Quelle VisualViewport.cpp Sprache: C

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "VisualViewport.h"

#include "mozilla/EventDispatcher.h"
#include "mozilla/PresShell.h"
#include "mozilla/ScrollContainerFrame.h"
#include "mozilla/ToString.h"
#include "nsIDocShell.h"
#include "nsGlobalWindowInner.h"
#include "nsPresContext.h"
#include "nsRefreshDriver.h"
#include "DocumentInlines.h"

static mozilla::LazyLogModule sVvpLog("visualviewport");
#define VVP_LOG(...) MOZ_LOG(sVvpLog, LogLevel::Debug, (__VA_ARGS__))

using namespace mozilla;
using namespace mozilla::dom;

VisualViewport::VisualViewport(nsPIDOMWindowInner* aWindow)
    : DOMEventTargetHelper(aWindow) {}

VisualViewport::~VisualViewport() {
  if (mResizeEvent) {
    mResizeEvent->Revoke();
  }

  if (mScrollEvent) {
    mScrollEvent->Revoke();
  }
}

/* virtual */
JSObject* VisualViewport::WrapObject(JSContext* aCx,
                                     JS::Handle<JSObject*> aGivenProto) {
  return VisualViewport_Binding::Wrap(aCx, this, aGivenProto);
}

/* virtual */
void VisualViewport::GetEventTargetParent(EventChainPreVisitor& aVisitor) {
  EventMessage msg = aVisitor.mEvent->mMessage;

  aVisitor.mCanHandle = true;
  EventTarget* parentTarget = nullptr;
  // Only our special internal events are allowed to escape the
  // Visual Viewport and be dispatched further up the DOM tree.
  if (msg == eMozVisualScroll || msg == eMozVisualResize) {
    if (nsPIDOMWindowInner* win = GetOwnerWindow()) {
      if (Document* doc = win->GetExtantDoc()) {
        parentTarget = doc;
      }
    }
  }
  aVisitor.SetParentTarget(parentTarget, false);
}

CSSSize VisualViewport::VisualViewportSize() const {
  CSSSize size = CSSSize(0, 0);

  // Flush layout, as that may affect the answer below (e.g. scrollbars
  // may have appeared, decreasing the available viewport size).
  RefPtr<const VisualViewport> kungFuDeathGrip(this);
  if (Document* doc = GetDocument()) {
    doc->FlushPendingNotifications(FlushType::Layout);
  }

  // Fetch the pres shell after the layout flush, as it might have destroyed it.
  if (PresShell* presShell = GetPresShell()) {
    if (presShell->IsVisualViewportSizeSet()) {
      DynamicToolbarState state = presShell->GetDynamicToolbarState();
      size = CSSRect::FromAppUnits(
          (state == DynamicToolbarState::InTransition ||
           state == DynamicToolbarState::Collapsed)
              ? presShell->GetVisualViewportSizeUpdatedByDynamicToolbar()
              : presShell->GetVisualViewportSize());
    } else {
      ScrollContainerFrame* sf = presShell->GetRootScrollContainerFrame();
      if (sf) {
        size = CSSRect::FromAppUnits(sf->GetScrollPortRect().Size());
      }
    }
  }
  return size;
}

double VisualViewport::Width() const {
  CSSSize size = VisualViewportSize();
  return size.width;
}

double VisualViewport::Height() const {
  CSSSize size = VisualViewportSize();
  return size.height;
}

double VisualViewport::Scale() const {
  double scale = 1;
  if (PresShell* presShell = GetPresShell()) {
    scale = presShell->GetResolution();
  }
  return scale;
}

CSSPoint VisualViewport::VisualViewportOffset() const {
  CSSPoint offset = CSSPoint(0, 0);

  if (PresShell* presShell = GetPresShell()) {
    offset = CSSPoint::FromAppUnits(presShell->GetVisualViewportOffset());
  }
  return offset;
}

CSSPoint VisualViewport::LayoutViewportOffset() const {
  CSSPoint offset = CSSPoint(0, 0);

  if (PresShell* presShell = GetPresShell()) {
    offset = CSSPoint::FromAppUnits(presShell->GetLayoutViewportOffset());
  }
  return offset;
}

double VisualViewport::PageLeft() const { return VisualViewportOffset().X(); }

double VisualViewport::PageTop() const { return VisualViewportOffset().Y(); }

double VisualViewport::OffsetLeft() const {
  return PageLeft() - LayoutViewportOffset().X();
}

double VisualViewport::OffsetTop() const {
  return PageTop() - LayoutViewportOffset().Y();
}

Document* VisualViewport::GetDocument() const {
  nsCOMPtr<nsPIDOMWindowInner> window = GetOwnerWindow();
  if (!window) {
    return nullptr;
  }

  nsIDocShell* docShell = window->GetDocShell();
  if (!docShell) {
    return nullptr;
  }

  return docShell->GetDocument();
}

PresShell* VisualViewport::GetPresShell() const {
  RefPtr<Document> document = GetDocument();
  return document ? document->GetPresShell() : nullptr;
}

nsPresContext* VisualViewport::GetPresContext() const {
  RefPtr<Document> document = GetDocument();
  return document ? document->GetPresContext() : nullptr;
}

/* ================= Resize event handling ================= */

void VisualViewport::PostResizeEvent() {
  VVP_LOG("%p: PostResizeEvent (pre-existing: %d)\n", this, !!mResizeEvent);
  nsPresContext* presContext = GetPresContext();
  if (mResizeEvent && mResizeEvent->HasPresContext(presContext)) {
    return;
  }
  if (mResizeEvent) {
    // prescontext changed, so discard the old resize event and queue a new one
    mResizeEvent->Revoke();
    mResizeEvent = nullptr;
  }

  // The event constructor will register itself with the refresh driver.
  if (presContext) {
    mResizeEvent = new VisualViewportResizeEvent(this, presContext);
    VVP_LOG("%p: PostResizeEvent, created new event\n", this);
  }
}

VisualViewport::VisualViewportResizeEvent::VisualViewportResizeEvent(
    VisualViewport* aViewport, nsPresContext* aPresContext)
    : Runnable("VisualViewport::VisualViewportResizeEvent"),
      mViewport(aViewport),
      mPresContext(aPresContext) {
  VVP_LOG("%p: Registering PostResize on %p %p\n", aViewport, aPresContext,
          aPresContext->RefreshDriver());
  aPresContext->RefreshDriver()->PostVisualViewportResizeEvent(this);
}

bool VisualViewport::VisualViewportResizeEvent::HasPresContext(
    nsPresContext* aContext) const {
  return mPresContext.get() == aContext;
}

void VisualViewport::VisualViewportResizeEvent::Revoke() {
  mViewport = nullptr;
  mPresContext = nullptr;
}

// TODO: Convert this to MOZ_CAN_RUN_SCRIPT (bug 1415230, bug 1535398)
MOZ_CAN_RUN_SCRIPT_BOUNDARY NS_IMETHODIMP
VisualViewport::VisualViewportResizeEvent::Run() {
  if (RefPtr<VisualViewport> viewport = mViewport) {
    viewport->FireResizeEvent();
  }
  return NS_OK;
}

void VisualViewport::FireResizeEvent() {
  MOZ_ASSERT(mResizeEvent);
  mResizeEvent->Revoke();
  mResizeEvent = nullptr;

  RefPtr<nsPresContext> presContext = GetPresContext();

  VVP_LOG("%p, FireResizeEvent, fire mozvisualresize\n", this);
  WidgetEvent mozEvent(true, eMozVisualResize);
  mozEvent.mFlags.mOnlySystemGroupDispatch = true;
  EventDispatcher::Dispatch(this, presContext, &mozEvent);

  VVP_LOG("%p, FireResizeEvent, fire VisualViewport resize\n", this);
  WidgetEvent event(true, eResize);
  event.mFlags.mBubbles = false;
  event.mFlags.mCancelable = false;
  EventDispatcher::Dispatch(this, presContext, &event);
}

/* ================= Scroll event handling ================= */

void VisualViewport::PostScrollEvent(const nsPoint& aPrevVisualOffset,
                                     const nsPoint& aPrevLayoutOffset) {
  VVP_LOG("%p: PostScrollEvent, prevRelativeOffset=%s (pre-existing: %d)\n",
          this, ToString(aPrevVisualOffset - aPrevLayoutOffset).c_str(),
          !!mScrollEvent);
  nsPresContext* presContext = GetPresContext();
  if (mScrollEvent && mScrollEvent->HasPresContext(presContext)) {
    return;
  }

  if (mScrollEvent) {
    // prescontext changed, so discard the old scroll event and queue a new one
    mScrollEvent->Revoke();
    mScrollEvent = nullptr;
  }

  // The event constructor will register itself with the refresh driver.
  if (presContext) {
    mScrollEvent = new VisualViewportScrollEvent(
        this, presContext, aPrevVisualOffset, aPrevLayoutOffset);
    VVP_LOG("%p: PostScrollEvent, created new event\n", this);
  }
}

VisualViewport::VisualViewportScrollEvent::VisualViewportScrollEvent(
    VisualViewport* aViewport, nsPresContext* aPresContext,
    const nsPoint& aPrevVisualOffset, const nsPoint& aPrevLayoutOffset)
    : Runnable("VisualViewport::VisualViewportScrollEvent"),
      mViewport(aViewport),
      mPresContext(aPresContext),
      mPrevVisualOffset(aPrevVisualOffset),
      mPrevLayoutOffset(aPrevLayoutOffset) {
  VVP_LOG("%p: Registering PostScroll on %p %p\n", aViewport, aPresContext,
          aPresContext->RefreshDriver());
  aPresContext->RefreshDriver()->PostVisualViewportScrollEvent(this);
}

bool VisualViewport::VisualViewportScrollEvent::HasPresContext(
    nsPresContext* aContext) const {
  return mPresContext.get() == aContext;
}

void VisualViewport::VisualViewportScrollEvent::Revoke() {
  mViewport = nullptr;
  mPresContext = nullptr;
}

// TODO: Convert this to MOZ_CAN_RUN_SCRIPT (bug 1415230, bug 1535398)
MOZ_CAN_RUN_SCRIPT_BOUNDARY NS_IMETHODIMP
VisualViewport::VisualViewportScrollEvent::Run() {
  if (RefPtr<VisualViewport> viewport = mViewport) {
    viewport->FireScrollEvent();
  }
  return NS_OK;
}

void VisualViewport::FireScrollEvent() {
  MOZ_ASSERT(mScrollEvent);
  nsPoint prevVisualOffset = mScrollEvent->PrevVisualOffset();
  nsPoint prevLayoutOffset = mScrollEvent->PrevLayoutOffset();
  mScrollEvent->Revoke();
  mScrollEvent = nullptr;

  if (RefPtr<PresShell> presShell = GetPresShell()) {
    RefPtr<nsPresContext> presContext = GetPresContext();

    if (presShell->GetVisualViewportOffset() != prevVisualOffset) {
      // The internal event will be fired whenever the visual viewport's
      // *absolute* offset changed, i.e. relative to the page.
      VVP_LOG("%p: FireScrollEvent, fire mozvisualscroll\n", this);
      WidgetEvent mozEvent(true, eMozVisualScroll);
      mozEvent.mFlags.mOnlySystemGroupDispatch = true;
      EventDispatcher::Dispatch(this, presContext, &mozEvent);
    }

    // Check whether the relative visual viewport offset actually changed -
    // maybe both visual and layout viewport scrolled together and there was no
    // change after all.
    nsPoint curRelativeOffset =
        presShell->GetVisualViewportOffsetRelativeToLayoutViewport();
    nsPoint prevRelativeOffset = prevVisualOffset - prevLayoutOffset;
    VVP_LOG(
        "%p: FireScrollEvent, curRelativeOffset %s, "
        "prevRelativeOffset %s\n",
        this, ToString(curRelativeOffset).c_str(),
        ToString(prevRelativeOffset).c_str());
    if (curRelativeOffset != prevRelativeOffset) {
      VVP_LOG("%p, FireScrollEvent, fire VisualViewport scroll\n", this);
      WidgetGUIEvent event(true, eScroll, nullptr);
      event.mFlags.mBubbles = false;
      event.mFlags.mCancelable = false;
      EventDispatcher::Dispatch(this, presContext, &event);
    }
  }
}

quality100%

¤ Dauer der Verarbeitung: 0.1 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.