1 //===--- FormatToken.h - Format C++ code ------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 ///
9 /// \file
10 /// This file contains the declaration of the FormatToken, a wrapper
11 /// around Token with additional information related to formatting.
12 ///
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_CLANG_LIB_FORMAT_FORMATTOKEN_H
16 #define LLVM_CLANG_LIB_FORMAT_FORMATTOKEN_H
17 
18 #include "clang/Basic/IdentifierTable.h"
19 #include "clang/Basic/OperatorPrecedence.h"
20 #include "clang/Format/Format.h"
21 #include "clang/Lex/Lexer.h"
22 #include <memory>
23 #include <unordered_set>
24 
25 namespace clang {
26 namespace format {
27 
28 #define LIST_TOKEN_TYPES                                                       \
29   TYPE(ArrayInitializerLSquare)                                                \
30   TYPE(ArraySubscriptLSquare)                                                  \
31   TYPE(AttributeColon)                                                         \
32   TYPE(AttributeMacro)                                                         \
33   TYPE(AttributeParen)                                                         \
34   TYPE(AttributeSquare)                                                        \
35   TYPE(BinaryOperator)                                                         \
36   TYPE(BitFieldColon)                                                          \
37   TYPE(BlockComment)                                                           \
38   TYPE(CastRParen)                                                             \
39   TYPE(ConditionalExpr)                                                        \
40   TYPE(ConflictAlternative)                                                    \
41   TYPE(ConflictEnd)                                                            \
42   TYPE(ConflictStart)                                                          \
43   TYPE(ConstraintJunctions)                                                    \
44   TYPE(CtorInitializerColon)                                                   \
45   TYPE(CtorInitializerComma)                                                   \
46   TYPE(DesignatedInitializerLSquare)                                           \
47   TYPE(DesignatedInitializerPeriod)                                            \
48   TYPE(DictLiteral)                                                            \
49   TYPE(FatArrow)                                                               \
50   TYPE(ForEachMacro)                                                           \
51   TYPE(FunctionAnnotationRParen)                                               \
52   TYPE(FunctionDeclarationName)                                                \
53   TYPE(FunctionLBrace)                                                         \
54   TYPE(FunctionTypeLParen)                                                     \
55   TYPE(IfMacro)                                                                \
56   TYPE(ImplicitStringLiteral)                                                  \
57   TYPE(InheritanceColon)                                                       \
58   TYPE(InheritanceComma)                                                       \
59   TYPE(InlineASMBrace)                                                         \
60   TYPE(InlineASMColon)                                                         \
61   TYPE(InlineASMSymbolicNameLSquare)                                           \
62   TYPE(JavaAnnotation)                                                         \
63   TYPE(JsComputedPropertyName)                                                 \
64   TYPE(JsExponentiation)                                                       \
65   TYPE(JsExponentiationEqual)                                                  \
66   TYPE(JsPipePipeEqual)                                                        \
67   TYPE(JsPrivateIdentifier)                                                    \
68   TYPE(JsTypeColon)                                                            \
69   TYPE(JsTypeOperator)                                                         \
70   TYPE(JsTypeOptionalQuestion)                                                 \
71   TYPE(JsAndAndEqual)                                                          \
72   TYPE(LambdaArrow)                                                            \
73   TYPE(LambdaLBrace)                                                           \
74   TYPE(LambdaLSquare)                                                          \
75   TYPE(LeadingJavaAnnotation)                                                  \
76   TYPE(LineComment)                                                            \
77   TYPE(MacroBlockBegin)                                                        \
78   TYPE(MacroBlockEnd)                                                          \
79   TYPE(ModulePartitionColon)                                                   \
80   TYPE(NamespaceMacro)                                                         \
81   TYPE(NonNullAssertion)                                                       \
82   TYPE(NullCoalescingEqual)                                                    \
83   TYPE(NullCoalescingOperator)                                                 \
84   TYPE(NullPropagatingOperator)                                                \
85   TYPE(ObjCBlockLBrace)                                                        \
86   TYPE(ObjCBlockLParen)                                                        \
87   TYPE(ObjCDecl)                                                               \
88   TYPE(ObjCForIn)                                                              \
89   TYPE(ObjCMethodExpr)                                                         \
90   TYPE(ObjCMethodSpecifier)                                                    \
91   TYPE(ObjCProperty)                                                           \
92   TYPE(ObjCStringLiteral)                                                      \
93   TYPE(OverloadedOperator)                                                     \
94   TYPE(OverloadedOperatorLParen)                                               \
95   TYPE(PointerOrReference)                                                     \
96   TYPE(PureVirtualSpecifier)                                                   \
97   TYPE(RangeBasedForLoopColon)                                                 \
98   TYPE(RegexLiteral)                                                           \
99   TYPE(SelectorName)                                                           \
100   TYPE(StartOfName)                                                            \
101   TYPE(StatementAttributeLikeMacro)                                            \
102   TYPE(StatementMacro)                                                         \
103   TYPE(StructuredBindingLSquare)                                               \
104   TYPE(TemplateCloser)                                                         \
105   TYPE(TemplateOpener)                                                         \
106   TYPE(TemplateString)                                                         \
107   TYPE(ProtoExtensionLSquare)                                                  \
108   TYPE(TrailingAnnotation)                                                     \
109   TYPE(TrailingReturnArrow)                                                    \
110   TYPE(TrailingUnaryOperator)                                                  \
111   TYPE(TypeDeclarationParen)                                                   \
112   TYPE(TypenameMacro)                                                          \
113   TYPE(UnaryOperator)                                                          \
114   TYPE(UntouchableMacroFunc)                                                   \
115   TYPE(CSharpStringLiteral)                                                    \
116   TYPE(CSharpNamedArgumentColon)                                               \
117   TYPE(CSharpNullable)                                                         \
118   TYPE(CSharpNullConditionalLSquare)                                           \
119   TYPE(CSharpGenericTypeConstraint)                                            \
120   TYPE(CSharpGenericTypeConstraintColon)                                       \
121   TYPE(CSharpGenericTypeConstraintComma)                                       \
122   TYPE(Unknown)
123 
124 /// Determines the semantic type of a syntactic token, e.g. whether "<" is a
125 /// template opener or binary operator.
126 enum TokenType : uint8_t {
127 #define TYPE(X) TT_##X,
128   LIST_TOKEN_TYPES
129 #undef TYPE
130       NUM_TOKEN_TYPES
131 };
132 
133 /// Determines the name of a token type.
134 const char *getTokenTypeName(TokenType Type);
135 
136 // Represents what type of block a set of braces open.
137 enum BraceBlockKind { BK_Unknown, BK_Block, BK_BracedInit };
138 
139 // The packing kind of a function's parameters.
140 enum ParameterPackingKind { PPK_BinPacked, PPK_OnePerLine, PPK_Inconclusive };
141 
142 enum FormatDecision { FD_Unformatted, FD_Continue, FD_Break };
143 
144 /// Roles a token can take in a configured macro expansion.
145 enum MacroRole {
146   /// The token was expanded from a macro argument when formatting the expanded
147   /// token sequence.
148   MR_ExpandedArg,
149   /// The token is part of a macro argument that was previously formatted as
150   /// expansion when formatting the unexpanded macro call.
151   MR_UnexpandedArg,
152   /// The token was expanded from a macro definition, and is not visible as part
153   /// of the macro call.
154   MR_Hidden,
155 };
156 
157 struct FormatToken;
158 
159 /// Contains information on the token's role in a macro expansion.
160 ///
161 /// Given the following definitions:
162 /// A(X) = [ X ]
163 /// B(X) = < X >
164 /// C(X) = X
165 ///
166 /// Consider the macro call:
167 /// A({B(C(C(x)))}) -> [{<x>}]
168 ///
169 /// In this case, the tokens of the unexpanded macro call will have the
170 /// following relevant entries in their macro context (note that formatting
171 /// the unexpanded macro call happens *after* formatting the expanded macro
172 /// call):
173 ///                   A( { B( C( C(x) ) ) } )
174 /// Role:             NN U NN NN NNUN N N U N  (N=None, U=UnexpandedArg)
175 ///
176 ///                   [  { <       x    > } ]
177 /// Role:             H  E H       E    H E H  (H=Hidden, E=ExpandedArg)
178 /// ExpandedFrom[0]:  A  A A       A    A A A
179 /// ExpandedFrom[1]:       B       B    B
180 /// ExpandedFrom[2]:               C
181 /// ExpandedFrom[3]:               C
182 /// StartOfExpansion: 1  0 1       2    0 0 0
183 /// EndOfExpansion:   0  0 0       2    1 0 1
184 struct MacroExpansion {
185   MacroExpansion(MacroRole Role) : Role(Role) {}
186 
187   /// The token's role in the macro expansion.
188   /// When formatting an expanded macro, all tokens that are part of macro
189   /// arguments will be MR_ExpandedArg, while all tokens that are not visible in
190   /// the macro call will be MR_Hidden.
191   /// When formatting an unexpanded macro call, all tokens that are part of
192   /// macro arguments will be MR_UnexpandedArg.
193   MacroRole Role;
194 
195   /// The stack of macro call identifier tokens this token was expanded from.
196   llvm::SmallVector<FormatToken *, 1> ExpandedFrom;
197 
198   /// The number of expansions of which this macro is the first entry.
199   unsigned StartOfExpansion = 0;
200 
201   /// The number of currently open expansions in \c ExpandedFrom this macro is
202   /// the last token in.
203   unsigned EndOfExpansion = 0;
204 };
205 
206 class TokenRole;
207 class AnnotatedLine;
208 
209 /// A wrapper around a \c Token storing information about the
210 /// whitespace characters preceding it.
211 struct FormatToken {
212   FormatToken()
213       : HasUnescapedNewline(false), IsMultiline(false), IsFirst(false),
214         MustBreakBefore(false), IsUnterminatedLiteral(false),
215         CanBreakBefore(false), ClosesTemplateDeclaration(false),
216         StartsBinaryExpression(false), EndsBinaryExpression(false),
217         PartOfMultiVariableDeclStmt(false), ContinuesLineCommentSection(false),
218         Finalized(false), BlockKind(BK_Unknown), Decision(FD_Unformatted),
219         PackingKind(PPK_Inconclusive), Type(TT_Unknown) {}
220 
221   /// The \c Token.
222   Token Tok;
223 
224   /// The raw text of the token.
225   ///
226   /// Contains the raw token text without leading whitespace and without leading
227   /// escaped newlines.
228   StringRef TokenText;
229 
230   /// A token can have a special role that can carry extra information
231   /// about the token's formatting.
232   /// FIXME: Make FormatToken for parsing and AnnotatedToken two different
233   /// classes and make this a unique_ptr in the AnnotatedToken class.
234   std::shared_ptr<TokenRole> Role;
235 
236   /// The range of the whitespace immediately preceding the \c Token.
237   SourceRange WhitespaceRange;
238 
239   /// Whether there is at least one unescaped newline before the \c
240   /// Token.
241   unsigned HasUnescapedNewline : 1;
242 
243   /// Whether the token text contains newlines (escaped or not).
244   unsigned IsMultiline : 1;
245 
246   /// Indicates that this is the first token of the file.
247   unsigned IsFirst : 1;
248 
249   /// Whether there must be a line break before this token.
250   ///
251   /// This happens for example when a preprocessor directive ended directly
252   /// before the token.
253   unsigned MustBreakBefore : 1;
254 
255   /// Set to \c true if this token is an unterminated literal.
256   unsigned IsUnterminatedLiteral : 1;
257 
258   /// \c true if it is allowed to break before this token.
259   unsigned CanBreakBefore : 1;
260 
261   /// \c true if this is the ">" of "template<..>".
262   unsigned ClosesTemplateDeclaration : 1;
263 
264   /// \c true if this token starts a binary expression, i.e. has at least
265   /// one fake l_paren with a precedence greater than prec::Unknown.
266   unsigned StartsBinaryExpression : 1;
267   /// \c true if this token ends a binary expression.
268   unsigned EndsBinaryExpression : 1;
269 
270   /// Is this token part of a \c DeclStmt defining multiple variables?
271   ///
272   /// Only set if \c Type == \c TT_StartOfName.
273   unsigned PartOfMultiVariableDeclStmt : 1;
274 
275   /// Does this line comment continue a line comment section?
276   ///
277   /// Only set to true if \c Type == \c TT_LineComment.
278   unsigned ContinuesLineCommentSection : 1;
279 
280   /// If \c true, this token has been fully formatted (indented and
281   /// potentially re-formatted inside), and we do not allow further formatting
282   /// changes.
283   unsigned Finalized : 1;
284 
285 private:
286   /// Contains the kind of block if this token is a brace.
287   unsigned BlockKind : 2;
288 
289 public:
290   BraceBlockKind getBlockKind() const {
291     return static_cast<BraceBlockKind>(BlockKind);
292   }
293   void setBlockKind(BraceBlockKind BBK) {
294     BlockKind = BBK;
295     assert(getBlockKind() == BBK && "BraceBlockKind overflow!");
296   }
297 
298 private:
299   /// Stores the formatting decision for the token once it was made.
300   unsigned Decision : 2;
301 
302 public:
303   FormatDecision getDecision() const {
304     return static_cast<FormatDecision>(Decision);
305   }
306   void setDecision(FormatDecision D) {
307     Decision = D;
308     assert(getDecision() == D && "FormatDecision overflow!");
309   }
310 
311 private:
312   /// If this is an opening parenthesis, how are the parameters packed?
313   unsigned PackingKind : 2;
314 
315 public:
316   ParameterPackingKind getPackingKind() const {
317     return static_cast<ParameterPackingKind>(PackingKind);
318   }
319   void setPackingKind(ParameterPackingKind K) {
320     PackingKind = K;
321     assert(getPackingKind() == K && "ParameterPackingKind overflow!");
322   }
323 
324 private:
325   TokenType Type;
326 
327 public:
328   /// Returns the token's type, e.g. whether "<" is a template opener or
329   /// binary operator.
330   TokenType getType() const { return Type; }
331   void setType(TokenType T) { Type = T; }
332 
333   /// The number of newlines immediately before the \c Token.
334   ///
335   /// This can be used to determine what the user wrote in the original code
336   /// and thereby e.g. leave an empty line between two function definitions.
337   unsigned NewlinesBefore = 0;
338 
339   /// The offset just past the last '\n' in this token's leading
340   /// whitespace (relative to \c WhiteSpaceStart). 0 if there is no '\n'.
341   unsigned LastNewlineOffset = 0;
342 
343   /// The width of the non-whitespace parts of the token (or its first
344   /// line for multi-line tokens) in columns.
345   /// We need this to correctly measure number of columns a token spans.
346   unsigned ColumnWidth = 0;
347 
348   /// Contains the width in columns of the last line of a multi-line
349   /// token.
350   unsigned LastLineColumnWidth = 0;
351 
352   /// The number of spaces that should be inserted before this token.
353   unsigned SpacesRequiredBefore = 0;
354 
355   /// Number of parameters, if this is "(", "[" or "<".
356   unsigned ParameterCount = 0;
357 
358   /// Number of parameters that are nested blocks,
359   /// if this is "(", "[" or "<".
360   unsigned BlockParameterCount = 0;
361 
362   /// If this is a bracket ("<", "(", "[" or "{"), contains the kind of
363   /// the surrounding bracket.
364   tok::TokenKind ParentBracket = tok::unknown;
365 
366   /// The total length of the unwrapped line up to and including this
367   /// token.
368   unsigned TotalLength = 0;
369 
370   /// The original 0-based column of this token, including expanded tabs.
371   /// The configured TabWidth is used as tab width.
372   unsigned OriginalColumn = 0;
373 
374   /// The length of following tokens until the next natural split point,
375   /// or the next token that can be broken.
376   unsigned UnbreakableTailLength = 0;
377 
378   // FIXME: Come up with a 'cleaner' concept.
379   /// The binding strength of a token. This is a combined value of
380   /// operator precedence, parenthesis nesting, etc.
381   unsigned BindingStrength = 0;
382 
383   /// The nesting level of this token, i.e. the number of surrounding (),
384   /// [], {} or <>.
385   unsigned NestingLevel = 0;
386 
387   /// The indent level of this token. Copied from the surrounding line.
388   unsigned IndentLevel = 0;
389 
390   /// Penalty for inserting a line break before this token.
391   unsigned SplitPenalty = 0;
392 
393   /// If this is the first ObjC selector name in an ObjC method
394   /// definition or call, this contains the length of the longest name.
395   ///
396   /// This being set to 0 means that the selectors should not be colon-aligned,
397   /// e.g. because several of them are block-type.
398   unsigned LongestObjCSelectorName = 0;
399 
400   /// If this is the first ObjC selector name in an ObjC method
401   /// definition or call, this contains the number of parts that the whole
402   /// selector consist of.
403   unsigned ObjCSelectorNameParts = 0;
404 
405   /// The 0-based index of the parameter/argument. For ObjC it is set
406   /// for the selector name token.
407   /// For now calculated only for ObjC.
408   unsigned ParameterIndex = 0;
409 
410   /// Stores the number of required fake parentheses and the
411   /// corresponding operator precedence.
412   ///
413   /// If multiple fake parentheses start at a token, this vector stores them in
414   /// reverse order, i.e. inner fake parenthesis first.
415   SmallVector<prec::Level, 4> FakeLParens;
416   /// Insert this many fake ) after this token for correct indentation.
417   unsigned FakeRParens = 0;
418 
419   /// If this is an operator (or "."/"->") in a sequence of operators
420   /// with the same precedence, contains the 0-based operator index.
421   unsigned OperatorIndex = 0;
422 
423   /// If this is an operator (or "."/"->") in a sequence of operators
424   /// with the same precedence, points to the next operator.
425   FormatToken *NextOperator = nullptr;
426 
427   /// If this is a bracket, this points to the matching one.
428   FormatToken *MatchingParen = nullptr;
429 
430   /// The previous token in the unwrapped line.
431   FormatToken *Previous = nullptr;
432 
433   /// The next token in the unwrapped line.
434   FormatToken *Next = nullptr;
435 
436   /// The first token in set of column elements.
437   bool StartsColumn = false;
438 
439   /// This notes the start of the line of an array initializer.
440   bool ArrayInitializerLineStart = false;
441 
442   /// This starts an array initializer.
443   bool IsArrayInitializer = false;
444 
445   /// If this token starts a block, this contains all the unwrapped lines
446   /// in it.
447   SmallVector<AnnotatedLine *, 1> Children;
448 
449   // Contains all attributes related to how this token takes part
450   // in a configured macro expansion.
451   llvm::Optional<MacroExpansion> MacroCtx;
452 
453   bool is(tok::TokenKind Kind) const { return Tok.is(Kind); }
454   bool is(TokenType TT) const { return getType() == TT; }
455   bool is(const IdentifierInfo *II) const {
456     return II && II == Tok.getIdentifierInfo();
457   }
458   bool is(tok::PPKeywordKind Kind) const {
459     return Tok.getIdentifierInfo() &&
460            Tok.getIdentifierInfo()->getPPKeywordID() == Kind;
461   }
462   bool is(BraceBlockKind BBK) const { return getBlockKind() == BBK; }
463   bool is(ParameterPackingKind PPK) const { return getPackingKind() == PPK; }
464 
465   template <typename A, typename B> bool isOneOf(A K1, B K2) const {
466     return is(K1) || is(K2);
467   }
468   template <typename A, typename B, typename... Ts>
469   bool isOneOf(A K1, B K2, Ts... Ks) const {
470     return is(K1) || isOneOf(K2, Ks...);
471   }
472   template <typename T> bool isNot(T Kind) const { return !is(Kind); }
473 
474   bool isIf(bool AllowConstexprMacro = true) const {
475     return is(tok::kw_if) || endsSequence(tok::kw_constexpr, tok::kw_if) ||
476            (endsSequence(tok::identifier, tok::kw_if) && AllowConstexprMacro);
477   }
478 
479   bool closesScopeAfterBlock() const {
480     if (getBlockKind() == BK_Block)
481       return true;
482     if (closesScope())
483       return Previous->closesScopeAfterBlock();
484     return false;
485   }
486 
487   /// \c true if this token starts a sequence with the given tokens in order,
488   /// following the ``Next`` pointers, ignoring comments.
489   template <typename A, typename... Ts>
490   bool startsSequence(A K1, Ts... Tokens) const {
491     return startsSequenceInternal(K1, Tokens...);
492   }
493 
494   /// \c true if this token ends a sequence with the given tokens in order,
495   /// following the ``Previous`` pointers, ignoring comments.
496   /// For example, given tokens [T1, T2, T3], the function returns true if
497   /// 3 tokens ending at this (ignoring comments) are [T3, T2, T1]. In other
498   /// words, the tokens passed to this function need to the reverse of the
499   /// order the tokens appear in code.
500   template <typename A, typename... Ts>
501   bool endsSequence(A K1, Ts... Tokens) const {
502     return endsSequenceInternal(K1, Tokens...);
503   }
504 
505   bool isStringLiteral() const { return tok::isStringLiteral(Tok.getKind()); }
506 
507   bool isObjCAtKeyword(tok::ObjCKeywordKind Kind) const {
508     return Tok.isObjCAtKeyword(Kind);
509   }
510 
511   bool isAccessSpecifier(bool ColonRequired = true) const {
512     return isOneOf(tok::kw_public, tok::kw_protected, tok::kw_private) &&
513            (!ColonRequired || (Next && Next->is(tok::colon)));
514   }
515 
516   bool canBePointerOrReferenceQualifier() const {
517     return isOneOf(tok::kw_const, tok::kw_restrict, tok::kw_volatile,
518                    tok::kw___attribute, tok::kw__Nonnull, tok::kw__Nullable,
519                    tok::kw__Null_unspecified, tok::kw___ptr32, tok::kw___ptr64,
520                    TT_AttributeMacro);
521   }
522 
523   /// Determine whether the token is a simple-type-specifier.
524   bool isSimpleTypeSpecifier() const;
525 
526   bool isObjCAccessSpecifier() const {
527     return is(tok::at) && Next &&
528            (Next->isObjCAtKeyword(tok::objc_public) ||
529             Next->isObjCAtKeyword(tok::objc_protected) ||
530             Next->isObjCAtKeyword(tok::objc_package) ||
531             Next->isObjCAtKeyword(tok::objc_private));
532   }
533 
534   /// Returns whether \p Tok is ([{ or an opening < of a template or in
535   /// protos.
536   bool opensScope() const {
537     if (is(TT_TemplateString) && TokenText.endswith("${"))
538       return true;
539     if (is(TT_DictLiteral) && is(tok::less))
540       return true;
541     return isOneOf(tok::l_paren, tok::l_brace, tok::l_square,
542                    TT_TemplateOpener);
543   }
544   /// Returns whether \p Tok is )]} or a closing > of a template or in
545   /// protos.
546   bool closesScope() const {
547     if (is(TT_TemplateString) && TokenText.startswith("}"))
548       return true;
549     if (is(TT_DictLiteral) && is(tok::greater))
550       return true;
551     return isOneOf(tok::r_paren, tok::r_brace, tok::r_square,
552                    TT_TemplateCloser);
553   }
554 
555   /// Returns \c true if this is a "." or "->" accessing a member.
556   bool isMemberAccess() const {
557     return isOneOf(tok::arrow, tok::period, tok::arrowstar) &&
558            !isOneOf(TT_DesignatedInitializerPeriod, TT_TrailingReturnArrow,
559                     TT_LambdaArrow, TT_LeadingJavaAnnotation);
560   }
561 
562   bool isUnaryOperator() const {
563     switch (Tok.getKind()) {
564     case tok::plus:
565     case tok::plusplus:
566     case tok::minus:
567     case tok::minusminus:
568     case tok::exclaim:
569     case tok::tilde:
570     case tok::kw_sizeof:
571     case tok::kw_alignof:
572       return true;
573     default:
574       return false;
575     }
576   }
577 
578   bool isBinaryOperator() const {
579     // Comma is a binary operator, but does not behave as such wrt. formatting.
580     return getPrecedence() > prec::Comma;
581   }
582 
583   bool isTrailingComment() const {
584     return is(tok::comment) &&
585            (is(TT_LineComment) || !Next || Next->NewlinesBefore > 0);
586   }
587 
588   /// Returns \c true if this is a keyword that can be used
589   /// like a function call (e.g. sizeof, typeid, ...).
590   bool isFunctionLikeKeyword() const {
591     switch (Tok.getKind()) {
592     case tok::kw_throw:
593     case tok::kw_typeid:
594     case tok::kw_return:
595     case tok::kw_sizeof:
596     case tok::kw_alignof:
597     case tok::kw_alignas:
598     case tok::kw_decltype:
599     case tok::kw_noexcept:
600     case tok::kw_static_assert:
601     case tok::kw__Atomic:
602     case tok::kw___attribute:
603     case tok::kw___underlying_type:
604     case tok::kw_requires:
605       return true;
606     default:
607       return false;
608     }
609   }
610 
611   /// Returns \c true if this is a string literal that's like a label,
612   /// e.g. ends with "=" or ":".
613   bool isLabelString() const {
614     if (!is(tok::string_literal))
615       return false;
616     StringRef Content = TokenText;
617     if (Content.startswith("\"") || Content.startswith("'"))
618       Content = Content.drop_front(1);
619     if (Content.endswith("\"") || Content.endswith("'"))
620       Content = Content.drop_back(1);
621     Content = Content.trim();
622     return Content.size() > 1 &&
623            (Content.back() == ':' || Content.back() == '=');
624   }
625 
626   /// Returns actual token start location without leading escaped
627   /// newlines and whitespace.
628   ///
629   /// This can be different to Tok.getLocation(), which includes leading escaped
630   /// newlines.
631   SourceLocation getStartOfNonWhitespace() const {
632     return WhitespaceRange.getEnd();
633   }
634 
635   prec::Level getPrecedence() const {
636     return getBinOpPrecedence(Tok.getKind(), /*GreaterThanIsOperator=*/true,
637                               /*CPlusPlus11=*/true);
638   }
639 
640   /// Returns the previous token ignoring comments.
641   FormatToken *getPreviousNonComment() const {
642     FormatToken *Tok = Previous;
643     while (Tok && Tok->is(tok::comment))
644       Tok = Tok->Previous;
645     return Tok;
646   }
647 
648   /// Returns the next token ignoring comments.
649   const FormatToken *getNextNonComment() const {
650     const FormatToken *Tok = Next;
651     while (Tok && Tok->is(tok::comment))
652       Tok = Tok->Next;
653     return Tok;
654   }
655 
656   /// Returns \c true if this tokens starts a block-type list, i.e. a
657   /// list that should be indented with a block indent.
658   bool opensBlockOrBlockTypeList(const FormatStyle &Style) const {
659     // C# Does not indent object initialisers as continuations.
660     if (is(tok::l_brace) && getBlockKind() == BK_BracedInit && Style.isCSharp())
661       return true;
662     if (is(TT_TemplateString) && opensScope())
663       return true;
664     return is(TT_ArrayInitializerLSquare) || is(TT_ProtoExtensionLSquare) ||
665            (is(tok::l_brace) &&
666             (getBlockKind() == BK_Block || is(TT_DictLiteral) ||
667              (!Style.Cpp11BracedListStyle && NestingLevel == 0))) ||
668            (is(tok::less) && (Style.Language == FormatStyle::LK_Proto ||
669                               Style.Language == FormatStyle::LK_TextProto));
670   }
671 
672   /// Returns whether the token is the left square bracket of a C++
673   /// structured binding declaration.
674   bool isCppStructuredBinding(const FormatStyle &Style) const {
675     if (!Style.isCpp() || isNot(tok::l_square))
676       return false;
677     const FormatToken *T = this;
678     do {
679       T = T->getPreviousNonComment();
680     } while (T && T->isOneOf(tok::kw_const, tok::kw_volatile, tok::amp,
681                              tok::ampamp));
682     return T && T->is(tok::kw_auto);
683   }
684 
685   /// Same as opensBlockOrBlockTypeList, but for the closing token.
686   bool closesBlockOrBlockTypeList(const FormatStyle &Style) const {
687     if (is(TT_TemplateString) && closesScope())
688       return true;
689     return MatchingParen && MatchingParen->opensBlockOrBlockTypeList(Style);
690   }
691 
692   /// Return the actual namespace token, if this token starts a namespace
693   /// block.
694   const FormatToken *getNamespaceToken() const {
695     const FormatToken *NamespaceTok = this;
696     if (is(tok::comment))
697       NamespaceTok = NamespaceTok->getNextNonComment();
698     // Detect "(inline|export)? namespace" in the beginning of a line.
699     if (NamespaceTok && NamespaceTok->isOneOf(tok::kw_inline, tok::kw_export))
700       NamespaceTok = NamespaceTok->getNextNonComment();
701     return NamespaceTok &&
702                    NamespaceTok->isOneOf(tok::kw_namespace, TT_NamespaceMacro)
703                ? NamespaceTok
704                : nullptr;
705   }
706 
707   void copyFrom(const FormatToken &Tok) { *this = Tok; }
708 
709 private:
710   // Only allow copying via the explicit copyFrom method.
711   FormatToken(const FormatToken &) = delete;
712   FormatToken &operator=(const FormatToken &) = default;
713 
714   template <typename A, typename... Ts>
715   bool startsSequenceInternal(A K1, Ts... Tokens) const {
716     if (is(tok::comment) && Next)
717       return Next->startsSequenceInternal(K1, Tokens...);
718     return is(K1) && Next && Next->startsSequenceInternal(Tokens...);
719   }
720 
721   template <typename A> bool startsSequenceInternal(A K1) const {
722     if (is(tok::comment) && Next)
723       return Next->startsSequenceInternal(K1);
724     return is(K1);
725   }
726 
727   template <typename A, typename... Ts> bool endsSequenceInternal(A K1) const {
728     if (is(tok::comment) && Previous)
729       return Previous->endsSequenceInternal(K1);
730     return is(K1);
731   }
732 
733   template <typename A, typename... Ts>
734   bool endsSequenceInternal(A K1, Ts... Tokens) const {
735     if (is(tok::comment) && Previous)
736       return Previous->endsSequenceInternal(K1, Tokens...);
737     return is(K1) && Previous && Previous->endsSequenceInternal(Tokens...);
738   }
739 };
740 
741 class ContinuationIndenter;
742 struct LineState;
743 
744 class TokenRole {
745 public:
746   TokenRole(const FormatStyle &Style) : Style(Style) {}
747   virtual ~TokenRole();
748 
749   /// After the \c TokenAnnotator has finished annotating all the tokens,
750   /// this function precomputes required information for formatting.
751   virtual void precomputeFormattingInfos(const FormatToken *Token);
752 
753   /// Apply the special formatting that the given role demands.
754   ///
755   /// Assumes that the token having this role is already formatted.
756   ///
757   /// Continues formatting from \p State leaving indentation to \p Indenter and
758   /// returns the total penalty that this formatting incurs.
759   virtual unsigned formatFromToken(LineState &State,
760                                    ContinuationIndenter *Indenter,
761                                    bool DryRun) {
762     return 0;
763   }
764 
765   /// Same as \c formatFromToken, but assumes that the first token has
766   /// already been set thereby deciding on the first line break.
767   virtual unsigned formatAfterToken(LineState &State,
768                                     ContinuationIndenter *Indenter,
769                                     bool DryRun) {
770     return 0;
771   }
772 
773   /// Notifies the \c Role that a comma was found.
774   virtual void CommaFound(const FormatToken *Token) {}
775 
776   virtual const FormatToken *lastComma() { return nullptr; }
777 
778 protected:
779   const FormatStyle &Style;
780 };
781 
782 class CommaSeparatedList : public TokenRole {
783 public:
784   CommaSeparatedList(const FormatStyle &Style)
785       : TokenRole(Style), HasNestedBracedList(false) {}
786 
787   void precomputeFormattingInfos(const FormatToken *Token) override;
788 
789   unsigned formatAfterToken(LineState &State, ContinuationIndenter *Indenter,
790                             bool DryRun) override;
791 
792   unsigned formatFromToken(LineState &State, ContinuationIndenter *Indenter,
793                            bool DryRun) override;
794 
795   /// Adds \p Token as the next comma to the \c CommaSeparated list.
796   void CommaFound(const FormatToken *Token) override {
797     Commas.push_back(Token);
798   }
799 
800   const FormatToken *lastComma() override {
801     if (Commas.empty())
802       return nullptr;
803     return Commas.back();
804   }
805 
806 private:
807   /// A struct that holds information on how to format a given list with
808   /// a specific number of columns.
809   struct ColumnFormat {
810     /// The number of columns to use.
811     unsigned Columns;
812 
813     /// The total width in characters.
814     unsigned TotalWidth;
815 
816     /// The number of lines required for this format.
817     unsigned LineCount;
818 
819     /// The size of each column in characters.
820     SmallVector<unsigned, 8> ColumnSizes;
821   };
822 
823   /// Calculate which \c ColumnFormat fits best into
824   /// \p RemainingCharacters.
825   const ColumnFormat *getColumnFormat(unsigned RemainingCharacters) const;
826 
827   /// The ordered \c FormatTokens making up the commas of this list.
828   SmallVector<const FormatToken *, 8> Commas;
829 
830   /// The length of each of the list's items in characters including the
831   /// trailing comma.
832   SmallVector<unsigned, 8> ItemLengths;
833 
834   /// Precomputed formats that can be used for this list.
835   SmallVector<ColumnFormat, 4> Formats;
836 
837   bool HasNestedBracedList;
838 };
839 
840 /// Encapsulates keywords that are context sensitive or for languages not
841 /// properly supported by Clang's lexer.
842 struct AdditionalKeywords {
843   AdditionalKeywords(IdentifierTable &IdentTable) {
844     kw_final = &IdentTable.get("final");
845     kw_override = &IdentTable.get("override");
846     kw_in = &IdentTable.get("in");
847     kw_of = &IdentTable.get("of");
848     kw_CF_CLOSED_ENUM = &IdentTable.get("CF_CLOSED_ENUM");
849     kw_CF_ENUM = &IdentTable.get("CF_ENUM");
850     kw_CF_OPTIONS = &IdentTable.get("CF_OPTIONS");
851     kw_NS_CLOSED_ENUM = &IdentTable.get("NS_CLOSED_ENUM");
852     kw_NS_ENUM = &IdentTable.get("NS_ENUM");
853     kw_NS_OPTIONS = &IdentTable.get("NS_OPTIONS");
854 
855     kw_as = &IdentTable.get("as");
856     kw_async = &IdentTable.get("async");
857     kw_await = &IdentTable.get("await");
858     kw_declare = &IdentTable.get("declare");
859     kw_finally = &IdentTable.get("finally");
860     kw_from = &IdentTable.get("from");
861     kw_function = &IdentTable.get("function");
862     kw_get = &IdentTable.get("get");
863     kw_import = &IdentTable.get("import");
864     kw_infer = &IdentTable.get("infer");
865     kw_is = &IdentTable.get("is");
866     kw_let = &IdentTable.get("let");
867     kw_module = &IdentTable.get("module");
868     kw_readonly = &IdentTable.get("readonly");
869     kw_set = &IdentTable.get("set");
870     kw_type = &IdentTable.get("type");
871     kw_typeof = &IdentTable.get("typeof");
872     kw_var = &IdentTable.get("var");
873     kw_yield = &IdentTable.get("yield");
874 
875     kw_abstract = &IdentTable.get("abstract");
876     kw_assert = &IdentTable.get("assert");
877     kw_extends = &IdentTable.get("extends");
878     kw_implements = &IdentTable.get("implements");
879     kw_instanceof = &IdentTable.get("instanceof");
880     kw_interface = &IdentTable.get("interface");
881     kw_native = &IdentTable.get("native");
882     kw_package = &IdentTable.get("package");
883     kw_synchronized = &IdentTable.get("synchronized");
884     kw_throws = &IdentTable.get("throws");
885     kw___except = &IdentTable.get("__except");
886     kw___has_include = &IdentTable.get("__has_include");
887     kw___has_include_next = &IdentTable.get("__has_include_next");
888 
889     kw_mark = &IdentTable.get("mark");
890 
891     kw_extend = &IdentTable.get("extend");
892     kw_option = &IdentTable.get("option");
893     kw_optional = &IdentTable.get("optional");
894     kw_repeated = &IdentTable.get("repeated");
895     kw_required = &IdentTable.get("required");
896     kw_returns = &IdentTable.get("returns");
897 
898     kw_signals = &IdentTable.get("signals");
899     kw_qsignals = &IdentTable.get("Q_SIGNALS");
900     kw_slots = &IdentTable.get("slots");
901     kw_qslots = &IdentTable.get("Q_SLOTS");
902 
903     // C# keywords
904     kw_dollar = &IdentTable.get("dollar");
905     kw_base = &IdentTable.get("base");
906     kw_byte = &IdentTable.get("byte");
907     kw_checked = &IdentTable.get("checked");
908     kw_decimal = &IdentTable.get("decimal");
909     kw_delegate = &IdentTable.get("delegate");
910     kw_event = &IdentTable.get("event");
911     kw_fixed = &IdentTable.get("fixed");
912     kw_foreach = &IdentTable.get("foreach");
913     kw_implicit = &IdentTable.get("implicit");
914     kw_internal = &IdentTable.get("internal");
915     kw_lock = &IdentTable.get("lock");
916     kw_null = &IdentTable.get("null");
917     kw_object = &IdentTable.get("object");
918     kw_out = &IdentTable.get("out");
919     kw_params = &IdentTable.get("params");
920     kw_ref = &IdentTable.get("ref");
921     kw_string = &IdentTable.get("string");
922     kw_stackalloc = &IdentTable.get("stackalloc");
923     kw_sbyte = &IdentTable.get("sbyte");
924     kw_sealed = &IdentTable.get("sealed");
925     kw_uint = &IdentTable.get("uint");
926     kw_ulong = &IdentTable.get("ulong");
927     kw_unchecked = &IdentTable.get("unchecked");
928     kw_unsafe = &IdentTable.get("unsafe");
929     kw_ushort = &IdentTable.get("ushort");
930     kw_when = &IdentTable.get("when");
931     kw_where = &IdentTable.get("where");
932 
933     // Keep this at the end of the constructor to make sure everything here
934     // is
935     // already initialized.
936     JsExtraKeywords = std::unordered_set<IdentifierInfo *>(
937         {kw_as, kw_async, kw_await, kw_declare, kw_finally, kw_from,
938          kw_function, kw_get, kw_import, kw_is, kw_let, kw_module, kw_override,
939          kw_readonly, kw_set, kw_type, kw_typeof, kw_var, kw_yield,
940          // Keywords from the Java section.
941          kw_abstract, kw_extends, kw_implements, kw_instanceof, kw_interface});
942 
943     CSharpExtraKeywords = std::unordered_set<IdentifierInfo *>(
944         {kw_base, kw_byte, kw_checked, kw_decimal, kw_delegate, kw_event,
945          kw_fixed, kw_foreach, kw_implicit, kw_in, kw_interface, kw_internal,
946          kw_is, kw_lock, kw_null, kw_object, kw_out, kw_override, kw_params,
947          kw_readonly, kw_ref, kw_string, kw_stackalloc, kw_sbyte, kw_sealed,
948          kw_uint, kw_ulong, kw_unchecked, kw_unsafe, kw_ushort, kw_when,
949          kw_where,
950          // Keywords from the JavaScript section.
951          kw_as, kw_async, kw_await, kw_declare, kw_finally, kw_from,
952          kw_function, kw_get, kw_import, kw_is, kw_let, kw_module, kw_readonly,
953          kw_set, kw_type, kw_typeof, kw_var, kw_yield,
954          // Keywords from the Java section.
955          kw_abstract, kw_extends, kw_implements, kw_instanceof, kw_interface});
956   }
957 
958   // Context sensitive keywords.
959   IdentifierInfo *kw_final;
960   IdentifierInfo *kw_override;
961   IdentifierInfo *kw_in;
962   IdentifierInfo *kw_of;
963   IdentifierInfo *kw_CF_CLOSED_ENUM;
964   IdentifierInfo *kw_CF_ENUM;
965   IdentifierInfo *kw_CF_OPTIONS;
966   IdentifierInfo *kw_NS_CLOSED_ENUM;
967   IdentifierInfo *kw_NS_ENUM;
968   IdentifierInfo *kw_NS_OPTIONS;
969   IdentifierInfo *kw___except;
970   IdentifierInfo *kw___has_include;
971   IdentifierInfo *kw___has_include_next;
972 
973   // JavaScript keywords.
974   IdentifierInfo *kw_as;
975   IdentifierInfo *kw_async;
976   IdentifierInfo *kw_await;
977   IdentifierInfo *kw_declare;
978   IdentifierInfo *kw_finally;
979   IdentifierInfo *kw_from;
980   IdentifierInfo *kw_function;
981   IdentifierInfo *kw_get;
982   IdentifierInfo *kw_import;
983   IdentifierInfo *kw_infer;
984   IdentifierInfo *kw_is;
985   IdentifierInfo *kw_let;
986   IdentifierInfo *kw_module;
987   IdentifierInfo *kw_readonly;
988   IdentifierInfo *kw_set;
989   IdentifierInfo *kw_type;
990   IdentifierInfo *kw_typeof;
991   IdentifierInfo *kw_var;
992   IdentifierInfo *kw_yield;
993 
994   // Java keywords.
995   IdentifierInfo *kw_abstract;
996   IdentifierInfo *kw_assert;
997   IdentifierInfo *kw_extends;
998   IdentifierInfo *kw_implements;
999   IdentifierInfo *kw_instanceof;
1000   IdentifierInfo *kw_interface;
1001   IdentifierInfo *kw_native;
1002   IdentifierInfo *kw_package;
1003   IdentifierInfo *kw_synchronized;
1004   IdentifierInfo *kw_throws;
1005 
1006   // Pragma keywords.
1007   IdentifierInfo *kw_mark;
1008 
1009   // Proto keywords.
1010   IdentifierInfo *kw_extend;
1011   IdentifierInfo *kw_option;
1012   IdentifierInfo *kw_optional;
1013   IdentifierInfo *kw_repeated;
1014   IdentifierInfo *kw_required;
1015   IdentifierInfo *kw_returns;
1016 
1017   // QT keywords.
1018   IdentifierInfo *kw_signals;
1019   IdentifierInfo *kw_qsignals;
1020   IdentifierInfo *kw_slots;
1021   IdentifierInfo *kw_qslots;
1022 
1023   // C# keywords
1024   IdentifierInfo *kw_dollar;
1025   IdentifierInfo *kw_base;
1026   IdentifierInfo *kw_byte;
1027   IdentifierInfo *kw_checked;
1028   IdentifierInfo *kw_decimal;
1029   IdentifierInfo *kw_delegate;
1030   IdentifierInfo *kw_event;
1031   IdentifierInfo *kw_fixed;
1032   IdentifierInfo *kw_foreach;
1033   IdentifierInfo *kw_implicit;
1034   IdentifierInfo *kw_internal;
1035 
1036   IdentifierInfo *kw_lock;
1037   IdentifierInfo *kw_null;
1038   IdentifierInfo *kw_object;
1039   IdentifierInfo *kw_out;
1040 
1041   IdentifierInfo *kw_params;
1042 
1043   IdentifierInfo *kw_ref;
1044   IdentifierInfo *kw_string;
1045   IdentifierInfo *kw_stackalloc;
1046   IdentifierInfo *kw_sbyte;
1047   IdentifierInfo *kw_sealed;
1048   IdentifierInfo *kw_uint;
1049   IdentifierInfo *kw_ulong;
1050   IdentifierInfo *kw_unchecked;
1051   IdentifierInfo *kw_unsafe;
1052   IdentifierInfo *kw_ushort;
1053   IdentifierInfo *kw_when;
1054   IdentifierInfo *kw_where;
1055 
1056   /// Returns \c true if \p Tok is a true JavaScript identifier, returns
1057   /// \c false if it is a keyword or a pseudo keyword.
1058   /// If \c AcceptIdentifierName is true, returns true not only for keywords,
1059   // but also for IdentifierName tokens (aka pseudo-keywords), such as
1060   // ``yield``.
1061   bool IsJavaScriptIdentifier(const FormatToken &Tok,
1062                               bool AcceptIdentifierName = true) const {
1063     // Based on the list of JavaScript & TypeScript keywords here:
1064     // https://github.com/microsoft/TypeScript/blob/main/src/compiler/scanner.ts#L74
1065     switch (Tok.Tok.getKind()) {
1066     case tok::kw_break:
1067     case tok::kw_case:
1068     case tok::kw_catch:
1069     case tok::kw_class:
1070     case tok::kw_continue:
1071     case tok::kw_const:
1072     case tok::kw_default:
1073     case tok::kw_delete:
1074     case tok::kw_do:
1075     case tok::kw_else:
1076     case tok::kw_enum:
1077     case tok::kw_export:
1078     case tok::kw_false:
1079     case tok::kw_for:
1080     case tok::kw_if:
1081     case tok::kw_import:
1082     case tok::kw_module:
1083     case tok::kw_new:
1084     case tok::kw_private:
1085     case tok::kw_protected:
1086     case tok::kw_public:
1087     case tok::kw_return:
1088     case tok::kw_static:
1089     case tok::kw_switch:
1090     case tok::kw_this:
1091     case tok::kw_throw:
1092     case tok::kw_true:
1093     case tok::kw_try:
1094     case tok::kw_typeof:
1095     case tok::kw_void:
1096     case tok::kw_while:
1097       // These are JS keywords that are lexed by LLVM/clang as keywords.
1098       return false;
1099     case tok::identifier: {
1100       // For identifiers, make sure they are true identifiers, excluding the
1101       // JavaScript pseudo-keywords (not lexed by LLVM/clang as keywords).
1102       bool IsPseudoKeyword =
1103           JsExtraKeywords.find(Tok.Tok.getIdentifierInfo()) !=
1104           JsExtraKeywords.end();
1105       return AcceptIdentifierName || !IsPseudoKeyword;
1106     }
1107     default:
1108       // Other keywords are handled in the switch below, to avoid problems due
1109       // to duplicate case labels when using the #include trick.
1110       break;
1111     }
1112 
1113     switch (Tok.Tok.getKind()) {
1114       // Handle C++ keywords not included above: these are all JS identifiers.
1115 #define KEYWORD(X, Y) case tok::kw_##X:
1116 #include "clang/Basic/TokenKinds.def"
1117       // #undef KEYWORD is not needed -- it's #undef-ed at the end of
1118       // TokenKinds.def
1119       return true;
1120     default:
1121       // All other tokens (punctuation etc) are not JS identifiers.
1122       return false;
1123     }
1124   }
1125 
1126   /// Returns \c true if \p Tok is a C# keyword, returns
1127   /// \c false if it is a anything else.
1128   bool isCSharpKeyword(const FormatToken &Tok) const {
1129     switch (Tok.Tok.getKind()) {
1130     case tok::kw_bool:
1131     case tok::kw_break:
1132     case tok::kw_case:
1133     case tok::kw_catch:
1134     case tok::kw_char:
1135     case tok::kw_class:
1136     case tok::kw_const:
1137     case tok::kw_continue:
1138     case tok::kw_default:
1139     case tok::kw_do:
1140     case tok::kw_double:
1141     case tok::kw_else:
1142     case tok::kw_enum:
1143     case tok::kw_explicit:
1144     case tok::kw_extern:
1145     case tok::kw_false:
1146     case tok::kw_float:
1147     case tok::kw_for:
1148     case tok::kw_goto:
1149     case tok::kw_if:
1150     case tok::kw_int:
1151     case tok::kw_long:
1152     case tok::kw_namespace:
1153     case tok::kw_new:
1154     case tok::kw_operator:
1155     case tok::kw_private:
1156     case tok::kw_protected:
1157     case tok::kw_public:
1158     case tok::kw_return:
1159     case tok::kw_short:
1160     case tok::kw_sizeof:
1161     case tok::kw_static:
1162     case tok::kw_struct:
1163     case tok::kw_switch:
1164     case tok::kw_this:
1165     case tok::kw_throw:
1166     case tok::kw_true:
1167     case tok::kw_try:
1168     case tok::kw_typeof:
1169     case tok::kw_using:
1170     case tok::kw_virtual:
1171     case tok::kw_void:
1172     case tok::kw_volatile:
1173     case tok::kw_while:
1174       return true;
1175     default:
1176       return Tok.is(tok::identifier) &&
1177              CSharpExtraKeywords.find(Tok.Tok.getIdentifierInfo()) ==
1178                  CSharpExtraKeywords.end();
1179     }
1180   }
1181 
1182 private:
1183   /// The JavaScript keywords beyond the C++ keyword set.
1184   std::unordered_set<IdentifierInfo *> JsExtraKeywords;
1185 
1186   /// The C# keywords beyond the C++ keyword set
1187   std::unordered_set<IdentifierInfo *> CSharpExtraKeywords;
1188 };
1189 
1190 } // namespace format
1191 } // namespace clang
1192 
1193 #endif
1194