Cleaned up exception handling

We now use std::system_error where possible to report Win32 system errors. We still have WindowsException for general HRESULT based errors but we should phase it out where possible

6 files changed, 34 insertions, 28 deletions

diff --git a/zencore/except.cpp b/zencore/except.cpp
index b02122f58..882f69f9a 100644
--- a/zencore/except.cpp
+++ b/zencore/except.cpp
@@ -1,17 +1,27 @@
 // Copyright Epic Games, Inc. All Rights Reserved.
 
 #include <zencore/except.h>
+#include <system_error>
 
 namespace zen {
 
 void
-ThrowSystemException([[maybe_unused]] HRESULT hRes, [[maybe_unused]] const char* Message)
+ThrowSystemException([[maybe_unused]] HRESULT hRes, [[maybe_unused]] std::string_view Message)
 {
-	// TODO
-
-	int ErrValue = hRes;
+	if (HRESULT_FACILITY(hRes) == FACILITY_WIN32)
+	{
+		throw std::system_error(std::error_code(hRes & 0xffff, std::system_category()), std::string(Message));
+	}
+	else
+	{
+		throw WindowsException(hRes, Message);
+	}
+}
 
-	throw std::system_error(ErrValue, std::system_category(), Message);
+void
+ThrowLastError(std::string_view Message)
+{
+	throw std::system_error(std::error_code(::GetLastError(), std::system_category()), std::string(Message));
 }
 
 }  // namespace zen
diff --git a/zencore/filesystem.cpp b/zencore/filesystem.cpp
index 578b28277..cb806b276 100644
--- a/zencore/filesystem.cpp
+++ b/zencore/filesystem.cpp
@@ -409,7 +409,7 @@ WriteFile(std::filesystem::path Path, const IoBuffer* const* Data, size_t Buffer
 	HRESULT	 hRes = Outfile.Create(Path.c_str(), GENERIC_WRITE, FILE_SHARE_READ, CREATE_ALWAYS);
 	if (FAILED(hRes))
 	{
-		zen::ThrowIfFailed(hRes, "File open failed for '{}'"_format(Path).c_str());
+		zen::ThrowSystemException(hRes, "File open failed for '{}'"_format(Path).c_str());
 	}
 
 	// TODO: this could be block-enlightened
@@ -427,7 +427,7 @@ WriteFile(std::filesystem::path Path, const IoBuffer* const* Data, size_t Buffer
 
 			if (FAILED(hRes))
 			{
-				zen::ThrowIfFailed(hRes, "File write failed for '{}'"_format(Path).c_str());
+				zen::ThrowSystemException(hRes, "File write failed for '{}'"_format(Path).c_str());
 			}
 
 			WriteSize -= ChunkSize;
@@ -517,7 +517,7 @@ FileSystemTraversal::TraverseFileSystem(const std::filesystem::path& RootDir, Tr
 										 OPEN_EXISTING,
 										 FILE_FLAG_BACKUP_SEMANTICS);
 
-	zen::ThrowIfFailed(hRes, "Failed to open handle to volume root");
+	zen::ThrowSystemException(hRes, "Failed to open handle to volume root");
 
 	while (Continue)
 	{
diff --git a/zencore/include/zencore/except.h b/zencore/include/zencore/except.h
index 8f5f50e86..782dbeed0 100644
--- a/zencore/include/zencore/except.h
+++ b/zencore/include/zencore/except.h
@@ -11,18 +11,12 @@ namespace zen {
 class WindowsException : public std::exception
 {
 public:
-	WindowsException(const char* Message)
+	WindowsException(std::string_view Message)
 	{
 		m_hResult = HRESULT_FROM_WIN32(GetLastError());
 		m_Message = Message;
 	}
 
-	WindowsException(HRESULT hRes, const char* Message)
-	{
-		m_hResult = hRes;
-		m_Message = Message;
-	}
-
 	WindowsException(HRESULT hRes, std::string_view Message)
 	{
 		m_hResult = hRes;
@@ -49,18 +43,14 @@ private:
 	HRESULT		m_hResult;
 };
 
-ZENCORE_API void ThrowSystemException(HRESULT hRes, const char* Message);
+ZENCORE_API void ThrowSystemException(HRESULT hRes, std::string_view Message);
+
 inline void
 ThrowSystemException(const char* Message)
 {
 	throw WindowsException(Message);
 }
 
-inline void
-ThrowIfFailed(HRESULT hRes, const char* Message)
-{
-	if (FAILED(hRes))
-		ThrowSystemException(hRes, Message);
-}
+ZENCORE_API void ThrowLastError(std::string_view Message);
 
 }  // namespace zen
diff --git a/zencore/thread.cpp b/zencore/thread.cpp
index 80cf6f100..4451fd302 100644
--- a/zencore/thread.cpp
+++ b/zencore/thread.cpp
@@ -58,13 +58,15 @@ Event::Reset()
 bool
 Event::Wait(int TimeoutMs)
 {
+	using namespace std::literals;
+
 	const DWORD Timeout = (TimeoutMs < 0) ? INFINITE : TimeoutMs;
 
 	DWORD Result = WaitForSingleObject(m_EventHandle, Timeout);
 
 	if (Result == WAIT_FAILED)
 	{
-		throw WindowsException("Event wait failed");
+		zen::ThrowLastError("Event wait failed"sv);
 	}
 
 	return (Result == WAIT_OBJECT_0);
diff --git a/zenserver/experimental/usnjournal.cpp b/zenserver/experimental/usnjournal.cpp
index f44e50945..a266c2338 100644
--- a/zenserver/experimental/usnjournal.cpp
+++ b/zenserver/experimental/usnjournal.cpp
@@ -164,7 +164,10 @@ UsnJournalReader::Initialize(std::filesystem::path VolumePath)
 	HRESULT	 hRes =
 		VolumeRootDir.Create(VolumePathName, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS);
 
-	ThrowIfFailed(hRes, "Failed to open handle to volume root");
+	if (FAILED(hRes))
+	{
+		ThrowSystemException(hRes, "Failed to open handle to volume root");
+	}
 
 	FILE_ID_INFO FileInformation{};
 	BOOL		 Success = GetFileInformationByHandleEx(VolumeRootDir, FileIdInfo, &FileInformation, sizeof FileInformation);
diff --git a/zenstore/caslog.cpp b/zenstore/caslog.cpp
index 4b9aacb42..0ef3ed1bd 100644
--- a/zenstore/caslog.cpp
+++ b/zenstore/caslog.cpp
@@ -125,7 +125,10 @@ CasLogFile::Replay(std::function<void(const void*)>&& Handler)
 	m_File.Seek(LogBaseOffset, FILE_BEGIN);
 	HRESULT hRes = m_File.Read(ReadBuffer.data(), gsl::narrow<DWORD>(LogDataSize));
 
-	zen::ThrowIfFailed(hRes, "Failed to read log file");
+	if (FAILED(hRes))
+	{
+		zen::ThrowSystemException(hRes, "Failed to read log file");
+	}
 
 	for (int i = 0; i < LogEntryCount; ++i)
 	{
@@ -140,9 +143,7 @@ CasLogFile::Append(const void* DataPointer, uint64_t DataSize)
 
 	if (FAILED(hRes))
 	{
-		throw std::system_error(GetLastError(),
-								std::system_category(),
-								"Failed to write to log file '{}'"_format(zen::PathFromHandle(m_File)));
+		zen::ThrowSystemException(hRes, "Failed to write to log file '{}'"_format(zen::PathFromHandle(m_File)));
 	}
 }