1 files changed, 376 insertions, 0 deletions
diff --git a/accessible/base/TextRange.cpp b/accessible/base/TextRange.cpp
new file mode 100644
index 0000000000..15ff8bd05a
--- /dev/null
+++ b/accessible/base/TextRange.cpp
@@ -0,0 +1,376 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=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 "TextRange-inl.h"
+
+#include "LocalAccessible-inl.h"
+#include "HyperTextAccessible-inl.h"
+#include "mozilla/IntegerRange.h"
+#include "mozilla/dom/Selection.h"
+#include "nsAccUtils.h"
+
+namespace mozilla {
+namespace a11y {
+
+/**
+ * Returns a text point for aAcc within aContainer.
+ */
+static void ToTextPoint(Accessible* aAcc, Accessible** aContainer,
+                        int32_t* aOffset, bool aIsBefore = true) {
+  if (aAcc->IsHyperText()) {
+    *aContainer = aAcc;
+    *aOffset =
+        aIsBefore
+            ? 0
+            : static_cast<int32_t>(aAcc->AsHyperTextBase()->CharacterCount());
+    return;
+  }
+
+  Accessible* child = nullptr;
+  Accessible* parent = aAcc;
+  do {
+    child = parent;
+    parent = parent->Parent();
+  } while (parent && !parent->IsHyperText());
+
+  if (parent) {
+    *aContainer = parent;
+    *aOffset = parent->AsHyperTextBase()->GetChildOffset(
+        child->IndexInParent() + static_cast<int32_t>(!aIsBefore));
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// TextPoint
+
+bool TextPoint::operator<(const TextPoint& aPoint) const {
+  if (mContainer == aPoint.mContainer) return mOffset < aPoint.mOffset;
+
+  // Build the chain of parents
+  Accessible* p1 = mContainer;
+  Accessible* p2 = aPoint.mContainer;
+  AutoTArray<Accessible*, 30> parents1, parents2;
+  do {
+    parents1.AppendElement(p1);
+    p1 = p1->Parent();
+  } while (p1);
+  do {
+    parents2.AppendElement(p2);
+    p2 = p2->Parent();
+  } while (p2);
+
+  // Find where the parent chain differs
+  uint32_t pos1 = parents1.Length(), pos2 = parents2.Length();
+  for (uint32_t len = std::min(pos1, pos2); len > 0; --len) {
+    Accessible* child1 = parents1.ElementAt(--pos1);
+    Accessible* child2 = parents2.ElementAt(--pos2);
+    if (child1 != child2) {
+      return child1->IndexInParent() < child2->IndexInParent();
+    }
+  }
+
+  if (pos1 != 0) {
+    // If parents1 is a superset of parents2 then mContainer is a
+    // descendant of aPoint.mContainer. The next element down in parents1
+    // is mContainer's ancestor that is the child of aPoint.mContainer.
+    // We compare its end offset in aPoint.mContainer with aPoint.mOffset.
+    Accessible* child = parents1.ElementAt(pos1 - 1);
+    MOZ_ASSERT(child->Parent() == aPoint.mContainer);
+    return child->EndOffset() < static_cast<uint32_t>(aPoint.mOffset);
+  }
+
+  if (pos2 != 0) {
+    // If parents2 is a superset of parents1 then aPoint.mContainer is a
+    // descendant of mContainer. The next element down in parents2
+    // is aPoint.mContainer's ancestor that is the child of mContainer.
+    // We compare its start offset in mContainer with mOffset.
+    Accessible* child = parents2.ElementAt(pos2 - 1);
+    MOZ_ASSERT(child->Parent() == mContainer);
+    return static_cast<uint32_t>(mOffset) < child->StartOffset();
+  }
+
+  NS_ERROR("Broken tree?!");
+  return false;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// TextRange
+
+TextRange::TextRange(Accessible* aRoot, Accessible* aStartContainer,
+                     int32_t aStartOffset, Accessible* aEndContainer,
+                     int32_t aEndOffset)
+    : mRoot(aRoot),
+      mStartContainer(aStartContainer),
+      mEndContainer(aEndContainer),
+      mStartOffset(aStartOffset),
+      mEndOffset(aEndOffset) {}
+
+bool TextRange::Crop(Accessible* aContainer) {
+  uint32_t boundaryPos = 0, containerPos = 0;
+  AutoTArray<Accessible*, 30> boundaryParents, containerParents;
+
+  // Crop the start boundary.
+  Accessible* container = nullptr;
+  HyperTextAccessibleBase* startHyper = mStartContainer->AsHyperTextBase();
+  Accessible* boundary = startHyper->GetChildAtOffset(mStartOffset);
+  if (boundary != aContainer) {
+    CommonParent(boundary, aContainer, &boundaryParents, &boundaryPos,
+                 &containerParents, &containerPos);
+
+    if (boundaryPos == 0) {
+      if (containerPos != 0) {
+        // The container is contained by the start boundary, reduce the range to
+        // the point starting at the container.
+        ToTextPoint(aContainer, &mStartContainer, &mStartOffset);
+      } else {
+        // The start boundary and the container are siblings.
+        container = aContainer;
+      }
+    } else {
+      // The container does not contain the start boundary.
+      boundary = boundaryParents[boundaryPos];
+      container = containerParents[containerPos];
+    }
+
+    if (container) {
+      // If the range start is after the container, then make the range invalid.
+      if (boundary->IndexInParent() > container->IndexInParent()) {
+        return !!(mRoot = nullptr);
+      }
+
+      // If the range starts before the container, then reduce the range to
+      // the point starting at the container.
+      if (boundary->IndexInParent() < container->IndexInParent()) {
+        ToTextPoint(container, &mStartContainer, &mStartOffset);
+      }
+    }
+
+    boundaryParents.SetLengthAndRetainStorage(0);
+    containerParents.SetLengthAndRetainStorage(0);
+  }
+
+  HyperTextAccessibleBase* endHyper = mEndContainer->AsHyperTextBase();
+  boundary = endHyper->GetChildAtOffset(mEndOffset);
+  if (boundary == aContainer) {
+    return true;
+  }
+
+  // Crop the end boundary.
+  container = nullptr;
+  CommonParent(boundary, aContainer, &boundaryParents, &boundaryPos,
+               &containerParents, &containerPos);
+
+  if (boundaryPos == 0) {
+    if (containerPos != 0) {
+      ToTextPoint(aContainer, &mEndContainer, &mEndOffset, false);
+    } else {
+      container = aContainer;
+    }
+  } else {
+    boundary = boundaryParents[boundaryPos];
+    container = containerParents[containerPos];
+  }
+
+  if (!container) {
+    return true;
+  }
+
+  if (boundary->IndexInParent() < container->IndexInParent()) {
+    return !!(mRoot = nullptr);
+  }
+
+  if (boundary->IndexInParent() > container->IndexInParent()) {
+    ToTextPoint(container, &mEndContainer, &mEndOffset, false);
+  }
+
+  return true;
+}
+
+/**
+ * Convert the given DOM point to a DOM point in non-generated contents.
+ *
+ * If aDOMPoint is in ::before, the result is immediately after it.
+ * If aDOMPoint is in ::after, the result is immediately before it.
+ */
+static DOMPoint ClosestNotGeneratedDOMPoint(const DOMPoint& aDOMPoint,
+                                            nsIContent* aElementContent) {
+  MOZ_ASSERT(aDOMPoint.node, "The node must not be null");
+
+  // ::before pseudo element
+  if (aElementContent &&
+      aElementContent->IsGeneratedContentContainerForBefore()) {
+    MOZ_ASSERT(aElementContent->GetParent(),
+               "::before must have parent element");
+    // The first child of its parent (i.e., immediately after the ::before) is
+    // good point for a DOM range.
+    return DOMPoint(aElementContent->GetParent(), 0);
+  }
+
+  // ::after pseudo element
+  if (aElementContent &&
+      aElementContent->IsGeneratedContentContainerForAfter()) {
+    MOZ_ASSERT(aElementContent->GetParent(),
+               "::after must have parent element");
+    // The end of its parent (i.e., immediately before the ::after) is good
+    // point for a DOM range.
+    return DOMPoint(aElementContent->GetParent(),
+                    aElementContent->GetParent()->GetChildCount());
+  }
+
+  return aDOMPoint;
+}
+
+/**
+ * GetElementAsContentOf() returns a content representing an element which is
+ * or includes aNode.
+ *
+ * XXX This method is enough to retrieve ::before or ::after pseudo element.
+ *     So, if you want to use this for other purpose, you might need to check
+ *     ancestors too.
+ */
+static nsIContent* GetElementAsContentOf(nsINode* aNode) {
+  if (auto* element = dom::Element::FromNode(aNode)) {
+    return element;
+  }
+  return aNode->GetParentElement();
+}
+
+bool TextRange::AssignDOMRange(nsRange* aRange, bool* aReversed) const {
+  MOZ_ASSERT(mRoot->IsLocal(), "Not supported for RemoteAccessible");
+  bool reversed = EndPoint() < StartPoint();
+  if (aReversed) {
+    *aReversed = reversed;
+  }
+
+  HyperTextAccessible* startHyper = mStartContainer->AsLocal()->AsHyperText();
+  HyperTextAccessible* endHyper = mEndContainer->AsLocal()->AsHyperText();
+  DOMPoint startPoint = reversed ? endHyper->OffsetToDOMPoint(mEndOffset)
+                                 : startHyper->OffsetToDOMPoint(mStartOffset);
+  if (!startPoint.node) {
+    return false;
+  }
+
+  // HyperTextAccessible manages pseudo elements generated by ::before or
+  // ::after.  However, contents of them are not in the DOM tree normally.
+  // Therefore, they are not selectable and editable.  So, when this creates
+  // a DOM range, it should not start from nor end in any pseudo contents.
+
+  nsIContent* container = GetElementAsContentOf(startPoint.node);
+  DOMPoint startPointForDOMRange =
+      ClosestNotGeneratedDOMPoint(startPoint, container);
+  aRange->SetStart(startPointForDOMRange.node, startPointForDOMRange.idx);
+
+  // If the caller wants collapsed range, let's collapse the range to its start.
+  if (mEndContainer == mStartContainer && mEndOffset == mStartOffset) {
+    aRange->Collapse(true);
+    return true;
+  }
+
+  DOMPoint endPoint = reversed ? startHyper->OffsetToDOMPoint(mStartOffset)
+                               : endHyper->OffsetToDOMPoint(mEndOffset);
+  if (!endPoint.node) {
+    return false;
+  }
+
+  if (startPoint.node != endPoint.node) {
+    container = GetElementAsContentOf(endPoint.node);
+  }
+
+  DOMPoint endPointForDOMRange =
+      ClosestNotGeneratedDOMPoint(endPoint, container);
+  aRange->SetEnd(endPointForDOMRange.node, endPointForDOMRange.idx);
+  return true;
+}
+
+void TextRange::TextRangesFromSelection(dom::Selection* aSelection,
+                                        nsTArray<TextRange>* aRanges) {
+  MOZ_ASSERT(aRanges->Length() == 0, "TextRange array supposed to be empty");
+
+  aRanges->SetCapacity(aSelection->RangeCount());
+
+  const uint32_t rangeCount = aSelection->RangeCount();
+  for (const uint32_t idx : IntegerRange(rangeCount)) {
+    MOZ_ASSERT(aSelection->RangeCount() == rangeCount);
+    const nsRange* DOMRange = aSelection->GetRangeAt(idx);
+    MOZ_ASSERT(DOMRange);
+    HyperTextAccessible* startContainer =
+        nsAccUtils::GetTextContainer(DOMRange->GetStartContainer());
+    HyperTextAccessible* endContainer =
+        nsAccUtils::GetTextContainer(DOMRange->GetEndContainer());
+    HyperTextAccessible* commonAncestor = nsAccUtils::GetTextContainer(
+        DOMRange->GetClosestCommonInclusiveAncestor());
+    if (!startContainer || !endContainer) {
+      continue;
+    }
+
+    int32_t startOffset = startContainer->DOMPointToOffset(
+        DOMRange->GetStartContainer(), DOMRange->StartOffset(), false);
+    int32_t endOffset = endContainer->DOMPointToOffset(
+        DOMRange->GetEndContainer(), DOMRange->EndOffset(), true);
+
+    TextRange tr(commonAncestor && commonAncestor->IsTextField()
+                     ? commonAncestor
+                     : startContainer->Document(),
+                 startContainer, startOffset, endContainer, endOffset);
+    *(aRanges->AppendElement()) = std::move(tr);
+  }
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// pivate
+
+void TextRange::Set(Accessible* aRoot, Accessible* aStartContainer,
+                    int32_t aStartOffset, Accessible* aEndContainer,
+                    int32_t aEndOffset) {
+  mRoot = aRoot;
+  mStartContainer = aStartContainer;
+  mEndContainer = aEndContainer;
+  mStartOffset = aStartOffset;
+  mEndOffset = aEndOffset;
+}
+
+Accessible* TextRange::CommonParent(Accessible* aAcc1, Accessible* aAcc2,
+                                    nsTArray<Accessible*>* aParents1,
+                                    uint32_t* aPos1,
+                                    nsTArray<Accessible*>* aParents2,
+                                    uint32_t* aPos2) const {
+  if (aAcc1 == aAcc2) {
+    return aAcc1;
+  }
+
+  MOZ_ASSERT(aParents1->Length() == 0 || aParents2->Length() == 0,
+             "Wrong arguments");
+
+  // Build the chain of parents.
+  Accessible* p1 = aAcc1;
+  Accessible* p2 = aAcc2;
+  do {
+    aParents1->AppendElement(p1);
+    p1 = p1->Parent();
+  } while (p1);
+  do {
+    aParents2->AppendElement(p2);
+    p2 = p2->Parent();
+  } while (p2);
+
+  // Find where the parent chain differs
+  *aPos1 = aParents1->Length();
+  *aPos2 = aParents2->Length();
+  Accessible* parent = nullptr;
+  uint32_t len = 0;
+  for (len = std::min(*aPos1, *aPos2); len > 0; --len) {
+    Accessible* child1 = aParents1->ElementAt(--(*aPos1));
+    Accessible* child2 = aParents2->ElementAt(--(*aPos2));
+    if (child1 != child2) break;
+
+    parent = child1;
+  }
+
+  return parent;
+}
+
+}  // namespace a11y
+}  // namespace mozilla