From fa961141f7fc515fbb6fcb9d8417108034b256ce Mon Sep 17 00:00:00 2001
From: MarcoFalke <*~=`'#}+{/-|&$^_@721217.xyz>
Date: Tue, 3 Jan 2023 12:56:06 +0100
Subject: [PATCH 1/2] Add HashVerifier

It is similar to CHashVerifier, but HashVerifier does not need a
serialize type and version
---
 src/hash.h | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/src/hash.h b/src/hash.h
index b18a0312685..b2ef29fcdbd 100644
--- a/src/hash.h
+++ b/src/hash.h
@@ -6,6 +6,7 @@
 #ifndef BITCOIN_HASH_H
 #define BITCOIN_HASH_H
 
+#include <attributes.h>
 #include <crypto/common.h>
 #include <crypto/ripemd160.h>
 #include <crypto/sha256.h>
@@ -165,6 +166,39 @@ public:
 };
 
 /** Reads data from an underlying stream, while hashing the read data. */
+template <typename Source>
+class HashVerifier : public HashWriter
+{
+private:
+    Source& m_source;
+
+public:
+    explicit HashVerifier(Source& source LIFETIMEBOUND) : m_source{source} {}
+
+    void read(Span<std::byte> dst)
+    {
+        m_source.read(dst);
+        this->write(dst);
+    }
+
+    void ignore(size_t num_bytes)
+    {
+        std::byte data[1024];
+        while (num_bytes > 0) {
+            size_t now = std::min<size_t>(num_bytes, 1024);
+            read({data, now});
+            num_bytes -= now;
+        }
+    }
+
+    template <typename T>
+    HashVerifier<Source>& operator>>(T&& obj)
+    {
+        ::Unserialize(*this, obj);
+        return *this;
+    }
+};
+
 template<typename Source>
 class CHashVerifier : public CHashWriter
 {

From eeee61065fe165dcce9625f7cc4cfce9e432aafa Mon Sep 17 00:00:00 2001
From: MarcoFalke <*~=`'#}+{/-|&$^_@721217.xyz>
Date: Tue, 3 Jan 2023 13:03:19 +0100
Subject: [PATCH 2/2] Use AutoFile and HashVerifier where possible

---
 src/node/blockstorage.cpp | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/node/blockstorage.cpp b/src/node/blockstorage.cpp
index b8a57acf804..a81099a26c0 100644
--- a/src/node/blockstorage.cpp
+++ b/src/node/blockstorage.cpp
@@ -352,7 +352,7 @@ bool BlockManager::LoadBlockIndexDB(const Consensus::Params& consensus_params)
     }
     for (std::set<int>::iterator it = setBlkDataFiles.begin(); it != setBlkDataFiles.end(); it++) {
         FlatFilePos pos(*it, 0);
-        if (CAutoFile(OpenBlockFile(pos, true), SER_DISK, CLIENT_VERSION).IsNull()) {
+        if (AutoFile{OpenBlockFile(pos, true)}.IsNull()) {
             return false;
         }
     }
@@ -454,13 +454,13 @@ CBlockFileInfo* BlockManager::GetBlockFileInfo(size_t n)
 static bool UndoWriteToDisk(const CBlockUndo& blockundo, FlatFilePos& pos, const uint256& hashBlock, const CMessageHeader::MessageStartChars& messageStart)
 {
     // Open history file to append
-    CAutoFile fileout(OpenUndoFile(pos), SER_DISK, CLIENT_VERSION);
+    AutoFile fileout{OpenUndoFile(pos)};
     if (fileout.IsNull()) {
         return error("%s: OpenUndoFile failed", __func__);
     }
 
     // Write index header
-    unsigned int nSize = GetSerializeSize(blockundo, fileout.GetVersion());
+    unsigned int nSize = GetSerializeSize(blockundo, CLIENT_VERSION);
     fileout << messageStart << nSize;
 
     // Write undo data
@@ -489,14 +489,14 @@ bool UndoReadFromDisk(CBlockUndo& blockundo, const CBlockIndex* pindex)
     }
 
     // Open history file to read
-    CAutoFile filein(OpenUndoFile(pos, true), SER_DISK, CLIENT_VERSION);
+    AutoFile filein{OpenUndoFile(pos, true)};
     if (filein.IsNull()) {
         return error("%s: OpenUndoFile failed", __func__);
     }
 
     // Read block
     uint256 hashChecksum;
-    CHashVerifier<CAutoFile> verifier(&filein); // We need a CHashVerifier as reserializing may lose data
+    HashVerifier verifier{filein}; // Use HashVerifier as reserializing may lose data, c.f. commit d342424301013ec47dc146a4beb49d5c9319d80a
     try {
         verifier << pindex->pprev->GetBlockHash();
         verifier >> blockundo;
@@ -768,7 +768,7 @@ bool ReadRawBlockFromDisk(std::vector<uint8_t>& block, const FlatFilePos& pos, c
 {
     FlatFilePos hpos = pos;
     hpos.nPos -= 8; // Seek back 8 bytes for meta header
-    CAutoFile filein(OpenBlockFile(hpos, true), SER_DISK, CLIENT_VERSION);
+    AutoFile filein{OpenBlockFile(hpos, true)};
     if (filein.IsNull()) {
         return error("%s: OpenBlockFile failed for %s", __func__, pos.ToString());
     }