1 files changed, 357 insertions, 0 deletions
diff --git a/layout/base/AccessibleCaret.cpp b/layout/base/AccessibleCaret.cpp
new file mode 100644
index 0000000000..d0285a8c95
--- /dev/null
+++ b/layout/base/AccessibleCaret.cpp
@@ -0,0 +1,357 @@
+/* -*- 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 "AccessibleCaret.h"
+
+#include "AccessibleCaretLogger.h"
+#include "mozilla/FloatingPoint.h"
+#include "mozilla/PresShell.h"
+#include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/ToString.h"
+#include "nsCanvasFrame.h"
+#include "nsCaret.h"
+#include "nsCSSFrameConstructor.h"
+#include "nsDOMTokenList.h"
+#include "nsIFrame.h"
+#include "nsLayoutUtils.h"
+#include "nsPlaceholderFrame.h"
+
+namespace mozilla {
+using namespace dom;
+
+#undef AC_LOG
+#define AC_LOG(message, ...) \
+  AC_LOG_BASE("AccessibleCaret (%p): " message, this, ##__VA_ARGS__);
+
+#undef AC_LOGV
+#define AC_LOGV(message, ...) \
+  AC_LOGV_BASE("AccessibleCaret (%p): " message, this, ##__VA_ARGS__);
+
+NS_IMPL_ISUPPORTS(AccessibleCaret::DummyTouchListener, nsIDOMEventListener)
+
+const nsLiteralString AccessibleCaret::sTextOverlayElementId =
+    u"text-overlay"_ns;
+const nsLiteralString AccessibleCaret::sCaretImageElementId = u"image"_ns;
+
+#define AC_PROCESS_ENUM_TO_STREAM(e) \
+  case (e):                          \
+    aStream << #e;                   \
+    break;
+std::ostream& operator<<(std::ostream& aStream,
+                         const AccessibleCaret::Appearance& aAppearance) {
+  using Appearance = AccessibleCaret::Appearance;
+  switch (aAppearance) {
+    AC_PROCESS_ENUM_TO_STREAM(Appearance::None);
+    AC_PROCESS_ENUM_TO_STREAM(Appearance::Normal);
+    AC_PROCESS_ENUM_TO_STREAM(Appearance::NormalNotShown);
+    AC_PROCESS_ENUM_TO_STREAM(Appearance::Left);
+    AC_PROCESS_ENUM_TO_STREAM(Appearance::Right);
+  }
+  return aStream;
+}
+
+std::ostream& operator<<(
+    std::ostream& aStream,
+    const AccessibleCaret::PositionChangedResult& aResult) {
+  using PositionChangedResult = AccessibleCaret::PositionChangedResult;
+  switch (aResult) {
+    AC_PROCESS_ENUM_TO_STREAM(PositionChangedResult::NotChanged);
+    AC_PROCESS_ENUM_TO_STREAM(PositionChangedResult::Position);
+    AC_PROCESS_ENUM_TO_STREAM(PositionChangedResult::Zoom);
+    AC_PROCESS_ENUM_TO_STREAM(PositionChangedResult::Invisible);
+  }
+  return aStream;
+}
+#undef AC_PROCESS_ENUM_TO_STREAM
+
+// -----------------------------------------------------------------------------
+// Implementation of AccessibleCaret methods
+
+AccessibleCaret::AccessibleCaret(PresShell* aPresShell)
+    : mPresShell(aPresShell) {
+  // Check all resources required.
+  if (mPresShell) {
+    MOZ_ASSERT(RootFrame());
+    MOZ_ASSERT(mPresShell->GetDocument());
+    InjectCaretElement(mPresShell->GetDocument());
+  }
+}
+
+AccessibleCaret::~AccessibleCaret() {
+  if (mPresShell) {
+    RemoveCaretElement(mPresShell->GetDocument());
+  }
+}
+
+void AccessibleCaret::SetAppearance(Appearance aAppearance) {
+  if (mAppearance == aAppearance) {
+    return;
+  }
+
+  ErrorResult rv;
+  CaretElement().ClassList()->Remove(AppearanceString(mAppearance), rv);
+  MOZ_ASSERT(!rv.Failed(), "Remove old appearance failed!");
+
+  CaretElement().ClassList()->Add(AppearanceString(aAppearance), rv);
+  MOZ_ASSERT(!rv.Failed(), "Add new appearance failed!");
+
+  AC_LOG("%s: %s -> %s", __FUNCTION__, ToString(mAppearance).c_str(),
+         ToString(aAppearance).c_str());
+
+  mAppearance = aAppearance;
+
+  // Need to reset rect since the cached rect will be compared in SetPosition.
+  if (mAppearance == Appearance::None) {
+    ClearCachedData();
+  }
+}
+
+/* static */
+nsAutoString AccessibleCaret::AppearanceString(Appearance aAppearance) {
+  nsAutoString string;
+  switch (aAppearance) {
+    case Appearance::None:
+      string = u"none"_ns;
+      break;
+    case Appearance::NormalNotShown:
+      string = u"hidden"_ns;
+      break;
+    case Appearance::Normal:
+      string = u"normal"_ns;
+      break;
+    case Appearance::Right:
+      string = u"right"_ns;
+      break;
+    case Appearance::Left:
+      string = u"left"_ns;
+      break;
+  }
+  return string;
+}
+
+bool AccessibleCaret::Intersects(const AccessibleCaret& aCaret) const {
+  MOZ_ASSERT(mPresShell == aCaret.mPresShell);
+
+  if (!IsVisuallyVisible() || !aCaret.IsVisuallyVisible()) {
+    return false;
+  }
+
+  nsRect rect =
+      nsLayoutUtils::GetRectRelativeToFrame(&CaretElement(), RootFrame());
+  nsRect rhsRect = nsLayoutUtils::GetRectRelativeToFrame(&aCaret.CaretElement(),
+                                                         RootFrame());
+  return rect.Intersects(rhsRect);
+}
+
+bool AccessibleCaret::Contains(const nsPoint& aPoint,
+                               TouchArea aTouchArea) const {
+  if (!IsVisuallyVisible()) {
+    return false;
+  }
+
+  nsRect textOverlayRect =
+      nsLayoutUtils::GetRectRelativeToFrame(TextOverlayElement(), RootFrame());
+  nsRect caretImageRect =
+      nsLayoutUtils::GetRectRelativeToFrame(CaretImageElement(), RootFrame());
+
+  if (aTouchArea == TouchArea::CaretImage) {
+    return caretImageRect.Contains(aPoint);
+  }
+
+  MOZ_ASSERT(aTouchArea == TouchArea::Full, "Unexpected TouchArea type!");
+  return textOverlayRect.Contains(aPoint) || caretImageRect.Contains(aPoint);
+}
+
+void AccessibleCaret::EnsureApzAware() {
+  // If the caret element was cloned, the listener might have been lost. So
+  // if that's the case we register a dummy listener if there isn't one on
+  // the element already.
+  if (!CaretElement().IsApzAware()) {
+    // FIXME(emilio): Is this needed anymore?
+    CaretElement().AddEventListener(u"touchstart"_ns, mDummyTouchListener,
+                                    false);
+  }
+}
+
+bool AccessibleCaret::IsInPositionFixedSubtree() const {
+  return nsLayoutUtils::IsInPositionFixedSubtree(
+      mImaginaryCaretReferenceFrame.GetFrame());
+}
+
+void AccessibleCaret::InjectCaretElement(Document* aDocument) {
+  ErrorResult rv;
+  RefPtr<Element> element = CreateCaretElement(aDocument);
+  mCaretElementHolder = aDocument->InsertAnonymousContent(*element, rv);
+
+  MOZ_ASSERT(!rv.Failed(), "Insert anonymous content should not fail!");
+  MOZ_ASSERT(mCaretElementHolder, "We must have anonymous content!");
+
+  // InsertAnonymousContent will clone the element to make an AnonymousContent.
+  // Since event listeners are not being cloned when cloning a node, we need to
+  // add the listener here.
+  EnsureApzAware();
+}
+
+already_AddRefed<Element> AccessibleCaret::CreateCaretElement(
+    Document* aDocument) const {
+  // Content structure of AccessibleCaret
+  // <div class="moz-accessiblecaret">  <- CaretElement()
+  //   <div id="text-overlay">          <- TextOverlayElement()
+  //   <div id="image">                 <- CaretImageElement()
+
+  ErrorResult rv;
+  RefPtr<Element> parent = aDocument->CreateHTMLElement(nsGkAtoms::div);
+  parent->ClassList()->Add(u"moz-accessiblecaret"_ns, rv);
+  parent->ClassList()->Add(u"none"_ns, rv);
+
+  auto CreateAndAppendChildElement =
+      [aDocument, &parent](const nsLiteralString& aElementId) {
+        RefPtr<Element> child = aDocument->CreateHTMLElement(nsGkAtoms::div);
+        child->SetAttr(kNameSpaceID_None, nsGkAtoms::id, aElementId, true);
+        parent->AppendChildTo(child, false);
+      };
+
+  CreateAndAppendChildElement(sTextOverlayElementId);
+  CreateAndAppendChildElement(sCaretImageElementId);
+
+  return parent.forget();
+}
+
+void AccessibleCaret::RemoveCaretElement(Document* aDocument) {
+  CaretElement().RemoveEventListener(u"touchstart"_ns, mDummyTouchListener,
+                                     false);
+
+  aDocument->RemoveAnonymousContent(*mCaretElementHolder, IgnoreErrors());
+}
+
+void AccessibleCaret::ClearCachedData() {
+  mImaginaryCaretRect = nsRect();
+  mImaginaryCaretRectInContainerFrame = nsRect();
+  mImaginaryCaretReferenceFrame = nullptr;
+  mZoomLevel = 0.0f;
+}
+
+AccessibleCaret::PositionChangedResult AccessibleCaret::SetPosition(
+    nsIFrame* aFrame, int32_t aOffset) {
+  if (!CustomContentContainerFrame()) {
+    return PositionChangedResult::NotChanged;
+  }
+
+  nsRect imaginaryCaretRectInFrame =
+      nsCaret::GetGeometryForFrame(aFrame, aOffset, nullptr);
+
+  imaginaryCaretRectInFrame =
+      nsLayoutUtils::ClampRectToScrollFrames(aFrame, imaginaryCaretRectInFrame);
+
+  if (imaginaryCaretRectInFrame.IsEmpty()) {
+    // Don't bother to set the caret position since it's invisible.
+    ClearCachedData();
+    return PositionChangedResult::Invisible;
+  }
+
+  // SetCaretElementStyle() requires the input rect relative to the custom
+  // content container frame.
+  nsRect imaginaryCaretRectInContainerFrame = imaginaryCaretRectInFrame;
+  nsLayoutUtils::TransformRect(aFrame, CustomContentContainerFrame(),
+                               imaginaryCaretRectInContainerFrame);
+  const float zoomLevel = GetZoomLevel();
+  const bool isSamePosition = imaginaryCaretRectInContainerFrame.IsEqualEdges(
+      mImaginaryCaretRectInContainerFrame);
+  const bool isSameZoomLevel = FuzzyEqualsMultiplicative(zoomLevel, mZoomLevel);
+
+  // Always update cached mImaginaryCaretRect (relative to the root frame)
+  // because it can change when the caret is scrolled.
+  mImaginaryCaretRect = imaginaryCaretRectInFrame;
+  nsLayoutUtils::TransformRect(aFrame, RootFrame(), mImaginaryCaretRect);
+
+  if (isSamePosition && isSameZoomLevel) {
+    return PositionChangedResult::NotChanged;
+  }
+
+  mImaginaryCaretRectInContainerFrame = imaginaryCaretRectInContainerFrame;
+  mImaginaryCaretReferenceFrame = aFrame;
+  mZoomLevel = zoomLevel;
+
+  SetCaretElementStyle(imaginaryCaretRectInContainerFrame, mZoomLevel);
+
+  return isSamePosition ? PositionChangedResult::Zoom
+                        : PositionChangedResult::Position;
+}
+
+nsIFrame* AccessibleCaret::RootFrame() const {
+  return mPresShell->GetRootFrame();
+}
+
+nsIFrame* AccessibleCaret::CustomContentContainerFrame() const {
+  nsCanvasFrame* canvasFrame = mPresShell->GetCanvasFrame();
+  Element* container = canvasFrame->GetCustomContentContainer();
+  nsIFrame* containerFrame = container->GetPrimaryFrame();
+  return containerFrame;
+}
+
+void AccessibleCaret::SetCaretElementStyle(const nsRect& aRect,
+                                           float aZoomLevel) {
+  nsPoint position = CaretElementPosition(aRect);
+  nsAutoString styleStr;
+  // We can't use AppendPrintf here, because it does locale-specific
+  // formatting of floating-point values.
+  styleStr.AppendLiteral("left: ");
+  styleStr.AppendFloat(nsPresContext::AppUnitsToFloatCSSPixels(position.x));
+  styleStr.AppendLiteral("px; top: ");
+  styleStr.AppendFloat(nsPresContext::AppUnitsToFloatCSSPixels(position.y));
+  styleStr.AppendLiteral("px; width: ");
+  styleStr.AppendFloat(StaticPrefs::layout_accessiblecaret_width() /
+                       aZoomLevel);
+  styleStr.AppendLiteral("px; margin-left: ");
+  styleStr.AppendFloat(StaticPrefs::layout_accessiblecaret_margin_left() /
+                       aZoomLevel);
+  styleStr.AppendLiteral("px; transition-duration: ");
+  styleStr.AppendFloat(
+      StaticPrefs::layout_accessiblecaret_transition_duration());
+  styleStr.AppendLiteral("ms");
+
+  CaretElement().SetAttr(kNameSpaceID_None, nsGkAtoms::style, styleStr, true);
+  AC_LOG("%s: %s", __FUNCTION__, NS_ConvertUTF16toUTF8(styleStr).get());
+
+  // Set style string for children.
+  SetTextOverlayElementStyle(aRect, aZoomLevel);
+  SetCaretImageElementStyle(aRect, aZoomLevel);
+}
+
+void AccessibleCaret::SetTextOverlayElementStyle(const nsRect& aRect,
+                                                 float aZoomLevel) {
+  nsAutoString styleStr;
+  styleStr.AppendLiteral("height: ");
+  styleStr.AppendFloat(nsPresContext::AppUnitsToFloatCSSPixels(aRect.height));
+  styleStr.AppendLiteral("px;");
+  TextOverlayElement()->SetAttr(kNameSpaceID_None, nsGkAtoms::style, styleStr,
+                                true);
+  AC_LOG("%s: %s", __FUNCTION__, NS_ConvertUTF16toUTF8(styleStr).get());
+}
+
+void AccessibleCaret::SetCaretImageElementStyle(const nsRect& aRect,
+                                                float aZoomLevel) {
+  nsAutoString styleStr;
+  styleStr.AppendLiteral("height: ");
+  styleStr.AppendFloat(StaticPrefs::layout_accessiblecaret_height() /
+                       aZoomLevel);
+  styleStr.AppendLiteral("px;");
+  CaretImageElement()->SetAttr(kNameSpaceID_None, nsGkAtoms::style, styleStr,
+                               true);
+  AC_LOG("%s: %s", __FUNCTION__, NS_ConvertUTF16toUTF8(styleStr).get());
+}
+
+float AccessibleCaret::GetZoomLevel() {
+  // Full zoom on desktop.
+  float fullZoom = mPresShell->GetPresContext()->GetFullZoom();
+
+  // Pinch-zoom on fennec.
+  float resolution = mPresShell->GetCumulativeResolution();
+
+  return fullZoom * resolution;
+}
+
+}  // namespace mozilla