VFS implementation for local storage service (#396)

currently, only Windows (using Projected File System) is supported

2 files changed, 75 insertions, 8 deletions

diff --git a/src/zencore/filesystem.cpp b/src/zencore/filesystem.cpp
index b1ec14a37..e9f7ba72c 100644
--- a/src/zencore/filesystem.cpp
+++ b/src/zencore/filesystem.cpp
@@ -92,7 +92,7 @@ CreateDirectories(const wchar_t* Dir)
 // behind
 
 static bool
-WipeDirectory(const wchar_t* DirPath)
+WipeDirectory(const wchar_t* DirPath, bool KeepDotFiles)
 {
 	ExtendableWideStringBuilder<128> Pattern;
 	Pattern.Append(DirPath);
@@ -107,7 +107,7 @@ WipeDirectory(const wchar_t* DirPath)
 	{
 		do
 		{
-			bool IsRegular = true;
+			bool AttemptDelete = true;
 
 			if (FindData.cFileName[0] == L'.')
 			{
@@ -115,16 +115,21 @@ WipeDirectory(const wchar_t* DirPath)
 				{
 					if (FindData.cFileName[2] == L'\0')
 					{
-						IsRegular = false;
+						AttemptDelete = false;
 					}
 				}
 				else if (FindData.cFileName[1] == L'\0')
 				{
-					IsRegular = false;
+					AttemptDelete = false;
+				}
+
+				if (KeepDotFiles)
+				{
+					AttemptDelete = false;
 				}
 			}
 
-			if (IsRegular)
+			if (AttemptDelete)
 			{
 				ExtendableWideStringBuilder<128> Path;
 				Path.Append(DirPath);
@@ -188,7 +193,8 @@ WipeDirectory(const wchar_t* DirPath)
 bool
 DeleteDirectories(const wchar_t* DirPath)
 {
-	return WipeDirectory(DirPath) && RemoveDirectoryW(DirPath) == TRUE;
+	const bool KeepDotFiles = false;
+	return WipeDirectory(DirPath, KeepDotFiles) && RemoveDirectoryW(DirPath) == TRUE;
 }
 
 bool
@@ -196,7 +202,20 @@ CleanDirectory(const wchar_t* DirPath)
 {
 	if (std::filesystem::exists(DirPath))
 	{
-		return WipeDirectory(DirPath);
+		const bool KeepDotFiles = false;
+
+		return WipeDirectory(DirPath, KeepDotFiles);
+	}
+
+	return CreateDirectories(DirPath);
+}
+
+bool
+CleanDirectory(const wchar_t* DirPath, bool KeepDotFiles)
+{
+	if (std::filesystem::exists(DirPath))
+	{
+		return WipeDirectory(DirPath, KeepDotFiles);
 	}
 
 	return CreateDirectories(DirPath);
@@ -262,6 +281,19 @@ CleanDirectory(const std::filesystem::path& Dir)
 #endif
 }
 
+bool
+CleanDirectoryExceptDotFiles(const std::filesystem::path& Dir)
+{
+#if ZEN_PLATFORM_WINDOWS
+	const bool KeepDotFiles = true;
+	return CleanDirectory(Dir.c_str(), KeepDotFiles);
+#else
+	ZEN_UNUSED(Dir);
+
+	ZEN_NOT_IMPLEMENTED();
+#endif
+}
+
 //////////////////////////////////////////////////////////////////////////
 
 bool
@@ -950,7 +982,7 @@ FileSystemTraversal::TraverseFileSystem(const std::filesystem::path& RootDir, Tr
 
 	if (FAILED(hRes))
 	{
-		ThrowSystemException(hRes, "Failed to open handle to volume root");
+		ThrowSystemException(hRes, fmt::format("Failed to open handle to '{}'", RootDir));
 	}
 
 	while (Continue)
@@ -1063,6 +1095,33 @@ FileSystemTraversal::TraverseFileSystem(const std::filesystem::path& RootDir, Tr
 	closedir(Dir);
 #endif	// ZEN_PLATFORM_WINDOWS
 }
+
+std::filesystem::path
+CanonicalPath(std::filesystem::path InPath, std::error_code& Ec)
+{
+	ZEN_UNUSED(Ec);
+
+#if ZEN_PLATFORM_WINDOWS
+	windows::FileHandle Handle;
+	HRESULT				hRes = Handle.Create(InPath.c_str(),
+								 GENERIC_READ,
+								 FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+								 OPEN_EXISTING,
+								 FILE_FLAG_BACKUP_SEMANTICS);
+
+	if (FAILED(hRes))
+	{
+		Ec = MakeErrorCodeFromLastError();
+
+		return {};
+	}
+
+	return PathFromHandle(Handle, Ec);
+#else
+	return InPath;
+#endif
+}
+
 std::filesystem::path
 PathFromHandle(void* NativeHandle, std::error_code& Ec)
 {
diff --git a/src/zencore/include/zencore/filesystem.h b/src/zencore/include/zencore/filesystem.h
index a78edd16b..075188993 100644
--- a/src/zencore/include/zencore/filesystem.h
+++ b/src/zencore/include/zencore/filesystem.h
@@ -30,6 +30,10 @@ ZENCORE_API bool CreateDirectories(const std::filesystem::path& dir);
  */
 ZENCORE_API bool CleanDirectory(const std::filesystem::path& dir);
 
+/** Ensure directory exists and delete contents (if any) before returning
+ */
+ZENCORE_API bool CleanDirectoryExceptDotFiles(const std::filesystem::path& dir);
+
 /** Map native file handle to a path
  */
 ZENCORE_API std::filesystem::path PathFromHandle(void* NativeHandle);
@@ -38,6 +42,10 @@ ZENCORE_API std::filesystem::path PathFromHandle(void* NativeHandle);
  */
 ZENCORE_API std::filesystem::path PathFromHandle(void* NativeHandle, std::error_code& Ec);
 
+/** Get canonical path name from a generic path
+ */
+ZENCORE_API std::filesystem::path CanonicalPath(std::filesystem::path InPath, std::error_code& Ec);
+
 /** Query file size from native file handle
  */
 ZENCORE_API uint64_t FileSizeFromHandle(void* NativeHandle);