author Fernando Herrera <>
Thu, 03 Feb 2011 18:59:14 +0100
changeset 61866 6d9ac157fc84be6c489ecfcdc6a4dfb5fc3b8b0d
parent 61467 523d042cda9724664e511aa6dc1a4e95dbbfa163
permissions -rw-r--r--
Bug 630841 - Crash in nsHyperTextAccessible::GetText(), r=surkov, a=blocking

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 * The Original Code is code.
 * The Initial Developers of the Original Code are
 * Sun Microsystems and IBM Corporation
 * Portions created by the Initial Developer are Copyright (C) 2006
 * the Initial Developer. All Rights Reserved.
 * Contributor(s):
 *   Ginn Chen (
 *   Aaron Leventhal (
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
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#ifndef _nsHyperTextAccessible_H_
#define _nsHyperTextAccessible_H_

#include "nsIAccessibleText.h"
#include "nsIAccessibleHyperText.h"
#include "nsIAccessibleEditableText.h"

#include "AccCollector.h"
#include "nsAccessibleWrap.h"
#include "nsTextAttrs.h"

#include "nsFrameSelection.h"
#include "nsISelectionController.h"

enum EGetTextType { eGetBefore=-1, eGetAt=0, eGetAfter=1 };

// This character marks where in the text returned via nsIAccessibleText(),
// that embedded object characters exist
const PRUnichar kEmbeddedObjectChar = 0xfffc;
const PRUnichar kImaginaryEmbeddedObjectChar = ' ';
const PRUnichar kForcedNewLineChar = '\n';

#define NS_HYPERTEXTACCESSIBLE_IMPL_CID                 \
{  /* 245f3bc9-224f-4839-a92e-95239705f30b */           \
  0x245f3bc9,                                           \
  0x224f,                                               \
  0x4839,                                               \
  { 0xa9, 0x2e, 0x95, 0x23, 0x97, 0x05, 0xf3, 0x0b }    \

  * Special Accessible that knows how contain both text and embedded objects
class nsHyperTextAccessible : public nsAccessibleWrap,
                              public nsIAccessibleText,
                              public nsIAccessibleHyperText,
                              public nsIAccessibleEditableText
  nsHyperTextAccessible(nsIContent *aContent, nsIWeakReference *aShell);

  // nsAccessible
  virtual PRInt32 GetLevelInternal();
  virtual nsresult GetAttributesInternal(nsIPersistentProperties *aAttributes);
  virtual PRUint32 NativeRole();
  virtual nsresult GetStateInternal(PRUint32 *aState, PRUint32 *aExtraState);
  virtual PRBool RemoveChild(nsAccessible *aAccessible);

  virtual void InvalidateChildren();

  // nsHyperTextAccessible (static helper method)

  // Convert content offset to rendered text offset  
  static nsresult ContentToRenderedOffset(nsIFrame *aFrame, PRInt32 aContentOffset,
                                          PRUint32 *aRenderedOffset);
  // Convert rendered text offset to content offset
  static nsresult RenderedToContentOffset(nsIFrame *aFrame, PRUint32 aRenderedOffset,
                                          PRInt32 *aContentOffset);

  // HyperLinkAccessible

   * Return link count within this hypertext accessible.
  inline PRUint32 GetLinkCount()
    return GetEmbeddedChildCount();

   * Return link accessible at the given index.
  inline nsAccessible* GetLinkAt(PRUint32 aIndex)
    return GetEmbeddedChildAt(aIndex);

   * Return index for the given link accessible.
  inline PRInt32 GetLinkIndex(nsAccessible* aLink)
    return GetIndexOfEmbeddedChild(aLink);

   * Return link accessible at the given text offset.
  inline PRInt32 GetLinkIndexAtOffset(PRUint32 aOffset)
    nsAccessible* child = GetChildAtOffset(aOffset);
    return child ? GetLinkIndex(child) : -1;

  // nsHyperTextAccessible: DOM point to text offset conversions.

    * Turn a DOM Node and offset into a character offset into this hypertext.
    * Will look for closest match when the DOM node does not have an accessible
    * object associated with it. Will return an offset for the end of
    * the string if the node is not found.
    * @param aNode - the node to look for
    * @param aNodeOffset - the offset to look for
    *                      if -1 just look directly for the node
    *                      if >=0 and aNode is text, this represents a char offset
    *                      if >=0 and aNode is not text, this represents a child node offset
    * @param aResultOffset - the character offset into the current
    *                        nsHyperTextAccessible
    * @param aIsEndOffset - if PR_TRUE, then then this offset is not inclusive. The character
    *                       indicated by the offset returned is at [offset - 1]. This means
    *                       if the passed-in offset is really in a descendant, then the offset returned
    *                       will come just after the relevant embedded object characer.
    *                       If PR_FALSE, then the offset is inclusive. The character indicated
    *                       by the offset returned is at [offset]. If the passed-in offset in inside a
    *                       descendant, then the returned offset will be on the relevant embedded object char.
    * @return               the accessible child which contained the offset, if
    *                       it is within the current nsHyperTextAccessible,
    *                       otherwise nsnull
  nsAccessible *DOMPointToHypertextOffset(nsINode *aNode,
                                          PRInt32 aNodeOffset,
                                          PRInt32 *aHypertextOffset,
                                          PRBool aIsEndOffset = PR_FALSE);

   * Turn a hypertext offsets into DOM point.
   * @param  aHTOffset  [in] the given start hypertext offset
   * @param  aNode      [out] start node
   * @param  aOffset    [out] offset inside the start node
  nsresult HypertextOffsetToDOMPoint(PRInt32 aHTOffset,
                                     nsIDOMNode **aNode,
                                     PRInt32 *aOffset);

   * Turn a start and end hypertext offsets into DOM range.
   * @param  aStartHTOffset  [in] the given start hypertext offset
   * @param  aEndHTOffset    [in] the given end hypertext offset
   * @param  aStartNode      [out] start node of the range
   * @param  aStartOffset    [out] start offset of the range
   * @param  aEndNode        [out] end node of the range
   * @param  aEndOffset      [out] end offset of the range
  nsresult HypertextOffsetsToDOMRange(PRInt32 aStartHTOffset,
                                      PRInt32 aEndHTOffset,
                                      nsIDOMNode **aStartNode,
                                      PRInt32 *aStartOffset,
                                      nsIDOMNode **aEndNode,
                                      PRInt32 *aEndOffset);

  // TextAccessible

   * Return character count within the hypertext accessible.
  inline PRUint32 CharacterCount()
    return GetChildOffset(GetChildCount());

   * Return text offset of the given child accessible within hypertext
   * accessible.
   * @param  aChild           [in] accessible child to get text offset for
   * @param  aInvalidateAfter [in, optional] indicates whether invalidate
   *                           cached offsets for next siblings of the child
  PRInt32 GetChildOffset(nsAccessible* aChild,
                         PRBool aInvalidateAfter = PR_FALSE)
    PRInt32 index = GetIndexOf(aChild);
    return index == -1 ? -1 : GetChildOffset(index, aInvalidateAfter);

   * Return text offset for the child accessible index.
  PRInt32 GetChildOffset(PRUint32 aChildIndex,
                         PRBool aInvalidateAfter = PR_FALSE);

   * Return child accessible at the given text offset.
   * @param  aOffset  [in] the given text offset
  PRInt32 GetChildIndexAtOffset(PRUint32 aOffset);

   * Return child accessible at the given text offset.
   * @param  aOffset  [in] the given text offset
  nsAccessible* GetChildAtOffset(PRUint32 aOffset)
    return GetChildAt(GetChildIndexAtOffset(aOffset));

  // nsHyperTextAccessible

   * This does the work for nsIAccessibleText::GetText[At|Before|After]Offset
   * @param aType, eGetBefore, eGetAt, eGetAfter
   * @param aBoundaryType, char/word-start/word-end/line-start/line-end/paragraph/attribute
   * @param aOffset, offset into the hypertext to start from
   * @param *aStartOffset, the resulting start offset for the returned substring
   * @param *aEndOffset, the resulting end offset for the returned substring
   * @param aText, the resulting substring
   * @return success/failure code
  nsresult GetTextHelper(EGetTextType aType, nsAccessibleTextBoundary aBoundaryType,
                         PRInt32 aOffset, PRInt32 *aStartOffset, PRInt32 *aEndOffset,
                         nsAString & aText);

    * Used by GetTextHelper() to move backward/forward from a given point
    * by word/line/etc.
    * @param  aPresShell       the current presshell we're moving in
    * @param  aFromFrame       the starting frame we're moving from
    * @param  aFromOffset      the starting offset we're moving from
    * @param  aFromAccessible  the starting accessible we're moving from
    * @param  aAmount          how much are we moving (word/line/etc.) ?
    * @param  aDirection       forward or backward?
    * @param  aNeedsStart      for word and line cases, are we basing this on
    *                          the start or end?
    * @return                  the resulting offset into this hypertext
  PRInt32 GetRelativeOffset(nsIPresShell *aPresShell, nsIFrame *aFromFrame,
                            PRInt32 aFromOffset, nsAccessible *aFromAccessible,
                            nsSelectionAmount aAmount, nsDirection aDirection,
                            PRBool aNeedsStart);

    * Provides information for substring that is defined by the given start
    * and end offsets for this hyper text.
    * @param  aStartOffset  [inout] the start offset into the hyper text. This
    *                       is also an out parameter used to return the offset
    *                       into the start frame's rendered text content
    *                       (start frame is the @return)
    * @param  aEndOffset    [inout] the end offset into the hyper text. This is
    *                       also an out parameter used to return
    *                       the offset into the end frame's rendered
    *                       text content.
    * @param  aText         [out, optional] return the substring's text
    * @param  aEndFrame     [out, optional] return the end frame for this
    *                       substring
    * @param  aBoundsRect   [out, optional] return the bounds rectangle for this
    *                       substring
    * @param  aStartAcc     [out, optional] return the start accessible for this
    *                       substring
    * @param  aEndAcc       [out, optional] return the end accessible for this
    *                       substring
    * @return               the start frame for this substring
  nsIFrame* GetPosAndText(PRInt32& aStartOffset, PRInt32& aEndOffset,
                          nsAString *aText = nsnull,
                          nsIFrame **aEndFrame = nsnull,
                          nsIntRect *aBoundsRect = nsnull,
                          nsAccessible **aStartAcc = nsnull,
                          nsAccessible **aEndAcc = nsnull);

  nsIntRect GetBoundsForString(nsIFrame *aFrame, PRUint32 aStartRenderedOffset, PRUint32 aEndRenderedOffset);

  // Selection helpers

   * Get the relevant selection interfaces and ranges for the current hyper
   * text.
   * @param aType    [in] the selection type
   * @param aSelCon  [out, optional] the selection controller for the current
   *                 hyper text
   * @param aDomSel  [out, optional] the selection interface for the current
   *                 hyper text
   * @param aRanges  [out, optional] the selected ranges within the current
   *                 subtree
  nsresult GetSelections(PRInt16 aType,
                         nsISelectionController **aSelCon,
                         nsISelection **aDomSel = nsnull,
                         nsCOMArray<nsIDOMRange>* aRanges = nsnull);

  nsresult SetSelectionRange(PRInt32 aStartPos, PRInt32 aEndPos);

   * Provide the line number for the caret, relative to the
   * current DOM node.
   * @return 1-based index for the line number with the caret
  PRInt32 GetCaretLineNumber();

  // Helpers
  nsresult GetDOMPointByFrameOffset(nsIFrame *aFrame, PRInt32 aOffset,
                                    nsIAccessible *aAccessible,
                                    nsIDOMNode **aNode, PRInt32 *aNodeOffset);

   * Return hyper text offset for the specified bound of the given DOM range.
   * If the bound is outside of the hyper text then offset value is either
   * 0 or number of characters of hyper text, it depends on type of requested
   * offset. The method is a wrapper for DOMPointToHypertextOffset.
   * @param aRange          [in] the given range
   * @param aIsStartBound   [in] specifies whether the required range bound is
   *                        start bound
   * @param aIsStartOffset  [in] the offset type, used when the range bound is
   *                        outside of hyper text
   * @param aHTOffset       [out] the result offset
  nsresult DOMRangeBoundToHypertextOffset(nsIDOMRange *aRange,
                                          PRBool aIsStartBound,
                                          PRBool aIsStartOffset,
                                          PRInt32 *aHTOffset);

   * Set 'misspelled' text attribute and return range offsets where the
   * attibute is stretched. If the text is not misspelled at the given offset
   * then we expose only range offsets where text is not misspelled. The method
   * is used by GetTextAttributes() method.
   * @param aIncludeDefAttrs  [in] points whether text attributes having default
   *                          values of attributes should be included
   * @param aSourceNode       [in] the node we start to traverse from
   * @param aStartOffset      [in, out] the start offset
   * @param aEndOffset        [in, out] the end offset
   * @param aAttributes       [out, optional] result attributes
  nsresult GetSpellTextAttribute(nsIDOMNode *aNode, PRInt32 aNodeOffset,
                                 PRInt32 *aStartOffset,
                                 PRInt32 *aEndOffset,
                                 nsIPersistentProperties *aAttributes);

   * End text offsets array.
  nsTArray<PRUint32> mOffsets;


// nsAccessible downcasting method

inline nsHyperTextAccessible*
  return mFlags & eHyperTextAccessible ?
    static_cast<nsHyperTextAccessible*>(this) : nsnull;

#endif  // _nsHyperTextAccessible_H_