New rotating file logger that keeps on running regardless of errors (#495)

* New rotating file logger that keeps on running regardless of errors

2 files changed, 35 insertions, 1 deletions

diff --git a/src/zenutil/basicfile.cpp b/src/zenutil/basicfile.cpp
index 259d622c4..1dce71e60 100644
--- a/src/zenutil/basicfile.cpp
+++ b/src/zenutil/basicfile.cpp
@@ -365,7 +365,39 @@ BasicFile::FileSize()
 	int Fd = int(uintptr_t(m_FileHandle));
 	static_assert(sizeof(decltype(stat::st_size)) == sizeof(uint64_t), "fstat() doesn't support large files");
 	struct stat Stat;
-	fstat(Fd, &Stat);
+	if (fstat(Fd, &Stat) == -1)
+	{
+		ThrowSystemError(GetLastError(), fmt::format("Failed to get file size from file '{}'", PathFromHandle(m_FileHandle)));
+	}
+	return uint64_t(Stat.st_size);
+#endif
+}
+
+uint64_t
+BasicFile::FileSize(std::error_code& Ec)
+{
+#if ZEN_PLATFORM_WINDOWS
+	ULARGE_INTEGER liFileSize;
+	liFileSize.LowPart = ::GetFileSize(m_FileHandle, &liFileSize.HighPart);
+	if (liFileSize.LowPart == INVALID_FILE_SIZE)
+	{
+		int Error = zen::GetLastError();
+		if (Error)
+		{
+			Ec = MakeErrorCode(Error);
+			return 0;
+		}
+	}
+	return uint64_t(liFileSize.QuadPart);
+#else
+	int Fd = int(uintptr_t(m_FileHandle));
+	static_assert(sizeof(decltype(stat::st_size)) == sizeof(uint64_t), "fstat() doesn't support large files");
+	struct stat Stat;
+	if (fstat(Fd, &Stat) == -1)
+	{
+		Ec = MakeErrorCodeFromLastError();
+		return 0;
+	}
 	return uint64_t(Stat.st_size);
 #endif
 }
diff --git a/src/zenutil/include/zenutil/basicfile.h b/src/zenutil/include/zenutil/basicfile.h
index eb97c885c..7797258e8 100644
--- a/src/zenutil/include/zenutil/basicfile.h
+++ b/src/zenutil/include/zenutil/basicfile.h
@@ -62,12 +62,14 @@ public:
 	void	 Write(const void* Data, uint64_t Size, uint64_t FileOffset, std::error_code& Ec);
 	void	 Flush();
 	[[nodiscard]] uint64_t FileSize();
+	[[nodiscard]] uint64_t FileSize(std::error_code& Ec);
 	void				   SetFileSize(uint64_t FileSize);
 	IoBuffer			   ReadAll();
 	void				   WriteAll(IoBuffer Data, std::error_code& Ec);
 	void*				   Detach();
 
 	inline void* Handle() { return m_FileHandle; }
+	bool		 IsOpen() const { return m_FileHandle != nullptr; }
 
 protected:
 	void* m_FileHandle = nullptr;  // This is either null or valid