Enable PeekOffset to find the visual beginning/end of a line, and use use it for bidi caret positioning. bug=302051 r=smontagu sr=roc

layout/base/nsCaret.cpp

@@ -731,19 +731,15 @@ nsCaret::GetCaretFrameForNodeOffset(nsIContent*             aContentNode,
                 // if there is no frameBefore, we must be at the beginning of the line
                 // so we stay with the current frame.
                 // Exception: when the first frame on the line has a different Bidi level from the paragraph level, there is no
-                // real frame for the caret to be in. We have to find the first frame whose level is the same as the
-                // paragraph level, and put the caret at the end of the frame before that.
+                // real frame for the caret to be in. We have to find the visually first frame on the line.
                 PRUint8 baseLevel = NS_GET_BASE_LEVEL(frameAfter);
                 if (baseLevel != levelAfter)
                 {
-                  if (NS_SUCCEEDED(frameSelection->GetFrameFromLevel(frameAfter, eDirNext, baseLevel, &theFrame)))
-                  {
-                    theFrame->GetOffsets(start, end);
-                    levelAfter = NS_GET_EMBEDDING_LEVEL(theFrame);
-                    if (baseLevel & 1) // RTL paragraph: caret to the right of the rightmost character
-                      theFrameOffset = (levelAfter & 1) ? start : end;
-                    else               // LTR paragraph: caret to the left of the leftmost character
-                      theFrameOffset = (levelAfter & 1) ? end : start;
+                  nsPeekOffsetStruct pos;
+                  pos.SetData(eSelectBeginLine, eDirPrevious, 0, 0, PR_FALSE, PR_TRUE, PR_FALSE, PR_TRUE);
+                  if (NS_SUCCEEDED(frameAfter->PeekOffset(presContext, &pos))) {
+                    theFrame = pos.mResultFrame;
+                    theFrameOffset = pos.mContentOffset;
                   }
                 }
               }
@@ -766,22 +762,16 @@ nsCaret::GetCaretFrameForNodeOffset(nsIContent*             aContentNode,
               {
                 // if there is no frameAfter, we must be at the end of the line
                 // so we stay with the current frame.
-                //
                 // Exception: when the last frame on the line has a different Bidi level from the paragraph level, there is no
-                // real frame for the caret to be in. We have to find the last frame whose level is the same as the
-                // paragraph level, and put the caret at the end of the frame after that.
-
+                // real frame for the caret to be in. We have to find the visually last frame on the line.
                 PRUint8 baseLevel = NS_GET_BASE_LEVEL(frameBefore);
                 if (baseLevel != levelBefore)
                 {
-                  if (NS_SUCCEEDED(frameSelection->GetFrameFromLevel(frameBefore, eDirPrevious, baseLevel, &theFrame)))
-                  {
-                    theFrame->GetOffsets(start, end);
-                    levelBefore = NS_GET_EMBEDDING_LEVEL(theFrame);
-                    if (baseLevel & 1) // RTL paragraph: caret to the left of the leftmost character
-                      theFrameOffset = (levelBefore & 1) ? end : start;
-                    else               // RTL paragraph: caret to the right of the rightmost character
-                      theFrameOffset = (levelBefore & 1) ? start : end;
+                  nsPeekOffsetStruct pos;
+                  pos.SetData(eSelectEndLine, eDirNext, 0, 0, PR_FALSE, PR_TRUE, PR_FALSE, PR_TRUE);
+                  if (NS_SUCCEEDED(frameBefore->PeekOffset(presContext, &pos))) {
+                    theFrame = pos.mResultFrame;
+                    theFrameOffset = pos.mContentOffset;
                   }
                 }
               }

layout/generic/nsFrame.cpp

@@ -4364,17 +4364,35 @@ nsFrame::PeekOffset(nsPresContext* aPresContext, nsPeekOffsetStruct *aPos)
       nsIFrame *firstFrame;
       nsRect usedRect;
       PRUint32 lineFlags;
-      it->GetLine(thisLine, &firstFrame, &lineFrameCount, usedRect, &lineFlags);
-
-      PRBool endOfLine = (eSelectEndLine == aPos->mAmount);
       nsIFrame* baseFrame = nsnull;
-      nsIFrame* frame = firstFrame;
-      for (PRInt32 count = lineFrameCount; count;
-           --count, frame = frame->GetNextSibling()) {
-        if (!frame->IsGeneratedContentFrame()) {
-          baseFrame = frame;
-          if (!endOfLine)
-            break;
+      PRBool endOfLine = (eSelectEndLine == aPos->mAmount);
+      
+#ifdef IBMBIDI
+      if (aPos->mVisual && aPresContext->BidiEnabled()) {
+        PRBool lineIsRTL;
+        it->GetDirection(&lineIsRTL);
+        PRBool isReordered;
+        nsIFrame *lastFrame;
+        result = it->CheckLineOrder(thisLine, &isReordered, &firstFrame, &lastFrame);
+        baseFrame = endOfLine ? lastFrame : firstFrame;
+        nsBidiLevel embeddingLevel = nsBidiPresUtils::GetFrameEmbeddingLevel(baseFrame);
+        // If the direction of the frame on the edge is opposite to that of the line,
+        // we'll need to drill down to its opposite end, so reverse endOfLine.
+        if ((embeddingLevel & 1) == !lineIsRTL)
+          endOfLine = !endOfLine;
+      } else
+#endif
+      {
+        it->GetLine(thisLine, &firstFrame, &lineFrameCount, usedRect, &lineFlags);
+
+        nsIFrame* frame = firstFrame;
+        for (PRInt32 count = lineFrameCount; count;
+             --count, frame = frame->GetNextSibling()) {
+          if (!frame->IsGeneratedContentFrame()) {
+            baseFrame = frame;
+            if (!endOfLine)
+              break;
+          }
         }
       }
       if (!baseFrame)
@@ -4384,6 +4402,7 @@ nsFrame::PeekOffset(nsPresContext* aPresContext, nsPeekOffsetStruct *aPos)
       FrameContentRange range = GetRangeForFrame(targetFrame.frame);
       aPos->mResultContent = range.content;
       aPos->mContentOffset = endOfLine ? range.end : range.start;
+      aPos->mResultFrame = targetFrame.frame;
       aPos->mAttachForward = (aPos->mContentOffset == range.start);
       if (!range.content)
         return NS_ERROR_FAILURE;

layout/generic/nsFrameSelection.h

@@ -125,7 +125,7 @@ struct nsPeekOffsetStruct
   PRBool mIsKeyboardSelect;
 
   // mVisual: Whether bidi caret behavior is visual (PR_TRUE) or logical (PR_FALSE).
-  //          Used with: eSelectCharacter, eSelectWord.
+  //          Used with: eSelectCharacter, eSelectWord, eSelectBeginLine, eSelectEndLine.
   PRBool mVisual;
 
   // mWordMovementType: An enum that determines whether to prefer the start or end of a word

layout/generic/nsSelection.cpp

@@ -1264,8 +1264,10 @@ nsFrameSelection::MoveCaret(PRUint32          aKeycode,
 
   PRBool visualMovement = 
     (aKeycode == nsIDOMKeyEvent::DOM_VK_BACK_SPACE || 
-     aKeycode == nsIDOMKeyEvent::DOM_VK_DELETE) ?
-    PR_FALSE : // Delete operations are always logical
+     aKeycode == nsIDOMKeyEvent::DOM_VK_DELETE ||
+     aKeycode == nsIDOMKeyEvent::DOM_VK_HOME || 
+     aKeycode == nsIDOMKeyEvent::DOM_VK_END) ?
+    PR_FALSE : // Delete operations and home/end are always logical
     mCaretMovementStyle == 1 || (mCaretMovementStyle == 2 && !aContinueSelection);
 
   //set data using mLimiter to stop on scroll views.  If we have a limiter then we stop peeking