Refactor local time getter functions (#12221)

This commit introduces mt_localtime() in src/gettime.h, a wrapper
around the OS-specific thread-safe versions of localtime()
(resp. localtime_s on Windows and localtime_r in other systems).

Per the Open Group recommendation,
«portable applications should call tzset() explicitly before using
ctime_r() or localtime_r() because setting timezone information is
optional for those functions», so we also do a one-shot
call of tzset() (_tzset() on Windows to avoid warning C4996).

The function is used to replace the localtime() calls in
getTimestamp() and makeScreenshot().

(The only reminaing call to localtime() in the tree now is the one in
the local copy of the Lua source code.)
This commit is contained in:
Oblomov 2022-04-28 18:53:33 +02:00 committed by GitHub
parent 7e18a1f1be
commit 0d91ef78dd
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 29 additions and 8 deletions

@ -1810,11 +1810,10 @@ void Client::makeScreenshot()
if (!raw_image)
return;
time_t t = time(NULL);
struct tm *tm = localtime(&t);
const struct tm tm = mt_localtime();
char timetstamp_c[64];
strftime(timetstamp_c, sizeof(timetstamp_c), "%Y%m%d_%H%M%S", tm);
strftime(timetstamp_c, sizeof(timetstamp_c), "%Y%m%d_%H%M%S", &tm);
std::string screenshot_dir;

@ -21,6 +21,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
#include <ctime>
#include <string>
#include <mutex>
enum TimePrecision
{
@ -30,13 +31,34 @@ enum TimePrecision
PRECISION_NANO
};
inline struct tm mt_localtime()
{
// initialize the time zone on first invocation
static std::once_flag tz_init;
std::call_once(tz_init, [] {
#ifdef _WIN32
_tzset();
#else
tzset();
#endif
});
struct tm ret;
time_t t = time(NULL);
// TODO we should check if the function returns NULL, which would mean error
#ifdef _WIN32
localtime_s(&ret, &t);
#else
localtime_r(&t, &ret);
#endif
return ret;
}
inline std::string getTimestamp()
{
time_t t = time(NULL);
// This is not really thread-safe but it won't break anything
// except its own output, so just go with it.
struct tm *tm = localtime(&t);
const struct tm tm = mt_localtime();
char cs[20]; // YYYY-MM-DD HH:MM:SS + '\0'
strftime(cs, 20, "%Y-%m-%d %H:%M:%S", tm);
strftime(cs, 20, "%Y-%m-%d %H:%M:%S", &tm);
return cs;
}