Bug 1733335 - Add {add,subtract}_microseconds and Clone implementations to ProfilerTime r=emilio

Clone will make the ProfilerTime easier to use. And {add,subtract}_microseconds
implementations are helpful when you need to subtract/add some duration before
adding a marker. There is a similar code in the Webrender marker code, and this
will allow them to use the new API instead of some custom code.

Differential Revision: https://phabricator.services.mozilla.com/D127111

tools/profiler/core/ProfilerBindings.cpp

@@ -38,10 +38,29 @@ void gecko_profiler_construct_timestamp_now(mozilla::TimeStamp* aTimeStamp) {
   new (aTimeStamp) mozilla::TimeStamp(mozilla::TimeStamp::Now());
 }
 
+void gecko_profiler_clone_timestamp(const mozilla::TimeStamp* aSrcTimeStamp,
+                                    mozilla::TimeStamp* aDestTimeStamp) {
+  new (aDestTimeStamp) mozilla::TimeStamp(*aSrcTimeStamp);
+}
+
 void gecko_profiler_destruct_timestamp(mozilla::TimeStamp* aTimeStamp) {
   aTimeStamp->~TimeStamp();
 }
 
+void gecko_profiler_add_timestamp(const mozilla::TimeStamp* aTimeStamp,
+                                  mozilla::TimeStamp* aDestTimeStamp,
+                                  double aMicroseconds) {
+  new (aDestTimeStamp) mozilla::TimeStamp(
+      *aTimeStamp + mozilla::TimeDuration::FromMicroseconds(aMicroseconds));
+}
+
+void gecko_profiler_subtract_timestamp(const mozilla::TimeStamp* aTimeStamp,
+                                       mozilla::TimeStamp* aDestTimeStamp,
+                                       double aMicroseconds) {
+  new (aDestTimeStamp) mozilla::TimeStamp(
+      *aTimeStamp - mozilla::TimeDuration::FromMicroseconds(aMicroseconds));
+}
+
 void gecko_profiler_construct_marker_timing_instant_at(
     mozilla::MarkerTiming* aMarkerTiming, const mozilla::TimeStamp* aTime) {
 #ifdef MOZ_GECKO_PROFILER

tools/profiler/public/ProfilerBindings.h

@@ -43,10 +43,20 @@ void gecko_profiler_construct_label(mozilla::AutoProfilerLabel* aAutoLabel,
                                     JS::ProfilingCategoryPair aCategoryPair);
 void gecko_profiler_destruct_label(mozilla::AutoProfilerLabel* aAutoLabel);
 
-// Construct and destruct the timestamp for profiler time.
+// Construct, clone and destruct the timestamp for profiler time.
 void gecko_profiler_construct_timestamp_now(mozilla::TimeStamp* aTimeStamp);
+void gecko_profiler_clone_timestamp(const mozilla::TimeStamp* aSrcTimeStamp,
+                                    mozilla::TimeStamp* aDestTimeStamp);
 void gecko_profiler_destruct_timestamp(mozilla::TimeStamp* aTimeStamp);
 
+// Addition and subtraction for timestamp.
+void gecko_profiler_add_timestamp(const mozilla::TimeStamp* aTimeStamp,
+                                  mozilla::TimeStamp* aDestTimeStamp,
+                                  double aMicroseconds);
+void gecko_profiler_subtract_timestamp(const mozilla::TimeStamp* aTimeStamp,
+                                       mozilla::TimeStamp* aDestTimeStamp,
+                                       double aMicroseconds);
+
 // Various MarkerTiming constructors and a destructor.
 void gecko_profiler_construct_marker_timing_instant_at(
     mozilla::MarkerTiming* aMarkerTiming, const mozilla::TimeStamp* aTime);

tools/profiler/rust-api/src/time.rs

@@ -34,6 +34,32 @@ impl ProfilerTime {
             ProfilerTime(marker_timing.assume_init())
         }
     }
+
+    pub fn add_microseconds(self, microseconds: f64) -> Self {
+        let mut dest = MaybeUninit::<mozilla::TimeStamp>::uninit();
+        unsafe {
+            bindings::gecko_profiler_add_timestamp(&self.0, dest.as_mut_ptr(), microseconds);
+            ProfilerTime(dest.assume_init())
+        }
+    }
+
+    pub fn subtract_microseconds(self, microseconds: f64) -> Self {
+        let mut dest = MaybeUninit::<mozilla::TimeStamp>::uninit();
+        unsafe {
+            bindings::gecko_profiler_subtract_timestamp(&self.0, dest.as_mut_ptr(), microseconds);
+            ProfilerTime(dest.assume_init())
+        }
+    }
+}
+
+impl Clone for ProfilerTime {
+    fn clone(&self) -> Self {
+        let mut dest = MaybeUninit::<mozilla::TimeStamp>::uninit();
+        unsafe {
+            bindings::gecko_profiler_clone_timestamp(&self.0, dest.as_mut_ptr());
+            ProfilerTime(dest.assume_init())
+        }
+    }
 }
 
 impl Drop for ProfilerTime {