accessible/base/nsAccUtils.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef nsAccUtils_h_
   7 #define nsAccUtils_h_
   8
   9 #include "mozilla/a11y/LocalAccessible.h"
  10 #include "mozilla/a11y/DocManager.h"
  11
  12 #include "nsAccessibilityService.h"
  13 #include "nsCoreUtils.h"
  14
  15 #include "nsIDocShell.h"
  16 #include "nsPoint.h"
  17
  18 namespace mozilla {
  19
  20 class PresShell;
  21
  22 namespace dom {
  23 class Element;
  24 }
  25
  26 namespace a11y {
  27
  28 class HyperTextAccessible;
  29 class DocAccessible;
  30 class Attribute;
  31
  32 class nsAccUtils {
  33  public:
  34   /**
  35    * Set group attributes ('level', 'setsize', 'posinset').
  36    */
  37   static void SetAccGroupAttrs(AccAttributes* aAttributes, int32_t aLevel,
  38                                int32_t aSetSize, int32_t aPosInSet);
  39
  40   /**
  41    * Compute group level for nsIDOMXULContainerItemElement node.
  42    */
  43   static int32_t GetLevelForXULContainerItem(nsIContent* aContent);
  44
  45   /**
  46    * Set container-foo live region attributes for the given node.
  47    *
  48    * @param aAttributes    where to store the attributes
  49    * @param aStartAcc  Accessible to start from
  50    */
  51   static void SetLiveContainerAttributes(AccAttributes* aAttributes,
  52                                          Accessible* aStartAcc);
  53
  54   /**
  55    * Any ARIA property of type boolean or NMTOKEN is undefined if the ARIA
  56    * property is not present, or is "" or "undefined". Do not call
  57    * this method for properties of type string, decimal, IDREF or IDREFS.
  58    *
  59    * Return true if the ARIA property is defined, otherwise false
  60    */
  61   static bool HasDefinedARIAToken(nsIContent* aContent, nsAtom* aAtom);
  62   static bool HasDefinedARIAToken(const AttrArray* aAttrs, nsAtom* aAtom);
  63
  64   /**
  65    * If the given ARIA attribute has a specific known token value, return it.
  66    * If the specification demands for a fallback value for unknown attribute
  67    * values, return that. For all others, return a nullptr.
  68    */
  69   static nsStaticAtom* NormalizeARIAToken(const AttrArray* aAttrs,
  70                                           nsAtom* aAttr);
  71   static nsStaticAtom* NormalizeARIAToken(mozilla::dom::Element* aElement,
  72                                           nsAtom* aAttr);
  73
  74   /**
  75    * Return document accessible for the given DOM node.
  76    */
  77   static DocAccessible* GetDocAccessibleFor(nsINode* aNode) {
  78     return GetAccService()->GetDocAccessible(
  79         nsCoreUtils::GetPresShellFor(aNode));
  80   }
  81
  82   /**
  83    * Return document accessible for the given docshell.
  84    */
  85   static DocAccessible* GetDocAccessibleFor(nsIDocShellTreeItem* aContainer) {
  86     nsCOMPtr<nsIDocShell> docShell(do_QueryInterface(aContainer));
  87     return GetAccService()->GetDocAccessible(docShell->GetPresShell());
  88   }
  89
  90   /**
  91    * Return single or multi selectable container for the given item.
  92    *
  93    * @param  aAccessible  [in] the item accessible
  94    * @param  aState       [in] the state of the item accessible
  95    */
  96   static Accessible* GetSelectableContainer(const Accessible* aAccessible,
  97                                             uint64_t aState);
  98   static LocalAccessible* GetSelectableContainer(LocalAccessible* aAccessible,
  99                                                  uint64_t aState);
 100
 101   /**
 102    * Return a text container accessible for the given node.
 103    */
 104   static HyperTextAccessible* GetTextContainer(nsINode* aNode);
 105
 106   static Accessible* TableFor(Accessible* aRow);
 107   static LocalAccessible* TableFor(LocalAccessible* aRow);
 108
 109   /**
 110    * Return true if the DOM node of a given accessible has a given attribute
 111    * with a value of "true".
 112    */
 113   static bool IsDOMAttrTrue(const LocalAccessible* aAccessible, nsAtom* aAttr);
 114
 115   /**
 116    * Return true if the DOM node of given accessible has aria-selected="true"
 117    * attribute.
 118    */
 119   static inline bool IsARIASelected(const LocalAccessible* aAccessible) {
 120     return IsDOMAttrTrue(aAccessible, nsGkAtoms::aria_selected);
 121   }
 122
 123   /**
 124    * Return true if the DOM node of given accessible has
 125    * aria-multiselectable="true" attribute.
 126    */
 127   static inline bool IsARIAMultiSelectable(const LocalAccessible* aAccessible) {
 128     return IsDOMAttrTrue(aAccessible, nsGkAtoms::aria_multiselectable);
 129   }
 130
 131   /**
 132    * Converts the given coordinates to coordinates relative screen.
 133    *
 134    * @param aX               [in] the given x coord in dev pixels
 135    * @param aY               [in] the given y coord in dev pixels
 136    * @param aCoordinateType  [in] specifies coordinates origin (refer to
 137    *                         nsIAccessibleCoordinateType)
 138    * @param aAccessible      [in] the accessible if coordinates are given
 139    *                         relative it.
 140    * @return converted coordinates
 141    */
 142   static LayoutDeviceIntPoint ConvertToScreenCoords(int32_t aX, int32_t aY,
 143                                                     uint32_t aCoordinateType,
 144                                                     Accessible* aAccessible);
 145
 146   /**
 147    * Converts the given coordinates relative screen to another coordinate
 148    * system.
 149    *
 150    * @param aX               [in, out] the given x coord in dev pixels
 151    * @param aY               [in, out] the given y coord in dev pixels
 152    * @param aCoordinateType  [in] specifies coordinates origin (refer to
 153    *                         nsIAccessibleCoordinateType)
 154    * @param aAccessible      [in] the accessible if coordinates are given
 155    *                         relative it
 156    */
 157   static void ConvertScreenCoordsTo(int32_t* aX, int32_t* aY,
 158                                     uint32_t aCoordinateType,
 159                                     Accessible* aAccessible);
 160
 161   /**
 162    * Returns screen-relative coordinates (in dev pixels) for the parent of the
 163    * given accessible.
 164    *
 165    * @param [in] aAccessible  the accessible
 166    */
 167   static LayoutDeviceIntPoint GetScreenCoordsForParent(Accessible* aAccessible);
 168
 169   /**
 170    * Returns coordinates in device pixels relative screen for the top level
 171    * window.
 172    *
 173    * @param aAccessible the acc hosted in the window.
 174    */
 175   static mozilla::LayoutDeviceIntPoint GetScreenCoordsForWindow(
 176       mozilla::a11y::Accessible* aAccessible);
 177
 178   /**
 179    * Get the 'live' or 'container-live' object attribute value from the given
 180    * ELiveAttrRule constant.
 181    *
 182    * @param  aRule   [in] rule constant (see ELiveAttrRule in nsAccMap.h)
 183    * @param  aValue  [out] object attribute value
 184    *
 185    * @return         true if object attribute should be exposed
 186    */
 187   static bool GetLiveAttrValue(uint32_t aRule, nsAString& aValue);
 188
 189 #ifdef DEBUG
 190   /**
 191    * Detect whether the given accessible object implements nsIAccessibleText,
 192    * when it is text or has text child node.
 193    */
 194   static bool IsTextInterfaceSupportCorrect(LocalAccessible* aAccessible);
 195 #endif
 196
 197   /**
 198    * Return text length of the given accessible, return 0 on failure.
 199    */
 200   static uint32_t TextLength(Accessible* aAccessible);
 201
 202   /**
 203    * Transform nsIAccessibleStates constants to internal state constant.
 204    */
 205   static inline uint64_t To64State(uint32_t aState1, uint32_t aState2) {
 206     return static_cast<uint64_t>(aState1) +
 207            (static_cast<uint64_t>(aState2) << 31);
 208   }
 209
 210   /**
 211    * Transform internal state constant to nsIAccessibleStates constants.
 212    */
 213   static inline void To32States(uint64_t aState64, uint32_t* aState1,
 214                                 uint32_t* aState2) {
 215     *aState1 = aState64 & 0x7fffffff;
 216     if (aState2) *aState2 = static_cast<uint32_t>(aState64 >> 31);
 217   }
 218
 219   static uint32_t To32States(uint64_t aState, bool* aIsExtra) {
 220     uint32_t extraState = aState >> 31;
 221     *aIsExtra = !!extraState;
 222     return extraState ? extraState : aState;
 223   }
 224
 225   /**
 226    * Return true if the given accessible can't have children. Used when exposing
 227    * to platform accessibility APIs, should the children be pruned off?
 228    */
 229   static bool MustPrune(Accessible* aAccessible);
 230
 231   /**
 232    * Return true if the given accessible is within an ARIA live region; i.e.
 233    * the container-live attribute would be something other than "off" or empty.
 234    */
 235   static bool IsARIALive(const LocalAccessible* aAccessible);
 236
 237   /**
 238    * Get the document Accessible which owns a given Accessible.
 239    * This function is needed because there is no unified base class for local
 240    * and remote documents.
 241    * If aAcc is null, null will be returned.
 242    */
 243   static Accessible* DocumentFor(Accessible* aAcc);
 244
 245   /**
 246    * Get an Accessible in a given document by its unique id.
 247    * An Accessible's id can be obtained using Accessible::ID.
 248    * This function is needed because there is no unified base class for local
 249    * and remote documents.
 250    * If aDoc is nul, null will be returned.
 251    */
 252   static Accessible* GetAccessibleByID(Accessible* aDoc, uint64_t aID);
 253
 254   /**
 255    * Get the URL for a given document.
 256    * This function is needed because there is no unified base class for local
 257    * and remote documents.
 258    */
 259   static void DocumentURL(Accessible* aDoc, nsAString& aURL);
 260
 261   /**
 262    * Accessors for element attributes that are aware of CustomElement ARIA
 263    * accessibility defaults. If the element does not have the provided
 264    * attribute defined directly on it, we will then attempt to fetch the
 265    * default instead.
 266    */
 267   static const AttrArray* GetARIADefaults(dom::Element* aElement);
 268   static bool HasARIAAttr(dom::Element* aElement, const nsAtom* aName);
 269   static bool GetARIAAttr(dom::Element* aElement, const nsAtom* aName,
 270                           nsAString& aResult);
 271   static const nsAttrValue* GetARIAAttr(dom::Element* aElement,
 272                                         const nsAtom* aName);
 273   static bool ARIAAttrValueIs(dom::Element* aElement, const nsAtom* aName,
 274                               const nsAString& aValue,
 275                               nsCaseTreatment aCaseSensitive);
 276   static bool ARIAAttrValueIs(dom::Element* aElement, const nsAtom* aName,
 277                               const nsAtom* aValue,
 278                               nsCaseTreatment aCaseSensitive);
 279   static int32_t FindARIAAttrValueIn(dom::Element* aElement,
 280                                      const nsAtom* aName,
 281                                      AttrArray::AttrValuesArray* aValues,
 282                                      nsCaseTreatment aCaseSensitive);
 283 };
 284
 285 }  // namespace a11y
 286 }  // namespace mozilla
 287
 288 #endif