Deliver/include/Log4CPP8.0/Common.Include/FileStream.hpp

#pragma once


#include "String.StringView.hpp"
using namespace ECOM::Utility::String::Literals;

#include "Utility.Expected.tlh"


//---------------------------------------------------------------------
//  关于共享模式
//  FileBuffer类中定义共享模式
//    Open函数中没有用缺省参数
//  IFileStreamBuffer的
//    OpenForRead函数中使用缺省参数 shareDenyNone,即允许各种共享
//  OFileStreamBuffer的
//    OpenForWrite函数中使用缺省参数 shareDenyWrite, 即不允许其它写操作
//    OpenForAppend函数中使用缺省参数 shareDenyWrite, 即不允许其它写操作
//  DICOMFileBuffer的
//    OpenForRead函数中使用缺省参数 shareDenyWrite, 即不允许其它写操作
//    OpenForWrite函数中使用缺省参数 shareExclusive, 即不允许其它任何操作, 其它读操作当然也不允许
//---------------------------------------------------------------------


//-----------------------------------------------------------------------------
//		FileStreamBase
//-----------------------------------------------------------------------------
class FileStreamBase
{
protected:
	using eiResult = ECOM::Utility::Expected <int>;
	static constexpr auto eiSuccess = ECOM::Utility::left <int> (1);

public:
	enum enShareMode
	{
		shareCompat     =  (int) 0x00000,
		shareExclusive  =  (int) 0x00010,
		shareDenyWrite  =  (int) 0x00020,
		shareDenyRead   =  (int) 0x00030,
		shareDenyNone   =  (int) 0x00040,
	};

	FileStreamBase () { m_hFile = INVALID_HANDLE_VALUE; m_bEOF = true; }
	virtual ~FileStreamBase () { Close (); }

	FileStreamBase (const FileStreamBase & FS) = delete;
	FileStreamBase (FileStreamBase && from)
	{
		this->m_bEOF  = from.m_bEOF;
		this->m_hFile = from.m_hFile;

		from.m_bEOF  = true;
		from.m_hFile = INVALID_HANDLE_VALUE;
	}

	FileStreamBase & operator = (const FileStreamBase & OB) = delete;
	FileStreamBase & operator = (FileStreamBase && OB) = delete;

public:
	virtual eiResult Open (const wchar_t * filename, enShareMode mode) = 0;
	virtual	void Close (void) { CloseFile (); }

	void CloseFile (void);

	void	SeekToBegin (void);
	UINT32	SeekToEnd   (void);
	virtual LONG Seek   (LONG lOff, UINT nFrom);

	virtual	DWORD GetLength (void) const;
	virtual	DWORD GetLengthMB (void) const;
	virtual DWORD GetPosition (void) const;

	enum SeekPosition { begin = 0x0, current = 0x1, end = 0x2 };

	virtual	bool IsEOF (void) const;

protected:
	enum enOpenMode
	{
		enRead   = 'R',
		enWrite  = 'W',
		enAppend = 'A'
	};

	eiResult DoOpenRW (PCWSTR FileName, enShareMode Mode, enOpenMode RWA);

	void OnError (DWORD errCode, PCWSTR FileName);

protected:
	bool	m_bEOF;
	HANDLE	m_hFile;
};


//-----------------------------------------------------------------------------///
//		IFileStream Class, no-cache available
//-----------------------------------------------------------------------------///
class IFileStream : public FileStreamBase
{
public:
	IFileStream () = default;
	IFileStream (const wchar_t * filename) { OpenForRead (filename); }
	~IFileStream () { Close (); }

	IFileStream (const IFileStream& FS) = delete;
	IFileStream (IFileStream && from) : FileStreamBase (std::move (from)) {}

	IFileStream & operator = (const IFileStream & OB) = delete;
	IFileStream & operator = (IFileStream && OB) = delete;

public:
	virtual eiResult Open (const wchar_t * filename, enShareMode mode) override  { return OpenForRead (filename, mode); }

	eiResult Open (PCWSTR filename) { return OpenForRead (filename); }

	DWORD ReadFile (void * Data, int cbNumBytes);

	eiResult OpenForRead (const wchar_t * filename, enShareMode mode = shareDenyWrite);

//  return the new positon after seek
	inline UINT Kill  (UINT Bytes)
	{
		return Seek (Bytes, current);
	}

	inline bool	IsExist (const wchar_t * FileName)
	{
		bool rc = OpenForRead (FileName);
		Close ();
		return rc;
	}
};


//-----------------------------------------------------------------------------///
//		OFileStream Class, no-cache available
//-----------------------------------------------------------------------------///
class OFileStream : public FileStreamBase
{
public:
	OFileStream () = default;
	OFileStream (const wchar_t * filename)  { OpenForWrite (filename); }
	~OFileStream ()  { Close (); }

	OFileStream (const OFileStream & FS) = delete;
	OFileStream (OFileStream && from) : FileStreamBase (std::move (from)) {}

	OFileStream & operator = (const OFileStream & OB) = delete;
	OFileStream & operator = (OFileStream && OB) = delete;

public:
	virtual eiResult Open (const wchar_t * filename, enShareMode mode) override  { return OpenForWrite (filename, mode); }

	eiResult Open (PCWSTR filename) { return OpenForWrite (filename); }

	DWORD WriteFile (const void * Data, int cbNumBytes);

	eiResult OpenForWrite  (const wchar_t * filename, enShareMode mode = shareExclusive);
	eiResult OpenForAppend (const wchar_t * filename, enShareMode mode = shareExclusive);
};




//-----------------------------------------------------------------------------///
//		FileStreamBase
//-----------------------------------------------------------------------------///

template <typename T>
std::enable_if_t <(sizeof (T) == sizeof (unsigned long long)), T>
__LockedExch (volatile T * h, T v)
{
	auto rc = InterlockedExchange (reinterpret_cast <volatile unsigned long long *> (h), reinterpret_cast <unsigned long long> (v));
	return reinterpret_cast <T> (rc);
}

template <typename T>
std::enable_if_t <(sizeof (T) == sizeof (unsigned long)), T>
__LockedExch (volatile T * h, T v)
{
	auto rc = InterlockedExchange (reinterpret_cast <volatile unsigned long *> (h), reinterpret_cast <unsigned long> (v));
	return reinterpret_cast <T> (rc);
}


inline void FileStreamBase::CloseFile (void)
{
	auto fh = __LockedExch (& m_hFile, INVALID_HANDLE_VALUE);
	if (fh == INVALID_HANDLE_VALUE)  
		return;

	CloseHandle (fh);
//	m_hFile = INVALID_HANDLE_VALUE;
	m_bEOF = true;
}


inline UINT32 FileStreamBase::SeekToEnd (void)
{
	return Seek (0, end);
}


inline void FileStreamBase::SeekToBegin (void)
{
	Seek (0, begin);
}


// return the new position after seek
inline LONG FileStreamBase::Seek (LONG lOff, UINT nFrom)
{
	if (m_hFile == INVALID_HANDLE_VALUE)
		return -1;

	LONG rc = -1;
	switch (nFrom)
	{
	case begin  : rc = ::SetFilePointer (m_hFile, lOff, NULL, FILE_BEGIN);  break;
	case current: rc = ::SetFilePointer (m_hFile, lOff, NULL, FILE_CURRENT);  break;
	case end    : rc = ::SetFilePointer (m_hFile, lOff, NULL, FILE_END);  break;
	}

	if (rc == -1)
		return 0;

	return rc;
}


//	多少字节
inline DWORD FileStreamBase::GetLength (void) const
{
	DWORD hi = 0;
	DWORD lo = GetFileSize (m_hFile, &hi);
	if (lo == -1)
		lo = 0;
	return lo;
}

//	多少 MB
inline DWORD FileStreamBase::GetLengthMB (void) const
{
	DWORD hi = 0;
	DWORD lo = GetFileSize (m_hFile, &hi);
	if (lo == -1)
		lo = 0;

	hi <<= 12;
	lo >>= 20;

	return hi + lo;
}


inline DWORD FileStreamBase::GetPosition (void) const
{
	return ::SetFilePointer (m_hFile, 0, NULL, FILE_CURRENT);
}


inline bool FileStreamBase::IsEOF (void) const
{
	return m_bEOF;
}


inline auto FileStreamBase::DoOpenRW (PCWSTR FileName, enShareMode Mode, enOpenMode RWA) -> eiResult
{
	Close ();

	// map share mode
	DWORD dwShareMode = 0;
	switch (Mode)    // map compatibility mode to exclusive
	{
	default:
		ASSERT(false);  // invalid share mode?
	case shareCompat:
	case shareExclusive:
		dwShareMode = 0;
		break;
	case shareDenyWrite:
		dwShareMode = FILE_SHARE_READ;
		break;
	case shareDenyRead:
		dwShareMode = FILE_SHARE_WRITE;
		break;
	case shareDenyNone:
		dwShareMode = FILE_SHARE_WRITE | FILE_SHARE_READ;
		break;
	}

	DWORD dwAccess = GENERIC_READ;
	if (RWA == enOpenMode::enRead)    dwAccess = GENERIC_READ;
	else
	if (RWA == enOpenMode::enWrite)   dwAccess = GENERIC_WRITE;
	else
	if (RWA == enOpenMode::enAppend)  dwAccess = GENERIC_WRITE;
	else
		assert (false);

	DWORD dwDisposition = OPEN_EXISTING;
	if (RWA == enOpenMode::enRead)    dwDisposition = OPEN_EXISTING;
	else
	if (RWA == enOpenMode::enWrite)   dwDisposition = CREATE_ALWAYS;
	else
	if (RWA == enOpenMode::enAppend)  dwDisposition = OPEN_EXISTING;
	else
		assert (false);

	m_hFile = CreateFileW (
		FileName,
		dwAccess,
		dwShareMode,
		NULL,
		dwDisposition,
		FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN,
		NULL);
	if (m_hFile == INVALID_HANDLE_VALUE)
	{
		auto ec = GetLastError ();
		OnError (ec, FileName);
		SetLastError (ec);
//		return false;
		return ECOM::Utility::Error::OS::Windows::Make (ec);
	}

	m_bEOF = false;

	return eiSuccess;
}


//-----------------------------------------------------------------------------///
//		IFileBuffer
//-----------------------------------------------------------------------------///
inline auto IFileStream::OpenForRead (const wchar_t * filename, enShareMode Mode) -> eiResult
{
	return DoOpenRW (filename, Mode, enOpenMode::enRead);
}


inline DWORD IFileStream::ReadFile (void * Data, int Length)
{
	DWORD cbRead = 0;
	if (! ::ReadFile (m_hFile, Data, Length, & cbRead, NULL))
	{
#ifdef _DEBUG
		DWORD error = GetLastError ();
#endif
		FileStreamBase::m_bEOF = true;
		return 0;
	}

	if (! cbRead)
	{
		FileStreamBase::m_bEOF = true;
		return 0;
	}

	return cbRead;
}


//-----------------------------------------------------------------------------///
//		OFileStream
//-----------------------------------------------------------------------------///
inline auto OFileStream::OpenForWrite (const wchar_t * filename, enShareMode Mode) -> eiResult
{
	return DoOpenRW (filename, Mode, enOpenMode::enWrite);
}

inline auto OFileStream::OpenForAppend (const wchar_t * filename, enShareMode Mode) -> eiResult
{
	auto rc = DoOpenRW (filename, Mode, enOpenMode::enAppend);
	if (! rc)
		rc = DoOpenRW (filename, Mode, enOpenMode::enWrite);
	if (! rc)  return rc;

	SeekToEnd ();
	return eiSuccess;
}


inline DWORD OFileStream::WriteFile (const void * Data, int Length)
{
	if (Length <= 0)  return 0;

	DWORD cbWrite = 0;
	if (! ::WriteFile (m_hFile, Data, Length, & cbWrite, NULL))
	{
		FileStreamBase::m_bEOF = true;
		return 0;
	}

	if (! cbWrite)
	{
		FileStreamBase::m_bEOF = true;
		return 0;
	}

	return cbWrite;
}




inline const IFileStream & operator >> (const IFileStream & IFS, std::string & s)
{
	auto len = IFS.GetLength ();
	if (len <= 0)  return IFS;
	s.resize (len);
	auto pc = s.data ();
	const_cast <IFileStream &> (IFS).ReadFile (pc, len);
	return IFS;
}

inline const OFileStream & operator << (const OFileStream & OFS, const std::string_view & s)
{
	const_cast <OFileStream &> (OFS).WriteFile (s.data (), static_cast <int> (s.size ()));
	return OFS;
}

inline const OFileStream & operator << (const OFileStream & OFS, const std::string & s)
{
	const_cast <OFileStream &> (OFS).WriteFile (s.data (), static_cast <int> (s.size ()));
	return OFS;
}


#ifdef DSTRING_API

// 用 const 是为了解决如下语句的编译错误: IFileStream (FN) >> strXMLImageTag;

//inline IFileStream & operator >> (IFileStream & IFS, eSTR::DString & s)
inline const IFileStream & operator >> (const IFileStream & IFS, eSTR::DString & s)
{
	auto len = IFS.GetLength ();
	if (len <= 0)  return IFS;
	auto pc = s.GetBufferSetLength (len);
	const_cast <IFileStream &> (IFS).ReadFile (pc, len);
	return IFS;
}

inline const OFileStream & operator << (const OFileStream & OFS, const eSTR::DStringView & s)
{
	const_cast <OFileStream &> (OFS).WriteFile (s, s.GetLength ());
	return OFS;
}

inline const OFileStream & operator << (const OFileStream & OFS, const eSTR::DString & s)
{
	const_cast <OFileStream &> (OFS).WriteFile (s, s.GetByteLength ());
	return OFS;
}

#endif


#ifdef WSTRING_API

inline const IFileStream & operator >> (const IFileStream & IFS, eSTR::WString & s)
{
	auto len = IFS.GetLength ();
	if (len <= 0)  return IFS;
	auto pc = s.GetBufferSetLength (len/2);
	const_cast <IFileStream &> (IFS).ReadFile (pc, len);
	return IFS;
}

inline const OFileStream & operator << (const OFileStream & OFS, const eSTR::WStringView & s)
{
	const_cast <OFileStream &> (OFS).WriteFile (s, s.GetLength () << 1);
	return OFS;
}

inline const OFileStream & operator << (const OFileStream & OFS, const eSTR::WString & s)
{
	const_cast <OFileStream &> (OFS).WriteFile (s, s.GetByteLength ());
	return OFS;
}

#endif



#ifdef __TmplBlockBuffer__

inline const IFileStream & operator >> (const IFileStream & IFS, BlockBuffer & s)
{
	auto len = IFS.GetLength ();
	if (len <= 0)  return IFS;
	auto pc = s.GetBufferSetCount (len);
	const_cast <IFileStream &> (IFS).ReadFile (pc, len);
	return IFS;
}

inline const OFileStream & operator << (const OFileStream & OFS, const BlockBuffer & s)
{
	const_cast <OFileStream &> (OFS).WriteFile (s, s.GetNbOfBytes ());
	return OFS;
}


inline const IFileStream & operator >> (const IFileStream & IFS, OBlockBuffer & s)
{
	auto len = IFS.GetLength ();
	if (len <= 0)  return IFS;
	auto pc = s.GetBufferSetCount (len);
	const_cast <IFileStream &> (IFS).ReadFile (pc, len);
	return IFS;
}

inline const OFileStream & operator << (const OFileStream & OFS, const OBlockBuffer & s)
{
	const_cast <OFileStream &> (OFS).WriteFile (s, s.GetNbOfBytes ());
	return OFS;
}

#endif



#ifdef __M_LOG_LOG4CPP__

inline void FileStreamBase::OnError (DWORD errCode, PCWSTR FileName)
{
	mLog::Error ("Failed at FileStreamBase.DoOpenRW, {$} FileName : <{$}>"_sv,
		mLog::ErrorCodeToString (errCode), FileName);
}

#else

inline void FileStreamBase::OnError (DWORD errCode, PCWSTR FileName)
{
}

#endif