Update to current webrtc library

This is from the upstream library commit id
3326535126e435f1ba647885ce43a8f0f3d317eb, corresponding to Chromium
88.0.4290.1.

webrtc/rtc_base/time_utils.cc

@@ -0,0 +1,327 @@
+/*
+ *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <stdint.h>
+
+#if defined(WEBRTC_POSIX)
+#include <sys/time.h>
+#if defined(WEBRTC_MAC)
+#include <mach/mach_time.h>
+#endif
+#endif
+
+#if defined(WEBRTC_WIN)
+// clang-format off
+// clang formatting would put <windows.h> last,
+// which leads to compilation failure.
+#include <windows.h>
+#include <mmsystem.h>
+#include <sys/timeb.h>
+// clang-format on
+#endif
+
+#include "rtc_base/checks.h"
+#include "rtc_base/numerics/safe_conversions.h"
+#include "rtc_base/time_utils.h"
+
+namespace rtc {
+
+ClockInterface* g_clock = nullptr;
+
+ClockInterface* SetClockForTesting(ClockInterface* clock) {
+  ClockInterface* prev = g_clock;
+  g_clock = clock;
+  return prev;
+}
+
+ClockInterface* GetClockForTesting() {
+  return g_clock;
+}
+
+#if defined(WINUWP)
+
+namespace {
+
+class TimeHelper final {
+ public:
+  TimeHelper(const TimeHelper&) = delete;
+
+  // Resets the clock based upon an NTP server. This routine must be called
+  // prior to the main system start-up to ensure all clocks are based upon
+  // an NTP server time if NTP synchronization is required. No critical
+  // section is used thus this method must be called prior to any clock
+  // routines being used.
+  static void SyncWithNtp(int64_t ntp_server_time_ms) {
+    auto& singleton = Singleton();
+    TIME_ZONE_INFORMATION time_zone;
+    GetTimeZoneInformation(&time_zone);
+    int64_t time_zone_bias_ns =
+        rtc::dchecked_cast<int64_t>(time_zone.Bias) * 60 * 1000 * 1000 * 1000;
+    singleton.app_start_time_ns_ =
+        (ntp_server_time_ms - kNTPTimeToUnixTimeEpochOffset) * 1000000 -
+        time_zone_bias_ns;
+    singleton.UpdateReferenceTime();
+  }
+
+  // Returns the number of nanoseconds that have passed since unix epoch.
+  static int64_t TicksNs() {
+    auto& singleton = Singleton();
+    int64_t result = 0;
+    LARGE_INTEGER qpcnt;
+    QueryPerformanceCounter(&qpcnt);
+    result = rtc::dchecked_cast<int64_t>(
+        (rtc::dchecked_cast<uint64_t>(qpcnt.QuadPart) * 100000 /
+         rtc::dchecked_cast<uint64_t>(singleton.os_ticks_per_second_)) *
+        10000);
+    result = singleton.app_start_time_ns_ + result -
+             singleton.time_since_os_start_ns_;
+    return result;
+  }
+
+ private:
+  TimeHelper() {
+    TIME_ZONE_INFORMATION time_zone;
+    GetTimeZoneInformation(&time_zone);
+    int64_t time_zone_bias_ns =
+        rtc::dchecked_cast<int64_t>(time_zone.Bias) * 60 * 1000 * 1000 * 1000;
+    FILETIME ft;
+    // This will give us system file in UTC format.
+    GetSystemTimeAsFileTime(&ft);
+    LARGE_INTEGER li;
+    li.HighPart = ft.dwHighDateTime;
+    li.LowPart = ft.dwLowDateTime;
+
+    app_start_time_ns_ = (li.QuadPart - kFileTimeToUnixTimeEpochOffset) * 100 -
+                         time_zone_bias_ns;
+
+    UpdateReferenceTime();
+  }
+
+  static TimeHelper& Singleton() {
+    static TimeHelper singleton;
+    return singleton;
+  }
+
+  void UpdateReferenceTime() {
+    LARGE_INTEGER qpfreq;
+    QueryPerformanceFrequency(&qpfreq);
+    os_ticks_per_second_ = rtc::dchecked_cast<int64_t>(qpfreq.QuadPart);
+
+    LARGE_INTEGER qpcnt;
+    QueryPerformanceCounter(&qpcnt);
+    time_since_os_start_ns_ = rtc::dchecked_cast<int64_t>(
+        (rtc::dchecked_cast<uint64_t>(qpcnt.QuadPart) * 100000 /
+         rtc::dchecked_cast<uint64_t>(os_ticks_per_second_)) *
+        10000);
+  }
+
+ private:
+  static constexpr uint64_t kFileTimeToUnixTimeEpochOffset =
+      116444736000000000ULL;
+  static constexpr uint64_t kNTPTimeToUnixTimeEpochOffset = 2208988800000L;
+
+  // The number of nanoseconds since unix system epoch
+  int64_t app_start_time_ns_;
+  // The number of nanoseconds since the OS started
+  int64_t time_since_os_start_ns_;
+  // The OS calculated ticks per second
+  int64_t os_ticks_per_second_;
+};
+
+}  // namespace
+
+void SyncWithNtp(int64_t time_from_ntp_server_ms) {
+  TimeHelper::SyncWithNtp(time_from_ntp_server_ms);
+}
+
+#endif  // defined(WINUWP)
+
+int64_t SystemTimeNanos() {
+  int64_t ticks;
+#if defined(WEBRTC_MAC)
+  static mach_timebase_info_data_t timebase;
+  if (timebase.denom == 0) {
+    // Get the timebase if this is the first time we run.
+    // Recommended by Apple's QA1398.
+    if (mach_timebase_info(&timebase) != KERN_SUCCESS) {
+      RTC_NOTREACHED();
+    }
+  }
+  // Use timebase to convert absolute time tick units into nanoseconds.
+  const auto mul = [](uint64_t a, uint32_t b) -> int64_t {
+    RTC_DCHECK_NE(b, 0);
+    RTC_DCHECK_LE(a, std::numeric_limits<int64_t>::max() / b)
+        << "The multiplication " << a << " * " << b << " overflows";
+    return rtc::dchecked_cast<int64_t>(a * b);
+  };
+  ticks = mul(mach_absolute_time(), timebase.numer) / timebase.denom;
+#elif defined(WEBRTC_POSIX)
+  struct timespec ts;
+  // TODO(deadbeef): Do we need to handle the case when CLOCK_MONOTONIC is not
+  // supported?
+  clock_gettime(CLOCK_MONOTONIC, &ts);
+  ticks = kNumNanosecsPerSec * static_cast<int64_t>(ts.tv_sec) +
+          static_cast<int64_t>(ts.tv_nsec);
+#elif defined(WINUWP)
+  ticks = TimeHelper::TicksNs();
+#elif defined(WEBRTC_WIN)
+  static volatile LONG last_timegettime = 0;
+  static volatile int64_t num_wrap_timegettime = 0;
+  volatile LONG* last_timegettime_ptr = &last_timegettime;
+  DWORD now = timeGetTime();
+  // Atomically update the last gotten time
+  DWORD old = InterlockedExchange(last_timegettime_ptr, now);
+  if (now < old) {
+    // If now is earlier than old, there may have been a race between threads.
+    // 0x0fffffff ~3.1 days, the code will not take that long to execute
+    // so it must have been a wrap around.
+    if (old > 0xf0000000 && now < 0x0fffffff) {
+      num_wrap_timegettime++;
+    }
+  }
+  ticks = now + (num_wrap_timegettime << 32);
+  // TODO(deadbeef): Calculate with nanosecond precision. Otherwise, we're
+  // just wasting a multiply and divide when doing Time() on Windows.
+  ticks = ticks * kNumNanosecsPerMillisec;
+#else
+#error Unsupported platform.
+#endif
+  return ticks;
+}
+
+int64_t SystemTimeMillis() {
+  return static_cast<int64_t>(SystemTimeNanos() / kNumNanosecsPerMillisec);
+}
+
+int64_t TimeNanos() {
+  if (g_clock) {
+    return g_clock->TimeNanos();
+  }
+  return SystemTimeNanos();
+}
+
+uint32_t Time32() {
+  return static_cast<uint32_t>(TimeNanos() / kNumNanosecsPerMillisec);
+}
+
+int64_t TimeMillis() {
+  return TimeNanos() / kNumNanosecsPerMillisec;
+}
+
+int64_t TimeMicros() {
+  return TimeNanos() / kNumNanosecsPerMicrosec;
+}
+
+int64_t TimeAfter(int64_t elapsed) {
+  RTC_DCHECK_GE(elapsed, 0);
+  return TimeMillis() + elapsed;
+}
+
+int32_t TimeDiff32(uint32_t later, uint32_t earlier) {
+  return later - earlier;
+}
+
+int64_t TimeDiff(int64_t later, int64_t earlier) {
+  return later - earlier;
+}
+
+TimestampWrapAroundHandler::TimestampWrapAroundHandler()
+    : last_ts_(0), num_wrap_(-1) {}
+
+int64_t TimestampWrapAroundHandler::Unwrap(uint32_t ts) {
+  if (num_wrap_ == -1) {
+    last_ts_ = ts;
+    num_wrap_ = 0;
+    return ts;
+  }
+
+  if (ts < last_ts_) {
+    if (last_ts_ >= 0xf0000000 && ts < 0x0fffffff)
+      ++num_wrap_;
+  } else if ((ts - last_ts_) > 0xf0000000) {
+    // Backwards wrap. Unwrap with last wrap count and don't update last_ts_.
+    return ts + (num_wrap_ - 1) * (int64_t{1} << 32);
+  }
+
+  last_ts_ = ts;
+  return ts + (num_wrap_ << 32);
+}
+
+int64_t TmToSeconds(const tm& tm) {
+  static short int mdays[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
+  static short int cumul_mdays[12] = {0,   31,  59,  90,  120, 151,
+                                      181, 212, 243, 273, 304, 334};
+  int year = tm.tm_year + 1900;
+  int month = tm.tm_mon;
+  int day = tm.tm_mday - 1;  // Make 0-based like the rest.
+  int hour = tm.tm_hour;
+  int min = tm.tm_min;
+  int sec = tm.tm_sec;
+
+  bool expiry_in_leap_year =
+      (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
+
+  if (year < 1970)
+    return -1;
+  if (month < 0 || month > 11)
+    return -1;
+  if (day < 0 || day >= mdays[month] + (expiry_in_leap_year && month == 2 - 1))
+    return -1;
+  if (hour < 0 || hour > 23)
+    return -1;
+  if (min < 0 || min > 59)
+    return -1;
+  if (sec < 0 || sec > 59)
+    return -1;
+
+  day += cumul_mdays[month];
+
+  // Add number of leap days between 1970 and the expiration year, inclusive.
+  day += ((year / 4 - 1970 / 4) - (year / 100 - 1970 / 100) +
+          (year / 400 - 1970 / 400));
+
+  // We will have added one day too much above if expiration is during a leap
+  // year, and expiration is in January or February.
+  if (expiry_in_leap_year && month <= 2 - 1)  // |month| is zero based.
+    day -= 1;
+
+  // Combine all variables into seconds from 1970-01-01 00:00 (except |month|
+  // which was accumulated into |day| above).
+  return (((static_cast<int64_t>(year - 1970) * 365 + day) * 24 + hour) * 60 +
+          min) *
+             60 +
+         sec;
+}
+
+int64_t TimeUTCMicros() {
+  if (g_clock) {
+    return g_clock->TimeNanos() / kNumNanosecsPerMicrosec;
+  }
+#if defined(WEBRTC_POSIX)
+  struct timeval time;
+  gettimeofday(&time, nullptr);
+  // Convert from second (1.0) and microsecond (1e-6).
+  return (static_cast<int64_t>(time.tv_sec) * rtc::kNumMicrosecsPerSec +
+          time.tv_usec);
+
+#elif defined(WEBRTC_WIN)
+  struct _timeb time;
+  _ftime(&time);
+  // Convert from second (1.0) and milliseconds (1e-3).
+  return (static_cast<int64_t>(time.time) * rtc::kNumMicrosecsPerSec +
+          static_cast<int64_t>(time.millitm) * rtc::kNumMicrosecsPerMillisec);
+#endif
+}
+
+int64_t TimeUTCMillis() {
+  return TimeUTCMicros() / kNumMicrosecsPerMillisec;
+}
+
+}  // namespace rtc