk
+        // (otherwise we use the one already on disk).
+        // This is called again in ThreadImport after the reindex completes.
+        if (!fReindex && !chainman.ActiveChainstate().LoadGenesisBlock()) {
+            return ChainstateLoadingError::ERROR_LOAD_GENESIS_BLOCK_FAILED;
+        }
 
-            // Check for changed -prune state.  What we are concerned about is a user who has pruned blocks
-            // in the past, but is now trying to run unpruned.
-            if (fHavePruned && !fPruneMode) {
-                return ChainstateLoadingError::ERROR_PRUNED_NEEDS_REINDEX;
+        // At this point we're either in reindex or we've loaded a useful
+        // block tree into BlockIndex()!
+
+        for (CChainState* chainstate : chainman.GetAll()) {
+            chainstate->InitCoinsDB(
+                /* cache_size_bytes */ nCoinDBCache,
+                /* in_memory */ false,
+                /* should_wipe */ fReset || fReindexChainState);
+
+            chainstate->CoinsErrorCatcher().AddReadErrCallback([]() {
+                uiInterface.ThreadSafeMessageBox(
+                    _("Error reading from database, shutting down."),
+                    "", CClientUIInterface::MSG_ERROR);
+            });
+
+            // If necessary, upgrade from older database format.
+            // This is a no-op if we cleared the coinsviewdb with -reindex or -reindex-chainstate
+            if (!chainstate->CoinsDB().Upgrade()) {
+                return ChainstateLoadingError::ERROR_CHAINSTATE_UPGRADE_FAILED;
             }
 
-            // At this point blocktree args are consistent with what's on disk.
-            // If we're not mid-reindex (based on disk + args), add a genesis block on disk
-            // (otherwise we use the one already on disk).
-            // This is called again in ThreadImport after the reindex completes.
-            if (!fReindex && !chainman.ActiveChainstate().LoadGenesisBlock()) {
-                return ChainstateLoadingError::ERROR_LOAD_GENESIS_BLOCK_FAILED;
+            // ReplayBlocks is a no-op if we cleared the coinsviewdb with -reindex or -reindex-chainstate
+            if (!chainstate->ReplayBlocks()) {
+                return ChainstateLoadingError::ERROR_REPLAYBLOCKS_FAILED;
             }
 
-            // At this point we're either in reindex or we've loaded a useful
-            // block tree into BlockIndex()!
-
-            for (CChainState* chainstate : chainman.GetAll()) {
-                chainstate->InitCoinsDB(
-                    /* cache_size_bytes */ nCoinDBCache,
-                    /* in_memory */ false,
-                    /* should_wipe */ fReset || fReindexChainState);
-
-                chainstate->CoinsErrorCatcher().AddReadErrCallback([]() {
-                    uiInterface.ThreadSafeMessageBox(
-                        _("Error reading from database, shutting down."),
-                        "", CClientUIInterface::MSG_ERROR);
-                });
-
-                // If necessary, upgrade from older database format.
-                // This is a no-op if we cleared the coinsviewdb with -reindex or -reindex-chainstate
-                if (!chainstate->CoinsDB().Upgrade()) {
-                    return ChainstateLoadingError::ERROR_CHAINSTATE_UPGRADE_FAILED;
-                }
+            // The on-disk coinsdb is now in a good state, create the cache
+            chainstate->InitCoinsCache(nCoinCacheUsage);
+            assert(chainstate->CanFlushToDisk());
 
-                // ReplayBlocks is a no-op if we cleared the coinsviewdb with -reindex or -reindex-chainstate
-                if (!chainstate->ReplayBlocks()) {
-                    return ChainstateLoadingError::ERROR_REPLAYBLOCKS_FAILED;
+            if (!is_coinsview_empty(chainstate)) {
+                // LoadChainTip initializes the chain based on CoinsTip()'s best block
+                if (!chainstate->LoadChainTip()) {
+                    return ChainstateLoadingError::ERROR_LOADCHAINTIP_FAILED;
                 }
+                assert(chainstate->m_chain.Tip() != nullptr);
+            }
+        }
+    } catch (const std::exception& e) {
+        LogPrintf("%s\n", e.what());
+        return ChainstateLoadingError::ERROR_GENERIC_BLOCKDB_OPEN_FAILED;
+    }
+
+    if (!fReset) {
+        LOCK(cs_main);
+        auto chainstates{chainman.GetAll()};
+        if (std::any_of(chainstates.begin(), chainstates.end(),
+                        [](const CChainState* cs) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { return cs->NeedsRedownload(); })) {
+            return ChainstateLoadingError::ERROR_BLOCKS_WITNESS_INSUFFICIENTLY_VALIDATED;
+        }
+    }
 
-                // The on-disk coinsdb is now in a good state, create the cache
-                chainstate->InitCoinsCache(nCoinCacheUsage);
-                assert(chainstate->CanFlushToDisk());
+    try {
+        LOCK(cs_main);
 
-                if (!is_coinsview_empty(chainstate)) {
-                    // LoadChainTip initializes the chain based on CoinsTip()'s best block
-                    if (!chainstate->LoadChainTip()) {
-                        return ChainstateLoadingError::ERROR_LOADCHAINTIP_FAILED;
-                    }
-                    assert(chainstate->m_chain.Tip() != nullptr);
+        for (CChainState* chainstate : chainman.GetAll()) {
+            if (!is_coinsview_empty(chainstate)) {
+                uiInterface.InitMessage(_("Verifying blocks…").translated);
+                if (fHavePruned && check_blocks > MIN_BLOCKS_TO_KEEP) {
+                    LogPrintf("Prune: pruned datadir may not have more than %d blocks; only checking available blocks\n",
+                        MIN_BLOCKS_TO_KEEP);
                 }
-            }
-        } catch (const std::exception& e) {
-            LogPrintf("%s\n", e.what());
-            return ChainstateLoadingError::ERROR_GENERIC_BLOCKDB_OPEN_FAILED;
-        }
 
-        if (!fReset) {
-            LOCK(cs_main);
-            auto chainstates{chainman.GetAll()};
-            if (std::any_of(chainstates.begin(), chainstates.end(),
-                            [](const CChainState* cs) EXCLUSIVE_LOCKS_REQUIRED(cs_main) { return cs->NeedsRedownload(); })) {
-                return ChainstateLoadingError::ERROR_BLOCKS_WITNESS_INSUFFICIENTLY_VALIDATED;
-            }
-        }
+                const CBlockIndex* tip = chainstate->m_chain.Tip();
+                RPCNotifyBlockChange(tip);
+                if (tip && tip->nTime > GetTime() + MAX_FUTURE_BLOCK_TIME) {
+                    return ChainstateLoadingError::ERROR_BLOCK_FROM_FUTURE;
+                }
 
-        try {
-            LOCK(cs_main);
-
-            for (CChainState* chainstate : chainman.GetAll()) {
-                if (!is_coinsview_empty(chainstate)) {
-                    uiInterface.InitMessage(_("Verifying blocks…").translated);
-                    if (fHavePruned && check_blocks > MIN_BLOCKS_TO_KEEP) {
-                        LogPrintf("Prune: pruned datadir may not have more than %d blocks; only checking available blocks\n",
-                            MIN_BLOCKS_TO_KEEP);
-                    }
-
-                    const CBlockIndex* tip = chainstate->m_chain.Tip();
-                    RPCNotifyBlockChange(tip);
-                    if (tip && tip->nTime > GetTime() + MAX_FUTURE_BLOCK_TIME) {
-                        return ChainstateLoadingError::ERROR_BLOCK_FROM_FUTURE;
-                    }
-
-                    if (!CVerifyDB().VerifyDB(
-                            *chainstate, chainparams, chainstate->CoinsDB(),
-                            check_level,
-                            check_blocks)) {
-                        return ChainstateLoadingError::ERROR_CORRUPTED_BLOCK_DB;
-                    }
+                if (!CVerifyDB().VerifyDB(
+                        *chainstate, chainparams, chainstate->CoinsDB(),
+                        check_level,
+                        check_blocks)) {
+                    return ChainstateLoadingError::ERROR_CORRUPTED_BLOCK_DB;
                 }
             }
-        } catch (const std::exception& e) {
-            LogPrintf("%s\n", e.what());
-            return ChainstateLoadingError::ERROR_GENERIC_BLOCKDB_OPEN_FAILED;
         }
-    } while(false);
+    } catch (const std::exception& e) {
+        LogPrintf("%s\n", e.what());
+        return ChainstateLoadingError::ERROR_GENERIC_BLOCKDB_OPEN_FAILED;
+    }
+
     return std::nullopt;
 }