validate oplog before opening - if invalid, warn and wipe oplog (#153)

2 files changed, 13 insertions, 2 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 21bff4613..02d0201c2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,7 @@
 ##
 - Bugfix: Fix race condition in zenserver during batched fetch of small cache chunks (<=1024b) resulting in missing rawhash/rawsize in the response. UE-223703
 - Improvement: Don't add batch overhead if we are only going to put once cache value in a request
+- Improvement: Validate oplog log file and wipe state if it is corrupt before attempting to open
 
 ## 5.5.6
 - Bugfix: Make sure `noexcept` functions does not leak exceptions via ASSERT statements which causes crash via abort
diff --git a/src/zenserver/projectstore/projectstore.cpp b/src/zenserver/projectstore/projectstore.cpp
index d5570e8d4..b0d2554d6 100644
--- a/src/zenserver/projectstore/projectstore.cpp
+++ b/src/zenserver/projectstore/projectstore.cpp
@@ -351,6 +351,8 @@ struct ProjectStore::OplogStorage : public RefCounted
 	{
 		return std::filesystem::exists(GetLogPath(BasePath)) && std::filesystem::exists(GetBlobsPath(BasePath));
 	}
+	[[nodiscard]] bool		  IsValid() const { return IsValid(m_OplogStoragePath); }
+	[[nodiscard]] static bool IsValid(const std::filesystem::path& BasePath) { return TCasLogFile<OplogEntry>::IsValid(BasePath); }
 
 	static bool Delete(const std::filesystem::path& BasePath) { return DeleteDirectories(BasePath); }
 
@@ -941,8 +943,16 @@ ProjectStore::Oplog::Oplog(std::string_view				Id,
 {
 	using namespace std::literals;
 
-	m_Storage			   = new OplogStorage(this, m_BasePath);
-	const bool StoreExists = m_Storage->Exists();
+	m_Storage		 = new OplogStorage(this, m_BasePath);
+	bool StoreExists = m_Storage->Exists();
+	if (StoreExists)
+	{
+		if (!m_Storage->IsValid())
+		{
+			ZEN_WARN("Invalid oplog found at '{}'. Wiping state for oplog.", m_BasePath);
+			StoreExists = false;
+		}
+	}
 	m_Storage->Open(/* IsCreate */ !StoreExists);
 	m_TempPath	= m_BasePath / "temp"sv;
 	m_MetaPath	= m_BasePath / "ops.meta"sv;