gecko/accessible/src/base/nsCoreUtils.h

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 *
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 * for the specific language governing rights and limitations under the
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 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
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 * Portions created by the Initial Developer are Copyright (C) 2007
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 *
 * Contributor(s):
 *   Alexander Surkov <surkov.alexander@gmail.com> (original author)
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#ifndef nsCoreUtils_h_
#define nsCoreUtils_h_

#include "nsAccessibilityAtoms.h"

#include "nsIDOMNode.h"
#include "nsIContent.h"
#include "nsIBoxObject.h"
#include "nsITreeBoxObject.h"
#include "nsITreeColumns.h"

#include "nsIFrame.h"
#include "nsIDocShellTreeItem.h"
#include "nsIArray.h"
#include "nsIMutableArray.h"
#include "nsPoint.h"

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

  /**
   * Dispatch click event to XUL tree cell.
   *
   * @param  aTreeBoxObj  [in] tree box object
   * @param  aRowIndex    [in] row index
   * @param  aColumn      [in] column object
   * @param  aPseudoElm   [in] pseudo elemenet inside the cell, see
   *                       nsITreeBoxObject for available values
   */
  static void DispatchClickEvent(nsITreeBoxObject *aTreeBoxObj,
                                 PRInt32 aRowIndex, nsITreeColumn *aColumn,
                                 const nsCString& aPseudoElt = EmptyCString());

  /**
   * Send mouse event to the given element.
   *
   * @param  aEventType  [in] an event type (see nsGUIEvent.h for constants)
   * @param  aPresShell  [in] the presshell for the given element
   * @param  aContent    [in] the element
   */
  static PRBool DispatchMouseEvent(PRUint32 aEventType,
                                   nsIPresShell *aPresShell,
                                   nsIContent *aContent);

  /**
   * Send mouse event to the given element.
   *
   * @param aEventType   [in] an event type (see nsGUIEvent.h for constants)
   * @param aX           [in] x coordinate in dev pixels
   * @param aY           [in] y coordinate in dev pixels
   * @param aContent     [in] the element
   * @param aFrame       [in] frame of the element
   * @param aPresShell   [in] the presshell for the element
   * @param aRootWidget  [in] the root widget of the element
   */
  static void DispatchMouseEvent(PRUint32 aEventType, PRInt32 aX, PRInt32 aY,
                                 nsIContent *aContent, nsIFrame *aFrame,
                                 nsIPresShell *aPresShell,
                                 nsIWidget *aRootWidget);

  /**
   * 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);

  /**
   * Return DOM element related with the given node, i.e.
   * a) itself if it is DOM element
   * b) parent element if it is text node
   * c) body element if it is HTML document node
   * d) document element if it is document node.
   *
   * @param aNode  [in] the given DOM node
   */
  static already_AddRefed<nsIDOMElement> GetDOMElementFor(nsIDOMNode *aNode);

  /**
   * Return DOM node for the given DOM point.
   */
  static already_AddRefed<nsIDOMNode> GetDOMNodeFromDOMPoint(nsIDOMNode *aNode,
                                                             PRUint32 aOffset);
  /**
   * Return the nsIContent* to check for ARIA attributes on -- this may not
   * always be the DOM node for the accessible. Specifically, for doc
   * accessibles, it is not the document node, but either the root element or
   * <body> in HTML. Similar with GetDOMElementFor() method.
   *
   * @param aDOMNode  DOM node for the accessible that may be affected by ARIA
   * @return          the nsIContent which may have ARIA markup
   */
  static nsIContent *GetRoleContent(nsIDOMNode *aDOMNode);

  /**
   * 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);

  /**
   * Are the first node and the second siblings?
   * @return PR_TRUE if aDOMNode1 and aDOMNode2 have same parent
   */
   static PRBool AreSiblings(nsIDOMNode *aDOMNode1,
                             nsIDOMNode *aDOMNode2);

  /**
   * 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);

  /** Helper method to scroll range into view, used for implementation of
   * nsIAccessibleText::scrollSubstringTo[Point]().
   *
   * @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 aVPercent     how to align vertically, specified in percents
   * @param aHPercent     how to align horizontally, specified in percents
   */
  static nsresult ScrollSubstringTo(nsIFrame *aFrame,
                                    nsIDOMNode *aStartNode, PRInt32 aStartIndex,
                                    nsIDOMNode *aEndNode, PRInt32 aEndIndex,
                                    PRInt16 aVPercent, PRInt16 aHPercent);

  /**
   * Scrolls the given frame to the point, used for implememntation of
   * nsIAccessNode::scrollToPoint and nsIAccessibleText::scrollSubstringToPoint.
   *
   * @param aScrollableFrame  the scrollable frame
   * @param aFrame            the frame to scroll
   * @param aPoint            the point scroll to
   */
  static void ScrollFrameToPoint(nsIFrame *aScrollableFrame,
                                 nsIFrame *aFrame, const nsIntPoint& aPoint);

  /**
   * 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);

  /**
   * Retrun frame for the given DOM element.
   */
  static nsIFrame* GetFrameFor(nsIDOMElement *aElm);

  /**
   * Retrun true if the type of given frame equals to the given frame type.
   *
   * @param aFrame  the frame
   * @param aAtom   the frame type
   */
  static PRBool IsCorrectFrameType(nsIFrame* aFrame, nsIAtom* aAtom);

  /**
   * Return presShell for the document containing the given DOM node.
   */
  static already_AddRefed<nsIPresShell> GetPresShellFor(nsIDOMNode *aNode);

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

  /**
   * 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);

  /**
   * Convert attribute value of the given node to positive integer. If no
   * attribute or wrong value then false is returned.
   */
  static PRBool GetUIntAttr(nsIContent *aContent, nsIAtom *aAttr,
                            PRInt32 *aUInt);

  /**
   * Check if the given element is XLink.
   *
   * @param aContent  the given element
   * @return          PR_TRUE if the given element is XLink
   */
  static PRBool IsXLink(nsIContent *aContent);

  /**
   * Returns language for the given node.
   *
   * @param aContent     [in] the given node
   * @param aRootContent [in] container of the given node
   * @param aLanguage    [out] language
   */
  static void GetLanguageFor(nsIContent *aContent, nsIContent *aRootContent,
                             nsAString& aLanguage);

  /**
   * Return the array of elements the given node is referred to by its
   * IDRefs attribute.
   *
   * @param aContent     [in] the given node
   * @param aAttr        [in] IDRefs attribute on the given node
   * @param aRefElements [out] result array of elements
   */
  static void GetElementsByIDRefsAttr(nsIContent *aContent, nsIAtom *aAttr,
                                      nsIArray **aRefElements);

  /**
   * Return the array of elements having IDRefs that points to the given node.
   *
   * @param  aRootContent  [in] root element to search inside
   * @param  aContent      [in] an element having ID attribute
   * @param  aIDRefsAttr   [in] IDRefs attribute
   * @param  aElements     [out] result array of elements
   */
  static void GetElementsHavingIDRefsAttr(nsIContent *aRootContent,
                                          nsIContent *aContent,
                                          nsIAtom *aIDRefsAttr,
                                          nsIArray **aElements);

  /**
   * Helper method for GetElementsHavingIDRefsAttr.
   */
  static void GetElementsHavingIDRefsAttrImpl(nsIContent *aRootContent,
                                              nsCString& aIdWithSpaces,
                                              nsIAtom *aIDRefsAttr,
                                              nsIMutableArray *aElements);

  /**
   * Return computed styles declaration for the given node.
   */
  static void GetComputedStyleDeclaration(const nsAString& aPseudoElt,
                                          nsIDOMNode *aNode,
                                          nsIDOMCSSStyleDeclaration **aCssDecl);

  /**
   * Search element in neighborhood of the given element by tag name and
   * attribute value that equals to ID attribute of the given element.
   * ID attribute can be either 'id' attribute or 'anonid' if the element is
   * anonymous.
   * The first matched content will be returned.
   *
   * @param aForNode - the given element the search is performed for
   * @param aRelationAttrs - an array of attributes, element is attribute name of searched element, ignored if aAriaProperty passed in
   * @param aAttrNum - how many attributes in aRelationAttrs
   * @param aTagName - tag name of searched element, or nsnull for any -- ignored if aAriaProperty passed in
   * @param aAncestorLevelsToSearch - points how is the neighborhood of the
   *                                  given element big.
   */
  static nsIContent *FindNeighbourPointingToNode(nsIContent *aForNode,
                                                 nsIAtom **aRelationAttrs, 
                                                 PRUint32 aAttrNum,
                                                 nsIAtom *aTagName = nsnull,
                                                 PRUint32 aAncestorLevelsToSearch = 5);

  /**
   * Overloaded version of FindNeighbourPointingToNode to accept only one
   * relation attribute.
   */
  static nsIContent *FindNeighbourPointingToNode(nsIContent *aForNode,
                                                 nsIAtom *aRelationAttr, 
                                                 nsIAtom *aTagName = nsnull,
                                                 PRUint32 aAncestorLevelsToSearch = 5);

  /**
   * Search for element that satisfies the requirements in subtree of the given
   * element. The requirements are tag name, attribute name and value of
   * attribute.
   * The first matched content will be returned.
   *
   * @param aId - value of searched attribute
   * @param aLookContent - element that search is performed inside
   * @param aRelationAttrs - an array of searched attributes
   * @param aAttrNum - how many attributes in aRelationAttrs
   * @param                 if both aAriaProperty and aRelationAttrs are null, then any element with aTagType will do
   * @param aExcludeContent - element that is skiped for search
   * @param aTagType - tag name of searched element, by default it is 'label' --
   *                   ignored if aAriaProperty passed in
   */
  static nsIContent *FindDescendantPointingToID(const nsString *aId,
                                                nsIContent *aLookContent,
                                                nsIAtom **aRelationAttrs,
                                                PRUint32 aAttrNum = 1,
                                                nsIContent *aExcludeContent = nsnull,
                                                nsIAtom *aTagType = nsAccessibilityAtoms::label);

  /**
   * Overloaded version of FindDescendantPointingToID to accept only one
   * relation attribute.
   */
  static nsIContent *FindDescendantPointingToID(const nsString *aId,
                                                nsIContent *aLookContent,
                                                nsIAtom *aRelationAttr,
                                                nsIContent *aExcludeContent = nsnull,
                                                nsIAtom *aTagType = nsAccessibilityAtoms::label);

  // Helper for FindDescendantPointingToID(), same args
  static nsIContent *FindDescendantPointingToIDImpl(nsCString& aIdWithSpaces,
                                                    nsIContent *aLookContent,
                                                    nsIAtom **aRelationAttrs,
                                                    PRUint32 aAttrNum = 1,
                                                    nsIContent *aExcludeContent = nsnull,
                                                    nsIAtom *aTagType = nsAccessibilityAtoms::label);

  /**
   * Return the label element for the given DOM element.
   */
  static nsIContent *GetLabelContent(nsIContent *aForNode);

  /**
   * Return the HTML label element for the given HTML element.
   */
  static nsIContent *GetHTMLLabelContent(nsIContent *aForNode);

  /**
   * Return box object for XUL treechildren element by tree box object.
   */
  static already_AddRefed<nsIBoxObject>
    GetTreeBodyBoxObject(nsITreeBoxObject *aTreeBoxObj);

  /**
   * Return tree box object from any levels DOMNode under the XUL tree.
   */
  static void
    GetTreeBoxObject(nsIDOMNode* aDOMNode, nsITreeBoxObject** aBoxObject);

  /**
   * Return first sensible column for the given tree box object.
   */
  static already_AddRefed<nsITreeColumn>
    GetFirstSensibleColumn(nsITreeBoxObject *aTree);

  /**
   * Return last sensible column for the given tree box object.
   */
  static already_AddRefed<nsITreeColumn>
    GetLastSensibleColumn(nsITreeBoxObject *aTree);

  /**
   * Return sensible columns count for the given tree box object.
   */
  static PRUint32 GetSensibleColumnCount(nsITreeBoxObject *aTree);

  /**
   * Return sensible column at the given index for the given tree box object.
   */
  static already_AddRefed<nsITreeColumn>
    GetSensibleColumnAt(nsITreeBoxObject *aTree, PRUint32 aIndex);

  /**
   * Return next sensible column for the given column.
   */
  static already_AddRefed<nsITreeColumn>
    GetNextSensibleColumn(nsITreeColumn *aColumn);

  /**
   * Return previous sensible column for the given column.
   */
  static already_AddRefed<nsITreeColumn>
    GetPreviousSensibleColumn(nsITreeColumn *aColumn);

  /**
   * Return true if the given column is hidden (i.e. not sensible).
   */
  static PRBool IsColumnHidden(nsITreeColumn *aColumn);

  /**
   * Return true if the given node is table header element.
   */
  static PRBool IsHTMLTableHeader(nsIContent *aContent)
  {
    return aContent->NodeInfo()->Equals(nsAccessibilityAtoms::th) ||
      aContent->HasAttr(kNameSpaceID_None, nsAccessibilityAtoms::scope);
  }

  /**
   * Generates frames for popup subtree.
   *
   * @param aNode    [in] DOM node containing the menupopup element as a child
   * @param aIsAnon  [in] specifies whether popup should be searched inside of
   *                  anonymous or explicit content
   */
  static void GeneratePopupTree(nsIDOMNode *aNode, PRBool aIsAnon = PR_FALSE);
};

#endif