The purpose of this file is to provide implementation of file IO routines on Windows that can be thought as drop-in replacement for corresponding C runtime functionality. More...

#include <algorithm>
#include <iostream>
#include <vector>
#include <errno.h>
#include <fcntl.h>
#include <io.h>
#include <share.h>
#include <sys/stat.h>
#include "mutex_lock.h"
#include "my_dbug.h"
#include "my_io.h"
#include "my_sys.h"
#include "my_thread_local.h"
#include "mysql/psi/mysql_mutex.h"
#include "mysys_priv.h"
#include "scope_guard.h"
#include "sql/malloc_allocator.h"

Classes
class	anonymous_namespace{my_winfile.cc}::WindowsErrorGuard
	RAII guard which ensures that: More...

struct	anonymous_namespace{my_winfile.cc}::HandleInfo

Namespaces
namespace	anonymous_namespace{my_winfile.cc}

Typedefs
using	anonymous_namespace{my_winfile.cc}::HandleInfoAllocator = Malloc_allocator< HandleInfo >

using	anonymous_namespace{my_winfile.cc}::HandleInfoVector = std::vector< HandleInfo, HandleInfoAllocator >

Functions
size_t	anonymous_namespace{my_winfile.cc}::ToIndex (File fd)

int	anonymous_namespace{my_winfile.cc}::ToDescr (size_t hi)

bool	anonymous_namespace{my_winfile.cc}::IsValidIndex (size_t hi)

HandleInfo	anonymous_namespace{my_winfile.cc}::GetHandleInfo (File fd)

File	anonymous_namespace{my_winfile.cc}::RegisterHandle (HANDLE handle, int oflag)

HandleInfo	anonymous_namespace{my_winfile.cc}::UnregisterHandle (File fd)

File	anonymous_namespace{my_winfile.cc}::FileIndex (HANDLE handle)

LARGE_INTEGER	anonymous_namespace{my_winfile.cc}::MakeLargeInteger (int64_t src)

OVERLAPPED	anonymous_namespace{my_winfile.cc}::MakeOverlapped (DWORD l, DWORD h)

OVERLAPPED	anonymous_namespace{my_winfile.cc}::MakeOverlapped (int64_t src)

File	anonymous_namespace{my_winfile.cc}::my_win_sopen (const char *path, int oflag, int shflag, int pmode)
	Open a file with sharing. More...

File	anonymous_namespace{my_winfile.cc}::my_get_stdfile_descriptor (FILE *stream)

HANDLE	my_get_osfhandle (File fd)
	Return the Windows HANDLE for a file descriptor obtained from RegisterHandle(). More...

File	my_win_open (const char *path, int mode)
	Homegrown posix emulation for Windows. More...

int	my_win_close (File fd)
	Homegrown posix emulation for Windows. More...

int64_t	my_win_pread (File fd, uchar *buffer, size_t count, int64_t offset)
	Homegrown posix emulation for Windows. More...

int64_t	my_win_pwrite (File fd, const uchar *buffer, size_t count, int64_t offset)
	Homegrown posix emulation for Windows. More...

int64_t	my_win_lseek (File fd, int64_t pos, int whence)
	Homegrown posix emulation for Windows. More...

int64_t	my_win_write (File fd, const uchar *Buffer, size_t Count)
	Homegrown posix emulation for Windows. More...

int	my_win_chsize (File fd, int64_t newlength)
	Homegrown posix emulation for Windows. More...

File	my_win_fileno (FILE *stream)
	Homegrown posix emulation for Windows. More...

FILE *	my_win_fopen (const char filename, const char mode)
	Homegrown posix emulation for Windows. More...

FILE *	my_win_fdopen (File fd, const char *mode)
	Homegrown posix emulation for Windows. More...

int	my_win_fclose (FILE *stream)
	Homegrown posix emulation for Windows. More...

FILE *	my_win_freopen (const char path, const char mode, FILE *stream)
	Homegrown posix emulation for Windows. More...

int	my_win_fstat (File fd, struct _stati64 *buf)
	Homegrown posix emulation for Windows. More...

int	my_win_stat (const char path, struct _stati64 buf)
	Homegrown posix emulation for Windows. More...

int	my_win_fsync (File fd)
	Homegrown posix emulation for Windows. More...

void	MyWinfileInit ()
	Constructs static objects. More...

void	MyWinfileEnd ()
	Destroys static objects. More...

Variables
HandleInfoVector *	anonymous_namespace{my_winfile.cc}::hivp = nullptr

Detailed Description

The purpose of this file is to provide implementation of file IO routines on Windows that can be thought as drop-in replacement for corresponding C runtime functionality.

Compared to Windows CRT, this one

does not have the same file descriptor limitation (default is 16384 and can be increased further, whereas CRT poses a hard limit of 2048 file descriptors)
the file operations are not serialized
positional IO pread/pwrite is ported here.
no text mode for files, all IO is "binary"

Naming convention: All routines are prefixed with my_win_, e.g Posix open() is implemented with my_win_open()

Implemented are

POSIX routines(e.g open, read, lseek ...)
Some ANSI C stream routines (fopen, fdopen, fileno, fclose)
Windows CRT equivalents (my_get_osfhandle, open_osfhandle)

Worth to note:

File descriptors used here are located in a range that is not compatible with CRT on purpose. Attempt to use a file descriptor from Windows CRT library range in my_win_* function will be punished with assert()
File streams (FILE *) are actually from the C runtime. The routines provided here are useful only in scenarios that use low-level IO with my_win_fileno()

Function Documentation

◆ my_get_osfhandle()

HANDLE my_get_osfhandle ( File fd )

Return the Windows HANDLE for a file descriptor obtained from RegisterHandle().

Parameters

fd	"file descriptor" index into HandleInfoVector.

Return values

handle	corresponding to fd, if found
INVALID_HANDLE_VALUE,if	fd is not valid (illegal index into HandleInfoVector). In this case SetLastError(ERROR_INVALID_HANDLE) will have been called.

◆ my_win_chsize()

int my_win_chsize	(	File	fd,
		int64_t	newlength
	)

Homegrown posix emulation for Windows.

Parameters

fd	"File descriptor" (index into mapping vector).
newlength	new desired length.

Return values

0	if successful.
-1	in case of errors. errno and/or LastError set to indicate the error.

◆ my_win_close()

int my_win_close ( File fd )

Homegrown posix emulation for Windows.

Parameters

fd	"File descriptor" (index into mapping vector).

Return values

0	if successful.
-1	in case of errors. errno and/or LastError set to indicate the error.

◆ my_win_fclose()

int my_win_fclose ( FILE * stream )

Homegrown posix emulation for Windows.

Parameters

stream FILE stream to close.

Note: Calls to my_fileno() and UnregsterHandle() would not be necessary if pseudo fds were not allocated for streams.

Return values

0	if successful.
-1	in case of errors. errno and/or LastError set to indicate the error.

◆ my_win_fdopen()

FILE * my_win_fdopen	(	File	fd,
		const char *	mode
	)

Homegrown posix emulation for Windows.

Parameters

fd	"File descriptor" (index into mapping vector).
mode	File access mode string.

Note: Currently only used in ibd2sdi to bind the fd for a temporary file to a file stream. Could possibly be replaced with tmpfile_s.

Return values

FILE	stream associated with given file descriptor, if successful.
nullptr	in case of errors. errno and/or LastError set to indicate the error.

◆ my_win_fileno()

File my_win_fileno ( FILE * stream )

Homegrown posix emulation for Windows.

Parameters

stream FILE stream to get fd for.

Note: Returned fd can either be a CRT standard fd (stdin stdout or stderr), or a pseudo fd which is an index into the mapping vector).

Return values

Valid	"file descriptor" if successful.
-1	in case of errors. errno and/or LastError set to indicate the error.

◆ my_win_fopen()

FILE * my_win_fopen	(	const char *	filename,
		const char *	mode
	)

Homegrown posix emulation for Windows.

Parameters

filename	File name.
mode	File access mode string.

Return values

FILE	stream associated with given file name, if successful.
nullptr	in case of errors. errno and/or LastError set to indicate the error.

◆ my_win_freopen()

FILE * my_win_freopen	(	const char *	path,
		const char *	mode,
		FILE *	stream
	)

Homegrown posix emulation for Windows.

Parameters

path	File name.
mode	File access mode string
stream	Existing stream to reopen

Note: C11 includes freopen_s. If pseudo fds did not have to be created for streams it would probably be sufficient to just forward to freopen_s.

Return values

valid	FILE stream if successful.
nullptr	in case of errors. errno and/or LastError set to indicate the error.

◆ my_win_fstat()

int my_win_fstat	(	File	fd,
		struct _stati64 *	buf
	)

Homegrown posix emulation for Windows.

Quick and dirty implementation for Windows. Use CRT fstat on temporarily allocated file descriptor. Patch file size, because size that fstat returns is not reliable (may be outdated).

Parameters

	fd	"File descriptor" (index into mapping vector).
[out]	buf	Area to store stat information in.

Return values

0	if successful.
-1	in case of errors. errno and/or LastError set to indicate the error.

◆ my_win_fsync()

int my_win_fsync ( File fd )

Homegrown posix emulation for Windows.

Parameters

fd	"File descriptor" (index into mapping vector).

Return values

0	if successful.
-1	in case of errors. errno and/or LastError set to indicate the error.

◆ my_win_lseek()

int64_t my_win_lseek	(	File	fd,
		int64_t	pos,
		int	whence
	)

Homegrown posix emulation for Windows.

Parameters

fd	"File descriptor" (index into mapping vector).
pos	Offset to seek.
whence	Where to seek from.

Return values

New	offset into file, if successful.
-1	in case of errors. errno and/or LastError set to indicate the error.

◆ my_win_open()

File my_win_open	(	const char *	path,
		int	mode
	)

Homegrown posix emulation for Windows.

Parameters

path	File name.
mode	File access mode string.

Return values

valid	"file descriptor" (actually index into mapping vector) if successful.
-1	in case of errors. errno and/or LastError set to indicate the error.

◆ my_win_pread()

int64_t my_win_pread	(	File	fd,
		uchar *	buffer,
		size_t	count,
		int64_t	offset
	)

Homegrown posix emulation for Windows.

Implements BOTH posix read() and posix pread(). To read from the current file position (like posix read() supply an offset argument that is -1.

Parameters

fd	"File descriptor" (index into mapping vector).
buffer	Destination buffer.
count	Number of bytes to read.
offset	Offset where read starts. -1 to read from the current file position.

Note: ERROR_HANDLE_EOF and ERROR_BROKEN_PIPE are treated as success (returns 0, but with LastError set).

Return values

Number	of bytes read, if successful.
-1	in case of errors. errno and/or LastError set to indicate the error.

◆ my_win_pwrite()

int64_t my_win_pwrite	(	File	fd,
		const uchar *	buffer,
		size_t	count,
		int64_t	offset
	)

Homegrown posix emulation for Windows.

Parameters

fd	"File descriptor" (index into mapping vector).
buffer	Source buffer.
count	Number of bytes to write.
offset	Where to start the write.

Return values

Number	of bytes written, if successful.
-1	in case of errors. errno and/or LastError set to indicate the error.

◆ my_win_stat()

int my_win_stat	(	const char *	path,
		struct _stati64 *	buf
	)

Homegrown posix emulation for Windows.

Parameters

	path	File name to obtain information about.
[out]	buf	Area to store stat information in.

Return values

Valid	"file descriptor" (actually index into mapping vector) if successful.
-1	in case of errors. errno and/or LastError set to indicate the error.

◆ my_win_write()

int64_t my_win_write	(	File	fd,
		const uchar *	Buffer,
		size_t	Count
	)

Homegrown posix emulation for Windows.

Parameters

fd	"File descriptor" (index into mapping vector).
Buffer	Source Bytes.
Count	Number of bytes to write.

Return values

Number	of bytes written, if successful.
-1	in case of errors. errno and/or LastError set to indicate the error.

◆ MyWinfileEnd()

void MyWinfileEnd ( )

Destroys static objects.

◆ MyWinfileInit()

void MyWinfileInit ( )

Constructs static objects.

Classes

Namespaces

Typedefs

Functions

Variables

Detailed Description

Function Documentation

◆ my_get_osfhandle()

◆ my_win_chsize()

◆ my_win_close()

◆ my_win_fclose()

◆ my_win_fdopen()

◆ my_win_fileno()

◆ my_win_fopen()

◆ my_win_freopen()

◆ my_win_fstat()

◆ my_win_fsync()

◆ my_win_lseek()

◆ my_win_open()

◆ my_win_pread()

◆ my_win_pwrite()

◆ my_win_stat()

◆ my_win_write()

◆ MyWinfileEnd()

◆ MyWinfileInit()