Merge pull request #762 from NativeScript/high-res-time

Add high resolution, low overhead __time

Author: PanayotCankov

runtime/src/main/jni/CallbackHandlers.cpp

@@ -13,6 +13,7 @@
 #include <sstream>
 #include <fstream>
 #include <cstdio>
+#include <chrono>
 #include "MethodCache.h"
 #include "SimpleProfiler.h"
 #include "Runtime.h"
@@ -631,6 +632,12 @@ void CallbackHandlers::LogMethodCallback(const v8::FunctionCallbackInfo<v8::Valu
     }
 }
 
+void CallbackHandlers::TimeCallback(const v8::FunctionCallbackInfo<v8::Value>& args) {
+    auto nano = std::chrono::time_point_cast<std::chrono::nanoseconds>(std::chrono::steady_clock::now());
+    double duration = nano.time_since_epoch().count() / 1000000.0;
+    args.GetReturnValue().Set(duration);
+}
+
 void CallbackHandlers::DumpReferenceTablesMethodCallback(
     const v8::FunctionCallbackInfo<v8::Value>& args) {
     DumpReferenceTablesMethod();

runtime/src/main/jni/CallbackHandlers.h

@@ -56,6 +56,8 @@ class CallbackHandlers {
 
         static void LogMethodCallback(const v8::FunctionCallbackInfo<v8::Value>& args);
 
+        static void TimeCallback(const v8::FunctionCallbackInfo<v8::Value>& args);
+
         static void DumpReferenceTablesMethodCallback(const v8::FunctionCallbackInfo<v8::Value>& args);
 
         static void DumpReferenceTablesMethod();

runtime/src/main/jni/Runtime.cpp

@@ -504,6 +504,7 @@ Isolate* Runtime::PrepareV8Runtime(const string& filesPath, const string& native
     globalTemplate->Set(ArgConverter::ConvertToV8String(isolate, "__disableVerboseLogging"), FunctionTemplate::New(isolate, CallbackHandlers::DisableVerboseLoggingMethodCallback));
     globalTemplate->Set(ArgConverter::ConvertToV8String(isolate, "__exit"), FunctionTemplate::New(isolate, CallbackHandlers::ExitMethodCallback));
     globalTemplate->Set(ArgConverter::ConvertToV8String(isolate, "__runtimeVersion"), ArgConverter::ConvertToV8String(isolate, NATIVE_SCRIPT_RUNTIME_VERSION), readOnlyFlags);
+    globalTemplate->Set(ArgConverter::ConvertToV8String(isolate, "__time"), FunctionTemplate::New(isolate, CallbackHandlers::TimeCallback));
 
     /*
      * Attach `Worker` object constructor only to the main thread (isolate)'s global object

test-app/app/src/main/assets/app/mainpage.js

@@ -45,3 +45,4 @@ require("./tests/field-access-test");
 require("./tests/byte-buffer-test");
 require("./tests/dex-interface-implementation");
 require("./tests/testInterfaceImplementation");
+require("./tests/testRuntimeImplementedAPIs");

test-app/app/src/main/assets/app/tests/testRuntimeImplementedAPIs.js

@@ -0,0 +1,18 @@
+describe("Runtime exposes", function () {
+  it("__time a low overhead, high resolution, time in ms.", function() {
+    var dateTimeStart = Date.now();
+    var timeStart = __time();
+    var acc = 0;
+    var s = android.os.SystemClock.elapsedRealtime();
+    for (var i = 0; i < 1000; i++) {
+      var c = android.os.SystemClock.elapsedRealtime();
+      acc += (c - s);
+      s = c;
+    }
+    var dateTimeEnd = Date.now();
+    var timeEnd = __time();
+    var dateDelta = dateTimeEnd - dateTimeStart;
+    var timeDelta = timeEnd - timeStart;
+    expect(Math.abs(dateDelta - timeDelta) < dateDelta * 0.25).toBe(true);
+  });
+});