Update Icing from upstream.

Change-Id: Ic022a44e876a6060a47e0db991e63b2b73807769

1 files changed, 33 insertions, 11 deletions

diff --git a/icing/util/clock.h b/icing/util/clock.h
index a37fe58..06f1c9d 100644
--- a/icing/util/clock.h
+++ b/icing/util/clock.h
@@ -16,21 +16,11 @@
 #define ICING_UTIL_CLOCK_H_
 
 #include <cstdint>
+#include <memory>
 
 namespace icing {
 namespace lib {
 
-// Wrapper around real-time clock functions. This is separated primarily so
-// tests can override this clock and inject it into the class under test.
-class Clock {
- public:
-  virtual ~Clock() = default;
-
-  // Returns the current time in milliseconds, it's guaranteed that the return
-  // value is non-negative.
-  virtual int64_t GetSystemTimeMilliseconds() const;
-};
-
 // Returns the current steady time in nanoseconds. The steady clock is different
 // from the system clock. It's monotonic and never returns a lower value than a
 // previous call, while a system clock can be occasionally adjusted.
@@ -42,6 +32,38 @@ int64_t GetSteadyTimeNanoseconds();
 // adjusted.
 int64_t GetSteadyTimeMilliseconds();
 
+// Used to calculate the elapsed time.
+class Timer {
+ public:
+  // Creates and starts the timer.
+  Timer() : start_timestamp_milliseconds_(GetSteadyTimeMilliseconds()) {}
+
+  virtual ~Timer() = default;
+
+  // Returns the elapsed time from when timer started.
+  virtual int64_t GetElapsedMilliseconds() {
+    return GetSteadyTimeMilliseconds() - start_timestamp_milliseconds_;
+  }
+
+ private:
+  int64_t start_timestamp_milliseconds_;
+};
+
+// Wrapper around real-time clock functions. This is separated primarily so
+// tests can override this clock and inject it into the class under test.
+class Clock {
+ public:
+  virtual ~Clock() = default;
+
+  // Returns the current time in milliseconds, it's guaranteed that the return
+  // value is non-negative.
+  virtual int64_t GetSystemTimeMilliseconds() const;
+
+  // Returns a timer used to calculate the elapsed time. The timer starts when
+  // the method returns.
+  virtual std::unique_ptr<Timer> GetNewTimer() const;
+};
+
 }  // namespace lib
 }  // namespace icing