1 //===--- ContinuationIndenter.cpp - Format C++ code -----------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 ///
10 /// \file
11 /// \brief This file implements the continuation indenter.
12 ///
13 //===----------------------------------------------------------------------===//
14 
15 #include "BreakableToken.h"
16 #include "ContinuationIndenter.h"
17 #include "WhitespaceManager.h"
18 #include "clang/Basic/OperatorPrecedence.h"
19 #include "clang/Basic/SourceManager.h"
20 #include "clang/Format/Format.h"
21 #include "llvm/Support/Debug.h"
22 #include <string>
23 
24 #define DEBUG_TYPE "format-formatter"
25 
26 namespace clang {
27 namespace format {
28 
29 // Returns the length of everything up to the first possible line break after
30 // the ), ], } or > matching \c Tok.
31 static unsigned getLengthToMatchingParen(const FormatToken &Tok) {
32   if (!Tok.MatchingParen)
33     return 0;
34   FormatToken *End = Tok.MatchingParen;
35   while (End->Next && !End->Next->CanBreakBefore) {
36     End = End->Next;
37   }
38   return End->TotalLength - Tok.TotalLength + 1;
39 }
40 
41 // Returns \c true if \c Tok is the "." or "->" of a call and starts the next
42 // segment of a builder type call.
43 static bool startsSegmentOfBuilderTypeCall(const FormatToken &Tok) {
44   return Tok.isMemberAccess() && Tok.Previous && Tok.Previous->closesScope();
45 }
46 
47 // Returns \c true if \c Current starts a new parameter.
48 static bool startsNextParameter(const FormatToken &Current,
49                                 const FormatStyle &Style) {
50   const FormatToken &Previous = *Current.Previous;
51   if (Current.Type == TT_CtorInitializerComma &&
52       Style.BreakConstructorInitializersBeforeComma)
53     return true;
54   return Previous.is(tok::comma) && !Current.isTrailingComment() &&
55          (Previous.Type != TT_CtorInitializerComma ||
56           !Style.BreakConstructorInitializersBeforeComma);
57 }
58 
59 ContinuationIndenter::ContinuationIndenter(const FormatStyle &Style,
60                                            SourceManager &SourceMgr,
61                                            WhitespaceManager &Whitespaces,
62                                            encoding::Encoding Encoding,
63                                            bool BinPackInconclusiveFunctions)
64     : Style(Style), SourceMgr(SourceMgr), Whitespaces(Whitespaces),
65       Encoding(Encoding),
66       BinPackInconclusiveFunctions(BinPackInconclusiveFunctions),
67       CommentPragmasRegex(Style.CommentPragmas) {}
68 
69 LineState ContinuationIndenter::getInitialState(unsigned FirstIndent,
70                                                 const AnnotatedLine *Line,
71                                                 bool DryRun) {
72   LineState State;
73   State.FirstIndent = FirstIndent;
74   State.Column = FirstIndent;
75   State.Line = Line;
76   State.NextToken = Line->First;
77   State.Stack.push_back(ParenState(FirstIndent, Line->Level, FirstIndent,
78                                    /*AvoidBinPacking=*/false,
79                                    /*NoLineBreak=*/false));
80   State.LineContainsContinuedForLoopSection = false;
81   State.StartOfStringLiteral = 0;
82   State.StartOfLineLevel = 0;
83   State.LowestLevelOnLine = 0;
84   State.IgnoreStackForComparison = false;
85 
86   // The first token has already been indented and thus consumed.
87   moveStateToNextToken(State, DryRun, /*Newline=*/false);
88   return State;
89 }
90 
91 bool ContinuationIndenter::canBreak(const LineState &State) {
92   const FormatToken &Current = *State.NextToken;
93   const FormatToken &Previous = *Current.Previous;
94   assert(&Previous == Current.Previous);
95   if (!Current.CanBreakBefore && !(State.Stack.back().BreakBeforeClosingBrace &&
96                                    Current.closesBlockTypeList(Style)))
97     return false;
98   // The opening "{" of a braced list has to be on the same line as the first
99   // element if it is nested in another braced init list or function call.
100   if (!Current.MustBreakBefore && Previous.is(tok::l_brace) &&
101       Previous.Type != TT_DictLiteral && Previous.BlockKind == BK_BracedInit &&
102       Previous.Previous &&
103       Previous.Previous->isOneOf(tok::l_brace, tok::l_paren, tok::comma))
104     return false;
105   // This prevents breaks like:
106   //   ...
107   //   SomeParameter, OtherParameter).DoSomething(
108   //   ...
109   // As they hide "DoSomething" and are generally bad for readability.
110   if (Previous.opensScope() && Previous.isNot(tok::l_brace) &&
111       State.LowestLevelOnLine < State.StartOfLineLevel &&
112       State.LowestLevelOnLine < Current.NestingLevel)
113     return false;
114   if (Current.isMemberAccess() && State.Stack.back().ContainsUnwrappedBuilder)
115     return false;
116 
117   // Don't create a 'hanging' indent if there are multiple blocks in a single
118   // statement.
119   if (Style.Language == FormatStyle::LK_JavaScript &&
120       Previous.is(tok::l_brace) && State.Stack.size() > 1 &&
121       State.Stack[State.Stack.size() - 2].JSFunctionInlined &&
122       State.Stack[State.Stack.size() - 2].HasMultipleNestedBlocks)
123     return false;
124 
125   return !State.Stack.back().NoLineBreak;
126 }
127 
128 bool ContinuationIndenter::mustBreak(const LineState &State) {
129   const FormatToken &Current = *State.NextToken;
130   const FormatToken &Previous = *Current.Previous;
131   if (Current.MustBreakBefore || Current.Type == TT_InlineASMColon)
132     return true;
133   if (State.Stack.back().BreakBeforeClosingBrace &&
134       Current.closesBlockTypeList(Style))
135     return true;
136   if (Previous.is(tok::semi) && State.LineContainsContinuedForLoopSection)
137     return true;
138   if ((startsNextParameter(Current, Style) || Previous.is(tok::semi) ||
139        (Style.BreakBeforeTernaryOperators &&
140         (Current.is(tok::question) || (Current.Type == TT_ConditionalExpr &&
141                                        Previous.isNot(tok::question)))) ||
142        (!Style.BreakBeforeTernaryOperators &&
143         (Previous.is(tok::question) || Previous.Type == TT_ConditionalExpr))) &&
144       State.Stack.back().BreakBeforeParameter && !Current.isTrailingComment() &&
145       !Current.isOneOf(tok::r_paren, tok::r_brace))
146     return true;
147   if (Style.AlwaysBreakBeforeMultilineStrings &&
148       State.Column > State.Stack.back().Indent && // Breaking saves columns.
149       !Previous.isOneOf(tok::kw_return, tok::lessless, tok::at) &&
150       Previous.Type != TT_InlineASMColon &&
151       Previous.Type != TT_ConditionalExpr && nextIsMultilineString(State))
152     return true;
153   if (Style.Language != FormatStyle::LK_Proto &&
154       ((Previous.Type == TT_DictLiteral && Previous.is(tok::l_brace)) ||
155        Previous.Type == TT_ArrayInitializerLSquare) &&
156       Style.ColumnLimit > 0 &&
157       getLengthToMatchingParen(Previous) + State.Column > getColumnLimit(State))
158     return true;
159   if (Current.Type == TT_CtorInitializerColon &&
160       ((Style.AllowShortFunctionsOnASingleLine != FormatStyle::SFS_All) ||
161        Style.BreakConstructorInitializersBeforeComma || Style.ColumnLimit != 0))
162     return true;
163 
164   if (State.Column < getNewLineColumn(State))
165     return false;
166   if (!Style.BreakBeforeBinaryOperators) {
167     // If we need to break somewhere inside the LHS of a binary expression, we
168     // should also break after the operator. Otherwise, the formatting would
169     // hide the operator precedence, e.g. in:
170     //   if (aaaaaaaaaaaaaa ==
171     //           bbbbbbbbbbbbbb && c) {..
172     // For comparisons, we only apply this rule, if the LHS is a binary
173     // expression itself as otherwise, the line breaks seem superfluous.
174     // We need special cases for ">>" which we have split into two ">" while
175     // lexing in order to make template parsing easier.
176     //
177     // FIXME: We'll need something similar for styles that break before binary
178     // operators.
179     bool IsComparison = (Previous.getPrecedence() == prec::Relational ||
180                          Previous.getPrecedence() == prec::Equality) &&
181                         Previous.Previous &&
182                         Previous.Previous->Type != TT_BinaryOperator; // For >>.
183     bool LHSIsBinaryExpr =
184         Previous.Previous && Previous.Previous->EndsBinaryExpression;
185     if (Previous.Type == TT_BinaryOperator &&
186         (!IsComparison || LHSIsBinaryExpr) &&
187         Current.Type != TT_BinaryOperator && // For >>.
188         !Current.isTrailingComment() && !Previous.is(tok::lessless) &&
189         Previous.getPrecedence() != prec::Assignment &&
190         State.Stack.back().BreakBeforeParameter)
191       return true;
192   }
193 
194   // Same as above, but for the first "<<" operator.
195   if (Current.is(tok::lessless) && Current.Type != TT_OverloadedOperator &&
196       State.Stack.back().BreakBeforeParameter &&
197       State.Stack.back().FirstLessLess == 0)
198     return true;
199 
200   if (Current.Type == TT_SelectorName &&
201       State.Stack.back().ObjCSelectorNameFound &&
202       State.Stack.back().BreakBeforeParameter)
203     return true;
204   if (Previous.ClosesTemplateDeclaration && Current.NestingLevel == 0 &&
205       !Current.isTrailingComment())
206     return true;
207 
208   // If the return type spans multiple lines, wrap before the function name.
209   if ((Current.Type == TT_FunctionDeclarationName ||
210        Current.is(tok::kw_operator)) &&
211       State.Stack.back().BreakBeforeParameter)
212     return true;
213 
214   if (startsSegmentOfBuilderTypeCall(Current) &&
215       (State.Stack.back().CallContinuation != 0 ||
216        (State.Stack.back().BreakBeforeParameter &&
217         State.Stack.back().ContainsUnwrappedBuilder)))
218     return true;
219 
220   // The following could be precomputed as they do not depend on the state.
221   // However, as they should take effect only if the UnwrappedLine does not fit
222   // into the ColumnLimit, they are checked here in the ContinuationIndenter.
223   if (Style.ColumnLimit != 0 && Previous.BlockKind == BK_Block &&
224       Previous.is(tok::l_brace) && !Current.isOneOf(tok::r_brace, tok::comment))
225     return true;
226 
227   return false;
228 }
229 
230 unsigned ContinuationIndenter::addTokenToState(LineState &State, bool Newline,
231                                                bool DryRun,
232                                                unsigned ExtraSpaces) {
233   const FormatToken &Current = *State.NextToken;
234 
235   assert(!State.Stack.empty());
236   if ((Current.Type == TT_ImplicitStringLiteral &&
237        (Current.Previous->Tok.getIdentifierInfo() == nullptr ||
238         Current.Previous->Tok.getIdentifierInfo()->getPPKeywordID() ==
239             tok::pp_not_keyword))) {
240     // FIXME: Is this correct?
241     int WhitespaceLength = SourceMgr.getSpellingColumnNumber(
242                                State.NextToken->WhitespaceRange.getEnd()) -
243                            SourceMgr.getSpellingColumnNumber(
244                                State.NextToken->WhitespaceRange.getBegin());
245     State.Column += WhitespaceLength;
246     moveStateToNextToken(State, DryRun, /*Newline=*/false);
247     return 0;
248   }
249 
250   unsigned Penalty = 0;
251   if (Newline)
252     Penalty = addTokenOnNewLine(State, DryRun);
253   else
254     addTokenOnCurrentLine(State, DryRun, ExtraSpaces);
255 
256   return moveStateToNextToken(State, DryRun, Newline) + Penalty;
257 }
258 
259 void ContinuationIndenter::addTokenOnCurrentLine(LineState &State, bool DryRun,
260                                                  unsigned ExtraSpaces) {
261   FormatToken &Current = *State.NextToken;
262   const FormatToken &Previous = *State.NextToken->Previous;
263   if (Current.is(tok::equal) &&
264       (State.Line->First->is(tok::kw_for) || Current.NestingLevel == 0) &&
265       State.Stack.back().VariablePos == 0) {
266     State.Stack.back().VariablePos = State.Column;
267     // Move over * and & if they are bound to the variable name.
268     const FormatToken *Tok = &Previous;
269     while (Tok && State.Stack.back().VariablePos >= Tok->ColumnWidth) {
270       State.Stack.back().VariablePos -= Tok->ColumnWidth;
271       if (Tok->SpacesRequiredBefore != 0)
272         break;
273       Tok = Tok->Previous;
274     }
275     if (Previous.PartOfMultiVariableDeclStmt)
276       State.Stack.back().LastSpace = State.Stack.back().VariablePos;
277   }
278 
279   unsigned Spaces = Current.SpacesRequiredBefore + ExtraSpaces;
280 
281   if (!DryRun)
282     Whitespaces.replaceWhitespace(Current, /*Newlines=*/0, /*IndentLevel=*/0,
283                                   Spaces, State.Column + Spaces);
284 
285   if (Current.Type == TT_SelectorName &&
286       !State.Stack.back().ObjCSelectorNameFound) {
287     if (Current.LongestObjCSelectorName == 0)
288       State.Stack.back().AlignColons = false;
289     else if (State.Stack.back().Indent + Current.LongestObjCSelectorName >
290              State.Column + Spaces + Current.ColumnWidth)
291       State.Stack.back().ColonPos =
292           State.Stack.back().Indent + Current.LongestObjCSelectorName;
293     else
294       State.Stack.back().ColonPos = State.Column + Spaces + Current.ColumnWidth;
295   }
296 
297   if (Previous.opensScope() && Previous.Type != TT_ObjCMethodExpr &&
298       (Current.Type != TT_LineComment || Previous.BlockKind == BK_BracedInit))
299     State.Stack.back().Indent = State.Column + Spaces;
300   if (State.Stack.back().AvoidBinPacking && startsNextParameter(Current, Style))
301     State.Stack.back().NoLineBreak = true;
302   if (startsSegmentOfBuilderTypeCall(Current))
303     State.Stack.back().ContainsUnwrappedBuilder = true;
304 
305   if (Current.isMemberAccess() && Previous.is(tok::r_paren) &&
306       (Previous.MatchingParen &&
307        (Previous.TotalLength - Previous.MatchingParen->TotalLength > 10))) {
308     // If there is a function call with long parameters, break before trailing
309     // calls. This prevents things like:
310     //   EXPECT_CALL(SomeLongParameter).Times(
311     //       2);
312     // We don't want to do this for short parameters as they can just be
313     // indexes.
314     State.Stack.back().NoLineBreak = true;
315   }
316 
317   State.Column += Spaces;
318   if (Current.isNot(tok::comment) && Previous.is(tok::l_paren) &&
319       Previous.Previous && Previous.Previous->isOneOf(tok::kw_if, tok::kw_for))
320     // Treat the condition inside an if as if it was a second function
321     // parameter, i.e. let nested calls have a continuation indent.
322     State.Stack.back().LastSpace = State.Column;
323   else if (!Current.isOneOf(tok::comment, tok::caret) &&
324            (Previous.is(tok::comma) ||
325             (Previous.is(tok::colon) && Previous.Type == TT_ObjCMethodExpr)))
326     State.Stack.back().LastSpace = State.Column;
327   else if ((Previous.Type == TT_BinaryOperator ||
328             Previous.Type == TT_ConditionalExpr ||
329             Previous.Type == TT_CtorInitializerColon) &&
330            ((Previous.getPrecedence() != prec::Assignment &&
331              (Previous.isNot(tok::lessless) || Previous.OperatorIndex != 0 ||
332               !Previous.LastOperator)) ||
333             Current.StartsBinaryExpression))
334     // Always indent relative to the RHS of the expression unless this is a
335     // simple assignment without binary expression on the RHS. Also indent
336     // relative to unary operators and the colons of constructor initializers.
337     State.Stack.back().LastSpace = State.Column;
338   else if (Previous.Type == TT_InheritanceColon) {
339     State.Stack.back().Indent = State.Column;
340     State.Stack.back().LastSpace = State.Column;
341   } else if (Previous.opensScope()) {
342     // If a function has a trailing call, indent all parameters from the
343     // opening parenthesis. This avoids confusing indents like:
344     //   OuterFunction(InnerFunctionCall( // break
345     //       ParameterToInnerFunction))   // break
346     //       .SecondInnerFunctionCall();
347     bool HasTrailingCall = false;
348     if (Previous.MatchingParen) {
349       const FormatToken *Next = Previous.MatchingParen->getNextNonComment();
350       HasTrailingCall = Next && Next->isMemberAccess();
351     }
352     if (HasTrailingCall &&
353         State.Stack[State.Stack.size() - 2].CallContinuation == 0)
354       State.Stack.back().LastSpace = State.Column;
355   }
356 }
357 
358 unsigned ContinuationIndenter::addTokenOnNewLine(LineState &State,
359                                                  bool DryRun) {
360   FormatToken &Current = *State.NextToken;
361   const FormatToken &Previous = *State.NextToken->Previous;
362 
363   // Extra penalty that needs to be added because of the way certain line
364   // breaks are chosen.
365   unsigned Penalty = 0;
366 
367   const FormatToken *PreviousNonComment = Current.getPreviousNonComment();
368   const FormatToken *NextNonComment = Previous.getNextNonComment();
369   if (!NextNonComment)
370     NextNonComment = &Current;
371   // The first line break on any NestingLevel causes an extra penalty in order
372   // prefer similar line breaks.
373   if (!State.Stack.back().ContainsLineBreak)
374     Penalty += 15;
375   State.Stack.back().ContainsLineBreak = true;
376 
377   Penalty += State.NextToken->SplitPenalty;
378 
379   // Breaking before the first "<<" is generally not desirable if the LHS is
380   // short. Also always add the penalty if the LHS is split over mutliple lines
381   // to avoid unnecessary line breaks that just work around this penalty.
382   if (NextNonComment->is(tok::lessless) &&
383       State.Stack.back().FirstLessLess == 0 &&
384       (State.Column <= Style.ColumnLimit / 3 ||
385        State.Stack.back().BreakBeforeParameter))
386     Penalty += Style.PenaltyBreakFirstLessLess;
387 
388   State.Column = getNewLineColumn(State);
389   if (NextNonComment->isMemberAccess()) {
390     if (State.Stack.back().CallContinuation == 0)
391       State.Stack.back().CallContinuation = State.Column;
392   } else if (NextNonComment->Type == TT_SelectorName) {
393     if (!State.Stack.back().ObjCSelectorNameFound) {
394       if (NextNonComment->LongestObjCSelectorName == 0) {
395         State.Stack.back().AlignColons = false;
396       } else {
397         State.Stack.back().ColonPos =
398             State.Stack.back().Indent + NextNonComment->LongestObjCSelectorName;
399       }
400     } else if (State.Stack.back().AlignColons &&
401                State.Stack.back().ColonPos <= NextNonComment->ColumnWidth) {
402       State.Stack.back().ColonPos = State.Column + NextNonComment->ColumnWidth;
403     }
404   } else if (PreviousNonComment && PreviousNonComment->is(tok::colon) &&
405              (PreviousNonComment->Type == TT_ObjCMethodExpr ||
406               PreviousNonComment->Type == TT_DictLiteral)) {
407     // FIXME: This is hacky, find a better way. The problem is that in an ObjC
408     // method expression, the block should be aligned to the line starting it,
409     // e.g.:
410     //   [aaaaaaaaaaaaaaa aaaaaaaaa: \\ break for some reason
411     //                        ^(int *i) {
412     //                            // ...
413     //                        }];
414     // Thus, we set LastSpace of the next higher NestingLevel, to which we move
415     // when we consume all of the "}"'s FakeRParens at the "{".
416     if (State.Stack.size() > 1)
417       State.Stack[State.Stack.size() - 2].LastSpace =
418           std::max(State.Stack.back().LastSpace, State.Stack.back().Indent) +
419           Style.ContinuationIndentWidth;
420   }
421 
422   if ((Previous.isOneOf(tok::comma, tok::semi) &&
423        !State.Stack.back().AvoidBinPacking) ||
424       Previous.Type == TT_BinaryOperator)
425     State.Stack.back().BreakBeforeParameter = false;
426   if (Previous.Type == TT_TemplateCloser && Current.NestingLevel == 0)
427     State.Stack.back().BreakBeforeParameter = false;
428   if (NextNonComment->is(tok::question) ||
429       (PreviousNonComment && PreviousNonComment->is(tok::question)))
430     State.Stack.back().BreakBeforeParameter = true;
431 
432   if (!DryRun) {
433     unsigned Newlines = std::max(
434         1u, std::min(Current.NewlinesBefore, Style.MaxEmptyLinesToKeep + 1));
435     Whitespaces.replaceWhitespace(Current, Newlines,
436                                   State.Stack.back().IndentLevel, State.Column,
437                                   State.Column, State.Line->InPPDirective);
438   }
439 
440   if (!Current.isTrailingComment())
441     State.Stack.back().LastSpace = State.Column;
442   State.StartOfLineLevel = Current.NestingLevel;
443   State.LowestLevelOnLine = Current.NestingLevel;
444 
445   // Any break on this level means that the parent level has been broken
446   // and we need to avoid bin packing there.
447   bool JavaScriptFormat = Style.Language == FormatStyle::LK_JavaScript &&
448                           Current.is(tok::r_brace) &&
449                           State.Stack.size() > 1 &&
450                           State.Stack[State.Stack.size() - 2].JSFunctionInlined;
451   if (!JavaScriptFormat) {
452     for (unsigned i = 0, e = State.Stack.size() - 1; i != e; ++i) {
453       State.Stack[i].BreakBeforeParameter = true;
454     }
455   }
456 
457   if (PreviousNonComment &&
458       !PreviousNonComment->isOneOf(tok::comma, tok::semi) &&
459       PreviousNonComment->Type != TT_TemplateCloser &&
460       PreviousNonComment->Type != TT_BinaryOperator &&
461       Current.Type != TT_BinaryOperator && !PreviousNonComment->opensScope())
462     State.Stack.back().BreakBeforeParameter = true;
463 
464   // If we break after { or the [ of an array initializer, we should also break
465   // before the corresponding } or ].
466   if (PreviousNonComment &&
467       (PreviousNonComment->is(tok::l_brace) ||
468        PreviousNonComment->Type == TT_ArrayInitializerLSquare))
469     State.Stack.back().BreakBeforeClosingBrace = true;
470 
471   if (State.Stack.back().AvoidBinPacking) {
472     // If we are breaking after '(', '{', '<', this is not bin packing
473     // unless AllowAllParametersOfDeclarationOnNextLine is false or this is a
474     // dict/object literal.
475     if (!(Previous.isOneOf(tok::l_paren, tok::l_brace) ||
476           Previous.Type == TT_BinaryOperator) ||
477         (!Style.AllowAllParametersOfDeclarationOnNextLine &&
478          State.Line->MustBeDeclaration) ||
479         Previous.Type == TT_DictLiteral)
480       State.Stack.back().BreakBeforeParameter = true;
481   }
482 
483   return Penalty;
484 }
485 
486 unsigned ContinuationIndenter::getNewLineColumn(const LineState &State) {
487   if (!State.NextToken || !State.NextToken->Previous)
488     return 0;
489   FormatToken &Current = *State.NextToken;
490   const FormatToken &Previous = *Current.Previous;
491   // If we are continuing an expression, we want to use the continuation indent.
492   unsigned ContinuationIndent =
493       std::max(State.Stack.back().LastSpace, State.Stack.back().Indent) +
494       Style.ContinuationIndentWidth;
495   const FormatToken *PreviousNonComment = Current.getPreviousNonComment();
496   const FormatToken *NextNonComment = Previous.getNextNonComment();
497   if (!NextNonComment)
498     NextNonComment = &Current;
499   if (NextNonComment->is(tok::l_brace) && NextNonComment->BlockKind == BK_Block)
500     return Current.NestingLevel == 0 ? State.FirstIndent
501                                      : State.Stack.back().Indent;
502   if (Current.isOneOf(tok::r_brace, tok::r_square)) {
503     if (State.Stack.size() > 1 &&
504         State.Stack[State.Stack.size() - 2].JSFunctionInlined)
505       return State.FirstIndent;
506     if (Current.closesBlockTypeList(Style) ||
507         (Current.MatchingParen &&
508          Current.MatchingParen->BlockKind == BK_BracedInit))
509       return State.Stack[State.Stack.size() - 2].LastSpace;
510     else
511       return State.FirstIndent;
512   }
513   if (Current.is(tok::identifier) && Current.Next &&
514       Current.Next->Type == TT_DictLiteral)
515     return State.Stack.back().Indent;
516   if (NextNonComment->isStringLiteral() && State.StartOfStringLiteral != 0)
517     return State.StartOfStringLiteral;
518   if (NextNonComment->is(tok::lessless) &&
519       State.Stack.back().FirstLessLess != 0)
520     return State.Stack.back().FirstLessLess;
521   if (NextNonComment->isMemberAccess()) {
522     if (State.Stack.back().CallContinuation == 0) {
523       return ContinuationIndent;
524     } else {
525       return State.Stack.back().CallContinuation;
526     }
527   }
528   if (State.Stack.back().QuestionColumn != 0 &&
529       ((NextNonComment->is(tok::colon) &&
530         NextNonComment->Type == TT_ConditionalExpr) ||
531        Previous.Type == TT_ConditionalExpr))
532     return State.Stack.back().QuestionColumn;
533   if (Previous.is(tok::comma) && State.Stack.back().VariablePos != 0)
534     return State.Stack.back().VariablePos;
535   if ((PreviousNonComment && (PreviousNonComment->ClosesTemplateDeclaration ||
536                               PreviousNonComment->Type == TT_AttributeParen)) ||
537       (!Style.IndentWrappedFunctionNames &&
538        (NextNonComment->is(tok::kw_operator) ||
539         NextNonComment->Type == TT_FunctionDeclarationName)))
540     return std::max(State.Stack.back().LastSpace, State.Stack.back().Indent);
541   if (NextNonComment->Type == TT_SelectorName) {
542     if (!State.Stack.back().ObjCSelectorNameFound) {
543       if (NextNonComment->LongestObjCSelectorName == 0) {
544         return State.Stack.back().Indent;
545       } else {
546         return State.Stack.back().Indent +
547                NextNonComment->LongestObjCSelectorName -
548                NextNonComment->ColumnWidth;
549       }
550     } else if (!State.Stack.back().AlignColons) {
551       return State.Stack.back().Indent;
552     } else if (State.Stack.back().ColonPos > NextNonComment->ColumnWidth) {
553       return State.Stack.back().ColonPos - NextNonComment->ColumnWidth;
554     } else {
555       return State.Stack.back().Indent;
556     }
557   }
558   if (NextNonComment->Type == TT_ArraySubscriptLSquare) {
559     if (State.Stack.back().StartOfArraySubscripts != 0)
560       return State.Stack.back().StartOfArraySubscripts;
561     else
562       return ContinuationIndent;
563   }
564   if (NextNonComment->Type == TT_StartOfName ||
565       Previous.isOneOf(tok::coloncolon, tok::equal)) {
566     return ContinuationIndent;
567   }
568   if (PreviousNonComment && PreviousNonComment->is(tok::colon) &&
569       (PreviousNonComment->Type == TT_ObjCMethodExpr ||
570        PreviousNonComment->Type == TT_DictLiteral))
571     return ContinuationIndent;
572   if (NextNonComment->Type == TT_CtorInitializerColon)
573     return State.FirstIndent + Style.ConstructorInitializerIndentWidth;
574   if (NextNonComment->Type == TT_CtorInitializerComma)
575     return State.Stack.back().Indent;
576   if (Previous.is(tok::r_paren) && !Current.isBinaryOperator() &&
577       Current.isNot(tok::colon))
578     return ContinuationIndent;
579   if (State.Stack.back().Indent == State.FirstIndent && PreviousNonComment &&
580       PreviousNonComment->isNot(tok::r_brace))
581     // Ensure that we fall back to the continuation indent width instead of
582     // just flushing continuations left.
583     return State.Stack.back().Indent + Style.ContinuationIndentWidth;
584   return State.Stack.back().Indent;
585 }
586 
587 unsigned ContinuationIndenter::moveStateToNextToken(LineState &State,
588                                                     bool DryRun, bool Newline) {
589   assert(State.Stack.size());
590   const FormatToken &Current = *State.NextToken;
591 
592   if (Current.Type == TT_InheritanceColon)
593     State.Stack.back().AvoidBinPacking = true;
594   if (Current.is(tok::lessless) && Current.Type != TT_OverloadedOperator) {
595     if (State.Stack.back().FirstLessLess == 0)
596       State.Stack.back().FirstLessLess = State.Column;
597     else
598       State.Stack.back().LastOperatorWrapped = Newline;
599   }
600   if ((Current.Type == TT_BinaryOperator && Current.isNot(tok::lessless)) ||
601       Current.Type == TT_ConditionalExpr)
602     State.Stack.back().LastOperatorWrapped = Newline;
603   if (Current.Type == TT_ArraySubscriptLSquare &&
604       State.Stack.back().StartOfArraySubscripts == 0)
605     State.Stack.back().StartOfArraySubscripts = State.Column;
606   if ((Current.is(tok::question) && Style.BreakBeforeTernaryOperators) ||
607       (Current.getPreviousNonComment() && Current.isNot(tok::colon) &&
608        Current.getPreviousNonComment()->is(tok::question) &&
609        !Style.BreakBeforeTernaryOperators))
610     State.Stack.back().QuestionColumn = State.Column;
611   if (!Current.opensScope() && !Current.closesScope())
612     State.LowestLevelOnLine =
613         std::min(State.LowestLevelOnLine, Current.NestingLevel);
614   if (Current.isMemberAccess())
615     State.Stack.back().StartOfFunctionCall =
616         Current.LastOperator ? 0 : State.Column + Current.ColumnWidth;
617   if (Current.Type == TT_SelectorName)
618     State.Stack.back().ObjCSelectorNameFound = true;
619   if (Current.Type == TT_CtorInitializerColon) {
620     // Indent 2 from the column, so:
621     // SomeClass::SomeClass()
622     //     : First(...), ...
623     //       Next(...)
624     //       ^ line up here.
625     State.Stack.back().Indent =
626         State.Column + (Style.BreakConstructorInitializersBeforeComma ? 0 : 2);
627     if (Style.ConstructorInitializerAllOnOneLineOrOnePerLine)
628       State.Stack.back().AvoidBinPacking = true;
629     State.Stack.back().BreakBeforeParameter = false;
630   }
631 
632   // In ObjC method declaration we align on the ":" of parameters, but we need
633   // to ensure that we indent parameters on subsequent lines by at least our
634   // continuation indent width.
635   if (Current.Type == TT_ObjCMethodSpecifier)
636     State.Stack.back().Indent += Style.ContinuationIndentWidth;
637 
638   // Insert scopes created by fake parenthesis.
639   const FormatToken *Previous = Current.getPreviousNonComment();
640 
641   // Add special behavior to support a format commonly used for JavaScript
642   // closures:
643   //   SomeFunction(function() {
644   //     foo();
645   //     bar();
646   //   }, a, b, c);
647   if (Style.Language == FormatStyle::LK_JavaScript) {
648     if (Current.isNot(tok::comment) && Previous && Previous->is(tok::l_brace) &&
649         State.Stack.size() > 1) {
650       if (State.Stack[State.Stack.size() - 2].JSFunctionInlined && Newline) {
651         for (unsigned i = 0, e = State.Stack.size() - 1; i != e; ++i) {
652           State.Stack[i].NoLineBreak = true;
653         }
654       }
655       State.Stack[State.Stack.size() - 2].JSFunctionInlined = false;
656     }
657     if (Current.TokenText == "function")
658       State.Stack.back().JSFunctionInlined =
659           !Newline && Previous && Previous->Type != TT_DictLiteral &&
660           // If the unnamed function is the only parameter to another function,
661           // we can likely inline it and come up with a good format.
662           (Previous->isNot(tok::l_paren) || Previous->ParameterCount > 1);
663   }
664 
665   moveStatePastFakeLParens(State, Newline);
666   moveStatePastScopeOpener(State, Newline);
667   moveStatePastScopeCloser(State);
668   moveStatePastFakeRParens(State);
669 
670   if (Current.isStringLiteral() && State.StartOfStringLiteral == 0) {
671     State.StartOfStringLiteral = State.Column;
672   } else if (!Current.isOneOf(tok::comment, tok::identifier, tok::hash) &&
673              !Current.isStringLiteral()) {
674     State.StartOfStringLiteral = 0;
675   }
676 
677   State.Column += Current.ColumnWidth;
678   State.NextToken = State.NextToken->Next;
679   unsigned Penalty = breakProtrudingToken(Current, State, DryRun);
680   if (State.Column > getColumnLimit(State)) {
681     unsigned ExcessCharacters = State.Column - getColumnLimit(State);
682     Penalty += Style.PenaltyExcessCharacter * ExcessCharacters;
683   }
684 
685   if (Current.Role)
686     Current.Role->formatFromToken(State, this, DryRun);
687   // If the previous has a special role, let it consume tokens as appropriate.
688   // It is necessary to start at the previous token for the only implemented
689   // role (comma separated list). That way, the decision whether or not to break
690   // after the "{" is already done and both options are tried and evaluated.
691   // FIXME: This is ugly, find a better way.
692   if (Previous && Previous->Role)
693     Penalty += Previous->Role->formatAfterToken(State, this, DryRun);
694 
695   return Penalty;
696 }
697 
698 void ContinuationIndenter::moveStatePastFakeLParens(LineState &State,
699                                                     bool Newline) {
700   const FormatToken &Current = *State.NextToken;
701   const FormatToken *Previous = Current.getPreviousNonComment();
702 
703   // Don't add extra indentation for the first fake parenthesis after
704   // 'return', assignments or opening <({[. The indentation for these cases
705   // is special cased.
706   bool SkipFirstExtraIndent =
707       (Previous && (Previous->opensScope() || Previous->is(tok::kw_return) ||
708                     Previous->getPrecedence() == prec::Assignment ||
709                     Previous->Type == TT_ObjCMethodExpr));
710   for (SmallVectorImpl<prec::Level>::const_reverse_iterator
711            I = Current.FakeLParens.rbegin(),
712            E = Current.FakeLParens.rend();
713        I != E; ++I) {
714     ParenState NewParenState = State.Stack.back();
715     NewParenState.ContainsLineBreak = false;
716 
717     // Indent from 'LastSpace' unless this the fake parentheses encapsulating a
718     // builder type call after 'return'. If such a call is line-wrapped, we
719     // commonly just want to indent from the start of the line.
720     if (!Current.isTrailingComment() &&
721         (!Previous || Previous->isNot(tok::kw_return) || *I > 0))
722       NewParenState.Indent =
723           std::max(std::max(State.Column, NewParenState.Indent),
724                    State.Stack.back().LastSpace);
725 
726     // Don't allow the RHS of an operator to be split over multiple lines unless
727     // there is a line-break right after the operator.
728     // Exclude relational operators, as there, it is always more desirable to
729     // have the LHS 'left' of the RHS.
730     if (Previous && Previous->getPrecedence() > prec::Assignment &&
731         (Previous->Type == TT_BinaryOperator ||
732          Previous->Type == TT_ConditionalExpr) &&
733         Previous->getPrecedence() != prec::Relational) {
734       bool BreakBeforeOperator = Previous->is(tok::lessless) ||
735                                  (Previous->Type == TT_BinaryOperator &&
736                                   Style.BreakBeforeBinaryOperators) ||
737                                  (Previous->Type == TT_ConditionalExpr &&
738                                   Style.BreakBeforeTernaryOperators);
739       if ((!Newline && !BreakBeforeOperator) ||
740           (!State.Stack.back().LastOperatorWrapped && BreakBeforeOperator))
741         NewParenState.NoLineBreak = true;
742     }
743 
744     // Do not indent relative to the fake parentheses inserted for "." or "->".
745     // This is a special case to make the following to statements consistent:
746     //   OuterFunction(InnerFunctionCall( // break
747     //       ParameterToInnerFunction));
748     //   OuterFunction(SomeObject.InnerFunctionCall( // break
749     //       ParameterToInnerFunction));
750     if (*I > prec::Unknown)
751       NewParenState.LastSpace = std::max(NewParenState.LastSpace, State.Column);
752     NewParenState.StartOfFunctionCall = State.Column;
753 
754     // Always indent conditional expressions. Never indent expression where
755     // the 'operator' is ',', ';' or an assignment (i.e. *I <=
756     // prec::Assignment) as those have different indentation rules. Indent
757     // other expression, unless the indentation needs to be skipped.
758     if (*I == prec::Conditional ||
759         (!SkipFirstExtraIndent && *I > prec::Assignment &&
760          !Current.isTrailingComment() && !Style.BreakBeforeBinaryOperators))
761       NewParenState.Indent += Style.ContinuationIndentWidth;
762     if ((Previous && !Previous->opensScope()) || *I > prec::Comma)
763       NewParenState.BreakBeforeParameter = false;
764     State.Stack.push_back(NewParenState);
765     SkipFirstExtraIndent = false;
766   }
767 }
768 
769 // Remove the fake r_parens after 'Tok'.
770 static void consumeRParens(LineState& State, const FormatToken &Tok) {
771   for (unsigned i = 0, e = Tok.FakeRParens; i != e; ++i) {
772     unsigned VariablePos = State.Stack.back().VariablePos;
773     assert(State.Stack.size() > 1);
774     if (State.Stack.size() == 1) {
775       // Do not pop the last element.
776       break;
777     }
778     State.Stack.pop_back();
779     State.Stack.back().VariablePos = VariablePos;
780   }
781 }
782 
783 // Returns whether 'Tok' opens or closes a scope requiring special handling
784 // of the subsequent fake r_parens.
785 //
786 // For example, if this is an l_brace starting a nested block, we pretend (wrt.
787 // to indentation) that we already consumed the corresponding r_brace. Thus, we
788 // remove all ParenStates caused by fake parentheses that end at the r_brace.
789 // The net effect of this is that we don't indent relative to the l_brace, if
790 // the nested block is the last parameter of a function. This formats:
791 //
792 //   SomeFunction(a, [] {
793 //     f();  // break
794 //   });
795 //
796 // instead of:
797 //   SomeFunction(a, [] {
798 //                     f();  // break
799 //                   });
800 static bool fakeRParenSpecialCase(const LineState &State) {
801   const FormatToken &Tok = *State.NextToken;
802   if (!Tok.MatchingParen)
803     return false;
804   const FormatToken *Left = &Tok;
805   if (Tok.isOneOf(tok::r_brace, tok::r_square))
806     Left = Tok.MatchingParen;
807   return !State.Stack.back().HasMultipleNestedBlocks &&
808          Left->isOneOf(tok::l_brace, tok::l_square) &&
809          (Left->BlockKind == BK_Block ||
810           Left->Type == TT_ArrayInitializerLSquare ||
811           Left->Type == TT_DictLiteral);
812 }
813 
814 void ContinuationIndenter::moveStatePastFakeRParens(LineState &State) {
815   // Don't remove FakeRParens attached to r_braces that surround nested blocks
816   // as they will have been removed early (see above).
817   if (fakeRParenSpecialCase(State))
818     return;
819 
820   consumeRParens(State, *State.NextToken);
821 }
822 
823 void ContinuationIndenter::moveStatePastScopeOpener(LineState &State,
824                                                     bool Newline) {
825   const FormatToken &Current = *State.NextToken;
826   if (!Current.opensScope())
827     return;
828 
829   if (Current.MatchingParen && Current.BlockKind == BK_Block) {
830     moveStateToNewBlock(State);
831     return;
832   }
833 
834   unsigned NewIndent;
835   unsigned NewIndentLevel = State.Stack.back().IndentLevel;
836   bool AvoidBinPacking;
837   bool BreakBeforeParameter = false;
838   if (Current.is(tok::l_brace) || Current.Type == TT_ArrayInitializerLSquare) {
839     if (fakeRParenSpecialCase(State))
840       consumeRParens(State, *Current.MatchingParen);
841 
842     NewIndent = State.Stack.back().LastSpace;
843     if (Current.opensBlockTypeList(Style)) {
844       NewIndent += Style.IndentWidth;
845       NewIndent = std::min(State.Column + 2, NewIndent);
846       ++NewIndentLevel;
847     } else {
848       NewIndent += Style.ContinuationIndentWidth;
849       NewIndent = std::min(State.Column + 1, NewIndent);
850     }
851     const FormatToken *NextNoComment = Current.getNextNonComment();
852     AvoidBinPacking = Current.Type == TT_ArrayInitializerLSquare ||
853                       Current.Type == TT_DictLiteral ||
854                       Style.Language == FormatStyle::LK_Proto ||
855                       !Style.BinPackParameters ||
856                       (NextNoComment &&
857                        NextNoComment->Type == TT_DesignatedInitializerPeriod);
858   } else {
859     NewIndent = Style.ContinuationIndentWidth +
860                 std::max(State.Stack.back().LastSpace,
861                          State.Stack.back().StartOfFunctionCall);
862     AvoidBinPacking = !Style.BinPackParameters ||
863                       (Style.ExperimentalAutoDetectBinPacking &&
864                        (Current.PackingKind == PPK_OnePerLine ||
865                         (!BinPackInconclusiveFunctions &&
866                          Current.PackingKind == PPK_Inconclusive)));
867     // If this '[' opens an ObjC call, determine whether all parameters fit
868     // into one line and put one per line if they don't.
869     if (Current.Type == TT_ObjCMethodExpr && Style.ColumnLimit != 0 &&
870         getLengthToMatchingParen(Current) + State.Column >
871             getColumnLimit(State))
872       BreakBeforeParameter = true;
873   }
874   bool NoLineBreak = State.Stack.back().NoLineBreak ||
875                      (Current.Type == TT_TemplateOpener &&
876                       State.Stack.back().ContainsUnwrappedBuilder);
877   State.Stack.push_back(ParenState(NewIndent, NewIndentLevel,
878                                    State.Stack.back().LastSpace,
879                                    AvoidBinPacking, NoLineBreak));
880   State.Stack.back().BreakBeforeParameter = BreakBeforeParameter;
881   State.Stack.back().HasMultipleNestedBlocks = Current.BlockParameterCount > 1;
882 }
883 
884 void ContinuationIndenter::moveStatePastScopeCloser(LineState &State) {
885   const FormatToken &Current = *State.NextToken;
886   if (!Current.closesScope())
887     return;
888 
889   // If we encounter a closing ), ], } or >, we can remove a level from our
890   // stacks.
891   if (State.Stack.size() > 1 &&
892       (Current.isOneOf(tok::r_paren, tok::r_square) ||
893        (Current.is(tok::r_brace) && State.NextToken != State.Line->First) ||
894        State.NextToken->Type == TT_TemplateCloser))
895     State.Stack.pop_back();
896 
897   if (Current.is(tok::r_square)) {
898     // If this ends the array subscript expr, reset the corresponding value.
899     const FormatToken *NextNonComment = Current.getNextNonComment();
900     if (NextNonComment && NextNonComment->isNot(tok::l_square))
901       State.Stack.back().StartOfArraySubscripts = 0;
902   }
903 }
904 
905 void ContinuationIndenter::moveStateToNewBlock(LineState &State) {
906   // If we have already found more than one lambda introducers on this level, we
907   // opt out of this because similarity between the lambdas is more important.
908   if (fakeRParenSpecialCase(State))
909     consumeRParens(State, *State.NextToken->MatchingParen);
910 
911   // For some reason, ObjC blocks are indented like continuations.
912   unsigned NewIndent = State.Stack.back().LastSpace +
913                        (State.NextToken->Type == TT_ObjCBlockLBrace
914                             ? Style.ContinuationIndentWidth
915                             : Style.IndentWidth);
916   State.Stack.push_back(ParenState(
917       NewIndent, /*NewIndentLevel=*/State.Stack.back().IndentLevel + 1,
918       State.Stack.back().LastSpace, /*AvoidBinPacking=*/true,
919       State.Stack.back().NoLineBreak));
920   State.Stack.back().BreakBeforeParameter = true;
921 }
922 
923 unsigned ContinuationIndenter::addMultilineToken(const FormatToken &Current,
924                                                  LineState &State) {
925   // Break before further function parameters on all levels.
926   for (unsigned i = 0, e = State.Stack.size(); i != e; ++i)
927     State.Stack[i].BreakBeforeParameter = true;
928 
929   unsigned ColumnsUsed = State.Column;
930   // We can only affect layout of the first and the last line, so the penalty
931   // for all other lines is constant, and we ignore it.
932   State.Column = Current.LastLineColumnWidth;
933 
934   if (ColumnsUsed > getColumnLimit(State))
935     return Style.PenaltyExcessCharacter * (ColumnsUsed - getColumnLimit(State));
936   return 0;
937 }
938 
939 static bool getRawStringLiteralPrefixPostfix(StringRef Text, StringRef &Prefix,
940                                              StringRef &Postfix) {
941   if (Text.startswith(Prefix = "R\"") || Text.startswith(Prefix = "uR\"") ||
942       Text.startswith(Prefix = "UR\"") || Text.startswith(Prefix = "u8R\"") ||
943       Text.startswith(Prefix = "LR\"")) {
944     size_t ParenPos = Text.find('(');
945     if (ParenPos != StringRef::npos) {
946       StringRef Delimiter =
947           Text.substr(Prefix.size(), ParenPos - Prefix.size());
948       Prefix = Text.substr(0, ParenPos + 1);
949       Postfix = Text.substr(Text.size() - 2 - Delimiter.size());
950       return Postfix.front() == ')' && Postfix.back() == '"' &&
951              Postfix.substr(1).startswith(Delimiter);
952     }
953   }
954   return false;
955 }
956 
957 unsigned ContinuationIndenter::breakProtrudingToken(const FormatToken &Current,
958                                                     LineState &State,
959                                                     bool DryRun) {
960   // Don't break multi-line tokens other than block comments. Instead, just
961   // update the state.
962   if (Current.Type != TT_BlockComment && Current.IsMultiline)
963     return addMultilineToken(Current, State);
964 
965   // Don't break implicit string literals.
966   if (Current.Type == TT_ImplicitStringLiteral)
967     return 0;
968 
969   if (!Current.isStringLiteral() && !Current.is(tok::comment))
970     return 0;
971 
972   std::unique_ptr<BreakableToken> Token;
973   unsigned StartColumn = State.Column - Current.ColumnWidth;
974   unsigned ColumnLimit = getColumnLimit(State);
975 
976   if (Current.isStringLiteral()) {
977     // Don't break string literals inside preprocessor directives (except for
978     // #define directives, as their contents are stored in separate lines and
979     // are not affected by this check).
980     // This way we avoid breaking code with line directives and unknown
981     // preprocessor directives that contain long string literals.
982     if (State.Line->Type == LT_PreprocessorDirective)
983       return 0;
984     // Exempts unterminated string literals from line breaking. The user will
985     // likely want to terminate the string before any line breaking is done.
986     if (Current.IsUnterminatedLiteral)
987       return 0;
988 
989     StringRef Text = Current.TokenText;
990     StringRef Prefix;
991     StringRef Postfix;
992     bool IsNSStringLiteral = false;
993     // FIXME: Handle whitespace between '_T', '(', '"..."', and ')'.
994     // FIXME: Store Prefix and Suffix (or PrefixLength and SuffixLength to
995     // reduce the overhead) for each FormatToken, which is a string, so that we
996     // don't run multiple checks here on the hot path.
997     if (Text.startswith("\"") && Current.Previous &&
998         Current.Previous->is(tok::at)) {
999       IsNSStringLiteral = true;
1000       Prefix = "@\"";
1001     }
1002     if ((Text.endswith(Postfix = "\"") &&
1003          (IsNSStringLiteral || Text.startswith(Prefix = "\"") ||
1004           Text.startswith(Prefix = "u\"") || Text.startswith(Prefix = "U\"") ||
1005           Text.startswith(Prefix = "u8\"") ||
1006           Text.startswith(Prefix = "L\""))) ||
1007         (Text.startswith(Prefix = "_T(\"") && Text.endswith(Postfix = "\")")) ||
1008         getRawStringLiteralPrefixPostfix(Text, Prefix, Postfix)) {
1009       Token.reset(new BreakableStringLiteral(
1010           Current, State.Line->Level, StartColumn, Prefix, Postfix,
1011           State.Line->InPPDirective, Encoding, Style));
1012     } else {
1013       return 0;
1014     }
1015   } else if (Current.Type == TT_BlockComment && Current.isTrailingComment()) {
1016     if (CommentPragmasRegex.match(Current.TokenText.substr(2)))
1017       return 0;
1018     Token.reset(new BreakableBlockComment(
1019         Current, State.Line->Level, StartColumn, Current.OriginalColumn,
1020         !Current.Previous, State.Line->InPPDirective, Encoding, Style));
1021   } else if (Current.Type == TT_LineComment &&
1022              (Current.Previous == nullptr ||
1023               Current.Previous->Type != TT_ImplicitStringLiteral)) {
1024     if (CommentPragmasRegex.match(Current.TokenText.substr(2)))
1025       return 0;
1026     Token.reset(new BreakableLineComment(Current, State.Line->Level,
1027                                          StartColumn, /*InPPDirective=*/false,
1028                                          Encoding, Style));
1029     // We don't insert backslashes when breaking line comments.
1030     ColumnLimit = Style.ColumnLimit;
1031   } else {
1032     return 0;
1033   }
1034   if (Current.UnbreakableTailLength >= ColumnLimit)
1035     return 0;
1036 
1037   unsigned RemainingSpace = ColumnLimit - Current.UnbreakableTailLength;
1038   bool BreakInserted = false;
1039   unsigned Penalty = 0;
1040   unsigned RemainingTokenColumns = 0;
1041   for (unsigned LineIndex = 0, EndIndex = Token->getLineCount();
1042        LineIndex != EndIndex; ++LineIndex) {
1043     if (!DryRun)
1044       Token->replaceWhitespaceBefore(LineIndex, Whitespaces);
1045     unsigned TailOffset = 0;
1046     RemainingTokenColumns =
1047         Token->getLineLengthAfterSplit(LineIndex, TailOffset, StringRef::npos);
1048     while (RemainingTokenColumns > RemainingSpace) {
1049       BreakableToken::Split Split =
1050           Token->getSplit(LineIndex, TailOffset, ColumnLimit);
1051       if (Split.first == StringRef::npos) {
1052         // The last line's penalty is handled in addNextStateToQueue().
1053         if (LineIndex < EndIndex - 1)
1054           Penalty += Style.PenaltyExcessCharacter *
1055                      (RemainingTokenColumns - RemainingSpace);
1056         break;
1057       }
1058       assert(Split.first != 0);
1059       unsigned NewRemainingTokenColumns = Token->getLineLengthAfterSplit(
1060           LineIndex, TailOffset + Split.first + Split.second, StringRef::npos);
1061 
1062       // We can remove extra whitespace instead of breaking the line.
1063       if (RemainingTokenColumns + 1 - Split.second <= RemainingSpace) {
1064         RemainingTokenColumns = 0;
1065         if (!DryRun)
1066           Token->replaceWhitespace(LineIndex, TailOffset, Split, Whitespaces);
1067         break;
1068       }
1069 
1070       // When breaking before a tab character, it may be moved by a few columns,
1071       // but will still be expanded to the next tab stop, so we don't save any
1072       // columns.
1073       if (NewRemainingTokenColumns == RemainingTokenColumns)
1074         break;
1075 
1076       assert(NewRemainingTokenColumns < RemainingTokenColumns);
1077       if (!DryRun)
1078         Token->insertBreak(LineIndex, TailOffset, Split, Whitespaces);
1079       Penalty += Current.SplitPenalty;
1080       unsigned ColumnsUsed =
1081           Token->getLineLengthAfterSplit(LineIndex, TailOffset, Split.first);
1082       if (ColumnsUsed > ColumnLimit) {
1083         Penalty += Style.PenaltyExcessCharacter * (ColumnsUsed - ColumnLimit);
1084       }
1085       TailOffset += Split.first + Split.second;
1086       RemainingTokenColumns = NewRemainingTokenColumns;
1087       BreakInserted = true;
1088     }
1089   }
1090 
1091   State.Column = RemainingTokenColumns;
1092 
1093   if (BreakInserted) {
1094     // If we break the token inside a parameter list, we need to break before
1095     // the next parameter on all levels, so that the next parameter is clearly
1096     // visible. Line comments already introduce a break.
1097     if (Current.Type != TT_LineComment) {
1098       for (unsigned i = 0, e = State.Stack.size(); i != e; ++i)
1099         State.Stack[i].BreakBeforeParameter = true;
1100     }
1101 
1102     Penalty += Current.isStringLiteral() ? Style.PenaltyBreakString
1103                                          : Style.PenaltyBreakComment;
1104 
1105     State.Stack.back().LastSpace = StartColumn;
1106   }
1107   return Penalty;
1108 }
1109 
1110 unsigned ContinuationIndenter::getColumnLimit(const LineState &State) const {
1111   // In preprocessor directives reserve two chars for trailing " \"
1112   return Style.ColumnLimit - (State.Line->InPPDirective ? 2 : 0);
1113 }
1114 
1115 bool ContinuationIndenter::nextIsMultilineString(const LineState &State) {
1116   const FormatToken &Current = *State.NextToken;
1117   if (!Current.isStringLiteral() || Current.Type == TT_ImplicitStringLiteral)
1118     return false;
1119   // We never consider raw string literals "multiline" for the purpose of
1120   // AlwaysBreakBeforeMultilineStrings implementation as they are special-cased
1121   // (see TokenAnnotator::mustBreakBefore().
1122   if (Current.TokenText.startswith("R\""))
1123     return false;
1124   if (Current.IsMultiline)
1125     return true;
1126   if (Current.getNextNonComment() &&
1127       Current.getNextNonComment()->isStringLiteral())
1128     return true; // Implicit concatenation.
1129   if (State.Column + Current.ColumnWidth + Current.UnbreakableTailLength >
1130       Style.ColumnLimit)
1131     return true; // String will be split.
1132   return false;
1133 }
1134 
1135 } // namespace format
1136 } // namespace clang
1137