1
0
mirror of https://git.tartarus.org/simon/putty.git synced 2025-01-09 17:38:00 +00:00
putty-source/windows/utils/open_for_write_would_lose_data.c
Simon Tatham 3396c97da9 New library-style 'utils' subdirectories.
Now that the new CMake build system is encouraging us to lay out the
code like a set of libraries, it seems like a good idea to make them
look more _like_ libraries, by putting things into separate modules as
far as possible.

This fixes several previous annoyances in which you had to link
against some object in order to get a function you needed, but that
object also contained other functions you didn't need which included
link-time symbol references you didn't want to have to deal with. The
usual offender was subsidiary supporting programs including misc.c for
some innocuous function and then finding they had to deal with the
requirements of buildinfo().

This big reorganisation introduces three new subdirectories called
'utils', one at the top level and one in each platform subdir. In each
case, the directory contains basically the same files that were
previously placed in the 'utils' build-time library, except that the
ones that were extremely miscellaneous (misc.c, utils.c, uxmisc.c,
winmisc.c, winmiscs.c, winutils.c) have been split up into much
smaller pieces.
2021-04-18 08:18:27 +01:00

39 lines
1.3 KiB
C

/*
* Implementation of open_for_write_would_lose_data for Windows.
*/
#include "putty.h"
bool open_for_write_would_lose_data(const Filename *fn)
{
WIN32_FILE_ATTRIBUTE_DATA attrs;
if (!GetFileAttributesEx(fn->path, GetFileExInfoStandard, &attrs)) {
/*
* Generally, if we don't identify a specific reason why we
* should return true from this function, we return false, and
* let the subsequent attempt to open the file for real give a
* more useful error message.
*/
return false;
}
if (attrs.dwFileAttributes & (FILE_ATTRIBUTE_DEVICE |
FILE_ATTRIBUTE_DIRECTORY)) {
/*
* File is something other than an ordinary disk file, so
* opening it for writing will not cause truncation. (It may
* not _succeed_ either, but that's not our problem here!)
*/
return false;
}
if (attrs.nFileSizeHigh == 0 && attrs.nFileSizeLow == 0) {
/*
* File is zero-length (or may be a named pipe, which
* dwFileAttributes can't tell apart from a regular file), so
* opening it for writing won't truncate any data away because
* there's nothing to truncate anyway.
*/
return false;
}
return true;
}