bootstat: Refactor init/utils/boot_clock into base/chrono_utils.

Use this for bootstat and init. This replaces the custom uptime parser in
bootstat.

This is a reland of aosp/332854 with a fix for Darwin.

Bug: 34352037
Test: chrono_utils_test
Change-Id: Ib2567d8df0e460ab59753ac1c053dd7f9f1008a7

1 files changed, 47 insertions, 0 deletions

diff --git a/base/chrono_utils_test.cpp b/base/chrono_utils_test.cpp
new file mode 100644
index 000000000..bc6df4b9a
--- /dev/null
+++ b/base/chrono_utils_test.cpp
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "android-base/chrono_utils.h"
+
+#include <time.h>
+
+#include <chrono>
+
+#include <gtest/gtest.h>
+
+namespace android {
+namespace base {
+
+std::chrono::seconds GetBootTimeSeconds() {
+  struct timespec now;
+  clock_gettime(CLOCK_BOOTTIME, &now);
+
+  auto now_tp = boot_clock::time_point(
+      std::chrono::seconds(now.tv_sec) + std::chrono::nanoseconds(now.tv_nsec));
+  return std::chrono::duration_cast<std::chrono::seconds>(
+      now_tp.time_since_epoch());
+}
+
+// Tests (at least) the seconds accuracy of the boot_clock::now() method.
+TEST(ChronoUtilsTest, BootClockNowSeconds) {
+  auto now = GetBootTimeSeconds();
+  auto boot_seconds = std::chrono::duration_cast<std::chrono::seconds>(
+      boot_clock::now().time_since_epoch());
+  EXPECT_EQ(now, boot_seconds);
+}
+
+}  // namespace base
+}  // namespace android
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