From fe5ca9dad97b9c9cfa4f81fd25b493b0082ee827 Mon Sep 17 00:00:00 2001
From: Stefan Weil <sw@weilnetz.de>
Date: Thu, 5 Aug 2021 10:30:57 +0200
Subject: [PATCH] unittest: Remove dependency on absl::GetCurrentTimeNanos()

Signed-off-by: Stefan Weil <sw@weilnetz.de>
---
 Makefile.am           |  4 ----
 unittest/cycletimer.h | 19 ++++++++++---------
 2 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/Makefile.am b/Makefile.am
index 7c6b5393..23391b88 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1173,13 +1173,11 @@ libgtest_main_la_CPPFLAGS = $(libgtest_la_CPPFLAGS)
 # Build Abseil (needed for some unit tests).
 check_LTLIBRARIES += libabseil.la
 libabseil_la_SOURCES =
-libabseil_la_SOURCES += abseil/absl/base/internal/cycleclock.cc
 libabseil_la_SOURCES += abseil/absl/base/internal/raw_logging.cc
 libabseil_la_SOURCES += abseil/absl/base/internal/spinlock.cc
 libabseil_la_SOURCES += abseil/absl/base/internal/spinlock_wait.cc
 libabseil_la_SOURCES += abseil/absl/base/internal/sysinfo.cc
 libabseil_la_SOURCES += abseil/absl/base/internal/throw_delegate.cc
-libabseil_la_SOURCES += abseil/absl/base/internal/unscaledcycleclock.cc
 libabseil_la_SOURCES += abseil/absl/numeric/int128.cc
 libabseil_la_SOURCES += abseil/absl/strings/ascii.cc
 libabseil_la_SOURCES += abseil/absl/strings/charconv.cc
@@ -1197,8 +1195,6 @@ libabseil_la_SOURCES += abseil/absl/strings/numbers.cc
 libabseil_la_SOURCES += abseil/absl/strings/str_cat.cc
 libabseil_la_SOURCES += abseil/absl/strings/str_split.cc
 libabseil_la_SOURCES += abseil/absl/strings/string_view.cc
-libabseil_la_SOURCES += abseil/absl/time/clock.cc
-libabseil_la_SOURCES += abseil/absl/time/duration.cc
 libabseil_la_CPPFLAGS = -I$(top_srcdir)/abseil
 
 GMOCK_INCLUDES = -I$(top_srcdir)/googletest/googlemock/include \
diff --git a/unittest/cycletimer.h b/unittest/cycletimer.h
index 6a61a86b..65947fd1 100644
--- a/unittest/cycletimer.h
+++ b/unittest/cycletimer.h
@@ -13,10 +13,16 @@
 #ifndef TESSERACT_UNITTEST_CYCLETIMER_H
 #define TESSERACT_UNITTEST_CYCLETIMER_H
 
-#include "absl/time/clock.h" // for GetCurrentTimeNanos
+#include <chrono> // for std::chrono
 
 // See https://github.com/google/or-tools/blob/master/ortools/base/timer.h
 class CycleTimer {
+private:
+  static int64_t now() {
+    return std::chrono::duration_cast<std::chrono::milliseconds>(
+      std::chrono::steady_clock::now().time_since_epoch()).count();
+  }
+
 public:
   CycleTimer() {
     Reset();
@@ -31,7 +37,7 @@ public:
   // When Start() is called multiple times, only the most recent is used.
   void Start() {
     running_ = true;
-    start_ = absl::GetCurrentTimeNanos();
+    start_ = now();
   }
 
   void Restart() {
@@ -41,17 +47,12 @@ public:
 
   void Stop() {
     if (running_) {
-      sum_ += absl::GetCurrentTimeNanos() - start_;
+      sum_ += now() - start_;
       running_ = false;
     }
   }
   int64_t GetInMs() const {
-    return GetNanos() / 1000000;
-  }
-
-protected:
-  int64_t GetNanos() const {
-    return running_ ? absl::GetCurrentTimeNanos() - start_ + sum_ : sum_;
+    return running_ ? now() - start_ + sum_ : sum_;
   }
 
 private: