make sure initialization of a new filecas dont remove the cas manifest file or tiny/small cas store folders (#246)

* make sure initialization of a new filecas doesnt remove the cas manifest file or tiny/small cas store folders
* changelog

2 files changed, 38 insertions, 1 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 1409b276c..55f6410e0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,7 @@
 - Feature: CI build on GitHub now uploads junit test reports as artifact to the check for PR validation and mainline validation
 - Feature: Payloads from zenserver can now be sent using duplicated file handles if caller requests provides client ProcessId (Windows only).
 - Bugfix: Make sure async responses are sent async correctly in httpsys
+- Bugfix: Don't delete manifest file in cas root when initializing a new filecas folder
 - Improvement: FileCas now keeps an up to date index of all the entries improving performance when getting cache misses on large payloads
 - Improvement: Structured cache now keeps RawHash and RawSize in memory avoiding materialization of cache values before sending response
 - Changed: Exit with failure code on port conflict rather than reporting crash to Sentry
diff --git a/zenstore/filecas.cpp b/zenstore/filecas.cpp
index 5b4a2aabc..b4729d558 100644
--- a/zenstore/filecas.cpp
+++ b/zenstore/filecas.cpp
@@ -138,7 +138,43 @@ FileCasStrategy::Initialize(const std::filesystem::path& RootDirectory, bool IsN
 	{
 		std::filesystem::remove(LogPath);
 		std::filesystem::remove(IndexPath);
-		std::filesystem::remove_all(RootDirectory);
+
+		if (std::filesystem::is_directory(m_RootDirectory))
+		{
+			// We need to explicitly only delete sharded root folders as the cas manifest, tinyobject and smallobject cas folders may reside
+			// in this folder as well
+			struct Visitor : public FileSystemTraversal::TreeVisitor
+			{
+				virtual void VisitFile(const std::filesystem::path&, const path_view&, uint64_t) override
+				{
+					// We don't care about files
+				}
+				static bool IsHexChar(std::filesystem::path::value_type C)
+				{
+					return std::find(&HexChars[0], &HexChars[16], C) != &HexChars[16];
+				}
+				virtual bool VisitDirectory([[maybe_unused]] const std::filesystem::path& Parent,
+											[[maybe_unused]] const path_view&			  DirectoryName) override
+				{
+					if (DirectoryName.length() == 3)
+					{
+						if (IsHexChar(DirectoryName[0]) && IsHexChar(DirectoryName[1]) && IsHexChar(DirectoryName[2]))
+						{
+							ShardedRoots.push_back(Parent / DirectoryName);
+						}
+					}
+					return false;
+				}
+				std::vector<std::filesystem::path> ShardedRoots;
+			} CasVisitor;
+
+			FileSystemTraversal Traversal;
+			Traversal.TraverseFileSystem(m_RootDirectory, CasVisitor);
+			for (const std::filesystem::path& SharededRoot : CasVisitor.ShardedRoots)
+			{
+				std::filesystem::remove_all(SharededRoot);
+			}
+		}
 	}
 
 	m_LogFlushPosition	   = ReadIndexFile();