dom/base/ScrollingMetrics.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "ScrollingMetrics.h"
   8 #include "mozilla/dom/ContentParent.h"
   9 #include "mozilla/StaticPrefs_browser.h"
  10
  11 namespace mozilla {
  12
  13 static TimeStamp gScrollingStartTime;
  14 static TimeStamp gScrollingEndTime;
  15 static uint32_t gScrollDistanceCSSPixels = 0;
  16 static dom::InteractionData gScrollingInteraction = {};
  17
  18 void ScrollingMetrics::OnScrollingInteractionEnded() {
  19   // We are only interested in content process scrolling
  20   if (XRE_IsParentProcess()) {
  21     return;
  22   }
  23
  24   if (!gScrollingStartTime.IsNull() && !gScrollingEndTime.IsNull()) {
  25     gScrollingInteraction.mInteractionCount++;
  26     gScrollingInteraction.mInteractionTimeInMilliseconds +=
  27         static_cast<uint32_t>(
  28             (gScrollingEndTime - gScrollingStartTime).ToMilliseconds());
  29
  30     gScrollingInteraction.mScrollingDistanceInPixels +=
  31         gScrollDistanceCSSPixels;
  32   }
  33
  34   gScrollDistanceCSSPixels = 0;
  35   gScrollingStartTime = TimeStamp();
  36   gScrollingEndTime = TimeStamp();
  37 }
  38
  39 void ScrollingMetrics::OnScrollingInteraction(CSSCoord distanceScrolled) {
  40   // We are only interested in content process scrolling
  41   if (XRE_IsParentProcess()) {
  42     return;
  43   }
  44
  45   TimeStamp now = TimeStamp::Now();
  46   if (gScrollingEndTime.IsNull()) {
  47     gScrollingEndTime = now;
  48   }
  49
  50   TimeDuration delay = now - gScrollingEndTime;
  51
  52   // Has it been too long since the last scroll input event to consider it part
  53   // of the same interaction?
  54   if (delay >
  55       TimeDuration::FromMilliseconds(
  56           StaticPrefs::browser_places_interactions_scrolling_timeout_ms())) {
  57     OnScrollingInteractionEnded();
  58   }
  59
  60   if (gScrollingStartTime.IsNull()) {
  61     gScrollingStartTime = now;
  62   }
  63   gScrollingEndTime = now;
  64   gScrollDistanceCSSPixels += static_cast<uint32_t>(distanceScrolled);
  65 }
  66
  67 StaticAutoPtr<ScrollingMetrics> ScrollingMetrics::sSingleton;
  68
  69 ScrollingMetrics* ScrollingMetrics::GetSingleton() {
  70   if (!sSingleton) {
  71     sSingleton = new ScrollingMetrics;
  72   }
  73
  74   return sSingleton.get();
  75 }
  76
  77 struct ScrollingMetricsCollector {
  78   void AppendScrollingMetrics(const std::tuple<uint32_t, uint32_t>& aMetrics,
  79                               dom::ContentParent* aParent) {
  80     mTimeScrolledMS += std::get<0>(aMetrics);
  81     mDistanceScrolledPixels += std::get<1>(aMetrics);
  82   }
  83
  84   ~ScrollingMetricsCollector() {
  85     mPromiseHolder.Resolve(
  86         std::make_tuple(mTimeScrolledMS, mDistanceScrolledPixels), __func__);
  87   }
  88
  89   uint32_t mTimeScrolledMS = 0;
  90   uint32_t mDistanceScrolledPixels = 0;
  91   MozPromiseHolder<ScrollingMetrics::ScrollingMetricsPromise> mPromiseHolder;
  92 };
  93
  94 auto ScrollingMetrics::CollectScrollingMetricsInternal()
  95     -> RefPtr<ScrollingMetrics::ScrollingMetricsPromise> {
  96   std::shared_ptr<ScrollingMetricsCollector> collector =
  97       std::make_shared<ScrollingMetricsCollector>();
  98
  99   nsTArray<dom::ContentParent*> contentParents;
 100   dom::ContentParent::GetAll(contentParents);
 101   for (dom::ContentParent* parent : contentParents) {
 102     RefPtr<dom::ContentParent> parentRef = parent;
 103     parent->SendCollectScrollingMetrics(
 104         [collector, parentRef](const std::tuple<uint32_t, uint32_t>& aMetrics) {
 105           collector->AppendScrollingMetrics(aMetrics, parentRef.get());
 106         },
 107         [](mozilla::ipc::ResponseRejectReason) {});
 108   }
 109
 110   return collector->mPromiseHolder.Ensure(__func__);
 111 }
 112
 113 std::tuple<uint32_t, uint32_t>
 114 ScrollingMetrics::CollectLocalScrollingMetricsInternal() {
 115   OnScrollingInteractionEnded();
 116
 117   std::tuple<uint32_t, uint32_t> metrics =
 118       std::make_tuple(gScrollingInteraction.mInteractionTimeInMilliseconds,
 119                       gScrollingInteraction.mScrollingDistanceInPixels);
 120   gScrollingInteraction = {};
 121   return metrics;
 122 }
 123
 124 }  // namespace mozilla