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