The Tor Browser: layout/base/nsBidiPresUtils.cpp@6474c204b198 (annotated)

layout/base/nsBidiPresUtils.cpp@6474c204b198 (annotated)

layout/base/nsBidiPresUtils.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "nsBidiPresUtils.h"
 #include "nsGkAtoms.h"
 #include "nsPresContext.h"
 #include "nsRenderingContext.h"
 #include "nsBidiUtils.h"
 #include "nsCSSFrameConstructor.h"
 #include "nsContainerFrame.h"
 #include "nsInlineFrame.h"
 #include "nsPlaceholderFrame.h"
 #include "nsFirstLetterFrame.h"
 #include "nsUnicodeProperties.h"
 #include "nsTextFrame.h"
 #include "nsBlockFrame.h"
 #include "nsIFrameInlines.h"
 #include <algorithm>
 #undef NOISY_BIDI
 #undef REALLY_NOISY_BIDI
 using namespace mozilla;
 static const char16_t kSpace            = 0x0020;
 static const char16_t kZWSP             = 0x200B;
 static const char16_t kLineSeparator    = 0x2028;
 static const char16_t kObjectSubstitute = 0xFFFC;
 static const char16_t kLRE              = 0x202A;
 static const char16_t kRLE              = 0x202B;
 static const char16_t kLRO              = 0x202D;
 static const char16_t kRLO              = 0x202E;
 static const char16_t kPDF              = 0x202C;
 static const char16_t kSeparators[] = {
   // All characters with Bidi type Segment Separator or Block Separator
   char16_t('\t'),
   char16_t('\r'),
   char16_t('\n'),
   char16_t(0xb),
   char16_t(0x1c),
   char16_t(0x1d),
   char16_t(0x1e),
   char16_t(0x1f),
   char16_t(0x85),
   char16_t(0x2029),
   char16_t(0)
 };
 #define NS_BIDI_CONTROL_FRAME ((nsIFrame*)0xfffb1d1)
 struct BidiParagraphData {
   nsString            mBuffer;
   nsAutoTArray<char16_t, 16> mEmbeddingStack;
   nsTArray<nsIFrame*> mLogicalFrames;
   nsTArray<nsLineBox*> mLinePerFrame;
   nsDataHashtable<nsISupportsHashKey, int32_t> mContentToFrameIndex;
   bool                mIsVisual;
   bool                mReset;
   nsBidiLevel         mParaLevel;
   nsIContent*         mPrevContent;
   nsAutoPtr<nsBidi>   mBidiEngine;
   nsIFrame*           mPrevFrame;
   nsAutoPtr<BidiParagraphData> mSubParagraph;
   uint8_t             mParagraphDepth;
   void Init(nsBlockFrame *aBlockFrame)
   {
     mBidiEngine = new nsBidi();
     mPrevContent = nullptr;
     mParagraphDepth = 0;
     mParaLevel = nsBidiPresUtils::BidiLevelFromStyle(aBlockFrame->StyleContext());
     mIsVisual = aBlockFrame->PresContext()->IsVisualMode();
     if (mIsVisual) {
       /**
        * Drill up in content to detect whether this is an element that needs to
        * be rendered with logical order even on visual pages.
        *
        * We always use logical order on form controls, firstly so that text
        * entry will be in logical order, but also because visual pages were
        * written with the assumption that even if the browser had no support
        * for right-to-left text rendering, it would use native widgets with
        * bidi support to display form controls.
        *
        * We also use logical order in XUL elements, since we expect that if a
        * XUL element appears in a visual page, it will be generated by an XBL
        * binding and contain localized text which will be in logical order.
        */
       for (nsIContent* content = aBlockFrame->GetContent() ; content;
            content = content->GetParent()) {
         if (content->IsNodeOfType(nsINode::eHTML_FORM_CONTROL) ||
             content->IsXUL()) {
           mIsVisual = false;
           break;
         }
       }
     }
   }
   BidiParagraphData* GetSubParagraph()
   {
     if (!mSubParagraph) {
       mSubParagraph = new BidiParagraphData();
       mSubParagraph->Init(this);
     }
     return mSubParagraph;
   }
   // Initialise a sub-paragraph from its containing paragraph
   void Init(BidiParagraphData *aBpd)
   {
     mBidiEngine = new nsBidi();
     mPrevContent = nullptr;
     mIsVisual = aBpd->mIsVisual;
     mReset = false;
   }
   void Reset(nsIFrame* aBDIFrame, BidiParagraphData *aBpd)
   {
     mReset = true;
     mLogicalFrames.Clear();
     mLinePerFrame.Clear();
     mContentToFrameIndex.Clear();
     mBuffer.SetLength(0);
     mPrevFrame = aBpd->mPrevFrame;
     mParagraphDepth = aBpd->mParagraphDepth + 1;
     const nsStyleTextReset* text = aBDIFrame->StyleTextReset();
     bool isRTL = (NS_STYLE_DIRECTION_RTL ==
                   aBDIFrame->StyleVisibility()->mDirection);
     if (text->mUnicodeBidi & NS_STYLE_UNICODE_BIDI_PLAINTEXT) {
       mParaLevel = NSBIDI_DEFAULT_LTR;
     } else {
       mParaLevel = mParagraphDepth * 2;
       if (isRTL) ++mParaLevel;
     }
     if (text->mUnicodeBidi & NS_STYLE_UNICODE_BIDI_OVERRIDE) {
       PushBidiControl(isRTL ? kRLO : kLRO);
     }
   }
   void EmptyBuffer()
   {
     mBuffer.SetLength(0);
   }
   nsresult SetPara()
   {
     return mBidiEngine->SetPara(mBuffer.get(), BufferLength(),
                                 mParaLevel, nullptr);
   }
   /**
    * mParaLevel can be NSBIDI_DEFAULT_LTR as well as NSBIDI_LTR or NSBIDI_RTL.
    * GetParaLevel() returns the actual (resolved) paragraph level which is
    * always either NSBIDI_LTR or NSBIDI_RTL
    */
   nsBidiLevel GetParaLevel()
   {
     nsBidiLevel paraLevel = mParaLevel;
     if (IS_DEFAULT_LEVEL(paraLevel)) {
       mBidiEngine->GetParaLevel(&paraLevel);
     }
     return paraLevel;
   }
   nsBidiDirection GetDirection()
   {
     nsBidiDirection dir;
     mBidiEngine->GetDirection(&dir);
     return dir;
   }
   nsresult CountRuns(int32_t *runCount){ return mBidiEngine->CountRuns(runCount); }
   nsresult GetLogicalRun(int32_t aLogicalStart,
                          int32_t* aLogicalLimit,
                          nsBidiLevel* aLevel)
   {
     nsresult rv = mBidiEngine->GetLogicalRun(aLogicalStart,
                                              aLogicalLimit, aLevel);
     if (mIsVisual || NS_FAILED(rv))
       *aLevel = GetParaLevel();
     return rv;
   }
   void ResetData()
   {
     mLogicalFrames.Clear();
     mLinePerFrame.Clear();
     mContentToFrameIndex.Clear();
     mBuffer.SetLength(0);
     mPrevContent = nullptr;
     for (uint32_t i = 0; i < mEmbeddingStack.Length(); ++i) {
       mBuffer.Append(mEmbeddingStack[i]);
       mLogicalFrames.AppendElement(NS_BIDI_CONTROL_FRAME);
       mLinePerFrame.AppendElement((nsLineBox*)nullptr);
     }
   }
   void ResetForNewBlock()
   {
     for (BidiParagraphData* bpd = this; bpd; bpd = bpd->mSubParagraph) {
       bpd->mPrevFrame = nullptr;
     }
   }
   void AppendFrame(nsIFrame* aFrame,
                    nsBlockInFlowLineIterator* aLineIter,
                    nsIContent* aContent = nullptr)
   {
     if (aContent) {
       mContentToFrameIndex.Put(aContent, FrameCount());
     }
     mLogicalFrames.AppendElement(aFrame);
     AdvanceLineIteratorToFrame(aFrame, aLineIter, mPrevFrame);
     mLinePerFrame.AppendElement(aLineIter->GetLine().get());
   }
   void AdvanceAndAppendFrame(nsIFrame** aFrame,
                              nsBlockInFlowLineIterator* aLineIter,
                              nsIFrame** aNextSibling)
   {
     nsIFrame* frame = *aFrame;
     nsIFrame* nextSibling = *aNextSibling;
     frame = frame->GetNextContinuation();
     if (frame) {
       AppendFrame(frame, aLineIter, nullptr);
       /*
        * If we have already overshot the saved next-sibling while
        * scanning the frame's continuations, advance it.
        */
       if (frame == nextSibling) {
         nextSibling = frame->GetNextSibling();
       }
     }
     *aFrame = frame;
     *aNextSibling = nextSibling;
   }
   int32_t GetLastFrameForContent(nsIContent *aContent)
   {
     int32_t index = 0;
     mContentToFrameIndex.Get(aContent, &index);
     return index;
   }
   int32_t FrameCount(){ return mLogicalFrames.Length(); }
   int32_t BufferLength(){ return mBuffer.Length(); }
   nsIFrame* FrameAt(int32_t aIndex){ return mLogicalFrames[aIndex]; }
   nsLineBox* GetLineForFrameAt(int32_t aIndex){ return mLinePerFrame[aIndex]; }
   void AppendUnichar(char16_t aCh){ mBuffer.Append(aCh); }
   void AppendString(const nsDependentSubstring& aString){ mBuffer.Append(aString); }
   void AppendControlChar(char16_t aCh)
   {
     mLogicalFrames.AppendElement(NS_BIDI_CONTROL_FRAME);
     mLinePerFrame.AppendElement((nsLineBox*)nullptr);
     AppendUnichar(aCh);
   }
   void PushBidiControl(char16_t aCh)
   {
     AppendControlChar(aCh);
     mEmbeddingStack.AppendElement(aCh);
   }
   void PopBidiControl()
   {
     AppendControlChar(kPDF);
     NS_ASSERTION(mEmbeddingStack.Length(), "embedding/override underflow");
     mEmbeddingStack.TruncateLength(mEmbeddingStack.Length() - 1);
   }
   void ClearBidiControls()
   {
     for (uint32_t i = 0; i < mEmbeddingStack.Length(); ++i) {
       AppendControlChar(kPDF);
     }
   }
   static bool
   IsFrameInCurrentLine(nsBlockInFlowLineIterator* aLineIter,
                        nsIFrame* aPrevFrame, nsIFrame* aFrame)
   {
     nsIFrame* endFrame = aLineIter->IsLastLineInList() ? nullptr :
       aLineIter->GetLine().next()->mFirstChild;
     nsIFrame* startFrame = aPrevFrame ? aPrevFrame : aLineIter->GetLine()->mFirstChild;
     for (nsIFrame* frame = startFrame; frame && frame != endFrame;
          frame = frame->GetNextSibling()) {
       if (frame == aFrame)
         return true;
     }
     return false;
   }
   static void
   AdvanceLineIteratorToFrame(nsIFrame* aFrame,
                              nsBlockInFlowLineIterator* aLineIter,
                              nsIFrame*& aPrevFrame)
   {
     // Advance aLine to the line containing aFrame
     nsIFrame* child = aFrame;
     nsIFrame* parent = nsLayoutUtils::GetParentOrPlaceholderFor(child);
     while (parent && !nsLayoutUtils::GetAsBlock(parent)) {
       child = parent;
       parent = nsLayoutUtils::GetParentOrPlaceholderFor(child);
     }
     NS_ASSERTION (parent, "aFrame is not a descendent of aBlockFrame");
     while (!IsFrameInCurrentLine(aLineIter, aPrevFrame, child)) {
 #ifdef DEBUG
       bool hasNext =
 #endif
         aLineIter->Next();
       NS_ASSERTION(hasNext, "Can't find frame in lines!");
       aPrevFrame = nullptr;
     }
     aPrevFrame = child;
   }
 };
 struct BidiLineData {
   nsTArray<nsIFrame*> mLogicalFrames;
   nsTArray<nsIFrame*> mVisualFrames;
   nsTArray<int32_t> mIndexMap;
   nsAutoTArray<uint8_t, 18> mLevels;
   bool mIsReordered;
   BidiLineData(nsIFrame* aFirstFrameOnLine, int32_t   aNumFramesOnLine)
   {
     /**
      * Initialize the logically-ordered array of frames using the top-level
      * frames of a single line
      */
     mLogicalFrames.Clear();
     bool isReordered = false;
     bool hasRTLFrames = false;
     for (nsIFrame* frame = aFirstFrameOnLine;
          frame && aNumFramesOnLine--;
          frame = frame->GetNextSibling()) {
       AppendFrame(frame);
       uint8_t level = nsBidiPresUtils::GetFrameEmbeddingLevel(frame);
       mLevels.AppendElement(level);
       mIndexMap.AppendElement(0);
       if (level & 1) {
         hasRTLFrames = true;
       }
     }
     // Reorder the line
     nsBidi::ReorderVisual(mLevels.Elements(), FrameCount(),
                           mIndexMap.Elements());
     for (int32_t i = 0; i < FrameCount(); i++) {
       mVisualFrames.AppendElement(LogicalFrameAt(mIndexMap[i]));
       if (i != mIndexMap[i]) {
         isReordered = true;
       }
     }
     // If there's an RTL frame, assume the line is reordered
     mIsReordered = isReordered || hasRTLFrames;
   }
   void AppendFrame(nsIFrame* aFrame)
   {
     mLogicalFrames.AppendElement(aFrame);
   }
   int32_t FrameCount(){ return mLogicalFrames.Length(); }
   nsIFrame* LogicalFrameAt(int32_t aIndex){ return mLogicalFrames[aIndex]; }
   nsIFrame* VisualFrameAt(int32_t aIndex){ return mVisualFrames[aIndex]; }
 };
 /* Some helper methods for Resolve() */
 // Should this frame be split between text runs?
 static bool
 IsBidiSplittable(nsIFrame* aFrame)
 {
   // Bidi inline containers should be split, unless they're line frames.
   nsIAtom* frameType = aFrame->GetType();
   return (aFrame->IsFrameOfType(nsIFrame::eBidiInlineContainer) &&
           frameType != nsGkAtoms::lineFrame) ||
          frameType == nsGkAtoms::textFrame;
 }
 // Should this frame be treated as a leaf (e.g. when building mLogicalFrames)?
 static bool
 IsBidiLeaf(nsIFrame* aFrame)
 {
   nsIFrame* kid = aFrame->GetFirstPrincipalChild();
   return !kid || !aFrame->IsFrameOfType(nsIFrame::eBidiInlineContainer);
 }
 /**
  * Create non-fluid continuations for the ancestors of a given frame all the way
  * up the frame tree until we hit a non-splittable frame (a line or a block).
  *
  * @param aParent the first parent frame to be split
  * @param aFrame the child frames after this frame are reparented to the
  *        newly-created continuation of aParent.
  *        If aFrame is null, all the children of aParent are reparented.
  */
 static nsresult
 SplitInlineAncestors(nsIFrame* aParent,
                      nsIFrame* aFrame)
 {
   nsPresContext *presContext = aParent->PresContext();
   nsIPresShell *presShell = presContext->PresShell();
   nsIFrame* frame = aFrame;
   nsIFrame* parent = aParent;
   nsIFrame* newParent;
   while (IsBidiSplittable(parent)) {
     nsIFrame* grandparent = parent->GetParent();
     NS_ASSERTION(grandparent, "Couldn't get parent's parent in nsBidiPresUtils::SplitInlineAncestors");
     // Split the child list after |frame|, unless it is the last child.
     if (!frame || frame->GetNextSibling()) {
       newParent = presShell->FrameConstructor()->
         CreateContinuingFrame(presContext, parent, grandparent, false);
       nsContainerFrame* container = do_QueryFrame(parent);
       nsFrameList tail = container->StealFramesAfter(frame);
       // Reparent views as necessary
       nsresult rv;
       rv = nsContainerFrame::ReparentFrameViewList(tail, parent, newParent);
       if (NS_FAILED(rv)) {
         return rv;
       }
       // The parent's continuation adopts the siblings after the split.
       rv = newParent->InsertFrames(nsIFrame::kNoReflowPrincipalList, nullptr, tail);
       if (NS_FAILED(rv)) {
         return rv;
       }
       // The list name kNoReflowPrincipalList would indicate we don't want reflow
       nsFrameList temp(newParent, newParent);
       rv = grandparent->InsertFrames(nsIFrame::kNoReflowPrincipalList, parent, temp);
       if (NS_FAILED(rv)) {
         return rv;
       }
     }
     frame = parent;
     parent = grandparent;
   }
   return NS_OK;
 }
 static void
 MakeContinuationFluid(nsIFrame* aFrame, nsIFrame* aNext)
 {
   NS_ASSERTION (!aFrame->GetNextInFlow() || aFrame->GetNextInFlow() == aNext,
                 "next-in-flow is not next continuation!");
   aFrame->SetNextInFlow(aNext);
   NS_ASSERTION (!aNext->GetPrevInFlow() || aNext->GetPrevInFlow() == aFrame,
                 "prev-in-flow is not prev continuation!");
   aNext->SetPrevInFlow(aFrame);
 }
 static void
 MakeContinuationsNonFluidUpParentChain(nsIFrame* aFrame, nsIFrame* aNext)
 {
   nsIFrame* frame;
   nsIFrame* next;
   for (frame = aFrame, next = aNext;
        frame && next &&
          next != frame && next == frame->GetNextInFlow() &&
          IsBidiSplittable(frame);
        frame = frame->GetParent(), next = next->GetParent()) {
     frame->SetNextContinuation(next);
     next->SetPrevContinuation(frame);
   }
 }
 // If aFrame is the last child of its parent, convert bidi continuations to
 // fluid continuations for all of its inline ancestors.
 // If it isn't the last child, make sure that its continuation is fluid.
 static void
 JoinInlineAncestors(nsIFrame* aFrame)
 {
   nsIFrame* frame = aFrame;
   do {
     nsIFrame* next = frame->GetNextContinuation();
     if (next) {
       // Don't join frames if they come from different paragraph depths (i.e.
       // one is bidi isolated relative to the other
       if (nsBidiPresUtils::GetParagraphDepth(frame) ==
           nsBidiPresUtils::GetParagraphDepth(next)) {
         MakeContinuationFluid(frame, next);
       }
     }
     // Join the parent only as long as we're its last child.
     if (frame->GetNextSibling())
       break;
     frame = frame->GetParent();
   } while (frame && IsBidiSplittable(frame));
 }
 static nsresult
 CreateContinuation(nsIFrame*  aFrame,
                    nsIFrame** aNewFrame,
                    bool       aIsFluid)
 {
   NS_PRECONDITION(aNewFrame, "null OUT ptr");
   NS_PRECONDITION(aFrame, "null ptr");
   *aNewFrame = nullptr;
   nsPresContext *presContext = aFrame->PresContext();
   nsIPresShell *presShell = presContext->PresShell();
   NS_ASSERTION(presShell, "PresShell must be set on PresContext before calling nsBidiPresUtils::CreateContinuation");
   nsIFrame* parent = aFrame->GetParent();
   NS_ASSERTION(parent, "Couldn't get frame parent in nsBidiPresUtils::CreateContinuation");
   nsresult rv = NS_OK;
   // Have to special case floating first letter frames because the continuation
   // doesn't go in the first letter frame. The continuation goes with the rest
   // of the text that the first letter frame was made out of.
   if (parent->GetType() == nsGkAtoms::letterFrame &&
       parent->IsFloating()) {
     nsFirstLetterFrame* letterFrame = do_QueryFrame(parent);
     rv = letterFrame->CreateContinuationForFloatingParent(presContext, aFrame,
                                                           aNewFrame, aIsFluid);
     return rv;
   }
   *aNewFrame = presShell->FrameConstructor()->
     CreateContinuingFrame(presContext, aFrame, parent, aIsFluid);
   // The list name kNoReflowPrincipalList would indicate we don't want reflow
   // XXXbz this needs higher-level framelist love
   nsFrameList temp(*aNewFrame, *aNewFrame);
   rv = parent->InsertFrames(nsIFrame::kNoReflowPrincipalList, aFrame, temp);
   if (NS_FAILED(rv)) {
     return rv;
   }
   if (!aIsFluid) {
     // Split inline ancestor frames
     rv = SplitInlineAncestors(parent, aFrame);
     if (NS_FAILED(rv)) {
       return rv;
     }
   }
   return NS_OK;
 }
 /*
  * Overview of the implementation of Resolve():
  *
  *  Walk through the descendants of aBlockFrame and build:
  *   * mLogicalFrames: an nsTArray of nsIFrame* pointers in logical order
  *   * mBuffer: an nsString containing a representation of
  *     the content of the frames.
  *     In the case of text frames, this is the actual text context of the
  *     frames, but some other elements are represented in a symbolic form which
  *     will make the Unicode Bidi Algorithm give the correct results.
  *     Bidi embeddings and overrides set by CSS or <bdo> elements are
  *     represented by the corresponding Unicode control characters.
  *     <br> elements are represented by U+2028 LINE SEPARATOR
  *     Other inline elements are represented by U+FFFC OBJECT REPLACEMENT
  *     CHARACTER
  *
  *  Then pass mBuffer to the Bidi engine for resolving of embedding levels
  *  by nsBidi::SetPara() and division into directional runs by
  *  nsBidi::CountRuns().
  *
  *  Finally, walk these runs in logical order using nsBidi::GetLogicalRun() and
  *  correlate them with the frames indexed in mLogicalFrames, setting the
  *  baseLevel and embeddingLevel properties according to the results returned
  *  by the Bidi engine.
  *
  *  The rendering layer requires each text frame to contain text in only one
  *  direction, so we may need to call EnsureBidiContinuation() to split frames.
  *  We may also need to call RemoveBidiContinuation() to convert frames created
  *  by EnsureBidiContinuation() in previous reflows into fluid continuations.
  */
 nsresult
 nsBidiPresUtils::Resolve(nsBlockFrame* aBlockFrame)
 {
   BidiParagraphData bpd;
   bpd.Init(aBlockFrame);
   // Handle bidi-override being set on the block itself before calling
   // TraverseFrames.
   const nsStyleTextReset* text = aBlockFrame->StyleTextReset();
   char16_t ch = 0;
   if (text->mUnicodeBidi & NS_STYLE_UNICODE_BIDI_OVERRIDE) {
     const nsStyleVisibility* vis = aBlockFrame->StyleVisibility();
     if (NS_STYLE_DIRECTION_RTL == vis->mDirection) {
       ch = kRLO;
     }
     else if (NS_STYLE_DIRECTION_LTR == vis->mDirection) {
       ch = kLRO;
     }
     if (ch != 0) {
       bpd.PushBidiControl(ch);
     }
   }
   for (nsBlockFrame* block = aBlockFrame; block;
        block = static_cast<nsBlockFrame*>(block->GetNextContinuation())) {
     block->RemoveStateBits(NS_BLOCK_NEEDS_BIDI_RESOLUTION);
     nsBlockInFlowLineIterator lineIter(block, block->begin_lines());
     bpd.ResetForNewBlock();
     TraverseFrames(aBlockFrame, &lineIter, block->GetFirstPrincipalChild(), &bpd);
     // XXX what about overflow lines?
   }
   if (ch != 0) {
     bpd.PopBidiControl();
   }
   BidiParagraphData* subParagraph = bpd.GetSubParagraph();
   if (subParagraph->BufferLength()) {
     ResolveParagraph(aBlockFrame, subParagraph);
     subParagraph->EmptyBuffer();
   }
   return ResolveParagraph(aBlockFrame, &bpd);
 }
 nsresult
 nsBidiPresUtils::ResolveParagraph(nsBlockFrame* aBlockFrame,
                                   BidiParagraphData* aBpd)
 {
   nsPresContext *presContext = aBlockFrame->PresContext();
   if (aBpd->BufferLength() < 1) {
     return NS_OK;
   }
   aBpd->mBuffer.ReplaceChar(kSeparators, kSpace);
   int32_t runCount;
   nsresult rv = aBpd->SetPara();
   NS_ENSURE_SUCCESS(rv, rv);
   uint8_t embeddingLevel = aBpd->GetParaLevel();
   rv = aBpd->CountRuns(&runCount);
   NS_ENSURE_SUCCESS(rv, rv);
   int32_t     runLength      = 0;   // the length of the current run of text
   int32_t     lineOffset     = 0;   // the start of the current run
   int32_t     logicalLimit   = 0;   // the end of the current run + 1
   int32_t     numRun         = -1;
   int32_t     fragmentLength = 0;   // the length of the current text frame
   int32_t     frameIndex     = -1;  // index to the frames in mLogicalFrames
   int32_t     frameCount     = aBpd->FrameCount();
   int32_t     contentOffset  = 0;   // offset of current frame in its content node
   bool        isTextFrame    = false;
   nsIFrame*   frame = nullptr;
   nsIContent* content = nullptr;
   int32_t     contentTextLength = 0;
   FramePropertyTable *propTable = presContext->PropertyTable();
   nsLineBox* currentLine = nullptr;
 #ifdef DEBUG
 #ifdef NOISY_BIDI
   printf("Before Resolve(), aBlockFrame=0x%p, mBuffer='%s', frameCount=%d, runCount=%d\n",
          (void*)aBlockFrame, NS_ConvertUTF16toUTF8(aBpd->mBuffer).get(), frameCount, runCount);
 #ifdef REALLY_NOISY_BIDI
   printf(" block frame tree=:\n");
   aBlockFrame->List(stdout, 0);
 #endif
 #endif
 #endif
   if (runCount == 1 && frameCount == 1 &&
       aBpd->mParagraphDepth == 0 && aBpd->GetDirection() == NSBIDI_LTR &&
       aBpd->GetParaLevel() == 0) {
     // We have a single left-to-right frame in a left-to-right paragraph,
     // without bidi isolation from the surrounding text.
     // Make sure that the embedding level and base level frame properties aren't
     // set (because if they are this frame used to have some other direction,
     // so we can't do this optimization), and we're done.
     nsIFrame* frame = aBpd->FrameAt(0);
     if (frame != NS_BIDI_CONTROL_FRAME &&
         !frame->Properties().Get(nsIFrame::EmbeddingLevelProperty()) &&
         !frame->Properties().Get(nsIFrame::BaseLevelProperty())) {
 #ifdef DEBUG
 #ifdef NOISY_BIDI
       printf("early return for single direction frame %p\n", (void*)frame);
 #endif
 #endif
       frame->AddStateBits(NS_FRAME_IS_BIDI);
       return NS_OK;
     }
   }
   nsIFrame* firstFrame = nullptr;
   nsIFrame* lastFrame = nullptr;
   for (; ;) {
     if (fragmentLength <= 0) {
       // Get the next frame from mLogicalFrames
       if (++frameIndex >= frameCount) {
         break;
       }
       frame = aBpd->FrameAt(frameIndex);
       if (frame == NS_BIDI_CONTROL_FRAME ||
           nsGkAtoms::textFrame != frame->GetType()) {
         /*
          * Any non-text frame corresponds to a single character in the text buffer
          * (a bidi control character, LINE SEPARATOR, or OBJECT SUBSTITUTE)
          */
         isTextFrame = false;
         fragmentLength = 1;
       }
       else {
         if (!firstFrame) {
           firstFrame = frame;
         }
         lastFrame = frame;
         currentLine = aBpd->GetLineForFrameAt(frameIndex);
         content = frame->GetContent();
         if (!content) {
           rv = NS_OK;
           break;
         }
         contentTextLength = content->TextLength();
         if (contentTextLength == 0) {
           frame->AdjustOffsetsForBidi(0, 0);
           // Set the base level and embedding level of the current run even
           // on an empty frame. Otherwise frame reordering will not be correct.
           propTable->Set(frame, nsIFrame::EmbeddingLevelProperty(),
                          NS_INT32_TO_PTR(embeddingLevel));
           propTable->Set(frame, nsIFrame::BaseLevelProperty(),
                          NS_INT32_TO_PTR(aBpd->GetParaLevel()));
           propTable->Set(frame, nsIFrame::ParagraphDepthProperty(),
                          NS_INT32_TO_PTR(aBpd->mParagraphDepth));
           continue;
         }
         int32_t start, end;
         frame->GetOffsets(start, end);
         NS_ASSERTION(!(contentTextLength < end - start),
                      "Frame offsets don't fit in content");
         fragmentLength = std::min(contentTextLength, end - start);
         contentOffset = start;
         isTextFrame = true;
       }
     } // if (fragmentLength <= 0)
     if (runLength <= 0) {
       // Get the next run of text from the Bidi engine
       if (++numRun >= runCount) {
         break;
       }
       lineOffset = logicalLimit;
       if (NS_FAILED(aBpd->GetLogicalRun(
               lineOffset, &logicalLimit, &embeddingLevel) ) ) {
         break;
       }
       runLength = logicalLimit - lineOffset;
     } // if (runLength <= 0)
     if (frame == NS_BIDI_CONTROL_FRAME) {
       frame = nullptr;
       ++lineOffset;
     }
     else {
       propTable->Set(frame, nsIFrame::EmbeddingLevelProperty(),
                      NS_INT32_TO_PTR(embeddingLevel));
       propTable->Set(frame, nsIFrame::BaseLevelProperty(),
                      NS_INT32_TO_PTR(aBpd->GetParaLevel()));
       propTable->Set(frame, nsIFrame::ParagraphDepthProperty(),
                      NS_INT32_TO_PTR(aBpd->mParagraphDepth));
       if (isTextFrame) {
         if ( (runLength > 0) && (runLength < fragmentLength) ) {
           /*
            * The text in this frame continues beyond the end of this directional run.
            * Create a non-fluid continuation frame for the next directional run.
            */
           currentLine->MarkDirty();
           nsIFrame* nextBidi;
           int32_t runEnd = contentOffset + runLength;
           rv = EnsureBidiContinuation(frame, &nextBidi, frameIndex,
                                       contentOffset,
                                       runEnd);
           if (NS_FAILED(rv)) {
             break;
           }
           nextBidi->AdjustOffsetsForBidi(runEnd,
                                          contentOffset + fragmentLength);
           lastFrame = frame = nextBidi;
           contentOffset = runEnd;
         } // if (runLength < fragmentLength)
         else {
           if (contentOffset + fragmentLength == contentTextLength) {
             /*
              * We have finished all the text in this content node. Convert any
              * further non-fluid continuations to fluid continuations and advance
              * frameIndex to the last frame in the content node
              */
             int32_t newIndex = aBpd->GetLastFrameForContent(content);
             if (newIndex > frameIndex) {
               currentLine->MarkDirty();
               RemoveBidiContinuation(aBpd, frame,
                                      frameIndex, newIndex, lineOffset);
               frameIndex = newIndex;
               lastFrame = frame = aBpd->FrameAt(frameIndex);
             }
           } else if (fragmentLength > 0 && runLength > fragmentLength) {
             /*
              * There is more text that belongs to this directional run in the next
              * text frame: make sure it is a fluid continuation of the current frame.
              * Do not advance frameIndex, because the next frame may contain
              * multi-directional text and need to be split
              */
             int32_t newIndex = frameIndex;
             do {
             } while (++newIndex < frameCount &&
                      aBpd->FrameAt(newIndex) == NS_BIDI_CONTROL_FRAME);
             if (newIndex < frameCount) {
               currentLine->MarkDirty();
               RemoveBidiContinuation(aBpd, frame,
                                      frameIndex, newIndex, lineOffset);
             }
           } else if (runLength == fragmentLength) {
             /*
              * If the directional run ends at the end of the frame, make sure
              * that any continuation is non-fluid, and do the same up the
              * parent chain
              */
             nsIFrame* next = frame->GetNextInFlow();
             if (next) {
               currentLine->MarkDirty();
               MakeContinuationsNonFluidUpParentChain(frame, next);
             }
           }
           frame->AdjustOffsetsForBidi(contentOffset, contentOffset + fragmentLength);
           currentLine->MarkDirty();
         }
       } // isTextFrame
       else {
         ++lineOffset;
       }
     } // not bidi control frame
     int32_t temp = runLength;
     runLength -= fragmentLength;
     fragmentLength -= temp;
     if (frame && fragmentLength <= 0) {
       // If the frame is at the end of a run, and this is not the end of our
       // paragrah, split all ancestor inlines that need splitting.
       // To determine whether we're at the end of the run, we check that we've
       // finished processing the current run, and that the current frame
       // doesn't have a fluid continuation (it could have a fluid continuation
       // of zero length, so testing runLength alone is not sufficient).
       if (runLength <= 0 && !frame->GetNextInFlow()) {
         if (numRun + 1 < runCount) {
           nsIFrame* child = frame;
           nsIFrame* parent = frame->GetParent();
           // As long as we're on the last sibling, the parent doesn't have to
           // be split.
           // However, if the parent has a fluid continuation, we do have to make
           // it non-fluid. This can happen e.g. when we have a first-letter
           // frame and the end of the first-letter coincides with the end of a
           // directional run.
           while (parent &&
                  IsBidiSplittable(parent) &&
                  !child->GetNextSibling()) {
             nsIFrame* next = parent->GetNextInFlow();
             if (next) {
               parent->SetNextContinuation(next);
               next->SetPrevContinuation(parent);
             }
             child = parent;
             parent = child->GetParent();
           }
           if (parent && IsBidiSplittable(parent)) {
             SplitInlineAncestors(parent, child);
           }
         }
       }
       else {
         // We're not at an end of a run. If |frame| is the last child of its
         // parent, and its ancestors happen to have bidi continuations, convert
         // them into fluid continuations.
         JoinInlineAncestors(frame);
       }
     }
   } // for
   if (aBpd->mParagraphDepth > 0) {
     nsIFrame* child;
     nsIFrame* parent;
     if (firstFrame) {
       child = firstFrame->GetParent();
       if (child) {
         parent = child->GetParent();
         if (parent && IsBidiSplittable(parent)) {
           nsIFrame* prev = child->GetPrevSibling();
           if (prev) {
             SplitInlineAncestors(parent, prev);
           }
         }
       }
     }
     if (lastFrame) {
       child = lastFrame->GetParent();
       if (child) {
         parent = child->GetParent();
         if (parent && IsBidiSplittable(parent)) {
           SplitInlineAncestors(parent, child);
         }
       }
     }
   }
 #ifdef DEBUG
 #ifdef REALLY_NOISY_BIDI
   printf("---\nAfter Resolve(), frameTree =:\n");
   aBlockFrame->List(stdout, 0);
   printf("===\n");
 #endif
 #endif
   return rv;
 }
 void
 nsBidiPresUtils::TraverseFrames(nsBlockFrame*              aBlockFrame,
                                 nsBlockInFlowLineIterator* aLineIter,
                                 nsIFrame*                  aCurrentFrame,
                                 BidiParagraphData*         aBpd)
 {
   if (!aCurrentFrame)
     return;
 #ifdef DEBUG
   nsBlockFrame* initialLineContainer = aLineIter->GetContainer();
 #endif
   nsIFrame* childFrame = aCurrentFrame;
   do {
     /*
      * It's important to get the next sibling and next continuation *before*
      * handling the frame: If we encounter a forced paragraph break and call
      * ResolveParagraph within this loop, doing GetNextSibling and
      * GetNextContinuation after that could return a bidi continuation that had
      * just been split from the original childFrame and we would process it
      * twice.
      */
     nsIFrame* nextSibling = childFrame->GetNextSibling();
     bool isLastFrame = !childFrame->GetNextContinuation();
     bool isFirstFrame = !childFrame->GetPrevContinuation();
     // If the real frame for a placeholder is a first letter frame, we need to
     // drill down into it and include its contents in Bidi resolution.
     // If not, we just use the placeholder.
     nsIFrame* frame = childFrame;
     if (nsGkAtoms::placeholderFrame == childFrame->GetType()) {
       nsIFrame* realFrame =
         nsPlaceholderFrame::GetRealFrameForPlaceholder(childFrame);
       if (realFrame->GetType() == nsGkAtoms::letterFrame) {
         frame = realFrame;
       }
     }
     char16_t ch = 0;
     if (frame->IsFrameOfType(nsIFrame::eBidiInlineContainer)) {
       if (!(frame->GetStateBits() & NS_FRAME_FIRST_REFLOW)) {
         nsContainerFrame* c = static_cast<nsContainerFrame*>(frame);
         MOZ_ASSERT(c = do_QueryFrame(frame),
                    "eBidiInlineContainer must be a nsContainerFrame subclass");
         c->DrainSelfOverflowList();
       }
       const nsStyleVisibility* vis = frame->StyleVisibility();
       const nsStyleTextReset* text = frame->StyleTextReset();
       if (text->mUnicodeBidi & NS_STYLE_UNICODE_BIDI_OVERRIDE) {
         if (NS_STYLE_DIRECTION_RTL == vis->mDirection) {
           ch = kRLO;
         }
         else if (NS_STYLE_DIRECTION_LTR == vis->mDirection) {
           ch = kLRO;
         }
       } else if (text->mUnicodeBidi & NS_STYLE_UNICODE_BIDI_EMBED) {
         if (NS_STYLE_DIRECTION_RTL == vis->mDirection) {
           ch = kRLE;
         }
         else if (NS_STYLE_DIRECTION_LTR == vis->mDirection) {
           ch = kLRE;
         }
       }
       // Add a dummy frame pointer representing a bidi control code before the
       // first frame of an element specifying embedding or override
       if (ch != 0 && isFirstFrame) {
         aBpd->PushBidiControl(ch);
       }
     }
     if (IsBidiLeaf(frame)) {
       /* Bidi leaf frame: add the frame to the mLogicalFrames array,
        * and add its index to the mContentToFrameIndex hashtable. This
        * will be used in RemoveBidiContinuation() to identify the last
        * frame in the array with a given content.
        */
       nsIContent* content = frame->GetContent();
       aBpd->AppendFrame(frame, aLineIter, content);
       // Append the content of the frame to the paragraph buffer
       nsIAtom* frameType = frame->GetType();
       if (nsGkAtoms::textFrame == frameType) {
         if (content != aBpd->mPrevContent) {
           aBpd->mPrevContent = content;
           if (!frame->StyleText()->NewlineIsSignificant()) {
             content->AppendTextTo(aBpd->mBuffer);
           } else {
             /*
              * For preformatted text we have to do bidi resolution on each line
              * separately.
              */
             nsAutoString text;
             content->AppendTextTo(text);
             nsIFrame* next;
             do {
               next = nullptr;
               int32_t start, end;
               frame->GetOffsets(start, end);
               int32_t endLine = text.FindChar('\n', start);
               if (endLine == -1) {
                 /*
                  * If there is no newline in the text content, just save the
                  * text from this frame and its continuations, and do bidi
                  * resolution later
                  */
                 aBpd->AppendString(Substring(text, start));
                 while (frame && nextSibling) {
                   aBpd->AdvanceAndAppendFrame(&frame, aLineIter, &nextSibling);
                 }
                 break;
               }
               /*
                * If there is a newline in the frame, break the frame after the
                * newline, do bidi resolution and repeat until the last sibling
                */
               ++endLine;
               /*
                * If the frame ends before the new line, save the text and move
                * into the next continuation
                */
               aBpd->AppendString(Substring(text, start,
                                            std::min(end, endLine) - start));
               while (end < endLine && nextSibling) {
                 aBpd->AdvanceAndAppendFrame(&frame, aLineIter, &nextSibling);
                 NS_ASSERTION(frame, "Premature end of continuation chain");
                 frame->GetOffsets(start, end);
                 aBpd->AppendString(Substring(text, start,
                                              std::min(end, endLine) - start));
               }
               if (end < endLine) {
                 aBpd->mPrevContent = nullptr;
                 break;
               }
               bool createdContinuation = false;
               if (uint32_t(endLine) < text.Length()) {
                 /*
                  * Timing is everything here: if the frame already has a bidi
                  * continuation, we need to make the continuation fluid *before*
                  * resetting the length of the current frame. Otherwise
                  * nsTextFrame::SetLength won't set the continuation frame's
                  * text offsets correctly.
                  *
                  * On the other hand, if the frame doesn't have a continuation,
                  * we need to create one *after* resetting the length, or
                  * CreateContinuingFrame will complain that there is no more
                  * content for the continuation.
                  */
                 next = frame->GetNextInFlow();
                 if (!next) {
                   // If the frame already has a bidi continuation, make it fluid
                   next = frame->GetNextContinuation();
                   if (next) {
                     MakeContinuationFluid(frame, next);
                     JoinInlineAncestors(frame);
                   }
                 }
                 nsTextFrame* textFrame = static_cast<nsTextFrame*>(frame);
                 textFrame->SetLength(endLine - start, nullptr);
                 if (!next) {
                   // If the frame has no next in flow, create one.
                   CreateContinuation(frame, &next, true);
                   createdContinuation = true;
                 }
                 aBpd->GetLineForFrameAt(aBpd->FrameCount() - 1)->MarkDirty();
               }
               ResolveParagraphWithinBlock(aBlockFrame, aBpd);
               if (!nextSibling && !createdContinuation) {
                 break;
               } else if (next) {
                 frame = next;
                 aBpd->AppendFrame(frame, aLineIter);
               }
               /*
                * If we have already overshot the saved next-sibling while
                * scanning the frame's continuations, advance it.
                */
               if (frame && frame == nextSibling) {
                 nextSibling = frame->GetNextSibling();
               }
             } while (next);
           }
         }
       } else if (nsGkAtoms::brFrame == frameType) {
         // break frame -- append line separator
         aBpd->AppendUnichar(kLineSeparator);
         ResolveParagraphWithinBlock(aBlockFrame, aBpd);
       } else {
         // other frame type -- see the Unicode Bidi Algorithm:
         // "...inline objects (such as graphics) are treated as if they are ...
         // U+FFFC"
         // <wbr>, however, is treated as U+200B ZERO WIDTH SPACE. See
         // http://dev.w3.org/html5/spec/Overview.html#phrasing-content-1
         aBpd->AppendUnichar(content->IsHTML(nsGkAtoms::wbr) ?
                             kZWSP : kObjectSubstitute);
         if (!frame->IsInlineOutside()) {
           // if it is not inline, end the paragraph
           ResolveParagraphWithinBlock(aBlockFrame, aBpd);
         }
       }
     } else {
       // For a non-leaf frame, recurse into TraverseFrames
       nsIFrame* kid = frame->GetFirstPrincipalChild();
       MOZ_ASSERT(!frame->GetFirstChild(nsIFrame::kOverflowList),
                  "should have drained the overflow list above");
       if (kid) {
         const nsStyleTextReset* text = frame->StyleTextReset();
         if (text->mUnicodeBidi & NS_STYLE_UNICODE_BIDI_ISOLATE ||
             text->mUnicodeBidi & NS_STYLE_UNICODE_BIDI_PLAINTEXT) {
           // css "unicode-bidi: isolate" and html5 bdi:
           //  resolve the element as a separate paragraph
           BidiParagraphData* subParagraph = aBpd->GetSubParagraph();
           /*
            * As at the beginning of the loop, it's important to check for
            * next-continuations before handling the frame. If we do
            * TraverseFrames and *then* do GetNextContinuation on the original
            * first frame, it could return a bidi continuation that had only
            * just been created, and we would skip doing bidi resolution on the
            * last part of the sub-paragraph.
            */
           bool isLastContinuation = !frame->GetNextContinuation();
           if (!frame->GetPrevContinuation() || !subParagraph->mReset) {
             if (subParagraph->BufferLength()) {
               ResolveParagraph(aBlockFrame, subParagraph);
             }
             subParagraph->Reset(frame, aBpd);
           }
           TraverseFrames(aBlockFrame, aLineIter, kid, subParagraph);
           if (isLastContinuation) {
             ResolveParagraph(aBlockFrame, subParagraph);
             subParagraph->EmptyBuffer();
           }
           // Treat the element as a neutral character within its containing
           //  paragraph.
           aBpd->AppendControlChar(kObjectSubstitute);
         } else {
           TraverseFrames(aBlockFrame, aLineIter, kid, aBpd);
         }
       }
     }
     // If the element is attributed by dir, indicate direction pop (add PDF frame)
     if (isLastFrame) {
       if (ch) {
         // Add a dummy frame pointer representing a bidi control code after the
         // last frame of an element specifying embedding or override
         aBpd->PopBidiControl();
       }
     }
     childFrame = nextSibling;
   } while (childFrame);
   MOZ_ASSERT(initialLineContainer == aLineIter->GetContainer());
 }
 void
 nsBidiPresUtils::ResolveParagraphWithinBlock(nsBlockFrame* aBlockFrame,
                                              BidiParagraphData* aBpd)
 {
   aBpd->ClearBidiControls();
   ResolveParagraph(aBlockFrame, aBpd);
   aBpd->ResetData();
 }
 void
 nsBidiPresUtils::ReorderFrames(nsIFrame*   aFirstFrameOnLine,
                                int32_t     aNumFramesOnLine,
                                WritingMode aLineWM,
                                nscoord&    aLineWidth)
 {
   // If this line consists of a line frame, reorder the line frame's children.
   if (aFirstFrameOnLine->GetType() == nsGkAtoms::lineFrame) {
     aFirstFrameOnLine = aFirstFrameOnLine->GetFirstPrincipalChild();
     if (!aFirstFrameOnLine)
       return;
     // All children of the line frame are on the first line. Setting aNumFramesOnLine
     // to -1 makes InitLogicalArrayFromLine look at all of them.
     aNumFramesOnLine = -1;
   }
   BidiLineData bld(aFirstFrameOnLine, aNumFramesOnLine);
   RepositionInlineFrames(&bld, aFirstFrameOnLine, aLineWM, aLineWidth);
 }
 nsIFrame*
 nsBidiPresUtils::GetFirstLeaf(nsIFrame* aFrame)
 {
   nsIFrame* firstLeaf = aFrame;
   while (!IsBidiLeaf(firstLeaf)) {
     nsIFrame* firstChild = firstLeaf->GetFirstPrincipalChild();
     nsIFrame* realFrame = nsPlaceholderFrame::GetRealFrameFor(firstChild);
     firstLeaf = (realFrame->GetType() == nsGkAtoms::letterFrame) ?
                  realFrame : firstChild;
   }
   return firstLeaf;
 }
 nsBidiLevel
 nsBidiPresUtils::GetFrameEmbeddingLevel(nsIFrame* aFrame)
 {
   return NS_GET_EMBEDDING_LEVEL(nsBidiPresUtils::GetFirstLeaf(aFrame));
 }
 uint8_t
 nsBidiPresUtils::GetParagraphDepth(nsIFrame* aFrame)
 {
   return NS_GET_PARAGRAPH_DEPTH(nsBidiPresUtils::GetFirstLeaf(aFrame));
 }
 nsBidiLevel
 nsBidiPresUtils::GetFrameBaseLevel(nsIFrame* aFrame)
 {
   nsIFrame* firstLeaf = aFrame;
   while (!IsBidiLeaf(firstLeaf)) {
     firstLeaf = firstLeaf->GetFirstPrincipalChild();
   }
   return NS_GET_BASE_LEVEL(firstLeaf);
 }
 void
 nsBidiPresUtils::IsFirstOrLast(nsIFrame*             aFrame,
                                nsContinuationStates* aContinuationStates,
                                bool&                 aIsFirst /* out */,
                                bool&                 aIsLast /* out */)
 {
   /*
    * Since we lay out frames in the line's direction, visiting a frame with
    * 'mFirstVisualFrame == nullptr', means it's the first appearance of one
    * of its continuation chain frames on the line.
    * To determine if it's the last visual frame of its continuation chain on
    * the line or not, we count the number of frames of the chain on the line,
    * and then reduce it when we lay out a frame of the chain. If this value
    * becomes 1 it means that it's the last visual frame of its continuation
    * chain on this line.
    */
   nsFrameContinuationState* frameState = aContinuationStates->GetEntry(aFrame);
   nsFrameContinuationState* firstFrameState;
   if (!frameState->mFirstVisualFrame) {
     // aFrame is the first visual frame of its continuation chain
     nsFrameContinuationState* contState;
     nsIFrame* frame;
     frameState->mFrameCount = 1;
     frameState->mFirstVisualFrame = aFrame;
     /**
      * Traverse continuation chain of aFrame in both backward and forward
      * directions while the frames are on this line. Count the frames and
      * set their mFirstVisualFrame to aFrame.
      */
     // Traverse continuation chain backward
     for (frame = aFrame->GetPrevContinuation();
          frame && (contState = aContinuationStates->GetEntry(frame));
          frame = frame->GetPrevContinuation()) {
       frameState->mFrameCount++;
       contState->mFirstVisualFrame = aFrame;
     }
     frameState->mHasContOnPrevLines = (frame != nullptr);
     // Traverse continuation chain forward
     for (frame = aFrame->GetNextContinuation();
          frame && (contState = aContinuationStates->GetEntry(frame));
          frame = frame->GetNextContinuation()) {
       frameState->mFrameCount++;
       contState->mFirstVisualFrame = aFrame;
     }
     frameState->mHasContOnNextLines = (frame != nullptr);
     aIsFirst = !frameState->mHasContOnPrevLines;
     firstFrameState = frameState;
   } else {
     // aFrame is not the first visual frame of its continuation chain
     aIsFirst = false;
     firstFrameState = aContinuationStates->GetEntry(frameState->mFirstVisualFrame);
   }
   aIsLast = (firstFrameState->mFrameCount == 1 &&
              !firstFrameState->mHasContOnNextLines);
   if ((aIsFirst || aIsLast) &&
       (aFrame->GetStateBits() & NS_FRAME_PART_OF_IBSPLIT)) {
     // For ib splits, don't treat anything except the last part as
     // endmost or anything except the first part as startmost.
     // As an optimization, only get the first continuation once.
     nsIFrame* firstContinuation = aFrame->FirstContinuation();
     if (firstContinuation->FrameIsNonLastInIBSplit()) {
       // We are not endmost
       aIsLast = false;
     }
     if (firstContinuation->FrameIsNonFirstInIBSplit()) {
       // We are not startmost
       aIsFirst = false;
     }
   }
   // Reduce number of remaining frames of the continuation chain on the line.
   firstFrameState->mFrameCount--;
 }
 void
 nsBidiPresUtils::RepositionFrame(nsIFrame*             aFrame,
                                  bool                  aIsEvenLevel,
                                  nscoord&              aStart,
                                  nsContinuationStates* aContinuationStates,
                                  WritingMode           aLineWM,
                                  nscoord&              aLineWidth)
 {
   if (!aFrame)
     return;
   bool isFirst, isLast;
   IsFirstOrLast(aFrame,
                 aContinuationStates,
                 isFirst /* out */,
                 isLast /* out */);
   WritingMode frameWM = aFrame->GetWritingMode();
   nsInlineFrame* testFrame = do_QueryFrame(aFrame);
   if (testFrame) {
     aFrame->AddStateBits(NS_INLINE_FRAME_BIDI_VISUAL_STATE_IS_SET);
     if (isFirst) {
       aFrame->AddStateBits(NS_INLINE_FRAME_BIDI_VISUAL_IS_FIRST);
     } else {
       aFrame->RemoveStateBits(NS_INLINE_FRAME_BIDI_VISUAL_IS_FIRST);
     }
     if (isLast) {
       aFrame->AddStateBits(NS_INLINE_FRAME_BIDI_VISUAL_IS_LAST);
     } else {
       aFrame->RemoveStateBits(NS_INLINE_FRAME_BIDI_VISUAL_IS_LAST);
     }
   }
   // This method is called from nsBlockFrame::PlaceLine via the call to
   // bidiUtils->ReorderFrames, so this is guaranteed to be after the inlines
   // have been reflowed, which is required for GetUsedMargin/Border/Padding
   LogicalMargin margin(frameWM, aFrame->GetUsedMargin());
   if (isFirst) {
     aStart += margin.IStart(frameWM);
   }
   nscoord start = aStart;
   nscoord frameWidth = aFrame->GetSize().width;
   if (!IsBidiLeaf(aFrame))
   {
     nscoord iCoord = 0;
     LogicalMargin borderPadding(frameWM, aFrame->GetUsedBorderAndPadding());
     if (isFirst) {
       iCoord += borderPadding.IStart(frameWM);
     }
     // If the resolved direction of the container is different from the
     // direction of the frame, we need to traverse the child list in reverse
     // order, to make it O(n) we store the list locally and iterate the list
     // in reverse
     bool reverseOrder = aIsEvenLevel != frameWM.IsBidiLTR();
     nsTArray<nsIFrame*> childList;
     nsIFrame *frame = aFrame->GetFirstPrincipalChild();
     if (frame && reverseOrder) {
       childList.AppendElement((nsIFrame*)nullptr);
       while (frame) {
         childList.AppendElement(frame);
         frame = frame->GetNextSibling();
       }
       frame = childList[childList.Length() - 1];
     }
     // Reposition the child frames
     int32_t index = 0;
     while (frame) {
       RepositionFrame(frame,
                       aIsEvenLevel,
                       iCoord,
                       aContinuationStates,
                       frameWM,
                       frameWidth);
       index++;
       frame = reverseOrder ?
                 childList[childList.Length() - index - 1] :
                 frame->GetNextSibling();
     }
     if (isLast) {
       iCoord += borderPadding.IEnd(frameWM);
     }
     aStart += iCoord;
   } else {
     aStart += frameWidth;
   }
   LogicalRect logicalRect(aLineWM, aFrame->GetRect(), aLineWidth);
   logicalRect.IStart(aLineWM) = start;
   logicalRect.ISize(aLineWM) = aStart - start;
   aFrame->SetRect(aLineWM, logicalRect, aLineWidth);
   if (isLast) {
     aStart += margin.IEnd(frameWM);
   }
 }
 void
 nsBidiPresUtils::InitContinuationStates(nsIFrame*              aFrame,
                                         nsContinuationStates*  aContinuationStates)
 {
   nsFrameContinuationState* state = aContinuationStates->PutEntry(aFrame);
   state->mFirstVisualFrame = nullptr;
   state->mFrameCount = 0;
   if (!IsBidiLeaf(aFrame)) {
     // Continue for child frames
     nsIFrame* frame;
     for (frame = aFrame->GetFirstPrincipalChild();
          frame;
          frame = frame->GetNextSibling()) {
       InitContinuationStates(frame,
                              aContinuationStates);
     }
   }
 }
 void
 nsBidiPresUtils::RepositionInlineFrames(BidiLineData *aBld,
                                         nsIFrame* aFirstChild,
                                         WritingMode aLineWM,
                                         nscoord& aLineWidth)
 {
   nscoord startSpace = 0;
   // This method is called from nsBlockFrame::PlaceLine via the call to
   // bidiUtils->ReorderFrames, so this is guaranteed to be after the inlines
   // have been reflowed, which is required for GetUsedMargin/Border/Padding
   WritingMode frameWM = aFirstChild->GetWritingMode();
   LogicalMargin margin(frameWM, aFirstChild->GetUsedMargin());
   if (!aFirstChild->GetPrevContinuation() &&
       !aFirstChild->FrameIsNonFirstInIBSplit())
     startSpace = margin.IStart(frameWM);
   nscoord start = LogicalRect(aLineWM, aFirstChild->GetRect(),
                               aLineWidth).IStart(aLineWM) - startSpace;
   nsIFrame* frame;
   int32_t count = aBld->mVisualFrames.Length();
   int32_t index;
   nsContinuationStates continuationStates;
   // Initialize continuation states to (nullptr, 0) for
   // each frame on the line.
   for (index = 0; index < count; index++) {
     InitContinuationStates(aBld->VisualFrameAt(index), &continuationStates);
   }
   // Reposition frames in visual order
   int32_t step, limit;
   if (aLineWM.IsBidiLTR()) {
     index = 0;
     step = 1;
     limit = count;
   } else {
     index = count - 1;
     step = -1;
     limit = -1;
   }
   for (; index != limit; index += step) {
     frame = aBld->VisualFrameAt(index);
     RepositionFrame(frame,
                     !(aBld->mLevels[aBld->mIndexMap[index]] & 1),
                     start,
                     &continuationStates,
                     aLineWM,
                     aLineWidth);
   }
 }
 bool
 nsBidiPresUtils::CheckLineOrder(nsIFrame*  aFirstFrameOnLine,
                                 int32_t    aNumFramesOnLine,
                                 nsIFrame** aFirstVisual,
                                 nsIFrame** aLastVisual)
 {
   BidiLineData bld(aFirstFrameOnLine, aNumFramesOnLine);
   int32_t count = bld.FrameCount();
   if (aFirstVisual) {
     *aFirstVisual = bld.VisualFrameAt(0);
   }
   if (aLastVisual) {
     *aLastVisual = bld.VisualFrameAt(count-1);
   }
   return bld.mIsReordered;
 }
 nsIFrame*
 nsBidiPresUtils::GetFrameToRightOf(const nsIFrame*  aFrame,
                                    nsIFrame*        aFirstFrameOnLine,
                                    int32_t          aNumFramesOnLine)
 {
   BidiLineData bld(aFirstFrameOnLine, aNumFramesOnLine);
   int32_t count = bld.mVisualFrames.Length();
   if (aFrame == nullptr && count)
     return bld.VisualFrameAt(0);
   for (int32_t i = 0; i < count - 1; i++) {
     if (bld.VisualFrameAt(i) == aFrame) {
       return bld.VisualFrameAt(i+1);
     }
   }
   return nullptr;
 }
 nsIFrame*
 nsBidiPresUtils::GetFrameToLeftOf(const nsIFrame*  aFrame,
                                   nsIFrame*        aFirstFrameOnLine,
                                   int32_t          aNumFramesOnLine)
 {
   BidiLineData bld(aFirstFrameOnLine, aNumFramesOnLine);
   int32_t count = bld.mVisualFrames.Length();
   if (aFrame == nullptr && count)
     return bld.VisualFrameAt(count-1);
   for (int32_t i = 1; i < count; i++) {
     if (bld.VisualFrameAt(i) == aFrame) {
       return bld.VisualFrameAt(i-1);
     }
   }
   return nullptr;
 }
 inline nsresult
 nsBidiPresUtils::EnsureBidiContinuation(nsIFrame*       aFrame,
                                         nsIFrame**      aNewFrame,
                                         int32_t&        aFrameIndex,
                                         int32_t         aStart,
                                         int32_t         aEnd)
 {
   NS_PRECONDITION(aNewFrame, "null OUT ptr");
   NS_PRECONDITION(aFrame, "aFrame is null");
   aFrame->AdjustOffsetsForBidi(aStart, aEnd);
   return CreateContinuation(aFrame, aNewFrame, false);
 }
 void
 nsBidiPresUtils::RemoveBidiContinuation(BidiParagraphData *aBpd,
                                         nsIFrame*       aFrame,
                                         int32_t         aFirstIndex,
                                         int32_t         aLastIndex,
                                         int32_t&        aOffset)
 {
   FrameProperties props = aFrame->Properties();
   nsBidiLevel embeddingLevel =
     (nsBidiLevel)NS_PTR_TO_INT32(props.Get(nsIFrame::EmbeddingLevelProperty()));
   nsBidiLevel baseLevel =
     (nsBidiLevel)NS_PTR_TO_INT32(props.Get(nsIFrame::BaseLevelProperty()));
   uint8_t paragraphDepth =
     NS_PTR_TO_INT32(props.Get(nsIFrame::ParagraphDepthProperty()));
   for (int32_t index = aFirstIndex + 1; index <= aLastIndex; index++) {
     nsIFrame* frame = aBpd->FrameAt(index);
     if (frame == NS_BIDI_CONTROL_FRAME) {
       ++aOffset;
     }
     else {
       // Make the frame and its continuation ancestors fluid,
       // so they can be reused or deleted by normal reflow code
       FrameProperties frameProps = frame->Properties();
       frameProps.Set(nsIFrame::EmbeddingLevelProperty(),
                      NS_INT32_TO_PTR(embeddingLevel));
       frameProps.Set(nsIFrame::BaseLevelProperty(),
                      NS_INT32_TO_PTR(baseLevel));
       frameProps.Set(nsIFrame::ParagraphDepthProperty(),
                      NS_INT32_TO_PTR(paragraphDepth));
       frame->AddStateBits(NS_FRAME_IS_BIDI);
       while (frame) {
         nsIFrame* prev = frame->GetPrevContinuation();
         if (prev) {
           MakeContinuationFluid(prev, frame);
           frame = frame->GetParent();
         } else {
           break;
         }
       }
     }
   }
   // Make sure that the last continuation we made fluid does not itself have a
   // fluid continuation (this can happen when re-resolving after dynamic changes
   // to content)
   nsIFrame* lastFrame = aBpd->FrameAt(aLastIndex);
   MakeContinuationsNonFluidUpParentChain(lastFrame, lastFrame->GetNextInFlow());
 }
 nsresult
 nsBidiPresUtils::FormatUnicodeText(nsPresContext*  aPresContext,
                                    char16_t*       aText,
                                    int32_t&         aTextLength,
                                    nsCharType       aCharType,
                                    bool             aIsOddLevel)
 {
   nsresult rv = NS_OK;
   // ahmed
   //adjusted for correct numeral shaping
   uint32_t bidiOptions = aPresContext->GetBidi();
   switch (GET_BIDI_OPTION_NUMERAL(bidiOptions)) {
     case IBMBIDI_NUMERAL_HINDI:
       HandleNumbers(aText,aTextLength,IBMBIDI_NUMERAL_HINDI);
       break;
     case IBMBIDI_NUMERAL_ARABIC:
       HandleNumbers(aText,aTextLength,IBMBIDI_NUMERAL_ARABIC);
       break;
     case IBMBIDI_NUMERAL_PERSIAN:
       HandleNumbers(aText,aTextLength,IBMBIDI_NUMERAL_PERSIAN);
       break;
     case IBMBIDI_NUMERAL_REGULAR:
       switch (aCharType) {
         case eCharType_EuropeanNumber:
           HandleNumbers(aText,aTextLength,IBMBIDI_NUMERAL_ARABIC);
           break;
         case eCharType_ArabicNumber:
           HandleNumbers(aText,aTextLength,IBMBIDI_NUMERAL_HINDI);
           break;
         default:
           break;
       }
       break;
     case IBMBIDI_NUMERAL_HINDICONTEXT:
       if ( ( (GET_BIDI_OPTION_DIRECTION(bidiOptions)==IBMBIDI_TEXTDIRECTION_RTL) && (IS_ARABIC_DIGIT (aText[0])) ) || (eCharType_ArabicNumber == aCharType) )
         HandleNumbers(aText,aTextLength,IBMBIDI_NUMERAL_HINDI);
       else if (eCharType_EuropeanNumber == aCharType)
         HandleNumbers(aText,aTextLength,IBMBIDI_NUMERAL_ARABIC);
       break;
     case IBMBIDI_NUMERAL_PERSIANCONTEXT:
       if ( ( (GET_BIDI_OPTION_DIRECTION(bidiOptions)==IBMBIDI_TEXTDIRECTION_RTL) && (IS_ARABIC_DIGIT (aText[0])) ) || (eCharType_ArabicNumber == aCharType) )
         HandleNumbers(aText,aTextLength,IBMBIDI_NUMERAL_PERSIAN);
       else if (eCharType_EuropeanNumber == aCharType)
         HandleNumbers(aText,aTextLength,IBMBIDI_NUMERAL_ARABIC);
       break;
     case IBMBIDI_NUMERAL_NOMINAL:
     default:
       break;
   }
   StripBidiControlCharacters(aText, aTextLength);
   return rv;
 }
 void
 nsBidiPresUtils::StripBidiControlCharacters(char16_t* aText,
                                             int32_t&   aTextLength)
 {
   if ( (nullptr == aText) || (aTextLength < 1) ) {
     return;
   }
   int32_t stripLen = 0;
   for (int32_t i = 0; i < aTextLength; i++) {
     // XXX: This silently ignores surrogate characters.
     //      As of Unicode 4.0, all Bidi control characters are within the BMP.
     if (IsBidiControl((uint32_t)aText[i])) {
       ++stripLen;
     }
     else {
       aText[i - stripLen] = aText[i];
     }
   }
   aTextLength -= stripLen;
 }
 #if 0 // XXX: for the future use ???
 void
 RemoveDiacritics(char16_t* aText,
                  int32_t&   aTextLength)
 {
   if (aText && (aTextLength > 0) ) {
     int32_t offset = 0;
     for (int32_t i = 0; i < aTextLength && aText[i]; i++) {
       if (IS_BIDI_DIACRITIC(aText[i]) ) {
         ++offset;
         continue;
       }
       aText[i - offset] = aText[i];
     }
     aTextLength = i - offset;
     aText[aTextLength] = 0;
   }
 }
 #endif
 void
 nsBidiPresUtils::CalculateCharType(nsBidi* aBidiEngine,
                                    const char16_t* aText,
                                    int32_t& aOffset,
                                    int32_t  aCharTypeLimit,
                                    int32_t& aRunLimit,
                                    int32_t& aRunLength,
                                    int32_t& aRunCount,
                                    uint8_t& aCharType,
                                    uint8_t& aPrevCharType)
 {
   bool       strongTypeFound = false;
   int32_t    offset;
   nsCharType charType;
   aCharType = eCharType_OtherNeutral;
   for (offset = aOffset; offset < aCharTypeLimit; offset++) {
     // Make sure we give RTL chartype to all characters that would be classified
     // as Right-To-Left by a bidi platform.
     // (May differ from the UnicodeData, eg we set RTL chartype to some NSMs.)
     if (IS_HEBREW_CHAR(aText[offset]) ) {
       charType = eCharType_RightToLeft;
     }
     else if (IS_ARABIC_ALPHABETIC(aText[offset]) ) {
       charType = eCharType_RightToLeftArabic;
     }
     else {
       aBidiEngine->GetCharTypeAt(offset, &charType);
     }
     if (!CHARTYPE_IS_WEAK(charType) ) {
       if (strongTypeFound
           && (charType != aPrevCharType)
           && (CHARTYPE_IS_RTL(charType) || CHARTYPE_IS_RTL(aPrevCharType) ) ) {
         // Stop at this point to ensure uni-directionality of the text
         // (from platform's point of view).
         // Also, don't mix Arabic and Hebrew content (since platform may
         // provide BIDI support to one of them only).
         aRunLength = offset - aOffset;
         aRunLimit = offset;
         ++aRunCount;
         break;
       }
       if ( (eCharType_RightToLeftArabic == aPrevCharType
             || eCharType_ArabicNumber == aPrevCharType)
           && eCharType_EuropeanNumber == charType) {
         charType = eCharType_ArabicNumber;
       }
       // Set PrevCharType to the last strong type in this frame
       // (for correct numeric shaping)
       aPrevCharType = charType;
       strongTypeFound = true;
       aCharType = charType;
     }
   }
   aOffset = offset;
 }
 nsresult nsBidiPresUtils::ProcessText(const char16_t*       aText,
                                       int32_t                aLength,
                                       nsBidiLevel            aBaseLevel,
                                       nsPresContext*         aPresContext,
                                       BidiProcessor&         aprocessor,
                                       Mode                   aMode,
                                       nsBidiPositionResolve* aPosResolve,
                                       int32_t                aPosResolveCount,
                                       nscoord*               aWidth,
                                       nsBidi*                aBidiEngine)
 {
   NS_ASSERTION((aPosResolve == nullptr) != (aPosResolveCount > 0), "Incorrect aPosResolve / aPosResolveCount arguments");
   int32_t runCount;
   nsAutoString textBuffer(aText, aLength);
   nsresult rv = aBidiEngine->SetPara(aText, aLength, aBaseLevel, nullptr);
   if (NS_FAILED(rv))
     return rv;
   rv = aBidiEngine->CountRuns(&runCount);
   if (NS_FAILED(rv))
     return rv;
   nscoord xOffset = 0;
   nscoord width, xEndRun = 0;
   nscoord totalWidth = 0;
   int32_t i, start, limit, length;
   uint32_t visualStart = 0;
   uint8_t charType;
   uint8_t prevType = eCharType_LeftToRight;
   nsBidiLevel level;
   for(int nPosResolve=0; nPosResolve < aPosResolveCount; ++nPosResolve)
   {
     aPosResolve[nPosResolve].visualIndex = kNotFound;
     aPosResolve[nPosResolve].visualLeftTwips = kNotFound;
     aPosResolve[nPosResolve].visualWidth = kNotFound;
   }
   for (i = 0; i < runCount; i++) {
     nsBidiDirection dir;
     rv = aBidiEngine->GetVisualRun(i, &start, &length, &dir);
     if (NS_FAILED(rv))
       return rv;
     rv = aBidiEngine->GetLogicalRun(start, &limit, &level);
     if (NS_FAILED(rv))
       return rv;
     int32_t subRunLength = limit - start;
     int32_t lineOffset = start;
     int32_t typeLimit = std::min(limit, aLength);
     int32_t subRunCount = 1;
     int32_t subRunLimit = typeLimit;
     /*
      * If |level| is even, i.e. the direction of the run is left-to-right, we
      * render the subruns from left to right and increment the x-coordinate
      * |xOffset| by the width of each subrun after rendering.
      *
      * If |level| is odd, i.e. the direction of the run is right-to-left, we
      * render the subruns from right to left. We begin by incrementing |xOffset| by
      * the width of the whole run, and then decrement it by the width of each
      * subrun before rendering. After rendering all the subruns, we restore the
      * x-coordinate of the end of the run for the start of the next run.
      */
     if (level & 1) {
       aprocessor.SetText(aText + start, subRunLength, nsBidiDirection(level & 1));
       width = aprocessor.GetWidth();
       xOffset += width;
       xEndRun = xOffset;
     }
     while (subRunCount > 0) {
       // CalculateCharType can increment subRunCount if the run
       // contains mixed character types
       CalculateCharType(aBidiEngine, aText, lineOffset, typeLimit, subRunLimit, subRunLength, subRunCount, charType, prevType);
       nsAutoString runVisualText;
       runVisualText.Assign(aText + start, subRunLength);
       if (int32_t(runVisualText.Length()) < subRunLength)
         return NS_ERROR_OUT_OF_MEMORY;
       FormatUnicodeText(aPresContext, runVisualText.BeginWriting(), subRunLength,
                         (nsCharType)charType, level & 1);
       aprocessor.SetText(runVisualText.get(), subRunLength, nsBidiDirection(level & 1));
       width = aprocessor.GetWidth();
       totalWidth += width;
       if (level & 1) {
         xOffset -= width;
       }
       if (aMode == MODE_DRAW) {
         aprocessor.DrawText(xOffset, width);
       }
       /*
        * The caller may request to calculate the visual position of one
        * or more characters.
        */
       for(int nPosResolve=0; nPosResolve<aPosResolveCount; ++nPosResolve)
       {
         nsBidiPositionResolve* posResolve = &aPosResolve[nPosResolve];
         /*
          * Did we already resolve this position's visual metric? If so, skip.
          */
         if (posResolve->visualLeftTwips != kNotFound)
            continue;
         /*
          * First find out if the logical position is within this run.
          */
         if (start <= posResolve->logicalIndex &&
             start + subRunLength > posResolve->logicalIndex) {
           /*
            * If this run is only one character long, we have an easy case:
            * the visual position is the x-coord of the start of the run
            * less the x-coord of the start of the whole text.
            */
           if (subRunLength == 1) {
             posResolve->visualIndex = visualStart;
             posResolve->visualLeftTwips = xOffset;
             posResolve->visualWidth = width;
           }
           /*
            * Otherwise, we need to measure the width of the run's part
            * which is to the visual left of the index.
            * In other words, the run is broken in two, around the logical index,
            * and we measure the part which is visually left.
            * If the run is right-to-left, this part will span from after the index
            * up to the end of the run; if it is left-to-right, this part will span
            * from the start of the run up to (and inclduing) the character before the index.
            */
           else {
             /*
              * Here is a description of how the width of the current character
              * (posResolve->visualWidth) is calculated:
              *
              * LTR (current char: "P"):
              *    S A M P L E          (logical index: 3, visual index: 3)
              *    ^ (visualLeftPart)
              *    ^ (visualRightSide)
              *    visualLeftLength == 3
              *    ^^^^^^ (subWidth)
              *    ^^^^^^^^ (aprocessor.GetWidth() -- with visualRightSide)
              *          ^^ (posResolve->visualWidth)
              *
              * RTL (current char: "M"):
              *    E L P M A S          (logical index: 2, visual index: 3)
              *        ^ (visualLeftPart)
              *          ^ (visualRightSide)
              *    visualLeftLength == 3
              *    ^^^^^^ (subWidth)
              *    ^^^^^^^^ (aprocessor.GetWidth() -- with visualRightSide)
              *          ^^ (posResolve->visualWidth)
              */
             nscoord subWidth;
             // The position in the text where this run's "left part" begins.
             const char16_t* visualLeftPart, *visualRightSide;
             if (level & 1) {
               // One day, son, this could all be replaced with mBidiEngine.GetVisualIndex ...
               posResolve->visualIndex = visualStart + (subRunLength - (posResolve->logicalIndex + 1 - start));
               // Skipping to the "left part".
               visualLeftPart = aText + posResolve->logicalIndex + 1;
               // Skipping to the right side of the current character
               visualRightSide = visualLeftPart - 1;
             }
             else {
               posResolve->visualIndex = visualStart + (posResolve->logicalIndex - start);
               // Skipping to the "left part".
               visualLeftPart = aText + start;
               // In LTR mode this is the same as visualLeftPart
               visualRightSide = visualLeftPart;
             }
             // The delta between the start of the run and the left part's end.
             int32_t visualLeftLength = posResolve->visualIndex - visualStart;
             aprocessor.SetText(visualLeftPart, visualLeftLength, nsBidiDirection(level & 1));
             subWidth = aprocessor.GetWidth();
             aprocessor.SetText(visualRightSide, visualLeftLength + 1, nsBidiDirection(level & 1));
             posResolve->visualLeftTwips = xOffset + subWidth;
             posResolve->visualWidth = aprocessor.GetWidth() - subWidth;
           }
         }
       }
       if (!(level & 1)) {
         xOffset += width;
       }
       --subRunCount;
       start = lineOffset;
       subRunLimit = typeLimit;
       subRunLength = typeLimit - lineOffset;
     } // while
     if (level & 1) {
       xOffset = xEndRun;
     }
     visualStart += length;
   } // for
   if (aWidth) {
     *aWidth = totalWidth;
   }
   return NS_OK;
 }
 class MOZ_STACK_CLASS nsIRenderingContextBidiProcessor : public nsBidiPresUtils::BidiProcessor {
 public:
   nsIRenderingContextBidiProcessor(nsRenderingContext* aCtx,
                                    nsRenderingContext* aTextRunConstructionContext,
                                    const nsPoint&       aPt)
     : mCtx(aCtx), mTextRunConstructionContext(aTextRunConstructionContext), mPt(aPt) { }
   ~nsIRenderingContextBidiProcessor()
   {
     mCtx->SetTextRunRTL(false);
   }
   virtual void SetText(const char16_t* aText,
                        int32_t          aLength,
                        nsBidiDirection  aDirection) MOZ_OVERRIDE
   {
     mTextRunConstructionContext->SetTextRunRTL(aDirection==NSBIDI_RTL);
     mText = aText;
     mLength = aLength;
   }
   virtual nscoord GetWidth() MOZ_OVERRIDE
   {
     return mTextRunConstructionContext->GetWidth(mText, mLength);
   }
   virtual void DrawText(nscoord aXOffset,
                         nscoord) MOZ_OVERRIDE
   {
     mCtx->FontMetrics()->DrawString(mText, mLength, mPt.x + aXOffset, mPt.y,
                                     mCtx, mTextRunConstructionContext);
   }
 private:
   nsRenderingContext* mCtx;
   nsRenderingContext* mTextRunConstructionContext;
   nsPoint mPt;
   const char16_t* mText;
   int32_t mLength;
 };
 nsresult nsBidiPresUtils::ProcessTextForRenderingContext(const char16_t*       aText,
                                                          int32_t                aLength,
                                                          nsBidiLevel            aBaseLevel,
                                                          nsPresContext*         aPresContext,
                                                          nsRenderingContext&   aRenderingContext,
                                                          nsRenderingContext&   aTextRunConstructionContext,
                                                          Mode                   aMode,
                                                          nscoord                aX,
                                                          nscoord                aY,
                                                          nsBidiPositionResolve* aPosResolve,
                                                          int32_t                aPosResolveCount,
                                                          nscoord*               aWidth)
 {
   nsIRenderingContextBidiProcessor processor(&aRenderingContext, &aTextRunConstructionContext, nsPoint(aX, aY));
   nsBidi bidiEngine;
   return ProcessText(aText, aLength, aBaseLevel, aPresContext, processor,
                      aMode, aPosResolve, aPosResolveCount, aWidth, &bidiEngine);
 }
 /* static */
 void nsBidiPresUtils::WriteReverse(const char16_t* aSrc,
                                    uint32_t aSrcLength,
                                    char16_t* aDest)
 {
   char16_t* dest = aDest + aSrcLength;
   mozilla::unicode::ClusterIterator iter(aSrc, aSrcLength);
   while (!iter.AtEnd()) {
     iter.Next();
     for (const char16_t *cp = iter; cp > aSrc; ) {
       // Here we rely on the fact that there are no non-BMP mirrored pairs
       // currently in Unicode, so we don't need to look for surrogates
       *--dest = mozilla::unicode::GetMirroredChar(*--cp);
     }
     aSrc = iter;
   }
   NS_ASSERTION(dest == aDest, "Whole string not copied");
 }
 /* static */
 bool nsBidiPresUtils::WriteLogicalToVisual(const char16_t* aSrc,
                                            uint32_t aSrcLength,
                                            char16_t* aDest,
                                            nsBidiLevel aBaseDirection,
                                            nsBidi* aBidiEngine)
 {
   const char16_t* src = aSrc;
   nsresult rv = aBidiEngine->SetPara(src, aSrcLength, aBaseDirection, nullptr);
   if (NS_FAILED(rv)) {
     return false;
   }
   nsBidiDirection dir;
   rv = aBidiEngine->GetDirection(&dir);
   // NSBIDI_LTR returned from GetDirection means the whole text is LTR
   if (NS_FAILED(rv) || dir == NSBIDI_LTR) {
     return false;
   }
   int32_t runCount;
   rv = aBidiEngine->CountRuns(&runCount);
   if (NS_FAILED(rv)) {
     return false;
   }
   int32_t runIndex, start, length;
   char16_t* dest = aDest;
   for (runIndex = 0; runIndex < runCount; ++runIndex) {
     rv = aBidiEngine->GetVisualRun(runIndex, &start, &length, &dir);
     if (NS_FAILED(rv)) {
       return false;
     }
     src = aSrc + start;
     if (dir == NSBIDI_RTL) {
       WriteReverse(src, length, dest);
       dest += length;
     } else {
       do {
         NS_ASSERTION(src >= aSrc && src < aSrc + aSrcLength,
                      "logical index out of range");
         NS_ASSERTION(dest < aDest + aSrcLength, "visual index out of range");
         *(dest++) = *(src++);
       } while (--length);
     }
   }
   NS_ASSERTION(static_cast<uint32_t>(dest - aDest) == aSrcLength,
                "whole string not copied");
   return true;
 }
 void nsBidiPresUtils::CopyLogicalToVisual(const nsAString& aSource,
                                           nsAString& aDest,
                                           nsBidiLevel aBaseDirection,
                                           bool aOverride)
 {
   aDest.SetLength(0);
   uint32_t srcLength = aSource.Length();
   if (srcLength == 0)
     return;
   if (!aDest.SetLength(srcLength, fallible_t())) {
     return;
   }
   nsAString::const_iterator fromBegin, fromEnd;
   nsAString::iterator toBegin;
   aSource.BeginReading(fromBegin);
   aSource.EndReading(fromEnd);
   aDest.BeginWriting(toBegin);
   if (aOverride) {
     if (aBaseDirection == NSBIDI_RTL) {
       // no need to use the converter -- just copy the string in reverse order
       WriteReverse(fromBegin.get(), srcLength, toBegin.get());
     } else {
       // if aOverride && aBaseDirection == NSBIDI_LTR, fall through to the
       // simple copy
       aDest.SetLength(0);
     }
   } else {
     nsBidi bidiEngine;
     if (!WriteLogicalToVisual(fromBegin.get(), srcLength, toBegin.get(),
                              aBaseDirection, &bidiEngine)) {
       aDest.SetLength(0);
     }
   }
   if (aDest.IsEmpty()) {
     // Either there was an error or the source is unidirectional
     //  left-to-right. In either case, just copy source to dest.
     CopyUnicodeTo(aSource.BeginReading(fromBegin), aSource.EndReading(fromEnd),
                   aDest);
   }
 }
 /* static */
 nsBidiLevel
 nsBidiPresUtils::BidiLevelFromStyle(nsStyleContext* aStyleContext)
 {
   if (aStyleContext->StyleTextReset()->mUnicodeBidi &
       NS_STYLE_UNICODE_BIDI_PLAINTEXT) {
     return NSBIDI_DEFAULT_LTR;
   }
   if (aStyleContext->StyleVisibility()->mDirection == NS_STYLE_DIRECTION_RTL) {
     return NSBIDI_RTL;
   }
   return NSBIDI_LTR;
 }

The Tor Browser / annotate

layout/base/nsBidiPresUtils.cpp@6474c204b198 (annotated)

layout/base/nsBidiPresUtils.cpp