moebius#158: The Performance Resource Timing (added support for "workerStart")

https://github.com/MoonchildProductions/moebius/pull/158

dom/performance/PerformanceResourceTiming.cpp

@@ -42,8 +42,22 @@ PerformanceResourceTiming::~PerformanceResourceTiming()
 DOMHighResTimeStamp
 PerformanceResourceTiming::StartTime() const
 {
-  DOMHighResTimeStamp startTime = mTiming->RedirectStartHighRes();
-  return startTime ? startTime : mTiming->FetchStartHighRes();
+  // Force the start time to be the earliest of:
+  //  - RedirectStart
+  //  - WorkerStart
+  //  - AsyncOpen
+  // Ignore zero values.  The RedirectStart and WorkerStart values
+  // can come from earlier redirected channels prior to the AsyncOpen
+  // time being recorded.
+  DOMHighResTimeStamp redirect = mTiming->RedirectStartHighRes();
+  redirect = redirect ? redirect : DBL_MAX;
+
+  DOMHighResTimeStamp worker = mTiming->WorkerStartHighRes();
+  worker = worker ? worker : DBL_MAX;
+
+  DOMHighResTimeStamp asyncOpen = mTiming->AsyncOpenHighRes();
+
+  return std::min(asyncOpen, std::min(redirect, worker));
 }
 
 JSObject*

dom/performance/PerformanceResourceTiming.h

@@ -62,6 +62,12 @@ public:
     mNextHopProtocol = aNextHopProtocol;
   }
 
+  DOMHighResTimeStamp WorkerStart() const {
+    return mTiming && mTiming->TimingAllowed()
+        ? mTiming->WorkerStartHighRes()
+        : 0;
+  }
+
   DOMHighResTimeStamp FetchStart() const {
     return mTiming
         ? mTiming->FetchStartHighRes()

dom/performance/PerformanceTiming.cpp

@@ -73,6 +73,7 @@ PerformanceTiming::InitializeTimingInfo(nsITimedChannel* aChannel)
 {
   if (aChannel) {
     aChannel->GetAsyncOpen(&mAsyncOpen);
+    aChannel->GetDispatchFetchEventStart(&mWorkerStart);
     aChannel->GetAllRedirectsSameOrigin(&mAllRedirectsSameOrigin);
     aChannel->GetRedirectCount(&mRedirectCount);
     aChannel->GetRedirectStart(&mRedirectStart);
@@ -88,31 +89,39 @@ PerformanceTiming::InitializeTimingInfo(nsITimedChannel* aChannel)
     aChannel->GetResponseEnd(&mResponseEnd);
     aChannel->GetCacheReadEnd(&mCacheReadEnd);
 
-    // the performance timing api essentially requires that the event timestamps
-    // are >= asyncOpen().. but in truth the browser engages in a number of
-    // speculative activities that sometimes mean connections and lookups begin
-    // earlier. Workaround that here by just using asyncOpen as the minimum
-    // timestamp for dns and connection info.
+    // The performance timing api essentially requires that the event timestamps
+    // have a strict relation with each other. The truth, however, is the browser
+    // engages in a number of speculative activities that sometimes mean connections
+    // and lookups begin at different times. Workaround that here by clamping
+    // these values to what we expect FetchStart to be.  This means the later of
+    // AsyncOpen or WorkerStart times.
     if (!mAsyncOpen.IsNull()) {
-      if (!mDomainLookupStart.IsNull() && mDomainLookupStart < mAsyncOpen) {
-        mDomainLookupStart = mAsyncOpen;
+      // We want to clamp to the expected FetchStart value.  This is later of
+      // the AsyncOpen and WorkerStart values.
+      const TimeStamp* clampTime = &mAsyncOpen;
+      if (!mWorkerStart.IsNull() && mWorkerStart > mAsyncOpen) {
+        clampTime = &mWorkerStart;
       }
 
-      if (!mDomainLookupEnd.IsNull() && mDomainLookupEnd < mAsyncOpen) {
-        mDomainLookupEnd = mAsyncOpen;
+      if (!mDomainLookupStart.IsNull() && mDomainLookupStart < *clampTime) {
+        mDomainLookupStart = *clampTime;
       }
 
-      if (!mConnectStart.IsNull() && mConnectStart < mAsyncOpen) {
-        mConnectStart = mAsyncOpen;
+      if (!mDomainLookupEnd.IsNull() && mDomainLookupEnd < *clampTime) {
+        mDomainLookupEnd = *clampTime;
+      }
+
+      if (!mConnectStart.IsNull() && mConnectStart < *clampTime) {
+        mConnectStart = *clampTime;
       }
 
       if (mSecureConnection && !mSecureConnectionStart.IsNull() &&
-          mSecureConnectionStart < mAsyncOpen) {
-        mSecureConnectionStart = mAsyncOpen;
+          mSecureConnectionStart < *clampTime) {
+        mSecureConnectionStart = *clampTime;
       }
 
-      if (!mConnectEnd.IsNull() && mConnectEnd < mAsyncOpen) {
-        mConnectEnd = mAsyncOpen;
+      if (!mConnectEnd.IsNull() && mConnectEnd < *clampTime) {
+        mConnectEnd = *clampTime;
       }
     }
   }
@@ -131,9 +140,13 @@ PerformanceTiming::FetchStartHighRes()
     }
     MOZ_ASSERT(!mAsyncOpen.IsNull(), "The fetch start time stamp should always be "
         "valid if the performance timing is enabled");
-    mFetchStart = (!mAsyncOpen.IsNull())
-        ? TimeStampToDOMHighRes(mAsyncOpen)
-        : 0.0;
+    if (!mAsyncOpen.IsNull()) {
+      if (!mWorkerStart.IsNull() && mWorkerStart > mAsyncOpen) {
+        mFetchStart = TimeStampToDOMHighRes(mWorkerStart);
+      } else {
+        mFetchStart = TimeStampToDOMHighRes(mAsyncOpen);
+      }
+    }
   }
   return TimerClamping::ReduceMsTimeValue(mFetchStart);
 }
@@ -180,7 +193,7 @@ PerformanceTiming::TimingAllowed() const
   return mTimingAllowed;
 }
 
-uint16_t
+uint8_t
 PerformanceTiming::GetRedirectCount() const
 {
   if (!nsContentUtils::IsPerformanceTimingEnabled() || !IsInitialized()) {
@@ -205,6 +218,26 @@ PerformanceTiming::ShouldReportCrossOriginRedirect() const
   return (mRedirectCount != 0) && mReportCrossOriginRedirect;
 }
 
+DOMHighResTimeStamp
+PerformanceTiming::AsyncOpenHighRes()
+{
+  if (!nsContentUtils::IsPerformanceTimingEnabled() || !IsInitialized() ||
+      mAsyncOpen.IsNull()) {
+    return mZeroTime;
+  }
+  return TimeStampToReducedDOMHighResOrFetchStart(mAsyncOpen);
+}
+
+DOMHighResTimeStamp
+PerformanceTiming::WorkerStartHighRes()
+{
+  if (!nsContentUtils::IsPerformanceTimingEnabled() || !IsInitialized() ||
+      mWorkerStart.IsNull()) {
+    return mZeroTime;
+  }
+  return TimeStampToReducedDOMHighResOrFetchStart(mWorkerStart);
+}
+
 /**
  * RedirectStartHighRes() is used by both the navigation timing and the
  * resource timing. Since, navigation timing and resource timing check and

dom/performance/PerformanceTiming.h

@@ -139,7 +139,7 @@ public:
     return TimerClamping::ReduceMsTimeValue(GetDOMTiming()->GetUnloadEventEnd());
   }
 
-  uint16_t GetRedirectCount() const;
+  uint8_t GetRedirectCount() const;
 
   // Checks if the resource is either same origin as the page that started
   // the load, or if the response contains the Timing-Allow-Origin header
@@ -155,7 +155,12 @@ public:
   // the timing-allow-origin check in HttpBaseChannel::TimingAllowCheck
   bool ShouldReportCrossOriginRedirect() const;
 
+  // The last channel's AsyncOpen time.  This may occur before the FetchStart
+  // in some cases.
+  DOMHighResTimeStamp AsyncOpenHighRes();
+
   // High resolution (used by resource timing)
+  DOMHighResTimeStamp WorkerStartHighRes();
   DOMHighResTimeStamp FetchStartHighRes();
   DOMHighResTimeStamp RedirectStartHighRes();
   DOMHighResTimeStamp RedirectEndHighRes();
@@ -253,6 +258,7 @@ private:
   DOMHighResTimeStamp mZeroTime;
 
   TimeStamp mAsyncOpen;
+  TimeStamp mWorkerStart;
   TimeStamp mRedirectStart;
   TimeStamp mRedirectEnd;
   TimeStamp mDomainLookupStart;
@@ -265,7 +271,7 @@ private:
   TimeStamp mCacheReadStart;
   TimeStamp mResponseEnd;
   TimeStamp mCacheReadEnd;
-  uint16_t mRedirectCount;
+  uint8_t mRedirectCount;
   bool mTimingAllowed;
   bool mAllRedirectsSameOrigin;
   bool mInitialized;