contrib/llvm/tools/clang/lib/Format/ContinuationIndenter.cpp

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