1 files changed, 327 insertions, 0 deletions
diff --git a/dom/base/VisualViewport.cpp b/dom/base/VisualViewport.cpp
new file mode 100644
index 0000000000..2e466ce041
--- /dev/null
+++ b/dom/base/VisualViewport.cpp
@@ -0,0 +1,327 @@
+/* -*- 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/ToString.h"
+#include "nsIScrollableFrame.h"
+#include "nsIDocShell.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 = GetOwner()) {
+      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 {
+      nsIScrollableFrame* sf = presShell->GetRootScrollFrameAsScrollable();
+      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 = GetOwner();
+  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);
+    }
+  }
+}