accessible/src/base/nsCoreUtils.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* ***** BEGIN LICENSE BLOCK *****
   3  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
   4  *
   5  * The contents of this file are subject to the Mozilla Public License Version
   6  * 1.1 (the "License"); you may not use this file except in compliance with
   7  * the License. You may obtain a copy of the License at
   8  * http://www.mozilla.org/MPL/
   9  *
  10  * Software distributed under the License is distributed on an "AS IS" basis,
  11  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  12  * for the specific language governing rights and limitations under the
  13  * License.
  14  *
  15  * The Original Code is mozilla.org code.
  16  *
  17  * The Initial Developer of the Original Code is
  18  * Mozilla Foundation.
  19  * Portions created by the Initial Developer are Copyright (C) 2007
  20  * the Initial Developer. All Rights Reserved.
  21  *
  22  * Contributor(s):
  23  *   Alexander Surkov <surkov.alexander@gmail.com> (original author)
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of
  26  * either of the GNU General Public License Version 2 or later (the "GPL"),
  27  * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  28  * in which case the provisions of the GPL or the LGPL are applicable instead
  29  * of those above. If you wish to allow use of your version of this file only
  30  * under the terms of either the GPL or the LGPL, and not to allow others to
  31  * use your version of this file under the terms of the MPL, indicate your
  32  * decision by deleting the provisions above and replace them with the notice
  33  * and other provisions required by the GPL or the LGPL. If you do not delete
  34  * the provisions above, a recipient may use your version of this file under
  35  * the terms of any one of the MPL, the GPL or the LGPL.
  36  *
  37  * ***** END LICENSE BLOCK ***** */
  38
  39 #ifndef nsCoreUtils_h_
  40 #define nsCoreUtils_h_
  41
  42 #include "nsAccessibilityAtoms.h"
  43
  44 #include "nsIDOMNode.h"
  45 #include "nsIContent.h"
  46 #include "nsIFrame.h"
  47 #include "nsIDocShellTreeItem.h"
  48 #include "nsPoint.h"
  49
  50 class nsCoreUtils
  51 {
  52 public:
  53   /**
  54    * Return true if the given node has registered event listener of the given
  55    * type.
  56    */
  57   static PRBool HasListener(nsIContent *aContent, const nsAString& aEventType);
  58
  59   /**
  60    * Send mouse events to the given element.
  61    *
  62    * @param aEventType  an event type (see nsGUIEvent.h for constants)
  63    * @param aPresShell  the presshell for the given element
  64    * @param aContent    the element element
  65    */
  66   static PRBool DispatchMouseEvent(PRUint32 aEventType,
  67                                    nsIPresShell *aPresShell,
  68                                    nsIContent *aContent);
  69
  70   /**
  71    * Return an accesskey registered on the given element by
  72    * nsIEventStateManager or 0 if there is no registered accesskey.
  73    *
  74    * @param aContent - the given element.
  75    */
  76   static PRUint32 GetAccessKeyFor(nsIContent *aContent);
  77
  78   /**
  79    * Return DOM element related with the given node, i.e.
  80    * a) itself if it is DOM element
  81    * b) parent element if it is text node
  82    * c) body element if it is HTML document node
  83    * d) document element if it is document node.
  84    *
  85    * @param aNode  [in] the given DOM node
  86    */
  87   static already_AddRefed<nsIDOMElement> GetDOMElementFor(nsIDOMNode *aNode);
  88
  89   /**
  90    * Return the nsIContent* to check for ARIA attributes on -- this may not
  91    * always be the DOM node for the accessible. Specifically, for doc
  92    * accessibles, it is not the document node, but either the root element or
  93    * <body> in HTML. Similar with GetDOMElementFor() method.
  94    *
  95    * @param aDOMNode  DOM node for the accessible that may be affected by ARIA
  96    * @return          the nsIContent which may have ARIA markup
  97    */
  98   static nsIContent *GetRoleContent(nsIDOMNode *aDOMNode);
  99
 100   /**
 101    * Is the first passed in node an ancestor of the second?
 102    * Note: A node is not considered to be the ancestor of itself.
 103    * @param aPossibleAncestorNode -- node to test for ancestor-ness of aPossibleDescendantNode
 104    * @param aPossibleDescendantNode -- node to test for descendant-ness of aPossibleAncestorNode
 105    * @return PR_TRUE if aPossibleAncestorNode is an ancestor of aPossibleDescendantNode
 106    */
 107    static PRBool IsAncestorOf(nsIDOMNode *aPossibleAncestorNode,
 108                               nsIDOMNode *aPossibleDescendantNode);
 109
 110   /**
 111    * Are the first node and the second siblings?
 112    * @return PR_TRUE if aDOMNode1 and aDOMNode2 have same parent
 113    */
 114    static PRBool AreSiblings(nsIDOMNode *aDOMNode1,
 115                              nsIDOMNode *aDOMNode2);
 116
 117   /**
 118    * Helper method to scroll range into view, used for implementation of
 119    * nsIAccessibleText::scrollSubstringTo().
 120    *
 121    * @param aFrame        the frame for accessible the range belongs to.
 122    * @param aStartNode    start node of a range
 123    * @param aStartOffset  an offset inside the start node
 124    * @param aEndNode      end node of a range
 125    * @param aEndOffset    an offset inside the end node
 126    * @param aScrollType   the place a range should be scrolled to
 127    */
 128   static nsresult ScrollSubstringTo(nsIFrame *aFrame,
 129                                     nsIDOMNode *aStartNode, PRInt32 aStartIndex,
 130                                     nsIDOMNode *aEndNode, PRInt32 aEndIndex,
 131                                     PRUint32 aScrollType);
 132
 133   /** Helper method to scroll range into view, used for implementation of
 134    * nsIAccessibleText::scrollSubstringTo[Point]().
 135    *
 136    * @param aFrame        the frame for accessible the range belongs to.
 137    * @param aStartNode    start node of a range
 138    * @param aStartOffset  an offset inside the start node
 139    * @param aEndNode      end node of a range
 140    * @param aEndOffset    an offset inside the end node
 141    * @param aVPercent     how to align vertically, specified in percents
 142    * @param aHPercent     how to align horizontally, specified in percents
 143    */
 144   static nsresult ScrollSubstringTo(nsIFrame *aFrame,
 145                                     nsIDOMNode *aStartNode, PRInt32 aStartIndex,
 146                                     nsIDOMNode *aEndNode, PRInt32 aEndIndex,
 147                                     PRInt16 aVPercent, PRInt16 aHPercent);
 148
 149   /**
 150    * Scrolls the given frame to the point, used for implememntation of
 151    * nsIAccessNode::scrollToPoint and nsIAccessibleText::scrollSubstringToPoint.
 152    *
 153    * @param aScrollableFrame  the scrollable frame
 154    * @param aFrame            the frame to scroll
 155    * @param aPoint            the point scroll to
 156    */
 157   static void ScrollFrameToPoint(nsIFrame *aScrollableFrame,
 158                                  nsIFrame *aFrame, const nsIntPoint& aPoint);
 159
 160   /**
 161    * Converts scroll type constant defined in nsIAccessibleScrollType to
 162    * vertical and horizontal percents.
 163    */
 164   static void ConvertScrollTypeToPercents(PRUint32 aScrollType,
 165                                           PRInt16 *aVPercent,
 166                                           PRInt16 *aHPercent);
 167
 168   /**
 169    * Returns coordinates relative screen for the top level window.
 170    *
 171    * @param aNode  the DOM node hosted in the window.
 172    */
 173   static nsIntPoint GetScreenCoordsForWindow(nsIDOMNode *aNode);
 174
 175   /**
 176    * Return document shell tree item for the given DOM node.
 177    */
 178   static already_AddRefed<nsIDocShellTreeItem>
 179     GetDocShellTreeItemFor(nsIDOMNode *aNode);
 180
 181   /**
 182    * Retrun frame for the given DOM element.
 183    */
 184   static nsIFrame* GetFrameFor(nsIDOMElement *aElm);
 185
 186   /**
 187    * Retrun true if the type of given frame equals to the given frame type.
 188    *
 189    * @param aFrame  the frame
 190    * @param aAtom   the frame type
 191    */
 192   static PRBool IsCorrectFrameType(nsIFrame* aFrame, nsIAtom* aAtom);
 193
 194   /**
 195    * Return presShell for the document containing the given DOM node.
 196    */
 197   static already_AddRefed<nsIPresShell> GetPresShellFor(nsIDOMNode *aNode);
 198
 199   /**
 200    * Return document node for the given document shell tree item.
 201    */
 202   static already_AddRefed<nsIDOMNode>
 203     GetDOMNodeForContainer(nsIDocShellTreeItem *aContainer);
 204
 205   /**
 206    * Get the ID for an element, in some types of XML this may not be the ID attribute
 207    * @param aContent  Node to get the ID for
 208    * @param aID       Where to put ID string
 209    * @return          PR_TRUE if there is an ID set for this node
 210    */
 211   static PRBool GetID(nsIContent *aContent, nsAString& aID);
 212
 213   /**
 214    * Check if the given element is XLink.
 215    *
 216    * @param aContent  the given element
 217    * @return          PR_TRUE if the given element is XLink
 218    */
 219   static PRBool IsXLink(nsIContent *aContent);
 220
 221   /**
 222    * Returns language for the given node.
 223    *
 224    * @param aContent     [in] the given node
 225    * @param aRootContent [in] container of the given node
 226    * @param aLanguage    [out] language
 227    */
 228   static void GetLanguageFor(nsIContent *aContent, nsIContent *aRootContent,
 229                              nsAString& aLanguage);
 230
 231   /**
 232    * Return computed styles declaration for the given node.
 233    */
 234   static void GetComputedStyleDeclaration(const nsAString& aPseudoElt,
 235                                           nsIDOMNode *aNode,
 236                                           nsIDOMCSSStyleDeclaration **aCssDecl);
 237
 238   /**
 239    * Search element in neighborhood of the given element by tag name and
 240    * attribute value that equals to ID attribute of the given element.
 241    * ID attribute can be either 'id' attribute or 'anonid' if the element is
 242    * anonymous.
 243    * The first matched content will be returned.
 244    *
 245    * @param aForNode - the given element the search is performed for
 246    * @param aRelationAttrs - an array of attributes, element is attribute name of searched element, ignored if aAriaProperty passed in
 247    * @param aAttrNum - how many attributes in aRelationAttrs
 248    * @param aTagName - tag name of searched element, or nsnull for any -- ignored if aAriaProperty passed in
 249    * @param aAncestorLevelsToSearch - points how is the neighborhood of the
 250    *                                  given element big.
 251    */
 252   static nsIContent *FindNeighbourPointingToNode(nsIContent *aForNode,
 253                                                  nsIAtom **aRelationAttrs,
 254                                                  PRUint32 aAttrNum,
 255                                                  nsIAtom *aTagName = nsnull,
 256                                                  PRUint32 aAncestorLevelsToSearch = 5);
 257
 258   /**
 259    * Overloaded version of FindNeighbourPointingToNode to accept only one
 260    * relation attribute.
 261    */
 262   static nsIContent *FindNeighbourPointingToNode(nsIContent *aForNode,
 263                                                  nsIAtom *aRelationAttr,
 264                                                  nsIAtom *aTagName = nsnull,
 265                                                  PRUint32 aAncestorLevelsToSearch = 5);
 266
 267   /**
 268    * Search for element that satisfies the requirements in subtree of the given
 269    * element. The requirements are tag name, attribute name and value of
 270    * attribute.
 271    * The first matched content will be returned.
 272    *
 273    * @param aId - value of searched attribute
 274    * @param aLookContent - element that search is performed inside
 275    * @param aRelationAttrs - an array of searched attributes
 276    * @param aAttrNum - how many attributes in aRelationAttrs
 277    * @param                 if both aAriaProperty and aRelationAttrs are null, then any element with aTagType will do
 278    * @param aExcludeContent - element that is skiped for search
 279    * @param aTagType - tag name of searched element, by default it is 'label' --
 280    *                   ignored if aAriaProperty passed in
 281    */
 282   static nsIContent *FindDescendantPointingToID(const nsString *aId,
 283                                                 nsIContent *aLookContent,
 284                                                 nsIAtom **aRelationAttrs,
 285                                                 PRUint32 aAttrNum = 1,
 286                                                 nsIContent *aExcludeContent = nsnull,
 287                                                 nsIAtom *aTagType = nsAccessibilityAtoms::label);
 288
 289   /**
 290    * Overloaded version of FindDescendantPointingToID to accept only one
 291    * relation attribute.
 292    */
 293   static nsIContent *FindDescendantPointingToID(const nsString *aId,
 294                                                 nsIContent *aLookContent,
 295                                                 nsIAtom *aRelationAttr,
 296                                                 nsIContent *aExcludeContent = nsnull,
 297                                                 nsIAtom *aTagType = nsAccessibilityAtoms::label);
 298
 299   // Helper for FindDescendantPointingToID(), same args
 300   static nsIContent *FindDescendantPointingToIDImpl(nsCString& aIdWithSpaces,
 301                                                     nsIContent *aLookContent,
 302                                                     nsIAtom **aRelationAttrs,
 303                                                     PRUint32 aAttrNum = 1,
 304                                                     nsIContent *aExcludeContent = nsnull,
 305                                                     nsIAtom *aTagType = nsAccessibilityAtoms::label);
 306
 307   /**
 308    * Return the label element for the given DOM element.
 309    */
 310   static nsIContent *GetLabelContent(nsIContent *aForNode);
 311
 312   /**
 313    * Return the HTML label element for the given HTML element.
 314    */
 315   static nsIContent *GetHTMLLabelContent(nsIContent *aForNode);
 316
 317
 318 };
 319
 320 #endif
 321