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-rw-r--r--accessible/base/nsAccessiblePivot.cpp523
1 files changed, 523 insertions, 0 deletions
diff --git a/accessible/base/nsAccessiblePivot.cpp b/accessible/base/nsAccessiblePivot.cpp
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+/* -*- 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;
+}