tweaks for enabling unity builds

mostly changes to make sure anonymous namespaces don't clash and a change to avoid windows headers from leaking into other compilation units

unity builds are not yet enabled by default, but can be enabled by uncommenting this line in the root `xmake.lua`

```
--add_rules("c++.unity_build")
```

1 files changed, 16 insertions, 6 deletions

diff --git a/zenstore/filecas.cpp b/zenstore/filecas.cpp
index b4729d558..986cc9ae6 100644
--- a/zenstore/filecas.cpp
+++ b/zenstore/filecas.cpp
@@ -39,7 +39,7 @@ ZEN_THIRD_PARTY_INCLUDES_END
 
 namespace zen {
 
-namespace {
+namespace filecas::impl {
 	const char* IndexExtension = ".uidx";
 	const char* LogExtension   = ".ulog";
 
@@ -77,7 +77,7 @@ namespace {
 
 #pragma pack(pop)
 
-}  // namespace
+}  // namespace filecas::impl
 
 FileCasStrategy::ShardingHelper::ShardingHelper(const std::filesystem::path& RootPath, const IoHash& ChunkHash)
 {
@@ -125,6 +125,8 @@ FileCasStrategy::~FileCasStrategy()
 void
 FileCasStrategy::Initialize(const std::filesystem::path& RootDirectory, bool IsNewStore)
 {
+	using namespace filecas::impl;
+
 	m_IsInitialized = true;
 
 	m_RootDirectory = RootDirectory;
@@ -1013,6 +1015,8 @@ FileCasStrategy::ValidateEntry(const FileCasIndexEntry& Entry, std::string& OutR
 void
 FileCasStrategy::MakeIndexSnapshot()
 {
+	using namespace filecas::impl;
+
 	uint64_t LogCount = m_CasLog.GetLogCount();
 	if (m_LogFlushPosition == LogCount)
 	{
@@ -1062,12 +1066,12 @@ FileCasStrategy::MakeIndexSnapshot()
 
 		BasicFile ObjectIndexFile;
 		ObjectIndexFile.Open(IndexPath, BasicFile::Mode::kTruncate);
-		FileCasIndexHeader Header = {.EntryCount = Entries.size(), .LogPosition = LogCount};
+		filecas::impl::FileCasIndexHeader Header = {.EntryCount = Entries.size(), .LogPosition = LogCount};
 
-		Header.Checksum = FileCasIndexHeader::ComputeChecksum(Header);
+		Header.Checksum = filecas::impl::FileCasIndexHeader::ComputeChecksum(Header);
 
-		ObjectIndexFile.Write(&Header, sizeof(FileCasIndexHeader), 0);
-		ObjectIndexFile.Write(Entries.data(), Entries.size() * sizeof(FileCasIndexEntry), sizeof(FileCasIndexHeader));
+		ObjectIndexFile.Write(&Header, sizeof(filecas::impl::FileCasIndexHeader), 0);
+		ObjectIndexFile.Write(Entries.data(), Entries.size() * sizeof(FileCasIndexEntry), sizeof(filecas::impl::FileCasIndexHeader));
 		ObjectIndexFile.Flush();
 		ObjectIndexFile.Close();
 		EntryCount		   = Entries.size();
@@ -1093,6 +1097,8 @@ FileCasStrategy::MakeIndexSnapshot()
 uint64_t
 FileCasStrategy::ReadIndexFile()
 {
+	using namespace filecas::impl;
+
 	std::vector<FileCasIndexEntry> Entries;
 	std::filesystem::path		   IndexPath = GetIndexPath(m_RootDirectory);
 	if (std::filesystem::is_regular_file(IndexPath))
@@ -1179,6 +1185,8 @@ FileCasStrategy::ReadIndexFile()
 uint64_t
 FileCasStrategy::ReadLog(uint64_t SkipEntryCount)
 {
+	using namespace filecas::impl;
+
 	std::filesystem::path LogPath = GetLogPath(m_RootDirectory);
 	if (std::filesystem::is_regular_file(LogPath))
 	{
@@ -1230,6 +1238,8 @@ FileCasStrategy::ReadLog(uint64_t SkipEntryCount)
 std::vector<FileCasStrategy::FileCasIndexEntry>
 FileCasStrategy::ScanFolderForCasFiles(const std::filesystem::path& RootDir)
 {
+	using namespace filecas::impl;
+
 	std::vector<FileCasIndexEntry> Entries;
 	struct Visitor : public FileSystemTraversal::TreeVisitor
 	{