accessible/src/base/nsAccUtils.h

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  20  * the Initial Developer. All Rights Reserved.
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  22  * Contributor(s):
  23  *   Alexander Surkov <surkov.alexander@gmail.com> (original author)
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  38
  39 #ifndef nsAccUtils_h_
  40 #define nsAccUtils_h_
  41
  42 #include "nsIAccessible.h"
  43 #include "nsIAccessNode.h"
  44 #include "nsIAccessibleDocument.h"
  45 #include "nsIAccessibleRole.h"
  46 #include "nsIAccessibleText.h"
  47 #include "nsARIAMap.h"
  48
  49 #include "nsIDOMNode.h"
  50 #include "nsIPersistentProperties2.h"
  51 #include "nsIContent.h"
  52 #include "nsPoint.h"
  53
  54 class nsAccessNode;
  55
  56 class nsAccUtils
  57 {
  58 public:
  59   /**
  60    * Returns value of attribute from the given attributes container.
  61    *
  62    * @param aAttributes - attributes container
  63    * @param aAttrName - the name of requested attribute
  64    * @param aAttrValue - value of attribute
  65    */
  66   static void GetAccAttr(nsIPersistentProperties *aAttributes,
  67                          nsIAtom *aAttrName,
  68                          nsAString& aAttrValue);
  69
  70   /**
  71    * Set value of attribute for the given attributes container.
  72    *
  73    * @param aAttributes - attributes container
  74    * @param aAttrName - the name of requested attribute
  75    * @param aAttrValue - new value of attribute
  76    */
  77   static void SetAccAttr(nsIPersistentProperties *aAttributes,
  78                          nsIAtom *aAttrName,
  79                          const nsAString& aAttrValue);
  80
  81   /**
  82    * Return values of group attributes ('level', 'setsize', 'posinset')
  83    */
  84   static void GetAccGroupAttrs(nsIPersistentProperties *aAttributes,
  85                                PRInt32 *aLevel,
  86                                PRInt32 *aPosInSet,
  87                                PRInt32 *aSetSize);
  88
  89   /**
  90    * Returns true if there are level, posinset and sizeset attributes.
  91    */
  92   static PRBool HasAccGroupAttrs(nsIPersistentProperties *aAttributes);
  93
  94   /**
  95    * Set group attributes ('level', 'setsize', 'posinset').
  96    */
  97   static void SetAccGroupAttrs(nsIPersistentProperties *aAttributes,
  98                                PRInt32 aLevel,
  99                                PRInt32 aPosInSet,
 100                                PRInt32 aSetSize);
 101
 102   /**
 103    * Set group attributes - 'level', 'setsize', 'posinset'.
 104    *
 105    * @param aNode - XUL element that implements
 106    *                nsIDOMXULSelectControlItemElement interface
 107    * @param aAttributes - attributes container
 108    */
 109   static void SetAccAttrsForXULSelectControlItem(nsIDOMNode *aNode,
 110                                                  nsIPersistentProperties *aAttributes);
 111
 112   /**
 113    * Set group attributes - 'level', 'setsize', 'posinset'.
 114    *
 115    * @param  aNode        XUL element that implements
 116    *                      nsIDOMXULContainerItemElement interface
 117    * @param  aAttributes  attributes container
 118    */
 119   static void SetAccAttrsForXULContainerItem(nsIDOMNode *aNode,
 120                                              nsIPersistentProperties *aAttributes);
 121
 122   /**
 123    * Set container-foo live region attributes for the given node.
 124    *
 125    * @param aAttributes    where to store the attributes
 126    * @param aStartContent  node to start from
 127    * @param aTopContent    node to end at
 128    */
 129   static void SetLiveContainerAttributes(nsIPersistentProperties *aAttributes,
 130                                          nsIContent *aStartContent,
 131                                          nsIContent *aTopContent);
 132
 133   /**
 134    * Return PR_TRUE if the ARIA property should always be exposed as an object
 135    * attribute.
 136    */
 137   static PRBool IsARIAPropForObjectAttr(nsIAtom *aAtom);
 138
 139   /**
 140    * Fire accessible event of the given type for the given accessible.
 141    */
 142   static nsresult FireAccEvent(PRUint32 aEventType, nsIAccessible *aAccessible,
 143                                PRBool aIsAsynch = PR_FALSE);
 144
 145   /**
 146     * If an ancestor in this document exists with the given role, return it
 147     * @param aDescendant Descendant to start search with
 148     * @param aRole Role to find matching ancestor for
 149     * @return The ancestor accessible with the given role, or nsnull if no match is found
 150     */
 151    static already_AddRefed<nsIAccessible>
 152      GetAncestorWithRole(nsIAccessible *aDescendant, PRUint32 aRole);
 153
 154    /**
 155      * For an ARIA tree item , get the accessible that represents its conceptual parent.
 156      * This method will use the correct method for the given way the tree is constructed.
 157      * The conceptual parent is what the user sees as the parent, not the DOM or accessible parent.
 158      * @param aStartTreeItem  The tree item to get the parent for
 159      * @param aStartTreeItemContent  The content node for the tree item
 160      * @param The tree item's parent, or null if none
 161      */
 162    static void
 163      GetARIATreeItemParent(nsIAccessible *aStartTreeItem,
 164                            nsIContent *aStartTreeItemContent,
 165                            nsIAccessible **aTreeItemParent);
 166
 167   /**
 168    * Return text accessible containing focus point of the given selection.
 169    * Used for normal and misspelling selection changes processing.
 170    *
 171    * @param aSelection  [in] the given selection
 172    * @param aNode       [out, optional] the DOM node of text accessible
 173    * @return            text accessible
 174    */
 175   static already_AddRefed<nsIAccessibleText>
 176     GetTextAccessibleFromSelection(nsISelection *aSelection,
 177                                    nsIDOMNode **aNode = nsnull);
 178
 179   /**
 180    * Converts the given coordinates to coordinates relative screen.
 181    *
 182    * @param aX               [in] the given x coord
 183    * @param aY               [in] the given y coord
 184    * @param aCoordinateType  [in] specifies coordinates origin (refer to
 185    *                         nsIAccessibleCoordinateType)
 186    * @param aAccessNode      [in] the accessible if coordinates are given
 187    *                         relative it.
 188    * @param aCoords          [out] converted coordinates
 189    */
 190   static nsresult ConvertToScreenCoords(PRInt32 aX, PRInt32 aY,
 191                                         PRUint32 aCoordinateType,
 192                                         nsIAccessNode *aAccessNode,
 193                                         nsIntPoint *aCoords);
 194
 195   /**
 196    * Converts the given coordinates relative screen to another coordinate
 197    * system.
 198    *
 199    * @param aX               [in, out] the given x coord
 200    * @param aY               [in, out] the given y coord
 201    * @param aCoordinateType  [in] specifies coordinates origin (refer to
 202    *                         nsIAccessibleCoordinateType)
 203    * @param aAccessNode      [in] the accessible if coordinates are given
 204    *                         relative it
 205    */
 206   static nsresult ConvertScreenCoordsTo(PRInt32 *aX, PRInt32 *aY,
 207                                         PRUint32 aCoordinateType,
 208                                         nsIAccessNode *aAccessNode);
 209
 210   /**
 211    * Returns coordinates relative screen for the top level window.
 212    *
 213    * @param aAccessNode  the accessible hosted in the window
 214    */
 215   static nsIntPoint GetScreenCoordsForWindow(nsIAccessNode *aAccessNode);
 216
 217   /**
 218    * Returns coordinates relative screen for the parent of the given accessible.
 219    *
 220    * @param aAccessNode  the accessible
 221    */
 222   static nsIntPoint GetScreenCoordsForParent(nsIAccessNode *aAccessNode);
 223
 224   /**
 225    * Get the role map entry for a given DOM node. This will use the first
 226    * ARIA role if the role attribute provides a space delimited list of roles.
 227    * @param aNode  The DOM node to get the role map entry for
 228    * @return       A pointer to the role map entry for the ARIA role, or nsnull if none
 229    */
 230   static nsRoleMapEntry* GetRoleMapEntry(nsIDOMNode *aNode);
 231
 232   /**
 233    * Return the role of the given accessible.
 234    */
 235   static PRUint32 Role(nsIAccessible *aAcc)
 236   {
 237     PRUint32 role = nsIAccessibleRole::ROLE_NOTHING;
 238     if (aAcc)
 239       aAcc->GetFinalRole(&role);
 240
 241     return role;
 242   }
 243
 244   /**
 245    * Return the state for the given accessible.
 246    */
 247   static PRUint32 State(nsIAccessible *aAcc)
 248   {
 249     PRUint32 state = 0;
 250     if (aAcc)
 251       aAcc->GetState(&state, nsnull);
 252
 253     return state;
 254   }
 255
 256   /**
 257    * Query nsAccessNode from the given nsIAccessible.
 258    */
 259   static already_AddRefed<nsAccessNode>
 260     QueryAccessNode(nsIAccessible *aAccessible)
 261   {
 262     nsAccessNode* accessNode = nsnull;
 263     if (aAccessible)
 264       CallQueryInterface(aAccessible, &accessNode);
 265
 266     return accessNode;
 267   }
 268
 269   /**
 270    * Query nsAccessNode from the given nsIAccessNode.
 271    */
 272   static already_AddRefed<nsAccessNode>
 273     QueryAccessNode(nsIAccessNode *aAccessNode)
 274   {
 275     nsAccessNode* accessNode = nsnull;
 276     if (aAccessNode)
 277       CallQueryInterface(aAccessNode, &accessNode);
 278
 279     return accessNode;
 280   }
 281
 282   /**
 283    * Query nsAccessNode from the given nsIAccessNode.
 284    */
 285   static already_AddRefed<nsAccessNode>
 286     QueryAccessNode(nsIAccessibleDocument *aAccessibleDocument)
 287   {
 288     nsAccessNode* accessNode = nsnull;
 289     if (aAccessibleDocument)
 290       CallQueryInterface(aAccessibleDocument, &accessNode);
 291
 292     return accessNode;
 293   }
 294
 295 #ifdef DEBUG_A11Y
 296   /**
 297    * Detect whether the given accessible object implements nsIAccessibleText,
 298    * when it is text or has text child node.
 299    */
 300   static PRBool IsTextInterfaceSupportCorrect(nsIAccessible *aAccessible);
 301 #endif
 302
 303   /**
 304    * Return true if the given accessible has text role.
 305    */
 306   static PRBool IsText(nsIAccessible *aAcc)
 307   {
 308     PRUint32 role = Role(aAcc);
 309     return role == nsIAccessibleRole::ROLE_TEXT_LEAF ||
 310            role == nsIAccessibleRole::ROLE_STATICTEXT;
 311   }
 312
 313   /**
 314    * Return text length of the given accessible, return -1 on failure.
 315    */
 316   static PRInt32 TextLength(nsIAccessible *aAccessible);
 317
 318   /**
 319    * Return true if the given accessible is embedded object.
 320    */
 321   static PRBool IsEmbeddedObject(nsIAccessible *aAcc)
 322   {
 323     PRUint32 role = Role(aAcc);
 324     return role != nsIAccessibleRole::ROLE_TEXT_LEAF &&
 325            role != nsIAccessibleRole::ROLE_WHITESPACE &&
 326            role != nsIAccessibleRole::ROLE_STATICTEXT;
 327   }
 328
 329   /**
 330    * Return true if the given accessible hasn't children.
 331    */
 332   static PRBool IsLeaf(nsIAccessible *aAcc)
 333   {
 334     PRInt32 numChildren;
 335     aAcc->GetChildCount(&numChildren);
 336     return numChildren > 0;
 337   }
 338
 339   /**
 340    * Return true if the given accessible can't have children. Used when exposing
 341    * to platform accessibility APIs, should the children be pruned off?
 342    */
 343   static PRBool MustPrune(nsIAccessible *aAccessible);
 344
 345   /**
 346    * Return true if the given node can be accessible and attached to
 347    * the document's accessible tree.
 348    */
 349   static PRBool IsNodeRelevant(nsIDOMNode *aNode);
 350
 351   /**
 352    * Return multiselectable parent for the given selectable accessible if any.
 353    */
 354   static already_AddRefed<nsIAccessible> GetMultiSelectFor(nsIDOMNode *aNode);
 355 };
 356
 357 #endif