Backed out changeset d4c9a0776667 (deCOM nsILineEnumerator) due to regression from it or bug 461212

accessible/src/html/nsHyperTextAccessible.cpp

@@ -1685,7 +1685,7 @@ PRInt32 nsHyperTextAccessible::GetCaretLineNumber()
   NS_ENSURE_TRUE(caretFrame, -1);
 
   PRInt32 lineNumber = 1;
-  nsAutoLineIterator lineIterForCaret;
+  nsCOMPtr<nsILineIterator> lineIterForCaret;
   nsCOMPtr<nsIContent> hyperTextContent = do_QueryInterface(mDOMNode);
   while (caretFrame) {
     if (hyperTextContent == caretFrame->GetContent()) {
@@ -1698,10 +1698,11 @@ PRInt32 nsHyperTextAccessible::GetCaretLineNumber()
     // Add lines for the sibling frames before the caret
     nsIFrame *sibling = parentFrame->GetFirstChild(nsnull);
     while (sibling && sibling != caretFrame) {
-      nsAutoLineIterator lineIterForSibling = sibling->GetLineIterator();
+      nsCOMPtr<nsILineIterator> lineIterForSibling = do_QueryInterface(sibling);
       if (lineIterForSibling) {
+        PRInt32 addLines;
         // For the frames before that grab all the lines
-        PRInt32 addLines = lineIterForSibling->GetNumLines();
+        lineIterForSibling->GetNumLines(&addLines);
         lineNumber += addLines;
       }
       sibling = sibling->GetNextSibling();
@@ -1709,10 +1710,11 @@ PRInt32 nsHyperTextAccessible::GetCaretLineNumber()
 
     // Get the line number relative to the container with lines
     if (!lineIterForCaret) {   // Add the caret line just once
-      lineIterForCaret = parentFrame->GetLineIterator();
+      lineIterForCaret = do_QueryInterface(parentFrame);
       if (lineIterForCaret) {
         // Ancestor of caret
-        PRInt32 addLines = lineIterForCaret->FindLineContaining(caretFrame);
+        PRInt32 addLines;
+        lineIterForCaret->FindLineContaining(caretFrame, &addLines);
         lineNumber += addLines;
       }
     }

layout/base/nsPresShell.cpp

@@ -3801,9 +3801,11 @@ UnionRectForClosestScrolledView(nsIFrame* aFrame,
         f &&
         frameType == nsGkAtoms::blockFrame) {
       // find the line containing aFrame and increase the top of |offset|.
-      nsAutoLineIterator lines = f->GetLineIterator();
+      nsCOMPtr<nsILineIterator> lines(do_QueryInterface(f));
+
       if (lines) {
-        PRInt32 index = lines->FindLineContaining(prevFrame);
+        PRInt32 index = -1;
+        lines->FindLineContaining(prevFrame, &index);
         if (index >= 0) {
           nsIFrame *trash1;
           PRInt32 trash2;

layout/generic/nsBlockFrame.cpp

@@ -315,22 +315,6 @@ nsBlockFrame::Destroy()
   nsBlockFrameSuper::Destroy();
 }
 
-/* virtual */ nsILineIterator*
-nsBlockFrame::GetLineIterator()
-{
-  nsLineIterator* it = new nsLineIterator;
-  if (!it)
-    return nsnull;
-
-  const nsStyleVisibility* visibility = GetStyleVisibility();
-  nsresult rv = it->Init(mLines, visibility->mDirection == NS_STYLE_DIRECTION_RTL);
-  if (NS_FAILED(rv)) {
-    delete it;
-    return nsnull;
-  }
-  return it;
-}
-
 NS_IMETHODIMP
 nsBlockFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
 {
@@ -340,6 +324,26 @@ nsBlockFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
     *aInstancePtr = static_cast<void*>(static_cast<nsBlockFrame*>(this));
     return NS_OK;
   }
+  if (aIID.Equals(NS_GET_IID(nsILineIterator)) ||
+      aIID.Equals(NS_GET_IID(nsILineIteratorNavigator))) {
+    nsLineIterator* it = new nsLineIterator;
+    if (!it) {
+      *aInstancePtr = nsnull;
+      return NS_ERROR_OUT_OF_MEMORY;
+    }
+    NS_ADDREF(it); // reference passed to caller
+    const nsStyleVisibility* visibility = GetStyleVisibility();
+    nsresult rv = it->Init(mLines,
+                           visibility->mDirection == NS_STYLE_DIRECTION_RTL);
+    if (NS_FAILED(rv)) {
+      *aInstancePtr = nsnull;
+      NS_RELEASE(it);
+      return rv;
+    }
+    *aInstancePtr = static_cast<nsILineIteratorNavigator*>(it);
+    return NS_OK;
+  }
+
   return nsBlockFrameSuper::QueryInterface(aIID, aInstancePtr);
 }
 

layout/generic/nsBlockFrame.h

@@ -74,6 +74,7 @@ class nsBlockInFlowLineIterator;
 class nsBulletFrame;
 class nsLineBox;
 class nsFirstLineFrame;
+class nsILineIterator;
 class nsIntervalSet;
 /**
  * Child list name indices
@@ -597,8 +598,6 @@ protected:
 
   //----------------------------------------
 
-  virtual nsILineIterator* GetLineIterator();
-
 public:
   nsLineList* GetOverflowLines() const;
 protected:

layout/generic/nsFrame.cpp

@@ -4558,8 +4558,6 @@ nsFrame::GetNextPrevLineFromeBlockFrame(nsPresContext* aPresContext,
                                         PRInt8 aOutSideLimit
                                         )
 {
-  nsresult result;
-
   //magic numbers aLineStart will be -1 for end of block 0 will be start of block
   if (!aBlockFrame || !aPos)
     return NS_ERROR_NULL_POINTER;
@@ -4568,11 +4566,14 @@ nsFrame::GetNextPrevLineFromeBlockFrame(nsPresContext* aPresContext,
   aPos->mResultContent = nsnull;
   aPos->mAttachForward = (aPos->mDirection == eDirNext);
 
-  nsAutoLineIterator it = aBlockFrame->GetLineIterator();
+   nsresult result;
-  if (!it)
+  nsCOMPtr<nsILineIteratorNavigator> it; 
-    return NS_ERROR_FAILURE;
+  result = aBlockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
+  if (NS_FAILED(result) || !it)
+    return result;
   PRInt32 searchingLine = aLineStart;
-  PRInt32 countLines = it->GetNumLines();
+  PRInt32 countLines;
+  result = it->GetNumLines(&countLines);
   if (aOutSideLimit > 0) //start at end
     searchingLine = countLines;
   else if (aOutSideLimit <0)//start at beginning
@@ -4640,9 +4641,10 @@ nsFrame::GetNextPrevLineFromeBlockFrame(nsPresContext* aPresContext,
 
     if (NS_SUCCEEDED(result) && resultFrame)
     {
+      nsCOMPtr<nsILineIteratorNavigator> newIt; 
       //check to see if this is ANOTHER blockframe inside the other one if so then call into its lines
-      nsAutoLineIterator newIt = resultFrame->GetLineIterator();
+      result = resultFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(newIt));
-      if (newIt)
+      if (NS_SUCCEEDED(result) && newIt)
       {
         aPos->mResultFrame = resultFrame;
         return NS_OK;
@@ -5085,16 +5087,15 @@ nsIFrame::PeekOffset(nsPeekOffsetStruct* aPos)
     }
     case eSelectLine :
     {
-      nsAutoLineIterator iter;
+      nsCOMPtr<nsILineIteratorNavigator> iter; 
       nsIFrame *blockFrame = this;
 
       while (NS_FAILED(result)){
         PRInt32 thisLine = nsFrame::GetLineNumber(blockFrame, aPos->mScrollViewStop, &blockFrame);
         if (thisLine < 0) 
           return  NS_ERROR_FAILURE;
-        iter = blockFrame->GetLineIterator();
+        result = blockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(iter));
-        NS_ASSERTION(iter, "GetLineNumber() succeeded but no block frame?");
+        NS_ASSERTION(NS_SUCCEEDED(result) && iter, "GetLineNumber() succeeded but no block frame?");
-        result = NS_OK;
 
         int edgeCase = 0;//no edge case. this should look at thisLine
         
@@ -5138,23 +5139,20 @@ nsIFrame::PeekOffset(nsPeekOffsetStruct* aPos)
               //got the table frame now
               while(frame) //ok time to drill down to find iterator
               {
-                iter = frame->GetLineIterator();
+                result = frame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),
-                if (iter)
+                                                          getter_AddRefs(iter));
+                if (NS_SUCCEEDED(result))
                 {
                   aPos->mResultFrame = frame;
                   searchTableBool = PR_TRUE;
-                  result = NS_OK;
                   break; //while(frame)
                 }
-                result = NS_ERROR_FAILURE;
                 frame = frame->GetFirstChild(nsnull);
               }
             }
-
+            if (!searchTableBool)
-            if (!searchTableBool) {
+              result = aPos->mResultFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),
-              iter = aPos->mResultFrame->GetLineIterator();
+                                                        getter_AddRefs(iter));
-              result = iter ? NS_OK : NS_ERROR_FAILURE;
-            }
             if (NS_SUCCEEDED(result) && iter)//we've struck another block element!
             {
               doneLooping = PR_FALSE;
@@ -5184,13 +5182,14 @@ nsIFrame::PeekOffset(nsPeekOffsetStruct* aPos)
     case eSelectBeginLine:
     case eSelectEndLine:
     {
+      nsCOMPtr<nsILineIteratorNavigator> it;
       // Adjusted so that the caret can't get confused when content changes
       nsIFrame* blockFrame = AdjustFrameForSelectionStyles(this);
       PRInt32 thisLine = nsFrame::GetLineNumber(blockFrame, aPos->mScrollViewStop, &blockFrame);
       if (thisLine < 0)
         return NS_ERROR_FAILURE;
-      nsAutoLineIterator it = blockFrame->GetLineIterator();
+      result = blockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
-      NS_ASSERTION(it, "GetLineNumber() succeeded but no block frame?");
+      NS_ASSERTION(NS_SUCCEEDED(result) && it, "GetLineNumber() succeeded but no block frame?");
 
       PRInt32 lineFrameCount;
       nsIFrame *firstFrame;
@@ -5201,7 +5200,8 @@ nsIFrame::PeekOffset(nsPeekOffsetStruct* aPos)
       
 #ifdef IBMBIDI
       if (aPos->mVisual && PresContext()->BidiEnabled()) {
-        PRBool lineIsRTL = it->GetDirection();
+        PRBool lineIsRTL;
+        it->GetDirection(&lineIsRTL);
         PRBool isReordered;
         nsIFrame *lastFrame;
         result = it->CheckLineOrder(thisLine, &isReordered, &firstFrame, &lastFrame);
@@ -5357,7 +5357,7 @@ nsFrame::GetLineNumber(nsIFrame *aFrame, PRBool aLockScroll, nsIFrame** aContain
   nsIFrame *blockFrame = aFrame;
   nsIFrame *thisBlock;
   PRInt32   thisLine;
-  nsAutoLineIterator it;
+  nsCOMPtr<nsILineIteratorNavigator> it; 
   nsresult result = NS_ERROR_FAILURE;
   while (NS_FAILED(result) && blockFrame)
   {
@@ -5378,7 +5378,7 @@ nsFrame::GetLineNumber(nsIFrame *aFrame, PRBool aLockScroll, nsIFrame** aContain
     if (blockFrame) {
       if (aLockScroll && blockFrame->GetType() == nsGkAtoms::scrollFrame)
         return -1;
-      it = blockFrame->GetLineIterator();
+      result = blockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
     }
   }
   if (!blockFrame || !it)
@@ -5386,16 +5386,17 @@ nsFrame::GetLineNumber(nsIFrame *aFrame, PRBool aLockScroll, nsIFrame** aContain
 
   if (aContainingBlock)
     *aContainingBlock = blockFrame;
-  return it->FindLineContaining(thisBlock);
+  result = it->FindLineContaining(thisBlock, &thisLine);
+  if (NS_FAILED(result))
+    return -1;
+  return thisLine;
 }
 
 nsresult
 nsIFrame::GetFrameFromDirection(nsDirection aDirection, PRBool aVisual,
                                 PRBool aJumpLines, PRBool aScrollViewStop, 
                                 nsIFrame** aOutFrame, PRInt32* aOutOffset, PRBool* aOutJumpedLine)
-{
+{  
-  nsresult result;
-
   if (!aOutFrame || !aOutOffset || !aOutJumpedLine)
     return NS_ERROR_NULL_POINTER;
   
@@ -5409,20 +5410,21 @@ nsIFrame::GetFrameFromDirection(nsDirection aDirection, PRBool aVisual,
   nsIFrame *traversedFrame = this;
   while (!selectable) {
     nsIFrame *blockFrame;
+    nsCOMPtr<nsILineIteratorNavigator> it; 
     
     PRInt32 thisLine = nsFrame::GetLineNumber(traversedFrame, aScrollViewStop, &blockFrame);
     if (thisLine < 0)
       return NS_ERROR_FAILURE;
-
+    nsresult result = blockFrame->QueryInterface(NS_GET_IID(nsILineIteratorNavigator),getter_AddRefs(it));
-    nsAutoLineIterator it = blockFrame->GetLineIterator();
+    NS_ASSERTION(NS_SUCCEEDED(result) && it, "GetLineNumber() succeeded but no block frame?");
-    NS_ASSERTION(it, "GetLineNumber() succeeded but no block frame?");
 
     PRBool atLineEdge;
     nsIFrame *firstFrame;
     nsIFrame *lastFrame;
 #ifdef IBMBIDI
     if (aVisual && presContext->BidiEnabled()) {
-      PRBool lineIsRTL = it->GetDirection();
+      PRBool lineIsRTL;                                                             
+      it->GetDirection(&lineIsRTL);
       PRBool isReordered;
       result = it->CheckLineOrder(thisLine, &isReordered, &firstFrame, &lastFrame);
       nsIFrame** framePtr = aDirection == eDirPrevious ? &firstFrame : &lastFrame;
@@ -6210,7 +6212,7 @@ nsFrame::RefreshSizeCache(nsBoxLayoutState& aState)
     metrics->mBlockMinSize.height = 0;
     // ok we need the max ascent of the items on the line. So to do this
     // ask the block for its line iterator. Get the max ascent.
-    nsAutoLineIterator lines = GetLineIterator();
+    nsCOMPtr<nsILineIterator> lines = do_QueryInterface(static_cast<nsIFrame*>(this));
     if (lines) 
     {
       metrics->mBlockMinSize.height = 0;
@@ -6253,12 +6255,6 @@ nsFrame::RefreshSizeCache(nsBoxLayoutState& aState)
   return rv;
 }
 
-/* virtual */ nsILineIterator*
-nsFrame::GetLineIterator()
-{
-  return nsnull;
-}
-
 nsSize
 nsFrame::GetPrefSize(nsBoxLayoutState& aState)
 {

layout/generic/nsFrame.h

@@ -621,8 +621,6 @@ private:
 
   NS_IMETHODIMP RefreshSizeCache(nsBoxLayoutState& aState);
 
-  virtual nsILineIterator* GetLineIterator();
-
 protected:
   NS_IMETHOD_(nsrefcnt) AddRef(void);
   NS_IMETHOD_(nsrefcnt) Release(void);

layout/generic/nsFrameList.cpp

@@ -427,6 +427,8 @@ nsFrameList::List(FILE* out) const
 nsIFrame*
 nsFrameList::GetPrevVisualFor(nsIFrame* aFrame) const
 {
+  nsCOMPtr<nsILineIterator> iter;
+
   if (!mFirstChild)
     return nsnull;
   
@@ -437,8 +439,8 @@ nsFrameList::GetPrevVisualFor(nsIFrame* aFrame) const
   nsBidiLevel baseLevel = nsBidiPresUtils::GetFrameBaseLevel(mFirstChild);  
   nsBidiPresUtils* bidiUtils = mFirstChild->PresContext()->GetBidiUtils();
 
-  nsAutoLineIterator iter = parent->GetLineIterator();
+  nsresult result = parent->QueryInterface(NS_GET_IID(nsILineIterator), getter_AddRefs(iter));
-  if (!iter) { 
+  if (NS_FAILED(result) || !iter) { 
     // Parent is not a block Frame
     if (parent->GetType() == nsGkAtoms::lineFrame) {
       // Line frames are not bidi-splittable, so need to consider bidi reordering
@@ -463,11 +465,11 @@ nsFrameList::GetPrevVisualFor(nsIFrame* aFrame) const
 
   PRInt32 thisLine;
   if (aFrame) {
-    thisLine = iter->FindLineContaining(aFrame);
+    result = iter->FindLineContaining(aFrame, &thisLine);
-    if (thisLine < 0)
+    if (NS_FAILED(result) || thisLine < 0)
       return nsnull;
   } else {
-    thisLine = iter->GetNumLines();
+    iter->GetNumLines(&thisLine);
   }
 
   nsIFrame* frame = nsnull;
@@ -502,6 +504,8 @@ nsFrameList::GetPrevVisualFor(nsIFrame* aFrame) const
 nsIFrame*
 nsFrameList::GetNextVisualFor(nsIFrame* aFrame) const
 {
+  nsCOMPtr<nsILineIterator> iter;
+
   if (!mFirstChild)
     return nsnull;
   
@@ -512,8 +516,8 @@ nsFrameList::GetNextVisualFor(nsIFrame* aFrame) const
   nsBidiLevel baseLevel = nsBidiPresUtils::GetFrameBaseLevel(mFirstChild);
   nsBidiPresUtils* bidiUtils = mFirstChild->PresContext()->GetBidiUtils();
   
-  nsAutoLineIterator iter = parent->GetLineIterator();
+  nsresult result = parent->QueryInterface(NS_GET_IID(nsILineIterator), getter_AddRefs(iter));
-  if (!iter) { 
+  if (NS_FAILED(result) || !iter) { 
     // Parent is not a block Frame
     if (parent->GetType() == nsGkAtoms::lineFrame) {
       // Line frames are not bidi-splittable, so need to consider bidi reordering
@@ -538,8 +542,8 @@ nsFrameList::GetNextVisualFor(nsIFrame* aFrame) const
   
   PRInt32 thisLine;
   if (aFrame) {
-    thisLine = iter->FindLineContaining(aFrame);
+    result = iter->FindLineContaining(aFrame, &thisLine);
-    if (thisLine < 0)
+    if (NS_FAILED(result) || thisLine < 0)
       return nsnull;
   } else {
     thisLine = -1;
@@ -561,7 +565,8 @@ nsFrameList::GetNextVisualFor(nsIFrame* aFrame) const
     }
   }
   
-  PRInt32 numLines = iter->GetNumLines();
+  PRInt32 numLines;
+  iter->GetNumLines(&numLines);
   if (!frame && thisLine < numLines - 1) {
     // Get the first frame of the next line
     iter->GetLine(thisLine + 1, &firstFrameOnLine, &numFramesOnLine, lineBounds, &lineFlags);

layout/generic/nsIFrame.h

@@ -85,7 +85,6 @@ class nsIDOMRange;
 class nsISelectionController;
 class nsBoxLayoutState;
 class nsIBoxLayout;
-class nsILineIterator;
 #ifdef ACCESSIBILITY
 class nsIAccessible;
 #endif
@@ -2225,14 +2224,6 @@ NS_PTR_TO_INT32(frame->GetProperty(nsGkAtoms::embeddingLevel))
                                  const nsRect& aOldOverflowRect,
                                  const nsSize& aNewDesiredSize);
 
-  /**
-   * Get a line iterator for this frame, if supported.
-   *
-   * @return nsnull if no line iterator is supported.
-   * @note dispose the line iterator using nsILineIterator::DisposeLineIterator
-   */
-  virtual nsILineIterator* GetLineIterator() = 0;
-
 protected:
   // Members
   nsRect           mRect;

layout/generic/nsILineIterator.h

@@ -37,11 +37,26 @@
 #ifndef nsILineIterator_h___
 #define nsILineIterator_h___
 
-#include "nscore.h"
+#include "nsISupports.h"
-#include "nsCoord.h"
 
-class nsIFrame;
+/* a6cf90ff-15b3-11d2-932e-00805f8add32 */
-struct nsRect;
+#define NS_ILINE_ITERATOR_IID \
+ { 0xa6cf90ff, 0x15b3, 0x11d2,{0x93, 0x2e, 0x00, 0x80, 0x5f, 0x8a, 0xdd, 0x32}}
+
+/* {80AA3D7A-E0BF-4e18-8A82-2110397D7BC4}*/
+#define NS_ILINE_ITERATOR_NAV_IID \
+ { 0x80aa3d7a, 0xe0bf, 0x4e18,{0x8a, 0x82, 0x21, 0x10, 0x39, 0x7d, 0x7b, 0xc4}}
+
+// Line iterator API.
+//
+// Lines are numbered from 0 to N, where 0 is the top line and N is
+// the bottom line.
+//
+// NOTE: while you can get this interface by doing a slezy hacky
+// QueryInterface on block frames, it isn't like a normal com
+// interface: it's not reflexive (you can't query back to the block
+// frame) and unlike other frames, it *IS* reference counted so don't
+// forget to NS_RELEASE it when you are done with it!
 
 // Line Flags (see GetLine below)
 
@@ -52,36 +67,17 @@ struct nsRect;
 // This bit is set when the line ends in some sort of break.
 #define NS_LINE_FLAG_ENDS_IN_BREAK      0x4
 
-/**
+class nsILineIterator : public nsISupports {
- * Line iterator API.
- *
- * Lines are numbered from 0 to N, where 0 is the top line and N is
- * the bottom line.
- *
- * Obtain this interface from frames via nsIFrame::GetLineIterator.
- * When you are finished using the iterator, call DisposeLineIterator()
- * to destroy the iterator if appropriate.
- */
-class nsILineIterator
-{
-protected:
-  ~nsILineIterator() { }
-
 public:
-  virtual void DisposeLineIterator() = 0;
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_ILINE_ITERATOR_IID)
 
-  /**
+  // Return the number of lines in the block.
-   * The number of lines in the block
+  NS_IMETHOD GetNumLines(PRInt32* aResult) = 0;
-   */
-  virtual PRInt32 GetNumLines() = 0;
 
-  /**
+  // Return the prevailing direction for the line. aIsRightToLeft will
-   * The prevailing direction of lines.
+  // be set to PR_TRUE if the CSS direction property for the block is
-   *
+  // "rtl", otherwise aIsRightToLeft will be set to PR_FALSE.
-   * @return PR_TRUE if the CSS direction property for the block is
+  NS_IMETHOD GetDirection(PRBool* aIsRightToLeft) = 0;
-   *         "rtl", otherwise PR_FALSE
-   */
-  virtual PRBool GetDirection() = 0;
 
   // Return structural information about a line. aFirstFrameOnLine is
   // the first frame on the line and aNumFramesOnLine is the number of
@@ -102,20 +98,19 @@ public:
                      nsRect& aLineBounds,
                      PRUint32* aLineFlags) = 0;
 
-  /**
+  // Given a frame that's a child of the block, find which line its on
-   * Given a frame that's a child of the block, find which line its on
+  // and return that line index into aIndexResult. aIndexResult will
-   * and return that line index. Returns -1 if the frame cannot be found.
+  // be set to -1 if the frame cannot be found.
-   */
+  NS_IMETHOD FindLineContaining(nsIFrame* aFrame,
-  virtual PRInt32 FindLineContaining(nsIFrame* aFrame) = 0;
+                                PRInt32* aLineNumberResult) = 0;
 
-  /**
+  // Given a Y coordinate relative to the block that provided this
-   * Given a Y coordinate relative to the block that provided this
+  // line iterator, find the line that contains the Y
-   * line iterator, return the line that contains the Y
+  // coordinate. Returns -1 in aLineNumberResult if the Y coordinate
-   * coordinate. Returns -1 in aLineNumberResult if the Y coordinate
+  // is above the first line. Returns N (where N is the number of
-   *  is above the first line. Returns N (where N is the number of
+  // lines) if the Y coordinate is below the last line.
-   * lines) if the Y coordinate is below the last line.
+  NS_IMETHOD FindLineAt(nscoord aY,
-   */
+                        PRInt32* aLineNumberResult) = 0;
-  virtual PRInt32 FindLineAt(nscoord aY) = 0;
 
   // Given a line number and an X coordinate, find the frame on the
   // line that is nearest to the X coordinate. The
@@ -141,30 +136,15 @@ public:
 #endif
 };
 
-class nsAutoLineIterator
+NS_DEFINE_STATIC_IID_ACCESSOR(nsILineIterator, NS_ILINE_ITERATOR_IID)
-{
+
+//special line iterator for keyboard navigation
+class nsILineIteratorNavigator : public nsILineIterator {
 public:
-  nsAutoLineIterator() : mRawPtr(nsnull) { }
+  NS_DECLARE_STATIC_IID_ACCESSOR(NS_ILINE_ITERATOR_NAV_IID)
-  nsAutoLineIterator(nsILineIterator *i) : mRawPtr(i) { }
-
-  ~nsAutoLineIterator() {
-    if (mRawPtr)
-      mRawPtr->DisposeLineIterator();
-  }
-
-  operator nsILineIterator*() { return mRawPtr; }
-  nsILineIterator* operator->() { return mRawPtr; }
-
-  nsILineIterator* operator=(nsILineIterator* i) {
-    if (mRawPtr)
-      mRawPtr->DisposeLineIterator();
-
-    mRawPtr = i;
-    return i;
-  }
-
-private:
-  nsILineIterator* mRawPtr;
 };
 
+NS_DEFINE_STATIC_IID_ACCESSOR(nsILineIteratorNavigator,
+                              NS_ILINE_ITERATOR_NAV_IID)
+
 #endif /* nsILineIterator_h___ */

layout/generic/nsLineBox.cpp

@@ -543,11 +543,7 @@ nsLineIterator::~nsLineIterator()
   }
 }
 
-/* virtual */ void
+NS_IMPL_ISUPPORTS2(nsLineIterator, nsILineIterator, nsILineIteratorNavigator)
-nsLineIterator::DisposeLineIterator()
-{
-  delete this;
-}
 
 nsresult
 nsLineIterator::Init(nsLineList& aLines, PRBool aRightToLeft)
@@ -582,16 +578,26 @@ nsLineIterator::Init(nsLineList& aLines, PRBool aRightToLeft)
   return NS_OK;
 }
 
-PRInt32
+NS_IMETHODIMP
-nsLineIterator::GetNumLines()
+nsLineIterator::GetNumLines(PRInt32* aResult)
 {
-  return mNumLines;
+  NS_PRECONDITION(aResult, "null OUT ptr");
+  if (!aResult) {
+    return NS_ERROR_NULL_POINTER;
+  }
+  *aResult = mNumLines;
+  return NS_OK;
 }
 
-PRBool
+NS_IMETHODIMP
-nsLineIterator::GetDirection()
+nsLineIterator::GetDirection(PRBool* aIsRightToLeft)
 {
-  return mRightToLeft;
+  NS_PRECONDITION(aIsRightToLeft, "null OUT ptr");
+  if (!aIsRightToLeft) {
+    return NS_ERROR_NULL_POINTER;
+  }
+  *aIsRightToLeft = mRightToLeft;
+  return NS_OK;
 }
 
 NS_IMETHODIMP
@@ -629,35 +635,42 @@ nsLineIterator::GetLine(PRInt32 aLineNumber,
   return NS_OK;
 }
 
-PRInt32
+NS_IMETHODIMP
-nsLineIterator::FindLineContaining(nsIFrame* aFrame)
+nsLineIterator::FindLineContaining(nsIFrame* aFrame,
+                                   PRInt32* aLineNumberResult)
 {
   nsLineBox* line = mLines[0];
   PRInt32 lineNumber = 0;
   while (lineNumber != mNumLines) {
     if (line->Contains(aFrame)) {
-      return lineNumber;
+      *aLineNumberResult = lineNumber;
+      return NS_OK;
     }
     line = mLines[++lineNumber];
   }
-  return -1;
+  *aLineNumberResult = -1;
+  return NS_OK;
 }
 
-/* virtual */ PRInt32
+NS_IMETHODIMP
-nsLineIterator::FindLineAt(nscoord aY)
+nsLineIterator::FindLineAt(nscoord aY,
+                           PRInt32* aLineNumberResult)
 {
   nsLineBox* line = mLines[0];
   if (!line || (aY < line->mBounds.y)) {
-    return -1;
+    *aLineNumberResult = -1;
+    return NS_OK;
   }
   PRInt32 lineNumber = 0;
   while (lineNumber != mNumLines) {
     if ((aY >= line->mBounds.y) && (aY < line->mBounds.YMost())) {
-      return lineNumber;
+      *aLineNumberResult = lineNumber;
+      return NS_OK;
     }
     line = mLines[++lineNumber];
   }
-  return mNumLines;
+  *aLineNumberResult = mNumLines;
+  return NS_OK;
 }
 
 #ifdef IBMBIDI

layout/generic/nsLineBox.h

@@ -1508,23 +1508,24 @@ nsLineList_const_reverse_iterator::operator=(const nsLineList_const_reverse_iter
 
 //----------------------------------------------------------------------
 
-class NS_FINAL_CLASS nsLineIterator : public nsILineIterator
+class nsLineIterator : public nsILineIteratorNavigator {
-{
 public:
   nsLineIterator();
-  ~nsLineIterator();
+  virtual ~nsLineIterator();
 
-  virtual void DisposeLineIterator();
+  NS_DECL_ISUPPORTS
 
-  virtual PRInt32 GetNumLines();
+  NS_IMETHOD GetNumLines(PRInt32* aResult);
-  virtual PRBool GetDirection();
+  NS_IMETHOD GetDirection(PRBool* aIsRightToLeft);
   NS_IMETHOD GetLine(PRInt32 aLineNumber,
                      nsIFrame** aFirstFrameOnLine,
                      PRInt32* aNumFramesOnLine,
                      nsRect& aLineBounds,
                      PRUint32* aLineFlags);
-  virtual PRInt32 FindLineContaining(nsIFrame* aFrame);
+  NS_IMETHOD FindLineContaining(nsIFrame* aFrame,
-  virtual PRInt32 FindLineAt(nscoord aY);
+                                PRInt32* aLineNumberResult);
+  NS_IMETHOD FindLineAt(nscoord aY,
+                        PRInt32* aLineNumberResult);
   NS_IMETHOD FindFrameAt(PRInt32 aLineNumber,
                          nscoord aX,
                          nsIFrame** aFrameFound,
@@ -1540,7 +1541,15 @@ public:
 #endif
   nsresult Init(nsLineList& aLines, PRBool aRightToLeft);
 
-private:
+protected:
+  PRInt32 NumLines() const {
+    return mNumLines;
+  }
+
+  nsLineBox* CurrentLine() {
+    return mLines[mIndex];
+  }
+
   nsLineBox* PrevLine() {
     if (0 == mIndex) {
       return nsnull;

layout/tables/nsTableRowGroupFrame.cpp

@@ -64,6 +64,17 @@ nsTableRowGroupFrame::~nsTableRowGroupFrame()
 {
 }
 
+/* ----------- nsTableRowGroupFrame ---------- */
+nsrefcnt nsTableRowGroupFrame::AddRef(void)
+{
+  return 1;//implementation of nsLineIterator
+}
+
+nsrefcnt nsTableRowGroupFrame::Release(void)
+{
+  return 1;//implementation of nsLineIterator
+}
+
 NS_IMETHODIMP
 nsTableRowGroupFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
 {
@@ -74,6 +85,14 @@ nsTableRowGroupFrame::QueryInterface(const nsIID& aIID, void** aInstancePtr)
     *aInstancePtr = (void*)this;
     return NS_OK;
   }
+  if (aIID.Equals(NS_GET_IID(nsILineIteratorNavigator))) {
+    *aInstancePtr = static_cast<nsILineIteratorNavigator*>(this);
+    return NS_OK;
+  }
+  if (aIID.Equals(NS_GET_IID(nsILineIterator))) {
+    *aInstancePtr = static_cast<nsILineIterator*>(this);
+    return NS_OK;
+  }
 
   return nsHTMLContainerFrame::QueryInterface(aIID, aInstancePtr);
 }
@@ -1634,18 +1653,23 @@ void nsTableRowGroupFrame::SetContinuousBCBorderWidth(PRUint8     aForSide,
 }
 
 //nsILineIterator methods
-PRInt32
+NS_IMETHODIMP
-nsTableRowGroupFrame::GetNumLines()
+nsTableRowGroupFrame::GetNumLines(PRInt32* aResult)
 {
-  return GetRowCount();
+  NS_ENSURE_ARG_POINTER(aResult);
+  *aResult = GetRowCount();
+  return NS_OK;
 }
 
-PRBool
+NS_IMETHODIMP
-nsTableRowGroupFrame::GetDirection()
+nsTableRowGroupFrame::GetDirection(PRBool* aIsRightToLeft)
 {
+  NS_ENSURE_ARG_POINTER(aIsRightToLeft);
+  // rtl is table wide @see nsTableIterator
   nsTableFrame* table = nsTableFrame::GetTableFrame(this);
-  return (NS_STYLE_DIRECTION_RTL ==
+  *aIsRightToLeft = (NS_STYLE_DIRECTION_RTL ==
-          table->GetStyleVisibility()->mDirection);
+                     table->GetStyleVisibility()->mDirection);
+  return NS_OK;
 }
   
 NS_IMETHODIMP
@@ -1690,25 +1714,28 @@ nsTableRowGroupFrame::GetLine(PRInt32    aLineNumber,
   return NS_ERROR_FAILURE;
 }
   
-PRInt32
+NS_IMETHODIMP
-nsTableRowGroupFrame::FindLineContaining(nsIFrame* aFrame)
+nsTableRowGroupFrame::FindLineContaining(nsIFrame* aFrame, 
+                                         PRInt32*  aLineNumberResult)
 {
   NS_ENSURE_ARG_POINTER(aFrame);
+  NS_ENSURE_ARG_POINTER(aLineNumberResult);
   
   NS_ASSERTION((aFrame->GetType() == nsGkAtoms::tableRowFrame),
                "RowGroup contains a frame that is not a row");
 
   nsTableRowFrame* rowFrame = (nsTableRowFrame*)aFrame;
-  return rowFrame->GetRowIndex() - GetStartRowIndex();
+  *aLineNumberResult = rowFrame->GetRowIndex() - GetStartRowIndex();
+
+  return NS_OK;
 }
 
-PRInt32
+NS_IMETHODIMP
-nsTableRowGroupFrame::FindLineAt(nscoord  aY)
+nsTableRowGroupFrame::FindLineAt(nscoord  aY, 
+                                 PRInt32* aLineNumberResult)
 {
-  NS_NOTREACHED("Not implemented");
   return NS_ERROR_NOT_IMPLEMENTED;
 }
-
 #ifdef IBMBIDI
 NS_IMETHODIMP
 nsTableRowGroupFrame::CheckLineOrder(PRInt32                  aLine,

layout/tables/nsTableRowGroupFrame.h

@@ -96,12 +96,11 @@ struct nsRowGroupReflowState {
  * @see nsTableFrame
  * @see nsTableRowFrame
  */
-class nsTableRowGroupFrame
+class nsTableRowGroupFrame : public nsHTMLContainerFrame, public nsILineIteratorNavigator
-  : public nsHTMLContainerFrame
-  , public nsILineIterator
 {
 public:
-  NS_IMETHOD QueryInterface(const nsIID &aIID, void **aInstancePtr);
+  // nsISupports
+  NS_DECL_ISUPPORTS_INHERITED
 
   /** instantiate a new instance of nsTableRowFrame.
     * @param aPresShell the pres shell for this frame
@@ -228,8 +227,6 @@ public:
 
 // nsILineIterator methods
 public:
-  virtual void DisposeLineIterator() { }
-
   // The table row is the equivalent to a line in block layout. 
   // The nsILineIterator assumes that a line resides in a block, this role is
   // fullfilled by the row group. Rows in table are counted relative to the
@@ -238,14 +235,14 @@ public:
   // row index of the first row in the row group.
    
   /** Get the number of rows in a row group
-    * @return the number of lines in a row group
+    * @param aResult - pointer that holds the number of lines in a row group
     */
-  virtual PRInt32 GetNumLines();
+  NS_IMETHOD GetNumLines(PRInt32* aResult);
 
   /** @see nsILineIterator.h GetDirection
-    * @return true if the table is rtl
+    * @param aIsRightToLeft - true if the table is rtl
     */
-  virtual PRBool GetDirection();
+  NS_IMETHOD GetDirection(PRBool* aIsRightToLeft);
   
   /** Return structural information about a line. 
     * @param aLineNumber       - the index of the row relative to the row group
@@ -267,15 +264,16 @@ public:
   
   /** Given a frame that's a child of the rowgroup, find which line its on.
     * @param aFrame       - frame, should be a row
-    * @return               row index relative to the row group if this a row
+    * @param aIndexResult - row index relative to the row group if this a row
-    *                       frame. -1 if the frame cannot be found.
+    *                       frame. aIndexResult will be set to -1 if the frame
+    *                       cannot be found.
     */
-  virtual PRInt32 FindLineContaining(nsIFrame* aFrame);
+  NS_IMETHOD FindLineContaining(nsIFrame* aFrame, PRInt32* aLineNumberResult);
   
   /** not implemented
     * the function is also not called in our tree
     */
-  virtual PRInt32 FindLineAt(nscoord aY);
+  NS_IMETHOD FindLineAt(nscoord aY, PRInt32* aLineNumberResult);
 
   /** Find the orginating cell frame on a row that is the nearest to the
     * coordinate X.
@@ -375,8 +373,6 @@ public:
            GetStyleDisplay()->mOverflowY == NS_STYLE_OVERFLOW_CLIP;
   }
 
-  virtual nsILineIterator* GetLineIterator() { return this; }
-
 protected:
   nsTableRowGroupFrame(nsStyleContext* aContext);