gecko-dev/accessible/base/AccIterator.cpp

/* 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 "AccIterator.h"

#include "AccGroupInfo.h"
#ifdef MOZ_XUL
#  include "XULTreeAccessible.h"
#endif

#include "mozilla/dom/HTMLLabelElement.h"

using namespace mozilla;
using namespace mozilla::a11y;

////////////////////////////////////////////////////////////////////////////////
// AccIterator
////////////////////////////////////////////////////////////////////////////////

AccIterator::AccIterator(const Accessible* aAccessible,
                         filters::FilterFuncPtr aFilterFunc)
    : mFilterFunc(aFilterFunc) {
  mState = new IteratorState(aAccessible);
}

AccIterator::~AccIterator() {
  while (mState) {
    IteratorState* tmp = mState;
    mState = tmp->mParentState;
    delete tmp;
  }
}

Accessible* AccIterator::Next() {
  while (mState) {
    Accessible* child = mState->mParent->GetChildAt(mState->mIndex++);
    if (!child) {
      IteratorState* tmp = mState;
      mState = mState->mParentState;
      delete tmp;

      continue;
    }

    uint32_t result = mFilterFunc(child);
    if (result & filters::eMatch) return child;

    if (!(result & filters::eSkipSubtree)) {
      IteratorState* childState = new IteratorState(child, mState);
      mState = childState;
    }
  }

  return nullptr;
}

////////////////////////////////////////////////////////////////////////////////
// nsAccIterator::IteratorState

AccIterator::IteratorState::IteratorState(const Accessible* aParent,
                                          IteratorState* mParentState)
    : mParent(aParent), mIndex(0), mParentState(mParentState) {}

////////////////////////////////////////////////////////////////////////////////
// RelatedAccIterator
////////////////////////////////////////////////////////////////////////////////

RelatedAccIterator::RelatedAccIterator(DocAccessible* aDocument,
                                       nsIContent* aDependentContent,
                                       nsAtom* aRelAttr)
    : mDocument(aDocument),
      mRelAttr(aRelAttr),
      mProviders(nullptr),
      mBindingParent(nullptr),
      mIndex(0) {
  mBindingParent = aDependentContent->IsInAnonymousSubtree()
                       ? aDependentContent->GetBindingParent()
                       : nullptr;
  nsAtom* IDAttr = mBindingParent ? nsGkAtoms::anonid : nsGkAtoms::id;

  nsAutoString id;
  if (aDependentContent->IsElement() &&
      aDependentContent->AsElement()->GetAttr(kNameSpaceID_None, IDAttr, id)) {
    mProviders = mDocument->GetRelProviders(aDependentContent->AsElement(), id);
  }
}

Accessible* RelatedAccIterator::Next() {
  if (!mProviders) return nullptr;

  while (mIndex < mProviders->Length()) {
    DocAccessible::AttrRelProvider* provider = (*mProviders)[mIndex++];

    // Return related accessible for the given attribute and if the provider
    // content is in the same binding in the case of XBL usage.
    if (provider->mRelAttr == mRelAttr) {
      nsIContent* bindingParent = provider->mContent->IsInAnonymousSubtree()
                                      ? provider->mContent->GetBindingParent()
                                      : nullptr;
      bool inScope = mBindingParent == bindingParent ||
                     mBindingParent == provider->mContent;

      if (inScope) {
        Accessible* related = mDocument->GetAccessible(provider->mContent);
        if (related) return related;

        // If the document content is pointed by relation then return the
        // document itself.
        if (provider->mContent == mDocument->GetContent()) return mDocument;
      }
    }
  }

  return nullptr;
}

////////////////////////////////////////////////////////////////////////////////
// HTMLLabelIterator
////////////////////////////////////////////////////////////////////////////////

HTMLLabelIterator::HTMLLabelIterator(DocAccessible* aDocument,
                                     const Accessible* aAccessible,
                                     LabelFilter aFilter)
    : mRelIter(aDocument, aAccessible->GetContent(), nsGkAtoms::_for),
      mAcc(aAccessible),
      mLabelFilter(aFilter) {}

bool HTMLLabelIterator::IsLabel(Accessible* aLabel) {
  dom::HTMLLabelElement* labelEl =
      dom::HTMLLabelElement::FromNode(aLabel->GetContent());
  return labelEl && labelEl->GetControl() == mAcc->GetContent();
}

Accessible* HTMLLabelIterator::Next() {
  // Get either <label for="[id]"> element which explicitly points to given
  // element, or <label> ancestor which implicitly point to it.
  Accessible* label = nullptr;
  while ((label = mRelIter.Next())) {
    if (IsLabel(label)) {
      return label;
    }
  }

  // Ignore ancestor label on not widget accessible.
  if (mLabelFilter == eSkipAncestorLabel || !mAcc->IsWidget()) return nullptr;

  // Go up tree to get a name of ancestor label if there is one (an ancestor
  // <label> implicitly points to us). Don't go up farther than form or
  // document.
  Accessible* walkUp = mAcc->Parent();
  while (walkUp && !walkUp->IsDoc()) {
    nsIContent* walkUpEl = walkUp->GetContent();
    if (IsLabel(walkUp) &&
        !walkUpEl->AsElement()->HasAttr(kNameSpaceID_None, nsGkAtoms::_for)) {
      mLabelFilter = eSkipAncestorLabel;  // prevent infinite loop
      return walkUp;
    }

    if (walkUpEl->IsHTMLElement(nsGkAtoms::form)) break;

    walkUp = walkUp->Parent();
  }

  return nullptr;
}

////////////////////////////////////////////////////////////////////////////////
// HTMLOutputIterator
////////////////////////////////////////////////////////////////////////////////

HTMLOutputIterator::HTMLOutputIterator(DocAccessible* aDocument,
                                       nsIContent* aElement)
    : mRelIter(aDocument, aElement, nsGkAtoms::_for) {}

Accessible* HTMLOutputIterator::Next() {
  Accessible* output = nullptr;
  while ((output = mRelIter.Next())) {
    if (output->GetContent()->IsHTMLElement(nsGkAtoms::output)) return output;
  }

  return nullptr;
}

////////////////////////////////////////////////////////////////////////////////
// XULLabelIterator
////////////////////////////////////////////////////////////////////////////////

XULLabelIterator::XULLabelIterator(DocAccessible* aDocument,
                                   nsIContent* aElement)
    : mRelIter(aDocument, aElement, nsGkAtoms::control) {}

Accessible* XULLabelIterator::Next() {
  Accessible* label = nullptr;
  while ((label = mRelIter.Next())) {
    if (label->GetContent()->IsXULElement(nsGkAtoms::label)) return label;
  }

  return nullptr;
}

////////////////////////////////////////////////////////////////////////////////
// XULDescriptionIterator
////////////////////////////////////////////////////////////////////////////////

XULDescriptionIterator::XULDescriptionIterator(DocAccessible* aDocument,
                                               nsIContent* aElement)
    : mRelIter(aDocument, aElement, nsGkAtoms::control) {}

Accessible* XULDescriptionIterator::Next() {
  Accessible* descr = nullptr;
  while ((descr = mRelIter.Next())) {
    if (descr->GetContent()->IsXULElement(nsGkAtoms::description)) return descr;
  }

  return nullptr;
}

////////////////////////////////////////////////////////////////////////////////
// IDRefsIterator
////////////////////////////////////////////////////////////////////////////////

IDRefsIterator::IDRefsIterator(DocAccessible* aDoc, nsIContent* aContent,
                               nsAtom* aIDRefsAttr)
    : mContent(aContent), mDoc(aDoc), mCurrIdx(0) {
  if (mContent->IsElement()) {
    mContent->AsElement()->GetAttr(kNameSpaceID_None, aIDRefsAttr, mIDs);
  }
}

const nsDependentSubstring IDRefsIterator::NextID() {
  for (; mCurrIdx < mIDs.Length(); mCurrIdx++) {
    if (!NS_IsAsciiWhitespace(mIDs[mCurrIdx])) break;
  }

  if (mCurrIdx >= mIDs.Length()) return nsDependentSubstring();

  nsAString::index_type idStartIdx = mCurrIdx;
  while (++mCurrIdx < mIDs.Length()) {
    if (NS_IsAsciiWhitespace(mIDs[mCurrIdx])) break;
  }

  return Substring(mIDs, idStartIdx, mCurrIdx++ - idStartIdx);
}

nsIContent* IDRefsIterator::NextElem() {
  while (true) {
    const nsDependentSubstring id = NextID();
    if (id.IsEmpty()) break;

    nsIContent* refContent = GetElem(id);
    if (refContent) return refContent;
  }

  return nullptr;
}

nsIContent* IDRefsIterator::GetElem(const nsDependentSubstring& aID) {
  // Get elements in DOM tree by ID attribute if this is an explicit content.
  // In case of bound element check its anonymous subtree.
  if (!mContent->IsInAnonymousSubtree()) {
    dom::DocumentOrShadowRoot* docOrShadowRoot =
        mContent->GetUncomposedDocOrConnectedShadowRoot();
    if (docOrShadowRoot) {
      dom::Element* refElm = docOrShadowRoot->GetElementById(aID);
      if (refElm || !mContent->GetXBLBinding()) return refElm;
    }
  }

  // If content is in anonymous subtree or an element having anonymous subtree
  // then use "anonid" attribute to get elements in anonymous subtree.

  // Check inside the binding the element is contained in.
  nsIContent* bindingParent = mContent->GetBindingParent();
  if (bindingParent) {
    nsIContent* refElm =
        bindingParent->OwnerDoc()->GetAnonymousElementByAttribute(
            bindingParent, nsGkAtoms::anonid, aID);

    if (refElm) return refElm;
  }

  // Check inside the binding of the element.
  if (mContent->GetXBLBinding()) {
    return mContent->OwnerDoc()->GetAnonymousElementByAttribute(
        mContent, nsGkAtoms::anonid, aID);
  }

  return nullptr;
}

Accessible* IDRefsIterator::Next() {
  nsIContent* nextEl = nullptr;
  while ((nextEl = NextElem())) {
    Accessible* acc = mDoc->GetAccessible(nextEl);
    if (acc) {
      return acc;
    }
  }
  return nullptr;
}

////////////////////////////////////////////////////////////////////////////////
// SingleAccIterator
////////////////////////////////////////////////////////////////////////////////

Accessible* SingleAccIterator::Next() {
  RefPtr<Accessible> nextAcc;
  mAcc.swap(nextAcc);
  if (!nextAcc || nextAcc->IsDefunct()) {
    return nullptr;
  }
  return nextAcc;
}

////////////////////////////////////////////////////////////////////////////////
// ItemIterator
////////////////////////////////////////////////////////////////////////////////

Accessible* ItemIterator::Next() {
  if (mContainer) {
    mAnchor = AccGroupInfo::FirstItemOf(mContainer);
    mContainer = nullptr;
    return mAnchor;
  }

  return mAnchor ? (mAnchor = AccGroupInfo::NextItemTo(mAnchor)) : nullptr;
}

////////////////////////////////////////////////////////////////////////////////
// XULTreeItemIterator
////////////////////////////////////////////////////////////////////////////////

XULTreeItemIterator::XULTreeItemIterator(const XULTreeAccessible* aXULTree,
                                         nsITreeView* aTreeView,
                                         int32_t aRowIdx)
    : mXULTree(aXULTree),
      mTreeView(aTreeView),
      mRowCount(-1),
      mContainerLevel(-1),
      mCurrRowIdx(aRowIdx + 1) {
  mTreeView->GetRowCount(&mRowCount);
  if (aRowIdx != -1) mTreeView->GetLevel(aRowIdx, &mContainerLevel);
}

Accessible* XULTreeItemIterator::Next() {
  while (mCurrRowIdx < mRowCount) {
    int32_t level = 0;
    mTreeView->GetLevel(mCurrRowIdx, &level);

    if (level == mContainerLevel + 1)
      return mXULTree->GetTreeItemAccessible(mCurrRowIdx++);

    if (level <= mContainerLevel) {  // got level up
      mCurrRowIdx = mRowCount;
      break;
    }

    mCurrRowIdx++;
  }

  return nullptr;
}