Open files with "ab" mode even if truncating.

This commit is contained in:
Graydon Hoare 2021-01-09 00:35:32 -08:00
parent 233e97c5e4
commit b7f24b2456
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@ -29,12 +29,27 @@ SPDLOG_INLINE void file_helper::open(const filename_t &fname, bool truncate)
{
close();
filename_ = fname;
auto *mode = truncate ? SPDLOG_FILENAME_T("wb") : SPDLOG_FILENAME_T("ab");
auto *mode = SPDLOG_FILENAME_T("ab");
auto *trunc_mode = SPDLOG_FILENAME_T("wb");
for (int tries = 0; tries < open_tries_; ++tries)
{
// create containing folder if not exists already.
os::create_dir(os::dir_name(fname));
if (truncate)
{
// Truncate by opening-and-closing a tmp file in "wb" mode, always
// opening the actual log-we-write-to in "ab" mode, since that
// interacts more politely with eternal processes that might
// rotate/truncate the file underneath us.
std::FILE *tmp;
if (os::fopen_s(&tmp, fname, trunc_mode))
{
continue;
}
std::fclose(tmp);
}
if (!os::fopen_s(&fd_, fname, mode))
{
return;