| /* |
| * Copyright (C) 2000 Lars Knoll (knoll@kde.org) |
| * Copyright (C) 2003, 2004, 2006, 2007, 2008 Apple Inc. All right reserved. |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Library General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 of the License, or (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Library General Public License for more details. |
| * |
| * You should have received a copy of the GNU Library General Public License |
| * along with this library; see the file COPYING.LIB. If not, write to |
| * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, |
| * Boston, MA 02110-1301, USA. |
| * |
| */ |
| |
| #ifndef BidiResolver_h |
| #define BidiResolver_h |
| |
| #include "platform/text/BidiCharacterRun.h" |
| #include "platform/text/BidiContext.h" |
| #include "platform/text/BidiRunList.h" |
| #include "platform/text/TextDirection.h" |
| #include "platform/wtf/Allocator.h" |
| #include "platform/wtf/HashMap.h" |
| #include "platform/wtf/Noncopyable.h" |
| #include "platform/wtf/Vector.h" |
| |
| namespace blink { |
| |
| template <class Iterator> |
| class MidpointState final { |
| DISALLOW_NEW(); |
| |
| public: |
| MidpointState() { Reset(); } |
| |
| void Reset() { |
| num_midpoints_ = 0; |
| current_midpoint_ = 0; |
| between_midpoints_ = false; |
| } |
| |
| void StartIgnoringSpaces(const Iterator& midpoint) { |
| DCHECK(!(num_midpoints_ % 2)); |
| AddMidpoint(midpoint); |
| } |
| |
| void StopIgnoringSpaces(const Iterator& midpoint) { |
| DCHECK(num_midpoints_ % 2); |
| AddMidpoint(midpoint); |
| } |
| |
| // Adding a pair of midpoints before a character will split it out into a new |
| // line box. |
| void EnsureCharacterGetsLineBox(Iterator& text_paragraph_separator) { |
| StartIgnoringSpaces(Iterator(0, |
| text_paragraph_separator.GetLineLayoutItem(), |
| text_paragraph_separator.Offset() - 1)); |
| StopIgnoringSpaces(Iterator(0, text_paragraph_separator.GetLineLayoutItem(), |
| text_paragraph_separator.Offset())); |
| } |
| |
| void CheckMidpoints(Iterator& l_break) { |
| // Check to see if our last midpoint is a start point beyond the line break. |
| // If so, shave it off the list, and shave off a trailing space if the |
| // previous end point doesn't preserve whitespace. |
| if (l_break.GetLineLayoutItem() && num_midpoints_ && |
| !(num_midpoints_ % 2)) { |
| Iterator* midpoints_iterator = midpoints_.data(); |
| Iterator& endpoint = midpoints_iterator[num_midpoints_ - 2]; |
| const Iterator& startpoint = midpoints_iterator[num_midpoints_ - 1]; |
| Iterator currpoint = endpoint; |
| while (!currpoint.AtEnd() && currpoint != startpoint && |
| currpoint != l_break) |
| currpoint.Increment(); |
| if (currpoint == l_break) { |
| // We hit the line break before the start point. Shave off the start |
| // point. |
| num_midpoints_--; |
| if (endpoint.GetLineLayoutItem().Style()->CollapseWhiteSpace() && |
| endpoint.GetLineLayoutItem().IsText()) |
| endpoint.SetOffset(endpoint.Offset() - 1); |
| } |
| } |
| } |
| |
| Vector<Iterator>& Midpoints() { return midpoints_; } |
| const unsigned& NumMidpoints() const { return num_midpoints_; } |
| const unsigned& CurrentMidpoint() const { return current_midpoint_; } |
| void IncrementCurrentMidpoint() { current_midpoint_++; } |
| const bool& BetweenMidpoints() const { return between_midpoints_; } |
| void SetBetweenMidpoints(bool between_midpoint) { |
| between_midpoints_ = between_midpoint; |
| } |
| |
| private: |
| // The goal is to reuse the line state across multiple |
| // lines so we just keep an array around for midpoints and never clear it |
| // across multiple lines. We track the number of items and position using the |
| // two other variables. |
| Vector<Iterator> midpoints_; |
| unsigned num_midpoints_; |
| unsigned current_midpoint_; |
| bool between_midpoints_; |
| |
| void AddMidpoint(const Iterator& midpoint) { |
| if (midpoints_.size() <= num_midpoints_) |
| midpoints_.Grow(num_midpoints_ + 10); |
| |
| Iterator* midpoints_iterator = midpoints_.data(); |
| midpoints_iterator[num_midpoints_++] = midpoint; |
| } |
| }; |
| |
| // The BidiStatus at a given position (typically the end of a line) can |
| // be cached and then used to restart bidi resolution at that position. |
| struct BidiStatus final { |
| DISALLOW_NEW(); |
| BidiStatus() |
| : eor(WTF::Unicode::kOtherNeutral), |
| last_strong(WTF::Unicode::kOtherNeutral), |
| last(WTF::Unicode::kOtherNeutral) {} |
| |
| // Creates a BidiStatus representing a new paragraph root with a default |
| // direction. Uses TextDirection as it only has two possibilities instead of |
| // WTF::Unicode::Direction which has 19. |
| BidiStatus(TextDirection text_direction, bool is_override) { |
| WTF::Unicode::CharDirection direction = |
| text_direction == TextDirection::kLtr ? WTF::Unicode::kLeftToRight |
| : WTF::Unicode::kRightToLeft; |
| eor = last_strong = last = direction; |
| context = BidiContext::Create(text_direction == TextDirection::kLtr ? 0 : 1, |
| direction, is_override); |
| } |
| |
| BidiStatus(WTF::Unicode::CharDirection eor_dir, |
| WTF::Unicode::CharDirection last_strong_dir, |
| WTF::Unicode::CharDirection last_dir, |
| RefPtr<BidiContext> bidi_context) |
| : eor(eor_dir), |
| last_strong(last_strong_dir), |
| last(last_dir), |
| context(std::move(bidi_context)) {} |
| |
| // Creates a BidiStatus for Isolates (RLI/LRI). |
| // The rule X5a ans X5b of UAX#9: http://unicode.org/reports/tr9/#X5a |
| static BidiStatus CreateForIsolate(TextDirection text_direction, |
| bool is_override, |
| unsigned char level) { |
| WTF::Unicode::CharDirection direction; |
| if (text_direction == TextDirection::kRtl) { |
| level = NextGreaterOddLevel(level); |
| direction = WTF::Unicode::kRightToLeft; |
| } else { |
| level = NextGreaterEvenLevel(level); |
| direction = WTF::Unicode::kLeftToRight; |
| } |
| RefPtr<BidiContext> context = |
| BidiContext::Create(level, direction, is_override, kFromStyleOrDOM); |
| |
| // This copies BidiStatus and may churn the ref on BidiContext. |
| // I doubt it matters. |
| return BidiStatus(direction, direction, direction, std::move(context)); |
| } |
| |
| WTF::Unicode::CharDirection eor; |
| WTF::Unicode::CharDirection last_strong; |
| WTF::Unicode::CharDirection last; |
| RefPtr<BidiContext> context; |
| }; |
| |
| class BidiEmbedding final { |
| DISALLOW_NEW_EXCEPT_PLACEMENT_NEW(); |
| |
| public: |
| BidiEmbedding(WTF::Unicode::CharDirection direction, |
| BidiEmbeddingSource source) |
| : direction_(direction), source_(source) {} |
| |
| WTF::Unicode::CharDirection Direction() const { return direction_; } |
| BidiEmbeddingSource Source() const { return source_; } |
| |
| private: |
| WTF::Unicode::CharDirection direction_; |
| BidiEmbeddingSource source_; |
| }; |
| |
| inline bool operator==(const BidiStatus& status1, const BidiStatus& status2) { |
| return status1.eor == status2.eor && status1.last == status2.last && |
| status1.last_strong == status2.last_strong && |
| *(status1.context) == *(status2.context); |
| } |
| |
| inline bool operator!=(const BidiStatus& status1, const BidiStatus& status2) { |
| return !(status1 == status2); |
| } |
| |
| enum VisualDirectionOverride { |
| kNoVisualOverride, |
| kVisualLeftToRightOverride, |
| kVisualRightToLeftOverride |
| }; |
| |
| class NoIsolatedRun {}; |
| |
| // BidiResolver is WebKit's implementation of the Unicode Bidi Algorithm |
| // http://unicode.org/reports/tr9 |
| template <class Iterator, class Run, class IsolatedRun = NoIsolatedRun> |
| class BidiResolver final { |
| DISALLOW_NEW(); |
| WTF_MAKE_NONCOPYABLE(BidiResolver); |
| |
| public: |
| BidiResolver() |
| : direction_(WTF::Unicode::kOtherNeutral), |
| reached_end_of_line_(false), |
| empty_run_(true), |
| nested_isolate_count_(0), |
| trailing_space_run_(0), |
| needs_trailing_space_(false) {} |
| |
| #if DCHECK_IS_ON() |
| ~BidiResolver(); |
| #endif |
| |
| const Iterator& GetPosition() const { return current_; } |
| Iterator& GetPosition() { return current_; } |
| void SetPositionIgnoringNestedIsolates(const Iterator& position) { |
| current_ = position; |
| } |
| void SetPosition(const Iterator& position, unsigned nested_isolated_count) { |
| current_ = position; |
| nested_isolate_count_ = nested_isolated_count; |
| } |
| |
| BidiContext* Context() const { return status_.context.Get(); } |
| void SetContext(RefPtr<BidiContext> c) { status_.context = std::move(c); } |
| |
| void SetLastDir(WTF::Unicode::CharDirection last_dir) { |
| status_.last = last_dir; |
| } |
| void SetLastStrongDir(WTF::Unicode::CharDirection last_strong_dir) { |
| status_.last_strong = last_strong_dir; |
| } |
| void SetEorDir(WTF::Unicode::CharDirection eor_dir) { status_.eor = eor_dir; } |
| |
| WTF::Unicode::CharDirection Dir() const { return direction_; } |
| void SetDir(WTF::Unicode::CharDirection d) { direction_ = d; } |
| |
| const BidiStatus& Status() const { return status_; } |
| void SetStatus(const BidiStatus s) { |
| DCHECK(s.context); |
| status_ = s; |
| paragraph_directionality_ = s.context->Dir() == WTF::Unicode::kLeftToRight |
| ? TextDirection::kLtr |
| : TextDirection::kRtl; |
| } |
| |
| MidpointState<Iterator>& GetMidpointState() { return midpoint_state_; } |
| |
| // The current algorithm handles nested isolates one layer of nesting at a |
| // time. But when we layout each isolated span, we will walk into (and |
| // ignore) all child isolated spans. |
| void EnterIsolate() { nested_isolate_count_++; } |
| void ExitIsolate() { |
| DCHECK_GE(nested_isolate_count_, 1u); |
| nested_isolate_count_--; |
| } |
| bool InIsolate() const { return nested_isolate_count_; } |
| |
| void Embed(WTF::Unicode::CharDirection, BidiEmbeddingSource); |
| bool CommitExplicitEmbedding(BidiRunList<Run>&); |
| |
| void CreateBidiRunsForLine(const Iterator& end, |
| VisualDirectionOverride = kNoVisualOverride, |
| bool hard_line_break = false, |
| bool reorder_runs = true); |
| |
| BidiRunList<Run>& Runs() { return runs_; } |
| |
| // FIXME: This used to be part of deleteRuns() but was a layering violation. |
| // It's unclear if this is still needed. |
| void MarkCurrentRunEmpty() { empty_run_ = true; } |
| |
| Vector<IsolatedRun>& IsolatedRuns() { return isolated_runs_; } |
| |
| bool IsEndOfLine(const Iterator& end) { |
| return current_ == end || current_.AtEnd(); |
| } |
| |
| TextDirection DetermineParagraphDirectionality( |
| bool* has_strong_directionality = 0) { |
| bool break_on_paragraph = true; |
| return DetermineDirectionalityInternal(break_on_paragraph, |
| has_strong_directionality); |
| } |
| TextDirection DetermineDirectionality(bool* has_strong_directionality = 0) { |
| bool break_on_paragraph = false; |
| return DetermineDirectionalityInternal(break_on_paragraph, |
| has_strong_directionality); |
| } |
| |
| void SetMidpointStateForIsolatedRun(Run&, const MidpointState<Iterator>&); |
| MidpointState<Iterator> MidpointStateForIsolatedRun(Run&); |
| |
| Iterator EndOfLine() const { return end_of_line_; } |
| |
| void SetNeedsTrailingSpace(bool value) { needs_trailing_space_ = value; } |
| Run* TrailingSpaceRun() const { return trailing_space_run_; } |
| |
| protected: |
| void Increment() { current_.Increment(); } |
| // FIXME: Instead of InlineBidiResolvers subclassing this method, we should |
| // pass in some sort of Traits object which knows how to create runs for |
| // appending. |
| void AppendRun(BidiRunList<Run>&); |
| |
| Run* AddTrailingRun(BidiRunList<Run>&, |
| int, |
| int, |
| Run*, |
| BidiContext*, |
| TextDirection) const { |
| return 0; |
| } |
| Iterator current_; |
| // sor and eor are "start of run" and "end of run" respectively and correpond |
| // to abreviations used in UBA spec: http://unicode.org/reports/tr9/#BD7 |
| Iterator sor_; // Points to the first character in the current run. |
| Iterator eor_; // Points to the last character in the current run. |
| Iterator last_; |
| BidiStatus status_; |
| WTF::Unicode::CharDirection direction_; |
| // m_endOfRunAtEndOfLine is "the position last eor in the end of line" |
| Iterator end_of_run_at_end_of_line_; |
| Iterator end_of_line_; |
| bool reached_end_of_line_; |
| Iterator last_before_et_; // Before a EuropeanNumberTerminator |
| bool empty_run_; |
| |
| // FIXME: This should not belong to the resolver, but rather be passed |
| // into createBidiRunsForLine by the caller. |
| BidiRunList<Run> runs_; |
| |
| MidpointState<Iterator> midpoint_state_; |
| |
| unsigned nested_isolate_count_; |
| Vector<IsolatedRun> isolated_runs_; |
| Run* trailing_space_run_; |
| bool needs_trailing_space_; |
| TextDirection paragraph_directionality_; |
| |
| private: |
| void RaiseExplicitEmbeddingLevel(BidiRunList<Run>&, |
| WTF::Unicode::CharDirection from, |
| WTF::Unicode::CharDirection to); |
| void LowerExplicitEmbeddingLevel(BidiRunList<Run>&, |
| WTF::Unicode::CharDirection from); |
| void CheckDirectionInLowerRaiseEmbeddingLevel(); |
| |
| void UpdateStatusLastFromCurrentDirection(WTF::Unicode::CharDirection); |
| void ReorderRunsFromLevels(BidiRunList<Run>&) const; |
| |
| bool NeedsTrailingSpace(BidiRunList<Run>&) { return needs_trailing_space_; } |
| int FindFirstTrailingSpaceAtRun(Run*) { return 0; } |
| // http://www.unicode.org/reports/tr9/#L1 |
| void ComputeTrailingSpace(BidiRunList<Run>&); |
| |
| TextDirection DetermineDirectionalityInternal( |
| bool break_on_paragraph, |
| bool* has_strong_directionality); |
| |
| Vector<BidiEmbedding, 8> current_explicit_embedding_sequence_; |
| HashMap<Run*, MidpointState<Iterator>> midpoint_state_for_isolated_run_; |
| }; |
| |
| #if DCHECK_IS_ON() |
| template <class Iterator, class Run, class IsolatedRun> |
| BidiResolver<Iterator, Run, IsolatedRun>::~BidiResolver() { |
| // The owner of this resolver should have handled the isolated runs. |
| DCHECK(isolated_runs_.IsEmpty()); |
| DCHECK(!runs_.RunCount()); |
| } |
| #endif |
| |
| template <class Iterator, class Run, class IsolatedRun> |
| void BidiResolver<Iterator, Run, IsolatedRun>::AppendRun( |
| BidiRunList<Run>& runs) { |
| if (!empty_run_ && !eor_.AtEnd()) { |
| unsigned start_offset = sor_.Offset(); |
| unsigned end_offset = eor_.Offset(); |
| |
| if (!end_of_run_at_end_of_line_.AtEnd() && |
| end_offset >= end_of_run_at_end_of_line_.Offset()) { |
| reached_end_of_line_ = true; |
| end_offset = end_of_run_at_end_of_line_.Offset(); |
| } |
| |
| // m_eor and m_endOfRunAtEndOfLine are inclusive while BidiRun's stop is |
| // exclusive so offset needs to be increased by one. |
| end_offset += 1; |
| |
| // Append BidiRun objects, at most 64K chars at a time, until all |
| // text between |startOffset| and |endOffset| is represented. |
| while (start_offset < end_offset) { |
| unsigned end = end_offset; |
| const int kLimit = |
| USHRT_MAX; // InlineTextBox stores text length as unsigned short. |
| if (end - start_offset > kLimit) |
| end = start_offset + kLimit; |
| runs.AddRun(new Run(Context()->Override(), Context()->Level(), |
| start_offset, end, direction_, Context()->Dir())); |
| start_offset = end; |
| } |
| |
| eor_.Increment(); |
| sor_ = eor_; |
| } |
| |
| direction_ = WTF::Unicode::kOtherNeutral; |
| status_.eor = WTF::Unicode::kOtherNeutral; |
| } |
| |
| template <class Iterator, class Run, class IsolatedRun> |
| void BidiResolver<Iterator, Run, IsolatedRun>::Embed( |
| WTF::Unicode::CharDirection dir, |
| BidiEmbeddingSource source) { |
| // Isolated spans compute base directionality during their own UBA run. |
| // Do not insert fake embed characters once we enter an isolated span. |
| DCHECK(!InIsolate()); |
| using namespace WTF::Unicode; |
| |
| DCHECK(dir == kPopDirectionalFormat || dir == kLeftToRightEmbedding || |
| dir == kLeftToRightOverride || dir == kRightToLeftEmbedding || |
| dir == kRightToLeftOverride); |
| current_explicit_embedding_sequence_.push_back(BidiEmbedding(dir, source)); |
| } |
| |
| template <class Iterator, class Run, class IsolatedRun> |
| void BidiResolver<Iterator, Run, IsolatedRun>:: |
| CheckDirectionInLowerRaiseEmbeddingLevel() { |
| using namespace WTF::Unicode; |
| |
| DCHECK(status_.eor != kOtherNeutral || eor_.AtEnd()); |
| DCHECK_NE(status_.last, kNonSpacingMark); |
| DCHECK_NE(status_.last, kBoundaryNeutral); |
| DCHECK_NE(status_.last, kRightToLeftEmbedding); |
| DCHECK_NE(status_.last, kLeftToRightEmbedding); |
| DCHECK_NE(status_.last, kRightToLeftOverride); |
| DCHECK_NE(status_.last, kLeftToRightOverride); |
| DCHECK_NE(status_.last, kPopDirectionalFormat); |
| if (direction_ == kOtherNeutral) |
| direction_ = |
| status_.last_strong == kLeftToRight ? kLeftToRight : kRightToLeft; |
| } |
| |
| template <class Iterator, class Run, class IsolatedRun> |
| void BidiResolver<Iterator, Run, IsolatedRun>::LowerExplicitEmbeddingLevel( |
| BidiRunList<Run>& runs, |
| WTF::Unicode::CharDirection from) { |
| using namespace WTF::Unicode; |
| |
| if (!empty_run_ && eor_ != last_) { |
| CheckDirectionInLowerRaiseEmbeddingLevel(); |
| // bidi.sor ... bidi.eor ... bidi.last eor; need to append the |
| // bidi.sor-bidi.eor run or extend it through bidi.last |
| if (from == kLeftToRight) { |
| // bidi.sor ... bidi.eor ... bidi.last L |
| if (status_.eor == kEuropeanNumber) { |
| if (status_.last_strong != kLeftToRight) { |
| direction_ = kEuropeanNumber; |
| AppendRun(runs); |
| } |
| } else if (status_.eor == kArabicNumber) { |
| direction_ = kArabicNumber; |
| AppendRun(runs); |
| } else if (status_.last_strong != kLeftToRight) { |
| AppendRun(runs); |
| direction_ = kLeftToRight; |
| } |
| } else if (status_.eor == kEuropeanNumber || status_.eor == kArabicNumber || |
| status_.last_strong == kLeftToRight) { |
| AppendRun(runs); |
| direction_ = kRightToLeft; |
| } |
| eor_ = last_; |
| } |
| |
| AppendRun(runs); |
| empty_run_ = true; |
| |
| // sor for the new run is determined by the higher level (rule X10) |
| SetLastDir(from); |
| SetLastStrongDir(from); |
| eor_ = Iterator(); |
| } |
| |
| template <class Iterator, class Run, class IsolatedRun> |
| void BidiResolver<Iterator, Run, IsolatedRun>::RaiseExplicitEmbeddingLevel( |
| BidiRunList<Run>& runs, |
| WTF::Unicode::CharDirection from, |
| WTF::Unicode::CharDirection to) { |
| using namespace WTF::Unicode; |
| |
| if (!empty_run_ && eor_ != last_) { |
| CheckDirectionInLowerRaiseEmbeddingLevel(); |
| // bidi.sor ... bidi.eor ... bidi.last eor; need to append the |
| // bidi.sor-bidi.eor run or extend it through bidi.last |
| if (to == kLeftToRight) { |
| // bidi.sor ... bidi.eor ... bidi.last L |
| if (status_.eor == kEuropeanNumber) { |
| if (status_.last_strong != kLeftToRight) { |
| direction_ = kEuropeanNumber; |
| AppendRun(runs); |
| } |
| } else if (status_.eor == kArabicNumber) { |
| direction_ = kArabicNumber; |
| AppendRun(runs); |
| } else if (status_.last_strong != kLeftToRight && from == kLeftToRight) { |
| AppendRun(runs); |
| direction_ = kLeftToRight; |
| } |
| } else if (status_.eor == kArabicNumber || |
| (status_.eor == kEuropeanNumber && |
| (status_.last_strong != kLeftToRight || |
| from == kRightToLeft)) || |
| (status_.eor != kEuropeanNumber && |
| status_.last_strong == kLeftToRight && from == kRightToLeft)) { |
| AppendRun(runs); |
| direction_ = kRightToLeft; |
| } |
| eor_ = last_; |
| } |
| |
| AppendRun(runs); |
| empty_run_ = true; |
| |
| SetLastDir(to); |
| SetLastStrongDir(to); |
| eor_ = Iterator(); |
| } |
| |
| template <class Iterator, class Run, class IsolatedRun> |
| void BidiResolver<Iterator, Run, IsolatedRun>::ComputeTrailingSpace( |
| BidiRunList<Run>& runs) { |
| DCHECK(runs.RunCount()); |
| |
| Run* trailing_space_run = runs.LogicallyLastRun(); |
| |
| int first_space = FindFirstTrailingSpaceAtRun(trailing_space_run); |
| if (first_space == trailing_space_run->Stop()) |
| return; |
| |
| bool should_reorder = |
| trailing_space_run != (paragraph_directionality_ == TextDirection::kLtr |
| ? runs.LastRun() |
| : runs.FirstRun()); |
| if (first_space != trailing_space_run->Start()) { |
| BidiContext* base_context = Context(); |
| while (BidiContext* parent = base_context->Parent()) |
| base_context = parent; |
| |
| trailing_space_run_ = AddTrailingRun( |
| runs, first_space, trailing_space_run->stop_, trailing_space_run, |
| base_context, paragraph_directionality_); |
| DCHECK(trailing_space_run_); |
| trailing_space_run->stop_ = first_space; |
| return; |
| } |
| if (!should_reorder) { |
| trailing_space_run_ = trailing_space_run; |
| return; |
| } |
| |
| // Apply L1 rule. |
| if (paragraph_directionality_ == TextDirection::kLtr) { |
| runs.MoveRunToEnd(trailing_space_run); |
| trailing_space_run->level_ = 0; |
| } else { |
| runs.MoveRunToBeginning(trailing_space_run); |
| trailing_space_run->level_ = 1; |
| } |
| trailing_space_run_ = trailing_space_run; |
| } |
| |
| template <class Iterator, class Run, class IsolatedRun> |
| bool BidiResolver<Iterator, Run, IsolatedRun>::CommitExplicitEmbedding( |
| BidiRunList<Run>& runs) { |
| // When we're "inIsolate()" we're resolving the parent context which |
| // ignores (skips over) the isolated content, including embedding levels. |
| // We should never accrue embedding levels while skipping over isolated |
| // content. |
| DCHECK(!InIsolate() || current_explicit_embedding_sequence_.IsEmpty()); |
| |
| using namespace WTF::Unicode; |
| |
| unsigned char from_level = Context()->Level(); |
| RefPtr<BidiContext> to_context = Context(); |
| |
| for (size_t i = 0; i < current_explicit_embedding_sequence_.size(); ++i) { |
| BidiEmbedding embedding = current_explicit_embedding_sequence_[i]; |
| if (embedding.Direction() == kPopDirectionalFormat) { |
| if (BidiContext* parent_context = to_context->Parent()) |
| to_context = parent_context; |
| } else { |
| CharDirection direction = |
| (embedding.Direction() == kRightToLeftEmbedding || |
| embedding.Direction() == kRightToLeftOverride) |
| ? kRightToLeft |
| : kLeftToRight; |
| bool override = embedding.Direction() == kLeftToRightOverride || |
| embedding.Direction() == kRightToLeftOverride; |
| unsigned char level = to_context->Level(); |
| if (direction == kRightToLeft) |
| level = NextGreaterOddLevel(level); |
| else |
| level = NextGreaterEvenLevel(level); |
| if (level < BidiContext::kMaxLevel) |
| to_context = BidiContext::Create(level, direction, override, |
| embedding.Source(), to_context.Get()); |
| } |
| } |
| |
| unsigned char to_level = to_context->Level(); |
| |
| if (to_level > from_level) |
| RaiseExplicitEmbeddingLevel(runs, |
| from_level % 2 ? kRightToLeft : kLeftToRight, |
| to_level % 2 ? kRightToLeft : kLeftToRight); |
| else if (to_level < from_level) |
| LowerExplicitEmbeddingLevel(runs, |
| from_level % 2 ? kRightToLeft : kLeftToRight); |
| |
| SetContext(to_context); |
| |
| current_explicit_embedding_sequence_.clear(); |
| |
| return from_level != to_level; |
| } |
| |
| template <class Iterator, class Run, class IsolatedRun> |
| inline void |
| BidiResolver<Iterator, Run, IsolatedRun>::UpdateStatusLastFromCurrentDirection( |
| WTF::Unicode::CharDirection dir_current) { |
| using namespace WTF::Unicode; |
| switch (dir_current) { |
| case kEuropeanNumberTerminator: |
| if (status_.last != kEuropeanNumber) |
| status_.last = kEuropeanNumberTerminator; |
| break; |
| case kEuropeanNumberSeparator: |
| case kCommonNumberSeparator: |
| case kSegmentSeparator: |
| case kWhiteSpaceNeutral: |
| case kOtherNeutral: |
| switch (status_.last) { |
| case kLeftToRight: |
| case kRightToLeft: |
| case kRightToLeftArabic: |
| case kEuropeanNumber: |
| case kArabicNumber: |
| status_.last = dir_current; |
| break; |
| default: |
| status_.last = kOtherNeutral; |
| } |
| break; |
| case kNonSpacingMark: |
| case kBoundaryNeutral: |
| case kRightToLeftEmbedding: |
| case kLeftToRightEmbedding: |
| case kRightToLeftOverride: |
| case kLeftToRightOverride: |
| case kPopDirectionalFormat: |
| // ignore these |
| break; |
| case kEuropeanNumber: |
| // fall through |
| default: |
| status_.last = dir_current; |
| } |
| } |
| |
| template <class Iterator, class Run, class IsolatedRun> |
| inline void BidiResolver<Iterator, Run, IsolatedRun>::ReorderRunsFromLevels( |
| BidiRunList<Run>& runs) const { |
| unsigned char level_low = BidiContext::kMaxLevel; |
| unsigned char level_high = 0; |
| for (Run* run = runs.FirstRun(); run; run = run->Next()) { |
| level_high = std::max(run->Level(), level_high); |
| level_low = std::min(run->Level(), level_low); |
| } |
| |
| // This implements reordering of the line (L2 according to Bidi spec): |
| // http://unicode.org/reports/tr9/#L2 |
| // L2. From the highest level found in the text to the lowest odd level on |
| // each line, reverse any contiguous sequence of characters that are at that |
| // level or higher. |
| |
| // Reversing is only done up to the lowest odd level. |
| if (!(level_low % 2)) |
| level_low++; |
| |
| unsigned count = runs.RunCount() - 1; |
| |
| while (level_high >= level_low) { |
| unsigned i = 0; |
| Run* run = runs.FirstRun(); |
| while (i < count) { |
| for (; i < count && run && run->Level() < level_high; i++) |
| run = run->Next(); |
| unsigned start = i; |
| for (; i <= count && run && run->Level() >= level_high; i++) |
| run = run->Next(); |
| unsigned end = i - 1; |
| runs.ReverseRuns(start, end); |
| } |
| level_high--; |
| } |
| } |
| |
| template <class Iterator, class Run, class IsolatedRun> |
| TextDirection |
| BidiResolver<Iterator, Run, IsolatedRun>::DetermineDirectionalityInternal( |
| bool break_on_paragraph, |
| bool* has_strong_directionality) { |
| while (!current_.AtEnd()) { |
| if (InIsolate()) { |
| Increment(); |
| continue; |
| } |
| if (break_on_paragraph && current_.AtParagraphSeparator()) |
| break; |
| UChar32 current = current_.Current(); |
| if (UNLIKELY(U16_IS_SURROGATE(current))) { |
| Increment(); |
| // If this not the high part of the surrogate pair, then drop it and move |
| // to the next. |
| if (!U16_IS_SURROGATE_LEAD(current)) |
| continue; |
| UChar high = static_cast<UChar>(current); |
| if (current_.AtEnd()) |
| continue; |
| UChar low = current_.Current(); |
| // Verify the low part. If invalid, then assume an invalid surrogate pair |
| // and retry. |
| if (!U16_IS_TRAIL(low)) |
| continue; |
| current = U16_GET_SUPPLEMENTARY(high, low); |
| } |
| WTF::Unicode::CharDirection char_direction = |
| WTF::Unicode::Direction(current); |
| if (char_direction == WTF::Unicode::kLeftToRight) { |
| if (has_strong_directionality) |
| *has_strong_directionality = true; |
| return TextDirection::kLtr; |
| } |
| if (char_direction == WTF::Unicode::kRightToLeft || |
| char_direction == WTF::Unicode::kRightToLeftArabic) { |
| if (has_strong_directionality) |
| *has_strong_directionality = true; |
| return TextDirection::kRtl; |
| } |
| Increment(); |
| } |
| if (has_strong_directionality) |
| *has_strong_directionality = false; |
| return TextDirection::kLtr; |
| } |
| |
| inline TextDirection DirectionForCharacter(UChar32 character) { |
| WTF::Unicode::CharDirection char_direction = |
| WTF::Unicode::Direction(character); |
| if (char_direction == WTF::Unicode::kRightToLeft || |
| char_direction == WTF::Unicode::kRightToLeftArabic) |
| return TextDirection::kRtl; |
| return TextDirection::kLtr; |
| } |
| |
| template <class Iterator, class Run, class IsolatedRun> |
| void BidiResolver<Iterator, Run, IsolatedRun>::CreateBidiRunsForLine( |
| const Iterator& end, |
| VisualDirectionOverride override, |
| bool hard_line_break, |
| bool reorder_runs) { |
| using namespace WTF::Unicode; |
| |
| DCHECK_EQ(direction_, kOtherNeutral); |
| trailing_space_run_ = 0; |
| |
| end_of_line_ = end; |
| |
| if (override != kNoVisualOverride) { |
| empty_run_ = false; |
| sor_ = current_; |
| eor_ = Iterator(); |
| while (current_ != end && !current_.AtEnd()) { |
| eor_ = current_; |
| Increment(); |
| } |
| direction_ = |
| override == kVisualLeftToRightOverride ? kLeftToRight : kRightToLeft; |
| AppendRun(runs_); |
| runs_.SetLogicallyLastRun(runs_.LastRun()); |
| if (override == kVisualRightToLeftOverride && runs_.RunCount()) |
| runs_.ReverseRuns(0, runs_.RunCount() - 1); |
| return; |
| } |
| |
| empty_run_ = true; |
| |
| eor_ = Iterator(); |
| |
| last_ = current_; |
| bool last_line_ended = false; |
| BidiResolver<Iterator, Run, IsolatedRun> state_at_end; |
| |
| while (true) { |
| if (InIsolate() && empty_run_) { |
| sor_ = current_; |
| empty_run_ = false; |
| } |
| |
| if (!last_line_ended && IsEndOfLine(end)) { |
| if (empty_run_) |
| break; |
| |
| state_at_end.status_ = status_; |
| state_at_end.sor_ = sor_; |
| state_at_end.eor_ = eor_; |
| state_at_end.last_ = last_; |
| state_at_end.reached_end_of_line_ = reached_end_of_line_; |
| state_at_end.last_before_et_ = last_before_et_; |
| state_at_end.empty_run_ = empty_run_; |
| end_of_run_at_end_of_line_ = last_; |
| last_line_ended = true; |
| } |
| CharDirection dir_current; |
| if (last_line_ended && (hard_line_break || current_.AtEnd())) { |
| BidiContext* c = Context(); |
| if (hard_line_break) { |
| // A deviation from the Unicode Bidi Algorithm in order to match |
| // WinIE and user expectations: hard line breaks reset bidi state |
| // coming from unicode bidi control characters, but not those from |
| // DOM nodes with specified directionality |
| state_at_end.SetContext(c->CopyStackRemovingUnicodeEmbeddingContexts()); |
| |
| dir_current = state_at_end.Context()->Dir(); |
| state_at_end.SetEorDir(dir_current); |
| state_at_end.SetLastDir(dir_current); |
| state_at_end.SetLastStrongDir(dir_current); |
| } else { |
| while (c->Parent()) |
| c = c->Parent(); |
| dir_current = c->Dir(); |
| } |
| } else { |
| dir_current = current_.Direction(); |
| if (Context()->Override() && dir_current != kRightToLeftEmbedding && |
| dir_current != kLeftToRightEmbedding && |
| dir_current != kRightToLeftOverride && |
| dir_current != kLeftToRightOverride && |
| dir_current != kPopDirectionalFormat) |
| dir_current = Context()->Dir(); |
| else if (dir_current == kNonSpacingMark) |
| dir_current = status_.last; |
| } |
| |
| // We ignore all character directionality while in unicode-bidi: isolate |
| // spans. We'll handle ordering the isolated characters in a second pass. |
| if (InIsolate()) |
| dir_current = kOtherNeutral; |
| |
| DCHECK(status_.eor != kOtherNeutral || eor_.AtEnd()); |
| switch (dir_current) { |
| // embedding and overrides (X1-X9 in the Bidi specs) |
| case kRightToLeftEmbedding: |
| case kLeftToRightEmbedding: |
| case kRightToLeftOverride: |
| case kLeftToRightOverride: |
| case kPopDirectionalFormat: |
| Embed(dir_current, kFromUnicode); |
| CommitExplicitEmbedding(runs_); |
| break; |
| |
| // strong types |
| case kLeftToRight: |
| switch (status_.last) { |
| case kRightToLeft: |
| case kRightToLeftArabic: |
| case kEuropeanNumber: |
| case kArabicNumber: |
| if (status_.last != kEuropeanNumber || |
| status_.last_strong != kLeftToRight) |
| AppendRun(runs_); |
| break; |
| case kLeftToRight: |
| break; |
| case kEuropeanNumberSeparator: |
| case kEuropeanNumberTerminator: |
| case kCommonNumberSeparator: |
| case kBoundaryNeutral: |
| case kBlockSeparator: |
| case kSegmentSeparator: |
| case kWhiteSpaceNeutral: |
| case kOtherNeutral: |
| if (status_.eor == kEuropeanNumber) { |
| if (status_.last_strong != kLeftToRight) { |
| // the numbers need to be on a higher embedding level, so let's |
| // close that run |
| direction_ = kEuropeanNumber; |
| AppendRun(runs_); |
| if (Context()->Dir() != kLeftToRight) { |
| // the neutrals take the embedding direction, which is R |
| eor_ = last_; |
| direction_ = kRightToLeft; |
| AppendRun(runs_); |
| } |
| } |
| } else if (status_.eor == kArabicNumber) { |
| // Arabic numbers are always on a higher embedding level, so let's |
| // close that run |
| direction_ = kArabicNumber; |
| AppendRun(runs_); |
| if (Context()->Dir() != kLeftToRight) { |
| // the neutrals take the embedding direction, which is R |
| eor_ = last_; |
| direction_ = kRightToLeft; |
| AppendRun(runs_); |
| } |
| } else if (status_.last_strong != kLeftToRight) { |
| // last stuff takes embedding dir |
| if (Context()->Dir() == kRightToLeft) { |
| eor_ = last_; |
| direction_ = kRightToLeft; |
| } |
| AppendRun(runs_); |
| } |
| default: |
| break; |
| } |
| eor_ = current_; |
| status_.eor = kLeftToRight; |
| status_.last_strong = kLeftToRight; |
| direction_ = kLeftToRight; |
| break; |
| case kRightToLeftArabic: |
| case kRightToLeft: |
| switch (status_.last) { |
| case kLeftToRight: |
| case kEuropeanNumber: |
| case kArabicNumber: |
| AppendRun(runs_); |
| case kRightToLeft: |
| case kRightToLeftArabic: |
| break; |
| case kEuropeanNumberSeparator: |
| case kEuropeanNumberTerminator: |
| case kCommonNumberSeparator: |
| case kBoundaryNeutral: |
| case kBlockSeparator: |
| case kSegmentSeparator: |
| case kWhiteSpaceNeutral: |
| case kOtherNeutral: |
| if (status_.eor == kEuropeanNumber) { |
| if (status_.last_strong == kLeftToRight && |
| Context()->Dir() == kLeftToRight) |
| eor_ = last_; |
| AppendRun(runs_); |
| } else if (status_.eor == kArabicNumber) { |
| AppendRun(runs_); |
| } else if (status_.last_strong == kLeftToRight) { |
| if (Context()->Dir() == kLeftToRight) |
| eor_ = last_; |
| AppendRun(runs_); |
| } |
| default: |
| break; |
| } |
| eor_ = current_; |
| status_.eor = kRightToLeft; |
| status_.last_strong = dir_current; |
| direction_ = kRightToLeft; |
| break; |
| |
| // weak types: |
| |
| case kEuropeanNumber: |
| if (status_.last_strong != kRightToLeftArabic) { |
| // if last strong was AL change EN to AN |
| switch (status_.last) { |
| case kEuropeanNumber: |
| case kLeftToRight: |
| break; |
| case kRightToLeft: |
| case kRightToLeftArabic: |
| case kArabicNumber: |
| eor_ = last_; |
| AppendRun(runs_); |
| direction_ = kEuropeanNumber; |
| break; |
| case kEuropeanNumberSeparator: |
| case kCommonNumberSeparator: |
| if (status_.eor == kEuropeanNumber) |
| break; |
| case kEuropeanNumberTerminator: |
| case kBoundaryNeutral: |
| case kBlockSeparator: |
| case kSegmentSeparator: |
| case kWhiteSpaceNeutral: |
| case kOtherNeutral: |
| if (status_.eor == kEuropeanNumber) { |
| if (status_.last_strong == kRightToLeft) { |
| // ENs on both sides behave like Rs, so the neutrals should be |
| // R. Terminate the EN run. |
| AppendRun(runs_); |
| // Make an R run. |
| eor_ = status_.last == kEuropeanNumberTerminator |
| ? last_before_et_ |
| : last_; |
| direction_ = kRightToLeft; |
| AppendRun(runs_); |
| // Begin a new EN run. |
| direction_ = kEuropeanNumber; |
| } |
| } else if (status_.eor == kArabicNumber) { |
| // Terminate the AN run. |
| AppendRun(runs_); |
| if (status_.last_strong == kRightToLeft || |
| Context()->Dir() == kRightToLeft) { |
| // Make an R run. |
| eor_ = status_.last == kEuropeanNumberTerminator |
| ? last_before_et_ |
| : last_; |
| direction_ = kRightToLeft; |
| AppendRun(runs_); |
| // Begin a new EN run. |
| direction_ = kEuropeanNumber; |
| } |
| } else if (status_.last_strong == kRightToLeft) { |
| // Extend the R run to include the neutrals. |
| eor_ = status_.last == kEuropeanNumberTerminator |
| ? last_before_et_ |
| : last_; |
| direction_ = kRightToLeft; |
| AppendRun(runs_); |
| // Begin a new EN run. |
| direction_ = kEuropeanNumber; |
| } |
| default: |
| break; |
| } |
| eor_ = current_; |
| status_.eor = kEuropeanNumber; |
| if (direction_ == kOtherNeutral) |
| direction_ = kLeftToRight; |
| break; |
| } |
| case kArabicNumber: |
| dir_current = kArabicNumber; |
| switch (status_.last) { |
| case kLeftToRight: |
| if (Context()->Dir() == kLeftToRight) |
| AppendRun(runs_); |
| break; |
| case kArabicNumber: |
| break; |
| case kRightToLeft: |
| case kRightToLeftArabic: |
| case kEuropeanNumber: |
| eor_ = last_; |
| AppendRun(runs_); |
| break; |
| case kCommonNumberSeparator: |
| if (status_.eor == kArabicNumber) |
| break; |
| case kEuropeanNumberSeparator: |
| case kEuropeanNumberTerminator: |
| case kBoundaryNeutral: |
| case kBlockSeparator: |
| case kSegmentSeparator: |
| case kWhiteSpaceNeutral: |
| case kOtherNeutral: |
| if (status_.eor == kArabicNumber || |
| (status_.eor == kEuropeanNumber && |
| (status_.last_strong == kRightToLeft || |
| Context()->Dir() == kRightToLeft)) || |
| (status_.eor != kEuropeanNumber && |
| status_.last_strong == kLeftToRight && |
| Context()->Dir() == kRightToLeft)) { |
| // Terminate the run before the neutrals. |
| AppendRun(runs_); |
| // Begin an R run for the neutrals. |
| direction_ = kRightToLeft; |
| } else if (direction_ == kOtherNeutral) { |
| direction_ = status_.last_strong == kLeftToRight ? kLeftToRight |
| : kRightToLeft; |
| } |
| eor_ = last_; |
| AppendRun(runs_); |
| default: |
| break; |
| } |
| eor_ = current_; |
| status_.eor = kArabicNumber; |
| if (direction_ == kOtherNeutral) |
| direction_ = kArabicNumber; |
| break; |
| case kEuropeanNumberSeparator: |
| case kCommonNumberSeparator: |
| break; |
| case kEuropeanNumberTerminator: |
| if (status_.last == kEuropeanNumber) { |
| dir_current = kEuropeanNumber; |
| eor_ = current_; |
| status_.eor = dir_current; |
| } else if (status_.last != kEuropeanNumberTerminator) { |
| last_before_et_ = empty_run_ ? eor_ : last_; |
| } |
| break; |
| |
| // boundary neutrals should be ignored |
| case kBoundaryNeutral: |
| if (eor_ == last_) |
| eor_ = current_; |
| break; |
| // neutrals |
| case kBlockSeparator: |
| // ### what do we do with newline and paragraph seperators that come to |
| // here? |
| break; |
| case kSegmentSeparator: |
| // ### implement rule L1 |
| break; |
| case kWhiteSpaceNeutral: |
| break; |
| case kOtherNeutral: |
| break; |
| default: |
| break; |
| } |
| |
| if (last_line_ended && eor_ == current_) { |
| if (!reached_end_of_line_) { |
| eor_ = end_of_run_at_end_of_line_; |
| switch (status_.eor) { |
| case kLeftToRight: |
| case kRightToLeft: |
| case kArabicNumber: |
| direction_ = status_.eor; |
| break; |
| case kEuropeanNumber: |
| direction_ = status_.last_strong == kLeftToRight ? kLeftToRight |
| : kEuropeanNumber; |
| break; |
| default: |
| NOTREACHED(); |
| } |
| AppendRun(runs_); |
| } |
| current_ = end; |
| status_ = state_at_end.status_; |
| sor_ = state_at_end.sor_; |
| eor_ = state_at_end.eor_; |
| last_ = state_at_end.last_; |
| reached_end_of_line_ = state_at_end.reached_end_of_line_; |
| last_before_et_ = state_at_end.last_before_et_; |
| empty_run_ = state_at_end.empty_run_; |
| direction_ = kOtherNeutral; |
| break; |
| } |
| |
| UpdateStatusLastFromCurrentDirection(dir_current); |
| last_ = current_; |
| |
| if (empty_run_) { |
| sor_ = current_; |
| empty_run_ = false; |
| } |
| |
| Increment(); |
| if (!current_explicit_embedding_sequence_.IsEmpty()) { |
| bool committed = CommitExplicitEmbedding(runs_); |
| if (committed && last_line_ended) { |
| current_ = end; |
| status_ = state_at_end.status_; |
| sor_ = state_at_end.sor_; |
| eor_ = state_at_end.eor_; |
| last_ = state_at_end.last_; |
| reached_end_of_line_ = state_at_end.reached_end_of_line_; |
| last_before_et_ = state_at_end.last_before_et_; |
| empty_run_ = state_at_end.empty_run_; |
| direction_ = kOtherNeutral; |
| break; |
| } |
| } |
| } |
| |
| runs_.SetLogicallyLastRun(runs_.LastRun()); |
| if (reorder_runs) |
| ReorderRunsFromLevels(runs_); |
| end_of_run_at_end_of_line_ = Iterator(); |
| end_of_line_ = Iterator(); |
| |
| if (!hard_line_break && runs_.RunCount() && NeedsTrailingSpace(runs_)) { |
| ComputeTrailingSpace(runs_); |
| } |
| } |
| |
| template <class Iterator, class Run, class IsolatedRun> |
| void BidiResolver<Iterator, Run, IsolatedRun>::SetMidpointStateForIsolatedRun( |
| Run& run, |
| const MidpointState<Iterator>& midpoint) { |
| DCHECK(!midpoint_state_for_isolated_run_.Contains(&run)); |
| midpoint_state_for_isolated_run_.insert(&run, midpoint); |
| } |
| |
| template <class Iterator, class Run, class IsolatedRun> |
| MidpointState<Iterator> |
| BidiResolver<Iterator, Run, IsolatedRun>::MidpointStateForIsolatedRun( |
| Run& run) { |
| return midpoint_state_for_isolated_run_.Take(&run); |
| } |
| |
| } // namespace blink |
| |
| #endif // BidiResolver_h |
