refactor: use std::chrono not OS-specific syscalls (#2554)

libtransmission/log.cc

@@ -127,8 +127,7 @@ void tr_logFreeQueue(tr_log_message* list)
 
 char* tr_logGetTimeStr(char* buf, size_t buflen)
 {
-    struct timeval tv;
-    tr_gettimeofday(&tv);
+    auto const tv = tr_gettimeofday();
     time_t const seconds = tv.tv_sec;
     auto const milliseconds = int(tv.tv_usec / 1000);
     char msec_str[8];

libtransmission/session.cc

@@ -676,8 +676,7 @@ static void onNowTimer(evutil_socket_t /*fd*/, short /*what*/, void* vsession)
     **/
 
     /* schedule the next timer for right after the next second begins */
-    struct timeval tv;
-    tr_gettimeofday(&tv);
+    auto const tv = tr_gettimeofday();
     int constexpr Min = 100;
     int constexpr Max = 999999;
     int const usec = std::clamp(int(1000000 - tv.tv_usec), Min, Max);

libtransmission/tr-dht.cc

@@ -815,8 +815,8 @@ int dht_sendto(int sockfd, void const* buf, int len, int flags, struct sockaddr
 extern "C" int dht_gettimeofday(struct timeval* tv, struct timezone* tz)
 {
     TR_ASSERT(tz == nullptr);
-
-    return tr_gettimeofday(tv);
+    *tv = tr_gettimeofday();
+    return 0;
 }
 
 #endif

libtransmission/utils.cc

@@ -8,6 +8,7 @@
 #include <cctype> /* isdigit() */
 #include <cerrno>
 #include <cfloat> // DBL_DIG
+#include <chrono>
 #include <clocale> // localeconv()
 #include <cstdint> // SIZE_MAX
 #include <cstdlib> // getenv()
@@ -20,9 +21,10 @@
 #include <vector>
 
 #ifdef _WIN32
-#include <ws2tcpip.h> /* WSAStartup() */
-#include <windows.h> /* Sleep(), GetSystemTimeAsFileTime(), GetEnvironmentVariable() */
+#include <windows.h> /* Sleep(), GetEnvironmentVariable() */
+
 #include <shellapi.h> /* CommandLineToArgv() */
+#include <ws2tcpip.h> /* WSAStartup() */
 #endif
 
 #ifdef HAVE_ICONV
@@ -102,40 +104,14 @@ struct tm* tr_localtime_r(time_t const* timep, struct tm* result)
 #endif
 }
 
-int tr_gettimeofday(struct timeval* tv)
+struct timeval tr_gettimeofday()
 {
-#ifdef _WIN32
-
-#define DELTA_EPOCH_IN_MICROSECS 11644473600000000ULL
-
-    FILETIME ft;
-    uint64_t tmp = 0;
-
-    if (tv == nullptr)
-    {
-        errno = EINVAL;
-        return -1;
-    }
-
-    GetSystemTimeAsFileTime(&ft);
-    tmp |= ft.dwHighDateTime;
-    tmp <<= 32;
-    tmp |= ft.dwLowDateTime;
-    tmp /= 10; /* to microseconds */
-    tmp -= DELTA_EPOCH_IN_MICROSECS;
-
-    tv->tv_sec = tmp / 1000000UL;
-    tv->tv_usec = tmp % 1000000UL;
-
-    return 0;
-
-#undef DELTA_EPOCH_IN_MICROSECS
-
-#else
-
-    return gettimeofday(tv, nullptr);
-
-#endif
+    auto const d = std::chrono::system_clock::now().time_since_epoch();
+    auto const s = std::chrono::duration_cast<std::chrono::seconds>(d);
+    auto ret = timeval{};
+    ret.tv_sec = s.count();
+    ret.tv_usec = std::chrono::duration_cast<std::chrono::microseconds>(d - s).count();
+    return ret;
 }
 
 /***
@@ -554,10 +530,8 @@ bool tr_str_has_suffix(char const* str, char const* suffix)
 
 uint64_t tr_time_msec()
 {
-    struct timeval tv;
-
-    tr_gettimeofday(&tv);
-    return (uint64_t)tv.tv_sec * 1000 + (tv.tv_usec / 1000);
+    auto const tv = tr_gettimeofday();
+    return uint64_t(tv.tv_sec) * 1000 + (tv.tv_usec / 1000);
 }
 
 void tr_wait_msec(long int msec)

libtransmission/utils.h

@@ -425,7 +425,7 @@ struct tm* tr_localtime_r(time_t const* _clock, struct tm* _result);
 struct tm* tr_gmtime_r(time_t const* _clock, struct tm* _result);
 
 /** @brief Portability wrapper for gettimeofday(), with tz argument dropped */
-int tr_gettimeofday(struct timeval* tv);
+struct timeval tr_gettimeofday();
 
 /**
  * @brief move a file