1 files changed, 523 insertions, 0 deletions
diff --git a/accessible/base/nsAccessiblePivot.cpp b/accessible/base/nsAccessiblePivot.cpp
new file mode 100644
index 0000000000..ad25885507
--- /dev/null
+++ b/accessible/base/nsAccessiblePivot.cpp
@@ -0,0 +1,523 @@
+/* -*- 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 "nsAccessiblePivot.h"
+
+#include "HyperTextAccessible.h"
+#include "nsAccUtils.h"
+#include "States.h"
+#include "Pivot.h"
+#include "xpcAccessibleDocument.h"
+#include "nsTArray.h"
+#include "mozilla/Maybe.h"
+
+using namespace mozilla::a11y;
+using mozilla::DebugOnly;
+using mozilla::Maybe;
+
+/**
+ * An object that stores a given traversal rule during the pivot movement.
+ */
+class RuleCache : public PivotRule {
+ public:
+  explicit RuleCache(nsIAccessibleTraversalRule* aRule)
+      : mRule(aRule), mPreFilter{0} {}
+  ~RuleCache() {}
+
+  virtual uint16_t Match(Accessible* aAcc) override;
+
+ private:
+  nsCOMPtr<nsIAccessibleTraversalRule> mRule;
+  Maybe<nsTArray<uint32_t>> mAcceptRoles;
+  uint32_t mPreFilter;
+};
+
+////////////////////////////////////////////////////////////////////////////////
+// nsAccessiblePivot
+
+nsAccessiblePivot::nsAccessiblePivot(LocalAccessible* aRoot)
+    : mRoot(aRoot),
+      mModalRoot(nullptr),
+      mPosition(nullptr),
+      mStartOffset(-1),
+      mEndOffset(-1) {
+  NS_ASSERTION(aRoot, "A root accessible is required");
+}
+
+nsAccessiblePivot::~nsAccessiblePivot() {}
+
+////////////////////////////////////////////////////////////////////////////////
+// nsISupports
+
+NS_IMPL_CYCLE_COLLECTION(nsAccessiblePivot, mRoot, mPosition, mObservers)
+
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsAccessiblePivot)
+  NS_INTERFACE_MAP_ENTRY(nsIAccessiblePivot)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIAccessiblePivot)
+NS_INTERFACE_MAP_END
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(nsAccessiblePivot)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(nsAccessiblePivot)
+
+////////////////////////////////////////////////////////////////////////////////
+// nsIAccessiblePivot
+
+NS_IMETHODIMP
+nsAccessiblePivot::GetRoot(nsIAccessible** aRoot) {
+  NS_ENSURE_ARG_POINTER(aRoot);
+
+  NS_IF_ADDREF(*aRoot = ToXPC(mRoot));
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsAccessiblePivot::GetPosition(nsIAccessible** aPosition) {
+  NS_ENSURE_ARG_POINTER(aPosition);
+
+  NS_IF_ADDREF(*aPosition = ToXPC(mPosition));
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsAccessiblePivot::SetPosition(nsIAccessible* aPosition) {
+  RefPtr<LocalAccessible> position = nullptr;
+
+  if (aPosition) {
+    position = aPosition->ToInternalAccessible();
+    if (!position || !IsDescendantOf(position, GetActiveRoot())) {
+      return NS_ERROR_INVALID_ARG;
+    }
+  }
+
+  // Swap old position with new position, saves us an AddRef/Release.
+  mPosition.swap(position);
+  int32_t oldStart = mStartOffset, oldEnd = mEndOffset;
+  mStartOffset = mEndOffset = -1;
+  NotifyOfPivotChange(position, oldStart, oldEnd,
+                      nsIAccessiblePivot::REASON_NONE,
+                      nsIAccessiblePivot::NO_BOUNDARY, false);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsAccessiblePivot::GetModalRoot(nsIAccessible** aModalRoot) {
+  NS_ENSURE_ARG_POINTER(aModalRoot);
+
+  NS_IF_ADDREF(*aModalRoot = ToXPC(mModalRoot));
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsAccessiblePivot::SetModalRoot(nsIAccessible* aModalRoot) {
+  LocalAccessible* modalRoot = nullptr;
+
+  if (aModalRoot) {
+    modalRoot = aModalRoot->ToInternalAccessible();
+    if (!modalRoot || !IsDescendantOf(modalRoot, mRoot)) {
+      return NS_ERROR_INVALID_ARG;
+    }
+  }
+
+  mModalRoot = modalRoot;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsAccessiblePivot::GetStartOffset(int32_t* aStartOffset) {
+  NS_ENSURE_ARG_POINTER(aStartOffset);
+
+  *aStartOffset = mStartOffset;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsAccessiblePivot::GetEndOffset(int32_t* aEndOffset) {
+  NS_ENSURE_ARG_POINTER(aEndOffset);
+
+  *aEndOffset = mEndOffset;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsAccessiblePivot::SetTextRange(nsIAccessibleText* aTextAccessible,
+                                int32_t aStartOffset, int32_t aEndOffset,
+                                bool aIsFromUserInput, uint8_t aArgc) {
+  NS_ENSURE_ARG(aTextAccessible);
+
+  // Check that start offset is smaller than end offset, and that if a value is
+  // smaller than 0, both should be -1.
+  NS_ENSURE_TRUE(
+      aStartOffset <= aEndOffset &&
+          (aStartOffset >= 0 || (aStartOffset != -1 && aEndOffset != -1)),
+      NS_ERROR_INVALID_ARG);
+
+  nsCOMPtr<nsIAccessible> xpcAcc = do_QueryInterface(aTextAccessible);
+  NS_ENSURE_ARG(xpcAcc);
+
+  RefPtr<LocalAccessible> acc = xpcAcc->ToInternalAccessible();
+  NS_ENSURE_ARG(acc);
+
+  HyperTextAccessible* position = acc->AsHyperText();
+  if (!position || !IsDescendantOf(position, GetActiveRoot())) {
+    return NS_ERROR_INVALID_ARG;
+  }
+
+  // Make sure the given offsets don't exceed the character count.
+  if (aEndOffset > static_cast<int32_t>(position->CharacterCount())) {
+    return NS_ERROR_FAILURE;
+  }
+
+  int32_t oldStart = mStartOffset, oldEnd = mEndOffset;
+  mStartOffset = aStartOffset;
+  mEndOffset = aEndOffset;
+
+  mPosition.swap(acc);
+  NotifyOfPivotChange(acc, oldStart, oldEnd, nsIAccessiblePivot::REASON_NONE,
+                      nsIAccessiblePivot::NO_BOUNDARY,
+                      (aArgc > 0) ? aIsFromUserInput : true);
+
+  return NS_OK;
+}
+
+// Traversal functions
+
+NS_IMETHODIMP
+nsAccessiblePivot::MoveNext(nsIAccessibleTraversalRule* aRule,
+                            nsIAccessible* aAnchor, bool aIncludeStart,
+                            bool aIsFromUserInput, uint8_t aArgc,
+                            bool* aResult) {
+  NS_ENSURE_ARG(aResult);
+  NS_ENSURE_ARG(aRule);
+  *aResult = false;
+
+  LocalAccessible* anchor = mPosition;
+  if (aArgc > 0 && aAnchor) anchor = aAnchor->ToInternalAccessible();
+
+  if (anchor &&
+      (anchor->IsDefunct() || !IsDescendantOf(anchor, GetActiveRoot()))) {
+    return NS_ERROR_NOT_IN_TREE;
+  }
+
+  Pivot pivot(GetActiveRoot());
+  RuleCache rule(aRule);
+  Accessible* newPos =
+      pivot.Next(anchor, rule, (aArgc > 1) ? aIncludeStart : false);
+  if (newPos && newPos->IsLocal()) {
+    *aResult =
+        MovePivotInternal(newPos->AsLocal(), nsIAccessiblePivot::REASON_NEXT,
+                          (aArgc > 2) ? aIsFromUserInput : true);
+  } else if (newPos && newPos->IsRemote()) {
+    // we shouldn't ever end up with a proxy here, but if we do for some
+    // reason something is wrong. we should still return OK if we're null
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsAccessiblePivot::MovePrevious(nsIAccessibleTraversalRule* aRule,
+                                nsIAccessible* aAnchor, bool aIncludeStart,
+                                bool aIsFromUserInput, uint8_t aArgc,
+                                bool* aResult) {
+  NS_ENSURE_ARG(aResult);
+  NS_ENSURE_ARG(aRule);
+  *aResult = false;
+
+  LocalAccessible* anchor = mPosition;
+  if (aArgc > 0 && aAnchor) anchor = aAnchor->ToInternalAccessible();
+
+  if (anchor &&
+      (anchor->IsDefunct() || !IsDescendantOf(anchor, GetActiveRoot()))) {
+    return NS_ERROR_NOT_IN_TREE;
+  }
+
+  Pivot pivot(GetActiveRoot());
+  RuleCache rule(aRule);
+  Accessible* newPos =
+      pivot.Prev(anchor, rule, (aArgc > 1) ? aIncludeStart : false);
+  if (newPos && newPos->IsLocal()) {
+    *aResult =
+        MovePivotInternal(newPos->AsLocal(), nsIAccessiblePivot::REASON_PREV,
+                          (aArgc > 2) ? aIsFromUserInput : true);
+  } else if (newPos && newPos->IsRemote()) {
+    // we shouldn't ever end up with a proxy here, but if we do for some
+    // reason something is wrong. we should still return OK if we're null
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsAccessiblePivot::MoveFirst(nsIAccessibleTraversalRule* aRule,
+                             bool aIsFromUserInput, uint8_t aArgc,
+                             bool* aResult) {
+  NS_ENSURE_ARG(aResult);
+  NS_ENSURE_ARG(aRule);
+
+  LocalAccessible* root = GetActiveRoot();
+  NS_ENSURE_TRUE(root && !root->IsDefunct(), NS_ERROR_NOT_IN_TREE);
+
+  Pivot pivot(GetActiveRoot());
+  RuleCache rule(aRule);
+  Accessible* newPos = pivot.First(rule);
+  if (newPos && newPos->IsLocal()) {
+    *aResult =
+        MovePivotInternal(newPos->AsLocal(), nsIAccessiblePivot::REASON_FIRST,
+                          (aArgc > 0) ? aIsFromUserInput : true);
+  } else if (newPos && newPos->IsRemote()) {
+    // we shouldn't ever end up with a proxy here, but if we do for some
+    // reason something is wrong. we should still return OK if we're null
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsAccessiblePivot::MoveLast(nsIAccessibleTraversalRule* aRule,
+                            bool aIsFromUserInput, uint8_t aArgc,
+                            bool* aResult) {
+  NS_ENSURE_ARG(aResult);
+  NS_ENSURE_ARG(aRule);
+
+  LocalAccessible* root = GetActiveRoot();
+  NS_ENSURE_TRUE(root && !root->IsDefunct(), NS_ERROR_NOT_IN_TREE);
+
+  Pivot pivot(root);
+  RuleCache rule(aRule);
+  Accessible* newPos = pivot.Last(rule);
+  if (newPos && newPos->IsLocal()) {
+    *aResult =
+        MovePivotInternal(newPos->AsLocal(), nsIAccessiblePivot::REASON_LAST,
+                          (aArgc > 0) ? aIsFromUserInput : true);
+  } else if (newPos && newPos->IsRemote()) {
+    // we shouldn't ever end up with a proxy here, but if we do for some
+    // reason something is wrong. we should still return OK if we're null
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsAccessiblePivot::MoveNextByText(TextBoundaryType aBoundary,
+                                  bool aIsFromUserInput, uint8_t aArgc,
+                                  bool* aResult) {
+  NS_ENSURE_ARG(aResult);
+
+  *aResult = false;
+
+  Pivot pivot(GetActiveRoot());
+
+  int32_t newStart = mStartOffset, newEnd = mEndOffset;
+  Accessible* newPos = pivot.NextText(mPosition, &newStart, &newEnd, aBoundary);
+  if (LocalAccessible* localNewPos = newPos ? newPos->AsLocal() : nullptr) {
+    *aResult = true;
+    int32_t oldStart = mStartOffset, oldEnd = mEndOffset;
+    LocalAccessible* oldPos = mPosition;
+    mStartOffset = newStart;
+    mEndOffset = newEnd;
+    mPosition = localNewPos;
+    NotifyOfPivotChange(oldPos, oldStart, oldEnd,
+                        nsIAccessiblePivot::REASON_NEXT, aBoundary,
+                        (aArgc > 0) ? aIsFromUserInput : true);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsAccessiblePivot::MovePreviousByText(TextBoundaryType aBoundary,
+                                      bool aIsFromUserInput, uint8_t aArgc,
+                                      bool* aResult) {
+  NS_ENSURE_ARG(aResult);
+
+  *aResult = false;
+
+  Pivot pivot(GetActiveRoot());
+
+  int32_t newStart = mStartOffset, newEnd = mEndOffset;
+  Accessible* newPos = pivot.PrevText(mPosition, &newStart, &newEnd, aBoundary);
+  if (LocalAccessible* localNewPos = newPos ? newPos->AsLocal() : nullptr) {
+    *aResult = true;
+    int32_t oldStart = mStartOffset, oldEnd = mEndOffset;
+    LocalAccessible* oldPos = mPosition;
+    mStartOffset = newStart;
+    mEndOffset = newEnd;
+    mPosition = localNewPos;
+    NotifyOfPivotChange(oldPos, oldStart, oldEnd,
+                        nsIAccessiblePivot::REASON_PREV, aBoundary,
+                        (aArgc > 0) ? aIsFromUserInput : true);
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsAccessiblePivot::MoveToPoint(nsIAccessibleTraversalRule* aRule, int32_t aX,
+                               int32_t aY, bool aIgnoreNoMatch,
+                               bool aIsFromUserInput, uint8_t aArgc,
+                               bool* aResult) {
+  NS_ENSURE_ARG_POINTER(aResult);
+  NS_ENSURE_ARG_POINTER(aRule);
+
+  *aResult = false;
+
+  LocalAccessible* root = GetActiveRoot();
+  NS_ENSURE_TRUE(root && !root->IsDefunct(), NS_ERROR_NOT_IN_TREE);
+
+  RuleCache rule(aRule);
+  Pivot pivot(root);
+
+  Accessible* newPos = pivot.AtPoint(aX, aY, rule);
+  if ((newPos && newPos->IsLocal()) ||
+      !aIgnoreNoMatch) {  // TODO does this need a proxy check?
+    *aResult = MovePivotInternal(newPos ? newPos->AsLocal() : nullptr,
+                                 nsIAccessiblePivot::REASON_POINT,
+                                 (aArgc > 0) ? aIsFromUserInput : true);
+  } else if (newPos && newPos->IsRemote()) {
+    // we shouldn't ever end up with a proxy here, but if we do for some
+    // reason something is wrong. we should still return OK if we're null
+    return NS_ERROR_FAILURE;
+  }
+
+  return NS_OK;
+}
+
+// Observer functions
+
+NS_IMETHODIMP
+nsAccessiblePivot::AddObserver(nsIAccessiblePivotObserver* aObserver) {
+  NS_ENSURE_ARG(aObserver);
+
+  mObservers.AppendElement(aObserver);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsAccessiblePivot::RemoveObserver(nsIAccessiblePivotObserver* aObserver) {
+  NS_ENSURE_ARG(aObserver);
+
+  return mObservers.RemoveElement(aObserver) ? NS_OK : NS_ERROR_FAILURE;
+}
+
+// Private utility methods
+
+bool nsAccessiblePivot::IsDescendantOf(LocalAccessible* aAccessible,
+                                       LocalAccessible* aAncestor) {
+  if (!aAncestor || aAncestor->IsDefunct()) return false;
+
+  // XXX Optimize with IsInDocument() when appropriate. Blocked by bug 759875.
+  LocalAccessible* accessible = aAccessible;
+  do {
+    if (accessible == aAncestor) return true;
+  } while ((accessible = accessible->LocalParent()));
+
+  return false;
+}
+
+bool nsAccessiblePivot::MovePivotInternal(LocalAccessible* aPosition,
+                                          PivotMoveReason aReason,
+                                          bool aIsFromUserInput) {
+  RefPtr<LocalAccessible> oldPosition = std::move(mPosition);
+  mPosition = aPosition;
+  int32_t oldStart = mStartOffset, oldEnd = mEndOffset;
+  mStartOffset = mEndOffset = -1;
+
+  return NotifyOfPivotChange(oldPosition, oldStart, oldEnd, aReason,
+                             nsIAccessiblePivot::NO_BOUNDARY, aIsFromUserInput);
+}
+
+bool nsAccessiblePivot::NotifyOfPivotChange(LocalAccessible* aOldPosition,
+                                            int32_t aOldStart, int32_t aOldEnd,
+                                            int16_t aReason,
+                                            int16_t aBoundaryType,
+                                            bool aIsFromUserInput) {
+  if (aOldPosition == mPosition && aOldStart == mStartOffset &&
+      aOldEnd == mEndOffset) {
+    return false;
+  }
+
+  nsCOMPtr<nsIAccessible> xpcOldPos = ToXPC(aOldPosition);  // death grip
+  for (nsIAccessiblePivotObserver* obs : mObservers.ForwardRange()) {
+    obs->OnPivotChanged(this, xpcOldPos, aOldStart, aOldEnd, ToXPC(mPosition),
+                        mStartOffset, mEndOffset, aReason, aBoundaryType,
+                        aIsFromUserInput);
+  }
+
+  return true;
+}
+
+uint16_t RuleCache::Match(Accessible* aAcc) {
+  uint16_t result = nsIAccessibleTraversalRule::FILTER_IGNORE;
+
+  if (!mAcceptRoles) {
+    mAcceptRoles.emplace();
+    DebugOnly<nsresult> rv = mRule->GetMatchRoles(*mAcceptRoles);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+    rv = mRule->GetPreFilter(&mPreFilter);
+    MOZ_ASSERT(NS_SUCCEEDED(rv));
+  }
+
+  if (mPreFilter) {
+    uint64_t state = aAcc->State();
+
+    if ((nsIAccessibleTraversalRule::PREFILTER_PLATFORM_PRUNED & mPreFilter) &&
+        nsAccUtils::MustPrune(aAcc)) {
+      result |= nsIAccessibleTraversalRule::FILTER_IGNORE_SUBTREE;
+    }
+
+    if ((nsIAccessibleTraversalRule::PREFILTER_INVISIBLE & mPreFilter) &&
+        (state & states::INVISIBLE)) {
+      return result;
+    }
+
+    if ((nsIAccessibleTraversalRule::PREFILTER_OFFSCREEN & mPreFilter) &&
+        (state & states::OFFSCREEN)) {
+      return result;
+    }
+
+    if ((nsIAccessibleTraversalRule::PREFILTER_NOT_FOCUSABLE & mPreFilter) &&
+        !(state & states::FOCUSABLE)) {
+      return result;
+    }
+
+    if (nsIAccessibleTraversalRule::PREFILTER_TRANSPARENT & mPreFilter) {
+      if (aAcc->Opacity() == 0.0f) {
+        return result | nsIAccessibleTraversalRule::FILTER_IGNORE_SUBTREE;
+      }
+    }
+  }
+
+  if (mAcceptRoles->Length() > 0) {
+    uint32_t accessibleRole = aAcc->Role();
+    bool matchesRole = false;
+    for (uint32_t idx = 0; idx < mAcceptRoles->Length(); idx++) {
+      matchesRole = mAcceptRoles->ElementAt(idx) == accessibleRole;
+      if (matchesRole) break;
+    }
+
+    if (!matchesRole) {
+      return result;
+    }
+  }
+
+  uint16_t matchResult = nsIAccessibleTraversalRule::FILTER_IGNORE;
+
+  DebugOnly<nsresult> rv = mRule->Match(ToXPC(aAcc), &matchResult);
+  MOZ_ASSERT(NS_SUCCEEDED(rv));
+
+  return result | matchResult;
+}