gecko-dev/accessible/base/nsAccUtils.cpp

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 "nsAccUtils.h"

#include "Accessible-inl.h"
#include "ARIAMap.h"
#include "nsAccessibilityService.h"
#include "nsCoreUtils.h"
#include "DocAccessible.h"
#include "HyperTextAccessible.h"
#include "nsIAccessibleTypes.h"
#include "Role.h"
#include "States.h"
#include "TextLeafAccessible.h"

#include "nsIDOMXULContainerElement.h"
#include "nsIPersistentProperties2.h"
#include "mozilla/a11y/PDocAccessibleChild.h"
#include "mozilla/dom/Element.h"

using namespace mozilla;
using namespace mozilla::a11y;

void nsAccUtils::GetAccAttr(nsIPersistentProperties* aAttributes,
                            nsAtom* aAttrName, nsAString& aAttrValue) {
  aAttrValue.Truncate();

  aAttributes->GetStringProperty(nsAtomCString(aAttrName), aAttrValue);
}

void nsAccUtils::SetAccAttr(nsIPersistentProperties* aAttributes,
                            nsAtom* aAttrName, const nsAString& aAttrValue) {
  nsAutoString oldValue;
  aAttributes->SetStringProperty(nsAtomCString(aAttrName), aAttrValue,
                                 oldValue);
}

void nsAccUtils::SetAccAttr(nsIPersistentProperties* aAttributes,
                            nsAtom* aAttrName, nsAtom* aAttrValue) {
  nsAutoString oldValue;
  aAttributes->SetStringProperty(nsAtomCString(aAttrName),
                                 nsAtomString(aAttrValue), oldValue);
}

void nsAccUtils::SetAccGroupAttrs(nsIPersistentProperties* aAttributes,
                                  int32_t aLevel, int32_t aSetSize,
                                  int32_t aPosInSet) {
  nsAutoString value;

  if (aLevel) {
    value.AppendInt(aLevel);
    SetAccAttr(aAttributes, nsGkAtoms::level, value);
  }

  if (aSetSize && aPosInSet) {
    value.Truncate();
    value.AppendInt(aPosInSet);
    SetAccAttr(aAttributes, nsGkAtoms::posinset, value);

    value.Truncate();
    value.AppendInt(aSetSize);
    SetAccAttr(aAttributes, nsGkAtoms::setsize, value);
  }
}

int32_t nsAccUtils::GetDefaultLevel(const Accessible* aAccessible) {
  roles::Role role = aAccessible->Role();

  if (role == roles::OUTLINEITEM) return 1;

  if (role == roles::ROW) {
    Accessible* parent = aAccessible->Parent();
    // It is a row inside flatten treegrid. Group level is always 1 until it
    // is overriden by aria-level attribute.
    if (parent && parent->Role() == roles::TREE_TABLE) return 1;
  }

  return 0;
}

int32_t nsAccUtils::GetARIAOrDefaultLevel(const Accessible* aAccessible) {
  int32_t level = 0;
  nsCoreUtils::GetUIntAttr(aAccessible->GetContent(), nsGkAtoms::aria_level,
                           &level);

  if (level != 0) return level;

  return GetDefaultLevel(aAccessible);
}

int32_t nsAccUtils::GetLevelForXULContainerItem(nsIContent* aContent) {
  nsCOMPtr<nsIDOMXULContainerItemElement> item =
      aContent->AsElement()->AsXULContainerItem();
  if (!item) return 0;

  nsCOMPtr<Element> containerElement;
  item->GetParentContainer(getter_AddRefs(containerElement));
  nsCOMPtr<nsIDOMXULContainerElement> container =
      containerElement ? containerElement->AsXULContainer() : nullptr;
  if (!container) return 0;

  // Get level of the item.
  int32_t level = -1;
  while (container) {
    level++;

    container->GetParentContainer(getter_AddRefs(containerElement));
    container = containerElement ? containerElement->AsXULContainer() : nullptr;
  }

  return level;
}

void nsAccUtils::SetLiveContainerAttributes(
    nsIPersistentProperties* aAttributes, nsIContent* aStartContent,
    dom::Element* aTopEl) {
  nsAutoString live, relevant, busy;
  nsIContent* ancestor = aStartContent;
  while (ancestor) {
    // container-relevant attribute
    if (relevant.IsEmpty() &&
        HasDefinedARIAToken(ancestor, nsGkAtoms::aria_relevant) &&
        ancestor->AsElement()->GetAttr(kNameSpaceID_None,
                                       nsGkAtoms::aria_relevant, relevant))
      SetAccAttr(aAttributes, nsGkAtoms::containerRelevant, relevant);

    // container-live, and container-live-role attributes
    if (live.IsEmpty()) {
      const nsRoleMapEntry* role = nullptr;
      if (ancestor->IsElement()) {
        role = aria::GetRoleMap(ancestor->AsElement());
      }
      if (HasDefinedARIAToken(ancestor, nsGkAtoms::aria_live)) {
        ancestor->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::aria_live,
                                       live);
      } else if (role) {
        GetLiveAttrValue(role->liveAttRule, live);
      }
      if (!live.IsEmpty()) {
        SetAccAttr(aAttributes, nsGkAtoms::containerLive, live);
        if (role) {
          SetAccAttr(aAttributes, nsGkAtoms::containerLiveRole,
                     role->ARIARoleString());
        }
      }
    }

    // container-atomic attribute
    if (ancestor->IsElement() && ancestor->AsElement()->AttrValueIs(
                                     kNameSpaceID_None, nsGkAtoms::aria_atomic,
                                     nsGkAtoms::_true, eCaseMatters)) {
      SetAccAttr(aAttributes, nsGkAtoms::containerAtomic,
                 NS_LITERAL_STRING("true"));
    }

    // container-busy attribute
    if (busy.IsEmpty() && HasDefinedARIAToken(ancestor, nsGkAtoms::aria_busy) &&
        ancestor->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::aria_busy,
                                       busy))
      SetAccAttr(aAttributes, nsGkAtoms::containerBusy, busy);

    if (ancestor == aTopEl) break;

    ancestor = ancestor->GetParent();
    if (!ancestor) ancestor = aTopEl;  // Use <body>/<frameset>
  }
}

bool nsAccUtils::HasDefinedARIAToken(nsIContent* aContent, nsAtom* aAtom) {
  NS_ASSERTION(aContent, "aContent is null in call to HasDefinedARIAToken!");

  if (!aContent->IsElement()) return false;

  Element* element = aContent->AsElement();
  if (!element->HasAttr(kNameSpaceID_None, aAtom) ||
      element->AttrValueIs(kNameSpaceID_None, aAtom, nsGkAtoms::_empty,
                           eCaseMatters) ||
      element->AttrValueIs(kNameSpaceID_None, aAtom, nsGkAtoms::_undefined,
                           eCaseMatters)) {
    return false;
  }
  return true;
}

nsStaticAtom* nsAccUtils::GetARIAToken(dom::Element* aElement, nsAtom* aAttr) {
  if (!HasDefinedARIAToken(aElement, aAttr)) return nsGkAtoms::_empty;

  static Element::AttrValuesArray tokens[] = {
      nsGkAtoms::_false, nsGkAtoms::_true, nsGkAtoms::mixed, nullptr};

  int32_t idx =
      aElement->FindAttrValueIn(kNameSpaceID_None, aAttr, tokens, eCaseMatters);
  if (idx >= 0) return tokens[idx];

  return nullptr;
}

nsStaticAtom* nsAccUtils::NormalizeARIAToken(dom::Element* aElement,
                                             nsAtom* aAttr) {
  if (!HasDefinedARIAToken(aElement, aAttr)) {
    return nsGkAtoms::_empty;
  }

  if (aAttr == nsGkAtoms::aria_current) {
    static Element::AttrValuesArray tokens[] = {
        nsGkAtoms::page, nsGkAtoms::step, nsGkAtoms::location_,
        nsGkAtoms::date, nsGkAtoms::time, nsGkAtoms::_true,
        nullptr};
    int32_t idx = aElement->FindAttrValueIn(kNameSpaceID_None, aAttr, tokens,
                                            eCaseMatters);
    // If the token is present, return it, otherwise TRUE as per spec.
    return (idx >= 0) ? tokens[idx] : nsGkAtoms::_true;
  }

  return nullptr;
}

Accessible* nsAccUtils::GetSelectableContainer(Accessible* aAccessible,
                                               uint64_t aState) {
  if (!aAccessible) return nullptr;

  if (!(aState & states::SELECTABLE)) return nullptr;

  Accessible* parent = aAccessible;
  while ((parent = parent->Parent()) && !parent->IsSelect()) {
    if (parent->Role() == roles::PANE) return nullptr;
  }
  return parent;
}

bool nsAccUtils::IsDOMAttrTrue(const Accessible* aAccessible, nsAtom* aAttr) {
  dom::Element* el = aAccessible->Elm();
  return el && el->AttrValueIs(kNameSpaceID_None, aAttr, nsGkAtoms::_true,
                               eCaseMatters);
}

Accessible* nsAccUtils::TableFor(Accessible* aRow) {
  if (aRow) {
    Accessible* table = aRow->Parent();
    if (table) {
      roles::Role tableRole = table->Role();
      if (tableRole == roles::GROUPING) {  // if there's a rowgroup.
        table = table->Parent();
        if (table) tableRole = table->Role();
      }

      return (tableRole == roles::TABLE || tableRole == roles::TREE_TABLE ||
              tableRole == roles::MATHML_TABLE)
                 ? table
                 : nullptr;
    }
  }

  return nullptr;
}

HyperTextAccessible* nsAccUtils::GetTextContainer(nsINode* aNode) {
  // Get text accessible containing the result node.
  DocAccessible* doc = GetAccService()->GetDocAccessible(aNode->OwnerDoc());
  Accessible* accessible = doc ? doc->GetAccessibleOrContainer(aNode) : nullptr;
  if (!accessible) return nullptr;

  do {
    HyperTextAccessible* textAcc = accessible->AsHyperText();
    if (textAcc) return textAcc;

    accessible = accessible->Parent();
  } while (accessible);

  return nullptr;
}

nsIntPoint nsAccUtils::ConvertToScreenCoords(int32_t aX, int32_t aY,
                                             uint32_t aCoordinateType,
                                             Accessible* aAccessible) {
  nsIntPoint coords(aX, aY);

  switch (aCoordinateType) {
    case nsIAccessibleCoordinateType::COORDTYPE_SCREEN_RELATIVE:
      break;

    case nsIAccessibleCoordinateType::COORDTYPE_WINDOW_RELATIVE: {
      coords += nsCoreUtils::GetScreenCoordsForWindow(aAccessible->GetNode());
      break;
    }

    case nsIAccessibleCoordinateType::COORDTYPE_PARENT_RELATIVE: {
      coords += GetScreenCoordsForParent(aAccessible);
      break;
    }

    default:
      MOZ_ASSERT_UNREACHABLE("invalid coord type!");
  }

  return coords;
}

void nsAccUtils::ConvertScreenCoordsTo(int32_t* aX, int32_t* aY,
                                       uint32_t aCoordinateType,
                                       Accessible* aAccessible) {
  switch (aCoordinateType) {
    case nsIAccessibleCoordinateType::COORDTYPE_SCREEN_RELATIVE:
      break;

    case nsIAccessibleCoordinateType::COORDTYPE_WINDOW_RELATIVE: {
      nsIntPoint coords =
          nsCoreUtils::GetScreenCoordsForWindow(aAccessible->GetNode());
      *aX -= coords.x;
      *aY -= coords.y;
      break;
    }

    case nsIAccessibleCoordinateType::COORDTYPE_PARENT_RELATIVE: {
      nsIntPoint coords = GetScreenCoordsForParent(aAccessible);
      *aX -= coords.x;
      *aY -= coords.y;
      break;
    }

    default:
      MOZ_ASSERT_UNREACHABLE("invalid coord type!");
  }
}

nsIntPoint nsAccUtils::GetScreenCoordsForParent(Accessible* aAccessible) {
  Accessible* parent = aAccessible->Parent();
  if (!parent) return nsIntPoint(0, 0);

  nsIFrame* parentFrame = parent->GetFrame();
  if (!parentFrame) return nsIntPoint(0, 0);

  nsRect rect = parentFrame->GetScreenRectInAppUnits();
  return nsPoint(rect.X(), rect.Y())
      .ToNearestPixels(parentFrame->PresContext()->AppUnitsPerDevPixel());
}

bool nsAccUtils::GetLiveAttrValue(uint32_t aRule, nsAString& aValue) {
  switch (aRule) {
    case eOffLiveAttr:
      aValue = NS_LITERAL_STRING("off");
      return true;
    case ePoliteLiveAttr:
      aValue = NS_LITERAL_STRING("polite");
      return true;
  }

  return false;
}

#ifdef DEBUG

bool nsAccUtils::IsTextInterfaceSupportCorrect(Accessible* aAccessible) {
  // Don't test for accessible docs, it makes us create accessibles too
  // early and fire mutation events before we need to
  if (aAccessible->IsDoc()) return true;

  bool foundText = false;
  uint32_t childCount = aAccessible->ChildCount();
  for (uint32_t childIdx = 0; childIdx < childCount; childIdx++) {
    Accessible* child = aAccessible->GetChildAt(childIdx);
    if (child->IsText()) {
      foundText = true;
      break;
    }
  }

  return !foundText || aAccessible->IsHyperText();
}
#endif

uint32_t nsAccUtils::TextLength(Accessible* aAccessible) {
  if (!aAccessible->IsText()) {
    return 1;
  }

  TextLeafAccessible* textLeaf = aAccessible->AsTextLeaf();
  if (textLeaf) return textLeaf->Text().Length();

  // For list bullets (or anything other accessible which would compute its own
  // text. They don't have their own frame.
  // XXX In the future, list bullets may have frame and anon content, so
  // we should be able to remove this at that point
  nsAutoString text;
  aAccessible->AppendTextTo(text);  // Get all the text
  return text.Length();
}

bool nsAccUtils::MustPrune(Accessible* aAccessible) {
  roles::Role role = aAccessible->Role();

  return
      // Always prune the tree for sliders, as it doesn't make sense for a
      // slider to have descendants and this confuses NVDA.
      role == roles::SLIDER ||
      // Don't prune the tree for certain roles if the tree is more complex than
      // a single text leaf.
      ((role == roles::MENUITEM || role == roles::COMBOBOX_OPTION ||
        role == roles::OPTION || role == roles::ENTRY ||
        role == roles::FLAT_EQUATION || role == roles::PASSWORD_TEXT ||
        role == roles::PUSHBUTTON || role == roles::TOGGLE_BUTTON ||
        role == roles::GRAPHIC || role == roles::PROGRESSBAR ||
        role == roles::SEPARATOR) &&
       aAccessible->ContentChildCount() == 1 &&
       aAccessible->ContentChildAt(0)->IsTextLeaf());
}

bool nsAccUtils::PersistentPropertiesToArray(nsIPersistentProperties* aProps,
                                             nsTArray<Attribute>* aAttributes) {
  if (!aProps) {
    return true;
  }
  nsCOMPtr<nsISimpleEnumerator> propEnum;
  nsresult rv = aProps->Enumerate(getter_AddRefs(propEnum));
  NS_ENSURE_SUCCESS(rv, false);

  bool hasMore;
  while (NS_SUCCEEDED(propEnum->HasMoreElements(&hasMore)) && hasMore) {
    nsCOMPtr<nsISupports> sup;
    rv = propEnum->GetNext(getter_AddRefs(sup));
    NS_ENSURE_SUCCESS(rv, false);

    nsCOMPtr<nsIPropertyElement> propElem(do_QueryInterface(sup));
    NS_ENSURE_TRUE(propElem, false);

    nsAutoCString name;
    rv = propElem->GetKey(name);
    NS_ENSURE_SUCCESS(rv, false);

    nsAutoString value;
    rv = propElem->GetValue(value);
    NS_ENSURE_SUCCESS(rv, false);

    aAttributes->AppendElement(Attribute(name, value));
  }

  return true;
}

bool nsAccUtils::IsARIALive(const Accessible* aAccessible) {
  // Get computed aria-live property based on the closest container with the
  // attribute. Inner nodes override outer nodes within the same
  // document, but nodes in outer documents override nodes in inner documents.
  // This should be the same as the container-live attribute, but we don't need
  // the other container-* attributes, so we can't use the same function.
  nsAutoString live;
  nsIContent* startContent = aAccessible->GetContent();
  while (startContent) {
    dom::Document* doc = startContent->GetComposedDoc();
    if (!doc) {
      break;
    }

    dom::Element* aTopEl = doc->GetRootElement();
    nsIContent* ancestor = startContent;
    while (ancestor) {
      nsAutoString docLive;
      const nsRoleMapEntry* role = nullptr;
      if (ancestor->IsElement()) {
        role = aria::GetRoleMap(ancestor->AsElement());
      }
      if (HasDefinedARIAToken(ancestor, nsGkAtoms::aria_live)) {
        ancestor->AsElement()->GetAttr(kNameSpaceID_None, nsGkAtoms::aria_live,
                                       docLive);
      } else if (role) {
        GetLiveAttrValue(role->liveAttRule, docLive);
      }
      if (!docLive.IsEmpty()) {
        live = docLive;
        break;
      }

      if (ancestor == aTopEl) {
        break;
      }

      ancestor = ancestor->GetParent();
      if (!ancestor) {
        ancestor = aTopEl;  // Use <body>/<frameset>
      }
    }

    // Allow ARIA live region markup from outer documents to override.
    nsCOMPtr<nsIDocShellTreeItem> docShellTreeItem = doc->GetDocShell();
    if (!docShellTreeItem) {
      break;
    }

    nsCOMPtr<nsIDocShellTreeItem> sameTypeParent;
    docShellTreeItem->GetSameTypeParent(getter_AddRefs(sameTypeParent));
    if (!sameTypeParent || sameTypeParent == docShellTreeItem) {
      break;
    }

    dom::Document* parentDoc = doc->GetParentDocument();
    if (!parentDoc) {
      break;
    }

    startContent = parentDoc->FindContentForSubDocument(doc);
  }

  return !live.IsEmpty() && !live.EqualsLiteral("off");
}