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