gecko/accessible/src/base/nsAccessibilityUtils.h

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 * Contributor(s):
 *   Alexander Surkov <surkov.alexander@gmail.com> (original author)
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#ifndef nsAccessibilityUtils_h_
#define nsAccessibilityUtils_h_

#include "nsAccessibilityAtoms.h"
#include "nsIAccessible.h"

#include "nsIDOMNode.h"
#include "nsIPersistentProperties2.h"
#include "nsIContent.h"
#include "nsIFrame.h"
#include "nsIDocShellTreeItem.h"
#include "nsPoint.h"

class nsAccUtils
{
public:
  /**
   * Returns value of attribute from the given attributes container.
   *
   * @param aAttributes - attributes container
   * @param aAttrName - the name of requested attribute
   * @param aAttrValue - value of attribute
   */
  static void GetAccAttr(nsIPersistentProperties *aAttributes,
                         nsIAtom *aAttrName,
                         nsAString& aAttrValue);

  /**
   * Set value of attribute for the given attributes container.
   *
   * @param aAttributes - attributes container
   * @param aAttrName - the name of requested attribute
   * @param aAttrValue - new value of attribute
   */
  static void SetAccAttr(nsIPersistentProperties *aAttributes,
                         nsIAtom *aAttrName,
                         const nsAString& aAttrValue);

  /**
   * Return values of group attributes ('level', 'setsize', 'posinset')
   */
  static void GetAccGroupAttrs(nsIPersistentProperties *aAttributes,
                               PRInt32 *aLevel,
                               PRInt32 *aPosInSet,
                               PRInt32 *aSetSize);

  /**
   * Returns true if there are level, posinset and sizeset attributes.
   */
  static PRBool HasAccGroupAttrs(nsIPersistentProperties *aAttributes);

  /**
   * Set group attributes ('level', 'setsize', 'posinset').
   */
  static void SetAccGroupAttrs(nsIPersistentProperties *aAttributes,
                               PRInt32 aLevel,
                               PRInt32 aPosInSet,
                               PRInt32 aSetSize);

  /**
   * Set group attributes - 'level', 'setsize', 'posinset'.
   *
   * @param aNode - XUL element that implements
   *                nsIDOMXULSelectControlItemElement interface
   * @param aAttributes - attributes container
   */
  static void SetAccAttrsForXULSelectControlItem(nsIDOMNode *aNode,
                                                 nsIPersistentProperties *aAttributes);

  /**
   * Return true if the given node has registered event listener of the given
   * type.
   */
  static PRBool HasListener(nsIContent *aContent, const nsAString& aEventType);

  /**
   * Return an accesskey registered on the given element by
   * nsIEventStateManager or 0 if there is no registered accesskey.
   *
   * @param aContent - the given element.
   */
  static PRUint32 GetAccessKeyFor(nsIContent *aContent);

  /**
   * Fire accessible event of the given type for the given accessible.
   */
  static nsresult FireAccEvent(PRUint32 aEventType, nsIAccessible *aAccessible,
                               PRBool aIsAsynch = PR_FALSE);

  /**
   * Is the first passed in node an ancestor of the second?
   * Note: A node is not considered to be the ancestor of itself.
   * @param aPossibleAncestorNode -- node to test for ancestor-ness of aPossibleDescendantNode
   * @param aPossibleDescendantNode -- node to test for descendant-ness of aPossibleAncestorNode
   * @return PR_TRUE if aPossibleAncestorNode is an ancestor of aPossibleDescendantNode
   */
   static PRBool IsAncestorOf(nsIDOMNode *aPossibleAncestorNode,
                              nsIDOMNode *aPossibleDescendantNode);

  /**
    * If an ancestor in this document exists with the given role, return it
    * @param aDescendant Descendant to start search with
    * @param aRole Role to find matching ancestor for
    * @return The ancestor accessible with the given role, or nsnull if no match is found
    */
   static already_AddRefed<nsIAccessible>
     GetAncestorWithRole(nsIAccessible *aDescendant, PRUint32 aRole);

  /**
   * Helper method to scroll range into view, used for implementation of
   * nsIAccessibleText::scrollSubstringTo().
   *
   * @param aFrame        the frame for accessible the range belongs to.
   * @param aStartNode    start node of a range
   * @param aStartOffset  an offset inside the start node
   * @param aEndNode      end node of a range
   * @param aEndOffset    an offset inside the end node
   * @param aScrollType   the place a range should be scrolled to
   */
  static nsresult ScrollSubstringTo(nsIFrame *aFrame,
                                    nsIDOMNode *aStartNode, PRInt32 aStartIndex,
                                    nsIDOMNode *aEndNode, PRInt32 aEndIndex,
                                    PRUint32 aScrollType);

  /**
   * Converts scroll type constant defined in nsIAccessibleScrollType to
   * vertical and horizontal percents.
   */
  static void ConvertScrollTypeToPercents(PRUint32 aScrollType,
                                          PRInt16 *aVPercent,
                                          PRInt16 *aHPercent);

  /**
   * Returns coordinates relative screen for the top level window.
   *
   * @param - aNode - the DOM node hosted in the window.
   */
  static nsIntPoint GetScreenCoordsForWindow(nsIDOMNode *aNode);

  /**
   * Return document shell tree item for the given DOM node.
   */
  static already_AddRefed<nsIDocShellTreeItem>
    GetDocShellTreeItemFor(nsIDOMNode *aNode);

  /**
   * Get the ID for an element, in some types of XML this may not be the ID attribute
   * @param aContent  Node to get the ID for
   * @param aID       Where to put ID string
   * @return          PR_TRUE if there is an ID set for this node
   */
  static PRBool GetID(nsIContent *aContent, nsAString& aID);
};

#endif