YugabyteDB (2.13.0.0-b42, bfc6a6643e7399ac8a0e81d06a3ee6d6571b33ab)

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#include "yb/server/logical_clock.h"

#include "yb/gutil/bind.h"

#include "yb/util/metrics.h"

#include "yb/util/monotime.h"

#include "yb/util/status.h"

#include "yb/util/atomic.h"

namespace yb {

namespace server {

METRIC_DEFINE_gauge_uint64(server, logical_clock_hybrid_time,

                           "Logical Clock Hybrid Time",

                           yb::MetricUnit::kUnits,

                           "Logical clock hybrid time.");

using base::subtle::Atomic64;

using base::subtle::Barrier_AtomicIncrement;

using base::subtle::NoBarrier_CompareAndSwap;

Status LogicalClock::Init() {

  return Status::OK();

}

HybridTimeRange LogicalClock::NowRange() {

  auto result = HybridTime(++now_);

  return std::make_pair(result, result);

}

HybridTime LogicalClock::Peek() {

  return HybridTime(now_.load(std::memory_order_acquire));

}

void LogicalClock::Update(const HybridTime& to_update) {

  if (to_update.is_valid()) {

    UpdateAtomicMax(&now_, to_update.value());

  }

}

LogicalClock* LogicalClock::CreateStartingAt(const HybridTime& hybrid_time) {

  // initialize at 'hybrid_time' - 1 so that the  first output value is 'hybrid_time'.

  return new LogicalClock(hybrid_time.value() - 1);

}

uint64_t LogicalClock::NowForMetrics() {

  // We don't want reading metrics to change the clock.

  return now_.load(std::memory_order_acquire);

}

void LogicalClock::RegisterMetrics(const scoped_refptr<MetricEntity>& metric_entity) {

  METRIC_logical_clock_hybrid_time.InstantiateFunctionGauge(

      metric_entity,

      Bind(&LogicalClock::NowForMetrics, Unretained(this)))

    ->AutoDetachToLastValue(&metric_detacher_);

}

}  // namespace server

}  // namespace yb