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