Fix correctness and concurrency bugs found during code review

zenstore fixes:
- cas.cpp: GetFileCasResults Results param passed by value instead of reference (large chunk results were silently lost)
- structuredcachestore.cpp: MissCount unconditionally incremented (counted hits as misses)
- cacherpc.cpp: Wrong boolean in Incomplete response array (all entries marked incomplete)
- cachedisklayer.cpp: sizeof(sizeof(...)) in two validation checks computed sizeof(size_t) instead of struct size
- buildstore.cpp: Wrong hash tracked in GC key list (BlobHash pushed twice instead of MetadataHash)
- buildstore.cpp: Removed duplicate m_LastAccessTimeUpdateCount increment in PutBlob

zenserver fixes:
- httpbuildstore.cpp: Reversed subtraction in HTTP range calculation (unsigned underflow)
- hubservice.cpp: Deadlock in Provision() calling Wake() while holding m_Lock (extracted WakeLocked helper)
- zipfs.cpp: Data race in GetFile() lazy initialization (added RwLock with shared/exclusive paths)

Co-Authored-By: Claude Opus 4.6 <[email protected]>

2 files changed, 18 insertions, 4 deletions

diff --git a/src/zenserver/frontend/zipfs.cpp b/src/zenserver/frontend/zipfs.cpp
index f9c2bc8ff..42df0520f 100644
--- a/src/zenserver/frontend/zipfs.cpp
+++ b/src/zenserver/frontend/zipfs.cpp
@@ -149,13 +149,25 @@ ZipFs::ZipFs(IoBuffer&& Buffer)
 IoBuffer
 ZipFs::GetFile(const std::string_view& FileName) const
 {
-	FileMap::iterator Iter = m_Files.find(FileName);
-	if (Iter == m_Files.end())
 	{
-		return {};
+		RwLock::SharedLockScope _(m_FilesLock);
+
+		FileMap::const_iterator Iter = m_Files.find(FileName);
+		if (Iter == m_Files.end())
+		{
+			return {};
+		}
+
+		const FileItem& Item = Iter->second;
+		if (Item.GetSize() > 0)
+		{
+			return IoBuffer(IoBuffer::Wrap, Item.GetData(), Item.GetSize());
+		}
 	}
 
-	FileItem& Item = Iter->second;
+	RwLock::ExclusiveLockScope _(m_FilesLock);
+
+	FileItem& Item = m_Files.find(FileName)->second;
 	if (Item.GetSize() > 0)
 	{
 		return IoBuffer(IoBuffer::Wrap, Item.GetData(), Item.GetSize());
diff --git a/src/zenserver/frontend/zipfs.h b/src/zenserver/frontend/zipfs.h
index 1fa7da451..19f96567c 100644
--- a/src/zenserver/frontend/zipfs.h
+++ b/src/zenserver/frontend/zipfs.h
@@ -3,6 +3,7 @@
 #pragma once
 
 #include <zencore/iobuffer.h>
+#include <zencore/thread.h>
 
 #include <unordered_map>
 
@@ -20,6 +21,7 @@ public:
 private:
 	using FileItem = MemoryView;
 	using FileMap  = std::unordered_map<std::string_view, FileItem>;
+	mutable RwLock m_FilesLock;
 	FileMap mutable m_Files;
 	IoBuffer m_Buffer;
 };