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#ifndef DK4FILEIT_H_INCLUDED
/** Protection against multiple inclusions. */
#define DK4FILEIT_H_INCLUDED 1
/** @file dk4fileit.h File information data type.
The dk4_file_info_t data type and related functions allow to
properly identify a path name as symbolic link on both non-Windows
and Windows systems.
On non-Windows systems calls to stat() and lstat() are used to
retrieve the information.
On Windows systems calls to GetFileAttributes(),
CreateFile()/GetFileInformationByHandle()
and FindFirstFile() are used.
As the involved data types are Windows-specific the windows.h
header file is pulled in by this header.
The Windows functions to retrieve information about files differ:
- GetFileAttributes() returns a DWORD containing bits for
file attributes only.
- From CreateFile()/GetFileInformationByHandle() we can receive
very detailed information.
- From FindFirstFile() we can retrieve some of the information
also provided by CreateFile()/GetFileInformationByHandle(), but
number of links, volume serial number, and file index are not
available.
Unfortunately the functions behave differently: While FindFirstFile()
succeeds for c:/pagefile.sys and other files in the root directory,
GetFileAttributes() and CreateFile()/GetFileInformationByHandle()
fail in non-privileged processes. Some forum messages state that
FindFirstFile() is significantly faster than
CreateFile()/GetFileInformationByHandle(), at least for files on servers.
When called for a symbolic link, FindFirstFile() always returns information
about the link. For CreateFile()/GetFileInformationByHandle() one can
choose whether to obtain information about the or about the target.
So the dk4fileinfo() function attempts GetFileAttributes() and
CreateFile()/GetFileInformationByHandle() first to obtain detailed
information. If these functions fail, the FindFirstFile() function is
used. If only FindFirstFile() returned successfully, the resio
component is set to a non-zero value to indicate that only restricted
information (without number of links, volume serial number, and
file index) is available.
*/
#include "dk4conf.h"
#if DK4_ON_WINDOWS
#ifndef WINDOWS_H_INCLUDED
#include <windows.h>
#define WINDOWS_H_INCLUDED 1
#endif
#endif
#include "dk4statt.h"
/** File information contents found.
*/
enum {
/** Information about the link
from lstat().
*/
DK4_FILE_INFO_CONTENTS_DATA_LINK = 1,
/** Information about the link
target from stat().
*/
DK4_FILE_INFO_CONTENTS_DATA_TARGET = 2
};
/** Choose timestamp to convert to text.
*/
enum {
/** Creation time.
*/
DK4_FILE_INFO_TIME_CREATE = 1,
/** Modification time.
*/
DK4_FILE_INFO_TIME_MODIFY ,
/** Last access time.
*/
DK4_FILE_INFO_TIME_ACCESS
};
/** File information data type.
*/
typedef struct {
int contents; /**< The available contents. */
#if DK4_ON_WINDOWS
BY_HANDLE_FILE_INFORMATION linfo; /**< Information about link. */
BY_HANDLE_FILE_INFORMATION tinfo; /**< Information about target. */
DWORD fattr; /**< Link file attributes. */
DWORD rppnt; /**< Link reparse point tag. */
DWORD resio; /**< Flag: Restricted information. */
#else
dk4_stat_t lstb; /**< Buffer for lstat(). */
dk4_stat_t tstb; /**< Buffer for stat(). */
#endif
} dk4_file_info_t;
#endif
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