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gecko-dev/layout/base/nsBidiPresUtils.cpp

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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 "mozilla/IntegerRange.h"
#include "mozilla/dom/Text.h"
#include "gfxContext.h"
#include "nsFontMetrics.h"
#include "nsGkAtoms.h"
#include "nsPresContext.h"
#include "nsBidiUtils.h"
#include "nsCSSFrameConstructor.h"
#include "nsContainerFrame.h"
#include "nsInlineFrame.h"
#include "nsPlaceholderFrame.h"
#include "nsPointerHashKeys.h"
#include "nsFirstLetterFrame.h"
#include "nsUnicodeProperties.h"
#include "nsTextFrame.h"
#include "nsBlockFrame.h"
#include "nsIFrameInlines.h"
#include "nsStyleStructInlines.h"
#include "RubyUtils.h"
#include "nsRubyFrame.h"
#include "nsRubyBaseFrame.h"
#include "nsRubyTextFrame.h"
#include "nsRubyBaseContainerFrame.h"
#include "nsRubyTextContainerFrame.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 kLRI = 0x2066;
static const char16_t kRLI = 0x2067;
static const char16_t kFSI = 0x2068;
static const char16_t kPDI = 0x2069;
// All characters with Bidi type Segment Separator or Block Separator
static const char16_t kSeparators[] = {
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)
static bool IsIsolateControl(char16_t aChar) {
return aChar == kLRI || aChar == kRLI || aChar == kFSI;
}
// Given a ComputedStyle, return any bidi control character necessary to
// implement style properties that override directionality (i.e. if it has
// unicode-bidi:bidi-override, or text-orientation:upright in vertical
// writing mode) when applying the bidi algorithm.
//
// Returns 0 if no override control character is implied by this style.
static char16_t GetBidiOverride(ComputedStyle* aComputedStyle) {
const nsStyleVisibility* vis = aComputedStyle->StyleVisibility();
if ((vis->mWritingMode == NS_STYLE_WRITING_MODE_VERTICAL_RL ||
vis->mWritingMode == NS_STYLE_WRITING_MODE_VERTICAL_LR) &&
vis->mTextOrientation == NS_STYLE_TEXT_ORIENTATION_UPRIGHT) {
return kLRO;
}
const nsStyleTextReset* text = aComputedStyle->StyleTextReset();
if (text->mUnicodeBidi & NS_STYLE_UNICODE_BIDI_BIDI_OVERRIDE) {
return NS_STYLE_DIRECTION_RTL == vis->mDirection ? kRLO : kLRO;
}
return 0;
}
// Given a ComputedStyle, return any bidi control character necessary to
// implement style properties that affect bidi resolution (i.e. if it
// has unicode-bidiembed, isolate, or plaintext) when applying the bidi
// algorithm.
//
// Returns 0 if no control character is implied by the style.
//
// Note that GetBidiOverride and GetBidiControl need to be separate
// because in the case of unicode-bidi:isolate-override we need both
// FSI and LRO/RLO.
static char16_t GetBidiControl(ComputedStyle* aComputedStyle) {
const nsStyleVisibility* vis = aComputedStyle->StyleVisibility();
const nsStyleTextReset* text = aComputedStyle->StyleTextReset();
if (text->mUnicodeBidi & NS_STYLE_UNICODE_BIDI_EMBED) {
return NS_STYLE_DIRECTION_RTL == vis->mDirection ? kRLE : kLRE;
}
if (text->mUnicodeBidi & NS_STYLE_UNICODE_BIDI_ISOLATE) {
if (text->mUnicodeBidi & NS_STYLE_UNICODE_BIDI_BIDI_OVERRIDE) {
// isolate-override
return kFSI;
}
// <bdi> element already has its directionality set from content so
// we never need to return kFSI.
return NS_STYLE_DIRECTION_RTL == vis->mDirection ? kRLI : kLRI;
}
if (text->mUnicodeBidi & NS_STYLE_UNICODE_BIDI_PLAINTEXT) {
return kFSI;
}
return 0;
}
struct MOZ_STACK_CLASS BidiParagraphData {
nsAutoString mBuffer;
AutoTArray<char16_t, 16> mEmbeddingStack;
AutoTArray<nsIFrame*, 16> mLogicalFrames;
AutoTArray<nsLineBox*, 16> mLinePerFrame;
nsDataHashtable<nsPtrHashKey<const nsIContent>, int32_t> mContentToFrameIndex;
// Cached presentation context for the frames we're processing.
nsPresContext* mPresContext;
bool mIsVisual;
bool mRequiresBidi;
nsBidiLevel mParaLevel;
nsIContent* mPrevContent;
nsIFrame* mPrevFrame;
// Cache the block frame which needs bidi resolution.
const nsIFrame* mBlock;
#ifdef DEBUG
// Only used for NOISY debug output.
nsBlockFrame* mCurrentBlock;
#endif
explicit BidiParagraphData(nsBlockFrame* aBlockFrame)
: mPresContext(aBlockFrame->PresContext()),
mIsVisual(mPresContext->IsVisualMode()),
mRequiresBidi(false),
mParaLevel(nsBidiPresUtils::BidiLevelFromStyle(aBlockFrame->Style())),
mPrevContent(nullptr),
mPrevFrame(nullptr),
mBlock(aBlockFrame)
#ifdef DEBUG
,
mCurrentBlock(aBlockFrame)
#endif
{
MOZ_ASSERT(mBlock->FirstContinuation() == mBlock,
"mBlock must be the first continuation!");
if (mParaLevel > 0) {
mRequiresBidi = true;
}
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->IsXULElement()) {
mIsVisual = false;
break;
}
}
}
}
nsresult SetPara() {
return mPresContext->GetBidiEngine().SetPara(mBuffer.get(), BufferLength(),
mParaLevel);
}
/**
* 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 (paraLevel == NSBIDI_DEFAULT_LTR || paraLevel == NSBIDI_DEFAULT_RTL) {
paraLevel = mPresContext->GetBidiEngine().GetParaLevel();
}
return paraLevel;
}
nsBidiDirection GetDirection() {
return mPresContext->GetBidiEngine().GetDirection();
}
nsresult CountRuns(int32_t* runCount) {
return mPresContext->GetBidiEngine().CountRuns(runCount);
}
void GetLogicalRun(int32_t aLogicalStart, int32_t* aLogicalLimit,
nsBidiLevel* aLevel) {
mPresContext->GetBidiEngine().GetLogicalRun(aLogicalStart, aLogicalLimit,
aLevel);
if (mIsVisual) {
*aLevel = GetParaLevel();
}
}
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 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 AppendPopChar(char16_t aCh) {
AppendControlChar(IsIsolateControl(aCh) ? kPDI : kPDF);
}
void PopBidiControl(char16_t aCh) {
MOZ_ASSERT(mEmbeddingStack.Length(), "embedding/override underflow");
MOZ_ASSERT(aCh == mEmbeddingStack.LastElement());
AppendPopChar(aCh);
mEmbeddingStack.TruncateLength(mEmbeddingStack.Length() - 1);
}
void ClearBidiControls() {
for (char16_t c : Reversed(mEmbeddingStack)) {
AppendPopChar(c);
}
}
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 && !parent->IsBlockFrameOrSubclass()) {
child = parent;
parent = nsLayoutUtils::GetParentOrPlaceholderFor(child);
}
NS_ASSERTION(parent, "aFrame is not a descendent of a block frame");
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 MOZ_STACK_CLASS BidiLineData {
AutoTArray<nsIFrame*, 16> mLogicalFrames;
AutoTArray<nsIFrame*, 16> mVisualFrames;
AutoTArray<int32_t, 16> mIndexMap;
AutoTArray<uint8_t, 16> 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
*/
bool isReordered = false;
bool hasRTLFrames = false;
bool hasVirtualControls = false;
auto appendFrame = [&](nsIFrame* frame, nsBidiLevel level) {
mLogicalFrames.AppendElement(frame);
mLevels.AppendElement(level);
mIndexMap.AppendElement(0);
if (IS_LEVEL_RTL(level)) {
hasRTLFrames = true;
}
};
bool firstFrame = true;
for (nsIFrame* frame = aFirstFrameOnLine; frame && aNumFramesOnLine--;
frame = frame->GetNextSibling()) {
FrameBidiData bidiData = nsBidiPresUtils::GetFrameBidiData(frame);
// Ignore virtual control before the first frame. Doing so should
// not affect the visual result, but could avoid running into the
// stripping code below for many cases.
if (!firstFrame && bidiData.precedingControl != kBidiLevelNone) {
appendFrame(NS_BIDI_CONTROL_FRAME, bidiData.precedingControl);
hasVirtualControls = true;
}
appendFrame(frame, bidiData.embeddingLevel);
firstFrame = false;
}
// Reorder the line
nsBidi::ReorderVisual(mLevels.Elements(), FrameCount(),
mIndexMap.Elements());
// Strip virtual frames
if (hasVirtualControls) {
auto originalCount = mLogicalFrames.Length();
AutoTArray<int32_t, 16> realFrameMap;
realFrameMap.SetCapacity(originalCount);
size_t count = 0;
for (auto i : IntegerRange(originalCount)) {
if (mLogicalFrames[i] == NS_BIDI_CONTROL_FRAME) {
realFrameMap.AppendElement(-1);
} else {
mLogicalFrames[count] = mLogicalFrames[i];
mLevels[count] = mLevels[i];
realFrameMap.AppendElement(count);
count++;
}
}
// Only keep index map for real frames.
for (size_t i = 0, j = 0; i < originalCount; ++i) {
auto newIndex = realFrameMap[mIndexMap[i]];
if (newIndex != -1) {
mIndexMap[j] = newIndex;
j++;
}
}
mLogicalFrames.TruncateLength(count);
mLevels.TruncateLength(count);
mIndexMap.TruncateLength(count);
}
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;
}
int32_t FrameCount() const { return mLogicalFrames.Length(); }
nsIFrame* LogicalFrameAt(int32_t aIndex) const {
return mLogicalFrames[aIndex];
}
nsIFrame* VisualFrameAt(int32_t aIndex) const {
return mVisualFrames[aIndex];
}
};
#ifdef DEBUG
extern "C" {
void MOZ_EXPORT DumpFrameArray(const nsTArray<nsIFrame*>& aFrames) {
for (nsIFrame* frame : aFrames) {
if (frame == NS_BIDI_CONTROL_FRAME) {
fprintf_stderr(stderr, "(Bidi control frame)\n");
} else {
frame->List();
}
}
}
void MOZ_EXPORT DumpBidiLine(BidiLineData* aData, bool aVisualOrder) {
DumpFrameArray(aVisualOrder ? aData->mVisualFrames : aData->mLogicalFrames);
}
}
#endif
/* 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.
LayoutFrameType frameType = aFrame->Type();
return (aFrame->IsFrameOfType(nsIFrame::eBidiInlineContainer) &&
frameType != LayoutFrameType::Line) ||
frameType == LayoutFrameType::Text;
}
// Should this frame be treated as a leaf (e.g. when building mLogicalFrames)?
static bool IsBidiLeaf(nsIFrame* aFrame) {
nsIFrame* kid = aFrame->PrincipalChildList().FirstChild();
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(nsContainerFrame* aParent,
nsIFrame* aFrame) {
nsPresContext* presContext = aParent->PresContext();
nsIPresShell* presShell = presContext->PresShell();
nsIFrame* frame = aFrame;
nsContainerFrame* parent = aParent;
nsContainerFrame* newParent;
while (IsBidiSplittable(parent)) {
nsContainerFrame* 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 = static_cast<nsContainerFrame*>(
presShell->FrameConstructor()->CreateContinuingFrame(
presContext, parent, grandparent, false));
nsFrameList tail = parent->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.
newParent->InsertFrames(nsIFrame::kNoReflowPrincipalList, nullptr, tail);
// The list name kNoReflowPrincipalList would indicate we don't want
// reflow
nsFrameList temp(newParent, newParent);
grandparent->InsertFrames(nsIFrame::kNoReflowPrincipalList, parent, temp);
}
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) {
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) {
MOZ_ASSERT(aNewFrame, "null OUT ptr");
MOZ_ASSERT(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");
nsContainerFrame* 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->IsLetterFrame() && 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);
parent->InsertFrames(nsIFrame::kNoReflowPrincipalList, aFrame, temp);
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 isolates, embeddings, and overrides set by CSS, <bdi>, 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(aBlockFrame);
// Handle bidi-override being set on the block itself before calling
// TraverseFrames.
// No need to call GetBidiControl as well, because isolate and embed
// values of unicode-bidi property are redundant on block elements.
// unicode-bidi:plaintext on a block element is handled by block frame
// via using nsIFrame::GetWritingMode(nsIFrame*).
char16_t ch = GetBidiOverride(aBlockFrame->Style());
if (ch != 0) {
bpd.PushBidiControl(ch);
bpd.mRequiresBidi = true;
} else {
// If there are no unicode-bidi properties and no RTL characters in the
// block's content, then it is pure LTR and we can skip the rest of bidi
// resolution.
nsIContent* currContent = nullptr;
for (nsBlockFrame* block = aBlockFrame; block;
block = static_cast<nsBlockFrame*>(block->GetNextContinuation())) {
block->RemoveStateBits(NS_BLOCK_NEEDS_BIDI_RESOLUTION);
if (!bpd.mRequiresBidi &&
ChildListMayRequireBidi(block->PrincipalChildList().FirstChild(),
&currContent)) {
bpd.mRequiresBidi = true;
}
if (!bpd.mRequiresBidi) {
nsBlockFrame::FrameLines* overflowLines = block->GetOverflowLines();
if (overflowLines) {
if (ChildListMayRequireBidi(overflowLines->mFrames.FirstChild(),
&currContent)) {
bpd.mRequiresBidi = true;
}
}
}
}
if (!bpd.mRequiresBidi) {
return NS_OK;
}
}
for (nsBlockFrame* block = aBlockFrame; block;
block = static_cast<nsBlockFrame*>(block->GetNextContinuation())) {
#ifdef DEBUG
bpd.mCurrentBlock = block;
#endif
block->RemoveStateBits(NS_BLOCK_NEEDS_BIDI_RESOLUTION);
nsBlockInFlowLineIterator it(block, block->LinesBegin());
bpd.mPrevFrame = nullptr;
TraverseFrames(&it, block->PrincipalChildList().FirstChild(), &bpd);
nsBlockFrame::FrameLines* overflowLines = block->GetOverflowLines();
if (overflowLines) {
nsBlockInFlowLineIterator it(block, overflowLines->mLines.begin(), true);
bpd.mPrevFrame = nullptr;
TraverseFrames(&it, overflowLines->mFrames.FirstChild(), &bpd);
}
}
if (ch != 0) {
bpd.PopBidiControl(ch);
}
return ResolveParagraph(&bpd);
}
nsresult nsBidiPresUtils::ResolveParagraph(BidiParagraphData* aBpd) {
if (aBpd->BufferLength() < 1) {
return NS_OK;
}
aBpd->mBuffer.ReplaceChar(kSeparators, kSpace);
int32_t runCount;
nsresult rv = aBpd->SetPara();
NS_ENSURE_SUCCESS(rv, rv);
nsBidiLevel 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 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;
nsLineBox* currentLine = nullptr;
#ifdef DEBUG
# ifdef NOISY_BIDI
printf(
"Before Resolve(), mCurrentBlock=%p, mBuffer='%s', frameCount=%d, "
"runCount=%d\n",
(void*)aBpd->mCurrentBlock, NS_ConvertUTF16toUTF8(aBpd->mBuffer).get(),
frameCount, runCount);
# ifdef REALLY_NOISY_BIDI
printf(" block frame tree=:\n");
aBpd->mCurrentBlock->List(stdout);
# endif
# endif
#endif
if (runCount == 1 && frameCount == 1 && 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) {
FrameBidiData bidiData = frame->GetBidiData();
if (!bidiData.embeddingLevel && !bidiData.baseLevel) {
#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* lastRealFrame = nullptr;
nsBidiLevel lastEmbeddingLevel = kBidiLevelNone;
nsBidiLevel precedingControl = kBidiLevelNone;
auto storeBidiDataToFrame = [&]() {
FrameBidiData bidiData;
bidiData.embeddingLevel = embeddingLevel;
bidiData.baseLevel = aBpd->GetParaLevel();
// If a control character doesn't have a lower embedding level than
// both the preceding and the following frame, it isn't something
// needed for getting the correct result. This optimization should
// remove almost all of embeds and overrides, and some of isolates.
if (precedingControl >= embeddingLevel ||
precedingControl >= lastEmbeddingLevel) {
bidiData.precedingControl = kBidiLevelNone;
} else {
bidiData.precedingControl = precedingControl;
}
precedingControl = kBidiLevelNone;
lastEmbeddingLevel = embeddingLevel;
frame->SetProperty(nsIFrame::BidiDataProperty(), bidiData);
};
for (;;) {
if (fragmentLength <= 0) {
// Get the next frame from mLogicalFrames
if (++frameIndex >= frameCount) {
break;
}
frame = aBpd->FrameAt(frameIndex);
if (frame == NS_BIDI_CONTROL_FRAME || !frame->IsTextFrame()) {
/*
* 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 {
currentLine = aBpd->GetLineForFrameAt(frameIndex);
content = frame->GetContent();
if (!content) {
rv = NS_OK;
break;
}
contentTextLength = content->TextLength();
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) {
// We've run out of runs of text; but don't forget to store bidi data
// to the frame before breaking out of the loop (bug 1426042).
storeBidiDataToFrame();
if (isTextFrame) {
frame->AdjustOffsetsForBidi(contentOffset,
contentOffset + fragmentLength);
}
break;
}
int32_t lineOffset = logicalLimit;
aBpd->GetLogicalRun(lineOffset, &logicalLimit, &embeddingLevel);
runLength = logicalLimit - lineOffset;
} // if (runLength <= 0)
if (frame == NS_BIDI_CONTROL_FRAME) {
// In theory, we only need to do this for isolates. However, it is
// easier to do this for all here because we do not maintain the
// index to get corresponding character from buffer. Since we do
// have proper embedding level for all those characters, including
// them wouldn't affect the final result.
precedingControl = std::min(precedingControl, embeddingLevel);
} else {
storeBidiDataToFrame();
if (isTextFrame) {
if (contentTextLength == 0) {
// Set the base level and embedding level of the current run even
// on an empty frame. Otherwise frame reordering will not be correct.
frame->AdjustOffsetsForBidi(0, 0);
// Nothing more to do for an empty frame.
continue;
}
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, contentOffset, runEnd);
if (NS_FAILED(rv)) {
break;
}
nextBidi->AdjustOffsetsForBidi(runEnd,
contentOffset + fragmentLength);
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);
frameIndex = newIndex;
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);
}
} 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);
}
} // isTextFrame
} // not bidi control frame
int32_t temp = runLength;
runLength -= fragmentLength;
fragmentLength -= temp;
// Record last real frame so that we can do splitting properly even
// if a run ends after a virtual bidi control frame.
if (frame != NS_BIDI_CONTROL_FRAME) {
lastRealFrame = frame;
}
if (lastRealFrame && fragmentLength <= 0) {
// If the frame is at the end of a run, and this is not the end of our
// paragraph, 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 && !lastRealFrame->GetNextInFlow()) {
if (numRun + 1 < runCount) {
nsIFrame* child = lastRealFrame;
nsContainerFrame* parent = child->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 if (frame != NS_BIDI_CONTROL_FRAME) {
// 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
#ifdef DEBUG
# ifdef REALLY_NOISY_BIDI
printf("---\nAfter Resolve(), frameTree =:\n");
aBpd->mCurrentBlock->List(stdout);
printf("===\n");
# endif
#endif
return rv;
}
void nsBidiPresUtils::TraverseFrames(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();
// 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 (childFrame->IsPlaceholderFrame()) {
nsIFrame* realFrame =
nsPlaceholderFrame::GetRealFrameForPlaceholder(childFrame);
if (realFrame->IsLetterFrame()) {
frame = realFrame;
}
}
auto DifferentBidiValues = [](ComputedStyle* aSC1, nsIFrame* aFrame2) {
ComputedStyle* sc2 = aFrame2->Style();
return GetBidiControl(aSC1) != GetBidiControl(sc2) ||
GetBidiOverride(aSC1) != GetBidiOverride(sc2);
};
ComputedStyle* sc = frame->Style();
nsIFrame* nextContinuation = frame->GetNextContinuation();
nsIFrame* prevContinuation = frame->GetPrevContinuation();
bool isLastFrame =
!nextContinuation || DifferentBidiValues(sc, nextContinuation);
bool isFirstFrame =
!prevContinuation || DifferentBidiValues(sc, prevContinuation);
char16_t controlChar = 0;
char16_t overrideChar = 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();
}
controlChar = GetBidiControl(sc);
overrideChar = GetBidiOverride(sc);
// Add dummy frame pointers representing bidi control codes before
// the first frames of elements specifying override, isolation, or
// plaintext.
if (isFirstFrame) {
if (controlChar != 0) {
aBpd->PushBidiControl(controlChar);
}
if (overrideChar != 0) {
aBpd->PushBidiControl(overrideChar);
}
}
}
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
LayoutFrameType frameType = frame->Type();
if (LayoutFrameType::Text == frameType) {
if (content != aBpd->mPrevContent) {
aBpd->mPrevContent = content;
if (!frame->StyleText()->NewlineIsSignificant(
static_cast<nsTextFrame*>(frame))) {
content->GetAsText()->AppendTextTo(aBpd->mBuffer);
} else {
/*
* For preformatted text we have to do bidi resolution on each line
* separately.
*/
nsAutoString text;
content->GetAsText()->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;
}
// Mark the line before the newline as dirty.
aBpd->GetLineForFrameAt(aBpd->FrameCount() - 1)->MarkDirty();
}
ResolveParagraphWithinBlock(aBpd);
if (!nextSibling && !createdContinuation) {
break;
} else if (next) {
frame = next;
aBpd->AppendFrame(frame, aLineIter);
// Mark the line after the newline as dirty.
aBpd->GetLineForFrameAt(aBpd->FrameCount() - 1)->MarkDirty();
}
/*
* 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 (LayoutFrameType::Br == frameType) {
// break frame -- append line separator
aBpd->AppendUnichar(kLineSeparator);
ResolveParagraphWithinBlock(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->IsHTMLElement(nsGkAtoms::wbr) ? kZWSP : kObjectSubstitute);
if (!frame->IsInlineOutside()) {
// if it is not inline, end the paragraph
ResolveParagraphWithinBlock(aBpd);
}
}
} else {
// For a non-leaf frame, recurse into TraverseFrames
nsIFrame* kid = frame->PrincipalChildList().FirstChild();
MOZ_ASSERT(!frame->GetChildList(nsIFrame::kOverflowList).FirstChild(),
"should have drained the overflow list above");
if (kid) {
TraverseFrames(aLineIter, kid, aBpd);
}
}
// If the element is attributed by dir, indicate direction pop (add PDF
// frame)
if (isLastFrame) {
// Add a dummy frame pointer representing a bidi control code after the
// last frame of an element specifying embedding or override
if (overrideChar != 0) {
aBpd->PopBidiControl(overrideChar);
}
if (controlChar != 0) {
aBpd->PopBidiControl(controlChar);
}
}
childFrame = nextSibling;
} while (childFrame);
MOZ_ASSERT(initialLineContainer == aLineIter->GetContainer());
}
bool nsBidiPresUtils::ChildListMayRequireBidi(nsIFrame* aFirstChild,
nsIContent** aCurrContent) {
MOZ_ASSERT(!aFirstChild || !aFirstChild->GetPrevSibling(),
"Expecting to traverse from the start of a child list");
for (nsIFrame* childFrame = aFirstChild; childFrame;
childFrame = childFrame->GetNextSibling()) {
nsIFrame* frame = childFrame;
// If the real frame for a placeholder is a first-letter frame, we need to
// consider its contents for potential Bidi resolution.
if (childFrame->IsPlaceholderFrame()) {
nsIFrame* realFrame =
nsPlaceholderFrame::GetRealFrameForPlaceholder(childFrame);
if (realFrame->IsLetterFrame()) {
frame = realFrame;
}
}
// If unicode-bidi properties are present, we should do bidi resolution.
ComputedStyle* sc = frame->Style();
if (GetBidiControl(sc) || GetBidiOverride(sc)) {
return true;
}
if (IsBidiLeaf(frame)) {
if (frame->IsTextFrame()) {
// If the frame already has a BidiDataProperty, we know we need to
// perform bidi resolution (even if no bidi content is NOW present --
// we might need to remove the property set by a previous reflow, if
// content has changed; see bug 1366623).
if (frame->HasProperty(nsIFrame::BidiDataProperty())) {
return true;
}
// Check whether the text frame has any RTL characters; if so, bidi
// resolution will be needed.
nsIContent* content = frame->GetContent();
if (content != *aCurrContent) {
*aCurrContent = content;
const nsTextFragment* txt = content->GetText();
if (txt->Is2b() &&
HasRTLChars(MakeSpan(txt->Get2b(), txt->GetLength()))) {
return true;
}
}
}
} else if (ChildListMayRequireBidi(frame->PrincipalChildList().FirstChild(),
aCurrContent)) {
return true;
}
}
return false;
}
void nsBidiPresUtils::ResolveParagraphWithinBlock(BidiParagraphData* aBpd) {
aBpd->ClearBidiControls();
ResolveParagraph(aBpd);
aBpd->ResetData();
}
/* static */
nscoord nsBidiPresUtils::ReorderFrames(nsIFrame* aFirstFrameOnLine,
int32_t aNumFramesOnLine,
WritingMode aLineWM,
const nsSize& aContainerSize,
nscoord aStart) {
nsSize containerSize(aContainerSize);
// If this line consists of a line frame, reorder the line frame's children.
if (aFirstFrameOnLine->IsLineFrame()) {
// The line frame is positioned at the start-edge, so use its size
// as the container size.
containerSize = aFirstFrameOnLine->GetSize();
aFirstFrameOnLine = aFirstFrameOnLine->PrincipalChildList().FirstChild();
if (!aFirstFrameOnLine) {
return 0;
}
// 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);
return RepositionInlineFrames(&bld, aLineWM, containerSize, aStart);
}
nsIFrame* nsBidiPresUtils::GetFirstLeaf(nsIFrame* aFrame) {
nsIFrame* firstLeaf = aFrame;
while (!IsBidiLeaf(firstLeaf)) {
nsIFrame* firstChild = firstLeaf->PrincipalChildList().FirstChild();
nsIFrame* realFrame = nsPlaceholderFrame::GetRealFrameFor(firstChild);
firstLeaf = (realFrame->IsLetterFrame()) ? realFrame : firstChild;
}
return firstLeaf;
}
FrameBidiData nsBidiPresUtils::GetFrameBidiData(nsIFrame* aFrame) {
return GetFirstLeaf(aFrame)->GetBidiData();
}
nsBidiLevel nsBidiPresUtils::GetFrameEmbeddingLevel(nsIFrame* aFrame) {
return GetFirstLeaf(aFrame)->GetEmbeddingLevel();
}
nsBidiLevel nsBidiPresUtils::GetFrameBaseLevel(nsIFrame* aFrame) {
nsIFrame* firstLeaf = aFrame;
while (!IsBidiLeaf(firstLeaf)) {
firstLeaf = firstLeaf->PrincipalChildList().FirstChild();
}
return firstLeaf->GetBaseLevel();
}
void nsBidiPresUtils::IsFirstOrLast(
nsIFrame* aFrame, const nsContinuationStates* aContinuationStates,
bool aSpanDirMatchesLineDir, 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.
*/
bool firstInLineOrder, lastInLineOrder;
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);
firstInLineOrder = true;
firstFrameState = frameState;
} else {
// aFrame is not the first visual frame of its continuation chain
firstInLineOrder = false;
firstFrameState =
aContinuationStates->GetEntry(frameState->mFirstVisualFrame);
}
lastInLineOrder = (firstFrameState->mFrameCount == 1);
if (aSpanDirMatchesLineDir) {
aIsFirst = firstInLineOrder;
aIsLast = lastInLineOrder;
} else {
aIsFirst = lastInLineOrder;
aIsLast = firstInLineOrder;
}
if (frameState->mHasContOnPrevLines) {
aIsFirst = false;
}
if (firstFrameState->mHasContOnNextLines) {
aIsLast = false;
}
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--;
nsInlineFrame* testFrame = do_QueryFrame(aFrame);
if (testFrame) {
aFrame->AddStateBits(NS_INLINE_FRAME_BIDI_VISUAL_STATE_IS_SET);
if (aIsFirst) {
aFrame->AddStateBits(NS_INLINE_FRAME_BIDI_VISUAL_IS_FIRST);
} else {
aFrame->RemoveStateBits(NS_INLINE_FRAME_BIDI_VISUAL_IS_FIRST);
}
if (aIsLast) {
aFrame->AddStateBits(NS_INLINE_FRAME_BIDI_VISUAL_IS_LAST);
} else {
aFrame->RemoveStateBits(NS_INLINE_FRAME_BIDI_VISUAL_IS_LAST);
}
}
}
/* static */
void nsBidiPresUtils::RepositionRubyContentFrame(
nsIFrame* aFrame, WritingMode aFrameWM,
const LogicalMargin& aBorderPadding) {
const nsFrameList& childList = aFrame->PrincipalChildList();
if (childList.IsEmpty()) {
return;
}
// Reorder the children.
// XXX It currently doesn't work properly because we do not
// resolve frames inside ruby content frames.
nscoord isize =
ReorderFrames(childList.FirstChild(), childList.GetLength(), aFrameWM,
aFrame->GetSize(), aBorderPadding.IStart(aFrameWM));
isize += aBorderPadding.IEnd(aFrameWM);
if (aFrame->StyleText()->mRubyAlign == NS_STYLE_RUBY_ALIGN_START) {
return;
}
nscoord residualISize = aFrame->ISize(aFrameWM) - isize;
if (residualISize <= 0) {
return;
}
// When ruby-align is not "start", if the content does not fill this
// frame, we need to center the children.
const nsSize dummyContainerSize;
for (nsIFrame* child : childList) {
LogicalRect rect = child->GetLogicalRect(aFrameWM, dummyContainerSize);
rect.IStart(aFrameWM) += residualISize / 2;
child->SetRect(aFrameWM, rect, dummyContainerSize);
}
}
/* static */
nscoord nsBidiPresUtils::RepositionRubyFrame(
nsIFrame* aFrame, const nsContinuationStates* aContinuationStates,
const WritingMode aContainerWM, const LogicalMargin& aBorderPadding) {
LayoutFrameType frameType = aFrame->Type();
MOZ_ASSERT(RubyUtils::IsRubyBox(frameType));
nscoord icoord = 0;
WritingMode frameWM = aFrame->GetWritingMode();
bool isLTR = frameWM.IsBidiLTR();
nsSize frameSize = aFrame->GetSize();
if (frameType == LayoutFrameType::Ruby) {
icoord += aBorderPadding.IStart(frameWM);
// Reposition ruby segments in a ruby container
for (RubySegmentEnumerator e(static_cast<nsRubyFrame*>(aFrame)); !e.AtEnd();
e.Next()) {
nsRubyBaseContainerFrame* rbc = e.GetBaseContainer();
AutoRubyTextContainerArray textContainers(rbc);
nscoord segmentISize = RepositionFrame(
rbc, isLTR, icoord, aContinuationStates, frameWM, false, frameSize);
for (nsRubyTextContainerFrame* rtc : textContainers) {
nscoord isize = RepositionFrame(rtc, isLTR, icoord, aContinuationStates,
frameWM, false, frameSize);
segmentISize = std::max(segmentISize, isize);
}
icoord += segmentISize;
}
icoord += aBorderPadding.IEnd(frameWM);
} else if (frameType == LayoutFrameType::RubyBaseContainer) {
// Reposition ruby columns in a ruby segment
auto rbc = static_cast<nsRubyBaseContainerFrame*>(aFrame);
AutoRubyTextContainerArray textContainers(rbc);
for (RubyColumnEnumerator e(rbc, textContainers); !e.AtEnd(); e.Next()) {
RubyColumn column;
e.GetColumn(column);
nscoord columnISize =
RepositionFrame(column.mBaseFrame, isLTR, icoord, aContinuationStates,
frameWM, false, frameSize);
for (nsRubyTextFrame* rt : column.mTextFrames) {
nscoord isize = RepositionFrame(rt, isLTR, icoord, aContinuationStates,
frameWM, false, frameSize);
columnISize = std::max(columnISize, isize);
}
icoord += columnISize;
}
} else {
if (frameType == LayoutFrameType::RubyBase ||
frameType == LayoutFrameType::RubyText) {
RepositionRubyContentFrame(aFrame, frameWM, aBorderPadding);
}
// Note that, ruby text container is not present in all conditions
// above. It is intended, because the children of rtc are reordered
// with the children of ruby base container simultaneously. We only
// need to return its isize here, as it should not be changed.
icoord += aFrame->ISize(aContainerWM);
}
return icoord;
}
/* static */
nscoord nsBidiPresUtils::RepositionFrame(
nsIFrame* aFrame, bool aIsEvenLevel, nscoord aStartOrEnd,
const nsContinuationStates* aContinuationStates, WritingMode aContainerWM,
bool aContainerReverseDir, const nsSize& aContainerSize) {
nscoord lineSize =
aContainerWM.IsVertical() ? aContainerSize.height : aContainerSize.width;
NS_ASSERTION(lineSize != NS_UNCONSTRAINEDSIZE,
"Unconstrained inline line size in bidi frame reordering");
if (!aFrame) return 0;
bool isFirst, isLast;
WritingMode frameWM = aFrame->GetWritingMode();
IsFirstOrLast(aFrame, aContinuationStates,
aContainerWM.IsBidiLTR() == frameWM.IsBidiLTR(),
isFirst /* out */, isLast /* out */);
// We only need the margin if the frame is first or last in its own
// writing mode, but we're traversing the frames in the order of the
// container's writing mode. To get the right values, we set start and
// end margins on a logical margin in the frame's writing mode, and
// then convert the margin to the container's writing mode to set the
// coordinates.
// 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
nscoord frameISize = aFrame->ISize();
LogicalMargin frameMargin = aFrame->GetLogicalUsedMargin(frameWM);
LogicalMargin borderPadding = aFrame->GetLogicalUsedBorderAndPadding(frameWM);
// Since the visual order of frame could be different from the continuation
// order, we need to remove any inline border/padding [that is already applied
// based on continuation order] and then add it back based on the visual order
// (i.e. isFirst/isLast) to get the correct isize for the current frame.
// We don't need to do that for 'box-decoration-break:clone' because then all
// continuations have border/padding/margin applied.
if (aFrame->StyleBorder()->mBoxDecorationBreak ==
StyleBoxDecorationBreak::Slice) {
// First remove the border/padding that was applied based on logical order.
if (!aFrame->GetPrevContinuation()) {
frameISize -= borderPadding.IStart(frameWM);
}
if (!aFrame->GetNextContinuation()) {
frameISize -= borderPadding.IEnd(frameWM);
}
// Set margin/border/padding based on visual order.
if (!isFirst) {
frameMargin.IStart(frameWM) = 0;
borderPadding.IStart(frameWM) = 0;
}
if (!isLast) {
frameMargin.IEnd(frameWM) = 0;
borderPadding.IEnd(frameWM) = 0;
}
// Add the border/padding which is now based on visual order.
frameISize += borderPadding.IStartEnd(frameWM);
}
nscoord icoord = 0;
if (!IsBidiLeaf(aFrame)) {
bool reverseDir = aIsEvenLevel != frameWM.IsBidiLTR();
icoord += reverseDir ? borderPadding.IEnd(frameWM)
: borderPadding.IStart(frameWM);
LogicalSize logicalSize(frameWM, frameISize, aFrame->BSize());
nsSize frameSize = logicalSize.GetPhysicalSize(frameWM);
// Reposition the child frames
for (nsFrameList::Enumerator e(aFrame->PrincipalChildList()); !e.AtEnd();
e.Next()) {
icoord +=
RepositionFrame(e.get(), aIsEvenLevel, icoord, aContinuationStates,
frameWM, reverseDir, frameSize);
}
icoord += reverseDir ? borderPadding.IStart(frameWM)
: borderPadding.IEnd(frameWM);
} else if (RubyUtils::IsRubyBox(aFrame->Type())) {
icoord += RepositionRubyFrame(aFrame, aContinuationStates, aContainerWM,
borderPadding);
} else {
icoord +=
frameWM.IsOrthogonalTo(aContainerWM) ? aFrame->BSize() : frameISize;
}
// In the following variables, if aContainerReverseDir is true, i.e.
// the container is positioning its children in reverse of its logical
// direction, the "StartOrEnd" refers to the distance from the frame
// to the inline end edge of the container, elsewise, it refers to the
// distance to the inline start edge.
const LogicalMargin margin = frameMargin.ConvertTo(aContainerWM, frameWM);
nscoord marginStartOrEnd = aContainerReverseDir ? margin.IEnd(aContainerWM)
: margin.IStart(aContainerWM);
nscoord frameStartOrEnd = aStartOrEnd + marginStartOrEnd;
LogicalRect rect = aFrame->GetLogicalRect(aContainerWM, aContainerSize);
rect.ISize(aContainerWM) = icoord;
rect.IStart(aContainerWM) = aContainerReverseDir
? lineSize - frameStartOrEnd - icoord
: frameStartOrEnd;
aFrame->SetRect(aContainerWM, rect, aContainerSize);
return icoord + margin.IStartEnd(aContainerWM);
}
void nsBidiPresUtils::InitContinuationStates(
nsIFrame* aFrame, nsContinuationStates* aContinuationStates) {
aContinuationStates->PutEntry(aFrame);
if (!IsBidiLeaf(aFrame) || RubyUtils::IsRubyBox(aFrame->Type())) {
// Continue for child frames
for (nsIFrame* frame : aFrame->PrincipalChildList()) {
InitContinuationStates(frame, aContinuationStates);
}
}
}
/* static */
nscoord nsBidiPresUtils::RepositionInlineFrames(BidiLineData* aBld,
WritingMode aLineWM,
const nsSize& aContainerSize,
nscoord aStart) {
nscoord start = aStart;
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);
start += RepositionFrame(
frame, !(IS_LEVEL_RTL(aBld->mLevels[aBld->mIndexMap[index]])), start,
&continuationStates, aLineWM, false, aContainerSize);
}
return start;
}
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 aStart,
int32_t aEnd) {
MOZ_ASSERT(aNewFrame, "null OUT ptr");
MOZ_ASSERT(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) {
FrameBidiData bidiData = aFrame->GetBidiData();
bidiData.precedingControl = kBidiLevelNone;
for (int32_t index = aFirstIndex + 1; index <= aLastIndex; index++) {
nsIFrame* frame = aBpd->FrameAt(index);
if (frame != NS_BIDI_CONTROL_FRAME) {
// Make the frame and its continuation ancestors fluid,
// so they can be reused or deleted by normal reflow code
frame->SetProperty(nsIFrame::BidiDataProperty(), bidiData);
frame->AddStateBits(NS_FRAME_IS_BIDI);
// Go no further than the block which needs resolution.
while (frame && aBpd->mBlock != frame->FirstContinuation()) {
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) {
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;
int32_t charLen;
for (offset = aOffset; offset < aCharTypeLimit; offset += charLen) {
// 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.)
charLen = 1;
uint32_t ch = aText[offset];
if (IS_HEBREW_CHAR(ch)) {
charType = eCharType_RightToLeft;
} else if (IS_ARABIC_ALPHABETIC(ch)) {
charType = eCharType_RightToLeftArabic;
} else {
if (NS_IS_HIGH_SURROGATE(ch) && offset + 1 < aCharTypeLimit &&
NS_IS_LOW_SURROGATE(aText[offset + 1])) {
ch = SURROGATE_TO_UCS4(ch, aText[offset + 1]);
charLen = 2;
}
charType = unicode::GetBidiCat(ch);
}
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);
textBuffer.ReplaceChar(kSeparators, kSpace);
const char16_t* text = textBuffer.get();
nsresult rv = aBidiEngine->SetPara(text, aLength, aBaseLevel);
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;
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 = aBidiEngine->GetVisualRun(i, &start, &length);
nsBidiLevel level;
aBidiEngine->GetLogicalRun(start, &limit, &level);
dir = DIRECTION_FROM_LEVEL(level);
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 (dir == NSBIDI_RTL) {
aprocessor.SetText(text + start, subRunLength, dir);
width = aprocessor.GetWidth();
xOffset += width;
xEndRun = xOffset;
}
while (subRunCount > 0) {
// CalculateCharType can increment subRunCount if the run
// contains mixed character types
CalculateCharType(aBidiEngine, text, lineOffset, typeLimit, subRunLimit,
subRunLength, subRunCount, charType, prevType);
nsAutoString runVisualText;
runVisualText.Assign(text + start, subRunLength);
if (int32_t(runVisualText.Length()) < subRunLength)
return NS_ERROR_OUT_OF_MEMORY;
FormatUnicodeText(aPresContext, runVisualText.BeginWriting(),
subRunLength, (nsCharType)charType);
aprocessor.SetText(runVisualText.get(), subRunLength, dir);
width = aprocessor.GetWidth();
totalWidth += width;
if (dir == NSBIDI_RTL) {
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;
const char16_t* visualRightSide;
if (dir == NSBIDI_RTL) {
// One day, son, this could all be replaced with
// mPresContext->GetBidiEngine().GetVisualIndex() ...
posResolve->visualIndex =
visualStart +
(subRunLength - (posResolve->logicalIndex + 1 - start));
// Skipping to the "left part".
visualLeftPart = text + 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 = text + 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, dir);
subWidth = aprocessor.GetWidth();
aprocessor.SetText(visualRightSide, visualLeftLength + 1, dir);
posResolve->visualLeftTwips = xOffset + subWidth;
posResolve->visualWidth = aprocessor.GetWidth() - subWidth;
}
}
}
if (dir == NSBIDI_LTR) {
xOffset += width;
}
--subRunCount;
start = lineOffset;
subRunLimit = typeLimit;
subRunLength = typeLimit - lineOffset;
} // while
if (dir == NSBIDI_RTL) {
xOffset = xEndRun;
}
visualStart += length;
} // for
if (aWidth) {
*aWidth = totalWidth;
}
return NS_OK;
}
class MOZ_STACK_CLASS nsIRenderingContextBidiProcessor final
: public nsBidiPresUtils::BidiProcessor {
public:
typedef mozilla::gfx::DrawTarget DrawTarget;
nsIRenderingContextBidiProcessor(gfxContext* aCtx,
DrawTarget* aTextRunConstructionDrawTarget,
nsFontMetrics* aFontMetrics,
const nsPoint& aPt)
: mCtx(aCtx),
mTextRunConstructionDrawTarget(aTextRunConstructionDrawTarget),
mFontMetrics(aFontMetrics),
mPt(aPt),
mText(nullptr),
mLength(0) {}
~nsIRenderingContextBidiProcessor() { mFontMetrics->SetTextRunRTL(false); }
virtual void SetText(const char16_t* aText, int32_t aLength,
nsBidiDirection aDirection) override {
mFontMetrics->SetTextRunRTL(aDirection == NSBIDI_RTL);
mText = aText;
mLength = aLength;
}
virtual nscoord GetWidth() override {
return nsLayoutUtils::AppUnitWidthOfString(mText, mLength, *mFontMetrics,
mTextRunConstructionDrawTarget);
}
virtual void DrawText(nscoord aIOffset, nscoord) override {
nsPoint pt(mPt);
if (mFontMetrics->GetVertical()) {
pt.y += aIOffset;
} else {
pt.x += aIOffset;
}
mFontMetrics->DrawString(mText, mLength, pt.x, pt.y, mCtx,
mTextRunConstructionDrawTarget);
}
private:
gfxContext* mCtx;
DrawTarget* mTextRunConstructionDrawTarget;
nsFontMetrics* mFontMetrics;
nsPoint mPt;
const char16_t* mText;
int32_t mLength;
};
nsresult nsBidiPresUtils::ProcessTextForRenderingContext(
const char16_t* aText, int32_t aLength, nsBidiLevel aBaseLevel,
nsPresContext* aPresContext, gfxContext& aRenderingContext,
DrawTarget* aTextRunConstructionDrawTarget, nsFontMetrics& aFontMetrics,
Mode aMode, nscoord aX, nscoord aY, nsBidiPositionResolve* aPosResolve,
int32_t aPosResolveCount, nscoord* aWidth) {
nsIRenderingContextBidiProcessor processor(&aRenderingContext,
aTextRunConstructionDrawTarget,
&aFontMetrics, nsPoint(aX, aY));
return ProcessText(aText, aLength, aBaseLevel, aPresContext, processor, aMode,
aPosResolve, aPosResolveCount, aWidth,
&aPresContext->GetBidiEngine());
}
/* static */
nsBidiLevel nsBidiPresUtils::BidiLevelFromStyle(ComputedStyle* aComputedStyle) {
if (aComputedStyle->StyleTextReset()->mUnicodeBidi &
NS_STYLE_UNICODE_BIDI_PLAINTEXT) {
return NSBIDI_DEFAULT_LTR;
}
if (aComputedStyle->StyleVisibility()->mDirection == NS_STYLE_DIRECTION_RTL) {
return NSBIDI_RTL;
}
return NSBIDI_LTR;
}
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