third_party/WebKit/Source/core/paint/PaintTiming.h

// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef PaintTiming_h
#define PaintTiming_h

#include "core/dom/Document.h"
#include "core/paint/FirstMeaningfulPaintDetector.h"
#include "platform/Supplementable.h"
#include "platform/heap/Handle.h"
#include "wtf/Noncopyable.h"

namespace blink {

class LocalFrame;

// PaintTiming is responsible for tracking paint-related timings for a given
// document.
class CORE_EXPORT PaintTiming final
    : public GarbageCollectedFinalized<PaintTiming>,
      public Supplement<Document> {
  WTF_MAKE_NONCOPYABLE(PaintTiming);
  USING_GARBAGE_COLLECTED_MIXIN(PaintTiming);

 public:
  virtual ~PaintTiming() {}

  static PaintTiming& from(Document&);

  // mark*() methods record the time for the given paint event, record a trace
  // event, and notify that paint timing has changed. These methods do nothing
  // (early return) if a time has already been recorded for the given paint
  // event.
  void markFirstPaint();

  // markFirstTextPaint, markFirstImagePaint, and markFirstContentfulPaint
  // will also record first paint if first paint hasn't been recorded yet.
  void markFirstContentfulPaint();

  // markFirstTextPaint and markFirstImagePaint will also record first
  // contentful paint if first contentful paint hasn't been recorded yet.
  void markFirstTextPaint();
  void markFirstImagePaint();

  void setFirstMeaningfulPaint(double stamp);
  void notifyPaint(bool isFirstPaint, bool textPainted, bool imagePainted);

  // The getters below return monotonically-increasing seconds, or zero if the
  // given paint event has not yet occurred. See the comments for
  // monotonicallyIncreasingTime in wtf/CurrentTime.h for additional details.

  // firstPaint returns the first time that anything was painted for the
  // current document.
  double firstPaint() const { return m_firstPaint; }

  // firstContentfulPaint returns the first time that 'contentful' content was
  // painted. For instance, the first time that text or image content was
  // painted.
  double firstContentfulPaint() const { return m_firstContentfulPaint; }

  // firstTextPaint returns the first time that text content was painted.
  double firstTextPaint() const { return m_firstTextPaint; }

  // firstImagePaint returns the first time that image content was painted.
  double firstImagePaint() const { return m_firstImagePaint; }

  // firstMeaningfulPaint returns the first time that page's primary content
  // was painted.
  double firstMeaningfulPaint() const { return m_firstMeaningfulPaint; }

  Document* document() { return m_document.get(); }
  FirstMeaningfulPaintDetector& firstMeaningfulPaintDetector() {
    return *m_fmpDetector;
  }

  DECLARE_VIRTUAL_TRACE();

 private:
  explicit PaintTiming(Document&);
  LocalFrame* frame() const;
  void notifyPaintTimingChanged();

  // set*() set the timing for the given paint event to the given timestamp
  // and record a trace event if the value is currently zero, but do not
  // notify that paint timing changed. These methods can be invoked from other
  // mark*() or set*() methods to make sure that first paint is marked as part
  // of marking first contentful paint, or that first contentful paint is
  // marked as part of marking first text/image paint, for example.
  void setFirstPaint(double stamp);

  // setFirstContentfulPaint will also set first paint time if first paint
  // time has not yet been recorded.
  void setFirstContentfulPaint(double stamp);

  double m_firstPaint = 0.0;
  double m_firstTextPaint = 0.0;
  double m_firstImagePaint = 0.0;
  double m_firstContentfulPaint = 0.0;
  double m_firstMeaningfulPaint = 0.0;

  Member<Document> m_document;
  Member<FirstMeaningfulPaintDetector> m_fmpDetector;
};

}  // namespace blink

#endif