From e6918187568dbd01842d8d1d2c808ce16a894239 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sun, 21 Apr 2024 13:54:28 +0200
Subject: Adding upstream version 18.2.2.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 src/rocksdb/env/emulated_clock.h | 114 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 114 insertions(+)
 create mode 100644 src/rocksdb/env/emulated_clock.h

(limited to 'src/rocksdb/env/emulated_clock.h')

diff --git a/src/rocksdb/env/emulated_clock.h b/src/rocksdb/env/emulated_clock.h
new file mode 100644
index 000000000..622737635
--- /dev/null
+++ b/src/rocksdb/env/emulated_clock.h
@@ -0,0 +1,114 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+#pragma once
+
+#include <atomic>
+#include <string>
+
+#include "rocksdb/status.h"
+#include "rocksdb/system_clock.h"
+
+namespace ROCKSDB_NAMESPACE {
+// A SystemClock that can "mock" sleep and counts its operations.
+class EmulatedSystemClock : public SystemClockWrapper {
+ private:
+  // Something to return when mocking current time
+  const int64_t maybe_starting_time_;
+  std::atomic<int> sleep_counter_{0};
+  std::atomic<int> cpu_counter_{0};
+  std::atomic<int64_t> addon_microseconds_{0};
+  // Do not modify in the env of a running DB (could cause deadlock)
+  std::atomic<bool> time_elapse_only_sleep_;
+  bool no_slowdown_;
+
+ public:
+  explicit EmulatedSystemClock(const std::shared_ptr<SystemClock>& base,
+                               bool time_elapse_only_sleep = false);
+
+  static const char* kClassName() { return "TimeEmulatedSystemClock"; }
+  const char* Name() const override { return kClassName(); }
+
+  virtual void SleepForMicroseconds(int micros) override {
+    sleep_counter_++;
+    if (no_slowdown_ || time_elapse_only_sleep_) {
+      addon_microseconds_.fetch_add(micros);
+    }
+    if (!no_slowdown_) {
+      SystemClockWrapper::SleepForMicroseconds(micros);
+    }
+  }
+
+  void MockSleepForMicroseconds(int64_t micros) {
+    sleep_counter_++;
+    assert(no_slowdown_);
+    addon_microseconds_.fetch_add(micros);
+  }
+
+  void MockSleepForSeconds(int64_t seconds) {
+    sleep_counter_++;
+    assert(no_slowdown_);
+    addon_microseconds_.fetch_add(seconds * 1000000);
+  }
+
+  void SetTimeElapseOnlySleep(bool enabled) {
+    // We cannot set these before destroying the last DB because they might
+    // cause a deadlock or similar without the appropriate options set in
+    // the DB.
+    time_elapse_only_sleep_ = enabled;
+    no_slowdown_ = enabled;
+  }
+
+  bool IsTimeElapseOnlySleep() const { return time_elapse_only_sleep_.load(); }
+  void SetMockSleep(bool enabled = true) { no_slowdown_ = enabled; }
+  bool IsMockSleepEnabled() const { return no_slowdown_; }
+
+  int GetSleepCounter() const { return sleep_counter_.load(); }
+
+  virtual Status GetCurrentTime(int64_t* unix_time) override {
+    Status s;
+    if (time_elapse_only_sleep_) {
+      *unix_time = maybe_starting_time_;
+    } else {
+      s = SystemClockWrapper::GetCurrentTime(unix_time);
+    }
+    if (s.ok()) {
+      // mock microseconds elapsed to seconds of time
+      *unix_time += addon_microseconds_.load() / 1000000;
+    }
+    return s;
+  }
+
+  virtual uint64_t CPUNanos() override {
+    cpu_counter_++;
+    return SystemClockWrapper::CPUNanos();
+  }
+
+  virtual uint64_t CPUMicros() override {
+    cpu_counter_++;
+    return SystemClockWrapper::CPUMicros();
+  }
+
+  virtual uint64_t NowNanos() override {
+    return (time_elapse_only_sleep_ ? 0 : SystemClockWrapper::NowNanos()) +
+           addon_microseconds_.load() * 1000;
+  }
+
+  virtual uint64_t NowMicros() override {
+    return (time_elapse_only_sleep_ ? 0 : SystemClockWrapper::NowMicros()) +
+           addon_microseconds_.load();
+  }
+
+  int GetCpuCounter() const { return cpu_counter_.load(); }
+
+  void ResetCounters() {
+    cpu_counter_.store(0);
+    sleep_counter_.store(0);
+  }
+};
+}  // namespace ROCKSDB_NAMESPACE
-- 
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