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