1 files changed, 72 insertions, 0 deletions
diff --git a/gitstatus/src/timer.cc b/gitstatus/src/timer.cc
new file mode 100644
index 00000000..0e9f64e9
--- /dev/null
+++ b/gitstatus/src/timer.cc
@@ -0,0 +1,72 @@
+// Copyright 2019 Roman Perepelitsa.
+//
+// This file is part of GitStatus.
+//
+// GitStatus is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// GitStatus is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with GitStatus. If not, see <https://www.gnu.org/licenses/>.
+
+#include "timer.h"
+
+#include <sys/resource.h>
+#include <sys/time.h>
+#include <time.h>
+
+#include <cmath>
+#include <limits>
+
+#include "check.h"
+#include "logging.h"
+
+namespace gitstatus {
+
+namespace {
+
+double CpuTimeMs() {
+  auto ToMs = [](const timeval& tv) { return 1e3 * tv.tv_sec + 1e-3 * tv.tv_usec; };
+  rusage usage = {};
+  CHECK(getrusage(RUSAGE_SELF, &usage) == 0) << Errno();
+  return ToMs(usage.ru_utime) + ToMs(usage.ru_stime);
+}
+
+double WallTimeMs() {
+  // An attempt to call clock_gettime on an ancient version of MacOS fails at runtime.
+  // It's possible to detect the presence of clock_gettime at runtime but I don't have
+  // an ancient MacOS to test the code. Hence this.
+#ifdef __APPLE__
+  return std::numeric_limits<double>::quiet_NaN();
+#else
+  struct timespec ts;
+  clock_gettime(CLOCK_MONOTONIC, &ts);
+  return 1e3 * ts.tv_sec + 1e-6 * ts.tv_nsec;
+#endif
+}
+
+}  // namespace
+
+void Timer::Start() {
+  cpu_ = CpuTimeMs();
+  wall_ = WallTimeMs();
+}
+
+void Timer::Report(const char* msg) {
+  double cpu = CpuTimeMs() - cpu_;
+  if (std::isnan(wall_)) {
+    LOG(INFO) << "Timing for: " << msg << ": " << cpu << "ms cpu";
+  } else {
+    double wall = WallTimeMs() - wall_;
+    LOG(INFO) << "Timing for: " << msg << ": " << cpu << "ms cpu, " << wall << "ms wall";
+  }
+  Start();
+}
+
+}  // namespace gitstatus