bootstat: Remove custom uptime parser in favor of elapsedRealtime.

Refactored init/utils/boot_clock into base/chrono_utils.

Bug: 34352037
Test: none
Change-Id: Ied0c00867336b85922369d7ff37520e3d28fc61e
diff --git a/bootstat/Android.bp b/bootstat/Android.bp
index d98a9d7..7d9d7a2 100644
--- a/bootstat/Android.bp
+++ b/bootstat/Android.bp
@@ -17,7 +17,6 @@
 bootstat_lib_src_files = [
     "boot_event_record_store.cpp",
     "histogram_logger.cpp",
-    "uptime_parser.cpp",
 ]
 
 cc_defaults {
diff --git a/bootstat/boot_event_record_store.cpp b/bootstat/boot_event_record_store.cpp
index f902af3..8babf1a 100644
--- a/bootstat/boot_event_record_store.cpp
+++ b/bootstat/boot_event_record_store.cpp
@@ -20,14 +20,18 @@
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <utime.h>
+
+#include <chrono>
 #include <cstdlib>
 #include <string>
 #include <utility>
+
+#include <android-base/chrono_utils.h>
 #include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/parseint.h>
+
 #include "histogram_logger.h"
-#include "uptime_parser.h"
 
 namespace {
 
@@ -56,7 +60,9 @@
 }
 
 void BootEventRecordStore::AddBootEvent(const std::string& event) {
-  AddBootEventWithValue(event, bootstat::ParseUptime());
+  auto uptime = std::chrono::duration_cast<std::chrono::seconds>(
+      android::base::boot_clock::now().time_since_epoch());
+  AddBootEventWithValue(event, uptime.count());
 }
 
 // The implementation of AddBootEventValue makes use of the mtime file
diff --git a/bootstat/boot_event_record_store_test.cpp b/bootstat/boot_event_record_store_test.cpp
index 90f6513..0df6706 100644
--- a/bootstat/boot_event_record_store_test.cpp
+++ b/bootstat/boot_event_record_store_test.cpp
@@ -21,15 +21,18 @@
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <unistd.h>
+
+#include <chrono>
 #include <cstdint>
 #include <cstdlib>
+
+#include <android-base/chrono_utils.h>
 #include <android-base/file.h>
 #include <android-base/logging.h>
 #include <android-base/test_utils.h>
 #include <android-base/unique_fd.h>
 #include <gtest/gtest.h>
 #include <gmock/gmock.h>
-#include "uptime_parser.h"
 
 using testing::UnorderedElementsAreArray;
 
@@ -89,6 +92,12 @@
   rmdir(path.c_str());
 }
 
+// Returns the time in seconds since boot.
+time_t GetUptimeSeconds() {
+  return std::chrono::duration_cast<std::chrono::seconds>(
+      android::base::boot_clock::now().time_since_epoch()).count();
+}
+
 class BootEventRecordStoreTest : public ::testing::Test {
  public:
   BootEventRecordStoreTest() {
@@ -126,7 +135,7 @@
   BootEventRecordStore store;
   store.SetStorePath(GetStorePathForTesting());
 
-  time_t uptime = bootstat::ParseUptime();
+  time_t uptime = GetUptimeSeconds();
   ASSERT_NE(-1, uptime);
 
   store.AddBootEvent("cenozoic");
@@ -141,7 +150,7 @@
   BootEventRecordStore store;
   store.SetStorePath(GetStorePathForTesting());
 
-  time_t uptime = bootstat::ParseUptime();
+  time_t uptime = GetUptimeSeconds();
   ASSERT_NE(-1, uptime);
 
   store.AddBootEvent("cretaceous");
diff --git a/bootstat/bootstat.cpp b/bootstat/bootstat.cpp
index c85667e..322add3 100644
--- a/bootstat/bootstat.cpp
+++ b/bootstat/bootstat.cpp
@@ -21,6 +21,7 @@
 #include <getopt.h>
 #include <unistd.h>
 
+#include <chrono>
 #include <cmath>
 #include <cstddef>
 #include <cstdio>
@@ -31,6 +32,7 @@
 #include <vector>
 
 #include <android/log.h>
+#include <android-base/chrono_utils.h>
 #include <android-base/logging.h>
 #include <android-base/parseint.h>
 #include <android-base/strings.h>
@@ -38,7 +40,6 @@
 
 #include "boot_event_record_store.h"
 #include "histogram_logger.h"
-#include "uptime_parser.h"
 
 namespace {
 
@@ -247,7 +248,8 @@
   BootEventRecordStore boot_event_store;
   BootEventRecordStore::BootEventRecord record;
 
-  time_t uptime = bootstat::ParseUptime();
+  auto uptime = std::chrono::duration_cast<std::chrono::seconds>(
+      android::base::boot_clock::now().time_since_epoch());
   time_t current_time_utc = time(nullptr);
 
   if (boot_event_store.GetBootEvent("last_boot_time_utc", &record)) {
@@ -274,22 +276,22 @@
     // Log the amount of time elapsed until the device is decrypted, which
     // includes the variable amount of time the user takes to enter the
     // decryption password.
-    boot_event_store.AddBootEventWithValue("boot_decryption_complete", uptime);
+    boot_event_store.AddBootEventWithValue("boot_decryption_complete", uptime.count());
 
     // Subtract the decryption time to normalize the boot cycle timing.
-    time_t boot_complete = uptime - record.second;
+    std::chrono::seconds boot_complete = std::chrono::seconds(uptime.count() - record.second);
     boot_event_store.AddBootEventWithValue(boot_complete_prefix + "_post_decrypt",
-                                           boot_complete);
+                                           boot_complete.count());
 
 
   } else {
     boot_event_store.AddBootEventWithValue(boot_complete_prefix + "_no_encryption",
-                                           uptime);
+                                           uptime.count());
   }
 
   // Record the total time from device startup to boot complete, regardless of
   // encryption state.
-  boot_event_store.AddBootEventWithValue(boot_complete_prefix, uptime);
+  boot_event_store.AddBootEventWithValue(boot_complete_prefix, uptime.count());
 
   RecordInitBootTimeProp(&boot_event_store, "ro.boottime.init");
   RecordInitBootTimeProp(&boot_event_store, "ro.boottime.init.selinux");
diff --git a/bootstat/uptime_parser.cpp b/bootstat/uptime_parser.cpp
deleted file mode 100644
index 7c2034c..0000000
--- a/bootstat/uptime_parser.cpp
+++ /dev/null
@@ -1,38 +0,0 @@
-/*
- * Copyright (C) 2016 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 "uptime_parser.h"
-
-#include <time.h>
-#include <cstdlib>
-#include <string>
-#include <android-base/file.h>
-#include <android-base/logging.h>
-
-namespace bootstat {
-
-time_t ParseUptime() {
-  std::string uptime_str;
-  if (!android::base::ReadFileToString("/proc/uptime", &uptime_str)) {
-    PLOG(ERROR) << "Failed to read /proc/uptime";
-    return -1;
-  }
-
-  // Cast intentionally rounds down.
-  return static_cast<time_t>(strtod(uptime_str.c_str(), NULL));
-}
-
-}  // namespace bootstat
\ No newline at end of file
diff --git a/bootstat/uptime_parser.h b/bootstat/uptime_parser.h
deleted file mode 100644
index 756ae9b..0000000
--- a/bootstat/uptime_parser.h
+++ /dev/null
@@ -1,29 +0,0 @@
-/*
- * Copyright (C) 2016 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.
- */
-
-#ifndef UPTIME_PARSER_H_
-#define UPTIME_PARSER_H_
-
-#include <time.h>
-
-namespace bootstat {
-
-// Returns the number of seconds the system has been on since reboot.
-time_t ParseUptime();
-
-}  // namespace bootstat
-
-#endif  // UPTIME_PARSER_H_
\ No newline at end of file