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#812: Added function to determine the number of hard links on Windows NTFS. (Thomas Beutlich)

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This commit is contained in:
Andreas Huggel 2012-02-11 03:58:30 +00:00
parent a16b2c0052
commit ffe8209018
1 changed files with 50 additions and 3 deletions
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53
src/basicio.cpp
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@ -61,9 +61,10 @@ EXIV2_RCSID("@(#) $Id$")
# include <unistd.h> // for getpid, stat
#endif
// MSVC doesn't provide mode_t
// MSVC doesn't provide mode_t, nlink_t
#ifdef _MSC_VER
typedef unsigned short mode_t;
typedef short nlink_t;
#endif
#if defined WIN32 && !defined __CYGWIN__
@ -119,7 +120,7 @@ namespace Exiv2 {
StructStat() : st_mode(0), st_size(0), st_nlink(0) {}
mode_t st_mode; //!< Permissions
off_t st_size; //!< Size
nlink_t st_nlink; //!< Number of hard links
nlink_t st_nlink; //!< Number of hard links (broken on Windows, see winNumberOfLinks())
};
// METHODS
@ -132,6 +133,10 @@ namespace Exiv2 {
int switchMode(OpMode opMode);
//! stat wrapper for internal use
int stat(StructStat& buf) const;
#if defined WIN32 && !defined __CYGWIN__
// Windows function to determine the number of hardlinks (on NTFS)
DWORD winNumberOfLinks() const;
#endif
private:
// NOT IMPLEMENTED
@ -249,6 +254,43 @@ namespace Exiv2 {
return ret;
} // FileIo::Impl::stat
#if defined WIN32 && !defined __CYGWIN__
DWORD FileIo::Impl::winNumberOfLinks() const
{
DWORD nlink = 1;
HANDLE hFd = (HANDLE)_get_osfhandle(fileno(fp_));
if (hFd != INVALID_HANDLE_VALUE) {
typedef BOOL (WINAPI * GetFileInformationByHandle_t)(HANDLE, LPBY_HANDLE_FILE_INFORMATION);
HMODULE hKernel = LoadLibrary("kernel32.dll");
if (hKernel) {
GetFileInformationByHandle_t pfcn_GetFileInformationByHandle = (GetFileInformationByHandle_t)GetProcAddress(hKernel, "GetFileInformationByHandle");
if (pfcn_GetFileInformationByHandle) {
BY_HANDLE_FILE_INFORMATION fi = {0};
if (pfcn_GetFileInformationByHandle(hFd, &fi)) {
nlink = fi.nNumberOfLinks;
}
#ifdef DEBUG
else EXV_DEBUG << "GetFileInformationByHandle failed\n";
#endif
}
#ifdef DEBUG
else EXV_DEBUG << "GetProcAddress(hKernel, \"GetFileInformationByHandle\") failed\n";
#endif
FreeLibrary(hKernel);
}
#ifdef DEBUG
else EXV_DEBUG << "LoadLibrary(\"kernel32.dll\") failed\n";
#endif
}
#ifdef DEBUG
else EXV_DEBUG << "_get_osfhandle failed: INVALID_HANDLE_VALUE\n";
#endif
return nlink;
} // FileIo::Impl::winNumberOfLinks
#endif // defined WIN32 && !defined __CYGWIN__
FileIo::FileIo(const std::string& path)
: p_(new Impl(path))
{
@ -447,11 +489,16 @@ namespace Exiv2 {
Impl::StructStat buf;
int ret = p_->stat(buf);
#if defined WIN32 && !defined __CYGWIN__
DWORD nlink = p_->winNumberOfLinks();
#else
nlink_t nlink = buf.st_nlink;
#endif
// If file is > 1MB and doesn't have hard links then use a file, otherwise
// use a memory buffer. I.e., files with hard links always use a memory
// buffer, which is a workaround to ensure that the links don't get broken.
if (ret != 0 || (buf.st_size > 1048576 && buf.st_nlink == 1)) {
if (ret != 0 || (buf.st_size > 1048576 && nlink == 1)) {
pid_t pid = ::getpid();
std::auto_ptr<FileIo> fileIo;
#ifdef EXV_UNICODE_PATH